The Checkpoint Clamp Activates Mec1 Kinase during Initiation of the DNA Damage Checkpoint

Majka, Jerzy; Niedziela-Majka, Anita; Burgers, Peter M.

doi:10.1016/j.molcel.2006.11.027

Cited by 173 publications

(208 citation statements)

References 37 publications

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“…However, the mechanism by which the 9-1-1 complex contributes to this process has remained enigmatic. A recent study shed light on the interplay between the 9-1-1 complex and ATR in S. cerevisiae (Majka et al 2006). Using a reconstituted system of purified proteins, this work showed that the S. cerevisiae 9-1-1 complex (Ddc1, Mec3, and Rad17) directly activated the ATR homolog (Mec3) to phosphorylate multiple substrates, including the kinase Rad53.…”

Section: Resultsmentioning

confidence: 99%

The Rad9–Hus1–Rad1 (9–1–1) clamp activates checkpoint signaling via TopBP1

Delacroix¹,

Wagner²,

Kobayashi³

et al. 2007

Genes Dev.

418

415

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DNA replication stress triggers the activation of Checkpoint Kinase 1 (Chk1) in a pathway that requires the independent chromatin loading of the ATRIP-ATR (ATR-interacting protein/ATM [ataxia-telangiectasia mutated]-Rad3-related kinase) complex and the Rad9-Hus1-Rad1 (9-1-1) clamp. We show that Rad9's role in Chk1 activation is to bind TopBP1, which stimulates ATR-mediated Chk1 phosphorylation via TopBP1's activation domain (AD), a domain that binds and activates ATR. Notably, fusion of the AD to proliferating cell nuclear antigen (PCNA) or histone H2B bypasses the requirement for the 9-1-1 clamp, indicating that the 9-1-1 clamp's primary role in activating Chk1 is to localize the AD to a stalled replication fork.Supplemental material is available at http://www.genesdev.org.

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Section: Resultsmentioning

confidence: 99%

The Rad9–Hus1–Rad1 (9–1–1) clamp activates checkpoint signaling via TopBP1

Delacroix¹,

Wagner²,

Kobayashi³

et al. 2007

Genes Dev.

418

415

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show abstract

“…A recent publication demonstrated that the loading of the 9-1-1 clamp onto DNA can stimulate the phosphorylation of Mec1 substrates in vitro (12). Because Mec1-Ddc2 also associates with DNA (28), the loaded clamp may serve as a scaffold for the recruitment of other Mec1 substrates.…”

Section: Discussionmentioning

confidence: 99%

“…This suggests that Ddc1 and/or a Ddc1-interacting protein may function as a direct activator of Mec1. In fact, Ddc1 purified from yeast has been shown to modestly stimulate the kinase activity of Mec1 in vitro under low-salt conditions (12).…”

mentioning

confidence: 99%

Dpb11 activates the Mec1–Ddc2 complex

Mordes

Nam

Chen

2008

Proc. Natl. Acad. Sci. U.S.A.

112

116

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The Saccharomyces cerevisiae Mec1-Ddc2 checkpoint kinase complex (the ortholog to human ATR-ATRIP) is an essential regulator of genomic integrity. The S. cerevisiae BRCT repeat protein Dpb11 functions in the initiation of both DNA replication and cell cycle checkpoints. Here, we report a genetic and physical interaction between Dpb11 and Mec1-Ddc2. A C-terminal domain of Dpb11 is sufficient to associate with Mec1-Ddc2 and strongly stimulates the kinase activity of Mec1 in a Ddc2-dependent manner. Furthermore, Mec1 phosphorylates Dpb11 and thereby amplifies the stimulating effect of Dpb11 on Mec1-Ddc2 kinase activity. Thus, Dpb11 is a functional ortholog of human TopBP1, and the Mec1/ATR activation mechanism is conserved from yeast to humans.

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“…It is interesting to note that most of them are nuclear proteins involved in DNA replication and repair, DNA damage checkpoint, and RNA metabolism and transcription. Among them, Rpa1 and Mec3 were reported to be directly phosphorylated by Mec1 and/or Tel1 (24,33) and Rad9 was known to undergo a Mec1/Tel1-dependent phosphorylation (34,35). The other targets are previously undescribed findings.…”

Section: Quantitative Proteomic Approach For Comparative Analysis Of mentioning

confidence: 99%

Proteome-wide identification of in vivo targets of DNA damage checkpoint kinases

Smolka

Albuquerque²,

Chen³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

403

434

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Understanding the role of DNA damage checkpoint kinases in the cellular response to genotoxic stress requires the knowledge of their substrates. Here, we report the use of quantitative phosphoproteomics to identify in vivo kinase substrates of the yeast DNA damage checkpoint kinases Mec1, Tel1, and Rad53 (orthologs of human ATR, ATM, and CHK2, respectively). By analyzing 2,689 phosphorylation sites in wild-type and various kinase-null cells, 62 phosphorylation sites from 55 proteins were found to be controlled by the DNA damage checkpoint. Examination of the dependency of each phosphorylation on Mec1 and Tel1 or Rad53, combined with sequence and biochemical analysis, revealed that many of the identified targets are likely direct substrates of these kinases. In addition to several known targets, 50 previously undescribed targets of the DNA damage checkpoint were identified, suggesting that a wide range of cellular processes is likely regulated by Mec1, Tel1, and Rad53. mass spectrometry ͉ Mec1 ͉ N-isotag ͉ phosphorylation ͉ Rad53

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The Checkpoint Clamp Activates Mec1 Kinase during Initiation of the DNA Damage Checkpoint

Cited by 173 publications

References 37 publications

The Rad9–Hus1–Rad1 (9–1–1) clamp activates checkpoint signaling via TopBP1

The Rad9–Hus1–Rad1 (9–1–1) clamp activates checkpoint signaling via TopBP1

Dpb11 activates the Mec1–Ddc2 complex

Proteome-wide identification of in vivo targets of DNA damage checkpoint kinases

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