Special Communication SLC26A7: a basolateral Cl/HCO3 exchanger specific

SLC26A7: a basolateral Cl/HCO3 exchanger specific to intercalated cells of the outer medullary collecting duct. Am J Physiol Renal Physiol 286: F161–F169, 2004. First published September 9, 2003; 10.1152/ajprenal.00219.2003.—The outer medullary collecting duct (OMCD) plays an important role in bicarbonate reabsorption and acid-base regulation. An apical V-type H-ATPase and a basolateral Cl/HCO3 exchanger, located in intercalated cells of OMCD, medi-ate the bicarbonate reabsorption. Here we report the identification of a new basolateral Cl/HCO3 exchanger in OMCD intercalated cells in rat kidney. Northern hybridizations demonstrated the predominant expression of this transporter, also known as SLC26A7, in the outer medulla, with lower expression levels in the inner medulla. SLC26A7 was recognized as a 90-kDa band in the outer medulla by immu-noblot analysis and was localized on the basolateral membrane of a subset of OMCD cells by immunocytochemical staining. No labelin