Palmitoylation of the GluR6 kainate receptor

Proc Natl Acad Sci U S A. 1995 Dec 19;92(26):12090-4. doi: 10.1073/pnas.92.26.12090.

Abstract

The G-protein-coupled metabotropic glutamate receptor mGluR1 alpha and the ionotropic glutamate receptor GluR6 were examined for posttranslational palmitoylation. Recombinant receptors were expressed in baculovirus-infected insect cells or in human embryonic kidney cells and were metabolically labeled with [3H]palmitic acid. The metabotropic mGluR1 alpha receptor was not labeled whereas the GluR6 kainate receptor was labeled after incubation with [3H]palmitate. The [3H]palmitate labeling of GluR6 was eliminated by treatment with hydroxylamine, indicating that the labeling was due to palmitoylation at a cysteine residue via a thioester bond. Site-directed mutagenesis was used to demonstrate that palmitoylation of GluR6 occurs at two cysteine residues, C827 and C840, located in the carboxyl-terminal domain of the molecule. A comparison of the electrophysiological properties of the wild-type and unpalmitoylated mutant receptor (C827A, C840A) showed that the kainate-gated currents produced by the unpalmitoylated mutant receptor were indistinguishable from those of the wild-type GluR6. The unpalmitoylated mutant was a better substrate for protein kinase C than the wild-type GluR6 receptor. These data indicate that palmitoylation may not modulate kainate channel function directly but instead affect function indirectly by regulating the phosphorylation state of the receptor.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine
  • Animals
  • Autoradiography / methods
  • Base Sequence
  • Cell Line
  • Cysteine
  • DNA, Complementary
  • Embryo, Mammalian
  • Embryo, Nonmammalian
  • Humans
  • Kidney
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Oligodeoxyribonucleotides
  • Open Reading Frames
  • Palmitic Acid
  • Palmitic Acids / metabolism*
  • Phosphorylation
  • Point Mutation
  • Protein Kinase C / metabolism
  • Protein Processing, Post-Translational*
  • Receptors, Kainic Acid / biosynthesis
  • Receptors, Kainic Acid / metabolism*
  • Receptors, Kainic Acid / physiology
  • Receptors, Metabotropic Glutamate / biosynthesis
  • Receptors, Metabotropic Glutamate / metabolism*
  • Receptors, Metabotropic Glutamate / physiology
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / metabolism
  • Spodoptera
  • Transfection
  • Tritium

Substances

  • DNA, Complementary
  • Gluk2 kainate receptor
  • Oligodeoxyribonucleotides
  • Palmitic Acids
  • Receptors, Kainic Acid
  • Receptors, Metabotropic Glutamate
  • Recombinant Proteins
  • Tritium
  • Palmitic Acid
  • Protein Kinase C
  • Cysteine
  • Alanine