2. Academic Validation
  3. Structural basis for human NKCC1 inhibition by loop diuretic drugs

Structural basis for human NKCC1 inhibition by loop diuretic drugs

  • EMBO J. 2025 Mar;44(5):1540-1562. doi: 10.1038/s44318-025-00368-6.
Yongxiang Zhao 1 2,  Pietro Vidossich 3,  Biff Forbush 4,  Junfeng Ma 5,  Jesse Rinehart 4 6,  Marco De Vivo 3,  Erhu Cao 7
Affiliations

Affiliations

  • 1 Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA.
  • 2 Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071, Wuhan, P. R. China.
  • 3 Laboratory of Molecular Modelling & Drug Discovery, Istituto Italiano di Tecnologia, Genoa, Via Morego 30, 16163, Italy.
  • 4 Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.
  • 5 Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington DC, 20057, USA.
  • 6 Systems Biology Institute, Yale University, West Haven, CT, USA.
  • 7 Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA. erhu.cao@biochem.utah.edu.
PMID: 39875725 DOI: 10.1038/s44318-025-00368-6
Abstract

Na+-K+-Cl- cotransporters functions as an anion importers, regulating trans-epithelial chloride secretion, cell volume, and renal salt reabsorption. Loop diuretics, including furosemide, bumetanide, and torsemide, antagonize both NKCC1 and NKCC2, and are first-line medicines for the treatment of edema and hypertension. NKCC1 activation by the molecular crowding sensing WNK kinases is critical if cells are to combat shrinkage during hypertonic stress; however, how phosphorylation accelerates NKCC1 ion transport remains unclear. Here, we present co-structures of phospho-activated NKCC1 bound with furosemide, bumetanide, or torsemide showing that furosemide and bumetanide utilize a carboxyl group to coordinate and co-occlude a K+, whereas torsemide encroaches and expels the K+ from the site. We also found that an amino-terminal segment of NKCC1, once phosphorylated, interacts with the carboxyl-terminal domain, and together, they engage with intracellular ion exit and appear to be poised to facilitate rapid ion translocation. Together, these findings enhance our understanding of NKCC-mediated epithelial ion transport and the molecular mechanisms of its inhibition by loop diuretics.

Keywords

ATP Regulatory Site; Loop Diuretics; Na+–K+–Cl− Cotransporter; With-no-lysine Kinase.

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