chk1

The protein kinase Chk1 is essential for the DNA damage checkpoint...

ATR/Rad3-like kinases promote the DNA damage checkpoint through regulating Chk1 that restrains the activation of cyclin-dependent kinases...

..The Chk1 kinase, an effector of the DNA-damage checkpoint, phosphorylates Cdc25, an activator of Cdc2...

..We propose that RFC(Ctf18) and the Swi1-Swi3 complex function in separate and redundant pathways essential for replication fork stabilization to facilitate sister chromatid cohesion in fission yeast...

..Caffeine prevented activation of Cds1 and phosphorylation of Chk1, two protein kinases that enforce the S-M checkpoint triggered by hydroxyurea...

..fact, Tel2 is required for survival of replication fork arrest and for the replication checkpoint in cells lacking Chk1, another checkpoint kinase the role of which overlaps that of Cds1 in cell cycle arrest by replication block...

..We propose that Sap1 is required to recruit the FPC to chromatin, thereby contributing to the activation of the replication checkpoint and the stabilization of replication forks...

..Inactivation of Mus81 triggers a checkpoint-dependent delay of mitosis. We propose that Mus81 is involved in the recruitment of Cds1 to aberrant DNA structures where Cds1 modulates the activity of damage tolerance enzymes...

The protein kinase Chk1 is required in the fission yeast Schizosaccharomyces pombe for delaying cell cycle progression in response to DNA damage...

..Moreover, the viability of cdc20(DeltaN-term) cells is dependent on expression of rad3(+), hus1(+), and chk1(+), three genes essential for the DNA damage checkpoint control...

b>Chk1 kinase is activated by phosphorylation at serine-345 by Rad3 checkpoint kinase and is required for DNA damage checkpoint in late S and G2 phase of S. pombe cell cycle...

The conserved protein kinase Chk1 mediates cell cycle progression and consequently the ability of cells to survive when exposed to DNA damaging agents...

..We propose that Swi1 and Swi3 define a fork protection complex that coordinates leading- and lagging-strand synthesis and stabilizes stalled replication forks...

..In Schizosaccharomyces pombe, the Chk1 kinase is essential for mitotic arrest and is phosphorylated after DNA damage...

..Upon UV damage, Crb2 is transiently modified, probably phosphorylated, with a similar timing of phosphorylation in Chk1 kinase, which is reported to restrain Cdc2 activation...

..wee1 is required for cell cycle arrest induced by up-regulation of an essential component of this checkpoint, chk1. We observed that p107wee1 is hyperphosphorylated in cells delayed by chk1 overexpression or UV irradiation, and ..

..of mutants defective in DNA replication elongation, mutants defective in DNA replication initiation require the Chk1 kinase...

..We have called the gene encoding this protein chk1 for checkpoint kinase...

..Swi1 is recruited to chromatin during S phase. We propose that Swi1 stabilizes replication forks in a configuration that is recognized by replication checkpoint sensors...

..The kinase Wee1 and the phosphatase Cdc25, which regulate Cdc2 phosphorylation, were evaluated as targets of Chk1, a kinase essential for the checkpoint...

In the fission yeast Schizosaccharomyces pombe, the protein kinase Chk1 has an essential role in transducing a delay signal to the cell cycle machinery in the presence of DNA damage...

..The arrest depends upon the checkpoint Rad proteins and, surprisingly, the Chk1 protein, which is thought to act only from late S phase...

..From these data we conclude that an evolutionary conserved Mms1-Mms22 complex is required for replication of damaged DNA in fission yeast...

..We propose that Mms22 functions directly at the replication fork to maintain genomic integrity in a pathway involving Mus81-Eme1...

The protein kinase Chk1 is required for cell cycle arrest in response to DNA damage. We have found that the 14-3-3 proteins Rad24 and Rad25 physically interact with Chk1 in fission yeast...

..We propose that coordinated expression of Mrc1 with replication control proteins helps to ensure activation of the appropriate checkpoint response during DNA replication...

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..In fission yeast, checkpoint mechanisms are known to regulate entry into mitosis, but so far no checkpoint inhibiting S phase entry has been identified...

The protein kinase Chk1 is required for proper arrest of the cell cycle in response to DNA damage...

..have additive effects on MMS sensitivity and on the MMS-induced damage checkpoint response when combined with chk1 and cds1, but they are nonadditive with hsk1...

..These results suggest that Ddb1, along with Cullin 4 and the signalosome, constitute a major pathway controlling genome stability, repair, and differentiation via RNR regulation...

..Other genes identified are likely to play general roles in gene expression and protein localization...

..These data suggest that Hsk1-Dfp1/Him1 and Swi1-Swi3 complexes have interrelated roles in stabilization of arrested replication forks...

..We propose a role for Nse5/6 mutants in suppressing recombination that results in Holliday junction formation or in Holliday junction resolution...

The protein kinase Chk1 is an essential component of the DNA damage checkpoint pathway. Chk1 is phosphorylated and activated in the fission yeast Schizosaccharomyces pombe when cells are exposed to agents that damage DNA...

..pombe Pot1 and Rqh1 may be conserved in their respective human counterparts POT1 and WRN...

..We show that these proteins function redundantly in DNA repair. Rfp1 was isolated as a Chk1-interacting protein in a two-hybrid screen and has high amino acid sequence similarity to Rfp2...

..A screen for suppressors of a fission yeast chk1 mutant defective in the checkpoint pathway identified a novel Schizosaccharomyces pombe protein, Msc1...

..of 14-3-3 (beta and zeta isoforms in mammalian cells and Rad24 in fission yeast) bind to Ser345-phosphorylated Chk1 and promote its nuclear retention...

..during the G2 phase of the cell cycle delays mitotic progression through activation of the checkpoint kinase, Chk1. Delay of the cell cycle is believed to be essential to allow time for either replication restart (in S phase) or ..

..Both orp1 and sna41 cells exhibited HU hypersensitivity in the absence of Chk1, a DNA damage checkpoint kinase, and were defective in full activation of Cds1, a replication checkpoint kinase, ..

..Schizosaccharomyces pombe ortholog of human ATR and Saccharomyces cerevisiae Mec1, activates the checkpoint kinase Chk1 in response to DNA double-strand breaks (DSBs)...

..of Mcb1 disrupted the association of Mcm2 with other MCM proteins, resulting in inhibition of DNA replication, DNA damage, and activation of the checkpoint kinase Chk1. Thus, Mcb1 appears to antagonize the function of MCM helicase.

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..We propose that Hst4 is a deacetylase involved in the restoration of chromatin structure following the S phase of cell cycle and DNA damage response...

..following S-phase arrest by cdc20-M10, but not by the DNA synthesis inhibitor hydroxyurea, reminiscent of the chk1 mutant. Unlike chk1 , rad17-d14 was not sensitive to UV irradiation...

..The second class includes chk1(+) and the two Schizosaccharomyces pombe 14-3-3 genes, rad24(+) and rad25(+), which appear to suppress the ..

..One of these sites is the putative leucine zipper, which is conserved in other phosphatidylinositol 3-kinase-related family members. The other is a novel motif, which may also mediate Rad3p protein-protein interactions...

The protein kinase Chk1 enforces the DNA damage checkpoint. This checkpoint delays mitosis until damaged DNA is repaired. Chk1 regulates the activity and localization of Cdc25, the tyrosine phosphatase that activates the cdk Cdc2...

..Thus, the Cds1-mediated intra-S phase checkpoint response induced by hydroxyurea can also be distinguished from the S-M phase checkpoint response that requires the initiation DNA synthesis by Polalpha...

..The spp1 mutant displaying an aberrant mitotic phenotype also fails to properly activate the Chk1 checkpoint kinase, but not the Cds1 checkpoint kinase...

..Genetic analyses show that rhp18 controls a unique DNA damage repair/tolerance pathway that extends beyond the requirement to tolerate damage during S-phase, suggesting a broader definition of the function of this eukaryotic PRR protein...

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..Mcm7p is a nuclear protein throughout the cell cycle, and its localization is dependent on the other MCM proteins. Our data suggest that the Mcm3p-Mcm5p dimer interacts with the Mcm4p-Mcm6p-Mcm7p core complex through Mcm7p...

..Cds1 also inhibited Cdc25-dependent activation of Cdc2 in vitro. Chk1, a protein kinase that is required for the G2-M damage checkpoint that prevents mitosis while DNA is being repaired,..

..The activation mechanism of the DNA damage checkpoint therefore differs between pof3Delta and skp1(ts), implicating a novel role for Skp1 in the checkpoint-signalling cascade...

..It is suggested that cell cycle be positively controlled in an ste9-dependent manner before essential factors for viability and other important functions are exhausted when protein synthesis is inhibited...

..Furthermore, hypersensitivity to treatments that induce DSBs suggests that Taz1p is involved in DSB repair. Our observations imply roles for Taz1p-containing telomeres in preventing and repairing DNA breaks throughout the genome...

..It is hypothesized that the rhp54+ gene is involved in the recombinational repair of UV and X-ray damage and plays a role in the processing of replication-specific lesions...

..We conclude that this novel UBC enzyme plays multiple roles and is virtually essential for cell proliferation...

..We have isolated the S.cerevisiae sequence, which we have named RHC31 ( ad31homologue in S. erevisiae), since we show that it can complement the slow growth phenotype and radiation sensitivity of S.pombe rad31...

Fission yeast p56(chk1) kinase is known to be involved in the DNA damage checkpoint but not to be required for cell cycle arrest following exposure to the DNA replication inhibitor hydroxyurea (HU)...

..A model for how pcn1-3 defects may affect DNA repair and replication is presented...

b>Chk1 is a protein kinase that is the effector molecule in the G2 DNA damage checkpoint...

..A model of how Rad26 monitors S-phase progression to maintain the dependency of cell cycle events and coordinates with other rad/hus checkpoint gene products in responding to radiation damage is proposed...

..In contrast, caffeine has no effect on the DNA replication S phase checkpoint in response to inhibition of DNA synthesis by hydroxyurea...

..Previous studies have shown that Rad3 fulfills its function via the regulation of the Chk1 and Cds1 protein kinases. Here we describe a novel role for Rad3 in the control of telomere integrity...

..In summary, Cdc45p chromatin binding requires an intact pre-replicative complex as well as signaling from both the Dbf4-dependent kinase and cyclin-dependent kinases...

..These results indicate that the Hsk1p kinase is a potential target of Cds1p regulation and that its activity is required after replication initiation for normal mitosis...

..This checkpoint is enforced by Chk1, a protein kinase that inhibits the mitotic inducer Cdc25...

..Here, we analyze mutants in the BRCT domains of fission yeast Crb2, which mediates Chk1 activation, and provide evidence for a novel function of the Chk1 pathway...

..lengths of mutant combinations of various checkpoint-related proteins (Rad1, Rad3, Rad9, Rad17, Rad26, Hus1, Crb2, Chk1, Cds1), Tel1, a telomere-binding protein (Taz1), and DNA repair proteins (Ku70, Rad32), we conclude that Rad3/Rad26 ..

..Our results suggest that fission yeast meiosis is exceptionally tolerant of DNA damage, and that some forms of spontaneous S-phase damage can be repaired by recombination without activating checkpoint arrest...

Activation of the Chk1 protein kinase by DNA damage enforces a checkpoint that maintains Cdc2 in its inactive, tyrosine-15 (Y15) phosphorylated state...

..The checkpoint protein kinase Chk1, required for cell cycle arrest in response to DNA damage, was also isolated in this screen...

..However, these cells still require the checkpoint kinase Chk1 for viability, suggesting an alternative checkpoint is activated...