USP25 reduces levels of ubiquitinated endogenous proteins associated with HRD1 or VCP/p97.

A–C) HEK-293 cells were transfected as indicated. 48 hours later cells were harvested and constructs were immunopurified with bead-bound anti-V5 antibody to isolate V5-HRD1-associated protein (panels A and B), or with bead-bound anti-GFP antibody to isolate GFP-VCP-associated proteins (panel C). We did not detect ubiquitin species in western blots from stringent, denature/renature immunoprecipitations of HRD1 or VCP/p97 using RIPA buffer (data not shown), indicating that the ubiquitin signal we observe in this figure is due to species associated with HRD1 or VCP/p97. Shown are western blots of inputs from whole cells lysates and from immunopurified protein. Histograms are semi-quantifications of results from the left and other similar, independent experiments. Shown are means +/− standard deviations. P values for panels A and C are from Student-T tests.