ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Weakly expressed in vegetative cells. Expression increases during development until culmination. Higher levels detected during aggregation and culmination. Enriched in prespore cells. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family.