Cell-intrinsic mechanisms of presynaptic assembly

派：库尔山，佩里·T。 项目摘要/摘要 突触是大脑中基本的信息处理单位，它们的功能障碍导致 神经发育和神经精神障碍。突触的发育和组织是在 部分是由一种称为突触细胞黏附分子(SCAMS)的跨膜蛋白所致，而突触细胞黏附分子的突变 诈骗基因与自闭症、精神分裂症和智力残疾等疾病高度相关， 还有其他的。突触形成的主要模型表明，它是由跨突触启动的 然而，缺乏这种模型的活体证据。在这里，我们建议揭开非跨性- 突触细胞-突触前组装的内在分子程序，介导定位、运输和 SCAMS和其他完整的突触前蛋白的亚细胞功能。 我们的初步证据表明，突触前骗局的胞内结构域 SYG-2/neparin是突触前组织所必需的细胞自主调节蛋白。此外，我们发现， 神经肽在突触前活动区的定位是通过与活动区的细胞内相互作用来实现的 支架蛋白和动蛋白马达。最后，我们发现，依赖诈骗和其他活跃 运动蛋白运输的区带蛋白依赖于轴突生长的阶段。基于这些发现，我们 假设突触前组装在很大程度上是由细胞内在机制调节的。我们建议 追求三个具体目标来描述支配(1)细胞内招募的机制 SCAMS，(2)通过SCAM介导的细胞骨架在细胞内组织适当的突触间隔 重排，以及(3)通过激动素传递和重新分配SCAMS和其他活性区域蛋白。 轴突生长不同阶段的依赖和独立机制(目标3)。 为了研究这些假说，我们利用人的遗传可控性和刻板印象的神经系统 线虫、线虫以及创新的成像和遗传方法。线虫有很长的 揭示基础突触生物学的历史和我们以前发表的结果和初步数据 让我们做好充分的准备，充分利用这个系统的力量。总而言之，我们提议的研究将揭示 细胞内在机制如何在突触形成中控制SCAMS的功能。这些研究具有 有可能揭示导致神经发育障碍的分子机制 SCAM功能的缺陷，从而为制定具体的治疗干预措施提供了目标。

PI: Kurshan, Peri T. PROJECT SUMMARY/ABSTRACT Synapses are the fundamental information processing units in the brain and their dysfunction leads to neurodevelopmental and neuropsychiatric disorders. Synapse development and organization is mediated in part by a class of transmembrane proteins called synaptic cell-adhesion molecules (sCAMs), and mutations in sCAM genes is highly associated with diseases such as autism, schizophrenia and intellectual disability, among others. The dominant model for synapse formation suggests that it is initiated by the trans-synaptic binding of sCAMs, however in vivo evidence for that model is lacking. Here we propose to uncover non-trans- synaptic cell-intrinsic molecular programs for presynaptic assembly that mediate the localization, trafficking and subcellular functions of sCAMs and other integral presynaptic proteins. Our preliminary evidence suggests that the intracellular domains of the presynaptic sCAMs neurexin and syg-2/nephrin are cell-autonomously required for presynaptic organization. Moreover, we find that the localization of neurexin to the presynaptic active zone is mediated by intracellular interactions with active zone scaffold proteins and kinesin motors. Finally, we have found that the dependence of sCAMs and other active zone proteins on transport by kinesins depends on the stage of axonal outgrowth. Based on these findings, we hypothesize that presynaptic assembly is mediated in large part by cell-intrinsic mechanisms. We propose to pursue three Specific Aims to characterize the mechanisms that govern (1) the intracellular recruitment of sCAMs, (2) the intracellular organization of proper synapse spacing by sCAM-mediated cytoskeletal rearrangement, and (3) the delivery and reallocation of sCAMs and other active zone proteins by kinesin- dependent and independent mechanisms at different stages of axonal outgrowth (Aim 3). To investigate these hypotheses, we leverage the genetic tractability and stereotyped nervous system of the nematode C. elegans, along with innovative imaging and genetic approaches. C. elegans has a long history of revealing fundamental synaptic biology and our previous published results and preliminary data position us well to take advantage of the power of this system. Collectively our proposed research will reveal how cell-intrinsic mechanisms govern the function of sCAMs in synapse formation. These studies have the potential to uncover the molecular mechanisms underlying neurodevelopmental disorders that result from defects in sCAM function, and thus provide targets for the development of specific therapeutic interventions.