Adaptor protein complex AP-3 subunit beta-1 (AP3B1)

Adaptor protein complex AP-3 subunit beta-1 (AP3B1) is the β3A subunit of the heterotetrameric AP-3 protein complex, which mediates vesicle formation and protein sorting primarily from the trans-Golgi network and endosomes to lysosome-related organelles such as melanosomes, lysosomes, and platelet dense granules[1][2][3][5]. AP3B1 is essential for the proper biogenesis of these organelles and participates in trafficking pathways that are critical for pigmentation, hemostasis, and immune cell function. Loss-of-function mutations cause Hermansky–Pudlak syndrome type 2 (HPS2), a disorder featuring oculocutaneous albinism, platelet storage pool deficiency (bleeding tendency), susceptibility to infections (immunodeficiency), and increased risk of pulmonary fibrosis[1][2][3][4]. AP3B1 interacts with clathrin and helps to recognize cargo proteins destined for transport, notably playing a partially redundant role with AP-1 in trafficking proteins (such as tyrosinase) to melanosomes[5]. While not a classic therapeutic target such as a receptor or enzyme, AP3B1 is of major interest in rare genetic disease, organelle biology, and protein trafficking research contexts.

Other names

AP-3 complex subunit beta-1ADTB3ADTB3AHPSHPS2PEadaptor related protein complex 3 beta 1 subunitadaptor related protein complex 3 subunit beta 1beta-3Abeta-3A-adaptinclathrin assembly protein complex 3 beta-1 large chain