Neuregulin 2，also known as NRG2, DON1 or NTAK, is a protein that in humans is encoded by the NRG2 gene. Neuregulin 2 (NRG2) is a novel member of the neuregulin family of growth and differentiation factors. The NRG2 gene is mapped to 5q31.2. Through interaction with the ErbB family of receptors, NRG2 induces the growth and differentiation of epithelial, neuronal, glial, and other types of cells. The human NRG2 gene contains 12 exons and the mouse Nrg2 gene contains 12 exons and spans about 180 kb. The NRG2 genomic structure is similar to that of neuregulin 1 (NRG1), another member of the neuregulin family of ligands. NRG1 and NRG2 mediate distinct biological processes by acting at different sites in tissues and eliciting different biological responses in cells. In particular, the neuregulin-ERBB signaling pathways play crucial roles in regulating the proliferation and differentiation of Schwann cells, the myelin-forming cells in the peripheral nervous system.