VSNARE

Vesicle SNAREs, or vSNAREs, are a subset of SNARE proteins located on transport vesicles that mediate membrane fusion by forming a SNARE complex with target-SNAREs (t-SNAREs) on the destination membrane. They function together with t-SNAREs to drive vesicle docking and fusion, enabling regulated and constitutive trafficking within cells. The interaction typically forms a four-helix SNARE bundle whose zippering energy brings the vesicle and target membranes into close proximity, promoting fusion. After fusion, the SNARE complex is disassembled by the ATPase NSF in cooperation with α-SNAP to recycle SNARE components for new rounds of trafficking.

In neurons, the archetypal vSNARE is synaptobrevin (also called VAMP). It pairs with syntaxin-1 and SNAP-25 on the plasma membrane to drive neurotransmitter release. Other vSNAREs exist in various cellular pathways, including VAMP3 (cellubrevin), which participates in recycling endosome trafficking, and VAMP7 and VAMP8, which are implicated in late endosome/lysosome pathways and certain secretory routes. In yeast and other organisms, vesicle-associated SNAREs such as Snc1/2 perform similar exocytic roles.

Regulation involves auxiliary proteins that modulate SNARE assembly and operation, including SM proteins (e.g., Munc18), complexins, and synaptotagmin as a calcium sensor in neurons. The coordinated action of vSNAREs and tSNAREs across cell types underlies diverse processes like neurotransmission, hormone secretion, and general vesicular trafficking. Defects in vSNARE function or regulation can impact secretory efficiency and cellular homeostasis.