Trafficking and Regulation of Monoamine Transporters

描述(申请人提供)：单胺再摄取是一种主要机制 调节神经元外单胺水平和终止突触 变速箱。重摄取是由质膜转运蛋白介导的， 可卡因、甲基苯丙胺和MDMA等精神刺激剂的主要目标 (“摇头丸”)，以及治疗药物，如氟西汀(百忧解)， 西布曲明(子午线)、安非他酮(威布曲林)和哌醋甲酯(利他林)。 这些药物阻断再摄取，导致神经元外单胺升高。 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通路的强烈调控。 运输商的监管与运输商的动态变化相结合 细胞表面呈现，表明膜运输是基本的 来运输动态平衡和调节。然而，细胞和分子 管理运输商监管和贩运的机制还没有 已定义。鉴于明显的效果，药理转运体阻断 作用于突触传递，很可能是转运蛋白 隔离对神经元信号转导也有显著的下游影响。 此外，运输机可用性的调制肯定会有显著的影响 对精神活性药物疗效的影响。这个项目的主要目标是 是为了阐明细胞和分子机制介导急性胰腺炎 运输商监管和贩运。这条调查路线将继续下去 通过检验以下假设： (1)转运体经历结构性内部化和再循环；(2) 运输商监管是通过改变运输车贩运来实现的 运动学。这些假设是基于强有力的初步数据，即 多巴胺转运体(DAT)经历结构性内体转运和 蛋白激酶C(PKC)的激活直接改变DAT的运输。这个 提出的假设将通过直接分析基本假设和监管假设进行验证 细胞系中转运蛋白的运输动力学。本征域中介 基本的和PKC调节的DAT运输将使用分子识别 截断和突变方法。预计这些方法 将提供一个清晰和全面的基础机制的图景 急性转运蛋白调节。这样的结果预计将产生重大的 对未来针对单胺类药物滥用的治疗策略的影响 和精神疾病。此外，结果将极大地改善我们的 了解影响单胺可获得性的因素和 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.