(A) FIS1 and DRP1 knockdown reduced maximal respiratory chain capacity in FIS1 RNAi and DRP1‐DN compared with their control (n=4 in each group; glucose=11 mM). Inhibition of autophagy by 3‐MA in INS1 cells (2 mM, 5 days, n=4) and C2C12 cells (1 mM, 5 days, n=4) showed significant decrease in respiratory capacity. ATG5‐deficient MEF cells (n=4) had significantly decreased respiratory capacity compared with control MEF cells. Maximal respiration was tested using 5 μM FCCP or 100 μM DNP (*P0.001, **P0.04). 