Complexin 1 (CPLX1)

Proteins encoded by the complexin/synaphin gene family are cytosolic proteins that function in synaptic vesicle exocytosis. These proteins bind syntaxin, part of the SNAP receptor. Complexin-1 binds to the SNAP receptor complex and disrupts it, allowing transmitter release. The highly specialized uptake and exocytosis system of synaptic vesicle traffic has been studied extensively as a model of membrane fusion. The fusion reaction begins with the assembly of a core complex consisting of the plasma membrane proteins syntaxin and SNAP25 and the synaptic vesicle protein synaptobrevin. The core complex then serves as a soluble NSF attachment protein receptor, or SNARE. Binding of SNAP to SNARE leads to ATP-dependent binding of NSF, which subsequently catalyzes disruption of the SNARE complex.