FIG. 6.

Correlation of Mdm2-mediated degradation to protein stability. The region from amino acids 92 to 112 of p53 is critical for protein stability. U2OS cells were transfected with 2.5 μg of the indicated vector. The cells were treated with cycloheximide (40 μg/ml) at 24 h posttransfection and then harvested at 0, 30, 60, 120, 180, or 300 min later. Lysates from the cells were analyzed by anti-Flag Western blotting (A). Quantitation of the protein as a percentage of the starting levels was derived from a densitometric measurement of the Western blot signals (B).