Regulation of phagocyte NADPH oxidase activity: identification of two cytochrome b 558 activation states

2007 ◽  
Vol 21 (4) ◽  
pp. 1244-1255 ◽  
Author(s):  
Marie-Héiène Paclet ◽  
Sylvie Berthier ◽  
Lauriane Kuhn ◽  
Jérôme Garin ◽  
Françoise Morel
Keyword(s):  
Nadph Oxidase ◽  
Cytochrome B ◽  
Oxidase Activity ◽  
Nadph Oxidase Activity ◽  
Phagocyte Nadph Oxidase

scholarly journals FcγR-stimulated activation of the NADPH oxidase: phosphoinositide-binding protein p40phox regulates NADPH oxidase activity after enzyme assembly on the phagosome

Blood ◽  
2008 ◽  
Vol 112 (9) ◽  
pp. 3867-3877 ◽  
Author(s):  
Wei Tian ◽  
Xing Jun Li ◽  
Natalie D. Stull ◽  
Wenyu Ming ◽  
Chang-Il Suh ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Superoxide Production ◽  
Resting Cells ◽  
Cellular Activation ◽  
Nadph Oxidase Activity ◽  
Phagocyte Nadph Oxidase ◽  
Before And After ◽  
Membrane Bound

AbstractThe phagocyte NADPH oxidase generates superoxide for microbial killing, and includes a membrane-bound flavocytochrome b558 and cytosolic p67phox, p47phox, and p40phox subunits that undergo membrane translocation upon cellular activation. The function of p40phox, which binds p67phox in resting cells, is incompletely understood. Recent studies showed that phagocytosis-induced superoxide production is stimulated by p40phox and its binding to phosphatidylinositol-3-phosphate (PI3P), a phosphoinositide enriched in membranes of internalized phagosomes. To better define the role of p40phox in FcγR-induced oxidase activation, we used immunofluorescence and real-time imaging of FcγR-induced phagocytosis. YFP-tagged p67phox and p40phox translocated to granulocyte phagosomes before phagosome internalization and accumulation of a probe for PI3P. p67phox and p47phox accumulation on nascent and internalized phagosomes did not require p40phox or PI3 kinase activity, although superoxide production before and after phagosome sealing was decreased by mutation of the p40phox PI3P-binding domain or wortmannin. Translocation of p40phox to nascent phagosomes required binding to p67phox but not PI3P, although the loss of PI3P binding reduced p40phox retention after phagosome internalization. We conclude that p40phox functions primarily to regulate FcγR-induced NADPH oxidase activity rather than assembly, and stimulates superoxide production via a PI3P signal that increases after phagosome internalization.

scholarly journals Composition of partially purified NADPH oxidase from pig neutrophils

1984 ◽  
Vol 223 (3) ◽  
pp. 639-648 ◽  
Author(s):  
P Bellavite ◽  
O T G Jones ◽  
A R Cross ◽  
E Papini ◽  
F Rossi
Keyword(s):  
Enzyme Activity ◽  
Cytochrome C ◽  
Nadph Oxidase ◽  
Cytochrome B ◽  
Oxidase Activity ◽  
Gel Filtration ◽  
Purification Procedure ◽  
Nadph Oxidase Activity ◽  
Cytochrome C Reductase

The superoxide (O2.-)-forming enzyme NADPH oxidase from pig neutrophils was solubilized and partially purified by gel-filtration chromatography. The purification procedure allowed the separation of NADPH oxidase activity from NADH-dependent cytochrome c reductase and 2,6-dichlorophenol-indophenol reductase activities. O2.-forming activity was co-purified with cytochrome b-245 and was associated with phospholipids. However, active fractions endowed with cytochrome b were devoid of ubiquinone and contained only little FAD. The cytochrome b/FAD ratio was 1.13:1 in the crude solubilized extract and increased to 18.95:1 in the partially purified preparations. Most of FAD was associated with fractions containing NADH-dependent oxidoreductases. These results are consistent with the postulated role of cytochrome b in O2.-formation by neutrophil NADPH oxidase, but raise doubts about the participation of flavoproteins in this enzyme activity.

scholarly journals Cholesterol: A modulator of the phagocyte NADPH oxidase activity - A cell-free study

Redox Biology ◽  
2014 ◽  
Vol 3 ◽  
pp. 16-24 ◽  
Author(s):  
Rawand Masoud ◽  
Tania Bizouarn ◽  
Chantal Houée-Levin
Keyword(s):  
Nadph Oxidase ◽  
Oxidase Activity ◽  
Nadph Oxidase Activity ◽  
Phagocyte Nadph Oxidase ◽  
A Cell
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