Appearance of basic fibroblast growth factor receptors upon differentiation of rat mammary epithelial to myoepithelial-like cells in culture

✍ Scribed by David G. Fernig; John A. Smith; Philip S. Rudland

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 815 KB
• Volume: 142
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041420114

✦ Synopsis

Abstract

The binding of [^125^I]‐epidermal growth factor (EGF) and [^125^I]‐basic fibroblast growth factor (bFGF) to a number of single‐cell cloned rat mammary cell lines was measured using a saturation assay. Similar numbers of high‐affinity [^125^I]‐EGF binding sites (K~D~ 1.3 nM) were found in epithelial and myoepithelial‐like cell lines. In contrast, high‐affinity (K~D~ 35–276 pM) [^125^I]‐bFGF binding sites were present on fibroblastic and myoepithelial‐like cell lines but were not detectable on epithelial cell lines. A series of cell lines representing stages in the differentiation pathway of epithelial cells to an elongated myoepithelial‐like morphology showed a graded increase in the number of bFGF receptors. The sensitivity of a cell line to stimulation of DNA synthesis by bFGF correlated with the level of expression of bFGF receptors on the cellular surface. Complexes of cell surface receptors affinity‐cross‐linked to [^125^I]‐bFGF were analysed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). In each case two distinct complexes having apparent molecular weights of 180 kDa and 160 kDa were observed.