p53 is renowned as a cellular tumor suppressor poised to instigate remedial responses to various stress insults that threaten DNA integrity.

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p53 levels and activities are kept under tight regulation involving a complex network of activators and inhibitors, which determine the type and extent of p53 growth inhibitory signaling.

 

Within this complexity, the p53–Mdm2 negative auto-regulatory loop serves as a major route through which intra- and extra-cellular stress signals are channeled to appropriate p53 responses.