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XB-ART-34937
Novartis Found Symp. January 1, 2006; 273 Physiology of electrogenic SLC26 paralogues.
Romero MF
,
Chang MH
,
Plata C
,
Zandi-Nejad K
,
Mercado A
,
Broumand V
,
Sussman CR
,
Mount DB
.
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-],) and Na+ ([Na+]i), in response to various ion replacements. Cl- removal in HCO3- depolarizes oocytes (to > +60mV), alkalinizes oocytes, and decreases aCl-i. 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 (>10 microA at -60mV and >80 microA 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.Pubmed Id: 17120765 Article link:Grant support:
DK-56218 NIDDK NIH HHS , DK-60845 NIDDK NIH HHS , DK038226 NIDDK NIH HHS , DK57708 NIDDK NIH HHS Genes referenced: eif3a ncl slc26a6 slc26a7 slc26a9 Antibodies referenced: |
[2.8.5]
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