Figure 6.
Rb phosphorylation promotes transcription of E2F responsive genes. Rb normally binds E2F transcription factors and their dimerization partners. When phosphorylated by cyclin/CDK heterodimers, Rb loses affinity for E2F and free E2F is allowed to promote transcription. Rb is dephosphorylated at the end of mitosis, allowing reassociation with E2F. Normally, PP1 dephosphorylates Rb at the end of mitosis, but PP2A-PR70 can dephosphorylate Rb under oxidative stress conditions. (see colour version of this figure at www.informahealthcare.com/bmg).