Blockade of host apoptosis by Toxoplasma gondii

描述（由申请人提供）：弓形虫在细胞内生长， 一个独特的寄生物修饰的隔间，寄生空泡（PV）。的 PV与寄主细胞质之间被寄生液泡膜隔开 （PVM）。PVM的一个形态上的独特特征是它的亲密性， 与宿主线粒体和内质网（ER）的联系。 PVM-线粒体缔合由棒状体衍生的介导， ROP 2家族的PVM定位蛋白。的亲密关系 线粒体和PVM表明在寄生虫生物学中的重要功能。 最近的证据表明T.感染gondli的细胞 抗凋亡。线粒体在传递过程中起着核心作用 和执行凋亡刺激。本建议的目的是确定 探讨了T.刚地。鉴于 线粒体在凋亡中的重要性，PVM-线粒体的作用 将检测细胞凋亡阻断中的相关性。凋亡信号是 由半胱氨酸蛋白酶家族传递和执行。的 T的影响。弓形虫感染对caspase的激活和活性的影响 用生物化学的方法来检测。最后，寄生物介体（一个或多个） 宿主细胞凋亡的阻断将使用基因组， 生物化学和遗传学方法。遗传学方法采用了一种新的屏幕 以鉴定和分离T.弓形虫突变体的基础上，他们无法保护 感染的细胞免受凋亡刺激。确定的分子基础 霸王弓形虫介导的细胞凋亡阻断将揭示新的见解， 这种迷人的寄生虫对宿主功能的操控

DESCRIPTION (provided by applicant): Toxoplasma gondii grows in the cell within a unique parasite-modified compartment, the parasitophorous vacuole (PV). The PV is separated from the host cytoplasm by the parasitophorous vacuole membrane (PVM). A morphologically distinctive feature of the PVM is its intimate association with host mitochondria and endoplasmic reticulum (ER). PVM-mitochondrial association is mediated by the rhoptry derived, PVM-localizing proteins of the ROP2 family. The intimate association of mitochondria and the PVM suggests an important function in parasite biology. Recent evidence indicates that T. gondli infected cells are profoundly resistant to apoptosis. Mitochondria play a central role in the transmission and execution of apoptotic stimuli. The aim of this proposal is to identify the molecular basis of the blockade of host apoptosis by T. gondii. Given the importance of mitochondria in apoptosis, the role of PVM-mitochondrial association in the block of apoptosis will be examined. Apoptotic signals are transmitted and executed by a family of cysteine proteases called caspases. The effect of T. gondii infection on caspase activation and activity will be examined using biochemical approaches. Finally, the parasite mediator(s) of the blockade of host apoptosis will be identified using a combination of genomic, biochemical and genetic approaches. The genetic approach employs a novel screen to identify and isolate T. gondii mutants based on their inability to protect the infected cell from apoptotic stimuli. Identifying the molecular basis of the T. gondii mediated blockade of apoptosis will reveal novel insights into the manipulation of host functions by this fascinating parasite.