The Heterotetrameric Architecture of the Epithelial Sodium Channel (ENaC)

Overview

Journal EMBO J

Specialties Biotechnology
Molecular Biology

Date 1998 Feb 28

PMID 9430626

Citations 93

Authors

D Firsov

I Gautschi

A M Merillat

B C Rossier

L Schild

Affiliations

Soon will be listed here.

Abstract

The epithelial sodium channel (ENaC) is a key element for the maintenance of sodium balance and the regulation of blood pressure. Three homologous ENaC subunits (alpha, beta and gamma) assemble to form a highly Na+-selective channel. However, the subunit stoichiometry of ENaC has not yet been solved. Quantitative analysis of cell surface expression of ENaC alpha, beta and gamma subunits shows that they assemble according to a fixed stoichiometry, with alpha ENaC as the most abundant subunit. Functional assays based on differential sensitivities to channel blockers elicited by mutations tagging each alpha, beta and gamma subunit are consistent with a four subunit stoichiometry composed of two alpha, one beta and one gamma. Expression of concatameric cDNA constructs made of different combinations of ENaC subunits confirmed the four subunit channel stoichiometry and showed that the arrangement of the subunits around the channel pore consists of two alpha subunits separated by beta and gamma subunits.

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