Identification of a chloride-formate exchanger expressed on the brush border membrane of renal proximal tubule cells
| Autor: | Sue Ann Mentone, Chao Ling Yang, Peter S. Aronson, R. Brent Thomson, Gerhard Giebisch, Felix Knauf |
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| Rok vydání: | 2001 |
| Předmět: |
DNA
Complementary Brush border Molecular Sequence Data SLC26A3 4 4'-Diisothiocyanostilbene-2 2'-Disulfonic Acid Sodium-Phosphate Cotransporter Proteins Type IIa Antiporters Kidney Tubules Proximal Mice Xenopus laevis SLC26A6 Animals Amino Acid Sequence Cloning Molecular DNA Primers Oxalate transport Multidisciplinary Renal oligopeptide reabsorption Base Sequence Microvilli biology Reabsorption Pendrin Biological Sciences Apical membrane Cell biology Mice Inbred C57BL Microscopy Fluorescence Biochemistry COS Cells biology.protein Female |
| Zdroj: | Proceedings of the National Academy of Sciences. 98:9425-9430 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.141241098 |
| Popis: | A key function of the proximal tubule is retrieval of most of the vast quantities of NaCl and water filtered by the kidney. Physiological studies using brush border vesicles and perfused tubules have indicated that a major fraction of Cl − reabsorption across the apical membrane of proximal tubule cells occurs via Cl − -formate exchange. The molecular identity of the transporter responsible for renal brush border Cl − -formate exchange has yet to be elucidated. As a strategy to identify one or more anion exchangers responsible for mediating Cl − reabsorption in the proximal tubule, we screened the expressed sequence tag database for homologs of pendrin, a transporter previously shown to mediate Cl − -formate exchange. We now report the cDNA cloning of CFEX, a mouse pendrin homolog with expression in the kidney by Northern analysis. Sequence analysis indicated that CFEX very likely represents the mouse ortholog of human SLC26A6. Immunolocalization studies detected expression of CFEX, but not pendrin, on the brush border membrane of proximal tubule cells. Functional expression studies in Xenopus oocytes demonstrated that CFEX mediates Cl − -formate exchange. Taken together, these observations identify CFEX as a prime candidate to mediate Cl − -formate exchange in the proximal tubule and thereby to contribute importantly to renal NaCl reabsorption. Given its wide tissue distribution, CFEX also may contribute to transcellular Cl − transport in additional epithelia such as the pancreas and contribute to transmembrane Cl − transport in nonepithelial tissues such as the heart. |
| Databáze: | OpenAIRE |
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