Microneme Function in Toxoplasma

描述（由申请方提供）：专性细胞内原生动物刚地弓形虫可在妊娠期间引起致死性疾病（弓形虫病），或在其他健康人群中引起免疫功能障碍和使人衰弱的眼部病理。寄生虫侵入的快速循环产生在再活化感染期间所见的标志性坏死病变。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，微线粘附复合物TgMIC 2-M2 AP是运动和细胞侵袭机制的关键组成部分。然而，它仍然知之甚少，这些蛋白质如何组装成一个可行的复合物或复合物在体内感染过程中发挥什么作用。此外，与TgMIC 2-M2 AP一起起作用的其他侵袭蛋白的具体贡献仍然不清楚。基于对相关寄生虫的观察，我们的一般假设是，弓形虫微线蛋白有助于感染期间的组织侵入和定殖。我们的具体目标是1）定义与TgMIC 2-M2 AP复合物组装相关的结构域相互作用和事件序列; 2）使用新衍生的敲除和敲低菌株阐明TgMIC 2-M2 AP复合物在感染中的作用;和3）评估在我们最近的蛋白质组学筛选中鉴定的其他新型入侵蛋白对细胞进入和感染的贡献。这些研究将为深入了解弓形虫粘附的分子基础及其在感染和发病机制中的作用提供帮助。由于细胞粘附是寄生虫的一个基本特征，我们预计这些研究可能会导致新的未来机会，中断感染和潜在的改善疾病。

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.