ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Preferentially expressed in striated muscle. May be autophosphorylated. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.