Addition of furin convertase inhibitor does not lead to a buildup of Endo H–resistant HJV in the cell lysate. HJV-HepG2 cells in 35-mm dishes were pretreated with no inhibitor (control) or with furin convertase inhibitor (FCI, 5 μM decanoyl-Arg-Val-Lys-Arg-chloromethylketone) for 90 minutes. Cells were then metabolically labeled for 2 hours in the presence and absence of inhibitor. Cells were washed, lysed, and immunoprecipitated using the anti-HJV antibody and subjected to Endo H digestion as described in “Methods.” These data are representative of 2 experiments.