anno_start anno_end anno_text entity_type sentence section 61 78 estrogen receptor protein_type Predictive features of ligand‐specific signaling through the estrogen receptor TITLE 5 24 estrogen receptor‐α protein Some estrogen receptor‐α (ERα)‐targeted breast cancer therapies such as tamoxifen have tissue‐selective or cell‐specific activities, while others have similar activities in different cell types. ABSTRACT 26 29 ERα protein Some estrogen receptor‐α (ERα)‐targeted breast cancer therapies such as tamoxifen have tissue‐selective or cell‐specific activities, while others have similar activities in different cell types. ABSTRACT 72 81 tamoxifen chemical Some estrogen receptor‐α (ERα)‐targeted breast cancer therapies such as tamoxifen have tissue‐selective or cell‐specific activities, while others have similar activities in different cell types. ABSTRACT 105 116 synthesized experimental_method To identify biophysical determinants of cell‐specific signaling and breast cancer cell proliferation, we synthesized 241 ERα ligands based on 19 chemical scaffolds, and compared ligand response using quantitative bioassays for canonical ERα activities and X‐ray crystallography. ABSTRACT 121 124 ERα protein To identify biophysical determinants of cell‐specific signaling and breast cancer cell proliferation, we synthesized 241 ERα ligands based on 19 chemical scaffolds, and compared ligand response using quantitative bioassays for canonical ERα activities and X‐ray crystallography. ABSTRACT 200 222 quantitative bioassays experimental_method To identify biophysical determinants of cell‐specific signaling and breast cancer cell proliferation, we synthesized 241 ERα ligands based on 19 chemical scaffolds, and compared ligand response using quantitative bioassays for canonical ERα activities and X‐ray crystallography. ABSTRACT 237 240 ERα protein To identify biophysical determinants of cell‐specific signaling and breast cancer cell proliferation, we synthesized 241 ERα ligands based on 19 chemical scaffolds, and compared ligand response using quantitative bioassays for canonical ERα activities and X‐ray crystallography. ABSTRACT 256 277 X‐ray crystallography experimental_method To identify biophysical determinants of cell‐specific signaling and breast cancer cell proliferation, we synthesized 241 ERα ligands based on 19 chemical scaffolds, and compared ligand response using quantitative bioassays for canonical ERα activities and X‐ray crystallography. ABSTRACT 56 80 coactivator‐binding site site Ligands that regulate the dynamics and stability of the coactivator‐binding site in the C‐terminal ligand‐binding domain, called activation function‐2 (AF‐2), showed similar activity profiles in different cell types. ABSTRACT 99 120 ligand‐binding domain structure_element Ligands that regulate the dynamics and stability of the coactivator‐binding site in the C‐terminal ligand‐binding domain, called activation function‐2 (AF‐2), showed similar activity profiles in different cell types. ABSTRACT 129 150 activation function‐2 structure_element Ligands that regulate the dynamics and stability of the coactivator‐binding site in the C‐terminal ligand‐binding domain, called activation function‐2 (AF‐2), showed similar activity profiles in different cell types. ABSTRACT 152 156 AF‐2 structure_element Ligands that regulate the dynamics and stability of the coactivator‐binding site in the C‐terminal ligand‐binding domain, called activation function‐2 (AF‐2), showed similar activity profiles in different cell types. ABSTRACT 134 143 NCOA1/2/3 protein Such ligands induced breast cancer cell proliferation in a manner that was predicted by the canonical recruitment of the coactivators NCOA1/2/3 and induction of the GREB1 proliferative gene. ABSTRACT 165 170 GREB1 protein Such ligands induced breast cancer cell proliferation in a manner that was predicted by the canonical recruitment of the coactivators NCOA1/2/3 and induction of the GREB1 proliferative gene. ABSTRACT 33 54 inter‐atomic distance evidence For some ligand series, a single inter‐atomic distance in the ligand‐binding domain predicted their proliferative effects. ABSTRACT 62 83 ligand‐binding domain structure_element For some ligand series, a single inter‐atomic distance in the ligand‐binding domain predicted their proliferative effects. ABSTRACT 28 52 coactivator‐binding site site In contrast, the N‐terminal coactivator‐binding site, activation function‐1 (AF‐1), determined cell‐specific signaling induced by ligands that used alternate mechanisms to control cell proliferation. ABSTRACT 54 75 activation function‐1 structure_element In contrast, the N‐terminal coactivator‐binding site, activation function‐1 (AF‐1), determined cell‐specific signaling induced by ligands that used alternate mechanisms to control cell proliferation. ABSTRACT 77 81 AF‐1 structure_element In contrast, the N‐terminal coactivator‐binding site, activation function‐1 (AF‐1), determined cell‐specific signaling induced by ligands that used alternate mechanisms to control cell proliferation. ABSTRACT 20 47 systems structural analyses experimental_method Thus, incorporating systems structural analyses with quantitative chemical biology reveals how ligands can achieve distinct allosteric signaling outcomes through ERα. ABSTRACT 53 82 quantitative chemical biology experimental_method Thus, incorporating systems structural analyses with quantitative chemical biology reveals how ligands can achieve distinct allosteric signaling outcomes through ERα. ABSTRACT 162 165 ERα protein Thus, incorporating systems structural analyses with quantitative chemical biology reveals how ligands can achieve distinct allosteric signaling outcomes through ERα. ABSTRACT 82 109 G protein‐coupled receptors protein_type Many drugs are small‐molecule ligands of allosteric signaling proteins, including G protein‐coupled receptors (GPCRs) and nuclear receptors such as ERα. INTRO 111 116 GPCRs protein_type Many drugs are small‐molecule ligands of allosteric signaling proteins, including G protein‐coupled receptors (GPCRs) and nuclear receptors such as ERα. INTRO 122 139 nuclear receptors protein_type Many drugs are small‐molecule ligands of allosteric signaling proteins, including G protein‐coupled receptors (GPCRs) and nuclear receptors such as ERα. INTRO 148 151 ERα protein Many drugs are small‐molecule ligands of allosteric signaling proteins, including G protein‐coupled receptors (GPCRs) and nuclear receptors such as ERα. INTRO 146 165 ligand‐binding site site Small‐molecule ligands control receptor activity by modulating recruitment of effector enzymes to distal regions of the receptor, relative to the ligand‐binding site. INTRO 23 51 estrogen receptor modulators protein_type For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 53 58 SERMs protein_type For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 68 77 tamoxifen chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 79 88 Nolvadex® chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 106 116 raloxifene chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 118 125 Evista® chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 157 160 ERα protein For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 206 214 estrogen chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 216 229 17β‐estradiol chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 231 233 E2 chemical For example, selective estrogen receptor modulators (SERMs) such as tamoxifen (Nolvadex®; AstraZeneca) or raloxifene (Evista®; Eli Lilly) (Fig 1A) block the ERα‐mediated proliferative effects of the native estrogen, 17β‐estradiol (E2), on breast cancer cells, but promote beneficial estrogenic effects on bone mineral density and adverse estrogenic effects such as uterine proliferation, fatty liver, or stroke (Frolik et al, 1996; Fisher et al, 1998; McDonnell et al, 2002; Jordan, 2003). INTRO 22 25 ERα protein Allosteric control of ERα activity FIG 35 38 ERα protein Chemical structures of some common ERα ligands. FIG 0 2 E2 chemical E2‐rings are numbered A‐D. The E‐ring is the common site of attachment for BSC found in many SERMS. FIG 93 98 SERMS protein_type E2‐rings are numbered A‐D. The E‐ring is the common site of attachment for BSC found in many SERMS. FIG 0 3 ERα protein ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 39 42 DBD structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 44 62 DNA‐binding domain structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 64 67 LBD structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 69 90 ligand‐binding domain structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 92 94 AF structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 96 115 activation function structure_element ERα domain organization lettered, A‐F. DBD, DNA‐binding domain; LBD, ligand‐binding domain; AF, activation function FIG 40 43 ERα protein Schematic illustration of the canonical ERα signaling pathway. FIG 27 30 ERα protein Linear causality model for ERα‐mediated cell proliferation. FIG 29 32 ERα protein Branched causality model for ERα‐mediated cell proliferation. FIG 0 3 ERα protein ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 13 35 structurally conserved protein_state ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 36 52 globular domains structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 60 88 nuclear receptor superfamily protein_type ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 102 120 DNA‐binding domain structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 122 125 DBD structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 150 158 flexible protein_state ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 159 171 hinge region structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 179 200 ligand‐binding domain structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 202 205 LBD structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 219 231 unstructured protein_state ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 232 234 AB structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 239 240 F structure_element ERα contains structurally conserved globular domains of the nuclear receptor superfamily, including a DNA‐binding domain (DBD) that is connected by a flexible hinge region to the ligand‐binding domain (LBD), as well as unstructured AB and F domains at its amino and carboxyl termini, respectively (Fig 1B). INTRO 4 7 LBD structure_element The LBD contains a ligand‐dependent coactivator‐binding site called activation function‐2 (AF‐2). INTRO 36 60 coactivator‐binding site site The LBD contains a ligand‐dependent coactivator‐binding site called activation function‐2 (AF‐2). INTRO 68 89 activation function‐2 structure_element The LBD contains a ligand‐dependent coactivator‐binding site called activation function‐2 (AF‐2). INTRO 91 95 AF‐2 structure_element The LBD contains a ligand‐dependent coactivator‐binding site called activation function‐2 (AF‐2). INTRO 33 38 SERMs protein_type However, the agonist activity of SERMs derives from activation function‐1 (AF‐1)—a coactivator recruitment site located in the AB domain (Berry et al, 1990; Shang & Brown, 2002; Abot et al, 2013). INTRO 52 73 activation function‐1 structure_element However, the agonist activity of SERMs derives from activation function‐1 (AF‐1)—a coactivator recruitment site located in the AB domain (Berry et al, 1990; Shang & Brown, 2002; Abot et al, 2013). INTRO 75 79 AF‐1 structure_element However, the agonist activity of SERMs derives from activation function‐1 (AF‐1)—a coactivator recruitment site located in the AB domain (Berry et al, 1990; Shang & Brown, 2002; Abot et al, 2013). INTRO 83 111 coactivator recruitment site site However, the agonist activity of SERMs derives from activation function‐1 (AF‐1)—a coactivator recruitment site located in the AB domain (Berry et al, 1990; Shang & Brown, 2002; Abot et al, 2013). INTRO 127 129 AB structure_element However, the agonist activity of SERMs derives from activation function‐1 (AF‐1)—a coactivator recruitment site located in the AB domain (Berry et al, 1990; Shang & Brown, 2002; Abot et al, 2013). INTRO 0 4 AF‐1 structure_element AF‐1 and AF‐2 bind distinct but overlapping sets of coregulators (Webb et al, 1998; Endoh et al, 1999; Delage‐Mourroux et al, 2000; Yi et al, 2015). INTRO 9 13 AF‐2 structure_element AF‐1 and AF‐2 bind distinct but overlapping sets of coregulators (Webb et al, 1998; Endoh et al, 1999; Delage‐Mourroux et al, 2000; Yi et al, 2015). INTRO 0 4 AF‐2 structure_element AF‐2 binds the signature LxxLL motif peptides of coactivators such as NCOA1/2/3 (also known as SRC‐1/2/3). INTRO 25 36 LxxLL motif structure_element AF‐2 binds the signature LxxLL motif peptides of coactivators such as NCOA1/2/3 (also known as SRC‐1/2/3). INTRO 70 79 NCOA1/2/3 protein AF‐2 binds the signature LxxLL motif peptides of coactivators such as NCOA1/2/3 (also known as SRC‐1/2/3). INTRO 95 104 SRC‐1/2/3 protein AF‐2 binds the signature LxxLL motif peptides of coactivators such as NCOA1/2/3 (also known as SRC‐1/2/3). INTRO 0 4 AF‐1 structure_element AF‐1 binds a separate surface on these coactivators (Webb et al, 1998; Yi et al, 2015). INTRO 33 36 ERα protein Yet, it is unknown how different ERα ligands control AF‐1 through the LBD, and whether this inter‐domain communication is required for cell‐specific signaling or anti‐proliferative responses. INTRO 53 57 AF‐1 structure_element Yet, it is unknown how different ERα ligands control AF‐1 through the LBD, and whether this inter‐domain communication is required for cell‐specific signaling or anti‐proliferative responses. INTRO 70 73 LBD structure_element Yet, it is unknown how different ERα ligands control AF‐1 through the LBD, and whether this inter‐domain communication is required for cell‐specific signaling or anti‐proliferative responses. INTRO 30 33 ERα protein In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 62 70 E2‐bound protein_state In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 71 74 ERα protein In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 83 92 homodimer oligomeric_state In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 111 137 estrogen‐response elements site In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 139 143 EREs site In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 155 164 NCOA1/2/3 protein In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 233 238 GREB1 protein In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 284 287 ERα protein In the canonical model of the ERα signaling pathway (Fig 1C), E2‐bound ERα forms a homodimer that binds DNA at estrogen‐response elements (EREs), recruits NCOA1/2/3 (Metivier et al, 2003; Johnson & O'Malley, 2012), and activates the GREB1 gene, which is required for proliferation of ERα‐positive breast cancer cells (Ghosh et al, 2000; Rae et al, 2005; Deschenes et al, 2007; Liu et al, 2012; Srinivasan et al, 2013). INTRO 9 12 ERα protein However, ERα‐mediated proliferative responses vary in a ligand‐dependent manner (Srinivasan et al, 2013); thus, it is not known whether this canonical model is widely applicable across diverse ERα ligands. INTRO 193 196 ERα protein However, ERα‐mediated proliferative responses vary in a ligand‐dependent manner (Srinivasan et al, 2013); thus, it is not known whether this canonical model is widely applicable across diverse ERα ligands. INTRO 131 148 crystal structure evidence Our long‐term goal is to be able to predict proliferative or anti‐proliferative activity of a ligand in different tissues from its crystal structure by identifying different structural perturbations that lead to specific signaling outcomes. INTRO 119 128 NCOA1/2/3 protein The simplest response model for ligand‐specific proliferative effects is a linear causality model, where the degree of NCOA1/2/3 recruitment determines GREB1 expression, which in turn drives ligand‐specific cell proliferation (Fig 1D). INTRO 152 157 GREB1 protein The simplest response model for ligand‐specific proliferative effects is a linear causality model, where the degree of NCOA1/2/3 recruitment determines GREB1 expression, which in turn drives ligand‐specific cell proliferation (Fig 1D). INTRO 126 129 LBD structure_element In this signaling model, multiple coregulator binding events and target genes (Won Jeong et al, 2012; Nwachukwu et al, 2014), LBD conformation, nucleocytoplasmic shuttling, the occupancy and dynamics of DNA binding, and other biophysical features could contribute independently to cell proliferation (Lickwar et al, 2012). INTRO 65 68 ERα protein To test these signaling models, we profiled a diverse library of ERα ligands using systems biology approaches to X‐ray crystallography and chemical biology (Srinivasan et al, 2013), including a series of quantitative bioassays for ERα function that were statistically robust and reproducible, based on the Z’‐statistic (Fig EV1A and B; see Materials and Methods). INTRO 113 134 X‐ray crystallography experimental_method To test these signaling models, we profiled a diverse library of ERα ligands using systems biology approaches to X‐ray crystallography and chemical biology (Srinivasan et al, 2013), including a series of quantitative bioassays for ERα function that were statistically robust and reproducible, based on the Z’‐statistic (Fig EV1A and B; see Materials and Methods). INTRO 139 155 chemical biology experimental_method To test these signaling models, we profiled a diverse library of ERα ligands using systems biology approaches to X‐ray crystallography and chemical biology (Srinivasan et al, 2013), including a series of quantitative bioassays for ERα function that were statistically robust and reproducible, based on the Z’‐statistic (Fig EV1A and B; see Materials and Methods). INTRO 231 234 ERα protein To test these signaling models, we profiled a diverse library of ERα ligands using systems biology approaches to X‐ray crystallography and chemical biology (Srinivasan et al, 2013), including a series of quantitative bioassays for ERα function that were statistically robust and reproducible, based on the Z’‐statistic (Fig EV1A and B; see Materials and Methods). INTRO 306 318 Z’‐statistic evidence To test these signaling models, we profiled a diverse library of ERα ligands using systems biology approaches to X‐ray crystallography and chemical biology (Srinivasan et al, 2013), including a series of quantitative bioassays for ERα function that were statistically robust and reproducible, based on the Z’‐statistic (Fig EV1A and B; see Materials and Methods). INTRO 8 18 determined experimental_method We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 23 33 structures evidence We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 49 52 ERα protein We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 53 56 LBD structure_element We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 67 75 bound to protein_state We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 172 178 active protein_state We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 199 202 ERα protein We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 203 206 LBD structure_element We also determined the structures of 76 distinct ERα LBD complexes bound to different ligand types, which allowed us to understand how diverse ligand scaffolds distort the active conformation of the ERα LBD. INTRO 297 306 estrogens chemical Our findings here indicate that specific structural perturbations can be tied to ligand‐selective domain usage and signaling patterns, thus providing a framework for structure‐based design of improved breast cancer therapeutics, and understanding the different phenotypic effects of environmental estrogens. INTRO 28 31 ERα protein High‐throughput screens for ERα ligand profiling FIG 11 34 ligand screening assays experimental_method Summary of ligand screening assays used to measure ER‐mediated activities. FIG 0 3 ERE structure_element ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 5 30 estrogen‐response element structure_element ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 32 35 Luc experimental_method ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 37 61 luciferase reporter gene experimental_method ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 63 66 M2H experimental_method ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 68 86 mammalian 2‐hybrid experimental_method ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 88 91 UAS structure_element ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 93 121 upstream‐activating sequence structure_element ERE, estrogen‐response element; Luc, luciferase reporter gene; M2H, mammalian 2‐hybrid; UAS, upstream‐activating sequence. FIG 12 16 AF‐1 structure_element Strength of AF‐1 signaling does not determine cell‐specific signaling RESULTS 11 14 ERα protein To compare ERα signaling induced by diverse ligand types, we synthesized and assayed a library of 241 ERα ligands containing 19 distinct molecular scaffolds. RESULTS 61 84 synthesized and assayed experimental_method To compare ERα signaling induced by diverse ligand types, we synthesized and assayed a library of 241 ERα ligands containing 19 distinct molecular scaffolds. RESULTS 102 105 ERα protein To compare ERα signaling induced by diverse ligand types, we synthesized and assayed a library of 241 ERα ligands containing 19 distinct molecular scaffolds. RESULTS 50 54 lack protein_state These include 15 indirect modulator series, which lack a SERM‐like side chain and modulate coactivator binding indirectly from the ligand‐binding pocket (Fig 2A–E; Dataset EV1) (Zheng et al, 2012) (Zhu et al, 2012) (Muthyala et al, 2003; Seo et al, 2006) (Srinivasan et al, 2013) (Wang et al, 2012) (Liao et al, 2014) (Min et al, 2013). RESULTS 57 66 SERM‐like protein_type These include 15 indirect modulator series, which lack a SERM‐like side chain and modulate coactivator binding indirectly from the ligand‐binding pocket (Fig 2A–E; Dataset EV1) (Zheng et al, 2012) (Zhu et al, 2012) (Muthyala et al, 2003; Seo et al, 2006) (Srinivasan et al, 2013) (Wang et al, 2012) (Liao et al, 2014) (Min et al, 2013). RESULTS 131 152 ligand‐binding pocket site These include 15 indirect modulator series, which lack a SERM‐like side chain and modulate coactivator binding indirectly from the ligand‐binding pocket (Fig 2A–E; Dataset EV1) (Zheng et al, 2012) (Zhu et al, 2012) (Muthyala et al, 2003; Seo et al, 2006) (Srinivasan et al, 2013) (Wang et al, 2012) (Liao et al, 2014) (Min et al, 2013). RESULTS 95 98 h12 structure_element We also generated four direct modulator series with side chains designed to directly dislocate h12 and thereby completely occlude the AF‐2 surface (Fig 2C and E; Dataset EV1) (Kieser et al, 2010). RESULTS 134 146 AF‐2 surface site We also generated four direct modulator series with side chains designed to directly dislocate h12 and thereby completely occlude the AF‐2 surface (Fig 2C and E; Dataset EV1) (Kieser et al, 2010). RESULTS 0 16 Ligand profiling experimental_method Ligand profiling using our quantitative bioassays revealed a wide range of ligand‐induced GREB1 expression, reporter gene activities, ERα‐coactivator interactions, and proliferative effects on MCF‐7 breast cancer cells (Figs EV1 and EV2A–J). RESULTS 27 49 quantitative bioassays experimental_method Ligand profiling using our quantitative bioassays revealed a wide range of ligand‐induced GREB1 expression, reporter gene activities, ERα‐coactivator interactions, and proliferative effects on MCF‐7 breast cancer cells (Figs EV1 and EV2A–J). RESULTS 90 95 GREB1 protein Ligand profiling using our quantitative bioassays revealed a wide range of ligand‐induced GREB1 expression, reporter gene activities, ERα‐coactivator interactions, and proliferative effects on MCF‐7 breast cancer cells (Figs EV1 and EV2A–J). RESULTS 134 137 ERα protein Ligand profiling using our quantitative bioassays revealed a wide range of ligand‐induced GREB1 expression, reporter gene activities, ERα‐coactivator interactions, and proliferative effects on MCF‐7 breast cancer cells (Figs EV1 and EV2A–J). RESULTS 60 63 ERα protein This wide variance enabled us to probe specific features of ERα signaling using ligand class analyses, and identify signaling patterns shared by specific ligand series or scaffolds. RESULTS 80 101 ligand class analyses experimental_method This wide variance enabled us to probe specific features of ERα signaling using ligand class analyses, and identify signaling patterns shared by specific ligand series or scaffolds. RESULTS 28 31 ERα protein Classes of compounds in the ERα ligand library FIG 0 9 Structure evidence Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 17 25 E2‐bound protein_state Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 26 29 ERα protein Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 30 33 LBD structure_element Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 34 49 in complex with protein_state Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 53 58 NCOA2 protein Structure of the E2‐bound ERα LBD in complex with an NCOA2 peptide of (PDB 1GWR). FIG 26 29 ERα protein Structural details of the ERα LBD bound to the indicated ligands. FIG 30 33 LBD structure_element Structural details of the ERα LBD bound to the indicated ligands. FIG 34 42 bound to protein_state Structural details of the ERα LBD bound to the indicated ligands. FIG 7 9 E2 chemical Unlike E2 (PDB 1GWR), TAM is a direct modulator with a BSC that dislocates h12 to block the NCOA2‐binding site (PDB 3ERT). FIG 22 25 TAM chemical Unlike E2 (PDB 1GWR), TAM is a direct modulator with a BSC that dislocates h12 to block the NCOA2‐binding site (PDB 3ERT). FIG 75 78 h12 structure_element Unlike E2 (PDB 1GWR), TAM is a direct modulator with a BSC that dislocates h12 to block the NCOA2‐binding site (PDB 3ERT). FIG 92 110 NCOA2‐binding site site Unlike E2 (PDB 1GWR), TAM is a direct modulator with a BSC that dislocates h12 to block the NCOA2‐binding site (PDB 3ERT). FIG 0 4 OBHS chemical OBHS is an indirect modulator that dislocates the h11 C‐terminus to destabilize the h11–h12 interface (PDB 4ZN9). FIG 50 53 h11 structure_element OBHS is an indirect modulator that dislocates the h11 C‐terminus to destabilize the h11–h12 interface (PDB 4ZN9). FIG 84 101 h11–h12 interface site OBHS is an indirect modulator that dislocates the h11 C‐terminus to destabilize the h11–h12 interface (PDB 4ZN9). FIG 4 7 ERα protein The ERα ligand library contains 241 ligands representing 15 indirect modulator scaffolds, plus 4 direct modulator scaffolds. FIG 0 3 ERα protein ERα ligands induced a range of agonist activity profiles FIG 52 57 GREB1 protein To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 89 98 3×ERE‐Luc experimental_method To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 160 165 E‐Luc experimental_method To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 202 211 wild‐type protein_state To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 212 215 ERα protein To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 217 222 L‐Luc experimental_method To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 223 226 ERα protein To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 227 229 WT protein_state To this end, we compared the average ligand‐induced GREB1 mRNA levels in MCF‐7 cells and 3×ERE‐Luc reporter gene activity in Ishikawa endometrial cancer cells (E‐Luc) or in HepG2 cells transfected with wild‐type ERα (L‐Luc ERα‐WT) (Figs 3A and EV2A–C). RESULTS 95 103 OBHS‐ASC chemical Direct modulators showed significant differences in average activity between cell types except OBHS‐ASC analogs, which had similar low agonist activities in the three cell types. RESULTS 50 59 tamoxifen chemical While it was known that direct modulators such as tamoxifen drive cell‐specific signaling, these experiments reveal that indirect modulators also drive cell‐specific signaling, since eight of fourteen classes showed significant differences in average activity (Figs 3A and EV2A–C). RESULTS 36 39 ERα protein Ligand‐specific signaling underlies ERα‐mediated cell proliferation FIG 20 23 ERα protein (A) Ligand‐specific ERα activities in HepG2, Ishikawa and MCF‐7 cells. FIG 19 24 L‐Luc experimental_method The ligand‐induced L‐Luc ERα‐WT and E‐Luc activities and GREB1 mRNA levels are shown by scaffold (mean + SD). FIG 25 28 ERα protein The ligand‐induced L‐Luc ERα‐WT and E‐Luc activities and GREB1 mRNA levels are shown by scaffold (mean + SD). FIG 29 31 WT protein_state The ligand‐induced L‐Luc ERα‐WT and E‐Luc activities and GREB1 mRNA levels are shown by scaffold (mean + SD). FIG 36 41 E‐Luc experimental_method The ligand‐induced L‐Luc ERα‐WT and E‐Luc activities and GREB1 mRNA levels are shown by scaffold (mean + SD). FIG 57 62 GREB1 protein The ligand‐induced L‐Luc ERα‐WT and E‐Luc activities and GREB1 mRNA levels are shown by scaffold (mean + SD). FIG 11 25 class analysis experimental_method (B) Ligand class analysis of the L‐Luc ERα‐WT and ERα‐ΔAB activities in HepG2 cells. FIG 33 38 L‐Luc experimental_method (B) Ligand class analysis of the L‐Luc ERα‐WT and ERα‐ΔAB activities in HepG2 cells. FIG 39 42 ERα protein (B) Ligand class analysis of the L‐Luc ERα‐WT and ERα‐ΔAB activities in HepG2 cells. FIG 43 45 WT protein_state (B) Ligand class analysis of the L‐Luc ERα‐WT and ERα‐ΔAB activities in HepG2 cells. FIG 50 57 ERα‐ΔAB mutant (B) Ligand class analysis of the L‐Luc ERα‐WT and ERα‐ΔAB activities in HepG2 cells. FIG 27 29 AB structure_element Significant sensitivity to AB domain deletion was determined by Student's t‐test (n = number of ligands per scaffold in Fig 2). FIG 64 80 Student's t‐test experimental_method Significant sensitivity to AB domain deletion was determined by Student's t‐test (n = number of ligands per scaffold in Fig 2). FIG 0 35 Correlation and regression analyses experimental_method Correlation and regression analyses in a large test set. FIG 91 97 F‐test experimental_method In cluster 1, the first three comparisons (rows) showed significant positive correlations (F‐test for nonzero slope, P ≤ 0.05). FIG 117 118 P evidence In cluster 1, the first three comparisons (rows) showed significant positive correlations (F‐test for nonzero slope, P ≤ 0.05). FIG 182 190 deletion experimental_method In cluster 2, only one of these comparisons revealed a significant positive correlation, while none was significant in cluster 3. +, statistically significant correlations gained by deletion of the AB or F domains. FIG 198 200 AB structure_element In cluster 2, only one of these comparisons revealed a significant positive correlation, while none was significant in cluster 3. +, statistically significant correlations gained by deletion of the AB or F domains. FIG 204 205 F structure_element In cluster 2, only one of these comparisons revealed a significant positive correlation, while none was significant in cluster 3. +, statistically significant correlations gained by deletion of the AB or F domains. FIG 50 52 AB structure_element −, significant correlations lost upon deletion of AB or F domains. FIG 56 57 F structure_element −, significant correlations lost upon deletion of AB or F domains. FIG 0 9 Tamoxifen chemical Tamoxifen depends on AF‐1 for its cell‐specific activity (Sakamoto et al, 2002); therefore, we asked whether cell‐specific signaling observed here is due to a similar dependence on AF‐1 for activity (Fig EV1). RESULTS 21 25 AF‐1 structure_element Tamoxifen depends on AF‐1 for its cell‐specific activity (Sakamoto et al, 2002); therefore, we asked whether cell‐specific signaling observed here is due to a similar dependence on AF‐1 for activity (Fig EV1). RESULTS 181 185 AF‐1 structure_element Tamoxifen depends on AF‐1 for its cell‐specific activity (Sakamoto et al, 2002); therefore, we asked whether cell‐specific signaling observed here is due to a similar dependence on AF‐1 for activity (Fig EV1). RESULTS 35 59 average L‐Luc activities evidence To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 92 106 co‐transfected experimental_method To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 112 121 wild‐type protein_state To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 122 125 ERα protein To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 134 137 ERα protein To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 138 149 lacking the protein_state To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 150 152 AB structure_element To test this idea, we compared the average L‐Luc activities of each scaffold in HepG2 cells co‐transfected with wild‐type ERα or with ERα lacking the AB domain (Figs 1B and EV1). RESULTS 6 8 E2 chemical While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 24 29 L‐Luc experimental_method While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 30 33 ERα protein While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 34 36 WT protein_state While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 41 48 ERα‐ΔAB mutant While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 61 70 tamoxifen chemical While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 104 111 without protein_state While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 116 118 AB structure_element While E2 showed similar L‐Luc ERα‐WT and ERα‐ΔAB activities, tamoxifen showed complete loss of activity without the AB domain (Fig EV1B). RESULTS 0 11 Deletion of experimental_method Deletion of the AB domain significantly reduced the average L‐Luc activities of 14 scaffolds (Student's t‐test, P ≤ 0.05) (Fig 3B). RESULTS 16 18 AB structure_element Deletion of the AB domain significantly reduced the average L‐Luc activities of 14 scaffolds (Student's t‐test, P ≤ 0.05) (Fig 3B). RESULTS 52 76 average L‐Luc activities evidence Deletion of the AB domain significantly reduced the average L‐Luc activities of 14 scaffolds (Student's t‐test, P ≤ 0.05) (Fig 3B). RESULTS 94 110 Student's t‐test experimental_method Deletion of the AB domain significantly reduced the average L‐Luc activities of 14 scaffolds (Student's t‐test, P ≤ 0.05) (Fig 3B). RESULTS 112 113 P evidence Deletion of the AB domain significantly reduced the average L‐Luc activities of 14 scaffolds (Student's t‐test, P ≤ 0.05) (Fig 3B). RESULTS 7 11 AF‐1 structure_element These “AF‐1‐sensitive” activities were exhibited by both direct and indirect modulators, and were not limited to scaffolds that showed cell‐specific signaling (Fig 3A and B). RESULTS 22 26 AF‐1 structure_element Thus, the strength of AF‐1 signaling does not determine cell‐specific signaling. RESULTS 48 51 ERα protein Identifying cell‐specific signaling clusters in ERα ligand classes RESULTS 53 86 Pearson's correlation coefficient evidence For each ligand class or scaffold, we calculated the Pearson's correlation coefficient, r, for pairwise comparison of activity profiles in breast (GREB1), liver (L‐Luc), and endometrial cells (E‐Luc). RESULTS 88 89 r evidence For each ligand class or scaffold, we calculated the Pearson's correlation coefficient, r, for pairwise comparison of activity profiles in breast (GREB1), liver (L‐Luc), and endometrial cells (E‐Luc). RESULTS 147 152 GREB1 protein For each ligand class or scaffold, we calculated the Pearson's correlation coefficient, r, for pairwise comparison of activity profiles in breast (GREB1), liver (L‐Luc), and endometrial cells (E‐Luc). RESULTS 162 167 L‐Luc experimental_method For each ligand class or scaffold, we calculated the Pearson's correlation coefficient, r, for pairwise comparison of activity profiles in breast (GREB1), liver (L‐Luc), and endometrial cells (E‐Luc). RESULTS 193 198 E‐Luc experimental_method For each ligand class or scaffold, we calculated the Pearson's correlation coefficient, r, for pairwise comparison of activity profiles in breast (GREB1), liver (L‐Luc), and endometrial cells (E‐Luc). RESULTS 13 14 r evidence The value of r ranges from −1 to 1, and it defines the extent to which the data fit a straight line when compounds show similar agonist/antagonist activity profiles between cell types (Fig EV3A). RESULTS 23 51 coefficient of determination evidence We also calculated the coefficient of determination, r 2, which describes the percentage of variance in a dependent variable such as proliferation that can be predicted by an independent variable such as GREB1 expression. RESULTS 53 56 r 2 evidence We also calculated the coefficient of determination, r 2, which describes the percentage of variance in a dependent variable such as proliferation that can be predicted by an independent variable such as GREB1 expression. RESULTS 204 209 GREB1 protein We also calculated the coefficient of determination, r 2, which describes the percentage of variance in a dependent variable such as proliferation that can be predicted by an independent variable such as GREB1 expression. RESULTS 32 35 r 2 evidence We present both calculations as r 2 to readily compare signaling specificities using a heat map on which the red–yellow palette indicates significant positive correlations (P ≤ 0.05, F‐test for nonzero slope), while the blue palette denotes negative correlations (Fig 3C–F). RESULTS 173 174 P evidence We present both calculations as r 2 to readily compare signaling specificities using a heat map on which the red–yellow palette indicates significant positive correlations (P ≤ 0.05, F‐test for nonzero slope), while the blue palette denotes negative correlations (Fig 3C–F). RESULTS 183 189 F‐test experimental_method We present both calculations as r 2 to readily compare signaling specificities using a heat map on which the red–yellow palette indicates significant positive correlations (P ≤ 0.05, F‐test for nonzero slope), while the blue palette denotes negative correlations (Fig 3C–F). RESULTS 18 26 OBHS‐BSC chemical The side chain of OBHS‐BSC analogs induces cell‐specific signaling FIG 24 28 OBHS chemical Correlation analysis of OBHS versus OBHS‐BSC activity across cell types. FIG 36 44 OBHS‐BSC chemical Correlation analysis of OBHS versus OBHS‐BSC activity across cell types. FIG 24 29 L‐Luc experimental_method Correlation analysis of L‐Luc ERα‐ΔAB activity versus endogenous ERα activity of OBHS analogs. FIG 30 37 ERα‐ΔAB mutant Correlation analysis of L‐Luc ERα‐ΔAB activity versus endogenous ERα activity of OBHS analogs. FIG 65 68 ERα protein Correlation analysis of L‐Luc ERα‐ΔAB activity versus endogenous ERα activity of OBHS analogs. FIG 81 85 OBHS chemical Correlation analysis of L‐Luc ERα‐ΔAB activity versus endogenous ERα activity of OBHS analogs. FIG 14 19 L‐Luc experimental_method In panel (D), L‐Luc ERα‐WT activity from panel (B) is shown for comparison. FIG 20 23 ERα protein In panel (D), L‐Luc ERα‐WT activity from panel (B) is shown for comparison. FIG 24 26 WT protein_state In panel (D), L‐Luc ERα‐WT activity from panel (B) is shown for comparison. FIG 24 29 L‐Luc experimental_method Correlation analysis of L‐Luc ERα‐ΔF activity versus endogenous ERα activities of OBHS analogs. FIG 30 36 ERα‐ΔF mutant Correlation analysis of L‐Luc ERα‐ΔF activity versus endogenous ERα activities of OBHS analogs. FIG 64 67 ERα protein Correlation analysis of L‐Luc ERα‐ΔF activity versus endogenous ERα activities of OBHS analogs. FIG 82 86 OBHS chemical Correlation analysis of L‐Luc ERα‐ΔF activity versus endogenous ERα activities of OBHS analogs. FIG 56 63 NCOA2/3 protein Correlation analysis of MCF‐7 cell proliferation versus NCOA2/3 recruitment or GREB1 levels observed in response to (G) OBHS‐N and (H) OBHS‐BSC analogs. FIG 79 84 GREB1 protein Correlation analysis of MCF‐7 cell proliferation versus NCOA2/3 recruitment or GREB1 levels observed in response to (G) OBHS‐N and (H) OBHS‐BSC analogs. FIG 120 126 OBHS‐N chemical Correlation analysis of MCF‐7 cell proliferation versus NCOA2/3 recruitment or GREB1 levels observed in response to (G) OBHS‐N and (H) OBHS‐BSC analogs. FIG 135 143 OBHS‐BSC chemical Correlation analysis of MCF‐7 cell proliferation versus NCOA2/3 recruitment or GREB1 levels observed in response to (G) OBHS‐N and (H) OBHS‐BSC analogs. FIG 53 58 GREB1 protein Scaffolds in cluster 1 exhibited strongly correlated GREB1 levels, E‐Luc and L‐Luc activity profiles across the three cell types (Fig 3C lanes 1–4), suggesting these ligands use similar ERα signaling pathways in the breast, endometrial, and liver cell types. RESULTS 67 72 E‐Luc experimental_method Scaffolds in cluster 1 exhibited strongly correlated GREB1 levels, E‐Luc and L‐Luc activity profiles across the three cell types (Fig 3C lanes 1–4), suggesting these ligands use similar ERα signaling pathways in the breast, endometrial, and liver cell types. RESULTS 77 82 L‐Luc experimental_method Scaffolds in cluster 1 exhibited strongly correlated GREB1 levels, E‐Luc and L‐Luc activity profiles across the three cell types (Fig 3C lanes 1–4), suggesting these ligands use similar ERα signaling pathways in the breast, endometrial, and liver cell types. RESULTS 186 189 ERα protein Scaffolds in cluster 1 exhibited strongly correlated GREB1 levels, E‐Luc and L‐Luc activity profiles across the three cell types (Fig 3C lanes 1–4), suggesting these ligands use similar ERα signaling pathways in the breast, endometrial, and liver cell types. RESULTS 22 27 WAY‐C chemical This cluster includes WAY‐C, OBHS, OBHS‐N, and triaryl‐ethylene analogs, all of which are indirect modulators. RESULTS 29 33 OBHS chemical This cluster includes WAY‐C, OBHS, OBHS‐N, and triaryl‐ethylene analogs, all of which are indirect modulators. RESULTS 35 41 OBHS‐N chemical This cluster includes WAY‐C, OBHS, OBHS‐N, and triaryl‐ethylene analogs, all of which are indirect modulators. RESULTS 47 63 triaryl‐ethylene chemical This cluster includes WAY‐C, OBHS, OBHS‐N, and triaryl‐ethylene analogs, all of which are indirect modulators. RESULTS 56 70 cyclofenil‐ASC chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 75 84 WAY dimer chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 127 134 2,5‐DTP chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 136 143 3,4‐DTP chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 145 153 S‐OBHS‐2 chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 158 166 S‐OBHS‐3 chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 168 173 furan chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 179 184 WAY‐D chemical This cluster includes two classes of direct modulators (cyclofenil‐ASC and WAY dimer), and six classes of indirect modulators (2,5‐DTP, 3,4‐DTP, S‐OBHS‐2 and S‐OBHS‐3, furan, and WAY‐D). RESULTS 13 20 3,4‐DTP chemical For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 22 27 furan chemical For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 33 41 S‐OBHS‐2 chemical For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 70 75 GREB1 protein For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 87 92 E‐Luc experimental_method For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 101 106 L‐Luc experimental_method For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 107 110 ERα protein For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 111 113 WT protein_state For example, 3,4‐DTP, furan, and S‐OBHS‐2 drove positively correlated GREB1 levels and E‐Luc but not L‐Luc ERα‐WT activity (Fig 3C lanes 5–7). RESULTS 13 22 WAY dimer chemical In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 27 32 WAY‐D chemical In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 69 74 GREB1 protein In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 86 91 L‐Luc experimental_method In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 92 95 ERα protein In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 96 98 WT protein_state In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 107 112 E‐Luc experimental_method In contrast, WAY dimer and WAY‐D analogs drove positively correlated GREB1 levels and L‐Luc ERα‐WT but not E‐Luc activity (Fig 3C lanes 8 and 9). RESULTS 54 62 OBHS‐ASC chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 67 75 OBHS‐BSC chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 117 121 A‐CD chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 123 133 cyclofenil chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 135 143 3,4‐DTPD chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 145 150 imine chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 156 171 imidazopyridine chemical This cluster includes two direct modulator scaffolds (OBHS‐ASC and OBHS‐BSC), and five indirect modulator scaffolds (A‐CD, cyclofenil, 3,4‐DTPD, imine, and imidazopyridine). RESULTS 68 71 ERα protein These results suggest that addition of an extended side chain to an ERα ligand scaffold is sufficient to induce cell‐specific signaling, where the relative activity profiles of the individual ligands change between cell types. RESULTS 82 86 OBHS chemical This is demonstrated by directly comparing the signaling specificities of matched OBHS (indirect modulator, cluster 1) and OBHS‐BSC analogs (direct modulator, cluster 3), which differ only in the basic side chain (Fig 2E). RESULTS 123 131 OBHS‐BSC chemical This is demonstrated by directly comparing the signaling specificities of matched OBHS (indirect modulator, cluster 1) and OBHS‐BSC analogs (direct modulator, cluster 3), which differ only in the basic side chain (Fig 2E). RESULTS 18 22 OBHS chemical The activities of OBHS analogs were positively correlated across the three cell types, but the side chain of OBHS‐BSC analogs was sufficient to abolish these correlations (Figs 3C lanes 1 and 19, and EV3A–C). RESULTS 109 117 OBHS‐BSC chemical The activities of OBHS analogs were positively correlated across the three cell types, but the side chain of OBHS‐BSC analogs was sufficient to abolish these correlations (Figs 3C lanes 1 and 19, and EV3A–C). RESULTS 43 46 ERα protein Thus, examining the correlated patterns of ERα activity within each scaffold demonstrates that an extended side chain is not required for cell‐specific signaling. RESULTS 39 43 AF‐1 structure_element Modulation of signaling specificity by AF‐1 RESULTS 24 28 AF‐1 structure_element To evaluate the role of AF‐1 and the F domain in ERα signaling specificity, we compared activity of truncated ERα constructs in HepG2 liver cells with endogenous ERα activity in the other cell types. RESULTS 37 38 F structure_element To evaluate the role of AF‐1 and the F domain in ERα signaling specificity, we compared activity of truncated ERα constructs in HepG2 liver cells with endogenous ERα activity in the other cell types. RESULTS 49 52 ERα protein To evaluate the role of AF‐1 and the F domain in ERα signaling specificity, we compared activity of truncated ERα constructs in HepG2 liver cells with endogenous ERα activity in the other cell types. RESULTS 110 113 ERα protein To evaluate the role of AF‐1 and the F domain in ERα signaling specificity, we compared activity of truncated ERα constructs in HepG2 liver cells with endogenous ERα activity in the other cell types. RESULTS 162 165 ERα protein To evaluate the role of AF‐1 and the F domain in ERα signaling specificity, we compared activity of truncated ERα constructs in HepG2 liver cells with endogenous ERα activity in the other cell types. RESULTS 37 42 L‐Luc experimental_method The positive correlation between the L‐Luc and E‐Luc activities or GREB1 levels induced by scaffolds in cluster 1 was generally retained without the AB domain, or the F domain (Fig 3D lanes 1–4). RESULTS 47 52 E‐Luc experimental_method The positive correlation between the L‐Luc and E‐Luc activities or GREB1 levels induced by scaffolds in cluster 1 was generally retained without the AB domain, or the F domain (Fig 3D lanes 1–4). RESULTS 67 72 GREB1 protein The positive correlation between the L‐Luc and E‐Luc activities or GREB1 levels induced by scaffolds in cluster 1 was generally retained without the AB domain, or the F domain (Fig 3D lanes 1–4). RESULTS 149 151 AB structure_element The positive correlation between the L‐Luc and E‐Luc activities or GREB1 levels induced by scaffolds in cluster 1 was generally retained without the AB domain, or the F domain (Fig 3D lanes 1–4). RESULTS 167 168 F structure_element The positive correlation between the L‐Luc and E‐Luc activities or GREB1 levels induced by scaffolds in cluster 1 was generally retained without the AB domain, or the F domain (Fig 3D lanes 1–4). RESULTS 110 114 AF‐1 structure_element This demonstrates that the signaling specificities underlying these positive correlations are not modified by AF‐1. RESULTS 0 4 OBHS chemical OBHS analogs showed an average L‐Luc ERα‐ΔAB activity of 3.2% ± 3 (mean + SEM) relative to E2. RESULTS 31 36 L‐Luc experimental_method OBHS analogs showed an average L‐Luc ERα‐ΔAB activity of 3.2% ± 3 (mean + SEM) relative to E2. RESULTS 37 44 ERα‐ΔAB mutant OBHS analogs showed an average L‐Luc ERα‐ΔAB activity of 3.2% ± 3 (mean + SEM) relative to E2. RESULTS 91 93 E2 chemical OBHS analogs showed an average L‐Luc ERα‐ΔAB activity of 3.2% ± 3 (mean + SEM) relative to E2. RESULTS 62 67 L‐Luc experimental_method Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 68 75 ERα‐ΔAB mutant Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 122 127 E‐Luc experimental_method Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 141 146 GREB1 protein Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 206 210 AF‐2 structure_element Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 242 246 AF‐1 structure_element Despite this nearly complete lack of activity, the pattern of L‐Luc ERα‐ΔAB activity was still highly correlated with the E‐Luc activity and GREB1 expression (Fig EV3D and E), demonstrating that very small AF‐2 activities can be amplified by AF‐1 to produce robust signals. RESULTS 11 22 deletion of experimental_method Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 27 28 F structure_element Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 77 82 L‐Luc experimental_method Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 87 92 E‐Luc experimental_method Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 96 101 GREB1 protein Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 120 124 OBHS chemical Similarly, deletion of the F domain did not abolish correlations between the L‐Luc and E‐Luc or GREB1 levels induced by OBHS analogs (Fig EV3F). RESULTS 49 58 wild‐type protein_state These similar patterns of ligand activity in the wild‐type and deletion mutants suggest that AF‐1 and the F domain purely amplify the AF‐2 activities of ligands in cluster 1. RESULTS 72 79 mutants protein_state These similar patterns of ligand activity in the wild‐type and deletion mutants suggest that AF‐1 and the F domain purely amplify the AF‐2 activities of ligands in cluster 1. RESULTS 93 97 AF‐1 structure_element These similar patterns of ligand activity in the wild‐type and deletion mutants suggest that AF‐1 and the F domain purely amplify the AF‐2 activities of ligands in cluster 1. RESULTS 106 107 F structure_element These similar patterns of ligand activity in the wild‐type and deletion mutants suggest that AF‐1 and the F domain purely amplify the AF‐2 activities of ligands in cluster 1. RESULTS 134 138 AF‐2 structure_element These similar patterns of ligand activity in the wild‐type and deletion mutants suggest that AF‐1 and the F domain purely amplify the AF‐2 activities of ligands in cluster 1. RESULTS 13 17 AF‐1 structure_element In contrast, AF‐1 was a determinant of signaling specificity for scaffolds in cluster 2. RESULTS 0 11 Deletion of experimental_method Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 16 18 AB structure_element Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 22 23 F structure_element Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 100 107 2,5‐DTP chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 109 116 3,4‐DTP chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 118 126 S‐OBHS‐3 chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 128 133 WAY‐D chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 135 144 WAY dimer chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 150 164 cyclofenil‐ASC chemical Deletion of the AB or F domain altered correlations for six of the eight scaffolds in this cluster (2,5‐DTP, 3,4‐DTP, S‐OBHS‐3, WAY‐D, WAY dimer, and cyclofenil‐ASC) (Fig 3D lanes 5–12). RESULTS 61 83 deletion mutant assays experimental_method Comparing Fig 3C and D, the + and − signs indicate where the deletion mutant assays led to a gain or loss of statically significant correlation, respectively. RESULTS 20 24 AF‐1 structure_element Thus, in cluster 2, AF‐1 substantially modulated the specificity of ligands with cell‐specific activity (Fig 3D lanes 5–12). RESULTS 60 64 AF‐1 structure_element For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 183 194 deletion of experimental_method For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 199 201 AB structure_element For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 205 206 F structure_element For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 268 272 A‐CD chemical For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 277 285 OBHS‐ASC chemical For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 301 312 deletion of experimental_method For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 317 319 AB structure_element For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 330 331 F structure_element For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 373 378 E‐Luc experimental_method For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 395 400 GREB1 protein For ligands in cluster 3, we could not eliminate a role for AF‐1 in determining signaling specificity, since this cluster lacked positively correlated activity profiles (Fig 3C), and deletion of the AB or F domain rarely induced such correlations (Fig 3D), except for A‐CD and OBHS‐ASC analogs, where deletion of the AB domain or F domain led to positive correlations with E‐Luc activity and/or GREB1 levels (Fig 3D lanes 13 and 18). RESULTS 35 39 AF‐1 structure_element Thus, ligands in cluster 2 rely on AF‐1 for both activity (Fig 3B) and signaling specificity (Fig 3D). RESULTS 27 32 GREB1 protein Ligand‐specific control of GREB1 expression RESULTS 65 68 ERα protein To determine whether ligand classes control expression of native ERα target genes through the canonical linear signaling pathway, we performed pairwise linear regression analyses using ERα–NCOA1/2/3 interactions in M2H assay as independent predictors of GREB1 expression (the dependent variable) (Figs EV1 and EV2A, F–H). RESULTS 143 178 pairwise linear regression analyses experimental_method To determine whether ligand classes control expression of native ERα target genes through the canonical linear signaling pathway, we performed pairwise linear regression analyses using ERα–NCOA1/2/3 interactions in M2H assay as independent predictors of GREB1 expression (the dependent variable) (Figs EV1 and EV2A, F–H). RESULTS 185 198 ERα–NCOA1/2/3 complex_assembly To determine whether ligand classes control expression of native ERα target genes through the canonical linear signaling pathway, we performed pairwise linear regression analyses using ERα–NCOA1/2/3 interactions in M2H assay as independent predictors of GREB1 expression (the dependent variable) (Figs EV1 and EV2A, F–H). RESULTS 215 224 M2H assay experimental_method To determine whether ligand classes control expression of native ERα target genes through the canonical linear signaling pathway, we performed pairwise linear regression analyses using ERα–NCOA1/2/3 interactions in M2H assay as independent predictors of GREB1 expression (the dependent variable) (Figs EV1 and EV2A, F–H). RESULTS 254 259 GREB1 protein To determine whether ligand classes control expression of native ERα target genes through the canonical linear signaling pathway, we performed pairwise linear regression analyses using ERα–NCOA1/2/3 interactions in M2H assay as independent predictors of GREB1 expression (the dependent variable) (Figs EV1 and EV2A, F–H). RESULTS 33 38 NCOA1 protein In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 43 48 NCOA2 protein In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 65 70 WAY‐C chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 84 100 triaryl‐ethylene chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 102 108 OBHS‐N chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 114 118 OBHS chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 137 142 NCOA3 protein In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 144 150 OBHS‐N chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 194 198 OBHS chemical In cluster 1, the recruitment of NCOA1 and NCOA2 was highest for WAY‐C, followed by triaryl‐ethylene, OBHS‐N, and OBHS series, while for NCOA3, OBHS‐N compounds induced the most recruitment and OBHS ligands were inverse agonists (Fig EV2F–H). RESULTS 25 30 GREB1 protein The average induction of GREB1 by cluster 1 ligands showed greater variance, with a range between ~25 and ~75% for OBHS and a range from full agonist to inverse agonist for the others in cluster 1 (Fig EV2A). RESULTS 115 119 OBHS chemical The average induction of GREB1 by cluster 1 ligands showed greater variance, with a range between ~25 and ~75% for OBHS and a range from full agonist to inverse agonist for the others in cluster 1 (Fig EV2A). RESULTS 0 5 GREB1 protein GREB1 levels induced by OBHS analogs were determined by recruitment of NCOA1 but not NCOA2/3 (Fig 3E lane 1), suggesting that there may be alternate or preferential use of these coactivators by different classes. RESULTS 24 28 OBHS chemical GREB1 levels induced by OBHS analogs were determined by recruitment of NCOA1 but not NCOA2/3 (Fig 3E lane 1), suggesting that there may be alternate or preferential use of these coactivators by different classes. RESULTS 71 76 NCOA1 protein GREB1 levels induced by OBHS analogs were determined by recruitment of NCOA1 but not NCOA2/3 (Fig 3E lane 1), suggesting that there may be alternate or preferential use of these coactivators by different classes. RESULTS 85 92 NCOA2/3 protein GREB1 levels induced by OBHS analogs were determined by recruitment of NCOA1 but not NCOA2/3 (Fig 3E lane 1), suggesting that there may be alternate or preferential use of these coactivators by different classes. RESULTS 23 32 NCOA1/2/3 protein However, in cluster 1, NCOA1/2/3 recruitment generally predicted GREB1 levels (Fig 3E lanes 1–4), consistent with the canonical signaling model (Fig 1D). RESULTS 65 70 GREB1 protein However, in cluster 1, NCOA1/2/3 recruitment generally predicted GREB1 levels (Fig 3E lanes 1–4), consistent with the canonical signaling model (Fig 1D). RESULTS 22 27 GREB1 protein For clusters 2 and 3, GREB1 activity was generally not predicted by NCOA1/2/3 recruitment. RESULTS 68 77 NCOA1/2/3 protein For clusters 2 and 3, GREB1 activity was generally not predicted by NCOA1/2/3 recruitment. RESULTS 29 38 NCOA1/2/3 protein Direct modulators showed low NCOA1/2/3 recruitment (Fig EV2F–H), but only OBHS‐ASC analogs had NCOA2 recruitment profiles that predicted a full range of effects on GREB1 levels (Figs 3E lanes 9, 11, 18–19, and EV2A). RESULTS 74 82 OBHS‐ASC chemical Direct modulators showed low NCOA1/2/3 recruitment (Fig EV2F–H), but only OBHS‐ASC analogs had NCOA2 recruitment profiles that predicted a full range of effects on GREB1 levels (Figs 3E lanes 9, 11, 18–19, and EV2A). RESULTS 95 100 NCOA2 protein Direct modulators showed low NCOA1/2/3 recruitment (Fig EV2F–H), but only OBHS‐ASC analogs had NCOA2 recruitment profiles that predicted a full range of effects on GREB1 levels (Figs 3E lanes 9, 11, 18–19, and EV2A). RESULTS 164 169 GREB1 protein Direct modulators showed low NCOA1/2/3 recruitment (Fig EV2F–H), but only OBHS‐ASC analogs had NCOA2 recruitment profiles that predicted a full range of effects on GREB1 levels (Figs 3E lanes 9, 11, 18–19, and EV2A). RESULTS 55 64 NCOA1/2/3 protein The indirect modulators in clusters 2 and 3 stimulated NCOA1/2/3 recruitment and GREB1 expression with substantial variance (Figs 3A and EV2F–H). RESULTS 81 86 GREB1 protein The indirect modulators in clusters 2 and 3 stimulated NCOA1/2/3 recruitment and GREB1 expression with substantial variance (Figs 3A and EV2F–H). RESULTS 24 29 GREB1 protein However, ligand‐induced GREB1 levels were generally not determined by NCOA1/2/3 recruitment (Fig 3E lanes 5–19), consistent with an alternate causality model (Fig 1E). RESULTS 70 79 NCOA1/2/3 protein However, ligand‐induced GREB1 levels were generally not determined by NCOA1/2/3 recruitment (Fig 3E lanes 5–19), consistent with an alternate causality model (Fig 1E). RESULTS 64 72 S‐OBHS‐3 chemical Out of 11 indirect modulator series in cluster 2 or 3, only the S‐OBHS‐3 class had NCOA1/2/3 recruitment profiles that predicted GREB1 levels (Fig 3E lane 12). RESULTS 83 92 NCOA1/2/3 protein Out of 11 indirect modulator series in cluster 2 or 3, only the S‐OBHS‐3 class had NCOA1/2/3 recruitment profiles that predicted GREB1 levels (Fig 3E lane 12). RESULTS 129 134 GREB1 protein Out of 11 indirect modulator series in cluster 2 or 3, only the S‐OBHS‐3 class had NCOA1/2/3 recruitment profiles that predicted GREB1 levels (Fig 3E lane 12). RESULTS 87 92 GREB1 protein These results suggest that compounds that show cell‐specific signaling do not activate GREB1, or use coactivators other than NCOA1/2/3 to control GREB1 expression (Fig 1E). RESULTS 125 134 NCOA1/2/3 protein These results suggest that compounds that show cell‐specific signaling do not activate GREB1, or use coactivators other than NCOA1/2/3 to control GREB1 expression (Fig 1E). RESULTS 146 151 GREB1 protein These results suggest that compounds that show cell‐specific signaling do not activate GREB1, or use coactivators other than NCOA1/2/3 to control GREB1 expression (Fig 1E). RESULTS 103 129 linear regression analyses experimental_method To determine mechanisms for ligand‐dependent control of breast cancer cell proliferation, we performed linear regression analyses across the 19 scaffolds using MCF‐7 cell proliferation as the dependent variable, and the other activities as independent variables (Fig 3F). RESULTS 14 19 E‐Luc experimental_method In cluster 1, E‐Luc and L‐Luc activities, NCOA1/2/3 recruitment, and GREB1 levels generally predicted the proliferative response (Fig 3F lanes 2–4). RESULTS 24 29 L‐Luc experimental_method In cluster 1, E‐Luc and L‐Luc activities, NCOA1/2/3 recruitment, and GREB1 levels generally predicted the proliferative response (Fig 3F lanes 2–4). RESULTS 42 51 NCOA1/2/3 protein In cluster 1, E‐Luc and L‐Luc activities, NCOA1/2/3 recruitment, and GREB1 levels generally predicted the proliferative response (Fig 3F lanes 2–4). RESULTS 69 74 GREB1 protein In cluster 1, E‐Luc and L‐Luc activities, NCOA1/2/3 recruitment, and GREB1 levels generally predicted the proliferative response (Fig 3F lanes 2–4). RESULTS 9 15 OBHS‐N chemical With the OBHS‐N compounds, NCOA3 and GREB1 showed near perfect prediction of proliferation (Fig EV3G), with unexplained variance similar to the noise in the assays. RESULTS 27 32 NCOA3 protein With the OBHS‐N compounds, NCOA3 and GREB1 showed near perfect prediction of proliferation (Fig EV3G), with unexplained variance similar to the noise in the assays. RESULTS 37 42 GREB1 protein With the OBHS‐N compounds, NCOA3 and GREB1 showed near perfect prediction of proliferation (Fig EV3G), with unexplained variance similar to the noise in the assays. RESULTS 39 43 OBHS chemical The lack of significant predictors for OBHS analogs (Fig 3F lane 1) reflects their small range of proliferative effects on MCF‐7 cells (Fig EV2I). RESULTS 34 39 GREB1 protein The significant correlations with GREB1 expression and NCOA1/2/3 recruitment observed in this cluster are consistent with the canonical signaling model (Fig 1D), where NCOA1/2/3 recruitment determines GREB1 expression, which then drives proliferation. RESULTS 55 64 NCOA1/2/3 protein The significant correlations with GREB1 expression and NCOA1/2/3 recruitment observed in this cluster are consistent with the canonical signaling model (Fig 1D), where NCOA1/2/3 recruitment determines GREB1 expression, which then drives proliferation. RESULTS 168 177 NCOA1/2/3 protein The significant correlations with GREB1 expression and NCOA1/2/3 recruitment observed in this cluster are consistent with the canonical signaling model (Fig 1D), where NCOA1/2/3 recruitment determines GREB1 expression, which then drives proliferation. RESULTS 201 206 GREB1 protein The significant correlations with GREB1 expression and NCOA1/2/3 recruitment observed in this cluster are consistent with the canonical signaling model (Fig 1D), where NCOA1/2/3 recruitment determines GREB1 expression, which then drives proliferation. RESULTS 90 99 NCOA1/2/3 protein Despite this phenotypic variance, proliferation was not generally predicted by correlated NCOA1/2/3 recruitment and GREB1 induction (Figs 3F lanes 5–19, and EV3H). RESULTS 116 121 GREB1 protein Despite this phenotypic variance, proliferation was not generally predicted by correlated NCOA1/2/3 recruitment and GREB1 induction (Figs 3F lanes 5–19, and EV3H). RESULTS 48 55 2,5‐DTP chemical Out of 15 ligand series in these clusters, only 2,5‐DTP analogs induced a proliferative response that was predicted by GREB1 levels, which were not determined by NCOA1/2/3 recruitment (Fig 3E and F lane 10). RESULTS 119 124 GREB1 protein Out of 15 ligand series in these clusters, only 2,5‐DTP analogs induced a proliferative response that was predicted by GREB1 levels, which were not determined by NCOA1/2/3 recruitment (Fig 3E and F lane 10). RESULTS 162 171 NCOA1/2/3 protein Out of 15 ligand series in these clusters, only 2,5‐DTP analogs induced a proliferative response that was predicted by GREB1 levels, which were not determined by NCOA1/2/3 recruitment (Fig 3E and F lane 10). RESULTS 0 7 3,4‐DTP chemical 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 9 19 cyclofenil chemical 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 21 29 3,4‐DTPD chemical 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 35 50 imidazopyridine chemical 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 63 70 NCOA1/3 protein 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 156 161 GREB1 protein 3,4‐DTP, cyclofenil, 3,4‐DTPD, and imidazopyridine analogs had NCOA1/3 recruitment profiles that predicted their proliferative effects, without determining GREB1 levels (Fig 3E and F, lanes 5 and 14–16). RESULTS 11 19 S‐OBHS‐3 chemical Similarly, S‐OBHS‐3, cyclofenil‐ASC, and OBHS‐ASC had positively correlated NCOA1/2/3 recruitment and GREB1 levels, but none of these activities determined their proliferative effects (Fig 3E and F lanes 11–12 and 18). RESULTS 21 35 cyclofenil‐ASC chemical Similarly, S‐OBHS‐3, cyclofenil‐ASC, and OBHS‐ASC had positively correlated NCOA1/2/3 recruitment and GREB1 levels, but none of these activities determined their proliferative effects (Fig 3E and F lanes 11–12 and 18). RESULTS 41 49 OBHS‐ASC chemical Similarly, S‐OBHS‐3, cyclofenil‐ASC, and OBHS‐ASC had positively correlated NCOA1/2/3 recruitment and GREB1 levels, but none of these activities determined their proliferative effects (Fig 3E and F lanes 11–12 and 18). RESULTS 76 85 NCOA1/2/3 protein Similarly, S‐OBHS‐3, cyclofenil‐ASC, and OBHS‐ASC had positively correlated NCOA1/2/3 recruitment and GREB1 levels, but none of these activities determined their proliferative effects (Fig 3E and F lanes 11–12 and 18). RESULTS 102 107 GREB1 protein Similarly, S‐OBHS‐3, cyclofenil‐ASC, and OBHS‐ASC had positively correlated NCOA1/2/3 recruitment and GREB1 levels, but none of these activities determined their proliferative effects (Fig 3E and F lanes 11–12 and 18). RESULTS 47 50 ERα protein For ligands that show cell‐specific signaling, ERα‐mediated recruitment of other coregulators and activation of other target genes likely determine their proliferative effects on MCF‐7 cells. RESULTS 0 5 NCOA3 protein NCOA3 occupancy at GREB1 did not predict the proliferative response RESULTS 19 24 GREB1 protein NCOA3 occupancy at GREB1 did not predict the proliferative response RESULTS 137 199 chromatin immunoprecipitation (ChIP)‐based quantitative assay, experimental_method We also questioned whether promoter occupancy by coactivators is statistically robust and reproducible for ligand class analysis using a chromatin immunoprecipitation (ChIP)‐based quantitative assay, and whether it has a better predictive power than the M2H assay. RESULTS 254 263 M2H assay experimental_method We also questioned whether promoter occupancy by coactivators is statistically robust and reproducible for ligand class analysis using a chromatin immunoprecipitation (ChIP)‐based quantitative assay, and whether it has a better predictive power than the M2H assay. RESULTS 0 3 ERα protein ERα and NCOA3 cycle on and off the GREB1 promoter (Nwachukwu et al, 2014). RESULTS 8 13 NCOA3 protein ERα and NCOA3 cycle on and off the GREB1 promoter (Nwachukwu et al, 2014). RESULTS 35 40 GREB1 protein ERα and NCOA3 cycle on and off the GREB1 promoter (Nwachukwu et al, 2014). RESULTS 32 49 time‐course study experimental_method Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 66 68 E2 chemical Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 77 82 WAY‐C chemical Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 91 102 AAPII‐151‐4 chemical Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 127 132 NCOA3 protein Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 140 145 GREB1 protein Therefore, we first performed a time‐course study, and found that E2 and the WAY‐C analog, AAPII‐151‐4, induced recruitment of NCOA3 to the GREB1 promoter in a temporal cycle that peaked after 45 min in MCF‐7 cells (Fig 4A). RESULTS 26 31 WAY‐C chemical At this time point, other WAY‐C analogs also induced recruitment of NCOA3 at this site to varying degrees (Fig 4B). RESULTS 68 73 NCOA3 protein At this time point, other WAY‐C analogs also induced recruitment of NCOA3 at this site to varying degrees (Fig 4B). RESULTS 4 6 Z’ evidence The Z’ for this assay was 0.6, showing statistical robustness (see Materials and Methods). RESULTS 116 119 r 2 evidence We prepared biological replicates with different cell passage numbers and separately prepared samples, which showed r 2 of 0.81, demonstrating high reproducibility (Fig 4C). RESULTS 1 6 NCOA3 protein NCOA3 occupancy at GREB1 is statistically robust but does not predict transcriptional activity FIG 20 25 GREB1 protein NCOA3 occupancy at GREB1 is statistically robust but does not predict transcriptional activity FIG 0 18 Kinetic ChIP assay experimental_method Kinetic ChIP assay examining recruitment of NCOA3 to the GREB1 gene in MCF‐7 cells stimulated with E2 or the indicated WAY‐C analog. FIG 44 49 NCOA3 protein Kinetic ChIP assay examining recruitment of NCOA3 to the GREB1 gene in MCF‐7 cells stimulated with E2 or the indicated WAY‐C analog. FIG 57 62 GREB1 protein Kinetic ChIP assay examining recruitment of NCOA3 to the GREB1 gene in MCF‐7 cells stimulated with E2 or the indicated WAY‐C analog. FIG 99 101 E2 chemical Kinetic ChIP assay examining recruitment of NCOA3 to the GREB1 gene in MCF‐7 cells stimulated with E2 or the indicated WAY‐C analog. FIG 119 124 WAY‐C chemical Kinetic ChIP assay examining recruitment of NCOA3 to the GREB1 gene in MCF‐7 cells stimulated with E2 or the indicated WAY‐C analog. FIG 0 5 NCOA3 protein NCOA3 occupancy at GREB1 was compared by ChIP assay 45 min after stimulation with vehicle, E2, or the WAY‐C analogs. FIG 19 24 GREB1 protein NCOA3 occupancy at GREB1 was compared by ChIP assay 45 min after stimulation with vehicle, E2, or the WAY‐C analogs. FIG 41 51 ChIP assay experimental_method NCOA3 occupancy at GREB1 was compared by ChIP assay 45 min after stimulation with vehicle, E2, or the WAY‐C analogs. FIG 91 93 E2 chemical NCOA3 occupancy at GREB1 was compared by ChIP assay 45 min after stimulation with vehicle, E2, or the WAY‐C analogs. FIG 102 107 WAY‐C chemical NCOA3 occupancy at GREB1 was compared by ChIP assay 45 min after stimulation with vehicle, E2, or the WAY‐C analogs. FIG 100 107 Z‐score evidence In panel (B), the average recruitment of two biological replicates are shown as mean + SEM, and the Z‐score is indicated. FIG 14 34 correlation analysis experimental_method In panel (C), correlation analysis was performed for two biological replicates. FIG 0 26 Linear regression analyses experimental_method Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 52 57 NCOA3 protein Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 83 87 ChIP experimental_method Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 91 94 M2H experimental_method Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 135 140 WAY‐C chemical Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 185 191 F‐test experimental_method Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 211 218 P‐value evidence Linear regression analyses comparing the ability of NCOA3 recruitment, measured by ChIP or M2H, to predict other agonist activities of WAY‐C analogs. *Significant positive correlation (F‐test for nonzero slope, P‐value). FIG 4 13 M2H assay experimental_method The M2H assay for NCOA3 recruitment broadly correlated with the other assays, and was predictive for GREB1 expression and cell proliferation (Fig 3E). RESULTS 18 23 NCOA3 protein The M2H assay for NCOA3 recruitment broadly correlated with the other assays, and was predictive for GREB1 expression and cell proliferation (Fig 3E). RESULTS 101 106 GREB1 protein The M2H assay for NCOA3 recruitment broadly correlated with the other assays, and was predictive for GREB1 expression and cell proliferation (Fig 3E). RESULTS 13 24 ChIP assays experimental_method However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 29 34 WAY‐C chemical However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 58 63 NCOA3 protein However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 71 76 GREB1 protein However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 126 131 WAY‐C chemical However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 202 213 ChIP assays experimental_method However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 218 223 NCOA3 protein However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 240 249 M2H assay experimental_method However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 290 293 r 2 evidence However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 305 306 P evidence However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 315 321 F‐test experimental_method However, the ChIP assays for WAY‐C‐induced recruitment of NCOA3 to the GREB1 promoter did not correlate with any of the other WAY‐C activity profiles (Fig 4D), although the positive correlation between ChIP assays and NCOA3 recruitment via M2H assay showed a trend toward significance with r 2 = 0.36 and P = 0.09 (F‐test for nonzero slope). RESULTS 21 46 coactivator‐binding assay experimental_method Thus, the simplified coactivator‐binding assay showed much greater predictive power than the ChIP assay for ligand‐specific effects on GREB1 expression and cell proliferation. RESULTS 93 103 ChIP assay experimental_method Thus, the simplified coactivator‐binding assay showed much greater predictive power than the ChIP assay for ligand‐specific effects on GREB1 expression and cell proliferation. RESULTS 135 140 GREB1 protein Thus, the simplified coactivator‐binding assay showed much greater predictive power than the ChIP assay for ligand‐specific effects on GREB1 expression and cell proliferation. RESULTS 0 3 ERβ protein ERβ activity is not an independent predictor of cell‐specific activity RESULTS 110 113 ERβ protein One difference between MCF‐7 breast cancer cells and Ishikawa endometrial cancer cells is the contribution of ERβ to estrogenic response, as Ishikawa cells may express ERβ (Bhat & Pezzuto, 2001). RESULTS 168 171 ERβ protein One difference between MCF‐7 breast cancer cells and Ishikawa endometrial cancer cells is the contribution of ERβ to estrogenic response, as Ishikawa cells may express ERβ (Bhat & Pezzuto, 2001). RESULTS 5 18 overexpressed experimental_method When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 35 38 ERβ protein When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 46 48 E2 chemical When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 88 91 ERα protein When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 167 170 ERβ protein When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 198 203 E‐Luc experimental_method When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 270 275 E‐Luc experimental_method When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 280 285 L‐Luc experimental_method When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 286 289 ERα protein When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 290 292 WT protein_state When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 307 312 GREB1 protein When overexpressed in MCF‐7 cells, ERβ alters E2‐induced expression of only a subset of ERα‐target genes (Wu et al, 2011), raising the possibility that ligand‐induced ERβ activity may contribute to E‐Luc activities, and thus underlie the lack of correlation between the E‐Luc and L‐Luc ERα‐WT activities or GREB1 levels induced by cell‐specific modulators in cluster 2 and cluster 3 (Fig 3C). RESULTS 37 42 L‐Luc experimental_method To test this idea, we determined the L‐Luc ERβ activity profiles of the ligands (Fig EV1). RESULTS 59 63 OBHS chemical All direct modulator and two indirect modulator scaffolds (OBHS and S‐OBHS‐3) lacked ERβ agonist activity. RESULTS 68 76 S‐OBHS‐3 chemical All direct modulator and two indirect modulator scaffolds (OBHS and S‐OBHS‐3) lacked ERβ agonist activity. RESULTS 20 25 L‐Luc experimental_method For most scaffolds, L‐Luc ERβ and E‐Luc activities were not correlated, except for 2,5‐DTP and cyclofenil analogs, which showed moderate but significant correlations (Fig EV4A). RESULTS 34 39 E‐Luc experimental_method For most scaffolds, L‐Luc ERβ and E‐Luc activities were not correlated, except for 2,5‐DTP and cyclofenil analogs, which showed moderate but significant correlations (Fig EV4A). RESULTS 83 90 2,5‐DTP chemical For most scaffolds, L‐Luc ERβ and E‐Luc activities were not correlated, except for 2,5‐DTP and cyclofenil analogs, which showed moderate but significant correlations (Fig EV4A). RESULTS 95 105 cyclofenil chemical For most scaffolds, L‐Luc ERβ and E‐Luc activities were not correlated, except for 2,5‐DTP and cyclofenil analogs, which showed moderate but significant correlations (Fig EV4A). RESULTS 18 23 E‐Luc experimental_method Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 43 50 2,5‐DTP chemical Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 55 65 cyclofenil chemical Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 105 110 L‐Luc experimental_method Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 111 114 ERα protein Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 115 117 WT protein_state Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 123 128 L‐Luc experimental_method Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 129 132 ERβ protein Nevertheless, the E‐Luc activities of both 2,5‐DTP and cyclofenil analogs were better predicted by their L‐Luc ERα‐WT than L‐Luc ERβ activities (Fig EV4A and B). RESULTS 0 3 ERβ protein ERβ activity is not an independent predictor of E‐Luc activity FIG 48 53 E‐Luc experimental_method ERβ activity is not an independent predictor of E‐Luc activity FIG 0 3 ERβ protein ERβ activity in HepG2 cells rarely correlates with E‐Luc activity. FIG 51 56 E‐Luc experimental_method ERβ activity in HepG2 cells rarely correlates with E‐Luc activity. FIG 0 3 ERα protein ERα activity of 2,5‐DTP and cyclofenil analogs correlates with E‐Luc activity. FIG 16 23 2,5‐DTP chemical ERα activity of 2,5‐DTP and cyclofenil analogs correlates with E‐Luc activity. FIG 28 38 cyclofenil chemical ERα activity of 2,5‐DTP and cyclofenil analogs correlates with E‐Luc activity. FIG 63 68 E‐Luc experimental_method ERα activity of 2,5‐DTP and cyclofenil analogs correlates with E‐Luc activity. FIG 31 39 P values evidence Data information: The r 2 and P values for the indicated correlations are shown in both panels. *Significant positive correlation (F‐test for nonzero slope, P‐value) FIG 132 138 F‐test experimental_method Data information: The r 2 and P values for the indicated correlations are shown in both panels. *Significant positive correlation (F‐test for nonzero slope, P‐value) FIG 158 165 P‐value evidence Data information: The r 2 and P values for the indicated correlations are shown in both panels. *Significant positive correlation (F‐test for nonzero slope, P‐value) FIG 24 39 crystallization experimental_method To overcome barriers to crystallization of ERα LBD complexes, we developed a conformation‐trapping X‐ray crystallography approach using the ERα‐Y537S mutation (Nettles et al, 2008; Bruning et al, 2010; Srinivasan et al, 2013). RESULTS 43 46 ERα protein To overcome barriers to crystallization of ERα LBD complexes, we developed a conformation‐trapping X‐ray crystallography approach using the ERα‐Y537S mutation (Nettles et al, 2008; Bruning et al, 2010; Srinivasan et al, 2013). RESULTS 47 50 LBD structure_element To overcome barriers to crystallization of ERα LBD complexes, we developed a conformation‐trapping X‐ray crystallography approach using the ERα‐Y537S mutation (Nettles et al, 2008; Bruning et al, 2010; Srinivasan et al, 2013). RESULTS 77 120 conformation‐trapping X‐ray crystallography experimental_method To overcome barriers to crystallization of ERα LBD complexes, we developed a conformation‐trapping X‐ray crystallography approach using the ERα‐Y537S mutation (Nettles et al, 2008; Bruning et al, 2010; Srinivasan et al, 2013). RESULTS 140 149 ERα‐Y537S mutant To overcome barriers to crystallization of ERα LBD complexes, we developed a conformation‐trapping X‐ray crystallography approach using the ERα‐Y537S mutation (Nettles et al, 2008; Bruning et al, 2010; Srinivasan et al, 2013). RESULTS 38 44 solved experimental_method To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 49 58 structure evidence To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 66 75 ERα‐Y537S mutant To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 76 79 LBD structure_element To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 80 95 in complex with protein_state To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 96 114 diethylstilbestrol chemical To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 116 119 DES chemical To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 153 162 wild‐type protein_state To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 167 176 ERα‐Y537S mutant To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 177 181 LBDs structure_element To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 241 244 h12 structure_element To further validate this approach, we solved the structure of the ERα‐Y537S LBD in complex with diethylstilbestrol (DES), which bound identically in the wild‐type and ERα‐Y537S LBDs, demonstrating again that this surface mutation stabilizes h12 dynamics to facilitate crystallization without changing ligand binding (Appendix Fig S1A and B) (Nettles et al, 2008; Bruning et al, 2010; Delfosse et al, 2012). RESULTS 24 30 solved experimental_method Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 34 37 ERα protein Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 38 41 LBD structure_element Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 42 52 structures evidence Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 60 79 active conformation protein_state Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 84 100 bound to ligands protein_state Using this approach, we solved 76 ERα LBD structures in the active conformation and bound to ligands studied here (Appendix Fig S1C). RESULTS 16 26 structures evidence Eleven of these structures have been published, while 65 are new, including the DES‐bound ERα‐Y537S LBD. RESULTS 80 89 DES‐bound protein_state Eleven of these structures have been published, while 65 are new, including the DES‐bound ERα‐Y537S LBD. RESULTS 90 99 ERα‐Y537S mutant Eleven of these structures have been published, while 65 are new, including the DES‐bound ERα‐Y537S LBD. RESULTS 100 103 LBD structure_element Eleven of these structures have been published, while 65 are new, including the DES‐bound ERα‐Y537S LBD. RESULTS 27 37 structures evidence We present 57 of these new structures here (Dataset EV2), while the remaining eight new structures bound to OBHS‐N analogs will be published elsewhere (S. Srinivasan et al, in preparation). RESULTS 88 98 structures evidence We present 57 of these new structures here (Dataset EV2), while the remaining eight new structures bound to OBHS‐N analogs will be published elsewhere (S. Srinivasan et al, in preparation). RESULTS 99 107 bound to protein_state We present 57 of these new structures here (Dataset EV2), while the remaining eight new structures bound to OBHS‐N analogs will be published elsewhere (S. Srinivasan et al, in preparation). RESULTS 108 114 OBHS‐N chemical We present 57 of these new structures here (Dataset EV2), while the remaining eight new structures bound to OBHS‐N analogs will be published elsewhere (S. Srinivasan et al, in preparation). RESULTS 31 41 structures evidence Examining many closely related structures allows us to visualize subtle structural differences, in effect using X‐ray crystallography as a systems biology tool. RESULTS 112 133 X‐ray crystallography experimental_method Examining many closely related structures allows us to visualize subtle structural differences, in effect using X‐ray crystallography as a systems biology tool. RESULTS 165 168 h12 structure_element The indirect modulator scaffolds in cluster 1 did not show cell‐specific signaling (Fig 3C), but shared common structural perturbations that we designed to modulate h12 dynamics. RESULTS 22 26 OBHS chemical Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 27 36 structure evidence Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 42 46 OBHS chemical Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 48 54 OBHS‐N chemical Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 60 76 triaryl‐ethylene chemical Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 106 109 h11 structure_element Based on our original OBHS structure, the OBHS, OBHS‐N, and triaryl‐ethylene compounds were modified with h11‐directed pendant groups (Zheng et al, 2012; Zhu et al, 2012; Liao et al, 2014). RESULTS 0 11 Superposing experimental_method Superposing the LBDs based on the class of bound ligands provides an ensemble view of the structural variance and clarifies what part of the ligand‐binding pocket is differentially perturbed or targeted. RESULTS 16 20 LBDs structure_element Superposing the LBDs based on the class of bound ligands provides an ensemble view of the structural variance and clarifies what part of the ligand‐binding pocket is differentially perturbed or targeted. RESULTS 141 162 ligand‐binding pocket site Superposing the LBDs based on the class of bound ligands provides an ensemble view of the structural variance and clarifies what part of the ligand‐binding pocket is differentially perturbed or targeted. RESULTS 7 17 structures evidence The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 29 33 OBHS chemical The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 35 41 OBHS‐N chemical The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 46 62 triaryl‐ethylene chemical The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 180 183 LBD structure_element The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 206 209 h11 structure_element The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 258 261 h12 structure_element The 24 structures containing OBHS, OBHS‐N, or triaryl‐ethylene analogs showed structural diversity in the same part of the scaffolds (Figs 5A and EV5A), and the same region of the LBD—the C‐terminal end of h11 (Figs 5B and C, and EV5B), which in turn nudges h12 (Fig 5C and D). RESULTS 21 27 OBHS‐N chemical We observed that the OBHS‐N analogs displaced h11 along a vector away from Leu354 in a region of h3 that is unaffected by the ligands, and toward the dimer interface. RESULTS 46 49 h11 structure_element We observed that the OBHS‐N analogs displaced h11 along a vector away from Leu354 in a region of h3 that is unaffected by the ligands, and toward the dimer interface. RESULTS 75 81 Leu354 residue_name_number We observed that the OBHS‐N analogs displaced h11 along a vector away from Leu354 in a region of h3 that is unaffected by the ligands, and toward the dimer interface. RESULTS 97 99 h3 structure_element We observed that the OBHS‐N analogs displaced h11 along a vector away from Leu354 in a region of h3 that is unaffected by the ligands, and toward the dimer interface. RESULTS 150 165 dimer interface site We observed that the OBHS‐N analogs displaced h11 along a vector away from Leu354 in a region of h3 that is unaffected by the ligands, and toward the dimer interface. RESULTS 8 24 triaryl‐ethylene chemical For the triaryl‐ethylene analogs, the displacement of h11 was in a perpendicular direction, away from Ile424 in h8 and toward h12. RESULTS 54 57 h11 structure_element For the triaryl‐ethylene analogs, the displacement of h11 was in a perpendicular direction, away from Ile424 in h8 and toward h12. RESULTS 102 108 Ile424 residue_name_number For the triaryl‐ethylene analogs, the displacement of h11 was in a perpendicular direction, away from Ile424 in h8 and toward h12. RESULTS 112 114 h8 structure_element For the triaryl‐ethylene analogs, the displacement of h11 was in a perpendicular direction, away from Ile424 in h8 and toward h12. RESULTS 126 129 h12 structure_element For the triaryl‐ethylene analogs, the displacement of h11 was in a perpendicular direction, away from Ile424 in h8 and toward h12. RESULTS 29 51 inter‐atomic distances evidence Remarkably, these individual inter‐atomic distances showed a ligand class‐specific ability to significantly predict proliferative effects (Fig 5E and F), demonstrating the feasibility of developing a minimal set of activity predictors from crystal structures. RESULTS 240 258 crystal structures evidence Remarkably, these individual inter‐atomic distances showed a ligand class‐specific ability to significantly predict proliferative effects (Fig 5E and F), demonstrating the feasibility of developing a minimal set of activity predictors from crystal structures. RESULTS 0 24 Structure‐class analysis experimental_method Structure‐class analysis of triaryl‐ethylene analogs. FIG 28 44 triaryl‐ethylene chemical Structure‐class analysis of triaryl‐ethylene analogs. FIG 0 16 Triaryl‐ethylene chemical Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 25 33 bound to protein_state Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 38 48 superposed experimental_method Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 49 67 crystal structures evidence Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 75 78 ERα protein Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 79 82 LBD structure_element Triaryl‐ethylene analogs bound to the superposed crystal structures of the ERα LBD are shown. FIG 70 73 h11 structure_element Arrows indicate chemical variance in the orientation of the different h11‐directed ligand side groups (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF and 5DP0). FIG 0 16 Triaryl‐ethylene chemical Triaryl‐ethylene analogs induce variance of ERα conformations at the C‐terminal region of h11. FIG 44 47 ERα protein Triaryl‐ethylene analogs induce variance of ERα conformations at the C‐terminal region of h11. FIG 90 93 h11 structure_element Triaryl‐ethylene analogs induce variance of ERα conformations at the C‐terminal region of h11. FIG 20 37 crystal structure evidence Panel (B) shows the crystal structure of a triaryl‐ethylene analog‐bound ERα LBD (PDB 5DLR). FIG 43 59 triaryl‐ethylene chemical Panel (B) shows the crystal structure of a triaryl‐ethylene analog‐bound ERα LBD (PDB 5DLR). FIG 73 76 ERα protein Panel (B) shows the crystal structure of a triaryl‐ethylene analog‐bound ERα LBD (PDB 5DLR). FIG 77 80 LBD structure_element Panel (B) shows the crystal structure of a triaryl‐ethylene analog‐bound ERα LBD (PDB 5DLR). FIG 4 21 h11–h12 interface site The h11–h12 interface (circled) includes the C‐terminal part of h11. FIG 64 67 h11 structure_element The h11–h12 interface (circled) includes the C‐terminal part of h11. FIG 52 68 triaryl‐ethylene chemical This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 82 85 ERα protein This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 86 89 LBD structure_element This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 90 100 structures evidence This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 133 143 superposed experimental_method This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 170 173 h11 structure_element This region was expanded in panel (C), where the 10 triaryl‐ethylene analog‐bound ERα LBD structures (see Datasets EV1 and EV2) were superposed to show variations in the h11 C‐terminus (PDB 5DK9, 5DKB, 5DKE, 5DKG, 5DKS, 5DL4, 5DLR, 5DMC, 5DMF, and 5DP0). FIG 0 3 ERα protein ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 4 8 LBDs structure_element ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 9 24 in complex with protein_state ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 25 43 diethylstilbestrol chemical ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 45 48 DES chemical ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 55 71 triaryl‐ethylene chemical ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 84 94 superposed experimental_method ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 141 144 h11 structure_element ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 194 197 h12 structure_element ERα LBDs in complex with diethylstilbestrol (DES) or a triaryl‐ethylene analog were superposed to show that the ligand‐induced difference in h11 conformation is transmitted to the C‐terminus of h12 (PDB 4ZN7, 5DMC). FIG 0 22 Inter‐atomic distances evidence Inter‐atomic distances predict the proliferative effects of specific ligand series. FIG 0 6 Ile424 residue_name_number Ile424–His524 distance measured in the crystal structures correlates with the proliferative effect of triaryl‐ethylene analogs in MCF‐7 cells. FIG 7 13 His524 residue_name_number Ile424–His524 distance measured in the crystal structures correlates with the proliferative effect of triaryl‐ethylene analogs in MCF‐7 cells. FIG 14 22 distance evidence Ile424–His524 distance measured in the crystal structures correlates with the proliferative effect of triaryl‐ethylene analogs in MCF‐7 cells. FIG 39 57 crystal structures evidence Ile424–His524 distance measured in the crystal structures correlates with the proliferative effect of triaryl‐ethylene analogs in MCF‐7 cells. FIG 102 118 triaryl‐ethylene chemical Ile424–His524 distance measured in the crystal structures correlates with the proliferative effect of triaryl‐ethylene analogs in MCF‐7 cells. FIG 17 23 Leu354 residue_name_number In contrast, the Leu354–Leu525 distance correlates with the proliferative effects of OBHS‐N analogs in MCF‐7 cells. FIG 24 30 Leu525 residue_name_number In contrast, the Leu354–Leu525 distance correlates with the proliferative effects of OBHS‐N analogs in MCF‐7 cells. FIG 31 39 distance evidence In contrast, the Leu354–Leu525 distance correlates with the proliferative effects of OBHS‐N analogs in MCF‐7 cells. FIG 85 91 OBHS‐N chemical In contrast, the Leu354–Leu525 distance correlates with the proliferative effects of OBHS‐N analogs in MCF‐7 cells. FIG 0 24 Structure‐class analysis experimental_method Structure‐class analysis of WAY‐C analogs. FIG 28 33 WAY‐C chemical Structure‐class analysis of WAY‐C analogs. FIG 0 5 WAY‐C chemical WAY‐C side groups subtly nudge h12 Leu540. FIG 31 34 h12 structure_element WAY‐C side groups subtly nudge h12 Leu540. FIG 35 41 Leu540 residue_name_number WAY‐C side groups subtly nudge h12 Leu540. FIG 0 3 ERα protein ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 4 7 LBD structure_element ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 8 18 structures evidence ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 19 27 bound to protein_state ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 39 44 WAY‐C chemical ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 58 68 superposed experimental_method ERα LBD structures bound to 4 distinct WAY‐C analogs were superposed (PDB 4 IU7, 4IV4, 4IVW, 4IW6) (see Datasets EV1 and EV2). FIG 0 24 Structure‐class analysis experimental_method Structure‐class analysis of indirect modulators FIG 0 24 Structure‐class analysis experimental_method Structure‐class analysis of indirect modulators in cluster 1. FIG 0 18 Crystal structures evidence Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 26 29 ERα protein Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 30 33 LBD structure_element Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 34 42 bound to protein_state Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 43 47 OBHS chemical Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 52 58 OBHS‐N chemical Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 72 82 superposed experimental_method Crystal structures of the ERα LBD bound to OBHS and OBHS‐N analogs were superposed. FIG 70 73 h11 structure_element Arrows indicate chemical variance in the orientation of the different h11‐directed ligand side groups. FIG 88 91 h11 structure_element Panel (B) shows the ligand‐induced conformational variation at the C‐terminal region of h11 (OBHS: PDB 4ZN9, 4ZNH, 4ZNS, 4ZNT, 4ZNU, 4ZNV, and 4ZNW; OBHS‐N: PDB 4ZUB, 4ZUC, 4ZWH, 4ZWK, 5BNU, 5BP6, 5BPR, and 5BQ4). FIG 93 97 OBHS chemical Panel (B) shows the ligand‐induced conformational variation at the C‐terminal region of h11 (OBHS: PDB 4ZN9, 4ZNH, 4ZNS, 4ZNT, 4ZNU, 4ZNV, and 4ZNW; OBHS‐N: PDB 4ZUB, 4ZUC, 4ZWH, 4ZWK, 5BNU, 5BP6, 5BPR, and 5BQ4). FIG 149 155 OBHS‐N chemical Panel (B) shows the ligand‐induced conformational variation at the C‐terminal region of h11 (OBHS: PDB 4ZN9, 4ZNH, 4ZNS, 4ZNT, 4ZNU, 4ZNV, and 4ZNW; OBHS‐N: PDB 4ZUB, 4ZUC, 4ZWH, 4ZWK, 5BNU, 5BP6, 5BPR, and 5BQ4). FIG 0 24 Structure‐class analysis experimental_method Structure‐class analysis of indirect modulators in clusters 2 and 3. FIG 0 18 Crystal structures evidence Crystal structures of the ERα LBD bound to ligands with cell‐specific activities were superposed. FIG 26 29 ERα protein Crystal structures of the ERα LBD bound to ligands with cell‐specific activities were superposed. FIG 30 33 LBD structure_element Crystal structures of the ERα LBD bound to ligands with cell‐specific activities were superposed. FIG 34 42 bound to protein_state Crystal structures of the ERα LBD bound to ligands with cell‐specific activities were superposed. FIG 86 96 superposed experimental_method Crystal structures of the ERα LBD bound to ligands with cell‐specific activities were superposed. FIG 108 110 h3 structure_element The bound ligands are shown, and arrows indicate considerable variation in the orientation of the different h3‐, h8‐, h11‐, or h12‐directed ligand side groups. FIG 113 115 h8 structure_element The bound ligands are shown, and arrows indicate considerable variation in the orientation of the different h3‐, h8‐, h11‐, or h12‐directed ligand side groups. FIG 118 121 h11 structure_element The bound ligands are shown, and arrows indicate considerable variation in the orientation of the different h3‐, h8‐, h11‐, or h12‐directed ligand side groups. FIG 127 130 h12 structure_element The bound ligands are shown, and arrows indicate considerable variation in the orientation of the different h3‐, h8‐, h11‐, or h12‐directed ligand side groups. FIG 22 25 LBD structure_element As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 26 36 structures evidence As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 63 68 WAY‐C chemical As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 136 139 h12 structure_element As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 140 146 Leu540 residue_name_number As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 168 189 ligand‐binding pocket site As visualized in four LBD structures (Srinivasan et al, 2013), WAY‐C analogs were designed with small substitutions that slightly nudge h12 Leu540, without exiting the ligand‐binding pocket (Fig 5G and H). RESULTS 20 23 h12 structure_element Therefore, changing h12 dynamics maintains the canonical signaling pathway defined by E2 (Fig 1D) to support AF‐2‐driven signaling and recruit NCOA1/2/3 for GREB1‐stimulated proliferation. RESULTS 86 88 E2 chemical Therefore, changing h12 dynamics maintains the canonical signaling pathway defined by E2 (Fig 1D) to support AF‐2‐driven signaling and recruit NCOA1/2/3 for GREB1‐stimulated proliferation. RESULTS 109 113 AF‐2 structure_element Therefore, changing h12 dynamics maintains the canonical signaling pathway defined by E2 (Fig 1D) to support AF‐2‐driven signaling and recruit NCOA1/2/3 for GREB1‐stimulated proliferation. RESULTS 143 152 NCOA1/2/3 protein Therefore, changing h12 dynamics maintains the canonical signaling pathway defined by E2 (Fig 1D) to support AF‐2‐driven signaling and recruit NCOA1/2/3 for GREB1‐stimulated proliferation. RESULTS 157 162 GREB1 protein Therefore, changing h12 dynamics maintains the canonical signaling pathway defined by E2 (Fig 1D) to support AF‐2‐driven signaling and recruit NCOA1/2/3 for GREB1‐stimulated proliferation. RESULTS 59 71 AF‐2 surface site Ligands with cell‐specific activity alter the shape of the AF‐2 surface RESULTS 23 32 tamoxifen chemical Direct modulators like tamoxifen drive AF‐1‐dependent cell‐specific activity by completely occluding AF‐2, but it is not known how indirect modulators produce cell‐specific ERα activity. RESULTS 39 43 AF‐1 structure_element Direct modulators like tamoxifen drive AF‐1‐dependent cell‐specific activity by completely occluding AF‐2, but it is not known how indirect modulators produce cell‐specific ERα activity. RESULTS 101 105 AF‐2 structure_element Direct modulators like tamoxifen drive AF‐1‐dependent cell‐specific activity by completely occluding AF‐2, but it is not known how indirect modulators produce cell‐specific ERα activity. RESULTS 173 176 ERα protein Direct modulators like tamoxifen drive AF‐1‐dependent cell‐specific activity by completely occluding AF‐2, but it is not known how indirect modulators produce cell‐specific ERα activity. RESULTS 34 37 LBD structure_element Therefore, we examined another 50 LBD structures containing ligands in clusters 2 and 3. RESULTS 38 48 structures evidence Therefore, we examined another 50 LBD structures containing ligands in clusters 2 and 3. RESULTS 6 16 structures evidence These structures demonstrated that cell‐specific activity derived from altering the shape of the AF‐2 surface without an extended side chain. RESULTS 97 109 AF‐2 surface site These structures demonstrated that cell‐specific activity derived from altering the shape of the AF‐2 surface without an extended side chain. RESULTS 165 167 h3 structure_element Ligands in cluster 2 and cluster 3 showed conformational heterogeneity in parts of the scaffold that were directed toward multiple regions of the receptor including h3, h8, h11, h12, and/or the β‐sheets (Fig EV5C–G). RESULTS 169 171 h8 structure_element Ligands in cluster 2 and cluster 3 showed conformational heterogeneity in parts of the scaffold that were directed toward multiple regions of the receptor including h3, h8, h11, h12, and/or the β‐sheets (Fig EV5C–G). RESULTS 173 176 h11 structure_element Ligands in cluster 2 and cluster 3 showed conformational heterogeneity in parts of the scaffold that were directed toward multiple regions of the receptor including h3, h8, h11, h12, and/or the β‐sheets (Fig EV5C–G). RESULTS 178 181 h12 structure_element Ligands in cluster 2 and cluster 3 showed conformational heterogeneity in parts of the scaffold that were directed toward multiple regions of the receptor including h3, h8, h11, h12, and/or the β‐sheets (Fig EV5C–G). RESULTS 194 202 β‐sheets structure_element Ligands in cluster 2 and cluster 3 showed conformational heterogeneity in parts of the scaffold that were directed toward multiple regions of the receptor including h3, h8, h11, h12, and/or the β‐sheets (Fig EV5C–G). RESULTS 14 22 S‐OBHS‐2 chemical For instance, S‐OBHS‐2 and S‐OBHS‐3 analogs (Fig 2) had similar ERα activity profiles in the different cell types (Fig EV2A–C), but the 2‐ versus 3‐methyl substituted phenol rings altered the correlated signaling patterns in different cell types (Fig 3B lanes 7 and 12). RESULTS 27 35 S‐OBHS‐3 chemical For instance, S‐OBHS‐2 and S‐OBHS‐3 analogs (Fig 2) had similar ERα activity profiles in the different cell types (Fig EV2A–C), but the 2‐ versus 3‐methyl substituted phenol rings altered the correlated signaling patterns in different cell types (Fig 3B lanes 7 and 12). RESULTS 64 67 ERα protein For instance, S‐OBHS‐2 and S‐OBHS‐3 analogs (Fig 2) had similar ERα activity profiles in the different cell types (Fig EV2A–C), but the 2‐ versus 3‐methyl substituted phenol rings altered the correlated signaling patterns in different cell types (Fig 3B lanes 7 and 12). RESULTS 50 62 AF‐2 surface site This difference in ligand positioning altered the AF‐2 surface via a shift in the N‐terminus of h12, which directly contacts the coactivator. RESULTS 96 99 h12 structure_element This difference in ligand positioning altered the AF‐2 surface via a shift in the N‐terminus of h12, which directly contacts the coactivator. RESULTS 35 44 structure evidence This effect is evident in a single structure due to its 1 Å magnitude (Fig 6A and B). RESULTS 14 17 h12 structure_element The shifts in h12 residues Asp538 and Leu539 led to rotation of the coactivator peptide (Fig 6C). RESULTS 27 33 Asp538 residue_name_number The shifts in h12 residues Asp538 and Leu539 led to rotation of the coactivator peptide (Fig 6C). RESULTS 38 44 Leu539 residue_name_number The shifts in h12 residues Asp538 and Leu539 led to rotation of the coactivator peptide (Fig 6C). RESULTS 63 75 AF‐2 surface site Thus, cell‐specific activity can stem from perturbation of the AF‐2 surface without an extended side chain, which presumably alters the receptor–coregulator interaction profile. RESULTS 0 10 S‐OBHS‐2/3 chemical S‐OBHS‐2/3 analogs subtly distort the AF‐2 surface. FIG 38 50 AF‐2 surface site S‐OBHS‐2/3 analogs subtly distort the AF‐2 surface. FIG 20 37 crystal structure evidence Panel (A) shows the crystal structure of an S‐OBHS‐3‐bound ERα LBD (PDB 5DUH). FIG 44 58 S‐OBHS‐3‐bound protein_state Panel (A) shows the crystal structure of an S‐OBHS‐3‐bound ERα LBD (PDB 5DUH). FIG 59 62 ERα protein Panel (A) shows the crystal structure of an S‐OBHS‐3‐bound ERα LBD (PDB 5DUH). FIG 63 66 LBD structure_element Panel (A) shows the crystal structure of an S‐OBHS‐3‐bound ERα LBD (PDB 5DUH). FIG 4 20 h3–h12 interface site The h3–h12 interface (circled) at AF‐2 (pink) was expanded in panels (B, C). FIG 34 38 AF‐2 structure_element The h3–h12 interface (circled) at AF‐2 (pink) was expanded in panels (B, C). FIG 4 20 S‐OBHS‐2/3‐bound protein_state The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 21 24 ERα protein The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 25 29 LBDs structure_element The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 35 45 superposed experimental_method The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 64 66 h3 structure_element The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 85 90 NCOA2 protein The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 113 125 AF‐2 surface site The S‐OBHS‐2/3‐bound ERα LBDs were superposed to show shifts in h3 (panel B) and the NCOA2 peptide docked at the AF‐2 surface (panel C). FIG 0 18 Crystal structures evidence Crystal structures show that 2,5‐DTP analogs shift h3 and h11 further apart compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DRM, 5DRJ). FIG 29 36 2,5‐DTP chemical Crystal structures show that 2,5‐DTP analogs shift h3 and h11 further apart compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DRM, 5DRJ). FIG 51 53 h3 structure_element Crystal structures show that 2,5‐DTP analogs shift h3 and h11 further apart compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DRM, 5DRJ). FIG 58 61 h11 structure_element Crystal structures show that 2,5‐DTP analogs shift h3 and h11 further apart compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DRM, 5DRJ). FIG 101 109 estrogen chemical Crystal structures show that 2,5‐DTP analogs shift h3 and h11 further apart compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DRM, 5DRJ). FIG 66 79 2,5‐DTP‐bound protein_state The 2F o‐F c electron density map and F o‐F c difference map of a 2,5‐DTP‐bound structure (PDB 5DRJ) were contoured at 1.0 sigma and ± 3.0 sigma, respectively. FIG 80 89 structure evidence The 2F o‐F c electron density map and F o‐F c difference map of a 2,5‐DTP‐bound structure (PDB 5DRJ) were contoured at 1.0 sigma and ± 3.0 sigma, respectively. FIG 21 38 α‐carbon distance evidence Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 53 55 h3 structure_element Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 56 62 Thr347 residue_name_number Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 66 69 h11 structure_element Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 70 76 Leu525 residue_name_number Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 80 115 A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound protein_state Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 116 119 ERα protein Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 120 124 LBDs structure_element Average (mean + SEM) α‐carbon distance measured from h3 Thr347 to h11 Leu525 of A‐CD‐, 2,5‐DTP‐, and 3,4‐DTPD‐bound ERα LBDs. FIG 12 28 Student's t‐test experimental_method *Two‐tailed Student's t‐test, P = 0.002 (PDB A‐CD: 5DI7, 5DID, 5DIE, 5DIG, and 4PPS; 2,5‐DTP: 4IWC, 5DRM, and 5DRJ; 3,4‐DTPD: 5DTV and 5DU5). FIG 30 31 P evidence *Two‐tailed Student's t‐test, P = 0.002 (PDB A‐CD: 5DI7, 5DID, 5DIE, 5DIG, and 4PPS; 2,5‐DTP: 4IWC, 5DRM, and 5DRJ; 3,4‐DTPD: 5DTV and 5DU5). FIG 45 49 A‐CD chemical *Two‐tailed Student's t‐test, P = 0.002 (PDB A‐CD: 5DI7, 5DID, 5DIE, 5DIG, and 4PPS; 2,5‐DTP: 4IWC, 5DRM, and 5DRJ; 3,4‐DTPD: 5DTV and 5DU5). FIG 85 92 2,5‐DTP chemical *Two‐tailed Student's t‐test, P = 0.002 (PDB A‐CD: 5DI7, 5DID, 5DIE, 5DIG, and 4PPS; 2,5‐DTP: 4IWC, 5DRM, and 5DRJ; 3,4‐DTPD: 5DTV and 5DU5). FIG 116 124 3,4‐DTPD chemical *Two‐tailed Student's t‐test, P = 0.002 (PDB A‐CD: 5DI7, 5DID, 5DIE, 5DIG, and 4PPS; 2,5‐DTP: 4IWC, 5DRM, and 5DRJ; 3,4‐DTPD: 5DTV and 5DU5). FIG 0 18 Crystal structures evidence Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 31 39 3,4‐DTPD chemical Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 54 56 h3 structure_element Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 58 59 F structure_element Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 69 74 NCOA2 protein Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 102 106 A‐CD chemical Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 112 120 estrogen chemical Crystal structures show that a 3,4‐DTPD analog shifts h3 (F) and the NCOA2 (G) peptide compared to an A‐CD‐ring estrogen (PDB 4PPS, 5DTV). FIG 0 23 Hierarchical clustering experimental_method Hierarchical clustering of ligand‐specific binding of 154 interacting peptides to the ERα LBD was performed in triplicate by MARCoNI analysis. FIG 86 89 ERα protein Hierarchical clustering of ligand‐specific binding of 154 interacting peptides to the ERα LBD was performed in triplicate by MARCoNI analysis. FIG 90 93 LBD structure_element Hierarchical clustering of ligand‐specific binding of 154 interacting peptides to the ERα LBD was performed in triplicate by MARCoNI analysis. FIG 125 141 MARCoNI analysis experimental_method Hierarchical clustering of ligand‐specific binding of 154 interacting peptides to the ERα LBD was performed in triplicate by MARCoNI analysis. FIG 4 11 2,5‐DTP chemical The 2,5‐DTP analogs showed perturbation of h11, as well as h3, which forms part of the AF‐2 surface. RESULTS 43 46 h11 structure_element The 2,5‐DTP analogs showed perturbation of h11, as well as h3, which forms part of the AF‐2 surface. RESULTS 59 61 h3 structure_element The 2,5‐DTP analogs showed perturbation of h11, as well as h3, which forms part of the AF‐2 surface. RESULTS 87 99 AF‐2 surface site The 2,5‐DTP analogs showed perturbation of h11, as well as h3, which forms part of the AF‐2 surface. RESULTS 25 28 LBD structure_element These compounds bind the LBD in an unusual fashion because they have a phenol‐to‐phenol length of ~12 Å, which is longer than steroids and other prototypical ERα agonists that are ~10 Å in length. RESULTS 158 161 ERα protein These compounds bind the LBD in an unusual fashion because they have a phenol‐to‐phenol length of ~12 Å, which is longer than steroids and other prototypical ERα agonists that are ~10 Å in length. RESULTS 33 35 h3 structure_element One phenol pushed further toward h3 (Fig 6D), while the other phenol pushed toward the C‐terminus of h11 to a greater extent than A‐CD‐ring estrogens (Nwachukwu et al, 2014), which are close structural analogs of E2 that lack a B‐ring (Fig 2). RESULTS 101 104 h11 structure_element One phenol pushed further toward h3 (Fig 6D), while the other phenol pushed toward the C‐terminus of h11 to a greater extent than A‐CD‐ring estrogens (Nwachukwu et al, 2014), which are close structural analogs of E2 that lack a B‐ring (Fig 2). RESULTS 130 134 A‐CD chemical One phenol pushed further toward h3 (Fig 6D), while the other phenol pushed toward the C‐terminus of h11 to a greater extent than A‐CD‐ring estrogens (Nwachukwu et al, 2014), which are close structural analogs of E2 that lack a B‐ring (Fig 2). RESULTS 140 149 estrogens chemical One phenol pushed further toward h3 (Fig 6D), while the other phenol pushed toward the C‐terminus of h11 to a greater extent than A‐CD‐ring estrogens (Nwachukwu et al, 2014), which are close structural analogs of E2 that lack a B‐ring (Fig 2). RESULTS 213 215 E2 chemical One phenol pushed further toward h3 (Fig 6D), while the other phenol pushed toward the C‐terminus of h11 to a greater extent than A‐CD‐ring estrogens (Nwachukwu et al, 2014), which are close structural analogs of E2 that lack a B‐ring (Fig 2). RESULTS 45 53 distance evidence To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 75 77 h3 structure_element To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 78 84 Thr347 residue_name_number To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 89 92 h11 structure_element To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 93 99 Leu525 residue_name_number To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 114 124 structures evidence To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 136 143 2,5‐DTP chemical To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 163 167 A‐CD chemical To quantify this difference, we compared the distance between α‐carbons at h3 Thr347 and h11 Leu525 in the set of structures containing 2,5‐DTP analogs (n = 3) or A‐CD‐ring analogs (n = 5) (Fig 6E). RESULTS 67 83 Student's t‐test experimental_method We observed a difference of 0.4 Å that was significant (two‐tailed Student's t‐test, P = 0.002) due to the very tight clustering of the 2,5‐DTP‐induced LBD conformation. RESULTS 85 86 P evidence We observed a difference of 0.4 Å that was significant (two‐tailed Student's t‐test, P = 0.002) due to the very tight clustering of the 2,5‐DTP‐induced LBD conformation. RESULTS 136 143 2,5‐DTP chemical We observed a difference of 0.4 Å that was significant (two‐tailed Student's t‐test, P = 0.002) due to the very tight clustering of the 2,5‐DTP‐induced LBD conformation. RESULTS 152 155 LBD structure_element We observed a difference of 0.4 Å that was significant (two‐tailed Student's t‐test, P = 0.002) due to the very tight clustering of the 2,5‐DTP‐induced LBD conformation. RESULTS 14 16 h3 structure_element The shifts in h3 suggest these compounds are positioned to alter coregulator preferences. RESULTS 4 11 2,5‐DTP chemical The 2,5‐DTP and 3,4‐DTP scaffolds are isomeric, but with aryl groups at obtuse and acute angles, respectively (Fig 2). RESULTS 16 23 3,4‐DTP chemical The 2,5‐DTP and 3,4‐DTP scaffolds are isomeric, but with aryl groups at obtuse and acute angles, respectively (Fig 2). RESULTS 4 21 crystal structure evidence The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 25 28 ERα protein The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 29 44 in complex with protein_state The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 47 54 3,4‐DTP chemical The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 79 85 solved experimental_method The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 90 108 crystal structures evidence The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 112 115 ERα protein The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 116 124 bound to protein_state The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 125 133 3,4‐DTPD chemical The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 150 159 structure evidence The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 173 178 furan chemical The crystal structure of ERα in complex with a 3,4‐DTP is unknown; however, we solved two crystal structures of ERα bound to 3,4‐DTPD analogs and one structure containing a furan ligand—all of which have a 3,4‐diaryl configuration (Fig 2; Datasets EV1 and EV2). RESULTS 9 19 structures evidence In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 47 55 3,4‐DTPD chemical In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 71 73 h3 structure_element In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 74 80 Glu353 residue_name_number In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 130 132 h3 structure_element In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 143 156 hydrogen bond bond_interaction In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 162 168 Thr347 residue_name_number In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 217 220 ERα protein In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 221 242 ligand‐binding pocket site In these structures, the A‐ring mimetic of the 3,4‐DTPD scaffold bound h3 Glu353 as expected, but the other phenol wrapped around h3 to form a hydrogen bond with Thr347, indicating a change in binding epitopes in the ERα ligand‐binding pocket (Fig 6F). RESULTS 4 12 3,4‐DTPD chemical The 3,4‐DTPD analogs also induced a shift in h3 positioning, which translated again into a shift in the bound coactivator peptide (Fig 6F). RESULTS 45 47 h3 structure_element The 3,4‐DTPD analogs also induced a shift in h3 positioning, which translated again into a shift in the bound coactivator peptide (Fig 6F). RESULTS 48 56 S‐OBHS‐2 chemical Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 58 66 S‐OBHS‐3 chemical Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 68 75 2,5‐DTP chemical Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 81 89 3,4‐DTPD chemical Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 166 168 h3 structure_element Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 173 176 h12 structure_element Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 241 253 AF‐2 surface site Therefore, these indirect modulators, including S‐OBHS‐2, S‐OBHS‐3, 2,5‐DTP, and 3,4‐DTPD analogs—all of which show cell‐specific activity profiles—induced shifts in h3 and h12 that were transmitted to the coactivator peptide via an altered AF‐2 surface. RESULTS 20 32 AF‐2 surface site To test whether the AF‐2 surface shows changes in shape in solution, we used the microarray assay for real‐time coregulator–nuclear receptor interaction (MARCoNI) analysis (Aarts et al, 2013). RESULTS 81 152 microarray assay for real‐time coregulator–nuclear receptor interaction experimental_method To test whether the AF‐2 surface shows changes in shape in solution, we used the microarray assay for real‐time coregulator–nuclear receptor interaction (MARCoNI) analysis (Aarts et al, 2013). RESULTS 154 161 MARCoNI experimental_method To test whether the AF‐2 surface shows changes in shape in solution, we used the microarray assay for real‐time coregulator–nuclear receptor interaction (MARCoNI) analysis (Aarts et al, 2013). RESULTS 47 50 ERα protein Here, the ligand‐dependent interactions of the ERα LBD with over 150 distinct LxxLL motif peptides were assayed to define structural fingerprints for the AF‐2 surface, in a manner similar to the use of phage display peptides as structural probes (Connor et al, 2001). RESULTS 51 54 LBD structure_element Here, the ligand‐dependent interactions of the ERα LBD with over 150 distinct LxxLL motif peptides were assayed to define structural fingerprints for the AF‐2 surface, in a manner similar to the use of phage display peptides as structural probes (Connor et al, 2001). RESULTS 78 89 LxxLL motif structure_element Here, the ligand‐dependent interactions of the ERα LBD with over 150 distinct LxxLL motif peptides were assayed to define structural fingerprints for the AF‐2 surface, in a manner similar to the use of phage display peptides as structural probes (Connor et al, 2001). RESULTS 154 166 AF‐2 surface site Here, the ligand‐dependent interactions of the ERα LBD with over 150 distinct LxxLL motif peptides were assayed to define structural fingerprints for the AF‐2 surface, in a manner similar to the use of phage display peptides as structural probes (Connor et al, 2001). RESULTS 202 224 phage display peptides experimental_method Here, the ligand‐dependent interactions of the ERα LBD with over 150 distinct LxxLL motif peptides were assayed to define structural fingerprints for the AF‐2 surface, in a manner similar to the use of phage display peptides as structural probes (Connor et al, 2001). RESULTS 79 86 2,5‐DTP chemical Despite the similar average activities of these ligand classes (Fig 3A and B), 2,5‐DTP and 3,4‐DTP analogs displayed remarkably different peptide recruitment patterns (Fig 6H), consistent with the structural analyses. RESULTS 91 98 3,4‐DTP chemical Despite the similar average activities of these ligand classes (Fig 3A and B), 2,5‐DTP and 3,4‐DTP analogs displayed remarkably different peptide recruitment patterns (Fig 6H), consistent with the structural analyses. RESULTS 197 216 structural analyses experimental_method Despite the similar average activities of these ligand classes (Fig 3A and B), 2,5‐DTP and 3,4‐DTP analogs displayed remarkably different peptide recruitment patterns (Fig 6H), consistent with the structural analyses. RESULTS 0 23 Hierarchical clustering experimental_method Hierarchical clustering revealed that many of the 2,5‐DTP analogs recapitulated most of the peptide recruitment and dismissal patterns observed with E2 (Fig 6H). RESULTS 50 57 2,5‐DTP chemical Hierarchical clustering revealed that many of the 2,5‐DTP analogs recapitulated most of the peptide recruitment and dismissal patterns observed with E2 (Fig 6H). RESULTS 149 151 E2 chemical Hierarchical clustering revealed that many of the 2,5‐DTP analogs recapitulated most of the peptide recruitment and dismissal patterns observed with E2 (Fig 6H). RESULTS 71 73 E2 chemical However, there was a unique cluster of peptides that were recruited by E2 but not the 2,5‐DTP analogs. RESULTS 86 93 2,5‐DTP chemical However, there was a unique cluster of peptides that were recruited by E2 but not the 2,5‐DTP analogs. RESULTS 13 20 3,4‐DTP chemical In contrast, 3,4‐DTP analogs dismissed most of the peptides from the AF‐2 surface (Fig 6H). RESULTS 69 81 AF‐2 surface site In contrast, 3,4‐DTP analogs dismissed most of the peptides from the AF‐2 surface (Fig 6H). RESULTS 54 63 thiophene chemical Thus, the isomeric attachment of diaryl groups to the thiophene core changed the AF‐2 surface from inside the ligand‐binding pocket, as predicted by the crystal structures. RESULTS 81 93 AF‐2 surface site Thus, the isomeric attachment of diaryl groups to the thiophene core changed the AF‐2 surface from inside the ligand‐binding pocket, as predicted by the crystal structures. RESULTS 110 131 ligand‐binding pocket site Thus, the isomeric attachment of diaryl groups to the thiophene core changed the AF‐2 surface from inside the ligand‐binding pocket, as predicted by the crystal structures. RESULTS 153 171 crystal structures evidence Thus, the isomeric attachment of diaryl groups to the thiophene core changed the AF‐2 surface from inside the ligand‐binding pocket, as predicted by the crystal structures. RESULTS 198 210 AF‐2 surface site Together, these findings suggest that without an extended side chain, cell‐specific activity stems from different coregulator recruitment profiles, due to unique ligand‐induced conformations of the AF‐2 surface, in addition to differential usage of AF‐1. RESULTS 249 253 AF‐1 structure_element Together, these findings suggest that without an extended side chain, cell‐specific activity stems from different coregulator recruitment profiles, due to unique ligand‐induced conformations of the AF‐2 surface, in addition to differential usage of AF‐1. RESULTS 62 79 h11–h12 interface site Indirect modulators in cluster 1 avoid this by perturbing the h11–h12 interface, and modulating the dynamics of h12 without changing the shape of AF‐2 when stabilized. RESULTS 112 115 h12 structure_element Indirect modulators in cluster 1 avoid this by perturbing the h11–h12 interface, and modulating the dynamics of h12 without changing the shape of AF‐2 when stabilized. RESULTS 146 150 AF‐2 structure_element Indirect modulators in cluster 1 avoid this by perturbing the h11–h12 interface, and modulating the dynamics of h12 without changing the shape of AF‐2 when stabilized. RESULTS 106 109 ERα protein Our goal was to identify a minimal set of predictors that would link specific structural perturbations to ERα signaling pathways that control cell‐specific signaling and proliferation. DISCUSS 148 151 h12 structure_element We found a very strong set of predictors, where ligands in cluster 1, defined by similar signaling across cell types, showed indirect modulation of h12 dynamics via the h11–12 interface or slight contact with h12. DISCUSS 169 185 h11–12 interface site We found a very strong set of predictors, where ligands in cluster 1, defined by similar signaling across cell types, showed indirect modulation of h12 dynamics via the h11–12 interface or slight contact with h12. DISCUSS 209 212 h12 structure_element We found a very strong set of predictors, where ligands in cluster 1, defined by similar signaling across cell types, showed indirect modulation of h12 dynamics via the h11–12 interface or slight contact with h12. DISCUSS 73 77 AF‐2 structure_element This perturbation determined proliferation that correlated strongly with AF‐2 activity, recruitment of NCOA1/2/3 family members, and induction of the GREB1 gene, consistent with the canonical ERα signaling pathway (Fig 1D). DISCUSS 103 112 NCOA1/2/3 protein This perturbation determined proliferation that correlated strongly with AF‐2 activity, recruitment of NCOA1/2/3 family members, and induction of the GREB1 gene, consistent with the canonical ERα signaling pathway (Fig 1D). DISCUSS 150 155 GREB1 protein This perturbation determined proliferation that correlated strongly with AF‐2 activity, recruitment of NCOA1/2/3 family members, and induction of the GREB1 gene, consistent with the canonical ERα signaling pathway (Fig 1D). DISCUSS 192 195 ERα protein This perturbation determined proliferation that correlated strongly with AF‐2 activity, recruitment of NCOA1/2/3 family members, and induction of the GREB1 gene, consistent with the canonical ERα signaling pathway (Fig 1D). DISCUSS 26 34 deletion experimental_method For ligands in cluster 1, deletion of AF‐1 reduced activity to varying degrees, but did not change the underlying signaling patterns established through AF‐2. DISCUSS 38 42 AF‐1 structure_element For ligands in cluster 1, deletion of AF‐1 reduced activity to varying degrees, but did not change the underlying signaling patterns established through AF‐2. DISCUSS 153 157 AF‐2 structure_element For ligands in cluster 1, deletion of AF‐1 reduced activity to varying degrees, but did not change the underlying signaling patterns established through AF‐2. DISCUSS 68 71 h12 structure_element In contrast, an extended side chain designed to directly reposition h12 and completely disrupt the AF‐2 surface results in cell‐specific signaling. DISCUSS 99 111 AF‐2 surface site In contrast, an extended side chain designed to directly reposition h12 and completely disrupt the AF‐2 surface results in cell‐specific signaling. DISCUSS 137 140 LBD structure_element Compared to cluster 1, the structural rules are less clear in clusters 2 and 3, but a number of indirect modulator classes perturbed the LBD conformation at the intersection of h3, the h12 N‐terminus, and the AF‐2 surface. DISCUSS 177 179 h3 structure_element Compared to cluster 1, the structural rules are less clear in clusters 2 and 3, but a number of indirect modulator classes perturbed the LBD conformation at the intersection of h3, the h12 N‐terminus, and the AF‐2 surface. DISCUSS 185 188 h12 structure_element Compared to cluster 1, the structural rules are less clear in clusters 2 and 3, but a number of indirect modulator classes perturbed the LBD conformation at the intersection of h3, the h12 N‐terminus, and the AF‐2 surface. DISCUSS 209 221 AF‐2 surface site Compared to cluster 1, the structural rules are less clear in clusters 2 and 3, but a number of indirect modulator classes perturbed the LBD conformation at the intersection of h3, the h12 N‐terminus, and the AF‐2 surface. DISCUSS 46 50 AF‐2 structure_element Ligands in these classes altered the shape of AF‐2 to affect coregulator preferences. DISCUSS 68 71 ERα protein For direct and indirect modulators in cluster 2 or 3, the canonical ERα signaling pathway involving recruitment of NCOA1/2/3 and induction of GREB1 did not generally predict their proliferative effects, indicating an alternate causal model (Fig 1E). DISCUSS 115 124 NCOA1/2/3 protein For direct and indirect modulators in cluster 2 or 3, the canonical ERα signaling pathway involving recruitment of NCOA1/2/3 and induction of GREB1 did not generally predict their proliferative effects, indicating an alternate causal model (Fig 1E). DISCUSS 142 147 GREB1 protein For direct and indirect modulators in cluster 2 or 3, the canonical ERα signaling pathway involving recruitment of NCOA1/2/3 and induction of GREB1 did not generally predict their proliferative effects, indicating an alternate causal model (Fig 1E). DISCUSS 71 96 ligand–receptor interface site These principles outlined above provide a structural basis for how the ligand–receptor interface leads to different signaling specificities through AF‐1 and AF‐2. DISCUSS 148 152 AF‐1 structure_element These principles outlined above provide a structural basis for how the ligand–receptor interface leads to different signaling specificities through AF‐1 and AF‐2. DISCUSS 157 161 AF‐2 structure_element These principles outlined above provide a structural basis for how the ligand–receptor interface leads to different signaling specificities through AF‐1 and AF‐2. DISCUSS 36 39 h12 structure_element It is noteworthy that regulation of h12 dynamics indirectly through h11 can virtually abolish AF‐2 activity, and yet still drive robust transcriptional activity through AF‐1, as demonstrated with the OBHS series. DISCUSS 68 71 h11 structure_element It is noteworthy that regulation of h12 dynamics indirectly through h11 can virtually abolish AF‐2 activity, and yet still drive robust transcriptional activity through AF‐1, as demonstrated with the OBHS series. DISCUSS 94 98 AF‐2 structure_element It is noteworthy that regulation of h12 dynamics indirectly through h11 can virtually abolish AF‐2 activity, and yet still drive robust transcriptional activity through AF‐1, as demonstrated with the OBHS series. DISCUSS 169 173 AF‐1 structure_element It is noteworthy that regulation of h12 dynamics indirectly through h11 can virtually abolish AF‐2 activity, and yet still drive robust transcriptional activity through AF‐1, as demonstrated with the OBHS series. DISCUSS 200 204 OBHS chemical It is noteworthy that regulation of h12 dynamics indirectly through h11 can virtually abolish AF‐2 activity, and yet still drive robust transcriptional activity through AF‐1, as demonstrated with the OBHS series. DISCUSS 47 56 NCOA1/2/3 protein This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 74 87 binding sites site This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 109 113 AF‐1 structure_element This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 118 122 AF‐2 structure_element This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 199 212 ERα–NCOA1/2/3 complex_assembly This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 233 237 AF‐2 structure_element This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 297 301 AF‐1 structure_element This finding can be explained by the fact that NCOA1/2/3 contain distinct binding sites for interaction with AF‐1 and AF‐2 (McInerney et al, 1996; Webb et al, 1998), which allows ligands to nucleate ERα–NCOA1/2/3 interaction through AF‐2, and reinforce this interaction with additional binding to AF‐1. DISCUSS 20 24 AF‐2 structure_element Completely blocking AF‐2 with an extended side chain or altering the shape of AF‐2 changes the preference away from NCOA1/2/3 for determining GREB1 levels and proliferation of breast cancer cells. DISCUSS 78 82 AF‐2 structure_element Completely blocking AF‐2 with an extended side chain or altering the shape of AF‐2 changes the preference away from NCOA1/2/3 for determining GREB1 levels and proliferation of breast cancer cells. DISCUSS 116 125 NCOA1/2/3 protein Completely blocking AF‐2 with an extended side chain or altering the shape of AF‐2 changes the preference away from NCOA1/2/3 for determining GREB1 levels and proliferation of breast cancer cells. DISCUSS 142 147 GREB1 protein Completely blocking AF‐2 with an extended side chain or altering the shape of AF‐2 changes the preference away from NCOA1/2/3 for determining GREB1 levels and proliferation of breast cancer cells. DISCUSS 0 4 AF‐2 structure_element AF‐2 blockade also allows AF‐1 to function independently, which is important since AF‐1 drives tissue‐selective effects in vivo. DISCUSS 26 30 AF‐1 structure_element AF‐2 blockade also allows AF‐1 to function independently, which is important since AF‐1 drives tissue‐selective effects in vivo. DISCUSS 83 87 AF‐1 structure_element AF‐2 blockade also allows AF‐1 to function independently, which is important since AF‐1 drives tissue‐selective effects in vivo. DISCUSS 27 31 AF‐1 structure_element This was demonstrated with AF‐1 knockout mice that show E2‐dependent vascular protection, but not uterine proliferation, thus highlighting the role of AF‐1 in tissue‐selective or cell‐specific signaling (Billon‐Gales et al, 2009; Abot et al, 2013). DISCUSS 56 58 E2 chemical This was demonstrated with AF‐1 knockout mice that show E2‐dependent vascular protection, but not uterine proliferation, thus highlighting the role of AF‐1 in tissue‐selective or cell‐specific signaling (Billon‐Gales et al, 2009; Abot et al, 2013). DISCUSS 151 155 AF‐1 structure_element This was demonstrated with AF‐1 knockout mice that show E2‐dependent vascular protection, but not uterine proliferation, thus highlighting the role of AF‐1 in tissue‐selective or cell‐specific signaling (Billon‐Gales et al, 2009; Abot et al, 2013). DISCUSS 23 26 LBD structure_element Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 27 37 structures evidence Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 103 106 ERβ protein Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 133 137 AF‐1 structure_element Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 153 158 NCOA3 protein Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 176 181 GREB1 protein Here, we examined many LBD structures and tested several variables that were not predictive, including ERβ activity, the strength of AF‐1 signaling, and NCOA3 occupancy at the GREB1 gene. DISCUSS 25 35 structures evidence Similarly, we visualized structures to identify patterns. DISCUSS 13 26 phage display experimental_method For example, phage display was used to identify the androgen receptor interactome, which was cloned into an M2H library and used to identify clusters of ligand‐selective interactions (Norris et al, 2009). DISCUSS 108 111 M2H experimental_method For example, phage display was used to identify the androgen receptor interactome, which was cloned into an M2H library and used to identify clusters of ligand‐selective interactions (Norris et al, 2009). DISCUSS 19 34 siRNA screening experimental_method Also, we have used siRNA screening to identify a number of coregulators required for ERα‐mediated repression of the IL‐6 gene (Nwachukwu et al, 2014). DISCUSS 85 88 ERα protein Also, we have used siRNA screening to identify a number of coregulators required for ERα‐mediated repression of the IL‐6 gene (Nwachukwu et al, 2014). DISCUSS 17 47 inter‐atomic distance matrices evidence If we calculated inter‐atomic distance matrices containing 4,000 atoms per structure × 76 ligand–receptor complexes, we would have 3 × 105 predictions. DISCUSS 19 33 atomic vectors evidence We have identified atomic vectors for the OBHS‐N and triaryl‐ethylene classes that predict ligand response (Fig 5E and F). DISCUSS 42 48 OBHS‐N chemical We have identified atomic vectors for the OBHS‐N and triaryl‐ethylene classes that predict ligand response (Fig 5E and F). DISCUSS 53 69 triaryl‐ethylene chemical We have identified atomic vectors for the OBHS‐N and triaryl‐ethylene classes that predict ligand response (Fig 5E and F). DISCUSS 52 58 OBHS‐N chemical Indeed, the most anti‐proliferative compound in the OBHS‐N series had a fulvestrant‐like profile across a battery of assays (S. Srinivasan et al, in preparation). DISCUSS 27 32 WAY‐C chemical Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 58 62 AF‐1 structure_element Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 127 130 h12 structure_element Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 143 161 crystal structures evidence Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 231 234 h11 structure_element Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 247 251 AF‐1 structure_element Secondly, our finding that WAY‐C compounds do not rely of AF‐1 for signaling efficacy may derive from the slight contacts with h12 observed in crystal structures (Figs 3B and 5H), unlike other compounds in cluster 1 that dislocate h11 and rely on AF‐1 for signaling efficacy (Figs 3B and 5C, and EV5B). DISCUSS 47 59 AF‐2 surface site Some of these ligands altered the shape of the AF‐2 surface by perturbing the h3–h12 interface, thus providing a route to new SERM‐like activity profiles by combining indirect and direct modulation of receptor structure. DISCUSS 78 94 h3–h12 interface site Some of these ligands altered the shape of the AF‐2 surface by perturbing the h3–h12 interface, thus providing a route to new SERM‐like activity profiles by combining indirect and direct modulation of receptor structure. DISCUSS 156 159 ERα protein Incorporation of statistical approaches to understand relationships between structure and signaling variables moves us toward predictive models for complex ERα‐mediated responses such as in vivo uterine proliferation or tumor growth, and more generally toward structure‐based design for other allosteric drug targets including GPCRs and other nuclear receptors. DISCUSS 327 332 GPCRs protein_type Incorporation of statistical approaches to understand relationships between structure and signaling variables moves us toward predictive models for complex ERα‐mediated responses such as in vivo uterine proliferation or tumor growth, and more generally toward structure‐based design for other allosteric drug targets including GPCRs and other nuclear receptors. DISCUSS 343 360 nuclear receptors protein_type Incorporation of statistical approaches to understand relationships between structure and signaling variables moves us toward predictive models for complex ERα‐mediated responses such as in vivo uterine proliferation or tumor growth, and more generally toward structure‐based design for other allosteric drug targets including GPCRs and other nuclear receptors. DISCUSS