Flagellar Motor Biogenesis in Polarly-Flagellated Bacterial Pathogens

极鞭毛细菌病原体中的鞭毛运动生物发生

• 批准号: 9268571
• 负责人: DAVID R HENDRIXSON
• 金额: $ 47.37万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-02-15 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9268571
• 关键词: ATP phosphohydrolase; Bacteria; Biogenesis; Biological; Biological Models; Campylobacter; Campylobacter jejuni; Cell division; Cells; Cellular biology; Characteristics; Complex; Data; Disease; Electrons; Engineering; Environment; Escherichia coli; Flagella; Gene Expression; Genes; Genetic Transcription; Goals; Helicobacter; Helicobacter pylori; Human; Infection; Link; Mastigophora; Methodology; Microbial Biofilms; Modernization; Molecular; Motor; Mutagenesis; Nature; Orthologous Gene; Pathogenesis; Pathway interactions; Process; Property; Proteins; Pseudomonas; Pseudomonas aeruginosa; Regulation; Research; Rotation; Salmonella; Signal Transduction; Signal Transduction Pathway; Stimulus; Structure; Swimming; System; Technology; Torque; Type III Secretion System Pathway; Vibrio; Vibrio cholerae; Virulence; Work; appendage; cell motility; insight; microbial; nanomachine; pathogen; pathogenic bacteria; programs; protein-histidine kinase; public health relevance

 DESCRIPTION (provided by applicant): Flagella are natural rotary motors that promote swimming motility required by many bacterial pathogens to navigate environments, infect hosts to promote disease, and promote biofilm formation. Compared to peritrichous bacterial pathogens such as E. coli and Salmonella species, many significant pathogens including Campylobacter jejuni, Vibrio cholerae, Helicobacter pylori, and Pseudomonas aeruginosa produce only a very limited number of flagellar motors specifically at poles of a bacterial cell. Furthermore, these polar flagellar motors promote higher torque and greater velocity of motility compared to flagellar motors of peritrichous bacteria. Thus, alternative paradigms must exist to account for how polar flagellar motors form and function in bacterial pathogens. We have explored flagellar biogenesis in C. jejuni to discover new paradigms for how polarly-flagellated bacterial pathogens regulate flagellar gene transcription, spatially and numerically regulate flagellar biogenesis, and alter flagellar motor structure to power flagellar rotation for motility.We also found evidence for general conservation of these mechanisms in a range of polarly-flagellated pathogens. In this proposal, we will continue to use C. jejuni as a model system to understand how the flagellar motor, which is a universal virulence and colonization determinant, forms and functions in a wide range of polarly-flagellated bacterial pathogens. Our work will also continue to reveal how the bacterial flagellum functions beyond motility to influence signal transduction pathways, spatial organization of the bacterial cell, and cell division in C. jejuni. n Aim 1, we will examine how conserved flagellar two-component regulatory systems (TCSs) of polarly-flagellated pathogens detect formation of the flagellar type III secretion system (T3SS) and surrounding ring structures to initiate signal transduction required for flagellar gene transcription. We will also exploit the natural engineering of T3SS formation to activation of the C. jejuni flagellar TCS to determine molecular requirements of proteins to form T3SSs in bacterial pathogens. In Aim 2, we will explore how the conserved FlhG ATPase of polar flagellates and a possible unusual flagellar C ring composition function together to numerically regulate flagellar biogenesis and spatially control cell division in C. jejuni. In Aim 3, we will exploit mutagenesis and electron cryotomography technologies to decipher the ordered biosynthetic pathway for formation of flagellar disk appendages, which are required for powering flagellar rotation and creation of a functional polar flagellar motor. Accomplishment of these aims will promote new insights for how: 1) TCSs detect and perceive stimuli for initiation of signal transduction required for flagellar gene expression; 2) conserved proteins initiate T3SS formation in bacterial pathogens; 3) bacteria numerically regulate polar flagellar motor biogenesis; 4) flagellar proteins are used in alternate biological activities such as signal transduction, cell division, and spatial organization of the cell; 5) polarly-flagellated pathogens employ disk appendages to diversify flagellar structure and power flagellar rotation to generate torque resulting in high velocities of motility.

 描述（由申请人提供）：鞭毛是天然的旋转马达，可促进许多细菌病原体在环境中导航、感染宿主以促进疾病和促进生物膜形成所需的游泳运动。与大肠杆菌和沙门氏菌等毛周细菌病原体相比，许多重要的病原体（包括空肠弯曲杆菌、霍乱弧菌、幽门螺杆菌和铜绿假单胞菌）仅产生非常有限数量的鞭毛马达，特别是在细菌细胞的两极。此外，与周毛细菌的鞭毛马达相比，这些极鞭毛马达可促进更高的扭矩和更大的运动速度。因此，必须存在替代范式来解释极鞭毛马达如何在细菌病原体中形成和发挥作用。我们探索了空肠弯曲菌的鞭毛生物发生，以发现极性鞭毛细菌病原体如何调节鞭毛基因转录、空间和数值调节鞭毛生物发生以及改变鞭毛运动结构以驱动鞭毛旋转以实现运动的新范例。我们还发现了这些机制在一系列极性鞭毛病原体中普遍保守的证据。在本提案中，我们将继续使用空肠弯曲菌作为模型系统，以了解鞭毛运动（一种普遍的毒力和定植决定因素）如何在各种极性鞭毛细菌病原体中形成和发挥作用。我们的工作还将继续揭示空肠弯曲菌中细菌鞭毛的功能如何超越运动，影响信号转导途径、细菌细胞的空间组织和细胞分裂。在目标 1 中，我们将研究极性鞭毛病原体的保守鞭毛双组分调节系统 (TCS) 如何检测鞭毛 III 型分泌系统 (T3SS) 和周围环状结构的形成，以启动鞭毛基因转录所需的信号转导。我们还将利用 T3SS 形成的自然工程来激活空肠弯曲菌鞭毛 TCS，以确定细菌病原体中形成 T3SS 的蛋白质的分子需求。在目标 2 中，我们将探索极鞭毛虫的保守 FlhG ATP 酶和可能不寻常的鞭毛 C 环组成如何共同发挥作用，以数值调节空肠弯曲菌中的鞭毛生物发生和空间控制细胞分裂。在目标 3 中，我们将利用诱变和电子冷冻断层扫描技术来破译鞭毛盘附属物形成的有序生物合成途径，这是为鞭毛旋转提供动力和创建功能性极鞭毛马达所必需的。这些目标的实现将促进对以下方面的新见解：1）TCS 检测和感知刺激，以启动鞭毛基因表达所需的信号转导； 2）保守蛋白启动细菌病原体中T3SS的形成； 3）细菌以数字方式调节极鞭毛运动生物发生； 4）鞭毛蛋白用于替代生物活动，例如信号转导、细胞分裂和细胞的空间组织； 5) 极鞭毛病原体 利用圆盘附属物使鞭毛结构多样化，并为鞭毛旋转提供动力以产生扭矩，从而产生高速运动。