Fig. 3.

Model of cell fate decision. There are two forms of active p53: p53 arrester and p53 killer. p53 arrester regulates the expression of Wip1, p53DINP1, and p21, whereas p53 killer controls the expression of p53DINP1 and p53AIP1. CytoC and Casp3 are the pro-apoptotic components. There is a positive-feedback loop between CytoC and Casp3, which creates an apoptotic switch. The release of CytoC leads to activation of Casp3, which in turn cleaves the inhibitors of p53AIP1 (such as Bcl-2 and Bcl-xL) to enhance the release of CytoC.