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Bioluminescence Imaging of NADPH Oxidase Activity in Different Animal Models
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Bioluminescence Imaging of NADPH Oxidase Activity in Different Animal Models

Published on: October 22, 2012

Molecular basis of phosphorylation-induced activation of the NADPH oxidase

Yvonne Groemping1, Karine Lapouge, Stephen J Smerdon

  • 1Division of Protein Structure, National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.

Cell
|May 7, 2003
PubMed

Insights

The NADPH oxidase complex is vital for fighting infections. Its activation involves p47(phox) protein rearrangement, allowing it to bind to other components and produce reactive oxygen species for host defense.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Immunology

Background:

  • The NADPH oxidase (NOX) complex generates reactive oxygen species (ROS) essential for host defense against microbial pathogens.
  • Activation of the NOX complex requires assembly of cytosolic factors (p40-p47-p67phox) with membrane-bound proteins (p22-gp91phox).
  • The cytosolic p47phox subunit exists in an auto-inhibited state, preventing premature NOX complex assembly.

Purpose of the Study:

  • To elucidate the structural mechanisms underlying the auto-inhibition of p47phox.
  • To understand how phosphorylation regulates p47phox conformation and NOX complex activation.
  • To provide insights into the molecular switch controlling NOX enzyme assembly.

Main Methods:

  • X-ray crystallography to determine the structure of auto-inhibited p47phox.
  • Biochemical assays to investigate protein interactions and phosphorylation effects.
  • Structural analysis of SH3 domains and their role in auto-inhibition.

Main Results:

  • The crystal structure revealed that tandem SH3 domains in p47phox maintain an auto-inhibited conformation.
  • Phosphorylation of p47phox acts as a molecular switch, relieving intramolecular inhibition.
  • This conformational change enables p47phox interaction with p22phox, initiating NOX complex assembly and ROS production.

Conclusions:

  • The SH3 domains of p47phox are critical for maintaining the resting state of the NADPH oxidase complex.
  • Phosphorylation-dependent conformational changes in p47phox are essential for NOX activation.
  • Understanding this regulatory mechanism provides targets for modulating immune responses.

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