TAP1 Antibody – Mouse Monoclonal

The membrane-associated protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra- and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This protein is a member of the MDR/TAP subfamily. Members of the MDR/TAP subfamily are involved in multidrug resistance. The protein encoded by this gene is involved in the pumping of degraded cytosolic peptides across the endoplasmic reticulum into the membrane-bound compartment where class I molecules assemble. Mutations in this gene may be associated with ankylosing spondylitis, insulin-dependent diabetes mellitus, and celiac disease. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, May 2014]

TAP1: a 'transporter associated with antigen processing' (TAP) protein. Member of the ATP binding cassette (ABC) family of transmembrane transporters. Also acts as a molecular scaffold for the final stage of MHC class I folding, namely the binding of peptide. Nascent MHC class I molecules associate with TAP via tapasin. Inhibited by the covalent attachment of herpes simplex virus ICP47 protein, which blocks the peptide-binding site of TAP. Inhibited by human cytomegalovirus US6 glycoprotein, which binds to the lumenal side of the TAP complex and inhibits peptide translocation by specifically blocking ATP-binding to TAP1 and prevents the conformational rearrangement of TAP induced by peptide binding. Inhibited by human adenovirus E3-19K glycoprotein, which binds the TAP complex and acts as a tapasin inhibitor, preventing MHC class I/TAP association. Expression of TAP1 is down-regulated by human Epstein-Barr virus vIL-10 protein, thereby affecting the transport of peptides into the endoplasmic reticulum and subsequent peptide loading by MHC class I molecules. Defects in TAP1 are a cause of bare lymphocyte syndrome.

Protein type: Transporter; Membrane protein, integral; Membrane protein, multi-pass

Chromosomal Location of Human Ortholog: 6p21.3

Cellular Component: endoplasmic reticulum membrane; TAP complex; membrane; mitochondrion; integral to membrane; integral to endoplasmic reticulum membrane

Molecular Function: protein binding; protein homodimerization activity; peptide transporter activity; peptide antigen binding; TAP1 binding; ATPase activity, coupled to transmembrane movement of substances; MHC class I protein binding; TAP2 binding; ADP binding; ATP binding; peptide-transporting ATPase activity

Biological Process: peptide transport; intracellular transport of viral proteins in host cell; antigen processing and presentation of peptide antigen via MHC class I; metabolic process; antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent; antigen processing and presentation of exogenous peptide antigen via MHC class I; defense response; antigen processing and presentation of endogenous peptide antigen via MHC class I; transmembrane transport; cytosol to ER transport

Disease: Bare Lymphocyte Syndrome, Type I