May act on PRP20. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Phosphorylated by PKA in a TORC1-dependent manner. Phosphorylation at PKA consensus sites RRxS/T decreases upon rapamycin treatment. Present with 1270 molecules/cell in log phase SD medium. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family. CK2 subfamily.