Neurotrophin-3 (NT-3) is a member of the NGF family of neurotrophic factors and is structurally related to β-NGF, BDNF and NT-4. The NT3 cDNA encodes a 257 amino acid residue precursor protein with a signal peptide and a proprotein that are cleaved to yield the 119 amino acid residue mature NT3.The amino acid sequences of mature human, murine and rat NT-3 are identical. NT-3 selectively promotes the differentiation and survival of specific neuronal subpopulations in both the central as well as the peripheral nervous systems.