title: Substrate specificity determinants of the checkpoint protein kinase Chk1.
abstract: The Chk1 protein kinase plays a critical role in a DNA damage checkpoint pathway conserved between fission yeast and animals. We have developed a quantitative assay for Chk1 activity, using a peptide derived from a region of Xenopus Cdc25C containing Ser-287, a known target of Chk1. Variants of this peptide were used to determine the residues involved in substrate recognition by Chk1, revealing the phosphorylation motif Phi-X-beta-X-X-(S/T)*, where * indicates the phosphorylated residue, Phi is a hydrophobic residue (M>I>L>V), beta is a basic residue (R>K) and X is any amino acid. This motif suggests that Chk1 is a member of a group of stress-response protein kinases which phosphorylate target proteins with related specificities.
authors.affiliation: Biomedical Research Centre, University of Dundee, Level 5, Ninewells Hospital and Medical School, Dundee, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Hutchins
authors.forename: M
authors.initials: M
authors.lastname: Hughes
authors.forename: P R
authors.initials: PR
authors.lastname: Clarke
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D020134:Catalytic Domain / Q000235:genetics; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D004249:DNA Damage; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D013379:Substrate Specificity; D014981:Xenopus; D029867:Xenopus Proteins; D020687:cdc25 Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D029867:Xenopus Proteins; D012694:Serine; D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; C000605875:Chek1 protein, Xenopus; C517009:CDC25C protein, human; D020687:cdc25 Phosphatases