NT-4 also named as NT-5 is a neuronal and epithelial grow factor belongs to the NGF-beta family. The NT-4 precursor is consisted of a 24 a.a. signal peptide, a 56 a.a. propertied and 130 a.a. NT-4. The mature protein has six Cys amino acid residues and has the relative structure with NT-3, BDNF (sharing about 48 % - 52 % sequence identity). Additionally, it shares 91 % and 95 % a.a. sequence identity with mouse and rat NT-4. NT-4 is mainly expressed in prostate and has low level thymus, placenta, and skeletal muscle. It can binding with the LNGFR and trkB receptors and plays a crucial role in the regulation of survival and the maintenance of peripheral sensory sympathetic neurons. Defect of NT-4 may cause primary open angle glaucoma type 1O.