Discription：Neuregulin/Heregulin is a family of structurally-related polypeptide growth factors derived from alternatively spliced genes （NRG1, NRG2, NRG3 and NRG4） . To date, there are over 14 soluble and transmembrane proteins derived from the NRG1 gene. Proteolytic processing of the extracellular domain of the transmembrane NRG1 isoforms releases soluble growth factors. HRG1-β1 contains an Ig domain and an EGF-like domain; the latter is necessary for direct binding to receptor tyrosine kinases erb3 and erb4. This binding induces erb3 and erb4 heterodimerization with erb2, stimulating intrinsic kinase activity that leads to tyrosine phosphorylation. NRG1 is necessary for cardiac development, structural maintenance, and functional integrity of the heart. NRG1 and its receptor family ErbB can play a beneficial role in the treatment of chronic heart failure （CHF） by promoting survival of cardiac myocytes, improving sarcomeric structure, balancing Ca2+ homeostasis, and enhancing pumping function. Recombinant Human Heregulinβ-1 is a 7.0kDa polypeptide consisting of only the EGF domain of Heregulinβ-1 （177-237a.a.）
