[5][6][7] SNAPAP is a component of the SNARE complex of proteins that is required for synaptic vesicle docking and fusion.

[5] SNAPAP is also a component of the ubiquitously expressed BLOC1 multisubunit protein complex.

BLOC1 is required for normal biogenesis of specialized organelles of the endosomal-lysosomal system, such as melanosomes and platelet dense granules.

[9] Specifically, the degree to which snapin is necessary for proper synaptic release varies across species.

The functions of snapin have been reported to be independent of synaptotagmin, and works through the SNAP-25 pathway to stabilize, prime, and dock vesicles.