Enables protein homodimerization activity and protein serine/threonine kinase activity. Involved in JNK cascade; positive regulation of JUN kinase activity; and protein phosphorylation. Acts upstream of or within negative regulation of motor neuron apoptotic process. Located in cytosol; growth cone; and plasma membrane. Is expressed in several structures, including alimentary system; genitourinary system; integumental system; nervous system; and sensory organ. Orthologous to human MAP3K12 (mitogen-activated protein kinase kinase kinase 12). [provided by Alliance of Genome Resources, Apr 2022]