J. HeLa cells stably transfected with Ctrl, HSP70 or HSC70 shRNA, treated with DMSO or MG132 for 8 hours, then washed and cultured for 3 days. Immunoblot analysis of the cells is shown in (J). The up-regulation of p53 and p21 at 3 days after pulse treatment with MG132 was alleviated by HSC70 knockdown, although the basal level of p53 in HSC70 knockdown cells is higher than that in control cells. Both p53 and p21 were up-regulated in HSP70 knockdown cells treated with or without MG132. 