Accessory protein for SNARE

Specific function of Accessary protein



It is expressed in the brain. It is important for ultrafast exocytosis and facilitates spontaneous exocytosis of NTs. In addition, It can inhibits liposome or cell-cell fusion by clamping full zippering of the trans-SNARE complex.

[28] [97] - [99]


It is necessary for ultrafast exocytosis of NTs. Munc13 removes the Munc18 capping from syntaxin, allow only one SNAP-25 molecule to bind syntaxin, whereby it prevents misfolding to the 2:1 complex.

[28] [100] - [102]


It is identified as a SNAP25-binding protein and is expressed in both neuronal and non-neuronal cells. Snapin stabilizes the coupling between synaptotagmin1 and the SNARE complex during Ca2+ -triggered ultrafast exocytosis at central nerve terminals.

[103] [104]


It is identified as a syntaxin-binding protein in rat brain cytosol. Tomosyn is a negative regulator of exocytosis because it’s over expression causes a significant reduction in exocytosis and its deletion causes enhanced neurotransmitter release through increased synaptic vesicle priming.

[105] [106]


CAPS was originally isolated from brain cytosol as a factor required for Ca2+-triggered LDCV exocytosis. CAPS binds independently to each of the three SNARE proteins and markedly accelerates SNARE-dependent liposome fusion in vitro by promoting transSNARE complex assembly.



It is a binding partner for Rab3, a highly abundant protein in synaptic vesicles. RIM facilitate SNARE assembly by reversing autoinhibitory homodimerization of Munc13.



CAST directly or indirectly binds CAZ proteins to form a large molecular complex at the active zone. CAST also binds to RIM1 and, indirectly, to Munc13-1 to form a ternary complex. Deletion of CAST selectively affects the exocytosis of inhibitory synapses by reducing the size of the RRP.