AP3B1

This gene encodes a protein that may play a role in organelle biogenesis associated with melanosomes, platelet dense granules, and lysosomes. The encoded protein is part of the heterotetrameric AP-3 protein complex which interacts with the scaffolding protein clathrin. Mutations in this gene are associated with Hermansky-Pudlak syndrome type 2. [provided by RefSeq]

Full Name

adaptor-related protein complex 3, beta 1 subunit

Function

Subunit of non-clathrin- and clathrin-associated adaptor protein complex 3 (AP-3) that plays a role in protein sorting in the late-Golgi/trans-Golgi network (TGN) and/or endosomes. The AP complexes mediate both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules. AP-3 appears to be involved in the sorting of a subset of transmembrane proteins targeted to lysosomes and lysosome-related organelles. In concert with the BLOC-1 complex, AP-3 is required to target cargos into vesicles assembled at cell bodies for delivery into neurites and nerve terminals.

Biological Process

Anterograde axonal transport Source: UniProtKB
Anterograde synaptic vesicle transport Source: UniProtKB
Antigen processing and presentation, exogenous lipid antigen via MHC class Ib Source: Ensembl
Blood coagulation Source: Ensembl
Cell morphogenesis Source: Ensembl
Cellular protein modification process Source: Ensembl
Cellular zinc ion homeostasis Source: Ensembl
Establishment of protein localization to mitochondrial membrane involved in mitochondrial fission Source: Ensembl
Granulocyte differentiation Source: Ensembl
Hematopoietic progenitor cell differentiation Source: Ensembl
Homeostasis of number of cells Source: Ensembl
Inflammatory response Source: Ensembl
Intracellular protein transport Source: ProtInc
Lung morphogenesis Source: Ensembl
Lysosome organization Source: Ensembl
Melanosome organization Source: UniProtKB
mRNA transcription by RNA polymerase II Source: Ensembl
Platelet dense granule organization Source: Ensembl
Positive regulation of NK T cell differentiation Source: Ensembl
Positive regulation of transcription by RNA polymerase II Source: Ensembl
Protein localization to cell surface Source: Ensembl
Protein targeting to lysosome Source: Ensembl
Regulation of catalytic activity Source: Ensembl
Respiratory system process Source: Ensembl
Single fertilization Source: Ensembl
Skin epidermis development Source: Ensembl
Spermatogenesis Source: Ensembl
Synaptic vesicle budding from endosome Source: Ensembl
Toll-like receptor signaling pathway Source: Ensembl
Vesicle-mediated transport Source: GO_Central

Cellular Location

Golgi apparatus; Clathrin-coated vesicle membrane. Component of the coat surrounding the cytoplasmic face of coated vesicles located at the Golgi complex.

Involvement in disease

Hermansky-Pudlak syndrome 2 (HPS2): A form of Hermansky-Pudlak syndrome, a genetically heterogeneous autosomal recessive disorder characterized by oculocutaneous albinism, bleeding due to platelet storage pool deficiency, and lysosomal storage defects. This syndrome results from defects of diverse cytoplasmic organelles including melanosomes, platelet dense granules and lysosomes. Ceroid storage in the lungs is associated with pulmonary fibrosis, a common cause of premature death in individuals with HPS. HPS2 differs from the other forms of HPS in that it includes immunodeficiency in its phenotype and patients with HPS2 have an increased susceptibility to infections.

PTM

Phosphorylated on serine residues.
Pyrophosphorylation by 5-diphosphoinositol pentakisphosphate (5-IP7) impairs interaction with KIF3A (PubMed:19934039). Serine pyrophosphorylation is achieved by Mg2+-dependent, but enzyme independent transfer of a beta-phosphate from a inositol pyrophosphate to a pre-phosphorylated serine residue (PubMed:19934039).