Fig. 4.

VPS35 Mutation Affects the Movement of Late Endosomes. a iPSC-derived neurons (iNeurons) stably expressing RFP-Rab7a were imaged by time-lapse fluorescence microscopy. RFP-Rab7a (red; late endosomes). Late endosomal vesicles are indicated by white arrows. b Distribution of the maximum velocities of moving RFP-Rab7a vesicles in the control and PD groups (n = 3 per line, total n = 140 moving vesicles in 14 neurons in each group). c Distribution of the mean velocities of moving RFP-Rab7a vesicles in the control and PD groups (n = 3 per line, total n = 140 moving vesicles in 14 neurons in each group). d, e Quantification of the maximum and mean velocities of vesicles (RFP-Rab7a) in iNeurons. Data are represented as mean ± SEM; ***P < 0.001; Mann–Whitney U-test in d and e. Scale bar, 10 μm in a. See also Additional file 11: Movie S7 and Additional file 12: Movie S8