Na+/H+ antiporters, molecular devices that couple the Na+ and H+ circulation in cells.
Na+/H+ antiporters are universal devices involved in the Na+ and H+ circulation of both eukaryotes and prokaryotes, thus playing an essential role in the pH and Na+ homeostasis of cells. This review focuses on the major impact of the application of molecular biology tools in the study of the antiporters. These tools permit the verification of the role of the antiporters and provide insights into their unique biology. A novel signal transduction to Na+ involving nhaR, a positive regulator, controls the expression of nhaA in E. coli. A "pH sensor" regulates the activity of Na+/H+ antiporters, both in eukaryotes and prokaryotes. A most intricate signal transduction to pH involving phosphorylation steps controls the activity of nhel in higher mammals. The identification of Histidine 226 in the "pH sensor" of NhaA is a step forward towards the understanding of the pH regulation of these proteins.
Padan
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Division of Microbial and Molecular Ecology, Hebrew University of Jerusalem, Israel.
Schuldiner
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D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D006706:Homeostasis; D006863:Hydrogen-Ion Concentration; D008322:Mammals; D015398:Signal Transduction; D012964:Sodium / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D014157:Transcription Factors / Q000096:biosynthesis / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D017923:Sodium-Hydrogen Exchangers; D014157:Transcription Factors; C074687:nhaR protein, E coli; D012964:Sodium