Alteration of Ca2+ permeability and sensitivity to Mg2+ and channel blockers by a single amino acid substitution in the N-methyl-D-aspartate receptor.
Alteration of Ca2+ permeability and sensitivity to Mg2+ and channel blockers by a single amino acid substitution in the N-methyl-D-aspartate receptor.
复制标题
通过 N-甲基-D-天冬氨酸受体中的单个氨基酸取代，改变 Ca2+ 通透性以及对 Mg2+ 和通道阻滞剂的敏感性。
DOI：
10.1016/s0021-9258(18)54166-1
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
S. Nakanishi
中科院分区：
文献类型：
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作者：
Kazuhiro Sakurada;Masayuki Masu;S. Nakanishi
N-甲基-D-天冬氨酸（NMDA）受体在谷氨酸介导的中枢神经系统神经元可塑性和神经毒性中起重要作用。该受体由基本亚基（NMDAR 1）及其增强亚基（NMDAR 2A-NMDAR 2D）组成。NMDA受体与其他谷氨酸受体通道不同，因为其具有高Ca 2+渗透性，并可被选择性阳离子通道阻断剂（如Mg 2+、Zn 2+和MK-801）抑制。在这项研究中，我们调查的结构特点，控制Ca 2+渗透和通道阻滞的NMDA受体在体外诱变和表达在非洲爪蟾卵母细胞。我们构建了一系列的突变与NMDAR 1的第二个跨膜段中的单个氨基酸取代，并检查所得到的突变体与NMDAR 2A亚基的组合表达的通道特性。用谷氨酰胺或精氨酸取代天冬酰胺改变了Ca 2+渗透性和对Mg 2+和MK-801阻断的敏感性。这些突变也降低了Zn 2+和抗抑郁药地昔帕明的抑制作用。基于这些结果，我们得出的结论是，在形成通道的第二跨膜段的中心部分形成的天冬酰胺环在确定Ca 2+渗透性和抑制开放通道阻滞剂中起着关键作用。
The N-methyl-D-aspartate (NMDA) receptor plays an important role in glutamate-mediated neuronal plasticity and neurotoxicity in the central nervous system. This receptor is composed of a fundamental subunit (NMDAR1) and its potentiating subunits (NMDAR2A-NMDAR2D). The NMDA receptor is distinct from other glutamate receptor channels because of its high Ca2+ permeability and inhibition by selective cationic channel blockers such as Mg2+, Zn2+, and MK-801. In this study, we investigated the structural features that control Ca2+ permeation and channel blockade of the NMDA receptor by in vitro mutagenesis and expression in Xenopus oocytes. We constructed a series of mutations with single amino acid substitutions in the second transmembrane segment of NMDAR1 and examined channel properties of the resultant mutants in combined expression with the NMDAR2A subunit. Substitution of the asparagine with either glutamine or arginine altered both the Ca2+ permeability and the sensitivity to blockades by Mg2+ and MK-801. These mutations also reduced the inhibitory effects of Zn2+ and an antidepressant, desipramine. Based on these results, we concluded that an asparagine ring formed in the central part of the channel-forming second transmembrane segments plays a critical role in determining the Ca2+ permeability and the inhibition of open channel blockers.