Does not have an essential role in development. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Expressed in embryonic mesoderm, and the optic lamina, wing disk and leg disks of third instar larvae. More abundant in adult head than adult body. Expressed throughout development. Belongs to the protein kinase superfamily. AGC Ser/Thr protein kinase family. cAMP subfamily.