Transporter associated with antigen processing

The antigen peptide transporter ( TAP short of transporter associated with antigen processing) is a protein complex composed of two proteins, which is localized in the membrane of the ER, and is found in animals and fungi. TAP catalyzes the import of peptides from the cytosol into the lumen of the ER during antigen presentation. It is a transport protein of the family of ABC transporters.

Structurally, the TAP protein is a heterodimer consisting of a transmembrane domain, and a nucleotide binding domain. In the context of antigen presentation, as soon as an antigen via a TAP is introduced into the ER, the peptide incorporated into the peptide- binding pocket of the MHC class I complex (if it fits ), and transported to the export from the ER to the cell surface.

Mutations in TAP1 or TAP2 gene may lead to BLS1, a rare disorder of the immune system.

Protein isoform ATP-binding cassette transporter Transportprotein Digital Object Identifier
3542
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