Physiology of Electrogenic SLC26 Paralogues

Michael F Romero, Min Hwang Chang, Consuelo Plata, Kambiz Zandi-Nejad, Adriana Mercado, Vadjista Broumand, Caroline R. Sussman, David B. Mount

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Scopus citations

Abstract

SLC26 anion exchangers transport monovalent and divalent anions, with a diversity of anion specificity and stoichiometry. Our microelectrode studies indicate that several SLC26 members are electrogenic. We reported that Slc26a6 functions as a Cl-/formate, Cl-/oxalate, Cl-/OH- and electrogenic Cl-/nHCO3- exchanger. Recently, we have also confirmed that Slc26a7 does not behave as a Cl-/HCO3- exchanger but does function as an electrogenic anion conductance, perhaps a channel. We have also cloned murine Slc26a9, which is strongly expressed in the respiratory tract and stomach. Radioisotope uptakes in Xenopus oocytes indicate that Slc26a9 is a highly selective anion exchanger, transporting Cl- but neither formate, oxalate, nor SO42-. We also utilized electrophysiology to voltage clamp (VC) and/or measure intracellular pH (pHi), Cl- ([Cl-]i) and Na+ ([Na+]i), in response to various ion replacements. Cl- removal in HCO3- depolarizes oocytes (to > +60mV), alkalinizes oocytes, and decreases aCli-. Slc26a9 thus functions as an electrogenic nCl-/HCO3- exchanger, suggesting a role in pulmonary and gastric HCO3- secretion and/or CO2 transport. VC experiments revealed channel-like currents (>10μA at -60mV and >80μA at +60mV) mediated by Slc26a9 in the presence and absence of HCO3-. Our experiments and those of others continue to reveal additional characteristics and unique roles for this new class of electrogenic anion transporters.

Original languageEnglish (US)
Title of host publicationEpithelial Anion Transport in Health and Disease: The Role of the SLC26 Transporters Family
PublisherWiley Blackwell
Pages126-138
Number of pages13
ISBN (Print)9780470029572, 0470016248, 9780470016244
DOIs
StatePublished - Oct 7 2008
Externally publishedYes

Keywords

  • Cl- channel
  • Electrophysiology
  • Epithelia
  • HCO3- transport
  • Microelectrodes
  • Voltage clamp

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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  • Cite this

    Romero, M. F., Chang, M. H., Plata, C., Zandi-Nejad, K., Mercado, A., Broumand, V., Sussman, C. R., & Mount, D. B. (2008). Physiology of Electrogenic SLC26 Paralogues. In Epithelial Anion Transport in Health and Disease: The Role of the SLC26 Transporters Family (pp. 126-138). Wiley Blackwell. https://doi.org/10.1002/0470029579.ch9