NEUTROPHIL CHEMOTAXIS INDUCED BY THE DIACYLGLYCEROL KINASE INHIBITOR R59022

The diacylglycerol kinase inhibitor R59022 induced chemotaxis in neutrophils. The response to R59022 was primarily chemotactic and only very little chemokinetic. Pretreatment with the protein kinase C inhibitors staurosporine and AMG-C-16 inhibited chemotaxis induced by R59022 indicating the involvement of protein kinase C. In contrast, chemotaxis induced by fMet-Leu-Phe was only slightly inhibited by staurosporine and AMG16. The effects of R59022 were comparable to the effects of the protein kinase C activators DiC8 and PMA and suggest an involvement of protein kinase C. Pretreatment with pertussis toxin inhibited R59022-induced migration, fMet-Leu-Phe-induced migration, and random migration. GTPgammaS, which stimulates migration of electropermeabilized neutrophils by itself, causes an additive increase of migration in electropermeabilized neutrophils stimulated with a suboptimal concentration R59022, but causes a synergistic increase of migration in cells stimulated with a suboptimal concentration fMet-Leu-Phe. The effects of GTPgammaS on migration are completely inhibited by AMG-C-16. This suggests that the GTP-binding protein involved in R59022-activated migration is the G protein that is associated with random migration.