PROTEINKINASE-C BETA-ISOFORM TRIGGERS THE FORMATION OF PROSTANOIDS AND SUPEROXIDE IN LIVER MACROPHAGES

The zymosan- and phorbolester-induced formation of prostanoids in cultured rat liver macrophages has been shown recently to be controlled by proteinkinase C (1). Using specific antibodies raised against the α-, β-, γ- and ε-isoforms of proteinkinase C, we show that proteinkinase-β is the predominant isoform in rat liver macrophages. Northern blot analysis with a β-isoform-specific c-DNA probe revealed the expression of m-RNA for proteinkinase-β. In resting cells the β-isoform of proteinkinase C is nearly equally distributed between the cytosolic and membrane fractions. Zymosan and phorbolester led to a translocation of proteinkinase-β from the cytosol to the membranes, whereas exogenously added arachidonic acid and the calcium ionophore A23187 had no effect. These data indicate that the β-isoform of proteinkinase C takes part in the prostaglandin and superoxide formation following PMA and zymosan treatment of rat liver macrophages. © 1992 Academic Press, Inc.