Fig. 3

USP1 deubiquitinates and stabilizes RPS16. a HepG2 cells were exposed to ML323 in the absence or presence of BTZ (50 nM) for 24 h. The expression level of RPS16 was determined by western blot. b Quantification of the bands are shown. c HepG2 and HCCLM3 cells were exposed to cycloheximide (CHX, 50 µg/ml) for indicated time with or without the pretreatment of ML323 (for 24 h). The expression level of RPS16 was determined by western blot. d Quantification of the bands are shown. e HepG2 and HCCLM3 cells were exposed to CHX for indicated time with or without the pretreatment of USP1 siRNAs (for 48 h). The expression level of RPS16 was determined by western blot. (f) Quantification of the bands are shown. g RPS16 was immunoprecipitated from HepG2 cells stably expressing USP1 shRNAs or control shRNAs and immunoblotted to K48-linked ubiquitin and RPS16. MG132 (10 µM) was used to treat HepG2 cells for 6 h before harvest. h RPS16 was immunoprecipitated from HepG2 cells transfected with FLAG-USP1-WT, FLAG-USP1-C90A, or control plasmids, and immunoblotted to K48-linked ubiquitin and RPS16