Cytoskeletal machinery driving invasion by the human pathogen, Toxoplasma gondii.

项目摘要： 地球上大约有20%的人永久感染了单细胞寄生虫， 弓形虫T.弓形虫是先天性神经缺陷的主要原因之一， 人，以及用于免疫受损个体中的破坏性机会性感染的药剂。 眼弓形虫病是最常见的视网膜感染之一，可导致失明。作为 专性胞内寄生虫T.弓形虫必须首先侵入宿主细胞才能复制。在 初步研究发现，T.刚地，圆锥体，与 大大削弱了入侵。这是入侵的一个方面，还没有被探讨，如前所述。 关于侵袭的工作主要集中在肌动球蛋白运动复合体的调节和活动上 和蛋白质从专门的膜结合细胞器分泌。为了探索这个新方向，我们 提出了两个互补的目的：（a）确定圆锥体在宿主细胞侵袭中的功能（Aim 1），和（B）阐明如何构建这种新的细胞骨架复合物（目的2）。利用变种人， 已经产生，目标1将确定锥状体是否通过分泌，运动， 在附着期间直接辅助寄生虫和宿主细胞之间的物理相互作用，或 克服宿主细胞的皮层张力。目标2将识别和表征结构 通过整合基因发现与结构和功能分析的圆锥体的决定因素。我们 将结合联合收割机最先进的成像、生物物理、生物化学和进化方法。这 全面的战略将大大提高我们在这一独特的环境中识别新组件的能力。 作为药物靶点。

Project Summary: Approximately 20% of the people on Earth are permanently infected with the unicellular parasite, Toxoplasma gondii. T. gondii is one of the leading causes of congenital neurological defects in humans, and an agent for devastating opportunistic infections in immunocompromised individuals. Ocular toxoplasmosis is one of the most common retinal infections and can lead to blindness. As an obligate intracellular parasite, T. gondii must first invade cells of its host in order to replicate. In the preliminary study, we found that the disruption of an iconic structure in T. gondii, the conoid, is linked to drastically impaired invasion. This is an aspect of invasion that has not been explored, as previous work on invasion has mainly centered on the regulation and activity of the actomyosin motor complex and protein secretion from specialized membrane-bound organelles. To explore this new direction, we propose two complementary aims to (a) determine the function of the conoid in host cell invasion (Aim 1), and (b) elucidate how this novel cytoskeletal complex is constructed (Aim 2). Using the mutants we have generated, Aim 1 will determine whether the conoid facilitates invasion by secretion, motility, directly assisting the physical interaction between the parasite and the host cell during attachment, or overcoming the cortical tension of the host cell. Aim 2 will identify and characterize structural determinants of the conoid by integrating gene discovery with structural and functional analyses. We will combine state of the art imaging, biophysical, biochemical, and evolutionary approaches. This comprehensive strategy will greatly enhance our ability to identify novel components in this unique structure as drug targets.