title: The sodium chloride cotransporter (NCC) and epithelial sodium channel (ENaC) associate.
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.
authors.affiliation: Division of Nephrology, Department of Medicine, Emory University, 615 Michael St, rm. 601, Atlanta, GA 30322, USA.
authors.forename: Abinash C
authors.initials: AC
authors.lastname: Mistry
authors.affiliation: Division of Nephrology, Department of Medicine, Emory University, 615 Michael St, rm. 601, Atlanta, GA 30322, USA.
authors.forename: Brandi M
authors.initials: BM
authors.lastname: Wynne
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA The College of Resources and Environmental Science at Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Yu
authors.affiliation: Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
authors.forename: Viktor
authors.initials: V
authors.lastname: Tomilin
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Yue
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Otor
authors.initials: O
authors.lastname: Al-Khalili
authors.affiliation: Division of Nephrology, Department of Medicine, Emory University, 615 Michael St, rm. 601, Atlanta, GA 30322, USA.
authors.forename: Rickta
authors.initials: R
authors.lastname: Mallick
authors.affiliation: Division of Nephrology, Department of Medicine, Emory University, 615 Michael St, rm. 601, Atlanta, GA 30322, USA Department of Physiology, Emory University, Atlanta, GA 30322, USA Research Service, Atlanta Veteran's Administration Medical Center, Decatur, GA 30033, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Abdel A
authors.initials: AA
authors.lastname: Alli
authors.affiliation: Department of Medicine, University of Chicago, Chicago, IL 60637, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Ko
authors.affiliation: Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Alexa
authors.initials: A
authors.lastname: Mattheyses
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Hui-Fang
authors.initials: HF
authors.lastname: Bao
authors.affiliation: Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
authors.forename: Oleh
authors.initials: O
authors.lastname: Pochynyuk
authors.affiliation: Department of Medicine, University of Fribourg, Fribourg 1700, Switzerland.
authors.forename: Franziska
authors.initials: F
authors.lastname: Theilig
authors.affiliation: Department of Physiology, Emory University, Atlanta, GA 30322, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Eaton
authors.affiliation: Division of Nephrology, Department of Medicine, Emory University, 615 Michael St, rm. 601, Atlanta, GA 30322, USA Department of Physiology, Emory University, Atlanta, GA 30322, USA Research Service, Atlanta Veteran's Administration Medical Center, Decatur, GA 30033, USA.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Hoover
mesh_terms: D000818:Animals; D002460:Cell Line; D053503:Epithelial Sodium Channels / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D007672:Kidney Cortex / Q000378:metabolism; D051379:Mice; D018613:Microscopy, Confocal; D011485:Protein Binding; D049992:Sodium Chloride Symporters / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
chemical_list: D053503:Epithelial Sodium Channels; D049992:Sodium Chloride Symporters
keywords: ion channels; protein–protein interactions; sodium channel; sodium chloride cotransporter; transport