Human ATP1AL1 gene encodes a ouabain-sensitive H-K-ATPase
| Autor: | Bernard C. Rossier, N. N. Modyanov, Käthi Geering, P. M. Mathews, Ahmed T. Beggah, A. V. Grishin, Jean-Daniel Horisberger, Pascal Béguin |
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| Rok vydání: | 1995 |
| Předmět: |
Physiology
ATPase Biology H(+)-K(+)-Exchanging ATPase Ouabain Gene product Xenopus laevis Complementary DNA Gene expression medicine Gene family Animals Humans Gene Imidazoles Biological Transport Cell Biology Molecular biology Biochemistry Genes biology.protein Oocytes Potassium Rabbits medicine.drug |
| Zdroj: | The American journal of physiology. 269(4 Pt 1) |
| ISSN: | 0002-9513 |
| Popis: | The cDNA for ATP1AL1, the fifth member of the human Na-K-adenosinetriphosphatase (ATPase)/H-K-ATPase gene family, was recently cloned (A. V. Grishin, V. E. Sverdlov, M. B. Kostina, and N. N. Modyanov. FEBS Lett. 349: 144-150, 1994). The encoded protein (ATP1AL1) has all the primary structural features common to the catalytic alpha-subunit of ion-transporting P-type ATPases and is similar (63-64% identity) to the Na-K-ATPase alpha-subunit isoforms and the gastric H-K-ATPase alpha-subunit. In this study, ATP1AL1 was expressed in Xenopus laevis oocytes in combination with the beta-subunit of rabbit gastric H-K-ATPase. The functional properties of the stable alpha/beta-complex were studied by 86Rb+ uptake and demonstrated that ATP1AL1 is a novel human K(+)-dependent ATPase [apparent half-constant activation/(K1/2) for K+ approximately 375 microM)]. ATP1AL1-mediated inward K+ transport was inhibited by ouabain (inhibition constant approximately 13 microM) and was found to be inhibited by high concentrations of SCH-28080 (approximately 70% at 500 microM). ATP1AL1 expression resulted in the alkalinization of the oocytes' cytoplasm and ouabain-sensitive proton extrusion, as measured with pH-sensitive microelectrodes. These data argue that ATP1AL1 is the catalytic alpha-subunit of a human nongastric P-type ATPase capable of exchanging extracellular potassium for intracellular protons. |
| Databáze: | OpenAIRE |
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