Together with the serine/threonine kinase Pkn1, may play a role in the specific interactions with host proteins during intracellular growth. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Autophosphorylated on serine and threonine residues. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.