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Substrate and inhibitor binding to the serotonin transporter: Insights from computational, crystallographic, and functional studies.

Talia Zeppelin, Lucy Kate Ladefoged, Steffen Sinning, Birgit Schiøtt

Neuropharmacology December 15, 2019 DOI: 10.1016/j.neuropharm.2019.02.030 (opens in new tab)

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AI-extracted from the abstract
Characteristics Review Peer reviewed
Topics Serotonin
Keywords Leut Monoamine transporters Mutagenesis X-ray crystallography Serotonin transporter sert Bacterial homologs Drug action drugs Antidepressants Substances Binding sites Computational docking Functional binding studies
Citations 20
Key findings Different experimental methods—crystallographic, computational, and functional—conclude differently on substrate and inhibitor binding modes in SERT, and each method has potential caveats.

Abstract

The serotonin transporter (SERT) belongs to the monoamine transporter family, which also includes the dopamine and norepinephrine transporters. SERT is essential for regulating serotonergic signaling by the reuptake of serotonin from the synaptic cleft back into the presynaptic neuron. Dysregulation of SERT has been implicated in several major psychiatric disorders such as major depressive disorder (MDD). MDD was among the top five leading causes of years lived with disease in 2016 and is characterized as a major global burden. Several drugs have been developed to target SERT for use in the treatment of MDD, and their respective binding modes and locations within SERT have been studied. The elucidation of the first structure of a bacterial SERT homologue in 2005 has accelerated crystallographic, computational, and functional studies to further elucidate drug binding and method of action in SERT. Herein, we aim to highlight and compare these studies with an emphasis on what the different experimental methods conclude on substrate and inhibitor binding modes, and the potential caveats of using the different types of studies are discussed. We focus this review on the binding of cognate substrate and drugs belonging to the different families of antidepressants, including tricyclic antidepressants, selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, and multimodal drugs, as well as illicit drugs such as cocaine, amphetamines, and ibogaine. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.