PKCε phosphorylation of the sodium channel NaV1.8 increases channel function and produces mechanical hyperalgesia in mice

J Clin Invest. 2012 Apr;122(4):1306-15. doi: 10.1172/JCI61934. Epub 2012 Mar 19.

Abstract

Mechanical hyperalgesia is a common and potentially disabling complication of many inflammatory and neuropathic conditions. Activation of the enzyme PKCε in primary afferent nociceptors is a major mechanism that underlies mechanical hyperalgesia, but the PKCε substrates involved downstream are not known. Here, we report that in a proteomic screen we identified the NaV1.8 sodium channel, which is selectively expressed in nociceptors, as a PKCε substrate. PKCε-mediated phosphorylation increased NaV1.8 currents, lowered the threshold voltage for activation, and produced a depolarizing shift in inactivation in wild-type - but not in PKCε-null - sensory neurons. PKCε phosphorylated NaV1.8 at S1452, and alanine substitution at this site blocked PKCε modulation of channel properties. Moreover, a specific PKCε activator peptide, ψεRACK, produced mechanical hyperalgesia in wild-type mice but not in Scn10a-/- mice, which lack NaV1.8 channels. These studies demonstrate that NaV1.8 is an important, direct substrate of PKCε that mediates PKCε-dependent mechanical hyperalgesia.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Action Potentials
  • Amino Acid Substitution
  • Animals
  • Cells, Cultured / drug effects
  • Ganglia, Spinal / cytology
  • Hyperalgesia / enzymology
  • Hyperalgesia / etiology*
  • Ion Channel Gating
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mutation, Missense
  • NAV1.8 Voltage-Gated Sodium Channel
  • Point Mutation
  • Protein Kinase C-epsilon / analysis
  • Protein Kinase C-epsilon / genetics
  • Protein Kinase C-epsilon / physiology*
  • Protein Processing, Post-Translational*
  • Rats
  • Sensory Receptor Cells / enzymology
  • Sensory Receptor Cells / physiology*
  • Sodium / metabolism
  • Sodium Channels / analysis
  • Sodium Channels / chemistry
  • Sodium Channels / deficiency
  • Sodium Channels / genetics
  • Sodium Channels / physiology*
  • Stress, Mechanical
  • Substrate Specificity

Substances

  • NAV1.8 Voltage-Gated Sodium Channel
  • Scn10a protein, mouse
  • Scn10a protein, rat
  • Sodium Channels
  • Sodium
  • Prkce protein, mouse
  • Prkce protein, rat
  • Protein Kinase C-epsilon