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.
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.
Luthi-Carter
Ruth
R
MassGeneral Institute for Neurodegenerative Diseases, B114-2000, 114 16th Street, Charlestown, MA 02129-4404, USA.
Apostol
Barbara L
BL
Dunah
Anthone W
AW
DeJohn
Molly M
MM
Farrell
Laurie A
LA
Bates
Gillian P
GP
Young
Anne B
AB
Standaert
David G
DG
Thompson
Leslie M
LM
Cha
Jang Ho J
JH
D000185:Actinin / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D000076122:Disks Large Homolog 4 Protein; D051528:Guanylate Kinases; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D017434:Protein Structure, Tertiary / Q000235:genetics; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics* / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
C498529:Actn2 protein, mouse; D000076122:Disks Large Homolog 4 Protein; C501447:Dlg4 protein, mouse; C501449:Dlg4 protein, rat; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C409466:NR1 NMDA receptor; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; C033652:postsynaptic density proteins; D000185:Actinin; D014443:Tyrosine; D051528:Guanylate Kinases