title: Cdk phosphorylation triggers sequential intramolecular interactions that progressively block Rb functions as cells move through G1.
abstract: We present evidence that phosphorylation of the C-terminal region of Rb by Cdk4/6 initiates successive intramolecular interactions between the C-terminal region and the central pocket. The initial interaction displaces histone deacetylase from the pocket, blocking active transcriptional repression by Rb. This facilitates a second interaction that leads to phosphorylation of the pocket by Cdk2 and disruption of pocket structure. These intramolecular interactions provide a molecular basis for sequential phosphorylation of Rb by Cdk4/6 and Cdk2. Cdk4/6 is activated early in G1, blocking active repression by Rb. However, it is not until near the end of G1, when cyclin E is expressed and Cdk2 is activated, that Rb is prevented from binding and inactivating E2F.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Harbour
authors.forename: R X
authors.initials: RX
authors.lastname: Luo
authors.forename: A
authors.initials: A
authors.lastname: Dei Santi
authors.forename: A A
authors.initials: AA
authors.lastname: Postigo
authors.forename: D C
authors.initials: DC
authors.lastname: Dean
mesh_terms: D042846:CDC2-CDC28 Kinases; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D005260:Female; D016193:G1 Phase / Q000502:physiology*; D005786:Gene Expression Regulation; D006655:Histone Deacetylases / Q000378:metabolism; D006801:Humans; D008239:Lysine; D009154:Mutation; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein / Q000235:genetics / Q000378:metabolism*; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019927:Cyclin E; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050680:Transcription Factor DP1; D014157:Transcription Factors; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495900:CDK4 protein, human; C495911:CDK6 protein, human; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases; D006655:Histone Deacetylases; D008239:Lysine