The transforming growth factor β (TGFβ) family members are ubiquitously expressed and control a variety of cellular processes by interacting with at least two types of high affinity cell surface receptors. However, the primary signal transduction mechanism of the receptors is unknown. The ras-encoded 21-kDa GTP binding proteins have recently been shown to mediate the effects of other polypeptide growth factors. Here we show that both TGFβ1 and TGFβ2 (5 ng/ml) result in a rapid (within 6 or 12 min, respectively) stimulation of GTP bound to p21(ras) in TGFβ-sensitive intestinal epithelial cells. Further, the CCL64 epithelial cell line, extremely sensitive to growth inhibition by TGFβ, displayed a concentration-dependent increase in GTP bound to p21(ras) by TGFβ1 and a rapid activation of p21(ras) by TGFβ2. The results provide the first direct evidence for rapid activation of a receptor coupling component for TGFβ in epithelial cells.
|Original language||English (US)|
|Number of pages||3|
|Journal||Journal of Biological Chemistry|
|State||Published - 1992|
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology