NT-3 is a neurotrophic factor structurally related to β-NGF, BDNF, and NT-4. These proteins belong to the cysteine-knot family of growth factors that assume stable dimeric structures. NT-3 is expressed by neurons of the central nervous systems, and can signal through the trk receptors. NT-3 promotes the growth and survival of nerve and glial cells. The amino acid sequences of human, murine and rat NT-3 are identical. Recombinant Human NT-3 is a noncovalently linked homodimer of two 13.6 kDa polypeptide monomers (240 total amino acid residues).