Manipulation of the host NF-kappa B pathway by Toxopla

弓形虫对宿主 NF-κ B 通路的操纵

• 批准号: 6931074
• 负责人: Robert Molestina
• 金额: $ 5.54万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6931074
• 关键词: I kappa B beta; SDS polyacrylamide gel electrophoresis; Toxoplasma gondii; apoptosis; cytogenetics; enzyme activity; gene expression; high throughput technology; host organism interaction; immunoprecipitation; mass spectrometry; matrix assisted laser desorption ionization; nuclear factor kappa beta; parasite infection mechanism; phosphorylation; postdoctoral investigator; protein kinase; protein protein interaction; proteomics; two dimensional gel electrophoresis

DESCRIPTION (provided by applicant): Toxoplasma gondii is an obligate intracellular protozoan parasite, which causes opportunistic disease in immunodeficient individuals and congenital disease in newborns. T. gondii is widely regarded as one of the most successful parasites on earth because of its broad host range and capability to establish an asymptomatic life-long chronic infection in immunocompetent populations. One of the strategies used by T. gondii to avoid destruction by the infected host cell is the inhibition of apoptosis. Studies performed by the candidate have shown that T. gondii induces a survival response in infected cells via NF-kappa B-dependent up-regulation of anti-apoptotic genes. Remarkably, activation of the NF-kappa B pathway by T. gondii occurs through an unconventional mechanism, which is independent of the host I-kappa B kinase (IKK). In addition, the evidence suggests the presence of a parasite-derived factor(s) capable of hijacking and phosphorylating I-kappa B. Identification of this factor(s) would provide insight into the modulation of host cell signaling events by Toxoplasma and reveal potential therapeutic targets. The proposed studies in this proposal will apply biochemical and molecular genetic approaches to characterize the putative I-kappa B kinase activity in T. gondii and address the following hypothesis: "Toxoplasma gondii manipulates the NF-kappa B pathway of the host cell by recruiting and phosphorylating I-kappa B via a parasite encoded factor(s) that can function autonomously from host IKK." To fulfill this hypothesis, the applicant will: (1) determine the activity of a parasite kinase capable of phosphorylating I-kappa B in subcellular fractions of T. gondii; and (2) identify protein candidates in T. gondii with I-kappa B kinase activity by proteomic and genomic analyses.

描述（申请人提供）：弓形虫是一种专性细胞内原生动物寄生虫，可引起免疫缺陷个体的机会性疾病和新生儿的先天性疾病。T.弓形虫被广泛认为是地球上最成功的寄生虫之一，因为它的宿主范围广泛，并且能够在免疫功能正常的人群中建立无症状的终身慢性感染。T.避免被感染的宿主细胞破坏的弓形虫是抑制细胞凋亡。候选人进行的研究表明，T。弓形虫通过NF-κ B依赖性上调抗凋亡基因诱导感染细胞的存活应答。值得注意的是，T.弓形虫感染是通过一种非常规机制发生的，它不依赖于宿主I-κ B激酶（IKK）。此外，证据表明存在能够劫持和磷酸化I-κ B的寄生虫衍生因子。该因子的鉴定将提供对弓形虫调节宿主细胞信号传导事件的深入了解，并揭示潜在的治疗靶点。本研究将应用生物化学和分子遗传学方法来表征T细胞中推定的I-κ B激酶活性。刚地弓形虫操纵宿主细胞的NF-κ B途径，其通过寄生虫编码的因子募集和磷酸化I-κ B，所述因子可以自主地从宿主IKK起作用。“为了实现这一假设，申请人将：（1）确定能够磷酸化T细胞亚细胞组分中I-κ B的寄生虫激酶的活性。gondii;（2）鉴定T.通过蛋白质组学和基因组学分析，确定了具有I-κ B激酶活性的弓形虫。