Implicated in the relay of the cAMP chemotactic signal and cell differentiation. Important for receptor-mediated activation of adenylyl cyclase. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Activated by tyrosine and threonine phosphorylation. The TXY motif contains the threonine and tyrosine residues whose phosphorylation activates the MAP kinases. Dually phosphorylated on Thr-176 and Tyr-178, which activates the enzyme. Cells, starved for 8 hours, exhibited a decrease in motility and a severe chemotaxis defect toward a cAMP gradient. Aberrancy in chemotaxis was aggravated in the presence of a strong cAMP gradient. Cells also display defective cytoskeletal remodeling in response to chemoattractant stimulation. Cells are defective in aggregation and display multiple crown-like membranous protrusions, which were enriched not only in F-actin but also in myosin II. This aberrant structure, which was proposed to be less stable and unable to provide necessary traction force for cells to move, is believed to be the reason why cells are less motile than wild-type cells. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MAP kinase subfamily.