Delineation of additional PSD-95 binding domains within NMDA receptor NR2 subunits reveals differences between NR2A/PSD-95 and NR2B/PSD-95 association.
N-methyl-D-aspartate (NMDA) receptors are clustered at synapses via their association with the PSD-95 (post-synaptic density-95) membrane associated guanylate kinase (MAGUK) family of scaffolding proteins. PSD-95 is the best characterized of this family. It is known to associate with NMDA receptor NR2 subunits via a conserved ES(E/D)V amino acid sequence located at their C-termini and thus to promote the clustering, regulation and the trafficking of assembled NR1/NR2 NMDA receptors at synapses. Here we have investigated in more detail NMDA receptor NR2/PSD-95 protein-protein association. Wild-type NR1 and PSD-95alpha were co-expressed with a series of rodent C-terminal truncated constructs of either NR2A or NR2B subunits in human embryonic kidney (HEK) 293 cells and the association of PSD-95alpha with assembled receptors determined by immunoprecipitation. Additional PSD-95 binding domains that differed between NR2A and NR2B subunits were identified. These domains mapped to the amino acid sequences NR2A (1382-1420) and NR2B (1086-1157). These results suggest that NR2A and NR2B may associate with PSD-95 but with different affinities. This may be important in the determination of the lateral mobility of NMDA receptor subtypes in post-synaptic membranes.
Cousins
S L
SL
School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, UK.
Kenny
A V
AV
Stephenson
F A
FA
D000595:Amino Acid Sequence / Q000502:physiology; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002460:Cell Line; D000076122:Disks Large Homolog 4 Protein; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D046911:Macromolecular Substances / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry / Q000378:metabolism*; D012377:Rodentia; D017386:Sequence Homology, Amino Acid; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D013570:Synaptic Membranes / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology
C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate