Vesicle targeting in Plasmodium falciparum

描述(申请人提供)：恶性疟原虫每年导致100多万人死于疟疾，是全球社会面临的最重大的公共卫生挑战之一。血液期恶性疟原虫的分泌途径在介导疟疾的病理过程中起着关键作用，它将细胞黏附的配体运送到感染的红细胞表面，并将红细胞入侵的配体运送到寄生虫内的特化细胞器。然而，恶性疟原虫分泌的许多方面都知之甚少，特别是蛋白质输出到红细胞膜表面和红细胞质中的膜结合细胞器，这是恶性疟原虫生物学上独有的运输步骤。此外，关于恶性疟原虫途径中分泌细胞器的数量和性质的基本问题仍然没有答案。这项应用的广泛目标是全面定义恶性疟原虫分泌途径的基本组织，并阐明囊泡靶向性在蛋白质运输到恶性疟原虫特有的膜结合细胞器中的作用。T-SNARES是一种控制囊泡融合特异性的膜结合蛋白，将被用作细胞器特异性标记，以填补我们知识库中的这些关键空白。我们已经在恶性疟原虫基因组中鉴定了几个假定的T-陷阱，并确定至少有一个T-陷阱被输出到出现在感染恶性疟原虫的红细胞胞浆中的独特细胞器中，并介导蛋白质向红细胞表面的运输。恶性疟原虫t-陷阱的定位和靶向信号的研究将在以下特定目标下进行：1.建立恶性疟原虫t-陷阱的序列和位置。2.了解PfSyns靶向毛雷氏裂隙的分子基础。将使用一系列分子、细胞和生化工具来完成这些目标，包括免疫荧光显微镜、亚细胞分离和表位标记。这项研究具有重要意义，因为这将是恶性疟原虫T型圈套和囊泡靶向的首次研究，并可能有助于澄清长期以来对恶性疟原虫分泌途径基本结构的争议。通过重点研究恶性疟原虫独特的分泌物成分，我们的目标是为未来新的预防和控制措施的发展确定目标。

DESCRIPTION (provided by applicant): Plasmodium falciparum parasites cause over 1 million deaths from malaria each year and represent one of the most significant public health challenges facing the global community. The secretory pathway of blood- stage P. falciparum parasites plays a key role in mediating the pathology of malaria, transporting cyto-adherent ligands to the surface of infected erythrocytes and erythrocyte invasion ligands to specialized organelles within the parasite. However, many aspect of P. falciparum secretion are poorly understood, particularly the export of proteins to the erythrocyte surface and membrane-bound organelles within the erythrocyte cytosol, a transport step that is unique to P. falciparum biology. Furthermore, fundamental questions about the number and nature of secretory organelles in the P. falciparum pathway remain unanswered. The broad objective of this application is to comprehensively define the basic organization of the P. falciparum secretory pathway and to clarify the role of vesicle targeting in protein transport to membrane-bound organelles that are unique to P. falciparum. t-SNAREs, membrane bound proteins that control the specificity of vesicle fusion, will be used as organelle-specific markers to fill these crucial gaps in our knowledge base. We have identified several putative t-SNAREs in the P. falciparum genome and established that at least one of these is exported to unique organelles that appear in the cytosol of P. falciparum infected erythrocytes and mediate protein transport to the erythrocyte surface. The localization of and targeting signals in P. falciparum t-SNAREs will be investigated under the following specific aims: 1. Establish the sequence and location of the P. falciparum t-SNAREs. 2. Understand the molecular basis ofPfSynS targeting to the Maurer's clefts. An array of molecular, cellular and biochemical tools will be used to complete these aims, including immunofluorescence microscopy, sub-cellular fractionation and epitope tagging. This research is significant because it will be the first study of t-SNAREs and vesicle targeting in P. falciparum and may help clarify long- standing disputes about the basic structure of the P. falciparum secretory pathway. By focusing on elements of P. falciparum secretion that are unique to this organism, we aim to identify targets for the future development of novel prevention and control measures.