Involved in DNA repair. Has a probable role in repairing alkylated DNA and may regulate the activity of protein(s) involved in double strand break repair caused by gamma rays. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Belongs to the protein kinase superfamily. CK1 Ser/Thr protein kinase family. Casein kinase I subfamily.