Linked Life Data

10744722

Source:http://linkedlifedata.com/resource/pubmed/id/10744722

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
2000-5-8
pubmed:abstractText
Recent evidence indicates that arrest of mammalian cells at the G(2)/M checkpoint involves inactivation and translocation of Cdc25C, which is mediated by phosphorylation of Cdc25C on serine 216. Data obtained with a phospho-specific antibody against serine 216 suggest that activation of the DNA damage checkpoint is accompanied by an increase in serine 216 phosphorylated Cdc25C in the nucleus after exposure of cells to gamma-radiation. Prior treatment of cells with 2 mM caffeine inhibits such a change and markedly reduces radiation-induced ataxia-telangiectasia-mutated (ATM)-dependent Chk2/Cds1 activation and phosphorylation. Chk2/Cds1 is known to localize in the nucleus and to phosphorylate Cdc25C at serine 216 in vitro. Caffeine does not inhibit Chk2/Cds1 activity directly, but rather, blocks the activation of Chk2/Cds1 by inhibiting ATM kinase activity. In vitro, ATM phosphorylates Chk2/Cds1 at threonine 68 close to the N terminus, and caffeine inhibits this phosphorylation with an IC(50) of approximately 200 microM. Using a phospho-specific antibody against threonine 68, we demonstrate that radiation-induced, ATM-dependent phosphorylation of Chk2/Cds1 at this site is caffeine-sensitive. From these results, we propose a model wherein caffeine abrogates the G(2)/M checkpoint by targeting the ATM-Chk2/Cds1 pathway; by inhibiting ATM, it prevents the serine 216 phosphorylation of Cdc25C in the nucleus. Inhibition of ATM provides a molecular explanation for the increased radiosensitivity of caffeine-treated cells.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
275
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10342-8
pubmed:dateRevised
2011-11-2
pubmed:meshHeading
pubmed-meshheading:10744722-Ataxia Telangiectasia, pubmed-meshheading:10744722-Caffeine, pubmed-meshheading:10744722-Cell Cycle, pubmed-meshheading:10744722-Cell Cycle Proteins, pubmed-meshheading:10744722-Cell Line, pubmed-meshheading:10744722-Cell Nucleus, pubmed-meshheading:10744722-DNA Damage, pubmed-meshheading:10744722-DNA-Binding Proteins, pubmed-meshheading:10744722-G2 Phase, pubmed-meshheading:10744722-Gamma Rays, pubmed-meshheading:10744722-Humans, pubmed-meshheading:10744722-Kinetics, pubmed-meshheading:10744722-Mitosis, pubmed-meshheading:10744722-Mutagenesis, Site-Directed, pubmed-meshheading:10744722-Phosphoserine, pubmed-meshheading:10744722-Protein-Serine-Threonine Kinases, pubmed-meshheading:10744722-Recombinant Proteins, pubmed-meshheading:10744722-Tumor Suppressor Proteins, pubmed-meshheading:10744722-cdc25 Phosphatases
pubmed:year
2000
pubmed:articleTitle
Caffeine abolishes the mammalian G(2)/M DNA damage checkpoint by inhibiting ataxia-telangiectasia-mutated kinase activity.
pubmed:affiliation
Department of Oncology Research, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA. Bing-Bing_S_Zhou@sbphrd.com
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't