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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

A protein kinase C site highly conserved in P2X subunits controls the desensitization kinetics of P2X(2) ATP-gated

E Boué-Grabot1, V Archambault, P Séguéla

  • 1Department of Neurology and Neurosurgery, Cell Biology of Excitable Tissue Research Group, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada.

The Journal of Biological Chemistry
|April 1, 2000
PubMed

Insights

Protein kinase C phosphorylation of P2X receptors regulates their desensitization rate. This study identifies a conserved N-terminal site critical for slow desensitization in ATP-gated ion channels.

Area of Science:

  • Molecular biology
  • Neuroscience
  • Biochemistry

Background:

  • P2X receptors are ATP-gated ion channels.
  • Subunit composition influences P2X receptor kinetics.

Purpose of the Study:

  • Identify determinants of slow desensitization in rat P2X(2) receptors.
  • Investigate the role of protein kinase C (PKC) in P2X receptor kinetics.

Main Methods:

  • Site-directed mutagenesis of P2X(2) subunits.
  • Voltage clamp electrophysiology in Xenopus oocytes.
  • Immunodetection of phosphothreonine.

Main Results:

  • A conserved PKC site (TX(K/R)) in the N-terminus is crucial for slow desensitization.
  • Mutant receptors lacking this site desensitize rapidly.
  • PKC activation converts rapidly desensitizing currents to slowly desensitizing ones in truncated mutants.
  • Phosphorylation of Thr(18) by PKC was confirmed.

Conclusions:

  • PKC-mediated phosphorylation of the N-terminal threonine residue is essential for slow desensitization of P2X(2) receptors.
  • Cytoplasmic domain interactions also contribute to slow desensitization kinetics.

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