Serine/threonine-protein kinase which positively regulates Ras-mediated signaling probably acting at the level of let-60/ras or/and lin-45/raf. Involved in sex myoblast migration (PubMed:8521513, PubMed:11882296). Plays a role in responses to M.nematophilum-mediated bacterial infection by promoting tail swelling and preventing constipation (PubMed:15268855). Functions redundantly with ksr-2 in the Ras-mediated regulation of larval survival, the development of excretory canal and in mpk-1 phosphorylation in somatic cells (PubMed:8521513, PubMed:11882296). In addition, involved in determining vulval precursor cell fate during vulval induction independently of its kinase activity (PubMed:8521514, PubMed:8521513, PubMed:10409742, PubMed:11882296). Plays a role in egg-laying (PubMed:23900546). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with mek-2. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. The kinase may be catalytically inactive.