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 mouse Ortholog: 7|7 B3
Cellular Component:  AP-2 adaptor complex; apical plasma membrane; basolateral plasma membrane; clathrin adaptor complex; clathrin-coated pit; clathrin-coated vesicle; cytoplasmic side of plasma membrane; filopodium tip; membrane; membrane coat; plasma membrane; protein-containing complex; secretory granule
Molecular Function:  cargo adaptor activity; clathrin adaptor activity; low-density lipoprotein particle receptor binding; protein binding; protein C-terminus binding; protein kinase binding; protein-containing complex binding
Biological Process:  clathrin-dependent endocytosis; endocytosis; intracellular protein transport; negative regulation of hyaluronan biosynthetic process; positive regulation of neuron projection development; positive regulation of receptor-mediated endocytosis; postsynaptic neurotransmitter receptor internalization; protein transport; receptor-mediated endocytosis; vesicle-mediated transport
Reference #:  P17426 (UniProtKB)
Alt. Names/Synonyms: 100 kDa coated vesicle protein A; Adapter-related protein complex 2 alpha-1 subunit; adapter-related protein complex 2 subunit alpha-1; Adaptor protein complex AP-2 subunit alpha-1; adaptor protein complex AP-2, alpha 1 subunit; Adaptor-related protein complex 2 subunit alpha-1; adaptor-related protein complex 2, alpha 1 subunit; adaptor-related protein complex AP-2, alpha 1 subunit; Adtaa; Alpha-adaptin A; Alpha1-adaptin; AP-2 complex subunit alpha-1; Ap2a1; Clapa1; Clathrin assembly protein complex 2 alpha-A large chain; Plasma membrane adaptor HA2/AP2 adaptin alpha A subunit
Gene Symbols: Ap2a1
Molecular weight: 107,664 Da
Basal Isoelectric point: 6.63  Predict pI for various phosphorylation states
CST Pathways:  Notch Signaling
Select Structure to View Below


Protein Structure Not Found.

Cross-references to other databases:  AlphaFold  |  STRING  |  Reactome  |  BioGPS  |  Pfam  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  Ensembl Gene