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 (PubMed:17182842). 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 negatively regulate aerobic respiration through mitochondrial protein lysine-acetylation. May counteract the action of the deacetylase SIRT3 by acetylating and regulating proteins of the mitochondrial respiratory chain including ATP5F1A and NDUFA9. 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 (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 ATP5F1A and NDUFA9; involved in their acetylation on lysine residues (PubMed:22309213). Interacts with KXD1 (By similarity). May be produced by alternative initiation at Met-27 of isoform 1. A polymorphism at position 9 leads to the creation of a stop codon. Isoform 2 is the only form that exists in orthologs (except primates). Belongs to the BLOC1S1 family. Truncated N-terminus.