1. Complex alteration of NMDA receptors in transgenic Huntington's disease mouse brain: analysis of mRNA and protein expression, plasma membrane association, interacting proteins, and phosphorylation.
- Author
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Luthi-Carter R, Apostol BL, Dunah AW, DeJohn MM, Farrell LA, Bates GP, Young AB, Standaert DG, Thompson LM, and Cha JH
- Subjects
- Actinin metabolism, Animals, Brain pathology, Brain physiopathology, Cell Membrane genetics, Cell Membrane metabolism, Disease Models, Animal, Disks Large Homolog 4 Protein, Guanylate Kinases, Huntingtin Protein, Huntington Disease genetics, Huntington Disease physiopathology, Intracellular Signaling Peptides and Proteins, Membrane Proteins, Mice, Mice, Transgenic, Mutation genetics, Nerve Tissue Proteins metabolism, Nuclear Proteins metabolism, Phosphorylation, Protein Structure, Tertiary genetics, Protein Subunits metabolism, Protein Transport physiology, RNA, Messenger metabolism, Receptors, N-Methyl-D-Aspartate metabolism, Tyrosine metabolism, Brain metabolism, Huntington Disease metabolism, Nerve Tissue Proteins genetics, Nuclear Proteins genetics, Protein Subunits genetics, Receptors, N-Methyl-D-Aspartate genetics
- Abstract
We analyzed NMDA receptor subunit mRNAs, proteins, and anchoring proteins in mice transgenic for exon 1 of the HD gene. R6/2 mice had decreased levels of mRNAs encoding epsilon1 and epsilon2 NMDA receptor subunits (mouse orthologs of rat NR2A and NR2B subunits), but not the zeta1 subunit (mouse ortholog of NR1), as assessed by gene expression profiling and Northern blotting. In situ hybridization resolved mRNA decreases spatially to the CA1 field of hippocampus. Western blotting revealed decreases in plasma membrane-associated epsilon1 and epsilon2 subunits in hippocampus, and decreases in plasma membrane-associated zeta1 subunit in cortex and hippocampus. In addition, PSD-95 and alpha-actinin-2, proteins essential for anchoring NMDA receptors, were decreased. Finally, we found a decreased level of tyrosine-phosphorylated epsilon1 subunit, another determinant of NMDA receptor trafficking, in R6/2 hippocampus. Taken together, these data demonstrate multiple levels of NMDA receptor dysregulation, including abnormalities in mRNA expression levels, receptor stoichiometry, protein phosphorylation, and receptor trafficking.
- Published
- 2003
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