[PDF][PDF] A viral ER-resident glycoprotein inactivates the MHC-encoded peptide transporter
H Hengel, JO Koopmann, T Flohr, W Muranyi… - Immunity, 1997 - cell.com
Immunity, 1997•cell.com
Human cytomegalovirus inhibits peptide import into the endoplasmic reticulum (ER) by the
MHC-encoded TAP peptide transporter. We identified the open reading frame US6 to
mediate this effect. Expression of the 21 kDa US6 glycoprotein in human cytomegalovirus–
infected cells correlates with the inhibition of peptide transport during infection. The
subcellular localization of US6 is ER restricted and is identical with TAP. US6 protein is
found in complexes with TAP1/2, MHC class I heavy chain, β 2-microglobulin, calnexin …
MHC-encoded TAP peptide transporter. We identified the open reading frame US6 to
mediate this effect. Expression of the 21 kDa US6 glycoprotein in human cytomegalovirus–
infected cells correlates with the inhibition of peptide transport during infection. The
subcellular localization of US6 is ER restricted and is identical with TAP. US6 protein is
found in complexes with TAP1/2, MHC class I heavy chain, β 2-microglobulin, calnexin …
Abstract
Human cytomegalovirus inhibits peptide import into the endoplasmic reticulum (ER) by the MHC-encoded TAP peptide transporter. We identified the open reading frame US6 to mediate this effect. Expression of the 21 kDa US6 glycoprotein in human cytomegalovirus–infected cells correlates with the inhibition of peptide transport during infection. The subcellular localization of US6 is ER restricted and is identical with TAP. US6 protein is found in complexes with TAP1/2, MHC class I heavy chain, β2-microglobulin, calnexin, calreticulin, and tapasin. TAP inhibition, however, is independent of the presence of class I heavy chain and tapasin. The results establish a new mechanism for viral immune escape and a novel role for ER-resident proteins to regulate TAP via its luminal face.
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