Receptor tyrosine kinase involved in nervous system and probably heart development. Upon binding of its ligand NTF3/neurotrophin-3, NTRK3 autophosphorylates and activates different signaling pathways, including the phosphatidylinositol 3-kinase/AKT and the MAPK pathways, that control cell survival and differentiation (By similarity). NTRK3 isoforms containing insertions within the kinase domain can autophosphorylate in response to NTF3/neurotrophin-3, but cannot mediate downstream phenotypic responses (PubMed:8494647, PubMed:8494648). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Exists in a dynamic equilibrium between monomeric (low affinity) and dimeric (high affinity) structures (By similarity). Binds SH2B2 (PubMed:9856458). Interacts with SQSTM1 and KIDINS220 (PubMed:12471037, PubMed:15167895). Interacts with PTPRS (PubMed:17967490). Interacts with MAPK8IP3/JIP3 (PubMed:21775604). Additional isoforms seem to exist. Widely expressed, mainly in the nervous tissue. Ligand-mediated auto-phosphorylation. Belongs to the protein kinase superfamily. Tyr protein kinase family. Insulin receptor subfamily.