The Role the AAA+ Lon Proteases in Bacterial Pathogenesis

AAA Lon 蛋白酶在细菌发病机制中的作用

• 批准号: 9927592
• 负责人: A. WALI KARZAI
• 金额: $ 46.18万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2022-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9927592
• 关键词: ATP phosphohydrolase; Adaptor Signaling Protein; Bacteria; Binding; Binding Sites; Biological Process; Blood; Borrelia; Borrelia burgdorferi; Cells; Collaborations; Elements; Environment; Escherichia coli; Etiology; Evaluation; Exposure to; Fleas; Gene Expression; Genes; Goals; Growth; Human; In Vitro; Invertebrates; Ixodes; Life; Lyme Disease; Maintenance; Mediating; Orthologous Gene; Pathogenesis; Pathway interactions; Peptide Hydrolases; Physiological; Plague; Play; Proteins; Proteolysis; Proteome; Public Health; Regulation; Research Personnel; Research Project Grants; Role; Signal Transduction; Specificity; Substrate Specificity; System; Testing; Ticks; Type III Secretion System Pathway; Up-Regulation; Virulence; Work; Yersinia; Yersinia pestis; base; cofactor; design; endopeptidase La; enhancing factor; environmental change; feeding; fitness; genetic regulatory protein; human disease; in vivo; insight; member; novel; pathogenic bacteria; proteostasis; quality assurance; response; selective expression; transmission process; vector; vector-borne pathogen

Energy-dependent AAA+ proteases have been implicated in controlling numerous physiologically significant pathways. The Lon AAA+ protease, which is conserved from bacteria to humans, has emerged as key contributor to the capacity of the cell to adapt to its ever-changing growth environment. Lon protease play a fundamental role in maintaining the ideal concentration of key regulatory proteins, and in re-sculpting the proteome by removing unfolded, aberrant, or damaged proteins in response to internal and external signals. Knowing how this versatile AAA+ protease and its cofactor(s) select target substrates for degradation is crucial to our understanding of its biological functions. Recent studies have provided compelling evidence to demonstrate that the Lon AAA+ proteases play critical roles in the regulation of virulence gene expression in a number of pathogenic bacteria. The long-term goal of this proposal is to establish the role of the AAA+ Lon proteases in the pathogenesis of bacteria that are required to adapt to environmental changes during their transmission from invertebrate vectors to mammalian hosts. The two specific aims of the proposal are designed to guide us in studies of two vector borne pathogens, Yersinia pestis, transmitted by fleas, and Borrelia burgdorferi, transmitted by ticks. Our aims are motivated by the hypothesis that ATP-fueled Lon proteases facilitate important physiological transitions by selectively removing key regulatory proteins surplus unwanted substrates. Further, we hypothesize that Lon protease selectivity is mediated by specificity enhancing factors (adaptor proteins) or selective expression of unique Lon orthologs with distinct substrate specificities. In Aim I, we will focus on the role and regulation of Lon protease in Yersinia pestis, the causative agent of plague, during the key physiological transition resulting in expression of the type III secretion system. We will focus particularly on the discovery and characterization of a novel and much sought after specificity-enhancing factor for Lon protease. We will investigate the mechanism by which this novel adaptor protein regulates substrate selection and degradation by Lon protease. In Aim II, we will focus on the role and regulation of Lon proteases in Borrelia burgdorferi, the etiological agent of Lyme diseases, with special focus on the unusual occurrence of two Lon proteases (Bb-Lon-1 and Bb-Lon-2), of which the former is expressed in blood. We will examine the merits of the hypothesis that the Bb-Lon-1 has a distinct substrate range and specificity, uniquely different from the canonical Lon proteases of other bacteria, including the Bb-Lon-2 protease. We will determine the substrate range and specificity of Borrelia Lon proteases and elucidate how Bb-Lon-1 remodels the spirochetal proteome and maintains ideal concentration of key regulatory proteins to facilitate the physiological transition triggered by exposure to mammalian blood. A detailed understanding of the substrate range and specificity of Lon proteases, and how remodeling of the bacterial proteome by Lon contributes to the fitness, survival, and virulence of bacteria will provide significant new insight into the principles of general and selective proteolysis.

能量依赖性AAA+蛋白酶参与控制许多 重要的生理途径。Lon AAA+蛋白酶从细菌到人类都是保守的，已经成为细胞适应其不断变化的生长环境的能力的关键贡献者。离子蛋白酶发挥作用 在维持关键调节蛋白的理想浓度方面起着重要作用， 通过去除未折叠的、异常的或受损的蛋白质来重新塑造蛋白质组， 内部和外部信号了解这种多功能AAA+蛋白酶及其辅因子如何选择 降解的靶底物对于我们理解其生物学功能至关重要。 最近的研究提供了令人信服的证据，证明Lon AAA+蛋白酶发挥作用， 在许多致病细菌中，在调节毒力基因表达中起关键作用。 该提案的长期目标是确定AAA+ Lon蛋白酶在细胞内的作用。 细菌的致病机制，需要适应环境的变化，在他们的 从无脊椎动物传播到哺乳动物宿主。该提案的两个具体目标 旨在指导我们研究两种媒介传播的病原体，鼠疫耶尔森氏菌， 跳蚤和伯氏疏螺旋体通过蜱传播。我们的目标是基于这样一种假设 以ATP为燃料的Lon蛋白酶通过选择性地 去除关键调节蛋白多余的不需要的底物。此外，我们假设朗 蛋白酶选择性由特异性增强因子（衔接蛋白）或选择性增强因子介导。 具有不同底物特异性的独特Lon直系同源物的表达。在目标I中，我们将重点关注 Lon蛋白酶在鼠疫致病菌耶尔森氏菌中的作用和调节， 在导致III型分泌系统表达的关键生理转变期间。 我们将特别关注一部小说的发现和人物塑造， Lon蛋白酶的特异性增强因子。我们将研究这一机制， 一种新的衔接蛋白调节Lon蛋白酶的底物选择和降解。在Aim II中，我们 将集中在Lon蛋白酶在伯氏疏螺旋体中的作用和调节， 莱姆病的病原体，特别关注两种Lon蛋白酶（Bb-Lon-1）的不寻常发生 和Bb-Lon-2），其中前者在血液中表达。我们将研究 假设Bb-Lon-1具有不同的底物范围和特异性， 来自其它细菌的典型Lon蛋白酶，包括Bb-Lon-2蛋白酶。我们将 确定疏螺旋体Lon蛋白酶的底物范围和特异性，并阐明Bb-Lon-1 重塑螺旋体蛋白质组并维持关键调节蛋白的理想浓度 以促进通过暴露于哺乳动物血液而触发的生理转变。详细 了解Lon蛋白酶的底物范围和特异性，以及如何重塑 Lon的细菌蛋白质组有助于细菌的适应性，存活和毒性 将提供重要的一般和选择性蛋白水解的原则新的见解。