BIOGENESIS OF RHOPTRIES IN TOXOPLASMA GONDII

弓形虫中圆形体的生物发生

• 批准号: 6639976
• 负责人: KEITH Alan JOINER
• 金额: $ 3.96万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6639976
• 关键词: Toxoplasma gondii; biosynthesis; electron microscopy; exocytosis; granule; intracellular transport; membrane activity; membrane proteins; microorganism culture; organelles; protein transport; protozoal antigen

DESCRIPTION: In immunosuppressed patients the protozoan parasite Toxoplasma gondii can cause severe tissue destruction by rapid invasion, multiplication, and lysis of host cells, notably those of the central nervous system. In order to invade and manipulate the host cell to its needs the parasite secretes the contents of three specialized organelles - micronemes, rhoptries and dense granules. Despite the central role of these organelles in parasite survival, the mechanisms and pathways by which they are formed are poorly understood. We have recently found that, as in mammalian cells, T. gondii has a highly versatile and discriminatory mechanism for targeting transmembrane proteins to diverse intracellular locations based on the recognition of tyrosine-containing amino acid motifs in their cytoplasmic tails. In one case, the evidence suggested that a rhoptry protein, ROP2, requires such a motif for targeting from a putative pre-rhoptry compartment of mature rhoptries, and that adaptor proteins that recognize these motifs are closely involved in rhoptry biogenesis. We propose to further elucidate the protein requirements for rhoptry targeting by preparing and analyzing a series of mutants of ROP2 and other rhoptry proteins and by characterizing their oligomerization. In addition, we propose to use ROP2 mutants as markers to thoroughly characterize the pre-rhoptry compartment by electron microscopy, subcellular fractionation, and in vitro trafficking assays, which would considerably advance our understanding of the rhoptry biogenesis pathway and mechanisms These goals add substantially to the three specific aims of the parent grant, which are to: I.) Characterize the molecular interactions between rhoptry proteins in the PVM and host cell proteins/organelles, Identify the unique features of protein targeting to T. gondii dense granules, and III.) Elucidate the novel features controlling dense granule secretion. By elucidating the mechanisms of rhoptry biogenesis and targeting, a goal which is analogous to specific aim II in the parent grant for dense granules, the proposed studies provide a critical window into the link between rhoptry protein targeting and rhoptry protein function.

描述：在免疫抑制的患者中，原生动物寄生虫弓形虫 弓形会通过快速侵袭，乘法，造成严重的组织破坏， 和宿主细胞的裂解，尤其是中枢神经系统的细胞。为了 为了侵略和操纵宿主细胞，寄生虫分泌 三个专用细胞器的内容 - 微分，rhoptries和致密 颗粒。尽管这些细胞器在寄生虫生存中的核心作用，但 它们形成的机制和途径知之甚少。我们 最近发现，与哺乳动物细胞一样，T。gondii具有高度 靶向跨膜蛋白的多功能和歧视性机制 根据含酪氨酸的识别的细胞内位置 其细胞质尾部中的氨基酸基序。在一个案例中，证据 提出一种Rhoptry蛋白ROP2需要这样的基序来靶向 从推定的成熟rhoptries的洪流前室和该适配器 识别这些基序的蛋白质与Rhoptry密切相关 生物发生。我们建议进一步阐明 通过准备和分析ROP2的一系列突变体和 其他Rhoptry蛋白质并通过表征其低聚。在 此外，我们建议将ROP2突变体用作标记以彻底表征 通过电子显微镜，亚细胞分馏的前室室室， 并在体外贩运测定法，这将大大推动我们的 理解步骤生物发生途径和机制 这些目标大大增加了父母赠款的三个特定目标： 是：I。）表征了犀牛之间的分子相互作用 PVM中的蛋白质和宿主细胞蛋白/细胞器，识别独特 靶向Gondii致密颗粒的蛋白质的特征，以及III。 这部小说具有控制密集的颗粒分泌的特征。通过阐明 罗普特（Rhoptry）生物发生和靶向机制，一个类似于 拟议研究 提供一个关键的窗口，进入Rhoptry蛋白靶向和 Rhoptry蛋白功能。