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PubMed · 16530042

TopBP1 activates the ATR-ATRIP complex.

Akiko Kumagai·Joon Lee·Hae Yong Yoo·William G Dunphy
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Abstract

ATR is a key regulator of checkpoint responses to incompletely replicated and damaged DNA, but the mechanisms underlying control of its kinase activity are unknown. TopBP1, the vertebrate homolog of yeast Cut5/Dbp11, has dual roles in initiation of DNA replication and regulation of checkpoint responses. We show that recombinant TopBP1 induces a large increase in the kinase activity of both Xenopus and human ATR. The ATR-activating domain resides in a conserved segment of TopBP1 that is distinct from its numerous BRCT repeats. The isolated ATR-activating domain from TopBP1 induces ectopic activation of ATR-dependent signaling in both Xenopus egg extracts and human cells. Furthermore, Xenopus egg extracts containing a version of TopBP1 with an inactivating point mutation in the ATR-activating domain are defective in checkpoint regulation. These studies establish that activation of ATR by TopBP1 is a crucial step in the initiation of ATR-dependent signaling processes.

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Amino Acid SequenceAnimalsAtaxia Telangiectasia Mutated ProteinsCarrier ProteinsCell CycleCell Cycle ProteinsDNA DamageDNA RepairDNA-Binding ProteinsEnzyme ActivationGenes, ReporterHumansMacromolecular SubstancesMolecular Sequence DataNuclear ProteinsOocytesPoint MutationProtein Serine-Threonine KinasesProtein Structure, TertiaryRecombinant ProteinsSequence AlignmentSignal TransductionTumor Suppressor ProteinsXenopus ProteinsXenopus laevisJournal ArticleResearch Support, N.I.H., Extramural

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Akiko Kumagai, Joon Lee, Hae Yong Yoo, William G Dunphy. 2006-03-10. TopBP1 activates the ATR-ATRIP complex.. https://doi.org/10.1016/j.cell.2005.12.041

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