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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
12
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pubmed:dateCreated |
2005-3-21
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pubmed:abstractText |
Chk2 is a critical mediator of diverse cellular responses to DNA damage. Activation of Chk2 by DNA damage requires phosphorylation at sites including Thr68. In earlier work, we found that an activity present in rabbit reticulocyte lysates phosphorylates and activates Chk2. We now find that hypophosphorylated Chk2 can be phosphorylated at Thr68 by various subcellular fractions of HEK293 cells. This activity is sensitive to the phosphatidylinositol 3'-kinase-like kinase inhibitor wortmannin, but not to caffeine. DNA enhances the Chk2 phosphorylation by cellular fractions in vitro. The wortmannin-sensitive Chk2 kinase activity is present in fractions from ATM-deficient cells. In contrast, Chk2 was not efficiently phosphorylated at Thr68 in vitro by fractions from cells with a defective DNA-dependent protein kinase (DNA-PK) catalytic subunit. Chk2 is phosphorylated by purified DNA-PK in vitro. Endogenous Chk2 coimmunoprecipitates Ku70 and Ku80. In a series of matched cell lines having and lacking functional DNA-PK, Chk2 activation by exposure of cells to ionizing radiation, or to camptothecin was consistently diminished in the absence of DNA-PK. Down-regulation of DNA-PK(cs) by either siRNA or a chemical inhibitor attenuated radiation-induced Chk2 phosphorylation. Ionizing radiation-induced Chk2 phosphorylation was wortmannin-sensitive in ATM-defective cells with depleted ATR. These results suggest that DNA-PK augments ATM and ATR in activation of Chk2 by DNA damage.
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pubmed:grant |
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/ATR protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Androstadienes,
http://linkedlifedata.com/resource/pubmed/chemical/Antigens, Nuclear,
http://linkedlifedata.com/resource/pubmed/chemical/Cell Cycle Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/DNA,
http://linkedlifedata.com/resource/pubmed/chemical/DNA-Activated Protein Kinase,
http://linkedlifedata.com/resource/pubmed/chemical/DNA-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Ku autoantigen,
http://linkedlifedata.com/resource/pubmed/chemical/Nuclear Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/PRKDC protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Protein-Serine-Threonine Kinases,
http://linkedlifedata.com/resource/pubmed/chemical/Tumor Suppressor Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/ataxia telangiectasia mutated...,
http://linkedlifedata.com/resource/pubmed/chemical/checkpoint kinase 2,
http://linkedlifedata.com/resource/pubmed/chemical/wortmannin
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9258
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
280
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
12041-50
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pubmed:dateRevised |
2011-11-2
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pubmed:meshHeading |
pubmed-meshheading:15668230-Androstadienes,
pubmed-meshheading:15668230-Antigens, Nuclear,
pubmed-meshheading:15668230-Cell Cycle Proteins,
pubmed-meshheading:15668230-Cells, Cultured,
pubmed-meshheading:15668230-DNA,
pubmed-meshheading:15668230-DNA Damage,
pubmed-meshheading:15668230-DNA-Activated Protein Kinase,
pubmed-meshheading:15668230-DNA-Binding Proteins,
pubmed-meshheading:15668230-Enzyme Activation,
pubmed-meshheading:15668230-Humans,
pubmed-meshheading:15668230-Nuclear Proteins,
pubmed-meshheading:15668230-Phosphorylation,
pubmed-meshheading:15668230-Protein-Serine-Threonine Kinases,
pubmed-meshheading:15668230-Tumor Suppressor Proteins
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pubmed:year |
2005
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pubmed:articleTitle |
Regulation of CHK2 by DNA-dependent protein kinase.
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pubmed:affiliation |
Department of Pathology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.
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