Fig. 3: Constrictions within Ringo mitochondria are mediated by Dnm1 but do not require contacts with the ER.

a SIM of WT cells labeled for Tom70-mcherry and Dnm1-GFP (top) or Mmm1-GFP (bottom) in fermentation (YPD) or respiration (YPG). Scale bar, 2 µm. Right graphs: Dnm1 (top) and Mmm1 (bottom) puncta count per cell ( > 51 for Dnm1; > 77 for Mmm1) in YPD or YPG. *p = 0.0109, ns p = 0.6582 (Two-tailed unpaired t test). b Total protein extracts prepared from WT and dnm1Δ (top) or MMM1-GFP (bottom) cells in YPD or YPG and analyzed by immunoblotting as indicated. MW (kDa) indicated on the right. c Quantification of Dnm1-GFP (top) or Mmm1-GFP (bottom) puncta count/area of Tom70-mCherry from cells ( > 50 cells per experiment) in (a). *p = 0.014, ns p = 0.6056 (Two-tailed unpaired t test). d SIM Time-lapse from Dnm1-mcherry, Mmm1-GFP, mitotracker (grey) triple-labeled cells during fermentation and respiration. Green arrows indicate fission events. e Percentage of total fission events positive or negative for both Dnm1 and/or Mmm1 (> 79 fission events per experiment). ns p = 0.9946, ns p = 0.9964, ns p = 0.8602, ns p > 0.9999 (Two-way Anova followed by Tukey’s multiple comparisons test). f Percentage of Dnm1 (left) or Mmm1 (right) localization at non-constrictions (purple) or constriction (blue) sites in cells ( > 76 cells per experiment) from (a). ***p = 0.0007, ***p = 0.0007, ns p = 0.0930, ns p = 0.0839 (Two-way Anova followed by Tukey’s multiple comparisons test). For all graphs, Mean ± s.d. from n = 3 independent experiments (circles and dots). ns, not significant.