NT-4 is a neurotrophic factor structurally related to beta-NGF, BDNF, and NT-3. These proteins belong to the cysteine-knot family of growth factors that assume stable dimeric structures. NT-4 is expressed in the prostate, thymus, placenta, and skeletal muscle. NT-4 can signal through the LNGFR and trkB receptors, and promotes the survival of peripheral sensory sympathetic neurons. Recombinant Human NT-4 is a noncovalently linked homodimer of two 14.0 kDa polypeptide monomers (260 total amino acid residues).