Neuregulin 1 or NRG1 is one of four proteins in the neuregulin family that act on the EGFR family of receptors. Nrg-1 has been shown to encode more than 14 soluble or transmembrane proteins. The extracellular domain of the transmembrane NRG1 isoforms can be proteolytically cleaved to release soluble growth factors. All NRG1 isoforms contain an EGF-like domain ( alpha – or beta -splice variant that differ in their C-terminal region) that is required for their direct binding to the ErbB3 or ErbB4 receptor tyrosine kinases. NRG1 is a trophic factor that has been implicated in neural development, neurotransmission, and synaptic plasticity. Neuregulin 1 (NRG1) is essential for the development and function of multiple organ systems, and its dysregulation has been linked to diseases such as cancer and schizophrenia. NRG1 is a schizophrenia candidate gene and plays an important role in brain development and neural function.