SNAPIN

The protein encoded by this gene is a coiled-coil-forming protein that associates with the SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) complex of proteins and the BLOC-1 (biogenesis of lysosome-related organelles) complex. Biochemical studies have identified additional binding partners. As part of the SNARE complex, it is required for vesicle docking and fusion and regulates neurotransmitter release. The BLOC-1 complex is required for the biogenesis of specialized organelles such as melanosomes and platelet dense granules. Mutations in gene products that form the BLOC-1 complex have been identified in mouse strains that are models of Hermansky-Pudlak syndrome. Alternative splicing results in multiple transcript variants.

SNAP Associated Protein

Component of the BLOC-1 complex, a complex that is required for normal biogenesis of lysosome-related organelles (LRO), such as platelet dense granules and melanosomes. In concert with the AP-3 complex, the BLOC-1 complex is required to target membrane protein cargos into vesicles assembled at cell bodies for delivery into neurites and nerve terminals. The BLOC-1 complex, in association with SNARE proteins, is also proposed to be involved in neurite extension. Plays a role in intracellular vesicle trafficking and synaptic vesicle recycling. May modulate a step between vesicle priming, fusion and calcium-dependent neurotransmitter release through its ability to potentiate the interaction of synaptotagmin with the SNAREs and the plasma-membrane-associated protein SNAP25. Its phosphorylation state influences exocytotic protein interactions and may regulate synaptic vesicle exocytosis. May also have a role in the mechanisms of SNARE-mediated membrane fusion in non-neuronal cells (PubMed:17182842, PubMed:18167355).
As part of the BORC complex may play a role in lysosomes movement and localization at the cell periphery. Associated with the cytosolic face of lysosomes, the BORC complex may recruit ARL8B and couple lysosomes to microtubule plus-end-directed kinesin motor (PubMed:25898167).

Biological Process anterograde axonal transportISS:UniProtKB
Biological Process anterograde synaptic vesicle transportISS:UniProtKB
Biological Process autophagosome maturationIEA:Ensembl
Biological Process endosome to lysosome transportManual Assertion Based On ExperimentIGI:MGI
Biological Process intracellular protein transportManual Assertion Based On ExperimentTAS:ProtInc
Biological Process late endosome to lysosome transportIEA:Ensembl
Biological Process lysosomal lumen acidificationIEA:Ensembl
Biological Process lysosome localizationManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process lysosome organizationManual Assertion Based On ExperimentIBA:GO_Central
Biological Process melanosome organization1 PublicationNAS:UniProtKB
Biological Process negative regulation of neuron projection developmentIEA:Ensembl
Biological Process neuron cellular homeostasisIEA:Ensembl
Biological Process neuron projection developmentISS:UniProtKB
Biological Process neurotransmitter secretionManual Assertion Based On ExperimentTAS:ProtInc
Biological Process organelle transport along microtubule1 PublicationIC:ComplexPortal
Biological Process positive regulation of late endosome to lysosome transportManual Assertion Based On ExperimentTAS:ParkinsonsUK-UCL
Biological Process protein maturationIEA:Ensembl
Biological Process protein-containing complex localizationIEA:Ensembl
Biological Process regulation of endosome size1 PublicationIC:ComplexPortal
Biological Process regulation of lysosome size1 PublicationIC:ComplexPortal
Biological Process regulation of protein bindingManual Assertion Based On ExperimentIMP:ParkinsonsUK-UCL
Biological Process regulation of synaptic vesicle exocytosisManual Assertion Based On ExperimentIBA:GO_Central
Biological Process retrograde axonal transportIEA:Ensembl
Biological Process synaptic vesicle exocytosisManual Assertion Based On ExperimentIDA:MGI
Biological Process synaptic vesicle fusion to presynaptic active zone membraneIEA:Ensembl
Biological Process synaptic vesicle maturationIEA:Ensembl
Biological Process synaptic vesicle transportManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process terminal button organizationIEA:Ensembl

Membrane
Cytoplasm, cytosol
Cytoplasm, perinuclear region
Golgi apparatus membrane
Lysosome membrane
Cytoplasmic vesicle, secretory vesicle, synaptic vesicle membrane
Colocalizes with NANOS1 and PUM2 in the perinuclear region of germ cells.

Phosphorylated by CSNK1D/CK1 (By similarity).
Phosphorylated by PKD, phosphorylation controls SNAPIN protein stability.