Figure 3.

Effect of wild-type Hdm2 and its mutants on p53 stability. 2KO cells were cotransfected with p53 expression plasmid and the plasmids encoding either wild-type Hdm2 or its mutants as indicated above the figure. At 24 hours after transfection, steady-state levels of p53 (A) and Hdm2 (B) were determined by immunoblotting as described in Materials and Methods. Two species of the Hdm2 protein with different molecular weights were detected (B). This may be a result of different levels of phosphorylation or some other posttranslational modification. The apparent molecular weight of Hdm2Δ150–230 is lower than that of the full-length Hdm2 proteins because of the deletion (B, lane 7).