Roles of p38 MAPK, PKC and PI3-K in the signaling pathways of NADPH oxidase activation and phagocytosis in bovine polymorphonuclear leukocytes

Stimulation of bovine polymorphonuclear leukocytes (PMN) with serum-opsoniz ed zymosan (sOZ) induced the activation of p38 mitogen-activated protein ki nase (MAPK), protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3- K) and sOZ-induced O-2(-) production was significantly attenuated by their inhibitors (SB203580 for p38 MAPK, GF109203X for PBC and wortmannin for PD- K). They caused significant attenuation of sOZ-induced phosphorylation of p 47phox as well, Flow cytometric analysis, however, revealed that SB203580 a nd wortmannin attenuated phagocytosis, but GF109203X facilitated it. The re sults suggest that p38 MAPK and PI3-K participated in both signaling pathwa ys of NADPH oxidase activation (O-2(-) production) and phagocytosis, and PK C participated in the signaling pathway of NADPH oxidase activation alone, (C) 2000 Federation of European Biochemical Societies.