Complexin

Complexin

Complexin is a cytoplasmic nerve tissue protein which binds to the SNARE protein complex (SNAREpin) with a high affinity. The transport vesicle protein synaptotagmin, among others, in the presence of Ca2+, displaces complexin allowing the SNARE protein complex to bind the transport vesicle to the presynaptic membrane, although the precise mechanism remains unknown. Complexin acts both as an inhibitor and a facilitator of vesicle fusion and neurotransmitter release at the synapse. In one conformation, it clamps SNAREpin complexes, preventing vesicle fusion, while in a different conformation it releases the SNAREpins, allowing synaptotagmin to trigger fusion. [1] This makes complexin a critical gatekeeper in the synaptic vesicle fusion process.

Genes

See also