Growth regulation by transforming growth factor-beta.

Abstract

The name transforming growth factor-ß (TGF-ß) has come to represent a family of highly homologous polypeptides with a wide range of biological activities. The first member of this gene family was identified nearly a decade ago as one of two essential factors, called TGF-α and TGF-ß present in the conditioned medium of a murine sarcoma virus-transformed cell line, which together stimulated the anchorage-independent growth of non-transformed fibroblast cell lines [1]. Several members of the TGF-ß family have since been identified, of which TGF-ßl, ß2, and ß3 are produced by mammalian cells. These three forms of TGF-ß have similar biological activities in the majority of assay systems, though differences in relative potency are sometimes evident. For simplicity, we will use the name TGF-ß to refer to the TGF-ß family as a whole, unless otherwise specified. It should, however, be pointed out that most studies have evaluated only the biological activities of TGF-ßl. Finally, a number of proteins have been identified that exhibit structural similarities to TGF-ß, though with a more distant relationship than the individual TGF-ß isoforms. Together with TGF-ß, they constitute the TGF-ß superfamily. As yet little is known about the effects of these factors on cell proliferation, and they will not be discussed here.KeywordsTransform Growth FactorChicken Chorioallantoic MembraneType Beta Transform Growth FactorMink Lung Epithelial CellChinese Hamster Lung Fibroblast CellThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.