Multiple transport functions of a red blood cell anion exchanger, tAE1: its role in cell volume regulation
| Autor: | R Motais, Hélène Guizouarn, Nicole Gabillat, Franck Borgese |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Erythrocytes
IBMX Membrane permeability Trout Physiology Xenopus Gene Expression Angiogenesis Inhibitors 4 4'-Diisothiocyanostilbene-2 2'-Disulfonic Acid Lithium Membrane Potentials Xenopus laevis chemistry.chemical_compound Chlorides Anion Exchange Protein 1 Erythrocyte Cations medicine Animals Cyclooxygenase Inhibitors Chloride channel activity Membrane potential biology Sodium Niflumic acid Niflumic Acid Original Articles Water-Electrolyte Balance Rubidium biology.organism_classification Cystic fibrosis transmembrane conductance regulator Cross-Linking Reagents chemistry Biochemistry Nitrobenzoates Mutagenesis Site-Directed Oocytes Potassium Biophysics biology.protein Female Cation transport medicine.drug |
| Zdroj: | The Journal of Physiology. 535:497-506 |
| ISSN: | 1469-7793 0022-3751 |
| DOI: | 10.1111/j.1469-7793.2001.t01-1-00497.x |
| Popis: | 1. It was previously shown that expressed in Xenopus oocyte the mouse (mAE1) and the trout (tAE1) anion exchanger behave differently: both elicit anion exchange activity but only tAE1 induces a transport of organic solutes correlated with a chloride channel activity. The present data, obtained by measurement of Xenopus oocyte membrane permeability and conductance, provide evidence that tAE1 also induces a large increase in Na(+) and K(+) permeability inhibited by several AE1 inhibitors. 2. This inhibition does not result from an effect on the driving force for electrodiffusion but represents a direct effect on the cation pathway. 3. As a control, expression of cystic fibrosis transmembrane conductance regulator (CFTR) having, once stimulated by 3-isobutyl-1-methylxanthine (IBMX), the same anion conductance magnitude as tAE1 did not induce any cation movement. 4. Chloride exchange, channel activity and cation transport induced by anion exchanger expression are inhibited by free or covalently bound H2DIDS as well. This covalent inhibition is reversed by the point mutation of Lys-522, the covalent binding site of H2DIDS to the protein. These data reveal that tAE1 itself acts both as an anion exchanger and as a channel of broad selectivity. 5. All results obtained by expression of AE1 isoforms in Xenopus oocytes and those obtained in erythrocytes are consistent with the proposal that, in nucleated erythrocytes, tAE1 functions as the swelling-activated osmolyte anion channel involved in cell volume regulation. In contrast AE1 from mammalian red cells, which do not regulate their volume, lacks swelling-activated osmolyte channel properties. 6. tAE1 illustrates the ability of a specific transport system to be a multifunctional protein exhibiting other transport functions when submitted to regulation. |
| Databáze: | OpenAIRE |
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