PIAS2 modulates the stability of the HCV core, NS3 and NS5A proteins. (A,B) 293T cells were transfected with siNC or siPIAS2 and then transfected with the indicated HCV protein expression plasmids. The expression levels of the HCV proteins were detected at 48 h post-transfection. The relative density of the blots from three independent experiments were analyzed by densitometry and shown in panel (B); (C,D) 293T cells were transfected with pHA-Vector or pHA-PIAS2, HCV protein expression plasmids, and pCer-SUMO1. The HCV protein expression levels were detected at 48 h post-transfection. The relative density of the blots from three independent experiments was analyzed by densitometry and shown in panel (D); (E) Huh7 cells were transfected with siNC or siPIAS2 and then infected with J399EM at an MOI of 0.1 for 72 h. The cells were treated with cycloheximide (CHX) (100 μg/mL), and protein samples were collected at the indicated time points to evaluate the protein expression levels as indicated; (F) the relative density of the blots from three independent experiments was analyzed by densitometry and normalized to actin. To show the degradation rate, the samples without CHX treatment in each group were set to 1, * p < 0.05.