Ap-2 Complex Subunit Sigma (AP2S1) Antibody – Rabbit Polyclonal

One of two major clathrin-associated adaptor complexes, AP-2, is a heterotetramer which is associated with the plasma membrane. This complex is composed of two large chains, a medium chain, and a small chain. This gene encodes the small chain of this complex. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

AP2S1: 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 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 small subunit family. 2 isoforms of the human protein are produced by alternative splicing.

Chromosomal Location of Human Ortholog: 19q13.32

Cellular Component: AP-2 adaptor complex; cytosol; plasma membrane

Molecular Function: protein binding; protein transporter activity; transporter activity

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; regulation of endocytosis; synaptic transmission; viral reproduction

Disease: Hypocalciuric Hypercalcemia, Familial, Type Iii