1. Interactions between complementary SNAREs may determine the specificity of vesicle targeting to an acceptor membrane. SNAREs are integral membrane proteins that, in general, appear to be inserted in the membrane through their C-terminal ends and have most of their mass exposed on the cytoplasmic surface of the membrane. Complementary SNAREs are thought to be present in both the transport vesicles (v-SNARE), which acquire them during vesicle formation in the donor membrane, and in the acceptor membranes (t-SNARE), to which the vesicles are targeted.349 SNAP proteins bound to SNAREs are capable of binding NSF in the presence of ATP. In this scheme, SNAREs are presumed to be bivalent, having one site that binds to a SNAP and another that is specific for a complementary SNARE. Vesicle docking would then involve an NSF-mediated interaction between SNAPs bound to a v-SNARE and to a t-SNARE, as well as the direct specific interaction between the SNAREs themselves. The sequence of events that follows and leads to membrane fusion is not known. A rab protein may also be involved in the targeting and/or triggering of membrane fusion, but at this time the functional relationship between rab proteins and SNAREs is obscure. Nevertheless, hydrolysis of ATP (in NSF) and GTP (in a rab protein) are likely to follow the interaction between complementary SNAREs.
Source: The Biogenesis of Membranes and Organelles, The Online Metabolic and Molecular Bases of Inherited Disease
Citation: Valle D, Beaudet AL, Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A, Gibson K, Mitchell G. The Online Metabolic and Molecular Bases of Inherited Disease; 2014 Available at: Accessed: December 23, 2017
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