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Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels
16:36

Proteomics to Identify Proteins Interacting with P2X2 Ligand-Gated Cation Channels

Published on: May 18, 2009

Homotrimeric complexes are the dominant assembly state of native P2X7 subunits

Annette Nicke1

  • 1Max Planck Institute for Brain Research, Dept. of Neurochemistry, Deutschordenstr. 46, 60528 Frankfurt, Germany. anicke@gwdg.de

Biochemical and Biophysical Research Communications
|October 22, 2008
PubMed

Insights

This study investigated P2X4 and P2X7 receptors, finding they form distinct trimeric complexes. Evidence suggests P2X4/7 heteromers are not stable or dominant in native tissues, impacting pain research.

Area of Science:

  • Molecular biology
  • Neuroscience
  • Immunology

Background:

  • P2X receptors (P2XRs) are ATP-gated cation channels crucial in various physiological and pathophysiological processes.
  • P2X4 and P2X7 subunits are implicated in inflammatory and neuropathic pain, with overlapping expression patterns.
  • Recent evidence suggested the existence of heteromeric P2X4/7 receptors.

Purpose of the Study:

  • To directly visualize and characterize native P2X receptor complexes, specifically P2X7 and P2X4.
  • To investigate the potential formation and stability of heteromeric P2X4/7 receptor complexes.

Main Methods:

  • Utilized subtype-specific antibodies for P2X7R and P2X4R.
  • Employed Blue Native-PAGE (BN-PAGE) to separate and visualize protein complexes from native tissue membrane extracts.

Main Results:

  • Successfully visualized distinct P2X7R and P2X4R complexes in various tissues.
  • P2X7 complexes and P2X4 complexes exhibited different sizes but were both trimeric.
  • No evidence of complexes larger than three subunits or intermediate-sized complexes reactive to both antibodies was found.

Conclusions:

  • Native P2X7R and P2X4R receptors form stable, homomeric trimeric complexes.
  • The data suggest that stable P2X4/7 heteromeric complexes are either not formed or are not a dominant subtype in the investigated native tissues.
  • This finding has implications for understanding the roles of P2X4 and P2X7 in pain and inflammation.

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