Activation and assembly of the phagocyte NADPH oxidase.

Upon stimulation of human neutrophils by inflammatory mediators, membrane assembly of the activated NADPH oxidase occurs, as described in “Components and regulation of the phagocyte NADPH oxidase.” The known functional components involved in activation are shown: the integral membrane cytochrome b₅₅₈, consisting of the gp91^phox and p22^phoxsubunits; the cytosolic oxidase components p47^phox, p67^phox, and p40^phox; and the Rac2 GTPase in complex with the regulatory protein GDI (GDP dissociation inhibitor). Multiple regulatory phosphorylations of p47^phox are depicted by the attached 4 P groups; this is not meant to indicate the actual number of phosphorylation sites. Wavy line on Rac2 represents the C-terminal geranylgeranyl isoprenyl group and associated polybasic domain. Portions of this figure have been used in Diebold and Bokoch.47