Serine/threonine protein kinase (PubMed:19450734, PubMed:27002830). May phosphorylate ZC3H11 during unstressed conditions, leading to proteasome-dependent degradation of ZC3H11 (PubMed:27002830). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Optimum temperature is about 27 degrees Celsius. Loses activity at 41 degrees Celsius. RNAi-mediated knockdown in the bloodstream form inhibits cell population growth and leads to gross morphological changes and multinucleation (PubMed:19450734). RNAi-mediated knockdown in the procyclic form inhibits cell population growth and decreases ZC3H11 phosphorylation (PubMed:27002830). Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.