Fig. 3. Effects of Munc18, complexin, and the regulatory H_abc domain of syntaxin-1a on docking and fusion.

Docking and fusion probability for DCVs to planar supported bilayers containing truncated syntaxin-1a (residues 183 to 288):SNAP-25 (A and B) or full-length syntaxin-1a (1 to 288):SNAP-25 (C and D) in the presence of 0.5 μM Munc18, 2 μM complexin-1 (cpx1), or both. Black and red bar data were obtained in the absence and presence of Ca²⁺, respectively. Summary of events and fitting results are presented in tables S9 and S10. Western blots show that Munc18 and complexin-1 were not detectable in DCV-enriched fractions prepared by centrifugation (fig. S6).