Book chapter
Chapter 2 Membrane Topology, Subunit Composition, and Stoichiometry of the Epithelial Na+Channel
Current Topics in Membranes, pp.25-36
Elsevier Science & Technology
1999
DOI: 10.1016/S0070-2161(08)60950-8
Abstract
The chapter presents a review of the membrane topology, subunit composition, and stoichiometry of epithelial Na+ channel (ENaC). To begin to define the structure of ENaC, the chapter mentions the membrane topology of the rat a subunit (αrENaC). In vitro translation of αrENaC produced a 73-kDa protein, and an additional 93-kDa protein was produced when αrENaC was translated in the presence of microsomal membranes, corresponding to the core-glycosylated form of the protein. Three ENaC subunits have been identified in epithelia of rat and human: α, β, and γENaC. It is found that expression of the human, a subunit alone in Xenopus oocytes, produced amiloride-sensitive Na+ current. The finding that coexpression of α, β, and γENaC is required for maximal Na+ current suggests that ENaC is a heteromultimeric channel. Genetic evidence from C. elegans suggests that the degenerins also function as heteromultimers. A biochemical assay is used to determine whether the mass of hENaC was consistent with a complex containing nine subunits. Because αhENaC can form a functional channel by itself, the mass of in vitro is determined, expressed α by sucrose gradient sedimentation.
Details
- Title: Subtitle
- Chapter 2 Membrane Topology, Subunit Composition, and Stoichiometry of the Epithelial Na+Channel
- Creators
- Peter M Snyder - University of IowaChun Cheng - University of IowaMichael J Welsh - University of Iowa
- Resource Type
- Book chapter
- Publication Details
- Current Topics in Membranes, pp.25-36
- Publisher
- Elsevier Science & Technology
- DOI
- 10.1016/S0070-2161(08)60950-8
- ISSN
- 1063-5823
- Language
- English
- Date published
- 1999
- Academic Unit
- Cardiovascular Medicine; Fraternal Order of Eagles Diabetes Research Center; Internal Medicine; Medicine Administration; Neurology; Pulmonary, Critical Care, and Occupational Medicine; Molecular Physiology and Biophysics; Neurosurgery
- Record Identifier
- 9984259504702771
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