Roles of endosomal phosphoinositides in intracellular trafficking

内溶酶体运输是一个严格调控的过程，涉及膜融合和分裂事件，其确保内体、溶酶体和其他细胞内细胞器或囊泡内货物的适当递送和交换。它是几种细胞功能所必需的，如蛋白质和脂质转运、自噬和溶酶体中大分子的降解。它是如何调节的是细胞生物学中的一个基本问题。我们的研究计划打算使用病毒作为手段来监测和了解细胞中的囊泡运输。事实上，病毒已经进化出利用甚至调节内体成熟或内溶酶体运输的机制，因为它可以决定感染是否成功。因此，它们可以代表用于研究细胞贩运途径的强大和宝贵的工具。我们发现Vac 14/Fig 4/PIKfyve复合物的蛋白质，其调节磷脂酰肌醇（3，5）二磷酸在溶酶体内膜的合成，是埃博拉病毒（EboV）和严重急性呼吸综合征冠状病毒（SARS-CoV）感染所必需的。合成PI（3，5）P2的酶复合物如何被激活以及PI（3，5）P2在内溶酶体运输中的作用仍不清楚。在这里，我们建议使用EboV和SARS-CoV来回答这些问题。** 这项研究计划的目标是了解这种复合物及其产生的磷酸肌醇是如何调节的，以及它们如何控制细胞内溶酶体的运输，这是一个基本的细胞过程。假设：* 内体磷酸肌醇PI（3，5）P2对于病毒颗粒运输至发生病毒融合的细胞内区室至关重要。*短期目标：*1）检查PI（3，5）P2水平的遗传和化学操作的影响 *2）进行Vac 14/Fig 4/PIKfyve复合物的分子解剖 *3）鉴定PI（3，5）P2效应物 * 我们的长期目标是获得对Vac 14/Fig 4/PIKfyve相互作用组和功能的分子理解。为了实现我们的目标，我们将使用遗传学，化学生物学和病毒学工具的组合。将这些特定工具与我们在分子/细胞生物学和病毒进入方面的专业知识相结合，我们希望填补对内溶酶体运输的理解以及这一基本过程如何被病毒病原体劫持的空白。

Endolysosomal trafficking is a tightly regulated process that involves membrane fusion and fission events, which ensure proper delivery and exchange of cargoes within endosomes, lysosomes, and other intracellular organelles or vesicles. It is essential for several cellular functions such as protein and lipid transport, autophagy, and degradation of macromolecules in lysosomes. How it is regulated is a fundamental issue in cellular biology. Our research program intends to use viruses as means to monitor and understand vesicular trafficking in cells. Indeed, viruses have evolved mechanisms to use and even regulate endosomal maturation or endolysosomal trafficking, since it can determine whether the infection is successful or not. Therefore, they can represent powerful and invaluable tools for the study of cellular trafficking pathways. We found that proteins of the Vac14/Fig4/PIKfyve complex, which regulates the synthesis of the phosphoinositide(3,5)bisphosphate at the endolysosomal membrane, are essential for infection by Ebola virus (EboV) and severe acute respiratory syndrome coronavirus (SARS-CoV). How the enzymatic complex synthesizing PI(3,5)P2 is activated and the role of PI(3,5)P2 in endolysosomal trafficking remain unclear. Here, we propose to use EboV and SARS-CoV to answer these questions. ******The goal of this research program is to understand how this complex and its resulting phosphoinositide are regulated and how they control endolysosomal trafficking in cells, a fundamental cellular process.****Hypothesis:***The endosomal phosphoinositide PI(3,5)P2 is critical for the trafficking of viral particles to intracellular compartments where viral fusion occurs.****Short-term objectives:****1) Examine the effect of genetic and chemical manipulation of PI(3,5)P2 levels***2) Perform a molecular dissection of the Vac14/Fig4/PIKfyve complex***3) Identify PI(3,5)P2 effectors****Our long term goal is to gain a molecular understanding of the Vac14/Fig4/PIKfyve interactome and function.****To meet our objectives, we will use a combination of genetic, chemical biology, and virological tools. Combining these specific tools with our expertise in molecular/cell biology and viral entry, we hope to fill a gap in the understanding of endolysosomal trafficking and how this fundamental process can be hijacked by viral pathogens.**