Molecular characteristics and physiological roles of Na+–K+–Cl− cotransporter 2

• Published in: Journal of cellular physiology 2021-03, Vol.236 (3), p.1712-1729
• Main Authors: Marcoux, Andree‐Anne, Tremblay, Laurence E., Slimani, Samira, Fiola, Marie‐Jeanne, Mac‐Way, Fabrice, Garneau, Alexandre P., Isenring, Paul
• Format: Article
• Language: English
• Subjects: Abnormalities; Alternative splicing; Alternative Splicing - genetics; Amino Acid Sequence; Animals; Bartter syndrome; Calcium; Calcium ions; cation‐Cl− cotransporter; Diuretics; Hereditary diseases; high blood pressure; Humans; Inactivation; Ion Transport; Loop of Henle; Loop of Henle - metabolism; Magnesium; Membrane proteins; Membranes; Models, Biological; Na+–K+–Cl− cotransporter 2; Physiology; renal physiology; Review; Sodium; Solute Carrier Family 12, Member 3 - chemistry; Solute Carrier Family 12, Member 3 - genetics; Solute Carrier Family 12, Member 3 - metabolism; Transportation systems
• ISSN: 0021-9541; 1097-4652; 1097-4652
• DOI: 10.1002/jcp.29997

Na+–K+–Cl− cotransporter 2 (NKCC2; SLC12A1) is an integral membrane protein that comes as three splice variants and mediates the cotranslocation of Na+, K+, and Cl− ions through the apical membrane of the thick ascending loop of Henle (TALH). In doing so, and through the involvement of other ion transport systems, it allows this nephron segment to reclaim a large fraction of the ultrafiltered Na+, Cl−, Ca2+, Mg2+, and HCO3− loads. The functional relevance of NKCC2 in human is illustrated by the many abnormalities that result from the inactivation of this transport system through the use of loop diuretics or in the setting of inherited disorders. The following presentation aims at discussing the physiological roles and molecular characteristics of Na+–K+–Cl− cotransport in the TALH and those of the individual NKCC2 splice variants more specifically. Many of the historical and recent data that have emerged from the experiments conducted will be outlined and their larger meaning will also be placed into perspective with the aid of various hypotheses. Na+–K+–Cl− cotransporter 2 (NKCC2) mediates the cotranslocation of Na+, K+, and Cl− ions through the apical membrane of the thick ascending loop of Henle (TALH). In doing so, it allows this nephron segment to reclaim a large fraction of the ultrafiltered Na+, Cl−, Ca2+, Mg2+, and HCO3− load. The functional relevance of NKCC2 in humans is illustrated by the many abnormalities that result from the inactivation of this transport system.