The association of metabotropic glutamate receptor type 5 with the neuronal Ca2+-binding protein 2 modulates receptor function

J Neurochem. 2009 Oct;111(2):555-67. doi: 10.1111/j.1471-4159.2009.06348.x. Epub 2009 Aug 18.


Metabotropic glutamate (mGlu) receptors mediate in part the CNS effects of glutamate. These receptors interact with a large array of intracellular proteins in which the final role is to regulate receptor function. Here, using co-immunoprecipitation and pull-down experiments we showed a close and specific interaction between mGlu(5) receptor and NECAB2 in both transfected human embryonic kidney cells and rat hippocampus. Interestingly, in pull-down experiments increasing concentrations of calcium drastically reduced the ability of these two proteins to interact, suggesting that NECAB2 binds to mGlu(5) receptor in a calcium-regulated manner. Immunoelectron microscopy detection of NECAB2 and mGlu(5) receptor in the rat hippocampal formation indicated that both proteins are codistributed in the same subcellular compartment of pyramidal cells. In addition, the NECAB2/mGlu(5) receptor interaction regulated mGlu(5b)-mediated activation of both inositol phosphate accumulation and the extracellular signal-regulated kinase/mitogen-activated protein kinase pathway. Overall, these findings indicate that NECAB2 by its physical interaction with mGlu(5b) receptor modulates receptor function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Calcium / metabolism*
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / immunology
  • Calcium-Binding Proteins / metabolism*
  • Cell Line
  • Hippocampus / cytology
  • Humans
  • Inositol Phosphates / metabolism
  • Kidney / cytology
  • MAP Kinase Signaling System / physiology
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Protein Binding / physiology
  • Pyramidal Cells / cytology
  • Pyramidal Cells / physiology*
  • Rabbits
  • Rats
  • Receptor, Metabotropic Glutamate 5
  • Receptors, Metabotropic Glutamate / genetics
  • Receptors, Metabotropic Glutamate / immunology
  • Receptors, Metabotropic Glutamate / metabolism*
  • Transfection


  • Antibodies
  • Calcium-Binding Proteins
  • Inositol Phosphates
  • NECAB2 protein, human
  • NECAB2 protein, rat
  • Receptor, Metabotropic Glutamate 5
  • Receptors, Metabotropic Glutamate
  • metabotropic glutamate receptor 6
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Calcium