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An Overlapping Kinase and Phosphatase Docking Site Regulates Activity of the Retinoblastoma Protein
The phosphorylation state and corresponding activity of the retinoblastoma tumor suppressor protein (Rb) are modulated by a balance of kinase and phosphatase activities. Here we characterize the association of Rb with the catalytic subunit of protein phosphatase 1 (PP1c). A crystal structure identif...
Autores principales: | , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2933323/ https://www.ncbi.nlm.nih.gov/pubmed/20694007 http://dx.doi.org/10.1038/nsmb.1868 |
Sumario: | The phosphorylation state and corresponding activity of the retinoblastoma tumor suppressor protein (Rb) are modulated by a balance of kinase and phosphatase activities. Here we characterize the association of Rb with the catalytic subunit of protein phosphatase 1 (PP1c). A crystal structure identifies an enzyme-docking site in the Rb C-terminal domain that is required for efficient PP1c activity towards Rb. The phosphatase-docking site overlaps with the known docking site for Cyclin dependent kinase, and PP1 competition with Cdk-Cyclins for Rb binding is sufficient to retain Rb activity and block cell cycle advancement. These results provide the first detailed molecular insights into Rb activation and establish a novel mechanism for Rb regulation in which kinase and phosphatase compete for substrate docking. |
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