Fig 1: Mitochondria trafficking analyses in human iPSC-derived axons.a Mitochondrial movement in representative axons transfected with mito-dsRed. The first frame of each live-imaging series is shown above a kymograph generated from the movie. The x-axis is mitochondrial position and the y-axis corresponds to time (moving from top to bottom). Scale bars: 10 µm. b–e From kymographs as in (a), Percent of Time each mitochondrion is in motion (b), Average Velocity (c), Stop Frequency (d), or Turn Back Frequency (e) is quantified. Percent of Time in Motion is calculated by the number of instantaneous velocities that are not zero divided by the total number of instantaneous velocities (including both zero and non-zero) for a mitochondrion; Average Velocity is defined as the average velocity of all instantaneous velocities that are not zero for a mitochondrion; Stop Frequency is defined as the frequency per mitochondrion that the instantaneous velocity changes to zero; Turn Back Frequency is defined as the frequency per mitochondrion that the direction of instantaneous velocity reverses. Data are shown as mean ± SEM. One-way ANOVA with Tukey’s multiple comparisons test (95% CI). *p < 0.05, **p < 0.01, ***p < 0.001. (exact p values and sample size: b anterograde, p < 0.0001 (MTX1); p = 0.0294 (MTX2); p = 0.0003 (Trak1); p = 0.0005 (Trak2). retrograde, p < 0.0001 (MTX1); p = 0.0003 (MTX2); p < 0.0001 (Trak1); p < 0.0001 (Trak2). c anterograde, p = 0.0950 (MTX1); p > 0.9999 (MTX2); p = 0.0231 (Trak1); p = 0.0947 (Trak2). retrograde, p = 0.0474 (MTX1); p = 0.3399 (MTX2); p = 0.9733 (Trak1); p = 0.9254 (Trak2). d p < 0.0001 (MTX1); p < 0.0001 (MTX2); p < 0.0001 (Trak1); p < 0.0001 (Trak2). e p = 0.0015 (MTX1); p = 0.0033 (MTX2); p = 0.0425 (Trak1); p < 0.0001 (Trak2). n = 113 (control RNAi), 138 (MTX1 RNAi), 125 (MTX2 RNAi), 90 (Trak1 RNAi), 95 (Trak2 RNAi) mitochondria (b, d, e); 44 (control RNAi), 15 (MTX1 RNAi), 21 (MTX2 RNAi), 11 (Trak1 RNAi), 10 (Trak2 RNAi) (c, anterograde); and 41 (control RNAi), 17 (MTX1 RNAi), 16 (MTX2 RNAi), 11 (Trak1 RNAi), 3 (Trak2 RNAi) (c, retrograde) from 12 (control RNAi), 16 (MTX1 RNAi), 14 (MTX2 RNAi), 10 (Trak1 RNAi), 11 (Trak2 RNAi) axons from four independent transfections). Source data are provided as a Source Data file.