TAP is an integral transmembrane protein involved in the transport of antigens from the cytoplasm to the endoplasmic reticulum for association with MHC class I molecules. It is a heterodimer of TAP1 and TAP2, and the peptide-binding site is shared between the cytoplasmic loops of TAP1 and TAP2. TAP is inducible by interferon gamma and belongs to the ABC transporter family, MDR subfamily. TAP also acts as a molecular scaffold for the final stage of MHC class I folding, namely the binding of