Neuregulin-1 is one of the four known proteins of the Neuregulin family and can be found in many organs including the heart, breast, peripheral and central nervous system. Neuregulin-1 is encoded by a gene located on chromosome 8p13 which produces more than 15 different isoforms of the same protein. All isoforms contain a core EGF domain encoded by exon E130 but other elements of the protein vary. Most NRG1 isoforms are synthesized as transmembrane proproteins which undergo proteolytic cleavage processes.