CDC6 interaction with ATR regulates activation of a replication checkpoint in higher eukaryotic cells.
J Cell Sci
; 123(Pt 2): 225-35, 2010 Jan 15.
Article
em En
| MEDLINE
| ID: mdl-20048340
ABSTRACT
CDC6, a replication licensing protein, is partially exported to the cytoplasm in human cells through phosphorylation by Cdk during S phase, but a significant proportion remains in the nucleus. We report here that human CDC6 physically interacts with ATR, a crucial checkpoint kinase, in a manner that is stimulated by phosphorylation by Cdk. CDC6 silencing by siRNAs affected ATR-dependent inhibition of mitotic entry elicited by modest replication stress. Whereas a Cdk-phosphorylation-mimicking CDC6 mutant could rescue the checkpoint defect by CDC6 silencing, a phosphorylation-deficient mutant could not. Furthermore, we found that the CDC6-ATR interaction is conserved in Xenopus. We show that the presence of Xenopus CDC6 during S phase is essential for Xenopus ATR to bind to chromatin in response to replication inhibition. In addition, when human CDC6 amino acid fragment 180-220, which can bind to both human and Xenopus ATR, was added to Xenopus egg extracts after assembly of the pre-replication complex, Xenopus Chk1 phosphorylation was significantly reduced without lowering replication, probably through a sequestration of CDC6-mediated ATR-chromatin interaction. Thus, CDC6 might regulate replication-checkpoint activation through the interaction with ATR in higher eukaryotic cells.
Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Xenopus
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Proteínas Nucleares
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Proteínas Cromossômicas não Histona
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Proteínas Serina-Treonina Quinases
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Proteínas de Ciclo Celular
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Proteínas de Xenopus
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Replicação do DNA
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Células Eucarióticas
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article