title: Rapid destruction of human Cdc25A in response to DNA damage.
abstract: To protect genome integrity and ensure survival, eukaryotic cells exposed to genotoxic stress cease proliferating to provide time for DNA repair. Human cells responded to ultraviolet light or ionizing radiation by rapid, ubiquitin- and proteasome-dependent protein degradation of Cdc25A, a phosphatase that is required for progression from G1 to S phase of the cell cycle. This response involved activated Chk1 protein kinase but not the p53 pathway, and the persisting inhibitory tyrosine phosphorylation of Cdk2 blocked entry into S phase and DNA replication. Overexpression of Cdc25A bypassed this mechanism, leading to enhanced DNA damage and decreased cell survival. These results identify specific degradation of Cdc25A as part of the DNA damage checkpoint mechanism and suggest how Cdc25A overexpression in human cancers might contribute to tumorigenesis.
authors.affiliation: Institute of Cancer Biology, Danish Cancer Society, Strandboulevarden 49, DK-2100 Copenhagen, Denmark.
authors.forename: N
authors.initials: N
authors.lastname: Mailand
authors.forename: J
authors.initials: J
authors.lastname: Falck
authors.forename: C
authors.initials: C
authors.lastname: Lukas
authors.forename: R G
authors.initials: RG
authors.lastname: Syljuâsen
authors.forename: M
authors.initials: M
authors.lastname: Welcker
authors.forename: J
authors.initials: J
authors.lastname: Bartek
authors.forename: J
authors.initials: J
authors.lastname: Lukas
mesh_terms: D042846:CDC2-CDC28 Kinases; D002460:Cell Line; D002470:Cell Survival; D000071877:Checkpoint Kinase 1; D019927:Cyclin E / Q000378:metabolism; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004249:DNA Damage; D004260:DNA Repair; D004261:DNA Replication; D016193:G1 Phase; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016196:S Phase; D014162:Transfection; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays; D020687:cdc25 Phosphatases / Q000235:genetics / Q000378:metabolism*
chemical_list: D019927:Cyclin E; D009097:Multienzyme Complexes; D047428:Protein Kinase Inhibitors; D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D019000:Phosphotyrosine; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; C517004:CDC25A protein, human; D020687:cdc25 Phosphatases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex