title: Involvement of retinoblastoma family members and E2F/DP complexes in the death of neurons evoked by DNA damage.
abstract: Neuronal death evoked by DNA damage requires cyclin-dependent kinase 4 (Cdk4) and 6 activity and is accompanied by elevation of cyclin D1-associated kinase activity. Because Cdk4/6 phosphorylates retinoblastoma protein (pRb) family members that then modulate the transcriptional activity of E2F/DP1 complexes, we examined the involvement of these components in DNA damage-evoked neuronal death. Camptothecin induced rapid pRb and p107 phosphorylation at a Cdk4/6 phosphorylation site followed by selective loss of Rb and p107. The CDK inhibitor flavopiridol suppressed pRb and p107 phosphorylation and loss, implicating CDK activity in these events. Moreover, the loss of pRb and p107 appeared to be mediated by caspases because it was blocked by general caspase inhibitors. The role of phosphorylation and pRb and p107 loss in the death pathway was indicated by observations that virally mediated expression of pRb mutated at sites of phosphorylation, including the Cdk4/6 site, inhibited death. Finally, expression of dominant-negative versions of DP1, known to compromise E2F transcriptional activity, protects cortical neurons from death induced by camptothecin and sympathetic neurons from death evoked by UV treatment. Taken together, these results implicate the CDK-pRb/E2F/DP pathway as a required element in the neuronal death evoked by DNA damage.
authors.affiliation: Neuroscience Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8M5, Canada. dpark@uottawa.ca
authors.forename: D S
authors.initials: DS
authors.lastname: Park
authors.forename: E J
authors.initials: EJ
authors.lastname: Morris
authors.forename: R
authors.initials: R
authors.lastname: Bremner
authors.forename: E
authors.initials: E
authors.lastname: Keramaris
authors.forename: J
authors.initials: J
authors.lastname: Padmanabhan
authors.forename: M
authors.initials: M
authors.lastname: Rosenbaum
authors.forename: M L
authors.initials: ML
authors.lastname: Shelanski
authors.forename: H M
authors.initials: HM
authors.lastname: Geller
authors.forename: L A
authors.initials: LA
authors.lastname: Greene
mesh_terms: D000818:Animals; D002166:Camptothecin / Q000494:pharmacology; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D016923:Cell Death / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology; D019938:Cyclin D1 / Q000187:drug effects / Q000378:metabolism; D019927:Cyclin E / Q000187:drug effects / Q000378:metabolism; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases / Q000187:drug effects / Q000378:metabolism*; D004249:DNA Damage / Q000187:drug effects / Q000502:physiology*; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D009687:Nuclear Proteins / Q000187:drug effects / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000187:drug effects / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D051381:Rats; D016160:Retinoblastoma Protein / Q000502:physiology; D056465:Retinoblastoma-Binding Protein 1; D050720:Retinoblastoma-Like Protein p107; D050680:Transcription Factor DP1; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism*
chemical_list: C533431:Arid4a protein, mouse; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D019927:Cyclin E; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D004791:Enzyme Inhibitors; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C493844:RBL1 protein, human; C489485:Rbl1 protein, mouse; D016160:Retinoblastoma Protein; D056465:Retinoblastoma-Binding Protein 1; D050720:Retinoblastoma-Like Protein p107; C493735:TFDP1 protein, human; C493736:Tfdp1 protein, mouse; D050680:Transcription Factor DP1; D014157:Transcription Factors; D019938:Cyclin D1; D017346:Protein Serine-Threonine Kinases; C495900:CDK4 protein, human; C495911:CDK6 protein, human; C495902:Cdk4 protein, mouse; C495903:Cdk4 protein, rat; C495912:Cdk6 protein, mouse; C495913:Cdk6 protein, rat; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D018844:Cyclin-Dependent Kinases; D002166:Camptothecin