Cousins S L, Kenny A V, Stephenson F A
School of Pharmacy, University of London, 29/39 Brunswick Square, London WC1N 1AX, UK.
Neuroscience. 2009 Jan 12;158(1):89-95. doi: 10.1016/j.neuroscience.2007.12.051. Epub 2008 Jan 19.
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.
N-甲基-D-天冬氨酸（NMDA）受体通过与突触后致密物-95（PSD-95）膜相关鸟苷酸激酶（MAGUK）家族的支架蛋白结合，聚集在突触处。PSD-95是该家族中研究最为深入的成员。已知它通过位于其C末端的保守ES(E/D)V氨基酸序列与NMDA受体NR2亚基结合，从而促进组装好的NR1/NR2 NMDA受体在突触处的聚集、调节和运输。在此，我们更详细地研究了NMDA受体NR2/PSD-95的蛋白质-蛋白质相互作用。野生型NR1和PSD-95α与一系列啮齿动物NR2A或NR2B亚基的C末端截短构建体在人胚肾（HEK）293细胞中共表达，并通过免疫沉淀法确定PSD-95α与组装好的受体之间的相互作用。鉴定出了NR2A和NR2B亚基之间不同的额外PSD-95结合结构域。这些结构域定位于氨基酸序列NR2A（1382 - 1420）和NR2B（1086 - 1157）。这些结果表明，NR2A和NR2B可能与PSD-95结合，但亲和力不同。这可能对确定NMDA受体亚型在突触后膜中的侧向移动性很重要。
