The role of C-kinase in the physiological activation of the neutrophil oxidase. Evidence from using pharmacological manipulation of C-kinase activity in intact cells.

The role of C-kinase in the triggering of the neutrophil oxidase by two stimuli (latex beads and the chemotactic peptide fMet-Leu-Phe), representative of endocytotic and exocytotic routes of activation, were investigated by using experimental agents that activate, or inhibit C-kinase, in intact cells. The activation by the phagocytotic stimulus latex beads was mimicked by C-kinase activators giving the same characteristic lag (20-30s), followed by a constant oxygen consumption rate with the same maximum rate and affinity for oxygen (Km approx. 13 microM), competed with activation by PMA (4 beta-phorbol 12-myristate 13-acetate) in a simple common-target manner, and was inhibited by retinal, an inhibitor shown to inhibit activation by PMA. In contrast, activation by chemotactic peptide was not mimicked by C-kinase activation alone, chemotactic peptide inducing biphasic oxygen consumption with a Km for oxygen of the second prolonged phase of 3.9 microM, did not compete with activation by PMA, and was not inhibited by retinal. However, PMA and retinal produced slight enhancements of activation by chemotactic peptide and production of monophasic oxygen consumption. It was concluded that C-kinase activation plays a simple central transducing role in activation of the oxidase by latex beads, but that its role in activation by chemotactic peptide is a part of a more complex set of interactions that involve other Ca2+-activated and non-Ca2+-activated processes.