Protein Kinase C of Intestinal Epithelium: Its Role in the Control of Ionic Transport
Protein kinase C activity has been identified in rat and rabbit small intestine epithelial cells. When the crude cytosolic fraction was assayed, a Ca activated protein kinase activity which was independent of any exogenously added phospholipid was identified. Protein kinase C activity was resolved from other protein kinase activities by ion exchange chromatography. Phosphatidylserine was required for protein kinase C to be active. The activation of protein kinase C was a function of phosphatidylserine concentrations up to 50 μg/ml. In the presence of phosphatidylserine and diolein, the Ka for activation by Ca was 10-7 M. The phorbol ester TPA, used at 1–5 ng/ml concentrations, substituted for diacylglycerol in activating protein kinase C. The results are dicussed within a body of evidence which indicates that protein kinase C is implicated in the control of the ionic transport in the intestinal epithelium.
KeywordsProtein Kinase Ionic Transport Intestinal Epithelium Cytosolic Fraction DEAE Cellulose
protein kinase C
inositol 1,4,5 trisphosphate
ethylene glycol bid (β-aminoethylether)-N,N,N′ N′ tetraacetic acid
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