May be involved in some stage-specific role in the promastigote cell cycle. [DNA-directed RNA polymerase] + ATP = ADP + H(+) + phospho-[DNA-directed RNA polymerase] Phosphorylation at Thr-15 or Tyr-16 inactivates the enzyme, while phosphorylation at Thr-160 activates it. Forms a stable but non-covalent complex with a regulatory subunit and with a cyclin. Expressed in all life cycle stages, promastigote, metacyclic and amastigote forms but is found in the active form only in the promastigote stage. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. CDC2/CDKX subfamily.