Structural basis of GABA reuptake inhibition.
Structural basis of GABA reuptake inhibition.
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DOI：
10.1038/s41586-022-04814-x
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发表时间：
2022-06
期刊：
影响因子：
64.8
通讯作者：
中科院分区：
文献类型：
--
作者：
γ-氨基丁酸 (GABA) 转运蛋白 1 (GAT1) 通过清除突触小泡释放的抑制性神经递质 GABA 的突触间隙来调节中枢神经系统的神经元兴奋。通过抑制 GABA 再摄取转运蛋白来提高突触间隙中的 GABA 水平，是治疗癫痫等神经系统疾病的既定策略。在这里，我们确定了全长野生型人 GAT1 与其临床使用的抑制剂噻加宾复合物的冷冻电镜结构，其有序部分仅为 60 kDa。我们的结构表明，噻加宾通过阻断 GABA 释放途径的细胞内门，将 GAT1 锁定在向内开放的构象中，从而抑制神经递质的摄取。我们的结果提供了对噻加宾（一种重要的抗惊厥药物）对 GAT1 的混合型抑制的见解。我们的实验数据证实了其药效学特征，表明噻加宾最初以向外开放构象与底物结合位点结合，而我们的结构表明药物以向内开放构象阻碍转运蛋白，这与两步抑制机制一致。 GAT1 的呈现结构为这种重要的神经递质转运蛋白的生物学和药理学提供了重要的见解，并为神经调节剂的合理设计提供了蓝图，并突破了单颗粒冷冻电子显微镜中具有挑战性的膜蛋白的可能界限。
γ-Aminobutyric acid (GABA) transporter 1 (GAT1) regulates neuronal excitation of the central nervous system by clearing the synaptic cleft of the inhibitory neurotransmitter GABA upon its release from synaptic vesicles. Elevating the levels of GABA in the synaptic cleft, by inhibiting GABA reuptake transporters, is an established strategy to treat neurological disorders, such as epilepsy. Here we determined the cryo-electron microscopy structure of full-length, wild-type human GAT1 in complex with its clinically used inhibitor tiagabine, with an ordered part of only 60 kDa. Our structure reveals that tiagabine locks GAT1 in the inward-open conformation, by blocking the intracellular gate of the GABA release pathway, and thus suppresses neurotransmitter uptake. Our results provide insights into the mixed-type inhibition of GAT1 by tiagabine, which is an important anticonvulsant medication. Its pharmacodynamic profile, confirmed by our experimental data, suggests initial binding of tiagabine to the substrate-binding site in the outward-open conformation, whereas our structure presents the drug stalling the transporter in the inward-open conformation, consistent with a two-step mechanism of inhibition. The presented structure of GAT1 gives crucial insights into the biology and pharmacology of this important neurotransmitter transporter and provides blueprints for the rational design of neuromodulators, as well as moving the boundaries of what is considered possible in single-particle cryo-electron microscopy of challenging membrane proteins.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
Coleman, Jonathan A.;Yang, Dongxue;Gouaux, Eric
通讯作者：
Gouaux, Eric
影响因子：
4.4
作者：
Rudnick G
通讯作者：
Rudnick G
影响因子：
56.9
作者：
GUASTELLA, J;NELSON, N;KANNER, BI
通讯作者：
KANNER, BI
影响因子：
5.3
作者：
Carpenter, LL;Schecter, JM;Price, LH
通讯作者：
Price, LH