First Author | Pajor AM | Year | 1996 |
Journal | Am J Physiol | Volume | 270 |
Issue | 4 Pt 2 | Pages | F642-8 |
PubMed ID | 8967342 | Mgi Jnum | J:32698 |
Mgi Id | MGI:80186 | Doi | 10.1152/ajprenal.1996.270.4.F642 |
Citation | Pajor AM (1996) Molecular cloning and functional expression of a sodium-dicarboxylate cotransporter from human kidney. Am J Physiol 270(4 Pt 2):F642-8 |
abstractText | The renal Na(+)-dicarboxylate cotransporter reabsorbs Krebs cycle intermediates, such as succinate and citrate, from the glomerular filtrate. The present study describes the cloning and characterization of the human renal Na(+)-dicarboxylate cotransporter, hNaDC-1. The amino acid sequence of hNaDC-1 is 78% identical to the rabbit renal Na(+)-dicarboxylate cotransporter, NaDC-1, and 42% identical to the rat renal Na(+)-sulfate transporter, NaSi-1. The carboxy terminus of hNaDC-1 protein contains two N-glycosylation sites that appear to be utilized. Xenopus oocytes injected with hNaDC-1 cRNA expressed a low-affinity Na(+)-dependent dicarboxylate transporter with Michaelis constant (Km) for succinate around 0.4 mM. The transport of succinate by hNaDC-1 was insensitive to the pH of the medium, whereas the transporter of citrate was stimulated by acidic pH. Northern blot analysis indicates that hNaDC-1 mRNA is found in both kidney and intestine. The gene for hNaDC-1 was localized to chromosome 17. This study provides the first demonstration that the human kidney contains a low-affinity Na(+)-dicarboxylate cotransporter with properties that resemble those of the Na(+)-dicarboxylate cotransporter on the apical membrane of the rabbit renal proximal tubule. |