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 proceedingConference contribution

25 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-/nHCO 3- 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 (pH i), Cl- ([Cl-]i) and Na+ ([Na+]i), in response to various ion replacements. Cl - removal in HCO3- depolarizes oocytes (to > +60 mV), alkalinizes oocytes, and decreases aCli-. Slc26a9 thus functions as an electrogenic nCl-/HCO3 - exchanger, suggesting a role in pulmonary and gastric HCO 3- secretion and/or CO2 transport. VC experiments revealed channel-like currents (>10 μA at -60 mV and >80 μA at +60 mV) mediated by Slc26a9 in the presence and absence of HCO 3-. 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
Subtitle of host publicationThe Role of the SLC26 Transporters Family
Pages126-138
Number of pages13
StatePublished - 2006

Publication series

NameNovartis Foundation Symposium
Volume273
ISSN (Print)1528-2511

ASJC Scopus subject areas

  • Medicine(all)

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