Transfer of Drp1 punctae from ER to mitochondria. (A) Three-color time-lapse images of live GFP-Drp1-KI cell expressing mCherry-mito7 (mitochondria, red), eBFP2-peroxisome (peroxisome, blue), and Drp1 in green. An independent Drp1 puncta (yellow arrow) transfers to a mitochondrion and then translocates along the mitochondrion with no division in the observation time period. See also Video 2. (B) Four-color time-lapse images of live GFP-Drp1-KI cell expressing mito-BFP (mitochondria, gray), mPlum-peroxisome (peroxisome, blue), ER-tagRFP (ER, red) and GFP-Drp1 in green. Yellow arrow denotes an ER-bound Drp1 puncta transferring to mitochondrion. See also Video 3. (C) Three-color time-lapse images of live GFP-Drp1-KI cell expressing mCherry-mito7 (mitochondria, red), eBFP2-peroxisome (peroxisome, blue), and Drp1 in green. Two Drp1 punctae transfer to constriction sites, followed by division. Cells treated with ionomycin (4 µM) to stimulate mitochondrial division. See also Video 4. (D) Four-color time-lapse images of live GFP-Drp1-KI cell expressing mito-BFP (mitochondria, red), mPlum-PMP20 (peroxisome, gray), ER-tagRFP (ER in blue) and GFP-Drp1 in green. Yellow arrow denotes an independent Drp1 puncta transferring to mitochondrion. Cells treated with ionomycin (4 µM) to stimulate mitochondrial division. See also Video 5. Bars, 2 µm. Time in seconds.