Promotes the exchange of Ras-bound GDP by GTP (By similarity). Required for cyclic GMP-mediated chemotaxis, polarity. Plays a key role in cyclic AMP-induced myosin II translocation to the cortex. Also involved in the phosphorylation of mlkA and mlcR, either directly or via an intermediate kinase. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Increases dramatically after starvation is initiated with a peak between 4-12 hours. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. ROCO subfamily.