Trafficking and Regulation of Monoamine Transporters

描述（由申请方提供）：单胺再摄取是一种主要机制 调节神经元单胺水平和终止突触 传输再摄取由质膜转运蛋白介导， 可卡因、甲基苯丙胺和摇头丸等精神兴奋剂的主要目标 （“Ecoxetine”），以及治疗药物如氟西汀（百忧解）， 西布曲明（西布曲明）、安非他酮（安非他酮）和哌醋甲酯（利他林）。 这些药物阻断再摄取，导致神经元单胺水平升高， 水平和增强的突触后反应。最近的证据表明， 转运蛋白受到细胞信号传导途径的急性调节。 转运蛋白的调节与转运蛋白的动态变化相关联 细胞表面呈递，表明膜运输是基本的 转运蛋白的稳态和调节。然而，细胞和分子 关于运输管制和贩运的机制尚未建立， 定义了考虑到药物转运体阻断的显著效果 在突触传递上发挥作用，很可能是转运蛋白 隔离还对神经元信号传导具有显著的下游效应。 此外，运输机可用性的调整肯定会产生重大影响。 对精神药物疗效的影响。本项目的主要目标 旨在阐明介导急性心肌梗死的细胞和分子机制， 运输管制和贩运。这条调查路线将继续下去 通过检验以下假设： (1)转运蛋白经历组成性内化和再循环，以及（2） 转运蛋白调控是通过改变转运蛋白的运输来实现的 动力学这些假设是基于强有力的初步数据， 多巴胺转运蛋白（DAT）经历组成性内体运输， 蛋白激酶C（PKC）的激活直接改变了DAT的运输。的 提出的假设将通过直接分析基础和调节 细胞系中的转运蛋白运输动力学。内在结构域介导 基础和PKC调节的DAT运输将使用分子生物学方法进行鉴定。 截短和诱变方法。预计这些方法 将提供一个清晰和全面的机制， 急性转运蛋白调节预计这些结果将产生重大影响。 对今后针对单胺相关药物滥用的治疗策略的影响 和精神疾病。此外，这些成果将大大改善我们的 了解影响单胺可用性的因素， 大脑中的信号。

DESCRIPTION (provided by applicant): Monoamine reuptake is a major mechanism for regulating extraneuronal monoamine levels and terminating synaptic transmission. Reuptake is mediated by plasma membrane transporters that are the primary targets for psychostimulants such as cocaine, methamphetamine and MDMA ("Ecstasy"), as well as for therapeutic drugs such as fluoxetine (Prozac), sibutramine (Meridia), bupropion (Wellbutrin) and methylphenidate (Ritalin). These agents block reuptake, resulting in elevated extraneuronal monoamine levels and enhanced postsynaptic responses. Recent evidence demonstrates that transporters are subject to acute regulation by cellular signaling pathways. Transporter regulation is coupled to dynamic changes in transporter cell-surface presentation, suggesting that membrane trafficking is fundamental to transporter homeostasis and regulation. However, the cellular and molecular mechanisms governing transporter regulation and trafficking are not yet defined. Given the pronounced effect pharmacological transporter blockade exerts on synaptic transmission, it is highly likely that transporter sequestration also has significant downstream effects on neuronal signaling. Moreover, modulation of transporter availability is certain to have significant impact on the efficacy of psychoactive drugs. The major goals of this project are to elucidate the cellular and molecular mechanisms mediating acute transporter regulation and trafficking. This investigative line will be pursued by testing the following hypotheses: (1) Transporters undergo constitutive internalization and recycling, and (2) transporter regulation is achieved by altering transporter trafficking kinetics. These hypotheses are based on strong preliminary data that the dopamine transporter (DAT) undergoes constitutive endosomal trafficking and that protein kinase C (PKC) activation directly alters DAT trafficking. The proposed hypotheses will be tested by directly analyzing basal and regulated transporter trafficking kinetics in cell lines. Intrinsic domains mediating basal and PKC-regulated DAT trafficking will be identified using molecular truncation and mutagenesis approaches. It is expected that these approaches will provide a clear and comprehensive picture of the mechanisms underlying acute transporter modulation. Such results are expected to have a significant impact on future therapeutic strategies aimed at monoamine-related drug abuse and mental illnesses. Moreover, the outcomes will greatly improve our understanding of the factors contributing to monoamine availability and signaling in the brain.