دورية أكاديمية
Electrogenicity of Na,K- and H,K-ATPase activity and presence of a positively charged amino acid in the fifth transmembrane segment.
| العنوان: | Electrogenicity of Na,K- and H,K-ATPase activity and presence of a positively charged amino acid in the fifth transmembrane segment. |
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| المؤلفون: | Burnay, M., Crambert, G., Kharoubi-Hess, S., Geering, K., Horisberger, J.D. |
| المصدر: | Journal of Biological Chemistry, vol. 278, no. 21, pp. 19237-19244 |
| سنة النشر: | 2003 |
| المجموعة: | Université de Lausanne (UNIL): Serval - Serveur académique lausannois |
| مصطلحات موضوعية: | Animals, Bufo marinus/genetics, Cell Membrane/enzymology, Electric Conductivity, Electrochemistry, Female, Gene Expression, Lysine, Models, Molecular, Mutagenesis, Site-Directed, Oocytes/enzymology, Ouabain/pharmacology, Potassium/pharmacology, Proton-Translocating ATPases/chemistry, Proton-Translocating ATPases/genetics, Rubidium Radioisotopes/metabolism, Serine/chemistry, Sodium-Potassium-Exchanging ATPase/chemistry, Sodium-Potassium-Exchanging ATPase/genetics, Transfection, Urinary Bladder/enzymology, Xenopus |
| الوصف: | The transport activity of the Na,K-ATPase (a 3 Na+ for 2 K+ ion exchange) is electrogenic, whereas the closely related gastric and non-gastric H,K-ATPases perform electroneutral cation exchange. We have studied the role of a highly conserved serine residue in the fifth transmembrane segment of the Na,K-ATPase, which is replaced with a lysine in all known H,K-ATPases. Ouabain-sensitive 86Rb uptake and K+-activated currents were measured in Xenopus oocytes expressing the Bufo bladder H,K-ATPase or the Bufo Na,K-ATPase in which these residues, Lys800 and Ser782, respectively, were mutated. Mutants K800A and K800E of the H,K-ATPase showed K+-stimulated and ouabain-sensitive electrogenic transport. In contrast, when the positive charge was conserved (K800R), no K+-induced outward current could be measured, even though rubidium transport activity was present. Conversely, the S782R mutant of the Na,K-ATPase had non-electrogenic transport activity, whereas the S782A mutant was electrogenic. The K800S mutant of the H,K-ATPase had a more complex behavior, with electrogenic transport only in the absence of extracellular Na+. Thus, a single positively charged residue in the fifth transmembrane segment of the alpha-subunit can determine the electrogenicity and therefore the stoichiometry of cation transport by these ATPases. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| العلاقة: | info:eu-repo/semantics/altIdentifier/pmid/12637496; info:eu-repo/semantics/altIdentifier/pissn/0021-9258; https://serval.unil.ch/notice/serval:BIB_1A567FCF06E0Test |
| DOI: | 10.1074/jbc.M300946200 |
| الإتاحة: | https://doi.org/10.1074/jbc.M300946200Test https://serval.unil.ch/notice/serval:BIB_1A567FCF06E0Test |
| رقم الانضمام: | edsbas.478CB931 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1074/jbc.M300946200 |
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