Binding of the synaptic vesicle v-SNARE, synaptotagmin, to the plasma membrane t-SNARE, SNAP-25, can explain docked vesicles at neurotoxin-treated synapses.

Neurotransmitter release requires the specific docking of synaptic vesicles to the presynaptic plasma membrane followed by a calcium-triggered fusion event. Herein we report a previously unsuspected interaction of the synaptic vesicle protein and likely calcium sensor synaptotagmin with the plasma membrane t-SNARE SNAP-25. This interaction appears to resolve the apparent paradox that synaptic vesicles are capable of docking even when VAMP (vesicle-associated membrane protein) or syntaxin is cleaved or deleted and suggests that two species of v-SNAREs (VAMP and synaptotagmin) and two species of t-SNAREs (SNAP-25 and syntaxin) interact to functionally dock synaptic vesicles.