人源谷氨酸转运蛋白EAAT2的结构研究
夏凌云#，张媛媛#，施 仪#，黄 晶*，周 强*
（1.西湖大学未来产业中心，生命科学学院，浙江省结构生物学重点实验室，浙江 杭州 310024；2. 西湖实验室（生命科学和生物医学浙江省实验室），浙江 杭州 310024；3. 浙江西湖高等研究院，生物学研究所，浙江 杭州 310024）
摘 要 谷氨酸是脊椎动物神经系统中的主要兴奋性神经递质，它启动快速信号传递并涉及学习、记忆和突触可塑性。信号传递的最后一步也是至关重要的一步，是从突触间隙迅速清除释放的谷氨酸，以防止神经元的兴奋毒性，这主要是由兴奋性氨基酸转运体2（EAAT2）完成的。这里描述了人类EAAT2向内开口的结构，包括具有开放HP2门的无配体构象，抑制剂阻断的开放构象以及激活剂结合的闭合构象。这些结构显示EAAT2向胞内转运神经递质后，抑制剂WAY-213613通过竞争底物结合位点，将其阻断在向内开口且HP2环开放的构象，抑制其反向转运过程。而激活剂GT949或许能加速这一过程。这些结构信息提供了配体位置和EAAT2活性调节机制的分子细节。总之，这些结构数据为研究EAAT结构-功能关系和设计新型治疗调节剂奠定了基础。
关键词 谷氨酸转运蛋白；SLC1A2；神经退行性疾病；冷冻电镜结构
中图分类号：Q518.2；R589.3 ；R596 文献标识码：ADoi:10.3969/j.issn.1000-6281.2025.01.009
Structural study of human glutamate transporter EAAT2
XIA Lingyun#，ZHANG Yuanyuan#，SHI Yi#，HUANG Jing*，ZHOU Qiang*
（1. Research Center for Industries of the Future, Zhejiang Key Laboratory of Structural Biology, School of Life Sciences, Westlake University, Hangzhou Zhejiang 310024；2. Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou Zhejiang 310024；3. Institute of Biology, Westlake Institute for Advanced Study, Hangzhou Zhejiang 310024, China）
Abstract Glutamate is the primary excitatory neurotransmitter in the vertebrate nervous system, initiating rapid signal transmission and playing key roles in learning, memory, and synaptic plasticity. The final, crucial step in signal transmission is the rapid clearance of released glutamate from the synaptic cleft to prevent excitotoxicity, a task predominantly carried out by the excitatory amino acid transporter 2 (EAAT2). Here, we present the inward-facing structures of human EAAT2, including the ligand-free conformation with an open HP2 gate, an inhibitor-bound open conformation, and an activator-bound closed conformation. These structures demonstrate that, following the intracellular transport of neurotransmitters, the inhibitor WAY-213613 competitively binds to the substrate binding site, locking EAAT2 in an inward-open conformation with an open HP2 loop, thereby inhibiting its reverse transport process. Conversely, the activator GT-949 appears to accelerate this process. These structural insights provide molecular details on ligand positioning and the mechanisms regulating EAAT2 activity. Overall, these structural data lay the foundation for understanding the structure-function relationship of EAAT2 and for the design of novel therapeutic modulators.
Keywords excitatory amino acid transporter；SLC1A2；neurodegenerative disease；Cryo-EM structure
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