AP2B1 Component of the adaptor protein complex 2 (AP-2). Adaptor protein complexes function in protein transport via transport vesicles in different membrane traffic pathways. Adaptor protein complexes are vesicle coat components and appear to be involved in cargo selection and vesicle formation. AP-2 is involved in clathrin-dependent endocytosis in which cargo proteins are incorporated into vesicles surrounded by clathrin (clathrin-coated vesicles, CCVs) which are destined for fusion with the early endosome. The clathrin lattice serves as a mechanical scaffold but is itself unable to bind directly to membrane components. Clathrin-associated adaptor protein (AP) complexes which can bind directly to both the clathrin lattice and to the lipid and protein components of membranes are considered to be the major clathrin adaptors contributing the CCV formation. AP-2 also serves as a cargo receptor to selectively sort the membrane proteins involved in receptor-mediated endocytosis. AP-2 seems to play a role in the recycling of synaptic vesicle membranes from the presynaptic surface. AP-2 recognizes Y-X-X-[FILMV] (Y-X-X-Phi) and [ED]-X-X-X-L-[LI] endocytosis signal motifs within the cytosolic tails of transmembrane cargo molecules. AP-2 may also play a role in maintaining normal post-endocytic trafficking through the ARF6-regulated, non-clathrin pathway. The AP-2 beta subunit acts via its C-terminal appendage domain as a scaffolding platform for endocytic accessory proteins; at least some clathrin-associated sorting proteins (CLASPs) are recognized by their [DE]-X(1,2)-F-X-X-[FL]-X-X-X-R motif. The AP-2 beta subunit binds to clathrin heavy chain, promoting clathrin lattice assembly; clathrin displaces at least some CLASPs from AP2B1 which probably then can be positioned for further coat assembly. Belongs to the adaptor complexes large subunit family. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.

Protein type: Vesicle

Chromosomal Location of human Ortholog: 17q12

Cellular Component: AP-2 adaptor complex; clathrin adaptor complex; clathrin-coated endocytic vesicle; clathrin-coated endocytic vesicle membrane; cytoplasmic side of plasma membrane; cytosol; endocytic vesicle membrane; endolysosome membrane; glutamatergic synapse; plasma membrane; postsynapse; presynapse

Molecular Function: clathrin adaptor activity; clathrin binding; protein binding; signal sequence binding

Biological Process: aorta development; clathrin-dependent endocytosis; coronary vasculature development; intracellular protein transport; kidney development; postsynaptic neurotransmitter receptor internalization; synaptic vesicle endocytosis; ventricular septum development; vesicle-mediated transport

Reference #: P63010 (UniProtKB)

Alt. Names/Synonyms: Adapter-related protein complex 2 beta subunit; adapter-related protein complex 2 subunit beta; adaptin, beta 2 (beta); Adaptor protein complex AP-2 subunit beta; adaptor related protein complex 2 beta 1 subunit; adaptor related protein complex 2 subunit beta 1; Adaptor-related protein complex 2 subunit beta; adaptor-related protein complex 2, beta 1 subunit; ADTB2; AP-2 complex subunit beta; AP105B; AP2-BETA; AP2B1; Beta-2-adaptin; Beta-adaptin; CLAPB1; Clathrin assembly protein complex 2 beta large chain; clathrin-associated/assembly/adaptor protein, large, beta 1; DKFZp781K0743; Plasma membrane adaptor HA2/AP2 adaptin beta subunit; testicular tissue protein Li 22

Gene Symbols: AP2B1

Molecular weight: 104,553 Da

Basal Isoelectric point: 5.22 Predict pI for various phosphorylation states

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AP2B1

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