Figure 3.

Analysis of the minimal truncation in SNAP-25 C terminus that sustains normal secretory activity in chromaffin cells. After averaging cumulative event responses as indicated in Fig. 2, the rate of release during the initial 10 s (INITIAL RELEASE) and extent of secretion during 1 min of stimulation (TOTAL RELEASE) was measured for control nontransfected and cells expressing the full length and deletions of SNAP-25 constructs. The structure of each construct, regarding its C terminus, is shown at the left of the figure. Data are means ± SEM from experiments performed in a number (n) of cells.