Serine/threonine-protein kinase involved in the SLT2 mitogen-activated (MAP) kinase signaling pathway that regulates cell wall integrity. May also be involved in the mating pheromone and the CWI MAPK pathways. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with RLM1. Accumulates in large amounts when cell wall integrity is compromised. Belongs to the protein kinase superfamily. Ser/Thr protein kinase family.