Pervanadate Activates NADPH Oxidase via Protein Kinase C-Independent Phosphorylation of p47-phox

We studied differences between the NADPH oxidase activation pathways triggered by pervanadate, a protein tyrosine phosphatase inhibitor, and phorbol 12-myristate 13-acetate (PMA), a protein kinase C activator, in guinea pig neutrophils. Previously, pervanadate has been shown to activate NADPH oxidase via the tyrosine kinase-dependent pathway (Yamaguchiet al. Arch. Biochem. Biophys.323, 382–386, 1995). Both pervanadate and PMA induced superoxide anion (O−2) production, translocation of the 47-kDa protein component of the phagocyte oxidase (p47-phox) to the plasma membrane, and phosphorylation of p47-phox in the membrane. A selective protein kinase C inhibitor, GF 109203X, markedly inhibited PMA-induced O−2production, p47-phox translocation, and p47-phox phosphorylation, but did not inhibit pervanadate-induced O−2production and only slightly suppressed pervanadate-induced translocation and phosphorylation. These results demonstrate that pervanadate activates NADPH oxidase independently of protein kinase C. Phosphopeptide mapping of p47-phox revealed differences in the mechanism between pervanadate-induced and PMA-induced phosphorylation. Furthermore, some protein kinases which phosphorylate p47-phox-derived peptide are activated by pervanadate. These results suggest the existence of novel protein kinases responsible for the phosphorylation of p47-phox and the activation of these protein kinases by tyrosine kinase.