Pharmacological characterization of recombinant NR1/NR2A NMDA receptors with truncated and deleted carboxy termini expressed in Xenopus laevis oocytes
Pharmacological characterization of recombinant NR1/NR2A NMDA receptors with truncated and deleted carboxy termini expressed in Xenopus laevis oocytes
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DOI：
10.1111/j.1476-5381.2008.00040.x
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发表时间：
2009-02-01
影响因子：
7.3
通讯作者：
Wyllie, D. J. A.
中科院分区：
文献类型：
--
作者：
Puddifoot, C. A.;Chen, P. E.;Wyllie, D. J. A.
NR 2 N-甲基-d-天冬氨酸受体（NMDAR）亚基的羧基末端结构域（CTD）与许多支架和信号转导蛋白相互作用。该区域的突变影响NMDAR的运输和下游信号传导。本研究确定在何种程度上的NR 2A-含NMDARs的药理学特性的影响，这一关键的功能domain.Using重组受体表达非洲爪蟾卵母细胞和两个电极电压钳记录，我们的特点是大鼠NR 1/NR 2A NMDARs与改变CTD的药理学特性。我们评估了截短[在残基Iso 1098; NR 2A（trunC）处]和删除[从残基Phe 822; NR 2A（delC）] NR 2A NMDAR亚基对激动剂效力的CTD，NR 2A NMDAR亚基CTD的截短或缺失不影响谷氨酸效力[EC 50 = 1.50]。2.2 μ mol.L-1，NR 2A（trunC）; 2.7 μ mol.L-1，NR 2A（delC）与3.3 μ mol.L-1，NR 2A（WT）相比]，但显著增加甘氨酸效力[EC 50 = 500 nmol.L-1，NR 2A（trunC）; 900 nmol.L-1，NR 2A（delC）与1.3 μ mol.L-1，NR 2A（WT）相比]。含NR 2A（WT）和NR 2A（trunC）的NMDARs的电压依赖性Mg 2+阻断是相似的，但低浓度的Mg 2+（1 μ mol.L-1）增强了NR 1/NR 2A（delC）NMDARs。NR 2A CTD的结构变化不影响美金刚胺阻滞。EDTA诱导的增强作用是相似的，在每一个的三个NMDAR constructs.Of研究的参数，只有轻微的影响的CTD观察，这些是不太可能妥协的研究，利用CTD突变的重组受体或转基因小鼠在调查的CTD在NMDAR信号的作用的解释。
The carboxy terminal domain (CTD) of NR2 N-methyl-d-aspartate receptor (NMDAR) subunits interacts with numerous scaffolding and signal transduction proteins. Mutations of this region affect trafficking and downstream signalling of NMDARs. This study determines to what extent characteristic pharmacological properties of NR2A-containing NMDARs are influenced by this key functional domain.Using recombinant receptor expression in Xenopus laevis oocytes and two electrode voltage clamp recordings we characterized pharmacological properties of rat NR1/NR2A NMDARs with altered CTDs. We assessed the effects of truncating [at residue Iso1098; NR2A(trunC)] and deleting [from residue Phe822; NR2A(delC)] the CTD of NR2A NMDAR subunits on agonist potencies, channel block by Mg2+ and memantine and potentiation of NMDAR-mediated responses by chelating contaminating divalent cations.Truncation or deletion of the CTD of NR2A NMDAR subunits did not affect glutamate potency [EC50 = 2.2 mu mol.L-1, NR2A(trunC); 2.7 mu mol.L-1, NR2A(delC) compared with 3.3 mu mol.L-1, NR2A(WT)] but did significantly increase glycine potency [EC50 = 500 nmol.L-1, NR2A(trunC); 900 nmol.L-1, NR2A(delC) compared with 1.3 mu mol.L-1, NR2A(WT)]. Voltage-dependent Mg2+ block of NR2A(WT)- and NR2A(trunC)-containing NMDARs was similar but low concentrations of Mg2+ (1 mu mol.L-1) potentiated NR1/NR2A(delC) NMDARs. Memantine block was not affected by changes to the structure of the NR2A CTD. EDTA-induced potentiation was similar at each of the three NMDAR constructs.Of the parameters studied only minor influences of the CTD were observed; these are unlikely to compromise interpretation of studies that make use of CTD-mutated recombinant receptors or transgenic mice in investigations of the role of the CTD in NMDAR signalling.