Serine/threonine-protein kinase that acts as a key regulator of NRAS signaling by mediating phosphorylation of NRAS at 'Ser-89', thereby enhancing NRAS-binding to its downstream effectors. ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Divalent metal cations. Has a preference for Mn(2+). Interacts (via N-terminus) with BAG1. Belongs to the STK19 family.