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. Author manuscript; available in PMC: 2013 Aug 8.
Published in final edited form as: Cell. 2009 May 15;137(4):609–622. doi: 10.1016/j.cell.2009.04.050

Figure 2. Classical Model of p53 Activation.

Figure 2

The classical model for p53 activation generally consists of three sequential activating steps: (1) stress-induced stabilization mediated by phosphorylation (P), (2) DNA binding, and (3) recruitment of the general transcriptional machinery. During normal homeostasis, p53 is degraded after Mdm2-mediated ubiquitination (left), while stress signal-induced p53 phosphorylation by ATM, ATR, and other kinases stabilizes p53 and promotes DNA binding. DNA-bound p53 then recruits the transcriptional machinery to activate transcription of p53 target genes.