FIG. 4.

Inhibition of mitochondrial fission induces the large-scale fluctuation of the inner membrane potential. The mitochondrial inner membrane potential was evaluated with TMRE fluorescence. A–D: The TMRE fluorescence intensity showed no overall difference in control and DLP1-K38A-expressing cells. C: Cells expressing DLP1-K38A appeared to have larger cell-to-cell variations, however. D: FCCP treatment dissipated the TMRE fluorescence. Error bars are SEM. E–G: Time-lapse imaging shows TMRE fluorescence in hepatocytes expressing DLP1-K38A. E: Time sequence images show repeated loss and recovery of TMRE fluorescence, and the arrowheads denote depolarized mitochondria at given time points, which regain the membrane potential afterward. F: Quantification of TMRE fluorescence intensity (FI) in five different oscillating mitochondria shows a rapid decrease and slower restoration of the membrane potential. The frequency and interval of the oscillation are random. G: Fluorescence quantification shows that a decrease (gray line) of TMRE fluorescence during the oscillation is accompanied by hyperpolarization (black line) of remaining adjacent mitochondria.