Structural characterization of the urea transporter bound to the orally bioavailable inhibitor E3.
Huang, S.M., Cai, B.Y., Liu, L., Yang, L.J., Li, Z., Zhang, C., Xiong, M.Y., Zhang, H., Li, Y.R., Huang, Z.Z., Sun, Y., Yang, B.X., Sun, J.P.(2025) Acta Pharmacol Sin 46: 2989-2997
- PubMed: 40523902 
- DOI: https://doi.org/10.1038/s41401-025-01595-7
- Primary Citation of Related Structures:  
9LHT - PubMed Abstract: 
Orally bioavailable inhibitors targeting the kidney urea transporter (UT) have the potential to serve as salt-sparing diuretics by employing a urea-selective diuretic mechanism of action distinct from that of diuretics targeting salt transporters. To elucidate the mechanism by which oral inhibitors interact with UTs, we solved the structure of a newly developed inhibitor, E3, with UT-A2 using cryo-electron microscopy. Through structural analysis and binding free energy calculations, we not only revealed the binding mode of E3 to UT-A2 but also clarified the structural basis by which E3 serves as a common competitive inhibitor of human, mouse and rat UT-A/UT-B. E3 exerts its inhibitory effect by competitively binding to the conserved Q-T-T-Q motif in the urea binding pockets of the transport channel. Moreover, we discovered that the BSBP region of UT can serve as a key region for enhancing the inhibitory potency of E3 with different UTs, which provides valuable structural insights for designing and modifying high-affinity UT inhibitors that act as diuretics.
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Beijing Key Laboratory of Cardiovascular Receptors Research, Peking University, Beijing, 100191, China. huangshenming@jnu.edu.cn.
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