Regulates cell integrity and functions coordinately with the protein kinase C pathway (pck1 and pck2). Involved the regulation of wall architecture, cell shape, cytokinesis in exponential and stationary phase, and metabolism of ions. 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 by skh1/pek1. The TXY motif contains the threonine and tyrosine residues whose phosphorylation activates the MAP kinases. Dually phosphorylated on Thr-186 and Tyr-188, which activates the enzyme. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MAP kinase subfamily.