Structure of the Human Cation-chloride Cotransporter NKCC1 Determined by Single-particle Electron Cryo-microscopy

Overview

Journal Nat Commun

Specialty Biology

Date 2020 Feb 22

PMID 32081947

Citations 35

Authors

Xiaoyong Yang

Qinzhe Wang

Erhu Cao

Affiliations

Soon will be listed here.

Abstract

The secondary active cation-chloride cotransporters (CCCs) utilize the existing Na and/or K gradients to move Cl into or out of cells. NKCC1 is an intensively studied member of the CCC family and plays fundamental roles in regulating trans-epithelial ion movement, cell volume, chloride homeostasis and neuronal excitability. Here, we report a cryo-EM structure of human NKCC1 captured in a partially loaded, inward-open state. NKCC1 assembles into a dimer, with the first ten transmembrane (TM) helices harboring the transport core and TM11-TM12 helices lining the dimer interface. TM1 and TM6 helices break α-helical geometry halfway across the lipid bilayer where ion binding sites are organized around these discontinuous regions. NKCC1 may harbor multiple extracellular entryways and intracellular exits, raising the possibility that K, Na, and Cl ions may traverse along their own routes for translocation. NKCC1 structure provides a blueprint for further probing structure-function relationships of NKCC1 and other CCCs.

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References

Gamba G . Molecular physiology and pathophysiology of electroneutral cation-chloride cotransporters. Physiol Rev. 2005; 85(2):423-93. DOI: 10.1152/physrev.00011.2004. View

Russell J . Sodium-potassium-chloride cotransport. Physiol Rev. 2000; 80(1):211-76. DOI: 10.1152/physrev.2000.80.1.211. View

Payne J . Molecular operation of the cation chloride cotransporters: ion binding and inhibitor interaction. Curr Top Membr. 2012; 70:215-37. DOI: 10.1016/B978-0-12-394316-3.00006-5. View

Lauf P, Bauer J, Adragna N, Fujise H, ZADE-OPPEN A, Ryu K . Erythrocyte K-Cl cotransport: properties and regulation. Am J Physiol. 1992; 263(5 Pt 1):C917-32. DOI: 10.1152/ajpcell.1992.263.5.C917. View

Delpire E, Gagnon K . Na -K -2Cl Cotransporter (NKCC) Physiological Function in Nonpolarized Cells and Transporting Epithelia. Compr Physiol. 2018; 8(2):871-901. DOI: 10.1002/cphy.c170018. View

Ben-Ari Y . NKCC1 Chloride Importer Antagonists Attenuate Many Neurological and Psychiatric Disorders. Trends Neurosci. 2017; 40(9):536-554. DOI: 10.1016/j.tins.2017.07.001. View

Delpire E, Staley K . Novel determinants of the neuronal Cl(-) concentration. J Physiol. 2014; 592(19):4099-114. PMC: 4215762. DOI: 10.1113/jphysiol.2014.275529. View

Dzhala V, Talos D, Sdrulla D, Brumback A, Mathews G, Benke T . NKCC1 transporter facilitates seizures in the developing brain. Nat Med. 2005; 11(11):1205-13. DOI: 10.1038/nm1301. View

Blaesse P, Airaksinen M, Rivera C, Kaila K . Cation-chloride cotransporters and neuronal function. Neuron. 2009; 61(6):820-38. DOI: 10.1016/j.neuron.2009.03.003. View

10.

Brumback A, Staley K . Thermodynamic regulation of NKCC1-mediated Cl- cotransport underlies plasticity of GABA(A) signaling in neonatal neurons. J Neurosci. 2008; 28(6):1301-12. PMC: 6671583. DOI: 10.1523/JNEUROSCI.3378-07.2008. View

11.

Simon D, Bia M, Ellison D, Karet F, Molina A, Vaara I . Gitelman's variant of Bartter's syndrome, inherited hypokalaemic alkalosis, is caused by mutations in the thiazide-sensitive Na-Cl cotransporter. Nat Genet. 1996; 12(1):24-30. DOI: 10.1038/ng0196-24. View

12.

Simon D, Karet F, Hamdan J, Dipietro A, Sanjad S, Lifton R . Bartter's syndrome, hypokalaemic alkalosis with hypercalciuria, is caused by mutations in the Na-K-2Cl cotransporter NKCC2. Nat Genet. 1996; 13(2):183-8. DOI: 10.1038/ng0696-183. View

13.

Ji W, Foo J, ORoak B, Zhao H, Larson M, Simon D . Rare independent mutations in renal salt handling genes contribute to blood pressure variation. Nat Genet. 2008; 40(5):592-599. PMC: 3766631. DOI: 10.1038/ng.118. View

14.

Boyden L, Choi M, Choate K, Nelson-Williams C, Farhi A, Toka H . Mutations in kelch-like 3 and cullin 3 cause hypertension and electrolyte abnormalities. Nature. 2012; 482(7383):98-102. PMC: 3278668. DOI: 10.1038/nature10814. View

15.

WILSON F, Choate K, Ishikawa K, Desitter I, Gunel M, Milford D . Human hypertension caused by mutations in WNK kinases. Science. 2001; 293(5532):1107-12. DOI: 10.1126/science.1062844. View

16.

Kahle K, Ring A, Lifton R . Molecular physiology of the WNK kinases. Annu Rev Physiol. 2007; 70:329-55. DOI: 10.1146/annurev.physiol.70.113006.100651. View

17.

Malha L, Mann S . Loop Diuretics in the Treatment of Hypertension. Curr Hypertens Rep. 2016; 18(4):27. DOI: 10.1007/s11906-016-0636-7. View

18.

Sinha A, Agarwal R . Thiazide Diuretics in Chronic Kidney Disease. Curr Hypertens Rep. 2015; 17(3):13. DOI: 10.1007/s11906-014-0525-x. View

19.

Bai X, Moraes T, Reithmeier R . Structural biology of solute carrier (SLC) membrane transport proteins. Mol Membr Biol. 2018; 34(1-2):1-32. DOI: 10.1080/09687688.2018.1448123. View

20.

Drew D, Boudker O . Shared Molecular Mechanisms of Membrane Transporters. Annu Rev Biochem. 2016; 85:543-72. DOI: 10.1146/annurev-biochem-060815-014520. View