Tyrosine-protein kinase receptor which, together with ddr-1, is involved in axon guidance to establish the tracts for the ventral and dorsal nerve cords during nervous system development (PubMed:23147028). Acts upstream of the adapter shc-1, and the tyrosine kinase receptors svh-1 and svh-2 to regulate axon regeneration following injury in D-type motor neurons (PubMed:27984580, PubMed:31371405). May mediate axon regeneration in association with the collagen emb-9 (PubMed:27984580). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Interacts with shc-1. Expressed in some neurons in head and tail, some motoneurons in ventral nerve cord, in PVP interneurons, seam cells, rectal gland cells, vulva cells and some non-neuronal cells in the tail (PubMed:23147028). Expressed in D-type motor neurons (PubMed:27984580). Expression begins during late gastrulation in seam cells and in few head neurons. Autophosphorylated on tyrosine residues. N-glycosylation at Asn-141 is required for axon regeneration after injury but is dispensable for kinase activity and axon localization. Viable. Normal morphology of D-type motor neurons, but 24 hours following injury of D-type motor neurons there is reduced axon regeneration. Double knockout with ddr-1 results in a more enhanced axon regeneration defect of D-type motor neurons as compared to the svh-4 and ddr-1 single mutants. Belongs to the protein kinase superfamily. Tyr protein kinase family. Insulin receptor subfamily.