Catalytic domain of the yeast Serine/Threonine Kinases, Rad53 and Cds1
STKs catalyze the transfer of the gamma-phosphoryl group from ATP to serine/threonine residues on protein substrates. Rad53 and Cds1 are the checkpoint kinase 2 (Chk2) homologs found in budding and fission yeast, respectively. They play a central role in the cell's response to DNA lesions to prevent genome rearrangements and maintain genome integrity. They are phosphorylated in response to DNA damage and incomplete replication, and are essential for checkpoint control. They help promote DNA repair by stalling the cell cycle prior to mitosis in the presence of DNA damage. The Rad53/Cds1 subfamily is part of a larger superfamily that includes the catalytic domains of other protein STKs, protein tyrosine kinases, RIO kinases, aminoglycoside phosphotransferase, choline kinase, and phosphoinositide 3-kinase.