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 (PubMed:15102850, PubMed:17182842). 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 (By similarity). 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). May play a role in cell proliferation (PubMed:15381421). Component of the biogenesis of lysosome-related organelles complex 1 (BLOC-1) composed of BLOC1S1, BLOC1S2, BLOC1S3, BLOC1S4, BLOC1S5, BLOC1S6, DTNBP1/BLOC1S7 and SNAPIN/BLOC1S8. Octamer composed of one copy each BLOC1S1, BLOC1S2, BLOC1S3, BLOC1S4, BLOC1S5, BLOC1S6, DTNBP1/BLOC1S7 and SNAPIN/BLOC1S8. Interacts directly with BLOC1S1, BLOC1S3, BLOC1S4, BLOC1S5 and SNAPIN (PubMed:15102850, PubMed:22203680). The BLOC-1 complex associates with the AP-3 protein complex and membrane protein cargos (By similarity). Component of the BLOC-one-related complex (BORC) which is composed of BLOC1S1, BLOC1S2, BORCS5, BORCS6, BORCS7, BORCS8, KXD1 and SNAPIN (PubMed:25898167). Interacts with gamma-tubulin (PubMed:15381421). Interacts with IFT57 (By similarity). Localizes to the centrosomes in a microtubule-dependent manner. Isoform 1 and isoform 2 are widely expressed. Expressed in various malignant tumor tissues (at protein level). Belongs to the BLOC1S2 family. Truncated N-terminus.