The BLOC-1 complex is required for normal biogenesis of lysosome-related organelles, such as platelet dense granules and melanosomes. Plays a role in intracellular vesicle trafficking. Plays a role in synaptic vesicle trafficking and in neurotransmitter release. May be required for normal dopamine homeostasis in the cerebral cortex, hippocampus, and hypothalamus. Plays a role in the regulation of cell surface exposure of DRD2. Contributes to the regulation of dopamine signaling. May play a role in actin cytoskeleton reorganization and neurite outgrowth. May modulate MAPK8 phosphorylation. Part of the biogenesis of lysosome-related organelles complex 1 (BLOC-1). The BLOC-1 complex is composed of BLOC1S1, BLOC1S2, BLOC1S3, DTNBP1, MUTED, PLDN, CNO/cappuccino and SNAPIN. Binds to DTNA and DTNB but may not be a physiological binding partner (PubMed:16980328). Interacts with RNF151 and CMYA5. Identified in a complex with the adapter-related protein complex 3 (AP-3). Interacts with TRIM32, AP3M1 and AP3B2. Identified in a complex with the biogenesis of lysosome-related organelles complex 2 (BLOC-2). Interacts with the DNA-dependent protein kinase complex DNA-PK. Detected in brain, in neurons and in neuropil. Detected in dentate gyrus and in pyramidal cells of hippocampus CA2 and CA3. Belongs to the dysbindin family. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.