Serine/threonine-protein kinase which is involved in maintaining synapse and axon morphology as well as touch neuron axon regeneration after injury by regulating cebp-1 mRNA stability downstream of the dlk-1, mkk-4 and pmk-3 signaling cascade (PubMed:19737525). May play a role in body wall muscle contraction (PubMed:19737525). Plays a role in the formation of muscle connections, also called muscle arm extensions, between the body wall and the motor axons in the dorsal and ventral cord (PubMed:27123983). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] Interacts with pmk-3. Colocalizes with snb-1 and partially with cebp-1 at synapses. Expressed in pharynx, intestine and body wall muscles (PubMed:25851606). Expressed in the nervous system (PubMed:19737525). May be phosphorylated at Thr-173 and Thr-285 by pmk-3. Weak defect in the extension of body wall muscle connections or arms towards the ventral nerve cord. Double knockout with madd-3 suppresses the muscle arm extension defects, eva-1 expression defects and restores the defect in the recruitment of madd-4 to the muscle membrane in the madd-3 single knockout. Triple knockout with madd-3 and unc-54 results in paralysis (as in the unc-54 single knockout), and suppresses the lethality phenotype in the double madd-3 and unc-54 mutant. Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family.