Evidence: FceRI stimulation induced a reduced production of IL-6 mRNA and protein in PKCb -/- mast cells (14), which is consistent with an increased accumulation of IL-6 mRNA in PKCb-overexpressing mast cells (15). Since PKCb (and PKCe) can be involved in FceRI-induced expression of c-fos and c-jun mRNAs (16), reduced induction of JunD mRNA may contribute to the reduced IL-6 production in PKCb -/- mast cells.