TrkC

TrkC, encoded by the NTRK3 gene, is the specific receptor for neurotrophin-3 (NT-3) and shows the narrowest ligand specificity of the Trk family. It is essential during development for the survival and differentiation of proprioceptive sensory neurons, which convey limb position information to the central nervous system. Ligand binding activates canonical RAS/MAPK, PI3K/AKT, and PLC-gamma cascades, and naturally occurring kinase-insert isoforms extend the receptor's signaling repertoire beyond the canonical pathway. A hallmark of NTRK3 is the ETV6-NTRK3 fusion transcript, the defining lesion of infantile fibrosarcoma and secretory breast carcinoma, which makes TrkC a validated oncogenic target for TRK inhibitors.