Tomosyn plays a regulatory role in calcium-dependent exocytosis and neurotransmitter release by inhibiting the assembly of trans-SNARE complexes between transport vesicles and the plasma membrane, via the displacement of munc18 from syntaxin-1. There are three splice variants of tomosyn designated m-tomosyn, b-tomosyn and s-tomosyn. Although b-tomosyn is ubiquitously expressed, s-tomosyn and m-tomosyn are expressed primarily in brain.
Cell Membrane and Cytoplasmic.
Note: Cytoplasmic, and associated with vesicular membranes and the plasma membrane. Detected at synapses and on synaptic vesicles