IQGAP1 in microbial pathogenesis

IQGAP1 在微生物发病机制中的作用

• 批准号: 7898607
• 负责人: Christopher A French
• 金额: $ 44.5万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-23 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7898607
• 关键词: Actins; Automobile Driving; Bacteria; Be++ element; Beryllium; Binding; Binding Proteins; Biology; CLIP-170 gene; Calmodulin; Categories; Cell-Cell Adhesion; Cells; Comprehension; Confocal Microscopy; Couples; Coupling; Cytoskeleton; DNA Sequence Rearrangement; Data; Diagnosis; Dominant-Negative Mutation; E-Cadherin; Elements; Eukaryotic Cell; Family; Guanosine Triphosphate Phosphohydrolases; Immune response; Individual; Infection; Invaded; Life; Link; Measures; Mediating; Microbe; Microtubules; Molecular; Morphology; National Institute of Allergy and Infectious Disease; Pathogenesis; Peptides; Phagocytes; Phagocytosis; Proteins; Regulation; Role; Salmonella; Salmonella infections; Scaffolding Protein; Signal Pathway; Signal Transduction; Signaling Molecule; Small Interfering RNA; Testing; Vaccine Therapy; Vaccines; Vacuole; base; cell motility; cellular imaging; effective therapy; immunocytochemistry; inhibitor/antagonist; macrophage; microbial; mutant; overexpression; pathogen; rho; trafficking; uptake

Pathogens have developed sophisticated mechanisms to enter cells, evade destruction inside the eukaryotic cell and multiply. The cytoskeleton of the host cell is a common target that is manipulated by bacteria to facilitate infection. Invasive bacteria control the host cell's cytoskeleton to expedite uptake into cells that are normally nonphagocytic and to evade phagocytosis and destruction. The major cytoskeletal elements, particularly actin and microtubules, associate with and are regulated by several proteins. This proposal focuses on IQGAP1, which regulates the cytoskeleton both directly by binding actin and indirectly by interacting with a number of targets, including Cdc42, Rac1 and the microtubule-binding protein CLIP-170. We observed that IQGAP1 has a fundamental role in Cdc42 cytoskeletal function and cell motility. Based on these data we hypothesize that IQGAP1 is an integral component of the cytoskeletal alterations induced by some pathogenic microbes. This proposal focuses on Salmonella. The Specific Aims are: (1) To test the hypothesis that IQGAP1 is an element of the mechanism by which Salmonella enter cells, we shall determine whether IQGAP1 modulates Salmonella invasion by coupling Cdc42/Rac1 to the actin cytoskeleton. Analysis will be performed using mutant and dominant negative IQGAP1 constructs and a specific inhibitor peptide. (2) To test the hypothesis that IQGAP1 participates in phagocytosis and intracellular trafficking of bacteria, uptake and trafficking of Salmonella will be assessed in macrophages in which IQGAP1 function has been manipulated with dominant negative constructs, overexpression and specific knockdown. These studies should indicate whether IQGAP1 participates in Salmonella infection. In addition, the data are likely to enhance our comprehension of Cdc42 and Rac1 in Salmonella pathogenesis, contributing to an understanding of Salmonella biology. Elucidation of the mechanisms of pathogen-host interactions could reveal new targets for diagnosis, therapy and vaccines.

病原体已开发出复杂的机制，可以进入细胞，逃避真核细胞内的破坏并乘以繁殖。宿主细胞的细胞骨架是一个常见靶标，被细菌操纵以促进感染。侵入性细菌控制宿主细胞的细胞骨架，以加快摄取通常非吞噬细胞并逃避吞噬作用和破坏的细胞。主要的细胞骨架元素，尤其是肌动蛋白和微管，与几种蛋白质相关并调节。该提案的重点是IQGAP1，它通过与包括CDC42，RAC1和微管结合蛋白夹170的许多靶标相互作用，直接通过结合肌动蛋白并间接调节细胞骨架。我们观察到IQGAP1在Cdc42细胞骨架功能和细胞运动中具有基本作用。基于这些数据，我们假设IQGAP1是某些致病微生物诱导的细胞骨架改变的组成部分。该提议着重于沙门氏菌。具体目的是：（1）检验IQGAP1是沙门氏菌进入细胞的机制的元素的假设，我们将确定IQGAP1是否通过将CDC42/RAC1偶联到肌动蛋白Cytoskettoskeleton来调节沙门氏菌入侵。分析将使用突变体和显性负IQGAP1构建体和特定抑制剂肽进行。 （2）为了检验IQGAP1参与细菌的吞噬作用和细胞内运输的假设，将在巨噬细胞中评估沙门氏菌的吸收和运输，其中IQGAP1功能已被主要的负面构建体，过表达和特定的敲低。这些研究应表明IQGAP1是否参与沙门氏菌感染。此外，数据可能会增强我们对沙门氏菌发病机理中CDC42和RAC1的理解，从而有助于了解沙门氏菌生物学。阐明病原体宿主相互作用机制可以揭示诊断，治疗和疫苗的新靶标。