Mouse model studies of TMEM230-linked Parkinson's disease

通过我们之前由美国帕金森病协会和NINDS资助的工作，我们已经 在20号染色体的短臂上发现了一个新的帕金森氏病(PD)遗传基因座，并鉴定了一个 新的PD基因TMEM230。TMEM230编码一种分泌和回收囊泡的跨膜蛋白， 包括神经元中的突触小泡。TMEM230是第一个突触小泡跨膜蛋白 到目前为止已在警局确认。因此，我们的发现直接指出，大脑中的突触小泡功能障碍。 帕金森病的发病机制。TMEM230的确切生理功能及其致病机制 TMEM230介导的PD仍不清楚。基于TMEM230的分子特征及其相互关系 根据我们研究中测试的突触小泡和内体标记，我们假设TMEM230是一种 突触小泡的运输蛋白，它可能在突触小泡的生物发生，胞吐， 神经元的内吞作用和循环，以及突触传递。但这仍有待于确定在 以及TMEM230所起的作用。在上一个资金周期中，我们确定了 TMEM230作为内吞的货物蛋白与适配蛋白2的中间亚单位(AP2M1)结合 复合体(AP2)促进依赖AP2的笼状蛋白介导的内吞作用；然而，PD连锁突变影响 这个过程损害了突触小泡的循环，更具体地说，是通过影响突触前的萌芽 膜形成新的AP2/笼状蛋白包裹的回收囊泡。在本申请中，我们提出了三个具体的 目的确定TMEM230的生理功能，特别是TMEM230的功能基序 与AP2M1结合，以及TMEM230连锁PD的致病机制。我们建议开发一种 共6只TMEM230小鼠模型1，进行表型、病理和生化检查 并对黑质纹状体通路进行神经生理学鉴定。 这些小鼠模型在特定的目标3。 SV循环缺陷已成为帕金森病发病机制中的一条趋同致病途径。那里 有证据表明LRRK2、Axin和Synaptojanin 1影响网状蛋白的脱壳，而VPS35可能会破坏逆转录- 贩卖TGN。TMEM230似乎影响了SV循环的一个不同步骤，即从突触前萌发 膜形成新的AP2/笼状蛋白包被的可回收SVS。一些重要的问题仍有待解决 地址。根据我们的资源和专业知识，我们建议使用相关的 此应用程序中的鼠标模型。成功完成拟议的研究将提供必要的 了解TMEM230的生理功能及其致病机制的信息 TMEM230连接的PD。此外，由于TMEM230连锁的PD具有临床和病理特征 与经典帕金森病的结果相一致，这项研究的结果也可能对 了解其他形式帕金森病的致病机制，包括散发性帕金森病。

Through our previous work funded by the American Parkinson Disease Association and NINDS, we have discovered a new Parkinson’s disease (PD) genetic locus on the short arm of chromosome 20, and identified a new PD gene, TMEM230. TMEM230 encodes a transmembrane protein of secretory and recycling vesicles, including synaptic vesicles in neurons. TMEM230 is the first transmembrane protein of synaptic vesicles identified in PD to date. Our findings, therefore, directly point to the dysfunction of synaptic vesicles in the pathogenesis of PD. The precise physiological functions of TMEM230, and pathogenic mechanism of the TMEM230-mediated PD remain unclear. Based on the molecular features of TMEM230, and its relationship with synaptic vesicle and endosomal markers tested in our study, we hypothesize that TMEM230 is a trafficking protein of synaptic vesicles, and it may function in synaptic vesicle biogenesis, exocytosis, endocytosis and recycling, and synaptic transmission in neurons. But it remains to be determine where in the subcellular compartments and what functions that TMEM230 plays. In the previous funding cycle, we identified TMEM230 as an endocytic cargo protein that binds to the medium subunit (AP2M1) of adaptor protein 2 complex (AP2) to promote AP2-dependent clathrin-mediated endocytosis; whereas, PD-linked mutations affect this process and impair synaptic vesicle recycling, more specifically, by affecting budding from presynaptic membrane to form new AP2/clathrin-coated recycling vesicles. In this application, we propose three specific aims to determine the physiological function of TMEM230, especially the functional motifs for TMEM230 to bind to AP2M1, and the pathogenic mechanism underlying TMEM230-linked PD. We propose to develop a total of six TMEM230 mouse models in specific aim 1, to perform phenotypical, pathological and biochemical characterization in specific aim 2, and to perform neurophysiological characterization of nigrostriatal pathway in these mouse models in specific aim 3. SV recycling deficits have emerged as a convergent pathogenic pathway underlying PD pathogenesis. There is evidence that LRRK2, auxilin and synaptojanin 1 affect clathrin uncoating; and VPS35 may impair retromer- TGN trafficking. TMEM230 appears to affect a distinct step in SV recycling i.e., budding from the presynaptic membrane to form new AP2/clathrin-coated recycling SVs. A number of important issues remains to be addressed. Based on our resources and expertise, we propose to address some of these issues using relevant mouse models in this application. Successful completion of the proposed studies will provide essential information to understand the physiological function of TMEM230 and the pathogenic mechanism underlying TMEM230-linked PD. Moreover, since TMEM230-linked PD shows clinical and pathological features compatible with those in classical PD, the outcomes from this study may also have important implications in understanding the pathogenic mechanisms in other forms of PD, including sporadic PD.