Figure 6

RPN2 is a common interactor of VAPB and FAF1. (A) Flag-VAPB and Flag-FAF1 were immunoprecipitated from U2OS cells treated with 10 μM MG132 for 2 hr, 5 μM MG132 for 6 hr or left untreated (0 hr). Asterisks indicate non-specific bands. (B) Proteasome inhibition enhances RPN2 binding to endogenous VAPB. Endogenous VAPB was immunoprecipitated from U2OS cells treated with 10 μM MG132 for 2 hr or left untreated (0 hr). (C) ER stress induced by tunicamycin treatment does not affect RPN2 levels or its binding to VAPB. Endogenous VAPB was immunoprecipitated from U2OS cells treated with 5 μg/ml tunicamycin for 5 h, 10 μM MG132 for 2 hr, both tunicamycin and MG132, or dimethyl sulfoxide as a control. DMSO, dimethyl sulfoxide; IP, immunoprecipitate; MG, MG132.