AP3B1
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.
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.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Phosphorylated on serine residues.
Pyrophosphorylation by 5-diphosphoinositol pentakisphosphate (5-IP7) impairs interaction with KIF3A (PubMed:19934039). Serine pyrophosphorylation is achieved by Mg(2+)-dependent, but enzyme independent transfer of a beta-phosphate from a inositol pyrophosphate to a pre-phosphorylated serine residue (PubMed:19934039).
Sequence Similarities
Belongs to the adaptor complexes large subunit family.
Tissue Specificity
Ubiquitously expressed.
Cellular localization
- Cytoplasmic vesicle
- Clathrin-coated vesicle membrane
- Peripheral membrane protein
- Cytoplasmic side
- Golgi apparatus
- Component of the coat surrounding the cytoplasmic face of coated vesicles located at the Golgi complex.
Alternative names
ADTB3A, AP3B1, AP-3 complex subunit beta-1, Adaptor protein complex AP-3 subunit beta-1, Adaptor-related protein complex 3 subunit beta-1, Beta-3A-adaptin, Clathrin assembly protein complex 3 beta-1 large chain