Figure 6.

Δ122p53 and Δ133p53α inhibit proteasomal degradation of FLp53. (a) Mouse 3T3 cells transduced with either an empty vector or Δ122p53 were treated with the proteasomal inhibitor MG132 at the indicated concentrations for 4.5 h. Following MG132 treatment, cells were harvested and protein levels determined by immunoblotting. (b) Experiments were repeated using human A549 cells transduced to express Δ133p53α. (c) A549 cells transduced with Δ133p53α or a vector control were treated with 1 μg/ml amsacrine for 0, 4, 8, and 24 h. Following amsacrine treatment, cells were harvested and subjected to immunoprecipitation with the p53 antibody pAb1801, followed by western blotting with a rabbit polyclonal p53 phospho-serine antibody to detect activated p53; the p53 antibody pAb240 to detect Δ133p53α; and SMP14 to detect bound MDM2