Protein kinases C-β and C-ε link the mast cell high-affinity receptor for IgE to the expression of c-fos and c-jun

In this report we identify the specific isozymes of protein kinase C (PKC) that are involved in c-fos and c-jun mRNA accumulation in the rat basophilic leukemia cell line RBL-2H3. These cells could be largely depleted of the endogenous PKC isozymes by chronic treatment with phorbol 12-myristate 13- acetate followed by permeabilization of the cells with streptolysin O. The reconstitution of these cells with defined concentrations of either PKC-β or PKC-ε up to 10 nM and 20 nM, respectively, induced c-fos and c-jun in a dose-dependent manner. At high concentrations of PKC-β and -ε the induction of c-fos and c-jun was independent of the aggregation of the high-affinity IgE receptors (Fc(ε) type I receptors). In contrast, at limiting concentrations of these two PKC isozymes, 1 nM, the increase in c-fos and c- jun mRNAs was dependent on the aggregation of the Fc(ε) type I receptors. Unlike PKC-β and -ε, PKC-α and PKC-δ failed to reconstitute c-fos and c- jun induction at any dose over the range examined. We conclude that PKC-β and PKC-ε serve as a link between the cell surface receptor and gene expression.