EMBO/SourceData huggingface dataset:
Figure 2(B-D) - Immunostaining of 3rd instar larval eye imaginal discs with eyeless-Flippase-induced clones of cells homozygous for EMC3Δ4, labelled by the absence of ubiGFP (green) shows reduced expression of (B) UAS-HA-Xport-A (anti-HA, in blue) but normal expression of (C) UAS-HA-Xport-A4L (anti-HA, in blue) or (D) UAS-Xport-A4L-HA (anti-HA, in blue) in EMC3 mutant homozygous cells. ELAV (red in B and C) marks photoreceptor cells and Na+K+ATPase (red in D) acts as a positive control for the presence of EMC3Δ4 homozygous mutant clones. The UAS constructs were expressed under the control of GMR-GAL4. Scale bars represent 10 μm.(E-F) Immunostaining of mosaic adult retina with eyeless-Flippase-induced clones of cells homozygous for EMC3e02662, labelled by the absence of RFP (red), show loss of (E) UAS-HA-Xport-A (anti-HA, in blue) in EMC3 mutant homozygous cells. (F) Expression of UAS-HA-Xport-A4L (anti-HA, in blue) is normal in EMC3e02662 homozygous mutant clones. The rhabdomeres are stained for actin (Phalloidin, in green). Scale bars represent 10 μm.
Figure 3(B-D) Histograms of flow cytometry data monitoring the fluorescence protein ratio in the indicated U2OS cell lines for each construct. "EMC5KO+EV" indicates a knockout of EMC5 stably harbouring empty vector, while ''EMC5KO+EMC5" indicates EMC5KO cells rescued by inducible re-expression of a stably integrated EMC5. (E-G) Histograms of flow cytometry data monitoring the fluorescence protein ratio in the indicated U2OS cell lines for each construct. "EMC6KO+EV" indicates a knockout of EMC6 stably harbouring empty vector, while ''EMC6KO+EMC6" indicates EMC6KO cells rescued by re-expression of a stably integrated EMC6.
Figure 4(C-G) (C-D, F) Western-Blot of WT and EMC6KO (6KO) U2OS cell lines transiently transfected with the opsin-tagged constructs probed for HA. When indicated, denatured samples were treated with PNGase to confirm glycosylation. Glycosylated proteins shift upwards in the gel and are indicated by arrows (). (E, G) Western-Blot of WT and EMC6KO (6KO) U2OS cell lines transiently transfected with the opsin-tagged constructs probed for Actin and EMC6.
Figure 5(A-B) Immunostaining of 3rd instar larval eye imaginal discs with eyeless-Flippase-induced clones of cells homozygous for EMC3Δ4, labelled by the absence of ubiGFP (green) show loss of (A) UAS-Xport-A-HA (anti-HA, in blue) and UAS-Rh1 (4C5, in red). (B) Expression of UAS-Xport-A4L (anti-HA, in blue) and UAS-Rh1 (4C5, in red) is observed in EMC3Δ4 homozygous cells. The UAS constructs were expressed under the control of GMR-GAL4. Scale bars represent 10 μm.(C-D) Immunostaining of mosaic adult retinas with eyeless-Flippase-induced clones of cells homozygous for EMC3e02662, labelled by the absence of RFP (red), show loss of (C) TRP (Mab83F6, in blue) when UAS-HA-Xport-A is expressed. (D) Expression of TRP (Mab83F6, in blue) is observed in EMC3e02662 homozygous cells, when HA-Xport-A4L is expressed. The rhabdomeres are stained for actin (Phalloidin, in green). The UAS constructs were expressed under the control of Rh1-GAL4. Scale bars represent 10 μm.
Figure 6(E-G) Western blot of fly heads labelled for V5, TRP, Rh1, Xport-A (Xp-A) and tubulin. (E) Immunoblot of fly heads expressing Rh1Gal4 (driver) (left) or Rh1 TMD1-V5 (right) in Xport-A heterozygous (Xport-A1/TM6B) or homozygous mutant flies (Xport-A1/Xport-A1). Extracts were untreated (-) or treated (+) with PNGase F enzyme (lanes 2, 4, 6 and 8). For Rh1Gal4, 4 fly heads were loaded per well, while for Rh1 TMD1-V5, 8 fly heads were loaded per well. (F) Immunoblot of fly heads expressing Rh1 TMD1-3-V5 in Xport-A heterozygous (Xport-A1/TM6B) or homozygous mutant flies (Xport-A1/Xport-A1). Extracts were untreated (-) or treated (+) with PNGase F enzyme (lanes 2 and 4). Eight fly heads were loaded per lane. (G) Immunoblot of fly heads expressing Rh1 TMD1-5-V5 in Xport-A heterozygote (Xport-A1/TM6B) or homozygous mutant flies (Xport-A1/Xport-A1). Extracts were untreated (-) or treated (+) with either Endo-H (lanes 2 and 5) or PNGase F enzyme (lanes 3 and 6). Each lane contains approximately 2,5 fly heads.
figf1. (b) Conjugation of LC3 and two other mammalian homologues (GL1 and GL2) with phosphatidylethanolamine (PE) was performed as described in ref. . Complete reactions contain 1.5 μM Atg7, 2.5 μM Atg3, 8-12 μM LC3/GL1/GL2, 2 mM lipid (30 nm liposomes composed of 10 mol% bl-PI, 55 mol% DOPE, 0.15 mol% Rh-DOPE and 34.85 mol% POPC; see Methods for full definitions), 1 mM dithiothreitol and 1 mM ATP and were run at 30 °C for 90 min. Each reaction was run on a 12% SDS-PAGE gel and visualized by Coomassie blue stain. The mobility of the lipidated protein is faster than the corresponding non-lipidated forms. Intermediates in the reaction are also detectable, including the Atg7-GRL1 conjugate, the Atg3-GRL1 conjugate and a modified form of GRL1, GRL2 and LC3 that is labelled simply as GRL1/GRL2/LC3-intermediate and is probably the adenylated form of each LC3-related protein.(c) The lipidation reactions are highly dependent on the molar percentage of DOPE in the liposomes. Reactions are as in b, but run on 400 nm liposomes. Liposomes are composed of the indicated amount of DOPE, 10 mol% bl-PI, 0.15 mol% Rh-DOPE and POPC.(d) Completed reactions in c were subjected to density gradient flotation to isolate only the lipidated material. Floated samples were run on SDS-PAGE and imaged by Coomassie. For c and d, the samples were prepared at the same time from the same materials and run simultaneously on multiple gels, as indicated by the vertical lines. Uncropped versions of all gels are included in Supplementary Fig. 7.
figf2(b) Filling the defects with inverted cone-shaped lipids inhibits lipidation. In vitro coupling reactions of GL1 were run on sonicated liposomes containing 30 mol% DOPE (2 mM total lipid) as in Fig. 1. To determine whether inverted cones influenced the reaction, increasing amounts of stearoyl-CoA were added immediately before initiating the reaction with ATP. Quantification is of n = 3 samples; error bars represent standard deviation. P values represent a comparison with samples without stearoyl-CoA. **P 0.1; *P 0.05.(c) Altering the shape of PE to reduce local membrane defects inhibits the lipidation reaction. In vitro coupling reactions of GL1 were run on liposomes of three different sizes (400 nm and 50 nm extruded liposomes and sonicated liposomes) and of three different lipid compositions. Lipid compositions include 30 mol% DPPE, DSPE or DOPE (see Methods for full definitions), 10% bl-PI, and POPC. Total lipid = 2 mM. Quantification is of n = 3 samples; error bars represent standard deviation. The extent of lipidation in b and c is plotted as a percentage of total GL1 as determined by densitometry. P values represent comparison with most active liposomes (sonicated DOPE). **P 0.1; *P 0.05.
figf3(b) To determine the impact of curvature on lipidation, we compared liposomes with unphysiologically high surface densities of PE (55 mol%) as have been used in other Atg8 or LC3 lipidation publications (for example, refs , , ), with liposomes having the highest densities of liposomes observed in mammalian organelle membranes (30 mol%). At physiologically relevant concentrations of liposomes (30 mol%), lipidation becomes membrane curvature dependent. In vitro coupling reactions were performed as in Fig. 1, except that liposomes were made by extrusion through membranes with different pore diameters (as indicated). Actual diameters of these liposomes were determined by dynamic light scattering (Supplementary Table 1). Top: the lipidation of GL2, GL2 and PE proceeds efficiently and with relatively little curvature dependence on liposomes composed of 55% PE. However, when the liposomes is reduced to 30%, flat liposomes are no longer suitable for lipidation, while highly curved liposomes (100 nm diameter or less) continue to couple effectively. Bottom: to confirm that this curvature dependence reveals the lipidated product and not the intermediate, the 30% reactions were each run on Nycodenz flotation gradients. Only the lipidated product is recovered at the top of the gradient.(c) The lipidation reaction is largely insensitive to PE concentrations when run on highly curved liposomes. Coupling of GL1 and LC3 to PE was assessed on liposomes of two sizes (400 nm, black squares; sonicated, red circles) and varying molar percentage of DOPE. The extent of lipidation is determined as in Fig. 2. (n = 2 for 30 and 55% PE, n = 4 for all the other points, and error bars represent standard deviation.) P values were determined by comparing sonicated with 400 nm samples at each PE concentration. **P 0.1; *P 0.01. Uncropped versions of all gels are included in Supplementary Fig. 7.
figf4(a) The accumulation of the Atg3-GL1 conjugate depends on the extent of membrane curvature. In vitro GL1 coupling reactions were run as in Fig. 1. The reactions were visualized by immunoblot against Atg3 (top) and by Coomassie staining of GRL1 (bottom). The accumulation of Atg3-GL1 is inversely related to the formation of the lipidated GRL1, suggesting that the membrane-curvature-dependent step may involve Atg3 recognition of the membrane surface.(b) Atg3 binding to liposomes. Atg3 (10 μM) was incubated at 30 °C for 90 min with liposomes containing 0, 30 or 55 mol% DOPE (5 mM lipids) and of varying sizes (extrusion membrane dimensions are shown on the figure; actual final sizes were determined by dynamic light scattering (Supplementary Table 1)). The liposome-associated Atg3 was recovered by Nycodenz density gradient centrifugation and analysed by SDS-PAGE.(c) Quantification of liposome-associated Atg3. Densitometric plot of the amount of Atg3 recovered in the top fraction in flotation assays as in b. Error bars indicate s.e.m. from three independent experiments. P values calculated as compared with putative negative control (0% PE, 400 nm). *P 0.05. Uncropped versions of all gels are included in Supplementary Fig. 7.
figf5(b) Analysis of reaction efficiency for point mutants of the amphipathic helix. GL1 lipidation reactions were run on 400 nm and sonicated liposomes (30 mol% DOPE) with the indicated Atg3 mutants. The extent of GL1-PE formation (top gel) was determined from densitometry and is plotted as percentage of total GL1 (bar graph). The ability to form the Atg3-GL1 conjugate was also assessed for each mutant (bottom immunoblot). Note that this conjugate forms in every case, indicating that no mutant inhibited a step upstream in the reaction. Further, this conjugate specifically accumulates in reactions where lipidation is impaired. In both panels, the samples were prepared at the same time from the same materials and run simultaneously on multiple gels, as indicated by the lines.(c) Curvature dependence of K11L mutant binding to liposomes compared with wild-type Atg3. The binding reaction was performed as in Fig. 4b on 30 DOPE% liposomes. F, float-up; T, total input.(d) Lys 11 represents a tunable node through which curvature dependence of the lipidation reaction can be controlled. Lipidation assays were run as in b. Total GL1 lipidation was assessed from reactions with wild-type Atg3 or mutant forms of Atg3 in which position Lys 11 was changed as indicated. Lipidation efficiency on low PE/low curvature liposomes (30% PE, 400 nm) increases with increasing hydrophobicity of the new amino acid, while liposomes with high PE (55%) or high curvature (sonicated) are good substrates for all active forms of Atg3. Left: Coomassie gels of individual lipidation reactions. Right: densitometry of Coomassie-stained gels revealed the ratio of GL1-PE to the sum of all three GL1 species as in Fig. 2. Light grey bars are sonicated liposomes; dark grey bars are 400 nm extruded liposomes. For b,c, P values were calculated between sonicated and 400 nm samples of the same mutant. For d, P values represent comparison with WT protein on the same liposome size and composition. For all panels, n = 3 independent experiments, error bars represent standard deviation and **P 0.05; *P 0.01. Uncropped gels in Supplementary Fig. 7.
figf6Atg3-knockout MEFs (Atg3−/−) are incapable of forming LC3-II and do not accumulate LC3 puncta. Instead, they accumulate autophagic intermediates that are positive for Atg16. To determine whether the amphipathic helix is critical for in vivo function, Atg3 with wild-type or mutant forms of the amphipathic helix was introduced into Atg3−/− MEFs by lentiviral infection and rescue of the three phenotypes was tested. (a) Immunoblot analysis of LC3-II, GL2-II and GABARAP-II formation. GABARAP lipidation is significantly observed only in the presence of bafilomycin A1 (BafA1: 100 nM). Asterisk indicates a nonspecific band recognized by the Atg3 antibody.(b) Cells were infected as in a and transduced cells were selected with puromycin for 1-2 days before starvation and immunolabelling with the anti-LC3B antibody. Representative images are shown in b(c) The number of LC3 puncta per cell was counted manually from 22-96 cells per replicate. Raw data can be found in Supplementary Fig. 5. P values represent difference from vector negative control. n = 2-5 independent experiments; the precise n values and number of cells per experiment are listed in the Methods.d) Cells as in b were kept in full media before being subjected to fixation and immunolabelling with the anti-Atg16L antibody. Atg16L puncta area as a fraction of total cellular area was obtained as described in Methods. This ratio was plotted as arbitrary units. Grey dashed line indicates the value for Atg3−/− cells rescued with wild-type Atg3. n = 2 (for V15K) or 3 (for all others) independent experiments; the precise n values and number of fields visualized per experiment are listed in the Methods. Raw data can be found in Supplementary Fig. 4. Atg3 variants that support lipidation of LC3 family proteins in vitro (Fig. 5) are indicated with black bars, while those that do not support lipidation are indicated with white bars. P values represent difference from wild-type rescue. **P 0.1; *P 0.05. Error bars in c,d represent s.d. for all samples of n > 2. Uncropped versions of all gels are included in Supplementary Fig. 7.
Figure 1E Reproducibility of 2 independent experiments - correlation of observed changes in expression. Blue line indicates the linear fit with shaded areas as confidence intervals.
Figure 2A Number of target genes identified using differential expression for each assayed TF. *genes identified as essential for self-renewal of Hoxb8-FL cells either in (Basilico et al, 2020).
Figure 3A A representation of the pairwise degree of overlap in targets (size of the circle) and correlation in gene expression changes (colour) among overlapping targets for indicated TF perturbations. Red indicates positive correlations and blue negative correlations.D Identification of target gene modules - groups of genes with common regulatory patterns by TFs. Colour indicates the fold change (adjusted for significance) of gene expression following each TF perturbation. Rows (perturbed TFs) and columns (target genes) are hierarchically clustered. 44 modules for target genes are shown. Below examples. Selected modules with highlighted overall regulation pattern and example genes listed below.
Figure 4D Changes in expression for genes co-regulated by separate Cebpa/Meis1/Spi1 and Hoxb8 perturbations (FDR <0.1 and |log2(FoldChange)| > 0.2). The interaction row indicates changes beyond simple additive effect (white = additive effect). Each gene was annotated with an interaction class (int. class) as explained in (C), using the |log2(FoldChange)| > 0.2) threshold to assign change direction. E Fractions of genes in each interaction class showed in (D).
Figure 5A Dice scores summarising overlaps among peaks identified for 14 ChIP experiments in Hoxb8-FL cells.B Comparison of genes identified as differentially expressed following TF loss with mapped ChIP peaks in a corresponding experiment. Enrichment over a random value and the p-value (based on the hypergeometric test) are shown (bars corresponding to non-significant enrichment values are semi-transparent). Analysis was performed separately for genes up- and down-regulated.C, D Genomic views of relevant TF binding to Cebpa and Gata3 loci (supporting direct regulatory interactions identified in Figs 3A,B,C). The red arrow indicates a putative enhancer element, which is bound by Ebf1 and flanked by AcK27-rich regions.
Figure 6C Correlation in gene expression changes following Ebf1 and Gata3 loss in Hoxb8-FL cells. Each quadrant corresponds to a set of target genes with a common regulation by Gata3/Ebf1 - I - inhibition/inhibition, II - activation/inhibition, III - activation/activation, IV - inhibition/activation. For each group the sums of scaled expression values in mouse LK/LSK or human BMMC landscapes is plotted to highlight cell types with the highest overall expression. For landscape annotation see Fig 7B andE.. Changes in expression for example genes are provided in Appendix Fig 2G-J. Blue line indicates the linear fit with shaded areas as confidence intervals.E Correlation in expression changes after 24h following Ebf1 loss in Hoxb8-FL cells and re-expression of Ebf1 in Ebf1-/- pre-pro B cells (Li et al, 2018). Blue line indicates the linear fit with shaded areas as confidence intervals.F, G Expression of the key marker genes (F) and Ebf1, Pax5, Gata3, Cebpa factors (G) along pseudotime corresponding to the B-cell differentiation trajectory in human foetal liver cells, data from (Popescu et al, 2019).
Figure 1D. Relative FCR activities in the roots of wild-type plants and photoreceptor mutants grown under white light with either Fe-sufficient (20 µM, +Fe) or Fe-deficient (2 µM, -Fe) conditions for 7 d.
Figure 2D-F. Fe contents of whole plants, FER expression in roots and relative FCR activities in the roots of plants grown under Fe-sufficient (20 µM, +Fe) or Fe-deficient (2 µM, -Fe) conditions for 7 d. Plants were exposed to high (H-, 2.0) or low (L-, 0.5) red (R) to far red (FR) ratios.
Figure 3C. Accumulation of HY5 protein in leaves and roots of reciprocal grafts of phyB and WT plants grown under white light (200 µmol m-2s-1) for 7 d. Rubisco and β-Actin were used as loading controls for leaves and roots in the western blot analysis, respectively. The values shown above each lane indicate the relative abundance of the HY5 protein. D. Accumulation of HY5 protein in the roots of WT and phyB plants under high (H, 2.0) or low ratio of (L, 0.5) red (R) to far red (FR) light conditions. β-Actin was used as loading controls in the western blot analysis. The values shown above each lane indicate the relative abundance of the HY5 protein.
Figure 4D. Fe content of whole plants. WT and hy5 plants were grown under high (H) or low ratios of (L) red (R) to far red (FR) light conditions with either Fe-sufficient (20 µM, +Fe) or Fe-deficient (2 µM, -Fe) conditions for 7 d.E. FER expression in roots. WT and hy5 plants were grown under high (H) or low ratios of (L) red (R) to far red (FR) light conditions with either Fe-sufficient (20 µM, +Fe) or Fe-deficient (2 µM, -Fe) conditions for 7 d.
Figure 5E. Direct binding of HY5 to the FER promoter analyzed using ChIP-qPCR in 35S-HY5-3HA-overexpressing (HY5-OE) tomato plants. WT and HY5-OE plants were exposed to white light (200 µmol m-2s-1) grown under Fe-deficient (2 µM, -Fe) conditions for 7 d. Input chromatin was isolated from root samples at 7 d. The epitope-tagged HY5-chromatin complex was immunoprecipitated with an anti-HA antibody. A control reaction was processed side-by-side using mouse IgG. Input- and ChIP-DNA samples were quantified by RT-qPCR using primers specific for the promoter and exon fragment of the FER gene as indicated in (D). The ChIP results are presented as percentage of the input DNA.
Figure 6A-C. Fe content of whole plants (A) and the photochemical efficiencies of PSI and PSII [Y(I) and Y(II)] (B and C) in young leaves of grafted tomato plants with grafts between WT/WT and WT/fer grown under H-R/FR (2.0) or L-R/FR (0.5) conditions for 7 d.D-F. Transcript levels of FER, FRO1 and IRT1 in the roots of grafted tomato plants with grafts between WT/WT and WT/fer grown under H-R/FR (2.0) or L-R/FR (0.5) conditions for 7 d.
Figure 7B. The abundance of FER transcripts in the roots of WT and phyB plants grown under 20 μM Fe-EDTA in nutrient solution in a growth room.D. Fe content in the fruits of WT and phyB plants. Plants were grown in soil in a greenhouse.
Figure 11D 1H-NMR spectra of a metabolite mix and the individual metabolites contained therein. Identification of single compound peaks from 1D 1H-NMR spectra of a metabolite mix. Compound detection is exemplified by showing sections of the 1D 1H-NMR spectra of ATP, IMP, proline (PRO), malate (MAL), shikimate (SKM) and methionine (MET).
Figure 5Relative activity of NADP+-dependent glucose-6-phosphate dehydrogenase in the presence of potential regulators, error bars represent the s.e.m.. All regulators were tested at two concentrations in four distinct replicates (n=4, ATP: 5mM, 18 mM; GTP: 2 mM, 10 mM; IMP and AMP: 1 mM, 5 mM), the asterisk denotes significant inhibition (18 mM ATP: p-value = 0.029, 10 mM GTP: p-value = 0.025, one-tailed t-test).Relative activity of phosphate acetyltransferase in the presence of phenylpyruvate and tryptophan, error bars represent the s.e.m.. All regulators were tested at three concentrations in three distinct replicates (n=3, phenylpyruvate: 0.1, 1, 5 mM, L-tryptophan: 0.1, 1, 4.4 mM).Relative activity of fructose-bisphosphate aldolase class II in the presence of 5 mM of potential regulators, except hypoxanthine, which was tested at 3.22 mM. All regulators were tested in three distinct replicates (n=3), error bars represent the s.e.m.. The asterisk denotes significant activation (5 mM 3PG: p-value = 0.025, 5 mM ATP: p-value = 0.024, 5 mM PEP: p-value = 0.046, one-tailed t-test).
Figure 1B C99-Bpa constructs remain essentially cleavage-competent. Numbers denote the relative γ-secretase cleavage efficiencies of C99-Bpa substrates as calculated from the AICD/C99-Bpa ratios relative to that of WT C99, which was set to 1. Inefficiently cleaved substrates (cleavage efficiency below 20%) were mostly found for Bpa substitutions in extramembraneous domains. Specificity of substrate cleavage was confirmed by inhibition of AICD formation in the presence of L-685,458. Residues of the TMD are highlighted in orange here and elsewhere where appropriate.C Values obtained in (B) were additionally plotted. Yellow line indicates the cleavage efficiency of WT C99, which was set to 1. ECD, extracellular domain; ICD, intracellular domain.
Figure 2B Identification of C99 interaction sites with γ-secretase. C99-Bpa substrates were irradiated with UV light in the presence of CHAPSO-solubilized γ-secretase. Crosslinked substrates were captured by Ni-NTA affinity pulldown and bound subunits were identified by a ~10 kDa molecular weight increase compared to the input. Results are shown for the major substrate crosslinking residues. Crosslink formation was not observed in the absence of UV irradiation or in the presence of Triton X-100, which dissociates the γ-secretase complex, proving crosslink specificity. Bracket indicates the molecular weight range of putative C99-APH-1 crosslink bands. APH-1aL, long splice variant of APH-1a.C Excess amounts of parental C99 WT substrate compete crosslinking of C99-Bpa substrates to γ-secretase. Single and double asterisks indicate antibody crossreactivities to C99 monomer and dimer, respectively.
Figure 3Quantitative crosslinking analysis revealed V44, L49, M51 and L52 as major interactions sites of C99 with γ-secretase with high crosslinking efficiencies ranging from ~2-8% of input. While the PS1 NTF was bound by C99 over nearly the whole range of residues, only very few residues bound to PS1 CTF. Several residues in the substrate N-terminal extracellular domain bound to NCT. PEN-2-binding residues clustered in the membrane-flanking extracellular and intracellular domains of C99.