Macromolecular Transport in Asexual Malaria Parasites

无性疟原虫中的大分子运输

• 批准号: 6729457
• 负责人: Theodore F Taraschi
• 金额: $ 31.12万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6729457
• 关键词: G protein; Plasmodium falciparum; actins; cell component structure /function; cell membrane; cytoplasm; electron microscopy; erythrocytes; host organism interaction; human tissue; intracellular parasitism; intracellular transport; macromolecule; malaria; membrane activity; myosins; protein biosynthesis; protein localization; protein quantitation /detection; protein structure function; protein transport; radionuclides; secretory protein; tissue /cell culture; vesicle /vacuole

DESCRIPTION (provided by the applicant): During the development of the asexual stage of the human malaria parasite, Plasmodium falciparum, the composition, structure and function of the host cell membrane is dramatically altered, including the ability to adhere to vascular endothelium. Crucial to these changes is the transport of parasite proteins, which become associated with the erythrocyte membrane. One of the most exciting problems in malaria cell biology is the mechanism by which intraerythocytic parasites target proteins to the RBC membrane, thus controlling its environment and contributing to the pathology of malaria. Protein targeting beyond the parasite plasma membrane (PPM) requires unique pathways, given the parasites intracellular location within a vacuolar membrane and the lack of organelles, secretory proteins and biosynthetic machinery in the host cell. It is not clear how these proteins cross the PVM or how they traverse the erythrocyte cytosol to reach their final destinations. It is our hypothesis that intraerythrocytic parasites export homologues of COPII, N-ethylmaleimide-sensitive factor (NSF) and other secretory proteins into the erythrocyte cytosol to generate a G-protein regulated secretory system that transports parasite proteins to the host cell membrane. Treatment of parasitized erythrocytes with aluminum fluoride (AIF) provided evidence of a G-protein mediated intraerythrocytic secretory pathway. In Aim 1, we will characterize the formation of intraerythrocytic transport vesicles, purify them from the erythrocyte of treated IRBC and determine their protein composition by LC/LC/MS/MS. Aim 2 is designed to investigate vesicle docking and fusion between intraerythrocytic secretory vesicles and the erythrocyte plasma membrane. Vesicle transport to the (parasite-derived) Maurer's clefts in the erythrocyte cytosol and the erythrocyte membrane appears to be actin-erythrocyte myosin mediated. Aim 3 will characterize the role of actin and myosin in vesicle formation and the transport of intraerythrocytic secretory vesicles to the RBC plasma membrane. The export and establishment of a specialized secretory system to a distant location is unusual in cell biology and points to the parasite 'transforming' the host cell into a secretory cell in order to meet the needs of the erythrocytic stage of infection. The identification of the key events in vesicle formation, transport, docking or fusion could lead to the identification of unique processes or molecules that might offer new drug targets.

描述（由申请人提供）：在人类疟原虫的无性阶段的发展过程中，恶性疟原虫，宿主细胞膜的组成，结构和功能发生了巨大变化，包括粘附于血管内皮的能力。这些变化的关键是寄生虫蛋白的转运，它们与红细胞膜有关。疟疾细胞生物学中最令人兴奋的问题之一是脑内寄生虫将蛋白靶向RBC膜的机制，从而控制其环境并有助于疟疾的病理。考虑到胶水膜内寄生虫的细胞内位置以及缺乏细胞器，分泌蛋白和宿主细胞中的生物合成机械，寄生虫质膜（PPM）超出寄生虫质膜（PPM）需要独特的途径。目前尚不清楚这些蛋白质如何跨越PVM，或者它们如何穿越红细胞细胞溶胶以达到最终目的地。我们的假设是，肠内寄生虫导出CopII，N-乙基甲基酰亚胺敏感因子（NSF）和其他分泌蛋白的同源物中，将其传递给宿主细胞膜的寄生虫蛋白将gprotein调节的分泌系统传递到宿主细胞膜上。 用氟化铝（AIF）处理寄生的红细胞（AIF）提供了G蛋白介导的肠内分泌途径的证据。在AIM 1中，我们将表征肠内转运囊泡的形成，从处理的IRBC的红细胞中净化它们，并通过LC/LC/MS/MS确定其蛋白质组成。 AIM 2旨在研究肠内分泌囊泡和红细胞质膜之间的囊泡对接和融合。囊泡运输到红细胞细胞溶胶中的（寄生虫衍生的）Maurer的裂口，红细胞膜似乎是肌动蛋白 - 六体性肌球蛋白介导的。 AIM 3将表征肌动蛋白和肌球蛋白在囊泡形成中的作用，以及肠内分泌囊泡向RBC质膜的运输。在细胞生物学中，将专门的分泌系统的出口和建立在遥远的位置是不寻常的，并且指向寄生虫将宿主细胞“转化”为分泌细胞，以满足感染的红细胞阶段的需求。囊泡形成，运输，对接或融合中关键事件的鉴定可能导致识别可能提供新药物靶标的独特过程或分子。