The PKC-inhibitor Ro 31-8220 selectively suppresses PMA- and diacylglycerol-induced fluid pinocytosis and actin polymerization in PMNs.

The PKC-inhibitor Ro 31-8220 inhibits stimulated fluid pinocytosis of human PMNs induced by the PKC-activators phorbol myristate acetate (PMA, IC50 = 1.35 x 10(-6) M) or diacylglycerols (OAG, diC8) by 95%, whereas Ro 31-8220 has no effect on D2O- or fNLPNTL-induced pinocytosis and enhances cytochalasin D- induced pinocytosis. Also formation of F-actin induced by PMA or diacylglycerols is selectively inhibited. The results indicate that a Ro 31-8220 -sensitive PKC is involved in signal transduction for enhanced pinocytosis and F-actin formation in response to one class of stimuli (classical activators of PKC) but not to others.