PUBLICATION

Species-specific Influence of Lithium on the Activity of SLC13A5 (NaCT): Lithium-induced Activation is Specific for the Transporter in Primates

Authors
Gopal, E., Babu, E., Ramachandran, S., Bhutia, Y.D., Prasad, P.D., Ganapathy, V.
ID
ZDB-PUB-150127-14
Date
2015
Source
The Journal of pharmacology and experimental therapeutics   353(1): 17-26 (Journal)
Registered Authors
Keywords
citric acid, drug transport, hepatic transport, membrane transport, transporters
MeSH Terms
  • Animals
  • Biological Transport
  • Caenorhabditis elegans
  • Cell Line
  • Citrates/metabolism
  • Dogs
  • Female
  • Humans
  • Lithium Compounds/pharmacology*
  • Macaca mulatta
  • Mice
  • Mutation
  • Oocytes/metabolism
  • Pan troglodytes
  • Rats
  • Species Specificity
  • Symporters/genetics
  • Symporters/metabolism*
  • Xenopus laevis
  • Zebrafish
PubMed
25617245 Full text @ J. Pharmacol. Exp. Ther.
Abstract
NaCT (SLC13A5) is a Na+-coupled transporter for Krebs cycle intermediates; it is expressed predominantly in the liver. Human NaCT is relatively specific for citrate compared to other Krebs cycle intermediates. The transport activity of human NaCT is stimulated by Li+ whereas that of rat NaCT is inhibited by Li+. Here we studied the influence of Li+ on NaCTs cloned from eight different species. Li+ stimulated the activity of only NaCTs from primates (human, chimpanzee and monkey); in contrast, NaCTs from non-primate species (mouse, rat, dog, and zebrafish) were inhibited by Li+. C. elegans NaCT was not affected by Li+. With human NaCT, the Li+-induced increase in transport activity was associated with the conversion of the transporter from a low-affinity/high-capacity type to a high-affinity/low-capacity type. H+ was able to substitute for Li+ in eliciting the stimulatory effect. The amino acid phenylalanine at position 500 in human NaCT was critical for Li+/H+-induced stimuation. Mutation of this amino acid to tryptophan (F500W) markedly increased the basal transport activity of human NaCT in the absence of Li+, but the ability of Li+ to stimulate the transporter was almost completely lost with this mutant. Substitution of Phe-500 with tryptophan in human NaCT converted the transporter from a low-affinity/high-capacity type to a high-affinity/low-capacity type, an effect similar to that of Li+ on the wild type NaCT. These studies show that Li+-induced activation of NaCT is specific for the transporter in primates and that the region surrounding Phe-500 in primate NaCTs is important for the Li+ effect.
Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping