Regulation of Exocytosis by Complexin

Abstract

Complexin (Cpx), which is expressed mainly in the nervous system, binds efficiently to the SNARE complex that is composed of either Syntaxin 1 or Syntaxin 3. Both Syntaxin 1 and Syntaxin 3 are involved in mediating synchronous neurotransmitter release in the nervous system. Cpx stabilizes the SNARE complex upon binding, and potentiates the efficacy of synchronous exocytotic process. Cpx is consisted of N-terminal, accessory α-helix, central α-helix, and C-terminal domains. Each domain of Cpx has a distinct function that is differentially involved in the regulation of priming, clamping, and activating in the exocytotic process. These functions of Cpx domains coordinately potentiate the efficacy of synchronous exocytotic process.