The C-terminal region of the hepatitis C virus E1 glycoprotein confers localization within the endoplasmic reticulum

Expression of the hepatitis C virus glycoprotein E1 in cultured cells localizes it to the endoplasmic reticulum, suggesting that E1 contains a signal mediating retention. Fusion of the C-terminal region of E1 to the ectodomain of CD4 prevented it from being transported to the cell surface. Fusion of this region of E1 resulted in localization of CD4 and influenza virus haemagglutinin chimeric molecules to a pre-medial Golgi compartment. This signal was present within E1 residues 311-383. Retention was not due to misfolding since the chimeric molecules did not form disulphide-linked aggregates indicative of misfolded proteins, and could be recognized by MAbs specific for conformational epitopes.