β-catenin protein is accumulated in Grp58 knockdown cells. Grp58 and β-catenin protein levels in stable Grp58 knockdown cells were determined using Western blot (A, C and D) and qRT-PCR (B). (C) Cells were pretreated with vehicle control (DMSO) or MG132 for 4 h before harvest. (D) β-Catenin degradation assay. After pre-treatment with MG132 for 4 h, the medium was refreshed. Cells were subsequently treated with CHX and harvested at the indicated time-points. L#1 and L#2, HeLa cell lines stably expressing luciferase shRNA; G#1 and G#2, HeLa cell lines stably expressing Grp58 shRNA.