WORTMANNIN AND 1-BUTANOL BLOCK ACTIVATION OF A NOVEL FAMILY OF PROTEIN-KINASES IN NEUTROPHILS

Neutrophils contain four uncharacterized protein kinases with molecula r masses of ca. 69, 63, 49 and 40 kDa that are rapidly activated upon stimulation of these cells with the chemoattractant fMet-Leu-Phe [Ding , J. and Badwey, J.A. (1993) J. Biol. Chem. 268, 17326-17333]. We now report that wortmannin and 1-butanol block activation of all four of t hese kinases. These reagents are known to inhibit superoxide generatio n in neutrophils stimulated with this agonist. Wortmannin inhibits pho sphatidylinositol 3-kinase and blocks activation of phospholipase D, w hereas 1-butanol can reduce the generation of phosphatidate in cells b y serving as a substrate for phospholipase D. These data suggest that phosphatidylinositol 3-kinase and phospholipase D may be involved in t he activation of several novel protein kinases in neutrophils and that one or more of these kinases is/are involved in superoxide release.