title: Phosphoinositide 3-kinase regulates the phosphorylation of NADPH oxidase component p47(phox) by controlling cPKC/PKCdelta but not Akt.
abstract: Superoxide production by NADPH oxidase is essential for the bactericidal properties of phagocytes. Phosphorylation of p47(phox), one of the cytosolic components of NADPH oxidase, is a crucial step of the oxidase activation. Some evidences suggest that phosphoinositide 3-kinase (PI3K) is involved in p47(phox) phosphorylation, but it has not been fully understood how PI3K regulates it. The aim of this study was to examine the mechanism underlying the PI3K regulation of p47(phox) phosphorylation. Pharmacological inhibition of PI3K attenuated both fMLP-stimulated p47(phox) phosphorylation and NADPH oxidase activity in HL-60 cells differentiated to a neutrophil-like phenotype. Although fMLP elicited Akt activation in a PI3K-dependent manner, an Akt inhibitor had no effect on the oxidase activity triggered by fMLP. In vitro kinase assay revealed that Akt was unable to catalyze p47(phox) phosphorylation. Interestingly, the activation of cPKC and PKCdelta after fMLP stimulation was dependent on PI3K. Furthermore, PI3K inhibitors reduced the activation of phospholipase Cgamma2 without affecting tyrosine phosphorylation on it. These results suggest that PI3K regulates the phosphorylation of NADPH oxidase component p47(phox) by controlling diacylglycerol-dependent PKCs but not Akt.
authors.affiliation: Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Yamamori
authors.forename: Osamu
authors.initials: O
authors.lastname: Inanami
authors.forename: Hajime
authors.initials: H
authors.lastname: Nagahata
authors.forename: Mikinori
authors.initials: M
authors.lastname: Kuwabara
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D003600:Cytosol / Q000201:enzymology / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005982:Glutathione Transferase / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D015151:Immunoblotting; D008264:Macrophages / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D009000:Monocytes / Q000378:metabolism; D009025:Morpholines / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism*; D009504:Neutrophils / Q000166:cytology; D010641:Phenotype; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism / Q000502:physiology*; D051966:Phospholipase C gamma; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors; D010738:Type C Phospholipases / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D002867:Chromones; D018076:DNA, Complementary; D004791:Enzyme Inhibitors; D005982:Glutathione Transferase; D009025:Morpholines; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; D019869:Phosphatidylinositol 3-Kinases; D051966:Phospholipase C gamma; D010750:Phosphoproteins; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011994:Recombinant Proteins; D013481:Superoxides; D010738:Type C Phospholipases; D014443:Tyrosine; D000077191:Wortmannin; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C060505:neutrophil cytosolic factor 1; C497259:Prkcd protein, mouse; C494918:AKT1 protein, human; C497258:PRKCD protein, human