Effect of transforming growth factor-alpha on inositol phospholipid metabolism in human epidermoid carcinoma cells |
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Authors: | M Kato T Takenawa D R Twardzik |
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Affiliation: | Department of Pharmacology, Tokyo Metropolitan Institute of Gerontology, Japan. |
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Abstract: | Transforming growth factor-alpha (TGF-alpha) stimulates (in a dose-dependent manner) the incorporation of [32P]Pi into phosphatidylinositol (PI), phosphatidylinositol 4-phosphate (PIP), phosphatidylinositol 4,5-bisphosphate (PIP2), and phosphatidic acid (PA) in the human epidermoid carcinoma cell line (A431). The effect of TGF-alpha on the incorporation was found to be similar to that of EGF. On the other hand, a striking difference in the activation of diacylglycerol (DG) kinase activity was seen between TGF-alpha and EGF. At least 100 times more TGF-alpha was required to achieve maximal stimulation of DG kinase activity relative to EGF. These results suggest that the activation of DG kinase by TGF-alpha may involve a mechanism independent from or subsequent to activation of the EGF receptor. |
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Keywords: | diacylglycerol kinase activity signal transduction epidermal growth factor |
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