Knockdown of Mfn1/Mfn2 and Drp1/Fis1 reduces mitochondrial fusion and fission in DM cybrid, respectively. siRNA transfection was performed to knockdown target gene expression. Scramble dsRNA (scr) was used as siRNA negative control. (a) Abundance of dynamic proteins Mfn1, Mfn2, Drp1, and Fis1 was determined using Western blotting. β-Actin served as loading control. (b) Mitochondrial morphology was visualized by transfecting cox4-DsRed (red fluorescence). An enlarged segment of each image was shown by a lower right square. (c) The MicroP algorithm categorized mitochondrial morphology into six types: small globe (blue), large globe (yellow), simple tube (green), twisted tube (orange), donut (red), and branching tube (purple). N = 75–400 mitochondria from 15–30 cells and three independent experiments.