Neuregulin-1/Heregulin Alpha (EGF Domain), human recombinant (rHuNRG1-A)

Recombinant human Neuregulin-1/Heregulin Alpha (EGF Domain) produced in E. coli is a single, non-glycosylated, polypeptide chain containing 65 amino acids and having a total molecular mass of 7.4 kDa. Neuregulin/Heregulin is a family of structurally related polypeptide growth factors which are stemmed from alternatively spliced genes (NRG1, NRG2, NRG3 and NRG4). Thus far, there are more than 14 soluble and transmembrane proteins derived from the NRG1 gene. Proteolytic processing of the extracellular domain of the transmembrane NRG1 isoforms release soluble growth factors. These isoforms contain the heregulins (HRGs), glial growth factors (GGFs) and sensory and motor neuron-derived factor (SMDF). All these factors have the Ig and EGF-like domain, and are able to bind to ErbB3 and ErbB4 receptor tyrosin kinases. This binding stimulates erb3 and erb4 heterodimerization with erb2, promoting intrinsic kinase activity, which results in tyrosine phosphorylation. NRG1 isoforms act to induce the growth and differentiation of epithelial, neuronal, glial, and other types of cells. The ED50 was determined by the dose-dependent stimulation of the proliferation of human MCF-7 cells is less than 0.5 ng/ml, corresponding to a specific activity of > 2.0 × 106 units/mg.