Description
NTRK2 (Neurotrophic Tyrosine Kinase, Receptor, type 2), also known as TrkB (Tropomyosin related kinase B), is one of the members of the neurotrophin receptor family, which include TrkA and TrkC. All three Trk proteins exhibit a conserved subdomain that contains a signal peptide, two cysteine rich domains, a cluster of three leucine rich motifs, and two Ig-like domains in the extracellular portion. It has been shown that Trk receptor-mediated neurotrophic signaling regulates neuron physiology, cell proliferation and survival, axon and dendrite growth and patterning, and synaptic plasticity. The neurotrophins that activate NTRK2 are BDNF (Brain Derived Neurotrophic Factor), Neurotrophin-3 (NT-3), and Neurotrophin-4 (NT-4). BDNF is known to trigger NTRK2 dimerization and auto phosphorylation that leads to the activation of downstream signaling pathways. After the receptor-ligand binding, NTRK2-BDNF complex is internalized and transported from the nerve terminal to the cell body as signaling endosomes to mediate numerous signaling events. It has been demonstrated that activation of NTRK2 can lead to the down regulation of the main potassium-chloride cotransporter KCC2 in neurons, thereby increasing the intracellular Cl - concentration in lamina I neurons. Recently, it was shown that BDNF-NTRK2 signaling may play a role in the pathogenesis of post-traumatic stress disorders and mutations in the NTRK2 gene have been associated with obesity and mood disorders.
