Fig. 6: Endophilin BAR-domains are not sufficient to mediate chromaffin cell exocytosis.
From: Endophilin-A coordinates priming and fusion of neurosecretory vesicles via intersectin
a Schematic depicting the domain structure of endophilin 2 and two mutants lacking the SH3 domain expressed in the subsequent experiments. b Exocytosis induced by calcium uncaging in endophilin TKO chromaffin cells (red traces) compared to TKO cells expressing either endophilin 1 BAR domain (yellow traces), endophilin 2-BAR domain (green traces) or full-length endophilin 2 WT protein (gray traces). Panel arranged as in Fig. 1i, top: intracellular calcium level increase induced by flash photolysis at 0.5 s (at arrow). The inset shows the pre-flash calcium levels. Middle: averaged traces of membrane capacitance upon Ca2+-induced exocytosis. Bottom: mean amperometric current (left axis) and cumulative charge (right axis). c–e Quantification of changes in capacitance revealed a further reduction in different phases of release (burst and sustained) in TKO cells expressing endophilin 1-BAR or endophilin 2-BAR domain. Gray line indicates the mean of TKO cells expressing endophilin 2 full-length protein and the shaded area indicates the SEM. b–e N = 3, 3 mice/condition, cells TKO (16), TKO + endophilin1 BAR (17) and TKO + endophilin 2-BAR (17). Error bars denote SEM. N = number of independent replicates. One-way ANOVA with Tukey’s multiple comparison test, *p < 0.05, **p < 0.01.
