Figure 3

KIF5B drives peripheral mitochondrial network formation in three steps. (A) KIF5B^−/− NRK cells that stably express Mito-YFP and TET-ON-KIF5B were treated with 0.5 μg/ml tetracycline, and then observed by spinning-disk microscopy. Scale bar, 20 μm. Red dashed boxes are enlarged in the lower panels. Red dashed lines in the lower panels indicate the boundary of the mitochondrial network before tubulation, and white arrows indicate dynamic tubules. Scale bar in enlarged panels, 10 μm. (B) KIF5B^−/− NRK cells that stably express Mito-YFP and TET-ON-KIF5B were treated with 0.5 μg/ml tetracycline for 1 h, and then observed by spinning-disk microscopy. Scale bar, 2 μm. White arrows indicate a dynamic tubule. (C) Quantification of the frequency of outward tubulation from the mitochondrial boundary. n = 90 cells from three independent experiments. Error bars indicate SD. (D) KIF5B^−/− NRK cells that stably express Mito-YFP and TET-ON-KIF5B were treated with 0.5 μg/ml tetracycline for 1 h. Cells were observed by spinning-disk microscopy. Scale bar, 2 μm. White arrows indicate a fusion event. (E) KIF5B^−/− NRK cells that stably express Mito-YFP and TET-ON-KIF5B were treated with 0.5 μg/ml tetracycline for 2 h. Cells were observed by spinning-disk microscopy. Scale bar, 2 μm. White arrows indicate dynamic tubules.