Synaptosomal-associated Protein 23 (SNAP23), also known as Syndet, is a member of the SNAP25 family of t-SNARE proteins that play a role in vesicle exocytosis. Human SNAP23 is 211 amino acids (aa) in length and has a predicted molecular weight of approximately 23 kDa. It contains two t-SNARE coiled-coil homology domains at aa 14-76 and 146-208. There is one splice variant, termed SNAP23B, that contains a deletion of aa 90-142. The canonical sequence of human SNAP23 shares 87% aa sequence identity with the mouse and rat orthologs. It has been suggested the SNAP23 may function as both a v-SNARE and a t-SNARE. As a v-SNARE, SNAP23 can interact with Syntaxin-6 at the cell membrane. As a t-SNARE, it acts in conjunction with Syntaxin-4 to bind with VAMP-2 and VAMP-8 on the vesicle membrane. In either case, this approximates the two membranes, which subsequently fuse to create a pore. SNAP23 is expressed in multiple cell types including adipocytes, mast cells, platelets, neutrophils, and is critical for vesicle exocytosis in these non-neuronal cells. In the nervous system, high SNAP23 expression has been detected in the postsynaptic density of dendritic spines. As a consequence, it has been suggested that in the central nervous system, SNAP23 is not involved in the exocytosis of neurotransmitters, but may instead play a role in the trafficking of postsynaptic glutamate receptors.