EMBO/SourceData huggingface dataset:
Figure 2Confocal microscopy reveals robust recruitment of βarr1 to B2R mutant constructs upon agonist-stimulation. HEK-293 cells expressing either B2RWT or B2R mutants along with βarr1-mCherry were stimulated with agonist (Bradykinin; 100nM) and the localization of βarr1 was visualized using confocal microscopy. Representative images from three independent experiments are shown here, and the scale bar is 10μm. Visual scoring from three independent experiments revealed agonist-induced βarr1 recruitment (i.e. membrane and endosomal localization) in approximately 75% of the cells for B2RWT (662 cells), 74% of the cells for B2RΔG368 (169 cells), 75% of the cells for B2RL370T (130 cells), 85% of the cells for B2RΔG368+L370T (132 cells) and 77% of the cells for B2RΔI374 (116 cells).HEK-293 cells expressing B2R constructs with C-terminal SmBiT and βarr1 with N-terminal LgBiT were treated with indicated concentrations of bradykinin, and ligand-induced change in luminescent signal was measured. Concentration-response curves were plotted using GraphPad Prism, and pEC50 (top) and Emax (bottom) were calculated. Data represent mean ± SEM of five independent experiments (three for B2RΔI374), each performed in duplicate.
Figure 5HEK-293 cells expressing the indicated receptor constructs (pcDNA vector control for mock-transfection) together with βarr1-SmBiT and LgBiT-Ib30 were stimulated with the indicated concentrations of respective agonists for 10min. Subsequently, the luminescence signal generated upon the interaction of βarr1-SmBiT and LgBiT-Ib30 was measured, normalized with basal signal (i.e. no agonist stimulation treated as 1), and plotted using GraphPad Prism. pEC50 (top) and Emax (bottom) values are mentioned in the respective graphs and data represent mean±SEM of four independent experiments, each carried out in duplicate.HEK-293 cells expressing the NanoBiT-Gq protein and indicated B2R constructs were treated different concentrations of bradykinin, and ligand-induced change in luminescent signal was measured. Concentration-response curves were plotted using GraphPad Prism to calculate pEC50 (top) and Emax(bottom) values included in the graph. Data represent mean±SEM of three independent experiments with each performed in duplicate, and normalized with respect to the luminescence signal under basal (no-agonist treatment) condition (treated as 1).
Figure 7HEK-293 cells expressing the indicated AT1aR constructs, in absence (CTL; control) or presence of βarr1 knock-down (βarr1-KD) were stimulated with indicated concentrations of angiotensin II (AngII) for 10 min. Subsequently, ERK1/2 phosphorylation was measured by Western blotting and signal intensities were quantified using densitometry and presented as bar graphs. Data were normalized with respect to the signal at 100nM agonist concentration in control cells (treated as 100%) and represent mean±SEM of five independent experiments. Data were analyzed using Two-way-ANOVA with Bonferroni multiple comparisons test (***p<0.001, p<0.05).HEK-293 cells expressing the indicated AT1aR constructs, in absence (CTL; control) or presence of βarr1 knock-down (βarr1-KD) were stimulated with indicated concentrations of angiotensin II (AngII) for 10 min. Subsequently, ERK1/2 phosphorylation was measured by Western blotting and signal intensities were quantified using densitometry and presented as bar graphs. Data were normalized with respect to the signal at 100nM agonist concentration in control cells (treated as 100%) and represent mean±SEM of five (six for AT1aRΔL337) independent experiments. Data were analyzed using Two-way-ANOVA with Bonferroni multiple comparisons test (***p<0.001, p<0.05).
Figure 1G. Endogenous MITOL enhances the K48-polyubiquitin chains of Parkin. WT or MITOL KO HeLa cells stably expressing HA-Parkin were treated with CCCP (10 µM) for indicated time. MG132 (30 μM) was added 3 h after CCCP treatment. Lysates of cells were fractionated into cytosolic, mitochondrial and ER fractions, and then subjected to an IP-IB assay with the indicated antibodies. K48-polyubiquitin chains were immunoblotted with K48-specific ubiquitin antibody.
Figure 2E. MITOL regulates mitophagy. MITOL WT HeLa cells, MITOL KO HeLa cells and KO HeLa cells transfected with MITOL WT plasmids 0.5µg (+) and 5µg (++) stably expressing HA‐Parkin and mt‐Keima were treated with CCCP (10µM) for 8h. Then, mKeima was measured at 488 (pH 7) and 561 (pH 4) nm lasers using Flow Cytometer. Percentages of mitophagy were calculated from 30,000 cells in each independent experiment. Data represent the mean ± SD of three independent experiments. For statistical analysis, a one-way ANOVA with Tukey post-test was performed, **P < 0.01.
Figure 3C. Endogenous MITOL translocates to the ER in later phase of mitophagy. EGFP-MITOL knock in HeLa cells were transfected with HA-Parkin and treated with DMSO or CCCP (10 µM) as indicated times. Cells were fixed, permeabilized and subjected to immunofluorescence analysis with the indicated antibodies. Colocalization was quantified by Manders's coefficient. Means ± SEM of more than 10 cells obtained from three independent experiments. For statistical analysis, a one-way ANOVA with Tukey's multiple comparisons test were performed, ****P < 0.0001. Scale bar represents 1 μm.E. ER-localized MITOL is transported from the mitochondria, and is not newly synthesized protein. HeLa cells stably expressing HA-Parkin were co-transfected with vectors for MITOL-KikGR and FLAG-FKBP38. After ultraviolet light (365 nm) exposure to the whole plate, cells were incubated with or without CCCP (10 µM) for indicated time, and monitored for red and green KikGR fluorescence. Scale bar, 10 μm. Higher magnification images of the boxed regions are shown in the small panel. Right panel is schematic experimental model for KikGR in this study.
Figure 4C. Phosphorylated Parkin accumulates in the ER fraction in the absence of MITOL. WT or MITOL KO HeLa cells stably expressing HA-Parkin were treated with DMSO or CCCP (10 µM) for 48 h. Lysates of cells were fractionated into cytosolic, mitochondrial and ER fractions, and then subjected to an IB assay with the indicated antibodies. Phospho-Ser65-Parkin is detected by using specific antibody. Right panels are the quantification of IB about Phospho-Ser65-Parkin protein levels of the ER fraction. The data represent the mean ± SD for three independent experiments. For statistical analysis, a one-way ANOVA with Tukey post-test was performed, **P < 0.01.D. Parkin is detected at the ER in the absence of MITOL. HeLa cells were transfected with vectors for KikGR-Parkin. After ultraviolet light (365 nm) exposure to the whole plate, cells were incubated with or without CCCP (10 µM) for indicated time, and monitored for red and green KikGR fluorescence. Scale bar, 10 μm. Higher magnification images of the boxed regions are shown in the small panel.
Figure 5D. MITOL KO increases degradation of ER targeting FKBP38. HeLa cells stably expressing HA-Parkin were transfected with mitochondrial targeting FLAG-FKBP38 (FKBP38ActA) and ER targeting FLAG-FKBP38 (FKBP38IYFFT), and treated with DMSO or CCCP (10 µM) for 24 h. Lysates of cells were subjected to an IB assay with FLAG antibodies for organelle targeting FKBP38 or indicated antibodies. Another cell lysates were subsequently separated on a Phos-tag gel, followed by IB with anti-Parkin antibodies (Phos-tag).E-G. MITOL partly prevents CCCP-induced cell death by reducing Parkin-mediated degradation of FKBP38. WT or MITOL KO HeLa cells stably expressing HA-Parkin and HeLa cells were transfected with the indicated vectors, and treated with DMSO or CCCP (10 µM) for 24 h. Cells were stained with propidium iodide (PI) for counting the percentage of dead cells using fluorescence microscopy. Data represent the mean ± SD of five independent experiments (>100 individual cells were counted). For statistical analysis, a one-way ANOVA with Tukey post-test was performed, **P < 0.01. KR, FKBP38 K271/273R.
Figure 6A. Mislocalization of Bcl-2 is observed in MITOL KO cells in mitophagy. WT or MITOL KO HeLa cells stably expressing HA-Parkin were transfected with FLAG-Bcl2 and treated with DMSO or CCCP (10 µM) for the indicated times. Cells were immunostained with indicated antibody. Scale bar, 1 μm.B. MITOL prevents caspase-dependent cell death in mitophagy. WT or MITOL KO HeLa cells stably expressing HA-Parkin and HeLa cells were treated with DMSO or CCCP (10 µM) with or without Z-VAD-FMK (10 μM) for 24 h. Cells were stained with propidium iodide (PI) for counting fluorescence microscopy of the percentage of dead cells. Data represent the mean ± SD of three independent experiments (>100 individual cells were counted). For statistical analysis, a one-way ANOVA with Tukey post-test was performed, **P < 0.01. C. Cell death in mitophagy caused by MITOL deficiency depends on calcium leak. WT and MITOL KO HeLa cells stably expressing HA-Parkin or HeLa cells were treated with DMSO or CCCP (10 µM) with or without BAPTA-AM (10 μM) for 24 h. Cells were stained with propidium iodide (PI) for counting fluorescence microscopy of the percentage of dead cells. Data represent the mean ± SD of three independent experiments (>100 individual cells were counted). For statistical analysis, a one-way ANOVA with Tukey post-test was performed, **P < 0.01.
Figure 1(C) Expression of miRNAs miR-146a and miR-505 correlated with overall survival in ovarian cancer patients. The validation cohort (n=150 samples) is shown. See Figure EV1 for the training cohort.
Figure 2(A) The consequence of miR-155 and miR-181b mimics on cell viability, 5 days post transfection, relative to a negative control miRNA mimic is shown across a panel of normal and ovarian cancer cell lines as indicated. Each data point is the mean of n=3/cell line. In the screen, miR-155 was found to reduce cell viability (Z-score < -2) in one cell line, and TCGA expression data revealed no significant change in expression of this miRNA in ovarian tumors. miR-181 was found to reduce viability (Z-score < -2) in 2 cell lines, and TCGA expression data revealed no significant change in expression of this miRNA in ovarian tumors. N, normal cell lines (IHH, HOSE, HBEC3, HBEC13, HBEC30, and HBEC34), EOC, epithelial ovarian cancer cell lines. miR-155 data points for each cell line are shown in black while miR-181b data points are displayed in red.(B) Immunoblots indicate suppression of serum-induced AKT phosphorylation at S473 and T308 in response to miR-155 and suppression of T308 phosphorylation in response to miR-181b.(C) miR-155 and miR-181b reduced cell viability in GDC0941-sensitive breast cancer cell lines. Error bars indicate mean ± SD (n=3).(D) Differential localization of E-cadherin in PEO1 and PEO4 cells 48 hours post transfection with the indicated oligos. Cells were counterstained with phalloidin and DAPI.(E) Stimulation of PEO4 cells with 10 ng/mL TGFβ1 significantly sensitized the cells to AKT inhibition with AKT Inhibitor X. Each point represents the mean of 3 experiments ± SD and * denotes p-value < 0.05 by Student's T-test.(F) Cell viability upon expression of miR-155 or miR-181a mimics in 41 NSCLC cell lines and 5 human bronchial epithelial cell lines. Each data point is the mean of n=3/cell line. R2 from Pearson correlation.
Figure 3(A) Consequence of miR-517a on EOC cell viability and 41 NSCLC cell lines (as in 2A). N, normal cell lines (IHH, HOSE, HBEC3, HBEC13, HBEC30, and HBEC34). miR-517a was found to significantly reduce cell viability (Z-score < -2) in 5 cell lines in the screen, and TCGA expression data revealed no significant change in expression of this miRNA in ovarian tumors.(B, C) In vivo delivery of neutral liposome incorporated miR-517a mimic reduced tumor burden by weight (B) and nodule number (C) in an orthotopic xenograft model using SKOV3 cells. Box-and-whisker plot from n=8. p-value from Student's T-Test. LD, low-dose (200 μg/kg); HD, high-dose (400 μg/kg).(D) Correlation of the consequence of ARCN1 depletion and miR-517a sensitivity in 12 NSCLC cell lines (plot as in 2D).(E) Immunoblots indicate miR-517a-induced depletion of ARCN1 and USP1 in the indicated cell lines.(F) Consequence of the indicated siRNAs and miR-517a on the viability of the indicated cell lines.(G) Immunoblots indicate that miR-517a suppresses expression of ARCN1 in multiple miR-517a sensitive cell lines.
Figure 4(A) Consequence of miR-124 on EOC cell viability (as in 2A). N, normal cell lines (IHH and HOSE). In the screen, miR-124 was found to significantly reduce cell viability (Z-score < -2) in 6 cell lines, and TCGA expression data revealed no significant change in expression of this miRNA in ovarian tumors.(B) miR-124 induced expression of neuronal marker proteins Tuj1 (TUBB3) and MAP2 in ES2 cells 48 hours post transfection. Cells were counterstained with DAPI and phalloidin.(C) miR-124 responsive genes in PEO1 cells were enriched for TargetScan predicted targets. p-value from hypergeometric distribution.
Figure 5(A) Immunoblots indicate miR-124-induced SIX4 depletion. siSIX4 is shown as an antibody control.(B) Consequence of SIX4 depletion on EOCcell viability (as in 2A, N, normal cell lines: HOSE, HBEC30).(C) in vivo knockdown of SIX4 using neutral liposome incorporated siRNA reduced tumor burden and ascites volume in an orthotopic xenograft mouse model. Box-and-whisker plot from n=8. p-value from Student's T-Test.(D) Consequence of SIX4 depletion in PEO1 cells on E-cadherinplasma membrane accumulation 48 hours after transfection. Cells were counterstained with phalloidin and DAPI.(E) Immunoblots indicate consequence of SIX4 depletion on LKB1 accumulation and AMPK pathway activation.
Figure 1ER Proliferation under UPR-Inducing Conditions(A) Determination of ER abundance in control and UPR-induced cells. Representative cells are shown. The UPR was induced in wild-type cells by addition of DTT. Ultrastructure of control cells and UPR-induced cells was analyzed using ImageJ. The lower images show traces of cortical ER (represented in magenta) and the nuclear envelope (NE, in blue). Vacuoles, nuclei, and mitochondria are indicated as V, N, and M, respectively.(B) Quantification of the ER proliferation during the UPR. UPR was induced and cells were collected for EM at the indicated time points. Length of the ER (as traced in [A]) was measured and divided by the area of the section. Data are plotted relative to time 0. Measurements for each time point correspond to the mean of 25 independent cell images.(C) Expression of HAC1i was induced by addition of 100 μM DOC for 3 h. ER was quantified as described above in (B).
Figure 2The ER Morphologically Changes during the UPR(A) Control cells and UPR-induced cells were used to analyze and follow the ER within a single cell using EM. Boxes indicate the areas magnified in (B). Cells shown here correspond to the full section of the images labeled "+140 nm" in (B).(B) Serial section of control and UPR-induced cells. Sections are separated by 70 nm on the z-axis. ER is represented in magenta and NE in blue.(C) Electro micrographs from control and UPR-induced cells showing that the distance between ER membranes increases during the UPR. For a better preservation of the ultrastructure, samples for this experiment were prepared using high-pressure freezing/freeze substitution techniques (see Material and Methods).
Figure 3Characterization of ER-Containing Autophagosomes (ERAs) during the UPR(A) Images of representative DTT-treated wild-type cells that contain ERAs. Nuclei and cytoplasm are indicated as N and C, respectively.(B) Enlargement of representative images of ERAs from different cells. The bottom right image is likely to show a section through a cup-shaped ERA. Note that there are no connections between the stacked cisternae and the envelope.(C) High magnification of the ERA double membrane envelope.(D) Some ERAs are found attached to or are in close proximity to ER tubules/sheets (indicated by the arrow). Note that the section in (A) includes two such junctions.(E) High-pressure freezing/freeze substitution image of an ERA linked to an ER tubule/sheet. The osmium/lead staining used in this technique visualizes ribosomes and demonstrates that the outer ERA envelope membrane, but not the stacked internal cisternae, are tightly studded with ribosomes, indicating that they originate from ER membranes.(F) High-pressure freezing/freeze substitution image of an ER-ERA junction using an improved protocol to visualize membranes.(G) Using the same technique as in (F), we visualized the internal membrane content of an ERA. Note that both portions of the internal membranes and of the sequestering double membrane envelope contain bound ribosomes, and hence are likely derived from the ER.
Figure 4Fluorescence Visualization of an ER Marker after UPR Induction(A) Cells treated with the UPR-inducing drug DTT (+DTT) or with no drug were visualized using a fusion protein between the translocon component Sec61 and the red-fluorescent protein "cherry." Top panels show untreated cells, and bottom panels show representative UPR-induced cells.(B) Representative images showing UPR-induced cells that contain ERAs (indicated by arrows).
Figure 5Immunogold Labeling of ERAs with an Antibody Directed against an ER Membrane Marker(A) Representative section of a cell immunolabeled against a myc-tagged Sec63, an integral ER membrane protein. As a primary antibody, we used a rabbit polyclonal anti-myc and, as a secondary, we used 15-nm gold particles-conjugated anti-rabbit antibody. Nucleus, nuclear envelope, ER, and ERA are indicated as N, NE, ER, and ERA, respectively.(B) High magnification of an electron micrograph of a section of ER. Quantification showed that there are 5 ± 2 gold particles per linear micrometer of ER.(C) High magnification of ERAs. To predict how many gold particles one should expect in a particular ERA, we first calculated and averaged the amount of ER (expressed as length in linear micrometers) present in an ERA (similar to the ones shown in Figure 3B), and normalized the value for its area. These calculations determined that there are 20.8 ± 3.3 μm of ER per μm2 inside the ERAs. These values allowed us to predict how many gold particles would be expected over a section of an ERA if it were packed with ER membranes. Two representative ERAs are shown. The ERA shown in the middle picture should hold 2.4 μm of ER inside and, therefore, should have 12 gold particles. We counted 12 gold particles. The ERA on the right could contain 2.7 μm of ER and should contain14 gold particles; we counted 16 gold particles. The image on the right shows a representative view of a nucleoplasmic region.(D) Quantification of gold-labeling density per area. To assess the signal-to-noise ratio of our immunogold-labeling procedure, we assessed background labeling by counting the number of gold particles over an areas of nucleoplasm (N) and over ERAs, and normalized the counts to the respective areas.
Figure 6(A) Wild-type cells transformed with a plasmid containing GFP-Atg8 were grown for 4 h in synthetic media with no drug, with UPR-inducing conditions (+DTT and +TM), or under nitrogen starvation conditions (N starv), and then harvested for protein preparation. Protein extracts were analyzed by Western blotting using antibodies against GFP (top panel) or Hac1 (bottom panel). Total protein concentration was measured by BCA protein assay. Same concentration of protein was loaded in each lane, and transfer efficiency was checked by Ponceau staining. The identities of the different bands are indicated.(B) Wild-type cells expressing GFP-Atg8 grown under the conditions described above were visualized by fluorescence microscopy.(C) GFP-Atg8 was detected in extracts from untreated hac1Δ cells or cells expressing HAC1i (+DOC) by Western blotting using antibodies against GFP.(D) Western blot using antibodies against GFP of extracts from hac1Δ, ire1Δ, or vps4Δ pep4Δ cells expressing GFP-Atg8. Mutant cells were grown under regular conditions, UPR-inducing conditions (+DTT), or nitrogen starvation conditions (N starv).
Figure 7Localization of GFP-Atg8 during UPR InductionSome of the DTT-treated cells shown in Figure 4B expressing GFP-Atg8 and Sec61-cherry (as an ER marker) were visualized using fluorescence microscopy. GFP-Atg8 localizes in close proximity to the ERAs detected by the ER marker.
Figure 8Atg8 and Other ATG Genes Are Necessary during UPR InductionSerial dilutions for wild-type, hac1Δ, atg1Δ, atg8Δ, atg9Δ, atg16Δ, and atg20Δ deletion cells and vps4Δ pep4Δ double deletion cells were grown on rich-media plates with no drug (YPD) or with different concentrations of tunicamycin (TM; 0.2 or 1.0 μg/ml). atg19Δ gave an identical result to the other autophagy genes shown here (unpublished data).
Figure 1A Left: Overlay image of a confocal recording of an apoptotic U2OS cell surrounded by non-apoptotic cells labeled with Bax (green) and Tom22 (red). Bax translocates to the mitochondria in apoptotic cells. Right: Individual display of the two color channels as shown in the overlay image. The asterisk denotes the apoptotic cell. Scale bars: 10 µm.B, C Dual color image of an apoptotic U2OS cell decorated with antibodies against Bax (green) and Tom20 (red). The Bax signal was recorded in the STED mode and the Tom20 signal in the diffraction-limited confocal mode. (B) and (C) display the same data set. The small images are magnifications of the areas indicated by the rectangles. In (B) the color table was adjusted to the brightest Bax signal in the image resulting in a clear display of the clusters. In (C) the color table was adjusted such that the dimmer Bax-rings are visible and the clusters are saturated. The arrows point to Bax-rings. Scale bars: 1 µm.D Optical sections of an apoptotic mitochondrion labelled for Bax (green) and Tom22 (red). Shown are three optical sections and a maximum intensity projection of the entire image stack. Scale bar: 0.5µm.E Bax-rings on apoptotic mitochondria of various mammalian cell types. Shown are apoptotic mitochondria labelled for Bax (green) and Tom22 (red) in HT1080, SH-SY5Y, HeLa and CV-1 cells, as indicated. Scale bars: 0.5 µm.F Quantification of the diameter of Bax-rings in apoptotic U2OS cells. Only the long ring-axis was measured. Bax-rings smaller than 200 nm exist, but were not considered.
Figure 2Apoptotic mitochondria were decorated with antibodies against Bax (green) and Tom22 (red). The Bax signal was recorded in the STED mode. Shown are the individual color channels as well as an overlay (from top to bottom) of several apoptotic mitochondria. We used Lagrange interpolation to double the number of pixels. Note that throughout this manuscript except for contrast stretching no image manipulation was applied. Scale bar: 0.5 µm.
Figure 3A, B Three-color images of mitochondria of unchallenged (A) and apoptotic (B) U2OS cells. From left to right: Tom22, Bax (recorded in the STED-mode), cytochrome c and an overlay of all three channels. The arrows denote Bax-rings. Scale bars: 2 µm.
Figure 4A In apoptotic Drp1 knockdown U2OS cells, cytochrome c release is delayed. Confocal overview image of an apoptotic Drp1 knockdown cell labelled with antibodies against Tom20 (red), cytochrome c (blue) and Bax (green). Large image: Overlay of all three channels. Small images: Magnifications of the area indicated by the rectangle in the large image. Shown are the individual channels, as indicated. The arrows point to mitochondria that had not released cytochrome c; the asterisks denote mitochondria that had released cytochrome c. Scale bars: 10 µm (overview) and 2 µm (magnifications).B In Drp1 knockdown cells Bax-ring formation and cytochrome c release is not correlated. Three-color images of apoptotic mitochondria of Drp1 knockdown cells. From left to right: Tom22, Bax (recorded in the STED-mode), cytochrome c and an overlay of all three channels. The arrows point to Bax-rings. Scale bar: 1 µm.