Regulation of growth factor receptors on rat intestinal epithelial (RIE-1) cells by protein kinase C.
The regulation of growth factor receptors by protein kinase C was investigated in rat intestinal epithelial (RIE-1) cells. Short-term treatment of the cells with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate, was employed to activate the kinase and longer-term exposure to the agent was used to assess the effects of protein kinase C depletion. Phorbol ester concentrations as low as 30 nM were found to down-regulate immunoreactive protein kinase C over 6 h, which correlated with the rapid loss of functional kinase activity. Whereas protein kinase C reduced the binding of 125I-labelled EGF, it increased the binding of 125I-labelled angiotensin II to RIE-1 cells. However, the kinase simultaneously inhibited the activation by angiotensin receptors of phosphatidylinositol 4,5 bisphosphate hydrolysis.
Department of Clinical Biochemistry, Addenbrooke's Hospital, Cambridge, UK.
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D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000378:metabolism; D004848:Epithelium / Q000201:enzymology / Q000502:physiology / Q000648:ultrastructure; D066246:ErbB Receptors / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D006868:Hydrolysis; D007422:Intestines / Q000201:enzymology* / Q000502:physiology / Q000648:ultrastructure*; D007457:Iodine Radioisotopes; D007700:Kinetics; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D017978:Receptors, Growth Factor / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007457:Iodine Radioisotopes; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D011945:Receptors, Angiotensin; D017978:Receptors, Growth Factor; D000804:Angiotensin II; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate