Structures of inactive retinoblastoma protein reveal multiple mechanisms for cell cycle control
- UCSC
Cyclin-dependent kinase (Cdk) phosphorylation of the Retinoblastoma protein (Rb) drives cell proliferation through inhibition of Rb complexes with E2F transcription factors and other regulatory proteins. We present the first structures of phosphorylated Rb that reveal the mechanism of its inactivation. S608 phosphorylation orders a flexible 'pocket' domain loop such that it mimics and directly blocks E2F transactivation domain (E2F{sup TD}) binding. T373 phosphorylation induces a global conformational change that associates the pocket and N-terminal domains (RbN). This first multidomain Rb structure demonstrates a novel role for RbN in allosterically inhibiting the E2F{sup TD}-pocket association and protein binding to the pocket 'LxCxE' site. Together, these structures detail the regulatory mechanism for a canonical growth-repressive complex and provide a novel example of how multisite Cdk phosphorylation induces diverse structural changes to influence cell cycle signaling.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- DOE - BASIC ENERGY SCIENCESNIH
- OSTI ID:
- 1045688
- Journal Information:
- Genes and Development, Journal Name: Genes and Development Journal Issue: 11 Vol. 26; ISSN 0890-9369; ISSN GEDEEP
- Country of Publication:
- United States
- Language:
- ENGLISH
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