(A, C, E, G and I) Example micrographs showing endocytic pits and ferritin-containing endocytic structures at the indicated time points in Dyn3 KO (A), Dyn1,3 DKO (C), Dyn1,3 DKO, Dyn1xA overexpression (OEx) (E), Dyn1,3 DKO, Dyn1xA S774/778A OEx (G), Dyn1,3 DKO, Dyn1xA S774/778D OEx (I). Black arrowheads, endocytic invaginations; black arrows, LEVs or endosomes; white arrowheads, synaptic vesicles. Note that the endocytic defect can be rescued with Dyn1xA S774/778A but not with Dyn1xA S774/778D. Scale bar: 100 nm. PSD, post-synaptic density.
(B, D, F, H and J) Plots showing the increase in the number of each ferritin-positive endocytic structure per synaptic profile after a single stimulus in neurons with the indicated genotypes. (J). The mean and SEM are shown in each graph.
(K) Number of endocytic invaginations at 1s after the stimulations. The numbers are re-plotted as a bar graph from the 1 s time point in (B, D, F, H, and J).
(L) Number of LEVs and endosomes at 1s after stimulation. The numbers of LEVs and endosomes are summed from the data presented in (B, D, F, H, and J) and averaged.
(M and N) Plots showing the width (M) and depth (N) of endocytic pits at the 1s time point.
*p < 0.05, **p < 0.0001. See Data S1 for the n values, statistical test, and detailed numbers.