BIOGENESIS OF RHOPTRIES IN TOXOPLASMA GONDII

描述：在免疫抑制患者中，原虫寄生虫弓形虫 弓形虫可以通过快速入侵、繁殖、 以及宿主细胞的裂解，特别是中枢神经系统的裂解。按顺序 为了入侵和操纵宿主细胞以满足其需要，寄生虫会分泌 三种特殊细胞器--微线体、棒状体和密集细胞器的含量 颗粒。尽管这些细胞器在寄生虫的生存中起着核心作用， 人们对它们形成的机制和途径知之甚少。我们 最近发现，就像在哺乳动物细胞中一样，弓形虫具有高度的 以跨膜蛋白为靶点的通用和识别机制 基于对含酪氨酸的识别的细胞内不同位置 它们的细胞质尾部有氨基酸基序。在一个案例中，证据 提示棒状蛋白ROP2需要这样一个基序来靶向 从一个假定的成熟的棒状体内的前锥体隔间，以及该适配器 识别这些基序的蛋白质与杆状病毒密切相关。 生物发生学。我们建议进一步阐明对蛋白质的需求 制备和分析一系列ROP2和ROP2基因突变体的靶向性研究 并对其齐聚特性进行了研究。在……里面 此外，我们建议使用ROP2突变体作为标记来彻底表征 通过电子显微镜观察，亚细胞分离， 和体外贩运试验，这将大大促进我们的 对杆状病毒生物发生途径和机制的认识 这些目标实质上增加了父母拨款的三个具体目标， 它们将发送给：i)描述杆状病毒之间的分子相互作用 PVM中的蛋白质和宿主细胞蛋白质/细胞器，识别唯一的 针对弓形虫致密颗粒的蛋白质靶向特征，以及III.阐明 新的特点是控制致密的颗粒分泌。通过阐明 棒状病毒生物发生和靶向的机制，一个类似于 具体目标二在父母资助下，针对致密颗粒，建议进行研究 提供了一个关键的窗口，了解杆状病毒蛋白靶向和 棒状蛋白的功能。

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.