Figure 7.
Cl-/H+ exchangers regulate exocytosis of LDCVs in chromaffin cells. A, Averaged [Ca2+]i (top) and corresponding capacitance responses to flash stimulation from WT chromaffin cells expressing scrambled shRNA (WT+Scr, black trace) or shRNA against Clcn5 (knock down, WT+kdClC-5, orange trace) or from Clcn3−/− cells expressing scrambled shRNA (Clcn3−/−+Scr, red trace) or shRNA against Clcn5 (DMut; Clcn3−/−+kdClC-5, blue trace) or the different rescue conditions; ClC-3b or ClC-3c (DMut+ClC-3b, brown trace, and DMut+ClC-3c, gray trace). B, Changes of the exocytotic burst in response to flash stimulation from virally transduced WT or Clcn3−/− chromaffin cells expressing different constructs (WT+Scr, n = 14, black circles, WT+kdClC-5, n = 14, orange circles; Clcn3−/−+Scr, n = 23, red circles; DMut, n = 16, blue circles; DMut+ClC-3b, n = 19, brown circles; DMut+ClC-3c, n = 10, gray circles). C, D, Knock down of ClC-5 in Clcn3−/− cells (DMut, blue circles) selectively reduce the size of the fast component of vesicle exocytosis (RRP; C), leaving the slow component (SRP) almost unaffected (D). Rescue experiments illustrate the ability of Cl−/H+ exchangers in restoring exocytosis of LDCVs in Dmut conditions. WT+Scr, n = 14, black circles; WT+kdClC-5, n = 14, orange circles; Clcn3−/−+Scr, n = 23, red circles; DMut, n = 16, blue circles; DMut+ClC-3b, n = 19; DMut+ClC-3c, n = 10, gray circles. ***p < 0.001, **p < 0.01. ns, Not significant. Groups of data were statistically analyzed by comparing them to WT+Scr or DMut using one-way ANOVA (Tukey's HSD post hoc test). Data were collected from four to five independent cultures per condition and are represented as mean ± SEM. n denotes the number of analyzed cells.