Ap-2 Complex Subunit Beta (AP2B1) Antibody – Rabbit Polyclonal

The protein encoded by this gene is one of two large chain components of the assembly protein complex 2, which serves to link clathrin to receptors in coated vesicles. The encoded protein is found on the cytoplasmic face of coated vesicles in the plasma membrane. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]

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. 2 isoforms of the human protein are produced by alternative splicing.

Protein type: Vesicle

Chromosomal Location of Human Ortholog: 17q12

Cellular Component: AP-2 adaptor complex; cytosol; intracellular membrane-bound organelle; membrane; plasma membrane; trans-Golgi network

Molecular Function: clathrin binding; protein binding; protein complex binding; protein transporter activity; signal sequence binding

Biological Process: antigen processing and presentation of exogenous peptide antigen via MHC class II; axon guidance; clathrin cage assembly; ephrin receptor signaling pathway; epidermal growth factor receptor signaling pathway; intracellular protein transport; negative regulation of epidermal growth factor receptor signaling pathway; nerve growth factor receptor signaling pathway; regulation of defense response to virus by virus; synaptic transmission; viral reproduction