Elucidating the trafficking mechanisms of effector proteins to the Plasmodium infected red blood cell

项目摘要 恶性疟原虫是一种致命的人类寄生虫，可导致疟疾，造成近45万人死亡 每年都有人死亡。疟疾在世界上大片地区流行，人口约40亿，而它 每年影响约2.5亿人。目前还没有有效的疟疾疫苗和抗疟疾药物 是治疗的主要手段。目前，这种寄生虫已经对所有临床可用的药物产生了抗药性。 抗疟疾药物和这些抗药性菌株正在世界各地传播，威胁着所有 在过去十年中，在抗击这种疾病方面取得了进展。因此，当务之急是我们 不断产生新的药物并确定潜在的药物靶点，以保持对这种邪恶疾病的领先地位。这个 这种毁灭性的寄生虫病的临床表现，包括死亡，是由P. 宿主红细胞(RBC)内的恶性疟原虫。为了在红细胞内建立适合生长的栖息地，疟疾 寄生虫完全改变了宿主细胞。它改变了红细胞的新陈代谢，使红细胞变得更加僵硬 以使受感染的红细胞更难通过毛细血管，修改红细胞膜以允许 有利于营养物质的移动，并改变红细胞的结合特性，使感染细胞能够结合 血管内壁的内皮细胞。这些变化的总和会导致疾病和死亡，因为 例如，感染恶性疟原虫的红细胞与内皮细胞结合会堵塞脑血管。 导致血栓，最终导致死亡。抑制受感染的红细胞是通过 寄生虫通过鲜为人知的方式运输到宿主细胞的数百种蛋白质的作用 机械装置。寄生虫效应蛋白的输出对于转化红细胞是必不可少的，因此，对于 引发疾病。在寄生虫细胞质中合成的寄生虫效应蛋白需要 通过三到四个细胞膜运输，以便到达它们在宿主红细胞中的作用部位。这个 识别、分类和将这些寄生虫效应器运送到受感染的红细胞的分子机制仍然存在 以确定身份。拟议中的研究旨在揭开控制关键早期事件的分子过程 在指向主机RBC的路径上设置寄生虫效应器。为实现这一目标，我们将追求两个目标。首先，我们 将在寄生虫的内质网中产生蛋白质的条件突变，这些突变可能是 出口寄生虫效应器所需的。这些突变体将通过遗传、细胞和生化手段进行分析。 确定它们在寄生虫蛋白出口中的作用的方法。第二，我们将不偏不倚地 交互作用组筛选方法，使用基于邻近性的标记方法并发现 Usher将蛋白质输出到它们在宿主红细胞中的作用部位。达到研究计划的目标 将揭示恶性疟原虫关键和独特的蛋白质转运机制，可能成为抗疟疾的靶点 药物开发。

Project Summary Plasmodium falciparum is a deadly human parasite that causes malaria and is responsible for nearly 450,000 deaths every year. Malaria is endemic in large regions of the world, home to about 4 billion people and it affects ~250 million people annually. There are no effective vaccines against malaria and antimalarial drugs are the mainstay of treatment. At this time, the parasite has gained resistance to all clinically available antimalarial drugs and these drug-resistant strains are spreading throughout the world, threatening all the progress that has been made against this disease in the last decade. Therefore, it is imperative that we constantly generate new drugs and identify potential drug targets to stay ahead of this nefarious disease. The clinical manifestations of this devastating parasitic disease, including death, are caused by the growth of P. falciparum within the host red blood cell (RBC). To build a suitable habitat for growth inside RBCs, the malaria parasite completely transforms the host cell. It changes the metabolism of the RBC, makes the RBC more rigid such that it is harder for the infected RBC to pass through capillaries, modifies the RBC membrane to allow for favorable movement of nutrients, and alters the binding properties of the RBC so that the infected cell can bind to the endothelial cells lining blood vessels. The sum of these changes leads to disease and death, for instance, binding of the P. falciparum infected RBC to endothelial cells can clog blood vessels in the brain leading to clots that eventually result in death. The subjugation of the infected RBC is accomplished through the action of several hundred proteins that the parasite transports to the host cell via poorly understood mechanisms. The export of parasite effector proteins is essential for transforming the RBC and therefore, for causing disease. Parasite effector proteins that are synthesized in the parasite cytoplasm need to be transported across three or four cellular membranes in order to reach their site of action in the host RBC. The molecular mechanisms that recognize, sort, and transport these parasite effectors to the infected RBC remain to be identified. The proposed studies aim to unravel the molecular processes that govern key early events that set parasite effectors on the path to the host RBC. We will pursue two aims to accomplish this goal. First, we will generate conditional mutants of proteins in the endoplasmic reticulum of the parasite that are potentially required for export of parasite effectors. The mutants will be analyzed using genetic, cellular, and biochemical approaches to determine their roles in the export of parasite proteins. Second, we will take an unbiased interactome screening approach that uses a proximity-based labeling approach and discover proteins that usher exported proteins to their site of action in the host RBC. Attaining the objectives of the research program will reveal key and unique protein trafficking mechanisms of P. falciparum that may be targeted for antimalarial drug development.