"the central module is the interplay between p53 and the Mdm2 protein, which inactivates p53 and targets it for rapid proteolysis."
"The interaction of MDM2 with p53 inhibits p53 transcriptional activity and targets p53 for ubiquitin-dependent degradation. The ability of MDM2 to inhibit p53 functions is antagonized by the ARF oncosuppressor protein."
"It has been proposed that ARF is expressed only when an E2F signaling threshold is exceeded following oncogenic activation. The main activity of ARF is its ability to bind to p53 inhibitors and to control ribosome biogenesis. Human double minute (HDM2) [mouse double minute 2 (Mdm2) in mouse] and ARF protein binding 1 (BP1)/Mule are two specific E3 ubiquitin ligases that mediate p53 degradation through ubiquitination."
"Akt (PKB) directly phosphorylates multiple protein targets of relevance to apoptosis (Figure 2B), suppressing cell death clearly within the intrinsic pathway (e.g., BAD inactivation, human caspase-9 suppression) and possibly also the extrinsic pathway (e.g., FasL expression) in some types of cells."