antigen peptide transporter-2 (APT2), peptide transporter TAP2, peptide transporter PSF2, peptide supply factor 2 (PSF-2), RING11, Y1, PSF2, MTP-2 or HAM-2

^[1]^[2]^[3]

Function

pump which delivers peptides to class 1 MHC molecules within the endoplasmic reticulum of antigen presenting cells
role in the transport of antigens from the cytoplasm to the endoplasmic reticulum for association with MHC class 1 molecules
acts as a molecular scaffold for final stage of MHC class 1 folding, binding of peptide
nascent MHC class 1 molecules associate with TAP via tapasin
inhibited by covalent attachment of herpes simplex virus ICP47 protein, which blocks peptide-binding site of TAP
inhibited by human cytomegalovirus US6 glycoprotein, which binds to the lumenal side of the TAP complex & inhibits peptide translocation by specifically blocking ATP-binding to TAP1 & prevents the conformational rearrangement of TAP induced by peptide binding
inhibited by human adenovirus E3-19K glycoprotein, which binds the TAP complex & acts as a tapasin inhibitor, preventing MHC class 1/TAP association
heterodimer of TAP1 & TAP2

peptide-binding site is shared between the cytoplasmic loops of TAP1 & TAP2
belongs to the ABC transporter family, MHC peptide exporter (TC 3.A.1.209) subfamily
contains 1 ABC transmembrane type-1 domain
contains 1 ABC transporter domain

defects in TAP2 are a cause of bare lymphocyte syndrome
allele TAP2*Bky2, commonly found only in the Japanese may be associated with susceptibility to Sjoegren syndrome

4 common alleles are officially recognized:
- TAP2*0101 (TAP2A or PSF2A or RING11A)
- TAP2*0102 (TAP2E),
- TAP2*0103 (TAP2F)
- TAP2*0201 (TAP2B or PSF2B or RING11B)
other relatively common alleles have been identified: TAP2*01D, TAP2*01E, TAP2*01F, TAP2*01G, TAP2*01H, TAP2*02B, TAP2*02C (TAP2*0202), TAP2*02D, TAP2*02E, TAP2*02F, TAP2*03A & TAP2*04A
allele TAP2*Bky2 is commonly found only in the Japanese population