Premium
The first N‐terminal transmembrane helix of each subunit of the antigenic peptide transporter TAP is essential for independent tapasin binding
Author(s) -
Koch Joachim,
Guntrum Renate,
Tampé Robert
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.06.053
Subject(s) - transporter associated with antigen processing , endoplasmic reticulum , microbiology and biotechnology , mhc class i , transmembrane domain , transmembrane protein , chemistry , biochemistry , peptide , biology , major histocompatibility complex , amino acid , gene , receptor
The heterodimeric ABC transporter TAP translocates proteasomal degradation products from the cytosol into the lumen of the endoplasmic reticulum, where these peptides are loaded onto MHC class I molecules by a macromolecular peptide‐loading complex (PLC) and subsequently shuttled to the cell surface for inspection by cytotoxic T lymphocytes. Tapasin recruits, as a central adapter protein, other components of the PLC at the unique N‐terminal domains of TAP. We found that the N‐terminal domains of human TAP1 and TAP2 can independently bind to tapasin, thus providing two separate loading platforms for PLC assembly. Moreover, tapasin binding is dependent on the first N‐terminal transmembrane helix of TAP1 and TAP2, demonstrating that these two helices contribute independently to the recruitment of tapasin and associated factors.