Assembly of the phagocyte NADPH oxidase

Histochem Cell Biol. 2004 Oct;122(4):277-91. doi: 10.1007/s00418-004-0679-8. Epub 2004 Aug 4.


Stimulated phagocytes undergo a burst in respiration whereby molecular oxygen is converted to superoxide anion through the action of an NADPH-dependent oxidase. The multicomponent phagocyte oxidase is unassembled and inactive in resting cells but assembles at the plasma or phagosomal membrane upon phagocyte activation. Oxidase components include flavocytochrome b558, an integral membrane heterodimer comprised of gp91phox and p22phox, and three cytosolic proteins, p47phox, p67phox, and Rac1 or Rac2, depending on the species and phagocytic cell. In a sense, the phagocyte oxidase is spatially regulated, with critical elements segregated in the membrane and cytosol but ready to undergo nearly immediate assembly and activation in response to stimulation. To achieve such spatial regulation, the individual components in the resting phagocyte adopt conformations that mask potentially interactive structural domains that might mediate productive intermolecular associations and oxidase assembly. In response to stimulation, post-translational modifications of the oxidase components release these constraints and thereby render potential interfaces accessible and interactive, resulting in translocation of the cytosolic elements to the membrane where the functional oxidase is assembled and active. This review summarizes data on the structural features of the phagocyte oxidase components and on the agonist-dependent conformational rearrangements that contribute to oxidase assembly and activation.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Cytochrome b Group / metabolism*
  • Humans
  • NADPH Oxidases / metabolism*
  • Oxygen / metabolism*
  • Phagocytes / enzymology*
  • Phosphoproteins / metabolism
  • Protein Binding
  • Protein Conformation
  • Superoxides / metabolism*
  • rac GTP-Binding Proteins / metabolism
  • rac1 GTP-Binding Protein / metabolism


  • Cytochrome b Group
  • Phosphoproteins
  • Superoxides
  • cytochrome b558
  • NADPH Oxidases
  • rac2 GTP-binding protein
  • rac GTP-Binding Proteins
  • rac1 GTP-Binding Protein
  • Oxygen