Transducer of the DNA damage signal. Phosphorylates SML1 on serine residues. Cooperates with the PAN deadenylation complex in the regulation of RAD5 mRNA levels and cell survival in response to replicational stress. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with the PAB-dependent poly(A)-nuclease (PAN) complex regulatory subunit PAN3 via its forkhead-associated (FHA) domain. Autophosphorylation increases in response to DNA damage. Present with 3480 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. CHEK2 subfamily.