Microneme Function in Toxoplasma

描述（由申请人提供）：专性细胞内原生动物刚地弓形虫可在怀孕期间引起致命疾病（弓形虫病）或免疫功能障碍和其他健康人群的眼部病变。寄生虫侵袭的快速周期产生标志性的坏死性病变，在再激活感染期间可见。我们的长期目标是了解粘附及其在寄生虫传播，细胞进入和组织定植中的作用。最近的研究结果表明，微纳米黏附复合物TgMIC2-M2AP是运动和细胞侵袭机制的关键组成部分。然而，人们对这些蛋白质如何组装成一个可行的复合体以及该复合体在体内感染中起什么作用仍然知之甚少。此外，与TgMIC2-M2AP一起起作用的其他入侵蛋白的具体作用仍不清楚。根据对相关寄生虫的观察，我们的一般假设是弓形虫微素蛋白在感染期间有助于组织入侵和定植。我们的具体目标是：1)定义与TgMIC2-M2AP复合物组装相关的结构域相互作用和事件序列；2)利用新获得的敲除和敲除菌株阐明TgMIC2-M2AP复合物在感染中的作用；3)评估我们最近在蛋白质组学筛选中发现的其他新型入侵蛋白对细胞进入和感染的贡献。这些研究将为弓形虫黏附的分子基础及其在感染和发病中的作用提供更深入的认识。由于细胞粘附是寄生虫的基本特征，我们预计这些研究可能会带来新的未来机会，以中断感染并潜在地改善疾病。

DESCRIPTION (provided by the applicant): The obligate intracellular protozoan Toxoplasma gondii can cause lethal disease (toxoplasmosis) during pregnancy or immune dysfunction and debilitating ocular pathology in otherwise healthy people. Rapid cycles of parasite invasion produce the hallmark necrotic lesions seen during reactivated infection. Our long term goal is to understand adhesion and its role in parasite dissemination, cell entry, and tissue colonization. Recent findings indicate that the micronemal adhesive complex TgMIC2-M2AP is a key component of the motility and cell invasion machinery. However, it remains poorly understood how these proteins assemble into a viable complex or what role the complex plays during in vivo infection. Also, the specific contributions of other invasion proteins that function alongside TgMIC2-M2AP remain obscure. Based on observations in related parasites, our general hypothesis is that Toxoplasma microneme proteins contribute to tissue invasion and colonization during infection. Our specific aims are to 1) Define the domain interactions and sequence of events associated with assembly of the TgMIC2-M2AP complex; 2) Elucidate the role of the TgMIC2-M2AP complex in infection using newly derived knockout and knockdown strains; and 3) Assess the contributions of other novel invasion proteins identified in our recent proteomic screen to cell entry and infection. These studies will provide a deeper understanding of the molecular basis of Toxoplasma adhesion and its role in infection and pathogenesis. Because cell adhesion is an essential feature of the parasite, we anticipate these studies may lead to novel future opportunities to interrupt infection and potentially ameliorate disease.