Formation of MiD51 foci is dependent on Drp1. (A) MiD51^TALEN MEFs expressing GFP-tagged Miro1, MiD51, MiD51^NBD, MiD51^ΔPEYFP, MiD51^R234A, or MiD51^R235A (green) were fixed and immunostained for Drp1 (red). Merged images show the absence or presence of foci at mitochondria. Bars, 10 µm. (B) Wild-type (WT) and Drp1^−/− MEFs were transfected with MiD51-GFP (green) and fixed and immunostained for Tom20 (red). Bars: (merge) 20 µm; (inset) 5 µm. Dashed boxes represent insets shown in the far right panel. (C) Time-lapse imaging series of COS-7 cells transfected with MiD51-GFP (green) and stained for mitochondria with MitoTracker deep red. Arrowheads indicate the site of a fission event. Bar, 2 µm.