Molecular Mechanism of Pathogenesis

发病机制的分子机制

• 批准号: 6802631
• 负责人: JACK E DIXON
• 金额: $ 37.5万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-05-15 至 2009-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6802631
• 关键词: Agrobacterium; Pseudomonas; Yersinia pestis; bacterial cytopathogenic effect; bacterial proteins; biological signal transduction; cysteine endopeptidases; enzyme substrate; fatty acylation; green fluorescent proteins; hypersensitivity; immunoprecipitation; mass spectrometry; myristates; phosphorylation; posttranslational modifications; protein localization; protein structure function; proteolysis; virulence; yeast two hybrid system

DESCRIPTION (provided by applicant): A Yersinia effector known as YopT and a Pseudomonas avirulence protein known as AvrPphB define a family of 19 proteins involved in bacterial pathogenesis. We show that both YopT and AvrPphB are cysteine proteases, and their proteolytic activities are dependent upon the invariant C/HID residues conserved in the entire YopT family. YopT cleaves the post-translationally modified Rho GTPases near their carboxyl termini, releasing them from the membrane. This leads to the disruption of actin cytoskeleton in host cells. The proteolytic activity of AvrPphB is essential for autoproteolytic cleavage of an AvrPphB precursor as well as for eliciting the hypersensitive response in plants. The biochemical functions of most avirulence (Avr) proteins are unknown. This proposal focuses on developing a molecular understanding of how the AvrPphB family of proteins is activated and post-translationally modified. In addition, efforts to identify the substrate(s) for AvrPphB are described. Finally, we propose to obtain the x-ray structure of AvrPphB complexed with a peptide substrate. These experiments will provide us with new insights into the molecular mechanism of pathogenesis.

描述（由申请人提供）：称为 YopT 的耶尔森氏菌效应蛋白和称为 AvrPphB 的假单胞菌无毒蛋白定义了涉及细菌发病机制的 19 个蛋白家族。我们发现 YopT 和 AvrPphB 都是半胱氨酸蛋白酶，它们的蛋白水解活性取决于整个 YopT 家族中保守的不变 C/HID 残基。 YopT 在羧基末端附近裂解翻译后修饰的 Rho GTPases，将其从膜上释放出来。这导致宿主细胞中肌动蛋白细胞骨架的破坏。 AvrPphB 的蛋白水解活性对于 AvrPphB 前体的自身蛋白水解裂解以及在植物中引发过敏反应至关重要。大多数无毒 (Avr) 蛋白的生化功能尚不清楚。该提案的重点是从分子角度理解 AvrPphB 蛋白家族如何被激活和翻译后修饰。此外，还描述了鉴定 AvrPphB 底物的努力。最后，我们建议获得与肽底物复合的 AvrPphB 的 X 射线结构。这些实验将为我们提供关于发病机制的分子机制的新见解。