SEC61-MEDIATED TRANSFER OF A MEMBRANE-PROTEIN FROM THE ENDOPLASMIC-RETICULUM TO THE PROTEASOME FOR DESTRUCTION

The human cytomegalovirus genome encodes proteins that trigger destruc tion of newly synthesized major histocompatibility complex (MHC) class I molecules. The human cytomegalovirus gene US2 specifies a product c apable of dislocating MHC class I molecules from the endoplasmic retic ulum to the cytosol and delivering them to the proteasome. This proces s involves the Sec61 complex, in what appears to be a reversal of the reaction by which it translocates nascent chains into the endoplasmic reticulum.