Neurotrophins family and their receptors. In performing its functions, NGF binds to the receptor with tropomyosin type A kinase activity (TrkA), NT-3 binds to the TrkC receptor, and NT-4/5 and BDNF have TrkB as their receptor. But NT-4/5 binds with low affinity to TrkB, whereas BDNF has high affinity for this receptor. Neurotrophins also have one receptor in common, the low affinity nerve growth factor receptor or the p75 neurotrophin receptor (p75NTR), which regulates the same intracellular pathways. NGF: nerve growth factors; NT-3, 4/5: neurotrophin 3, 4 and 5; BDNF: brain-derived neurothrophic factor.