Anti-AP2M1 Antibody Picoband® Fluoro488 Conjugated

AP-2 complex subunit mu is a protein that in humans is encoded by the AP2M1 gene. This gene encodes a subunit of the heterotetrameric coat assembly protein complex 2 (AP2), which belongs to the adaptor complexes medium subunits family. The encoded protein is required for the activity of a vacuolar ATPase, which is responsible for proton pumping occurring in the acidification of endosomes and lysosomes. The encoded protein may also play an important role in regulating the intracellular trafficking and function of CTLA-4 protein. Three transcript variants encoding different isoforms have been found for this gene.

AP-2 complex subunit mu; AP-2 mu chain; Adaptin-mu2; Adaptor protein complex AP-2 subunit mu; Adaptor-related protein complex 2 subunit mu; Clathrin assembly protein complex 2 mu medium chain; Clathrin coat assembly protein AP50; Clathrin coat-associated protein AP50; HA2 50 kDa subunit; Plasma membrane adaptor AP-2 50 kDa protein; AP2M1; CLAPM1, KIAA0109

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 ly to membrane components. Clathrin-associated adaptor protein (AP) complexes which can bind ly 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 mu subunit binds to transmembrane cargo proteins; it recognizes the Y-X-X-Phi motifs. The surface region interacting with to the Y-X- X-Phi motif is inaccessible in cytosolic AP-2, but becomes accessible through a conformational change following phosphorylation of AP-2 mu subunit at 'Tyr-156' in membrane- associated AP-2. The membrane-specific phosphorylation event appears to involve assembled clathrin which activates the AP-2 mu kinase AAK1 (By similarity) . Plays a role in endocytosis of frizzled family members upon Wnt signaling (By similarity) . .

1. Entrez Gene: AP2M1 adaptor-related protein complex 2, mu 1 subunit. 2. Druck T, Gu Y, Prabhala G, Cannizzaro LA, Park SH, Huebner K, Keen JH (Nov 1995) . Chromosome localization of human genes for clathrin adaptor polypeptides AP2 beta and AP50 and the clathrin-binding protein, VCP. Genomics. 30 (1) : 94–7. 3. Follows ER, McPheat JC, Minshull C, Moore NC, Pauptit RA, Rowsell S, Stacey CL, Stanway JJ, Taylor IW, Abbott WM (Oct 2001) . Study of the interaction of the medium chain mu 2 subunit of the clathrin-associated adapter protein complex 2 with cytotoxic T-lymphocyte antigen 4 and CD28. The Biochemical Journal. 359 (Pt 2) : 427–34.

Cell membrane. Membrane, coated pit; Peripheral membrane protein; Cytoplasmic side. AP-2 appears to be excluded from internalizing CCVs and to disengage from sites of endocytosis seconds before internalization of the nascent CCV. .