FIGURE 5.

Slow vGlut1 internalization slows internalization of other SV cargos via the PP2 domain. A, graphic illustrates the experimental design to examine the influence of mutant vG on other cargo internalization. B, representative endocytosis kinetics (thick traces) with their corresponding single exponential fits (smooth and thin traces) of various cargo proteins (black) and those from neurons co-expressed with vGAA (red) and vGAAΔPP2 (blue). C, summary of the effect of vGAA and vGAAΔPP2 on SV2, Syphy, VAMP2, and Syt1 endocytosis kinetics. Significant difference was only found for SV2 (9.6 ± 0.8 s, n = 7) when compared with SV2 co-expressing vGAA (16.8 ± 2.4 s, n = 8, p = 0.02, two-tailed Student's t test) and Syphy (10.2 ± 0.9 s, n = 7) when compared with Syphy co-expressing vGAA (14.1 ± 1.3 s, n = 7, p = 0.03, two-tailed Student's t test). D, endocytic time constants of Syphy-pHluorin when expressed alone, with HA-vGAA on the WT vG background, or with HA-vGAA (resvGAA) on the vG KD background. No difference was observed between the WT vG background and the KD background (p = 0.87, Wilcoxon rank sum test). Error bars indicate S.E.