Overexpression of protein kinase C-epsilon enhances the stimulatory effect of ethanol on phospholipase C-mediated hydrolysis of phosphatidylethanolamine in NIH 3T3 fibroblasts.

Previously, ethanol and the protein kinase C (PKC) activators phorbol 12-myristate 13-acetate (PMA) and bombesin were shown to synergistically stimulate phospholipase C (PLC)-mediated hydrolysis of phosphatidylethanolamine (PtdEtn) in NIH 3T3 fibroblasts. Here we used fibroblasts overexpressing PKC-epsilon 15-fold to examine the possible role of this enzyme in the regulation of PtdEtn hydrolysis by ethanol. Overexpressed PKC-epsilon (i) greatly enhanced the stimulatory effects of ethanol (37.5-150 mM) on PLC-mediated PtdEtn hydrolysis, and (ii) eliminated the need for the co-presence of a PKC activator for maximal (3.3-fold) stimulation of PLC by 150 mM ethanol. Results suggest that PKC-epsilon is a potential positive regulator of the PtdEtn-hydrolyzing PLC activity, and that the functional interaction between PKC-epsilon and PLC is facilitated by ethanol.