The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate

• Type of Material: Article
• Authors: Abinash Mistry, Emory University; Brandi Wynne, Emory University; Ling Yu, Emory University; Victor Tomilin, Russian Academy of Sciences; Qiang Yue, Emory University; Yiqun Zhou, Emory University; Otor Al-Khalili, Emory University; Rickta Mallick, Emory University; Hui Cai, Emory University; Abdel Alli, Emory University; Benjamin Ko, University of Chicago; Hui-Fang Bao, Emory University; Alexa Mattheyses, Emory University; Oleh Pochynyuk, University of Texas Health Science Center at Houston; Franziska Theilig, University of Fribourg; Douglas Eaton, Emory University; Robert Hoover Jr, Emory University
• Language: English
• Date: 2016-09-27
• Publisher: Portland Press
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.
• Final Published Version (URL): http://dx.doi.org/10.1042/BCJ20160312
• Title of Journal or Parent Work: Biochemical Journal
• ISSN: 0264-6021
• Volume: 473
• Issue: 19
• Start Page: 3237
• End Page: 3252
• Grant/Funding Information: This research project was also supported in part by the Emory University Integrated Cellular Imaging Microscopy Core of the Emory University Department of Physiology.; Also by Department of Veteran Affairs VA Merit Awards I01BX002322-01 (R.S.H.) and I01BX000994 (H.C.).; Also the Swiss National Foundation (F.T.), AHA GIA 13GRNT16220002 (O.P.), and the Russian Foundation for Basic Research #15-04-00938.; This work was supported by grants from the National Institutes of Health R01 DK-085097 (to R.S.H.), T32 DK07656 (B.M.W.), 1K01DK099617 (A.A.A.), R37 DK037963 (D.C.E.) and RO1 DK095029 (O.P.).
• Keywords: TRANSPORT PATHWAYS; BLOOD-PRESSURE; DISTAL CONVOLUTED TUBULE; MINERALOCORTICOID RECEPTORS; BARTTERS-SYNDROME; Life Sciences & Biomedicine; Science & Technology; NA-CL COTRANSPORTER; EXPRESSION; Biochemistry & Molecular Biology; STAS DOMAIN; PROTEIN; KNOCKOUT MICE
• Research Categories: Biology, Cell; Biology, Physiology

Abstract

The thiazide-sensitive sodium chloride cotransporter (NCC) and the epithelial sodium channel (ENaC) are two of the most important determinants of salt balance and thus systemic blood pressure. Abnormalities in either result in profound changes in blood pressure. There is one segment of the nephron where these two sodium transporters are coexpressed, the second part of the distal convoluted tubule. This is a key part of the aldosterone-sensitive distal nephron, the final regulator of salt handling in the kidney. Aldosterone is the key hormonal regulator for both of these proteins. Despite these shared regulators and coexpression in a key nephron segment, associations between these proteins have not been investigated. After confirming apical localization of these proteins, we demonstrated the presence of functional transport proteins and native association by blue native PAGE. Extensive coimmunoprecipitation experiments demonstrated a consistent interaction of NCC with α-And γ-ENaC. Mammalian two-hybrid studies demonstrated direct binding of NCC to ENaC subunits. Fluorescence resonance energy transfer and immunogold EM studies confirmed that these transport proteins are within appropriate proximity for direct binding. Additionally, we demonstrate that there are functional consequences of this interaction, with inhibition of NCC affecting the function of ENaC. This novel finding of an association between ENaC and NCC could alter our understanding of salt transport in the distal tubule.