Syntaxin: A Synaptic Protein Implicated in Docking of Synaptic Vesicles at Presynaptic Active Zones

TLDR

Synaptic vesicles store neurotransmitters and release them via calcium‑regulated exocytosis, a process that requires precise localization of vesicles and calcium channels to presynaptic active zones, where neuron‑specific p35 proteins (syntaxins) are concentrated on the plasma membrane. The p35 proteins may function in docking synaptic vesicles near calcium channels at presynaptic active zones. Two 35‑kDa syntaxins that bind synaptotagmin were found, and an anti‑p35 antibody co‑precipitated N‑type calcium channels, supporting a role for p35 in linking vesicles to calcium channels.

Abstract

Synaptic vesicles store neurotransmitters that are released during calcium-regulated exocytosis. The specificity of neurotransmitter release requires the localization of both synaptic vesicles and calcium channels to the presynaptic active zone. Two 35-kilodalton proteins (p35 or syntaxins) were identified that interact with the synaptic vesicle protein p65 (synaptotagmin). The p35 proteins are expressed only in the nervous system, are 84 percent identical, include carboxyl-terminal membrane anchors, and are concentrated on the plasma membrane at synaptic sites. An antibody to p35 immunoprecipitated solubilized N-type calcium channels. The p35 proteins may function in docking synaptic vesicles near calcium channels at presynaptic active zones.