AP2A1 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 alpha subunit binds polyphosphoinositide-containing lipids, positioning AP-2 on the membrane. The AP-2 alpha subunit acts via its C-terminal appendage domain as a scaffolding platform for endocytic accessory proteins. The AP-2 alpha and AP-2 sigma subunits are thought to contribute to the recognition of the [ED]-X-X-X-L-[LI] motif. Belongs to the adaptor complexes large subunit family. Isoform A expressed in forebrain, skeletal muscle, spinal cord, cerebellum, salivary gland, heart and colon. Isoform B is widely expressed in tissues and also in breast cancer and in prostate carcinoma cells. 2 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: Adaptor/scaffold; Vesicle
Chromosomal Location of Human Ortholog: 19q13.33
Cellular Component:  AP-2 adaptor complex; apical plasma membrane; basolateral plasma membrane; clathrin coat of trans-Golgi network vesicle; clathrin-coated endocytic vesicle; clathrin-coated endocytic vesicle membrane; cytosol; endocytic vesicle membrane; endolysosome membrane; filopodium tip; plasma membrane
Molecular Function:  low-density lipoprotein particle receptor binding; protein binding; protein C-terminus binding; protein kinase binding; protein-containing complex binding
Biological Process:  antigen processing and presentation of exogenous peptide antigen via MHC class II; clathrin-dependent endocytosis; endocytosis; ephrin receptor signaling pathway; Golgi to endosome transport; intracellular protein transport; low-density lipoprotein particle clearance; low-density lipoprotein particle receptor catabolic process; membrane organization; negative regulation of hyaluronan biosynthetic process; positive regulation of neuron projection development; positive regulation of receptor-mediated endocytosis; regulation of defense response to virus by virus; Wnt signaling pathway, planar cell polarity pathway
Reference #:  O95782 (UniProtKB)
Alt. Names/Synonyms: 100 kDa coated vesicle protein A; Adapter-related protein complex 2 alpha-1 subunit; adaptin, alpha A; Adaptor protein complex AP-2 subunit alpha-1; adaptor-related protein complex 2, alpha 1 subunit; ADTAA; Alpha-adaptin A; Alpha1-adaptin; AP-2 complex subunit alpha-1; AP2-ALPHA; AP2A1; CLAPA1; Clathrin assembly protein complex 2 alpha-A large chain; clathrin-associated/assembly/adaptor protein, large, alpha 1; Plasma membrane adaptor HA2/AP2 adaptin alpha A subunit
Gene Symbols: AP2A1
Molecular weight: 107,546 Da
Basal Isoelectric point: 6.63  Predict pI for various phosphorylation states
CST Pathways:  Notch Signaling
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Protein Structure Not Found.

Cross-references to other databases:  STRING  |  cBioPortal  |  Wikipedia  |  Reactome  |  neXtProt  |  Protein Atlas  |  BioGPS  |  Pfam  |  Phospho.ELM  |  NetworKIN  |  GeneCards  |  UniProtKB  |  Entrez-Gene  |  GenPept  |  Ensembl Gene  |  Ensembl Protein