Human pathogenic bacterium induces actin phosphorylation to selectively regulate

人类致病菌诱导肌动蛋白磷酸化选择性调节

• 批准号: 8578739
• 负责人: Hameeda Sultana
• 金额: $ 4.42万
• 依托单位: OLD DOMINION UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8578739
• 关键词: 1-Phosphatidylinositol 3-Kinase; Actins; Address; Affinity; Anaplasma phagocytophilum; Arthropod Vectors; Arthropods; Bacteria; Binding; Binding Proteins; Biological Assay; Black-legged Tick; Bovine Anaplasmosis; Cell Nucleus; Cells; Cytoskeleton; DNA; Data; Electrophoretic Mobility Shift Assay; F-Actin; G Actin; G-Protein-Coupled Receptors; Gene Expression Regulation; Genes; Genetic Transcription; Human; Infection; Ixodes; Life Cycle Stages; Mammals; Mediating; Mediator of activation protein; Medical; Microbe; Modeling; Molecular; Myosin ATPase; Myosin Light Chains; Nuclear; PIK3CG gene; Phosphorylation; Precipitation; Proteins; RNA Polymerase II; Regulation; Rickettsia; Role; Signal Transduction; Specificity; TATA Box; Ticks; Time; Transcription Coactivator; United States; Vector-transmitted infectious disease; neglect; novel; pathogen; pathogenic bacteria; promoter; vector

DESCRIPTION (provided by applicant): Many bacterial pathogens exploit host actin cytoskeleton either during entry/internalization or spread from cell to cell. Pathogen use of the actin cytoskeleton in arthropod vectors has not yet been explored. Using Ixodes scapularis ticks and Anaplasma phagocytophilum (the agent of human granulocytic anaplasmosis) as an infection model, I provide evidence for the first time to show how an obligate intracellular bacterium can exploit the actin cytoskeleton to control arthropod gene transcription for its own benefit. My preliminary results show that A. phagocytophilum induces the phosphorylation of tick actin and subsequently alters the ratio of monomeric/filamentous (G/F)-actin. I also show that A. phagocytophilum-induced actin phosphorylation is dependent on Ixodes PAK1-PI3kinase signaling. A. phagocytophilum-induced actin phosphorylation resulted in increased nuclear G-actin and phosphorylated actin that associated with RNA Polymerase II (RNAPII). Induced actin phosphorylation in the nucleus enhanced binding of TATA-box-binding-protein to RNAPII and caused the selective regulation of salp16, a gene crucial for A. phagocytophilum survival. This project proposal explores to identify the mechanism by which selective regulation of salp16 promoter is mediated upon A. phagocytophilum infection. Additional studies are proposed to identify whether any of the bacterial component(s) or other Ixodes transcriptional activator(s) are involved in this specific gene regulation. Collectively, this study may provide evidence for a novel role of actin phosphorylation during host- pathogen interaction and suggest new strategies to interfere with the life cycle of this obligate intracellular pathogen, and perhaps other Rickettsia-related microbes of medical importance.

描述（由申请人提供）：许多细菌病原体在进入/内化或从一个细胞传播到另一个细胞期间利用宿主肌动蛋白细胞骨架。节肢动物载体中肌动蛋白细胞骨架的病原体用途尚未被探索。我使用肩胛硬蜱和嗜吞噬细胞无形体（人类粒细胞无形体病的病原体）作为感染模型，首次提供证据来证明专性细胞内细菌如何利用肌动蛋白细胞骨架来控制节肢动物基因转录以达到自身利益。我的初步结果表明，A. phagocytophilum 诱导蜱肌动蛋白磷酸化，随后改变单体/丝状 (G/F) 肌动蛋白的比例。我还表明，A. phagocytophilum 诱导的肌动蛋白磷酸化依赖于 Ixodes PAK1-PI3 激酶信号传导。 A. phagocytophilum 诱导的肌动蛋白磷酸化导致核 G 肌动蛋白和与 RNA 聚合酶 II (RNAPII) 相关的磷酸化肌动蛋白增加。细胞核中诱导的肌动蛋白磷酸化增强了 TATA 盒结合蛋白与 RNAPII 的结合，并引起 salp16 的选择性调节，salp16 是嗜吞噬细胞球菌存活的关键基因。该项目提案探讨了确定在嗜吞噬细胞球菌感染时介导 salp16 启动子选择性调节的机制。建议进行额外的研究来确定任何细菌成分或其他硬蜱转录激活剂是否参与这种特定的基因调控。总的来说，这项研究可能为肌动蛋白磷酸化在宿主-病原体相互作用过程中的新作用提供证据，并提出干扰这种专性细胞内病原体以及其他具有医学重要性的立克次体相关微生物生命周期的新策略。