title: Chk2 activates E2F-1 in response to DNA damage.
abstract: The E2F-1 transcription factor is regulated during cell cycle progression and induced by cellular stress, such as DNA damage. We report that checkpoint kinase 2 (Chk2) regulates E2F-1 activity in response to the DNA-damaging agent etoposide. A Chk2 consensus phosphorylation site in E2F-1 is phosphorylated in response to DNA damage, resulting in protein stabilization, increased half-life, transcriptional activation and localization of phosphorylated E2F-1 to discrete nuclear structures. Expression of a dominant-negative Chk2 mutant blocks induction of E2F-1 and prevents E2F-1-dependent apoptosis. Moreover, E2F-1 is resistant to induction by etoposide in tumour cells expressing mutant chk2. Therefore, Chk2 phosphorylates and activates E2F-1 in response to DNA damage, resulting in apoptosis. These results suggest a role for E2F-1 in checkpoint control and provide a plausible explanation for the tumour suppressor activity of E2F-1.
authors.affiliation: Division of Biochemistry and Molecular Biology, Davidson Building, University of Glasgow, Glasgow, G12 8QQ, UK.
authors.forename: Craig
authors.initials: C
authors.lastname: Stevens
authors.forename: Linda
authors.initials: L
authors.lastname: Smith
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: La Thangue
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics; D018797:Cell Cycle Proteins; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D004249:DNA Damage / Q000235:genetics*; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005047:Etoposide / Q000494:pharmacology; D005057:Eukaryotic Cells / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D009154:Mutation / Q000235:genetics; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D019384:Nucleic Acid Synthesis Inhibitors; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; D012694:Serine; D005047:Etoposide; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases