FEATURES

FAMILY

DESCRIPTION

Also known as TAP1_HUMAN, TAP1, ABCB2, PSF1, RING4, Y3. ABC transporter associated with antigen processing. In complex with TAP2 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (PubMed:25656091, PubMed:25377891). Uses the chemical energy of ATP to export peptides against the concentration gradient (PubMed:25377891). During the transport cycle alternates between 'inward-facing' state with peptide binding site facing the cytosol to 'outward-facing' state with peptide binding site facing the ER lumen. Peptide antigen binding to ATP-loaded TAP1-TAP2 induces a switch to hydrolysis-competent 'outward-facing' conformation ready for peptide loading onto nascent MHCI molecules. Subsequently ATP hydrolysis resets the transporter to the 'inward facing' state for a new cycle (PubMed:25377891, PubMed:25656091, PubMed:11274390). Typically transports intracellular peptide antigens of 8 to 13 amino acids that arise from cytosolic proteolysis via IFNG-induced immunoproteasome. Binds peptides with free N- and C-termini, the first three and the C-terminal residues being critical. Preferentially selects peptides having a highly hydrophobic residue at position 3 and hydrophobic or charged residues at the C-terminal anchor. Proline at position 2 has the most destabilizing effect (PubMed:7500034, PubMed:9256420, PubMed:11274390). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (PubMed:26611325, PubMed:1538751, PubMed:25377891). Heterodimer of TAP1 and TAP2 (TAP1-TAP2) (PubMed:1538751). A component of the peptide loading complex (PLC), interacts via TAPBP with MHCI heterodimer; this interaction mediates peptide-MHCI assembly (PubMed:26611325). Recruits TAPBP in a 1:1 stoichiometry (PubMed:22638925). Interacts with classical MHCI such as HLA-A*02-B2M; this interaction is obligatory for the loading of peptide epitopes (PubMed:8805302, PubMed:8630735). Interacts with non-classical MHCI molecules including HLA-E-B2M and HLA-F-B2M as well as PLC component CALR before the peptide loading (PubMed:9427624, PubMed:10605026). Interacts with PSMB5 and PSMB8 (PubMed:15488952).

Also known as TAP1_HUMAN, TAP1, ABCB2, PSF1, RING4, Y3. ABC transporter associated with antigen processing. In complex with TAP2 mediates unidirectional translocation of peptide antigens from cyt ...

EXTERNAL LINKS

TAP1

Antigen peptide transporter 1

TAP1

Molecular Synopsis