GluN2B-Containing NMDA Receptors Regulate AMPA Receptor Traffic through Anchoring of the Synaptic Proteasome

J Neurosci. 2015 Jun 3;35(22):8462-79. doi: 10.1523/JNEUROSCI.3567-14.2015.


NMDA receptors play a central role in shaping the strength of synaptic connections throughout development and in mediating synaptic plasticity mechanisms that underlie some forms of learning and memory formation in the CNS. In the hippocampus and the neocortex, GluN1 is combined primarily with GluN2A and GluN2B, which are differentially expressed during development and confer distinct molecular and physiological properties to NMDA receptors. The contribution of each subunit to the synaptic traffic of NMDA receptors and therefore to their role during development and in synaptic plasticity is still controversial. We report a critical role for the GluN2B subunit in regulating NMDA receptor synaptic targeting. In the absence of GluN2B, the synaptic levels of AMPA receptors are increased and accompanied by decreased constitutive endocytosis of GluA1-AMPA receptor. We used quantitative proteomic analysis to identify changes in the composition of postsynaptic densities from GluN2B(-/-) mouse primary neuronal cultures and found altered levels of several ubiquitin proteasome system components, in particular decreased levels of proteasome subunits. Enhancing the proteasome activity with a novel proteasome activator restored the synaptic levels of AMPA receptors in GluN2B(-/-) neurons and their endocytosis, revealing that GluN2B-mediated anchoring of the synaptic proteasome is responsible for fine tuning AMPA receptor synaptic levels under basal conditions.

Keywords: AMPA receptors; GluN2B; NMDA receptors; iTRAQ; postsynaptic density; proteasome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / cytology*
  • Cells, Cultured
  • Endocytosis / physiology
  • Excitatory Amino Acid Agents / pharmacology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / genetics
  • Hydrazones / pharmacology
  • Mice
  • Mice, Transgenic
  • Nerve Tissue Proteins / metabolism
  • Neuronal Plasticity / physiology
  • Neurons / metabolism*
  • Proteasome Endopeptidase Complex / genetics
  • Proteasome Endopeptidase Complex / metabolism
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Protein Transport / genetics
  • Receptors, AMPA / metabolism*
  • Receptors, N-Methyl-D-Aspartate / genetics
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology
  • Subcellular Fractions / metabolism
  • Subcellular Fractions / ultrastructure
  • Synapses / drug effects
  • Synapses / metabolism*
  • Tetrodotoxin / pharmacology
  • Time Factors
  • ras GTPase-Activating Proteins / metabolism


  • Excitatory Amino Acid Agents
  • Hydrazones
  • N'-(3,4-dihydroxybenzylidene)-3-hydroxy-2-naphthahydrazide
  • NR2B NMDA receptor
  • Nerve Tissue Proteins
  • Protein Subunits
  • Receptors, AMPA
  • Receptors, N-Methyl-D-Aspartate
  • Syngap1 protein, mouse
  • ras GTPase-Activating Proteins
  • Tetrodotoxin
  • Proteasome Endopeptidase Complex