FEATURES

FAMILY

DESCRIPTION

Also known as TAP1_RAT, Tap1, Abcb2, Mtp1. ABC transporter associated with antigen processing (PubMed:17018292). In complex with TAP2 mediates unidirectional translocation of peptide antigens from cytosol to endoplasmic reticulum (ER) for loading onto MHC class I (MHCI) molecules (By similarity). Uses the chemical energy of ATP to export peptides against the concentration gradient (By similarity). 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 (By similarity). As a component of the peptide loading complex (PLC), acts as a molecular scaffold essential for peptide-MHCI assembly and antigen presentation (By similarity). Heterodimer of TAP1 and TAP2 (TAP1-TAP2). A component of the peptide loading complex (PLC), interacts via TAPBP with MHCI heterodimer; this interaction mediates peptide-MHCI assembly. Interacts with PSMB5 and PSMB8.

EXTERNAL LINKS

Tap1

Antigen peptide transporter 1

Tap1

Molecular Synopsis