Structure of the human cation-chloride cotransport KCC1 in an outward-open state.
Structure of the human cation-chloride cotransport KCC1 in an outward-open state.
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DOI：
10.1073/pnas.2109083119
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发表时间：
2022-07-05
影响因子：
11.1
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中科院分区：
文献类型：
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阳离子-氯化物协同转运蛋白（CCCs）负责Na+、K+和Cl−的跨膜转运。然而，目前尚不清楚CCC如何在运输状态之间交替，以便它们可以从膜的一侧加载离子以释放到另一侧。此外，CCC被用作治疗高血压/水肿的临床药物或用作解剖CCC功能的药理学工具的化合物靶向。这些药物如何与CCC相互作用尚未阐明。我们的K+-Cl−协同转运蛋白（KCC）1与VU 0463271抑制剂结合的结构突出了细胞外离子转运途径作为开发CCC调节剂的有希望的位点，并定义了KCC 1中离子转运的关键构象变化，这与在相关转运蛋白表兄弟中观察到的构象变化不同。阳离子-氯化物协同转运蛋白（CCCs）催化Cl−与Na+和/或K+跨膜的电中性同向转运。CCCs在细胞体积稳态、跨上皮离子运动、维持细胞内Cl−浓度和神经元兴奋性中起重要作用。在这里，我们提出了一个冷冻电子显微镜结构的人K+-Cl−协同转运蛋白（KCC）1与VU 0463271抑制剂结合在一个向外开放的状态。与许多其他氨基酸-多胺-有机体转运蛋白表兄弟相比，我们的第一个向外开放的CCC结构揭示了打开KCC 1细胞外离子渗透路径不涉及跨膜（TM）1和TM 6半螺旋的铰链弯曲运动。相反，TM 3和TM 8的摇摆，连同TM 4、TM 9和保守的胞内环1螺旋的位移，是细胞外和细胞质前庭交替打开和关闭的基础。我们发现，KCC 1有趣地存在于两个不同的二聚体状态之一，通过不同的亚基间接口。我们的研究为理解CCC的机制及其小分子化合物的抑制作用提供了蓝图。
Cation–chloride cotransporters (CCCs) shuttle Na+, K+, and Cl− across membranes. However, it remains unclear how CCCs alternate between transport states so they can load ions from one side of a membrane for release into the other side. Moreover, CCCs are targeted by compounds that are used as clinical medicines for treating hypertension/edema or as pharmacological tools for dissecting CCC functions. How these pharmacological agents interact with CCCs is yet to be elucidated. Our structure of K+–Cl− cotransporter (KCC) 1 bound with the VU0463271 inhibitor highlights the extracellular ion translocation pathway as a promising site for developing CCC modulators and defines conformational changes critical for ion transport in KCC1, which are distinct from those observed in related transporter cousins. Cation–chloride cotransporters (CCCs) catalyze electroneutral symport of Cl− with Na+ and/or K+ across membranes. CCCs are fundamental in cell volume homeostasis, transepithelia ion movement, maintenance of intracellular Cl− concentration, and neuronal excitability. Here, we present a cryoelectron microscopy structure of human K+–Cl− cotransporter (KCC)1 bound with the VU0463271 inhibitor in an outward-open state. In contrast to many other amino acid–polyamine–organocation transporter cousins, our first outward-open CCC structure reveals that opening the KCC1 extracellular ion permeation path does not involve hinge-bending motions of the transmembrane (TM) 1 and TM6 half-helices. Instead, rocking of TM3 and TM8, together with displacements of TM4, TM9, and a conserved intracellular loop 1 helix, underlie alternate opening and closing of extracellular and cytoplasmic vestibules. We show that KCC1 intriguingly exists in one of two distinct dimeric states via different intersubunit interfaces. Our studies provide a blueprint for understanding the mechanisms of CCCs and their inhibition by small molecule compounds.
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影响因子：
82.9
作者：
通讯作者：
--
影响因子：
64.8
作者：
Coleman, Jonathan A.;Yang, Dongxue;Gouaux, Eric
通讯作者：
Gouaux, Eric
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH
影响因子：
14.8
作者：
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影响因子：
4.4
作者：
JORGENSEN, WL;CHANDRASEKHAR, J;KLEIN, ML
通讯作者：
KLEIN, ML