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Dr. Lim, Carmay

Distinguished Research Fellow
  • +886-2-2789-9043 (Lab) (Room No: N117)
  • +886-2-2652-3031 (Office)
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  • Computational Biophysics
  • Computational Chemistry
  • Bioinformatics

Education and Positions:
  • 1984, Ph.D. in Chemical Physics, University of Minnesota, Minneapolis

    1979, B.S. in Chemistry, Royal Holloway College, London University


Highlight Detail

Competition between Li+ and Na+ in sodium transporters and receptors: Which Na+-Binding sites are “therapeutic” Li+ targets?

Dr. Lim, Carmay
Chemical Science, Apr 02, 2018

Sodium (Na+) acts as an indispensable allosteric regulator of the activities of biologically important neurotransmitter transporters and G-protein coupled receptors (GPCRs), which comprise well-known drug targets for psychiatric disorders and addictive behavior. How selective these allosteric Na+-binding sites are for the cognate cation over abiogenic Li+, a first-line drug to treat bipolar disorder, is unclear. Here, we reveal how properties of the host protein and its binding cavity affect the outcome of the competition between Li+ and Na+ for allosteric binding sites in sodium transporters and receptors. We show that rigid Na+-sites that are crowded with multiple protein ligands are well-protected against Li+ attack, but their flexible counterparts or buried Na+-sites containing only one or two protein ligands are vulnerable to Li+ substitution. These findings suggest a novel possible mode of Li+ therapeutic action: By displacing Na+ bound by ≤2 protein ligands in buried GPCR sites and stabilizing the receptor's inactive state, Li+ could prohibit conformational changes to an active state, leading to lower cytosolic levels of activated guanine nucleotide-binding proteins, which are hyperactive/overexpressed in bipolar disorder patients.