title: Biologically active precursor for transforming growth factor type alpha, released by retrovirally transformed cells.
abstract: Retrovirus-transformed rat cells that actively express transforming growth factor type alpha (TGF-alpha) release into the medium a soluble protein of 17-19 kDa that has been identified as a precursor for TGF-alpha. The identification of this protein as a TGF-alpha precursor is based on its recognition by specific antibodies and by the ability of elastase to convert this protein into a 6-kDa polypeptide with the properties of mature TGF-alpha. This TGF-alpha precursor binds to epidermal growth factor/TGF-alpha receptors and activates the receptor-associated tyrosine kinase activity in intact cells. The biological potency of this precursor is not markedly increased by conversion into mature TGF-alpha in vitro. These studies demonstrate the ability of transformed cells to release a TGF-alpha precursor capable of strong mitogenic action in vivo.
mesh_terms: D000818:Animals; D002460:Cell Line; D002472:Cell Transformation, Viral; D003470:Culture Media; D066246:ErbB Receptors; D010196:Pancreatic Elastase / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism; D012995:Solubility; D015291:Transforming Growth Factors
chemical_list: D003470:Culture Media; D010455:Peptides; D011498:Protein Precursors; D011956:Receptors, Cell Surface; D015291:Transforming Growth Factors; D066246:ErbB Receptors; D010196:Pancreatic Elastase