title: A Strategy for Direct Chemical Activation of the Retinoblastoma Protein.
abstract: The retinoblastoma (Rb) tumor suppressor protein negatively regulates cell proliferation by binding and inhibiting E2F transcription factors. Rb inactivation occurs in cancer cells upon cyclin-dependent kinase (Cdk) phosphorylation, which induces E2F release and activation of cell cycle genes. We present a strategy for activating phosphorylated Rb with molecules that bind Rb directly and enhance affinity for E2F. We developed a fluorescence polarization assay that can detect the effect of exogenous compounds on modulating affinity of Rb for the E2F transactivation domain. We found that a peptide capable of disrupting the compact inactive Rb conformation increases affinity of the repressive Rb-E2F complex. Our results demonstrate the feasibility of discovering novel molecules that target the cell cycle and proliferation through directly targeting Rb rather than upstream kinase activity.
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: Cameron R
authors: CR
authors: Pye
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: Walter M
authors: WM
authors: Bray
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: Elise R
authors: ER
authors: Brown
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: Jason R
authors: JR
authors: Burke
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: R Scott
authors: RS
authors: Lokey
authors: Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States.
authors: Seth M
authors: SM
authors: Rubin
mesh_terms: D004353:Drug Evaluation, Preclinical; D050684:E2F Transcription Factors / Q000378:metabolism*; D005454:Fluorescence Polarization; D006801:Humans; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D010766:Phosphorylation; D011485:Protein Binding / Q000187:drug effects*; D011487:Protein Conformation / Q000187:drug effects*; D060066:Protein Interaction Maps / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D050684:E2F Transcription Factors; D010455:Peptides; D016160:Retinoblastoma Protein