Figure 3

GSK3β regulates p53 transcriptional activity. (A) SAOS-2 cells were transiently transfected with vector (pcDNA3.1), or expression vectors for wtp53, wtp53S33A (S33A) or wtp53S37A (S37A). p53 expression was detected by western blotting. (B+C). SAOS-2 cells were transiently transfected with p50-2, a p53-responsive luciferase reporter construct, and 50 ng of vector (Con), wtp53, wtp53S33A (S33A), or wtp53S37A (S37A) as indicated, β-galactosidase activity from pCMV-Gal was used to adjust for transfection efficiency. In (B), the actual transcriptional activity of each p53 construct is shown. In (C), cells were cotransfected with an expression vector for GSK3β (pcDGSKSβ ; 800 ng). The transcriptional activity was calculated by dividing p53 activity in the presence of GSK3b by p53 activity in the absence of GSK3b and expressing the answer as a percentage. 0% = no increase