Abstract
We have cloned and functionally characterized the human Na+-dependent high-affinity dicarboxylate transporter (hNaDC3) from placenta. The hNaDC3 cDNA codes for a protein of 602 amino acids with 12 transmembrane domains. When expressed in mammalian cells, the cloned transporter mediates the transport of succinate in the presence of Na+ [concentration of substrate necessary for half-maximal transport (K(t)) for succinate = 20 ± 1 μM]. Dimethylsuccinate also interacts with hNaDC3. The Na+-to-succinate stoichiometry is 3:1 and concentration of Na+ necessary for half-maximal transport (K0.5(Na+)) is 49 ± 1 mM as determined by uptake studies with radiolabeled succinate. When expressed in Xenopus laevis oocytes, hNaDC3 induces Na+-dependent inward currents in the presence of succinate and dimethylsuccinate. At a membrane potential of -50 mV, K0.5(Suc) is 102 ± 20 μM and K0.5(Na+) is 22 ± 4 mM as determined by the electrophysiological approach. Simultaneous measurements of succinate-evoked charge transfer and radiolabeled succinate uptake in hNaDC3-expressing oocytes indicate a charge-to-succinate ratio of 1:1 for the transport process, suggesting a Na+-to-succinate stoichiometry of 3:1. pH titration of citrate-induced currents shows that hNaDC3 accepts preferentially the divalent anionic form of citrate as a substrate. Li+ inhibits succinate- induced currents in the presence of Na+. Functional analysis of rat-human and human-rat NaDC3 chimeric transporters indicates that the catalytic domain of the transporter lies in the carboxy-terminal half of the protein. The human NaDC3 gene is located on chromosome 20q12-13.1, as evidenced by fluorescent in situ hybridization. The gene is >80 kbp long and consists of 13 exons and 12 introns.
| Original language | English (US) |
|---|---|
| Pages (from-to) | C1019-C1030 |
| Journal | American Journal of Physiology - Cell Physiology |
| Volume | 278 |
| Issue number | 5 47-5 |
| State | Published - Jun 22 2000 |
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Keywords
- Chromosomal localization
- Electrophysiology
- Exon-intron organization
- Human placenta
ASJC Scopus subject areas
- Physiology
- Cell Biology
Cite this
Structure, function, and genomic organization of human Na+-dependent high-affinity dicarboxylate transporter. / Wang, Haiping; Fei, You Jun; Kekuda, Ramesh; Yang-Feng, Teresa L.; Devoe, Lawrence D.; Leibach, Frederick H.; Prasad, Puttur D.; Ganapathy, Vadivel.
In: American Journal of Physiology - Cell Physiology, Vol. 278, No. 5 47-5, 22.06.2000, p. C1019-C1030.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structure, function, and genomic organization of human Na+-dependent high-affinity dicarboxylate transporter
AU - Wang, Haiping
AU - Fei, You Jun
AU - Kekuda, Ramesh
AU - Yang-Feng, Teresa L.
AU - Devoe, Lawrence D.
AU - Leibach, Frederick H.
AU - Prasad, Puttur D.
AU - Ganapathy, Vadivel
PY - 2000/6/22
Y1 - 2000/6/22
N2 - We have cloned and functionally characterized the human Na+-dependent high-affinity dicarboxylate transporter (hNaDC3) from placenta. The hNaDC3 cDNA codes for a protein of 602 amino acids with 12 transmembrane domains. When expressed in mammalian cells, the cloned transporter mediates the transport of succinate in the presence of Na+ [concentration of substrate necessary for half-maximal transport (K(t)) for succinate = 20 ± 1 μM]. Dimethylsuccinate also interacts with hNaDC3. The Na+-to-succinate stoichiometry is 3:1 and concentration of Na+ necessary for half-maximal transport (K0.5(Na+)) is 49 ± 1 mM as determined by uptake studies with radiolabeled succinate. When expressed in Xenopus laevis oocytes, hNaDC3 induces Na+-dependent inward currents in the presence of succinate and dimethylsuccinate. At a membrane potential of -50 mV, K0.5(Suc) is 102 ± 20 μM and K0.5(Na+) is 22 ± 4 mM as determined by the electrophysiological approach. Simultaneous measurements of succinate-evoked charge transfer and radiolabeled succinate uptake in hNaDC3-expressing oocytes indicate a charge-to-succinate ratio of 1:1 for the transport process, suggesting a Na+-to-succinate stoichiometry of 3:1. pH titration of citrate-induced currents shows that hNaDC3 accepts preferentially the divalent anionic form of citrate as a substrate. Li+ inhibits succinate- induced currents in the presence of Na+. Functional analysis of rat-human and human-rat NaDC3 chimeric transporters indicates that the catalytic domain of the transporter lies in the carboxy-terminal half of the protein. The human NaDC3 gene is located on chromosome 20q12-13.1, as evidenced by fluorescent in situ hybridization. The gene is >80 kbp long and consists of 13 exons and 12 introns.
AB - We have cloned and functionally characterized the human Na+-dependent high-affinity dicarboxylate transporter (hNaDC3) from placenta. The hNaDC3 cDNA codes for a protein of 602 amino acids with 12 transmembrane domains. When expressed in mammalian cells, the cloned transporter mediates the transport of succinate in the presence of Na+ [concentration of substrate necessary for half-maximal transport (K(t)) for succinate = 20 ± 1 μM]. Dimethylsuccinate also interacts with hNaDC3. The Na+-to-succinate stoichiometry is 3:1 and concentration of Na+ necessary for half-maximal transport (K0.5(Na+)) is 49 ± 1 mM as determined by uptake studies with radiolabeled succinate. When expressed in Xenopus laevis oocytes, hNaDC3 induces Na+-dependent inward currents in the presence of succinate and dimethylsuccinate. At a membrane potential of -50 mV, K0.5(Suc) is 102 ± 20 μM and K0.5(Na+) is 22 ± 4 mM as determined by the electrophysiological approach. Simultaneous measurements of succinate-evoked charge transfer and radiolabeled succinate uptake in hNaDC3-expressing oocytes indicate a charge-to-succinate ratio of 1:1 for the transport process, suggesting a Na+-to-succinate stoichiometry of 3:1. pH titration of citrate-induced currents shows that hNaDC3 accepts preferentially the divalent anionic form of citrate as a substrate. Li+ inhibits succinate- induced currents in the presence of Na+. Functional analysis of rat-human and human-rat NaDC3 chimeric transporters indicates that the catalytic domain of the transporter lies in the carboxy-terminal half of the protein. The human NaDC3 gene is located on chromosome 20q12-13.1, as evidenced by fluorescent in situ hybridization. The gene is >80 kbp long and consists of 13 exons and 12 introns.
KW - Chromosomal localization
KW - Electrophysiology
KW - Exon-intron organization
KW - Human placenta
UR - http://www.scopus.com/inward/record.url?scp=0034036769&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034036769&partnerID=8YFLogxK
M3 - Article
C2 - 10794676
AN - SCOPUS:0034036769
VL - 278
SP - C1019-C1030
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 5 47-5
ER -