Anion exchangers in flux: functional differences between human and mouse SLC26A6 polypeptides
Seth L Alper1, Andrew K Stewart, Marina N Chernova
1Molecular and Vascular Medicine and Renal Units, Beth Israel Deaconess Medical Center, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.
Novartis Foundation Symposium
|November 24, 2006
Summary
Mouse and human SLC26A6 anion transporters show significant functional differences, particularly in chloride and sulfate transport. These variations impact anion exchange mechanisms and highlight the importance of orthologue-specific studies.
Area of Science:
- Molecular Biology
- Biochemistry
- Physiology
Background:
- SLC26 anion transporters display significant sequence diversity among orthologues.
- SLC26A6 orthologues show marked sequence variation, prompting functional investigation.
Purpose of the Study:
- To conduct a systematic functional comparison of mouse Slc26a6 and human SLC26A6 variants.
- To elucidate differences in transport mechanisms and properties between orthologous SLC26A6 proteins.
Main Methods:
- Xenopus oocyte expression system.
- Isotopic flux assays for oxalate, chloride (36Cl-), and sulfate (35S-).
- Electrophysiological measurements and chimera studies.
Main Results:
- Mouse Slc26a6 exhibited higher 36Cl- and 35S-sulfate transport than human SLC26A6.
- Mouse Slc26a6 mediated electrogenic Cl-/oxalate exchange, while human SLC26A6 mediated electroneutral exchange.
- Human SLC26A6 variants SLC26A6c and SLC26A6d were inactive in flux assays.
Conclusions:
- Substantial functional differences exist between mouse Slc26a6 and human SLC26A6 orthologues.
- Understanding SLC26 transport requires recognizing orthologue-specific transport properties.
- These differences are crucial for comprehending SLC26 transporter function and associated pathophysiology.
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