Laboratory for Membrane Protein Dynamics, Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Nano-Science Center, Department of Chemistry, Faculty of Science, University of Copenhagen, Copenhagen, Denmark.
Nat Commun. 2022 May 4;13(1):2446. doi: 10.1038/s41467-022-30154-5.
The dopamine transporter facilitates dopamine reuptake from the extracellular space to terminate neurotransmission. The transporter belongs to the neurotransmitter:sodium symporter family, which includes transporters for serotonin, norepinephrine, and GABA that utilize the Na gradient to drive the uptake of substrate. Decades ago, it was shown that the serotonin transporter also antiports K, but investigations of K-coupled transport in other neurotransmitter:sodium symporters have been inconclusive. Here, we show that ligand binding to the Drosophila- and human dopamine transporters are inhibited by K, and the conformational dynamics of the Drosophila dopamine transporter in K are divergent from the apo- and Na-states. Furthermore, we find that K increases dopamine uptake by the Drosophila dopamine transporter in liposomes, and visualize Na and K fluxes in single proteoliposomes using fluorescent ion indicators. Our results expand on the fundamentals of dopamine transport and prompt a reevaluation of the impact of K on other transporters in this pharmacologically important family.
多巴胺转运体促进多巴胺从细胞外间隙重摄取，从而终止神经递质传递。该转运体属于神经递质：钠离子共转运体家族，其中包括 5-羟色胺、去甲肾上腺素和 GABA 的转运体，它们利用 Na 梯度驱动底物摄取。几十年前，已经表明 5-羟色胺转运体也反向转运 K，但对其他神经递质：钠离子共转运体中的 K 偶联转运的研究尚无定论。在这里，我们表明配体与果蝇和人多巴胺转运体的结合受到 K 的抑制，并且 K 状态下的果蝇多巴胺转运体的构象动力学与 apo 和 Na 状态不同。此外，我们发现 K 增加了果蝇多巴胺转运体在脂质体中的多巴胺摄取，并使用荧光离子指示剂在单个蛋白脂质体中可视化 Na 和 K 通量。我们的研究结果扩展了多巴胺转运的基本原理，并促使重新评估 K 对该药理学上重要家族中其他转运体的影响。
