A direct interaction of cholesterol with the dopamine transporter prevents its out-to-inward transition

Zeppelin, Talia; Ladefoged, Lucy Kate; Sinning, Steffen; Periole, Xavier; Schiøtt, Birgit

doi:10.1371/journal.pcbi.1005907

Cited by 91 publications

(120 citation statements)

References 111 publications

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“…First, we tracked the interactions between residues forming the gates in the extracellular pathway Although both conformations stay stable and 5HT remains bound, we were intrigued by the observation that the outward-open state does not drift towards the occluded state despite being occupied by all required substrates, and in contrast to previous reports for 5I6X [53]. We therefore investigated the protein-ligand interactions in the orthosteric binding site for potential explanations for the different interaction patterns in our systems.…”

Section: Comparison Of Outward-occluded and Outward-open States Of Hsertmentioning

confidence: 98%

A structural model of the human serotonin transporter in an outward-occluded state

Hellsberg

Ecker

Stary-Weinzinger

et al. 2019

Preprint

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The human serotonin transporter hSERT facilitates the reuptake of its endogenous substrate serotonin from the synaptic cleft into presynaptic neurons after signaling. Reuptake regulates the availability of this neurotransmitter and therefore hSERT plays an important role in balancing human mood conditions. In 2016, the first 3D structures of this membrane transporter were reported in an inhibitor-bound, outward-open conformation. These structures revealed valuable information about interactions of hSERT with antidepressant drugs. Nevertheless, the question remains how serotonin facilitates the specific conformational changes that open and close pathways from the synapse and to the cytoplasm as required for transport. Here, we present a serotonin-bound homology model of hSERT in an outward-occluded state, a key intermediate in the physiological cycle, in which the interactions with the substrate are likely to be optimal. Our approach uses two template structures and includes careful refinement and comprehensive computational validation. According to microsecond-long molecular dynamics simulations, this model exhibits interactions between the gating residues in the extracellular pathway, and these interactions differ from those in an outward-open conformation of hSERT bound to serotonin.Moreover, we predict several features of this state by monitoring the intracellular gating residues, the extent of hydration, and, most importantly, protein-ligand interactions in the central binding site. The results illustrate common and distinct characteristics of these two transporter states and provide a starting point for future investigations of the transport mechanism in hSERT.

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Section: Comparison Of Outward-occluded and Outward-open States Of Hsertmentioning

confidence: 98%

A structural model of the human serotonin transporter in an outward-occluded state

Hellsberg

Ecker

Stary-Weinzinger

et al. 2019

Preprint

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show abstract

“…Structural data indicate that DAT interacts with a molecule of cholesterol to permit proper folding (Penmatsa et al, 2013), and that its association to cholesterol is essential for DAT function, especially neurotransmitter reuptake (Hong and Amara, 2010;Jones et al, 2012;Zeppelin et al, 2018)}. Given that it is unclear whether the essential association of cholesterol to DAT is associated to its Flot1-dependent partitioning, we examined whether the loss of Flot1 disrupts basal parameters of the DAergic system.…”

Section: Loss Of Flot1 In Da Neurons Does Not Affect Basal Neuron Funmentioning

confidence: 99%

Membrane composition influences the conformation and function of the dopamine transporter in vivo

Fong

Erreger

Choi

et al. 2019

Preprint

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words)The biophysical and biochemical properties of membrane lipids can alter the conformation and function of membrane-spanning proteins, yet the specific, physiological consequence in vivo of changing the membrane milieu for a specific protein has been rarely investigated. Using various genetic approaches to eliminate expression of the membrane-associated protein Flotillin-1, we have found that the lipid environment of the dopamine transporter (DAT) is necessary for mice to respond to amphetamine but not cocaine, because the localization of DAT to cholesterol-rich membranes is required for a DAT conformation that is essential for reverse transport of dopamine. Furthermore, a conditional rather than constitutive loss-of-function approach was necessary to reveal this phenotype, indicating a broader role for membrane-protein interactions that are modulated by Flotillin-1. Taken together, these findings demonstrate how interaction of a transmembrane protein with its membrane environment can regulate distinct events in the vertebrate brain that give rise to specific behavioral outcomes.

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“…2018). The simulations revealed several cholesterol–protein binding and unbinding events, and it was suggested from the simulations that the sites present in the dDAT crystal structures are conserved across the entire human MAT family (Fig.…”

Section: Membrane Proteins and Their Regulationmentioning

confidence: 99%

Understanding Conformational Dynamics of Complex Lipid Mixtures Relevant to Biology

et al. 2018

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A direct interaction of cholesterol with the dopamine transporter prevents its out-to-inward transition

Cited by 91 publications

References 111 publications

A structural model of the human serotonin transporter in an outward-occluded state

A structural model of the human serotonin transporter in an outward-occluded state

Membrane composition influences the conformation and function of the dopamine transporter in vivo

Understanding Conformational Dynamics of Complex Lipid Mixtures Relevant to Biology

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