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Basolateral localization of flounder Na+-dicarboxylate cotransporter (fNaDC-3) in the kidney of Pleuronectes americanus.
- Source :
-
Pflugers Archiv : European journal of physiology [Pflugers Arch] 2003 Aug; Vol. 446 (5), pp. 578-84. Date of Electronic Publication: 2003 May 21. - Publication Year :
- 2003
-
Abstract
- The purpose of this study was to provide functional and immunocytochemical evidence for the location of the winter flounder ( Pleuronectes americanus) sodium-dicarboxylate cotransporter-3 (fNaDC-3) in the basolateral membrane of proximal tubule cells. fNaDC-3 was expressed in Xenopus laevis oocytes. Lowering the external pH from 7.5 to 6.5 or 5.5 modestly decreased the uptake of [(14)C]succinate into fNaDC-3 expressing oocytes, but markedly increased the uptake of [(14)C]citrate. As measured by the two-electrode voltage-clamp technique, the citrate concentration eliciting half-maximal current, K(0.5), decreased from 490 microM at pH 7.5 to 32 microM at pH 6.0. The maximal inwards current, Delta I(max), increased from -27 to -72 nA, when bath pH was changed from 7.5 to 6.0. These data suggest that fNaDC-3 translocates preferably divalent citrate. cis-Aconitate, a tricarboxylate that interacts exclusively with basolateral sodium-dicarboxylate cotransport in the rat kidney, was translocated by fNaDC-3 with a K(0.5) of 300 microM. Antibodies raised against an NaDC-3-specific peptide reacted with the basal cell side of flounder renal proximal tubule segment II (PII). No other structures were stained, indicating that fNaDC-3 is located exclusively in the basolateral membrane of PII cells. We assume that fNaDC-3 provides PII cells with Krebs cycle intermediates as fuels and with alpha-ketoglutarate to drive organic anion secretion.
- Subjects :
- Aconitic Acid metabolism
Animals
Cell Polarity physiology
Citric Acid metabolism
Flounder
Hydrogen-Ion Concentration
Immunohistochemistry
Kidney Tubules, Proximal cytology
Oocytes physiology
Patch-Clamp Techniques
Succinic Acid metabolism
Xenopus laevis
Dicarboxylic Acid Transporters metabolism
Fish Proteins metabolism
Kidney Tubules, Proximal metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0031-6768
- Volume :
- 446
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Pflugers Archiv : European journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 12759753
- Full Text :
- https://doi.org/10.1007/s00424-003-1081-4