Fig. 4: sisR-1 regulates p62-mediated mitophagy via polyubiquitination of VDAC1.
From: Nutrient-dependent regulation of a stable intron modulates germline mitochondrial quality control
A A drawing of p62-mediated mitophagy. B Confocal images showing localizations of sisR-1 (Green), p62 (Red), ATP5α (Magenta) and DAPI (Blue) in fasted Oregon R. n = 3 biological replicates. Scale bar = 10 µm. C Stacked bar graph showing the percentages of ATP5α-positive mitochondrial clumps that colocalize with sisR-1, p62 or both sisR-1 and p62. D Western blots showing levels of p62 in insoluble fractions extracted from ovaries of fed and fasted Oregon R and sisR-1 line 1 flies. E, F Graphs showing the relative levels of insoluble p62 in fed and fasted Oregon R and sisR-1 RNAi line 1, as shown in the blot in D. Data are presented as mean values +/−SD from four biological replicates. *p < 0.05. Two-tailed t-test. G Model on the effects of Park on ubiquitination of VDAC1 affecting p62-mediated mitophagy of defective mitochondria. H Western blots showing mono- and poly-ubiquitination of VDAC1 in fed and fasted Oregon R and fasted sisR-1 RNAi line 1 against control β-Tubulin. n = 2 biological replicates. I Chart showing the percentages of stage 8/9 egg chambers with mitochondrial clumps in fasted Oregon R, VDAC1-WT overexpression, VDAC1-K273R overexpression, VDAC1-poly-KR overexpression and Parkin overexpression ovaries. n = 30 (Oregon R), 37 (WT), 35 (K273R), 30 (poly-KR), 24 (Park OE). egg chambers counted. *p < 0.05. ns not significant. Chi-square test, one-sided. J Chart showing the average numbers of mitochondrial clumps present per stage 8/9 egg chamber that contain clumps in fasted Oregon R, VDAC1-WT overexpression, VDAC1-K273R overexpression, VDAC1-poly-KR overexpression and Parkin overexpression ovaries. Data are presented as mean values +/−SD. *p < 0.001. n = 30 (Oregon R), 37 (WT), 35 (K273R), 30 (poly-KR), 24 (Park OE). egg chambers counted. Two-tailed t-test. K Confocal images of ATP5α localization in fasted Oregon R, VDAC1-WT overexpression, VDAC1-K273R overexpression, VDAC1-poly-KR overexpression and Parkin overexpression ovaries Arrowheads point to mitochondrial clumps. n = 3 biological replicates. Scale bar = 20 µm. Source data are provided as a Source Data file.
