The hCds1 (Chk2)-FHA domain is essential for a chain of phosphorylation events on hCds1 that is induced by ionizing radiation.
hCds1 (Chk2) is an evolutionarily conserved kinase that functions in DNA damage response and cell cycle checkpoint. The Cds1 family of kinases are activated by a family of large phosphatidylinositol 3-kinase-like kinases. In humans, ataxia telangiectasia-mutated (ATM) and ataxia-telangiectasia and Rad3-related kinases activate hCds1 by phosphorylating Thr(68) . hCds1 and Cds1-related kinases contain the FHA (forkhead-associated) domain, which appears to be important for integrating the DNA damage signal. It is not known how ATM phosphorylation activates hCds1 function and whether the phosphorylation is linked to the FHA. Here, we demonstrate that the hCds1-FHA domain is essential for Thr(68) phosphorylation. Thr(68) phosphorylation, in turn, is required for ionizing radiation-induced autophosphorylation of two amino acid residues in hCds1, Thr(383) and Thr(387). These two amino acid residues, located in the activation loop of hCds1, are conserved in hCds1-related kinases and are essential for hCds1 activity. Thus, the hCds1-FHA domain mediates a chain of phosphorylation events on hCds1, which includes phosphorylation by ATM and hCds1 autophosphorylation, in response to DNA damage.
Lee
C H
CH
Laboratory of Biochemical Genetics, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-1654, USA.
Chung
J H
JH
D000595:Amino Acid Sequence; D064447:Checkpoint Kinase 2; D004249:DNA Damage; D018076:DNA, Complementary / Q000378:metabolism; D004789:Enzyme Activation; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000528:radiation effects; D010957:Plasmids / Q000378:metabolism; D011494:Protein Kinases / Q000737:chemistry*; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D011839:Radiation, Ionizing; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012568:Schizosaccharomyces / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins; D017386:Sequence Homology, Amino Acid; D013912:Threonine / Q000378:metabolism
D064447:Checkpoint Kinase 2; D018076:DNA, Complementary; D005982:Glutathione Transferase; D019869:Phosphatidylinositol 3-Kinases; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D011993:Recombinant Fusion Proteins; D029702:Schizosaccharomyces pombe Proteins; D013912:Threonine; C578634:CHEK2 protein, human; C578636:Cds1 protein, S pombe