PANTHER family review PTHR43895: IBA propagation assessment for chk1
Gene Ontology annotation through association of InterPro records with GO terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Automatic Gene Ontology annotation based on Rhea mapping
Combined Automated Annotation using Multiple IEA Methods
Mechanism of caffeine-induced checkpoint override in fission yeast.
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Caffeine inhibits Rad3, blocking phosphorylation of Chk1 and activation of Cds1, thereby overriding both the S-M replication and G2-M DNA damage checkpoints. Chk1 is regulated by Rad3.
"Caffeine prevented activation of Cds1 and phosphorylation of Chk1, two protein kinases that enforce the S-M checkpoint triggered by hydroxyurea. Caffeine did not inhibit these kinases in vitro but did inhibit Rad3, a kinase that regulates Cds1 and Chk1."
Serine-345 is required for Rad3-dependent phosphorylation and function of checkpoint kinase Chk1 in fission yeast.
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Rad3 phosphorylates Chk1 on Ser-345; this modification is required for the G2-M DNA damage checkpoint and for survival of DNA damage.
"Rad3 and ATM phosphorylate serine-345 of fission yeast Chk1. Mutation of serine-345 (chk1-S345A) abrogates Rad3-dependent phosphorylation of Chk1 in vivo. The chk1-S345A cells are sensitive to DNA damage and are checkpoint defective."
A novel chk1-dependent G1/M checkpoint in fission yeast.
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Chk1 is required for a G1-phase checkpoint arrest in pre-replicative complex (orp1-4) mutant cells, acting to induce/maintain inhibitory Cdc2 phosphorylation.
"The arrest depends upon the checkpoint Rad proteins and, surprisingly, the Chk1 protein, which is thought to act only from late S phase."
Regulation of checkpoint kinases through dynamic interaction with Crb2.
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Crb2 dynamically interacts with both Rad3 and Chk1; Chk1 activation in vitro requires the Crb2 BRCT domain.
"Crb2 regulates DNA damage checkpoint through temporal and dynamic interactions with Rad3, Chk1 and replication factor Cut5."
Homo-oligomerization is the essential function of the tandem BRCT domains in the checkpoint protein Crb2.
ORFeome cloning and global analysis of protein localization in the fission yeast Schizosaccharomyces pombe.
Fission yeast Rnf4 homologs are required for DNA repair.
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Rfp1 (an Rnf4/RING-finger homolog) was isolated as a Chk1-interacting protein in a two-hybrid screen; rfp1/rfp2 act in DNA repair but checkpoint signaling to Chk1 is normal in their absence.
"Rfp1 was isolated as a Chk1-interacting protein in a two-hybrid screen and has high amino acid sequence similarity to Rfp2."
Phosphorylation-dependent interactions between Crb2 and Chk1 are essential for DNA damage checkpoint.
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Crb2 recruits Chk1 to double-strand breaks via a direct phospho-dependent interaction; Chk1 forms nuclear foci at DSBs that colocalize with Crb2/Rad22.
"Crb2 recruits Chk1 to double-strand breaks (DSBs) through a direct physical interaction."
The DNA damage and the DNA replication checkpoints converge at the MBF transcription factor.
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Upon DNA damage Chk1 phosphorylates the MBF core subunit Cdc10, releasing MBF from chromatin and repressing S-phase gene transcription.
"Chk1 is activated and phosphorylates Cdc10 at its carboxy-terminal domain. This modification is responsible for the repression of MBF-dependent transcription through induced release of MBF from chromatin."
Tolerance of deregulated G1/S transcription depends on critical G1/S regulon genes to prevent catastrophic genome instability.
Two Distinct Cdc2 Pools Regulate Cell Cycle Progression and the DNA Damage Response in the Fission Yeast S.pombe.
The telomere bouquet facilitates meiotic prophase progression and exit in fission yeast.
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Persistent meiotic recombination DNA damage activates the Rad3-Chk1 checkpoint to extend the telomere bouquet/meiotic prophase stage.
"Persistent DNA damages, induced during meiotic recombination, activate the Rad3 and Chk1 DNA damage checkpoint kinases and extend the bouquet stage beyond the chromosome oscillation period."
Fission yeast chk1 protein kinase links the rad checkpoint pathway to cdc2.
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chk1 encodes a protein kinase required for cell-cycle arrest in response to DNA damage or unligated DNA, linking the rad checkpoint pathway to cdc2.
"we have identified a novel fission yeast protein kinase homologue which is involved in cell-cycle arrest when DNA damage has occurred or when unligated DNA is present. We have called the gene encoding this protein chk1 for checkpoint kinase."
Chk1 is a wee1 kinase in the G2 DNA damage checkpoint inhibiting cdc2 by Y15 phosphorylation.
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Chk1 directly phosphorylates Wee1 in vitro and in vivo, maintaining inhibitory Cdc2-Y15 phosphorylation and G2 delay.
"p56chk1 can phosphorylate p107wee1 directly in vitro. These observations suggest that in response to DNA damage p107wee1 is phosphorylated by p56chk1 in vivo, and this results in maintenance of Y15 phosphorylation and hence G2 delay."
Cdc2 tyrosine phosphorylation is required for the DNA damage checkpoint in fission yeast.
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The G2 DNA damage checkpoint arrest depends on inhibitory Cdc2 tyrosine-15 phosphorylation carried out by Wee1 and Mik1.
"the G2 DNA damage checkpoint arrest in S. pombe depends on the inhibitory tyrosine phosphorylation of Cdc2 carried out by the Wee1 and Mik1 kinases."
Cdc25 mitotic inducer targeted by chk1 DNA damage checkpoint kinase.
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Chk1 binds and phosphorylates Cdc25, identifying Cdc25 (not Wee1) as the target of the DNA damage checkpoint that prevents mitotic entry.
"Cdc25 associated with Chk1 in vivo and was phosphorylated when copurified in Chk1 complexes. These findings identify Cdc25, but not Wee1, as a target of the DNA damage checkpoint."
Replication checkpoint requires phosphorylation of the phosphatase Cdc25 by Cds1 or Chk1.
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Chk1 and Cds1 act redundantly at the replication checkpoint, both phosphorylating Cdc25 on the same residues to promote 14-3-3 binding and prevent Cdc2 activation.
"Chk1 functions redundantly with the kinase Cds1 at the replication checkpoint and that both kinases phosphorylate Cdc25 on the same sites, which include serine residues at positions 99, 192 and 359."
Phosphorylation of Wee1 kinase by Chk1