AMINO ACID TRANSPORTER

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 神经递质：钠转运体(NSS)通过重摄取机制调节突触间隙的神经传递。在这个蛋白质家族中，单胺转运体包括多巴胺转运体(DAT)、5-羟色胺转运体(SERT)和去甲肾上腺素转运体(NET)，是抗抑郁药物和精神刺激剂的主要靶点。虽然这些药物的药理作用已经得到了广泛的研究，但获得的结构信息很少，从而阻碍了对其抑制机制的深入了解，并阻碍了基于结构的药物设计。我目前的研究重点是利用细菌同源物研究神经递质转运体中抗抑郁药结合部位的原子结构。通过应用一种名为闪烁邻近分析(SPA)的药物筛选策略，我们确定了一组与细菌转运蛋白具有结合亲和力的药物。第一个靶向地昔帕明是一种三环抗抑郁药，已经与细菌氨基酸转运体Leut共结晶。通过将人类蛋白质的序列连接到亮氨酸-地塞帕明结构上，建立了人类蛋白质的同源模型。我进一步设计了人类SERT的功能丧失突变和人类DAT的功能获得突变，以提供强有力的证据支持药物结合口袋在人类神经递质转运体中可能是保守的。其他候选药物正在接受测试。这项工作将揭示不同的抗抑郁剂如何阻断神经递质转运体，防止构象变化，从而抑制底物转运。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Neurotransmitter:sodium symporters (NSS) regulate neurotransmission at the synaptic cleft through a reuptake mechanism. In this protein family, monoamine transporters including dopamine transporter (DAT), serotonin transporter (SERT) and norepinephrine transporter (NET), are primary targets for antidepressants and psychostimulants. Although the pharmacological effects of these drugs have been studied extensively, little structural information is available, thereby hampering the thorough understanding of the inhibition mechanism and hindering structure based drug design.My current research is focused on studying atomic structures of antidepressants binding sites in neurotransmitter transporters using bacterial homologues. By applying a drug screening strategy called scintillation proximity assay (SPA), We identified a group of drugs that have binding affinity to bacterial transporters. The first drug target desipramine, a tricyclic antidepressant, has been cocrystallized with LeuT, a bacterial amino acid transporter. Homology models of human proteins were built by threading their sequences onto the LeuT-desipramine structure. I further designed both loss-of-function mutations in human SERT and gain-of-function mutations in human DAT to provide strong evidence supporting that the drug binding pockets are probably conserved in human neurotransmitter transporters. The other drug candidates are being test. This work will reveal how different antidepressants block neurotransmitter transporters, prevent conformational changes, and therefore inhibit substrate transport.