The NR1-4 C-terminus interferes with N-methyl-D-aspartate receptor-mediated excitotoxicity: evidence against a typical T/SXV-PDZ interaction.
The N-methyl-D-aspartate receptor (NMDAR) plays a key role in the neural plasticity that underlies learning and memory in vivo. The plasticity exhibited by NMDARs may also contribute to disease pathogenesis, as a number of disorders are caused or exacerbated by exaggerated NMDAR activity. The NMDAR is composed of two obligatory types of subunits, NR1 and NR2. These transmembrane proteins include large intracellular C-termini that have yet to be fully characterized. We have developed a three-color fluorescence system in order to visualize NMDAR expression in living cells. Using excitotoxicity as a proxy for exaggerated NMDAR activity, we analyzed the effect of over-expressing NR1-4 and NR2A C-terminal domains on exaggerated NMDAR function. We demonstrate that a determinant within the C-terminal domain of NR1-4 (C02') is important for NMDAR excitotoxicity, whereas no novel determinants were identified in the NR2A C-terminus. Through the use of heterologous cells, and by examining the interaction between the prototypical NMDAR-binding partner postsynaptic density-95 (PSD-95), we show that this effect is unlikely to be mediated through a classical interaction with PSD-95.
Mattar
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PA
The BioTherapeutics Research Group, Robarts Research Institute, P.O. Box 5015, 100 Perth Drive, London, Ontario, Canada N6A 5K8.
Holmes
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KD
Dekaban
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GA
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D003001:Cloning, Molecular / Q000379:methods; D000076122:Disks Large Homolog 4 Protein; D004347:Drug Interactions; D005434:Flow Cytometry / Q000379:methods; D005455:Fluorescent Antibody Technique / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D005822:Genetic Vectors / Q000494:pharmacology / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007649:Ketamine / Q000494:pharmacology*; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009498:Neurotoxins / Q000494:pharmacology*; D010446:Peptide Fragments / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry / Q000145:classification / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D014162:Transfection / Q000379:methods
D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009498:Neurotoxins; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; D011993:Recombinant Fusion Proteins; C033652:postsynaptic density proteins; D007649:Ketamine