Some of the body's most important signalling molecules - such as serotonin and dopamine - rely on transporters to successfully clear them out of the extracellular space in the brain. Transporters move these neurotransmitters across the cell membrane by capitalizing on differences in ionic gradients. Eric Gouaux and his colleagues have now captured the crystal structure of a bacterial sodium/chloride-dependent transporter, which moves leucine across membranes. The structure, detailed in a paper published online by Nature, is the first glimpse of this large class of neurotransmitter sodium symporters.
The newly described structure has revealed the binding sites for ions and leucine, together with the 'gates' that must be opened to allow access to these sites. Gouaux and his team note that dysfunction of sodium/chloride-dependent transporters in humans contributes to multiple disorders, including Parkinson's disease and epilepsy. One member of this family of transporters, which moves serotonin, is currently targeted by fluoxetine (Prozac). Knowing the binding sites of these synaptic players will probably help experts to design better drug treatments for depression and neurodegenerative disorders.
Eric J. E. Gouaux
Columbia University, New York, NY, USA.
Abstract available online.
(C) Nature press release.
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