Recombinant Mouse Epiregulin Protein

Epiregulin is a member of the EGF family of growth factors which includes, among others, epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, amphiregulin (ARG), HB (heparin-binding)-EGF, betacellulin, and the various heregulins. They are all synthesized as transmembrane precursors and converted to soluble forms by proteolytic cleavage. Epiregulin was originally purified from the mouse fibroblast-derived tumor cell line NIH3T3/T7 (1). The mouse Epiregulin cDNA encodes for a transmembrane precursor of 162 amino acid in length, with the mature soluble form comprising residues 56 - 101 (2). The mode of action of Epiregulin is similar to other EGF family members in that it binds to and activates the tyrosine-kinase, ErbB-family receptors (ErbB1 through B4) (3). Although it stimulates phosphorylation of all four receptors, it appears to interact primarily with ErbB1 and ErbB4. Epiregulin has the broadest specificity of the EGF-like ligands but seems to preferentially activate heterodimeric receptor complexes (4). Epiregulin exhibits a variety of biological effects. It was originally shown to both inhibit growth of several epithelial tumor cells and stimulate growth of fibroblasts and other types of cells (1). Epiregulin expression is upregulated in a number of carcinoma cell lines. It has also been shown to be an autocrine growth factor in human epidermal keratinocytes (5). Epiregulin has also been shown to play a role in the early steps of pregnancy, regulating attachment of the blastocyst to the uterine epithelium during the implantation process (6).