Figure 2. Mutations in the DNA binding domain of p53 enhance mTORC1 activity equivalently to loss of p53.

The expression and phosphorylation of S6K1 and 4EBP1 were determined by immunoblotting of HCT116 p53−/− cells stably transfected with hot spot mutants of p53 (A) or in similarly transfected H1299 cells (B) and compared with HCT116 and their isogenic p53−/− cells or H1299 transfected with an inducible p53 construct, respectively. The binding of 4EBP1 to m⁷GTP bound beads is severely depressed in HCT116 (C) or H1299 cells stably transfected with p53 mutants (D). In (B and D) ind. and unind. refer to induced and uninduced.