Inositol lipids and phosphatidic acid inhibit cell-free activation of neutrophil NADPH oxidase

The effect of inositol lipids on the SDS-initiated cell-free activation of NADPH oxidase in membranes of human neutrophils was investigated. In a system consisting of low density membranes, cytosol and SDS, low doses of phosphatidylinositol, phosphatidylinositol mono- and biphosphates and phosphatidic acid interfered with activation of the oxidase. The inhibition was relieved by increasing concentrations of the cytosol. Conversely, preincubation of multilamellar phosphoinositide vesicles with cytosol reduced its ability to support activation of the oxidase.