Palmitoylation at two cysteine clusters on the C-terminus of GluN2A and GluN2B differentially control synaptic targeting of NMDA receptors

PLoS One. 2012;7(11):e49089. doi: 10.1371/journal.pone.0049089. Epub 2012 Nov 15.

Abstract

Palmitoylation of NMDARs occurs at two distinct cysteine clusters in the carboxyl-terminus of GluN2A and GluN2B subunits that differentially regulates retention in the Golgi apparatus and surface expression of NMDARs. Mutations of palmitoylatable cysteine residues in the membrane-proximal cluster to non-palmitoylatable serines leads to a reduction in the surface expression of recombinant NMDARs via enhanced internalization of the receptors. Mutations in a cluster of cysteines in the middle of the carboxyl-terminus of GluN2A and GluN2B, leads to an increase in the surface expression of NMDARs via an increase in post-Golgi trafficking. Using a quantitative electrophysiological assay, we investigated whether palmitoylation of GluN2 subunits and the differential regulation of surface expression affect functional synaptic incorporation of NMDARs. We show that a reduction in surface expression due to mutations in the membrane-proximal cluster translates to a reduction in synaptic expression of NMDARs. However, increased surface expression induced by mutations in the cluster of cysteines that regulates post-Golgi trafficking of NMDARs does not increase the synaptic pool of NMDA receptors, indicating that the number of synaptic receptors is tightly regulated.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Membrane / metabolism*
  • Cysteine / metabolism
  • Electric Stimulation
  • Golgi Apparatus / metabolism
  • Hippocampus / metabolism
  • Lipoylation
  • Mutation / genetics
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / genetics
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Synapses / metabolism*

Substances

  • NR2B NMDA receptor
  • Receptors, N-Methyl-D-Aspartate
  • Cysteine
  • N-methyl D-aspartate receptor subtype 2A