Mechanism of Peptide Signaling in Bacillus Subtilis

枯草芽孢杆菌中肽信号转导机制

• 批准号: 6474720
• 负责人: BETH ANN LAZAZZERA
• 金额: $ 32.84万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6474720
• 关键词: Bacillus subtilis; bacterial proteins; biological signal transduction; laboratory rabbit; peptides; permease; phosphorylation; protein binding; protein biosynthesis; protein protein interaction; protein structure function; receptor; transport proteins

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to understand a novel mechanism of peptide signaling in Gram-positive bacteria using Competence and Sporulation Factor (CSF) of Bacillus subtilis as a model system. CSF is a member of an emerging class of signaling peptides that function intracellularly. Previously, signaling peptides had been thought to function only through membrane receptors, due to the presence of peptidases inside the cell. However, our studies have shown that CSF, an unmodified five amino acid peptide, is transported into the cell where it functions intracellularly to regulate gene expression. Peptide signals, like CSF, are used by Gram-positive bacteria to monitor their population density (i.e. quorum sensing). Quorum sensing in bacteria regulates such medically important processes as virulence and biofilm development. Therefore, functions regulated by peptide signaling pathways in the medically important Gram-positive bacteria are potential drug targets. We hope that, by understanding the mechanism of signaling by CSF in B. subtilis, we will be able to identify additional intracellular functioning signaling peptides in other bacteria. We have proposed experiments to understand the mechanism of production and response to CSF. The precursor protein for CSF is secreted through the general Sec-dependent export pathway and then processed extracellularly. We have isolated a mutant that appears to be defective in this extracellular processing activity. We have proposed genetic and biochemical experiments to characterize the role of protein defective in this mutant in CSF production. Mature CSF is imported by a non-specific oligopeptide permease (Opp), homologues of which exist in many bacteria. Experiments are proposed to determine the binding affinity of CSF for Opp and whether other peptides compete with CSF for binding to Opp. Once inside the cell, CSF appears to have at least three intracellular receptors. We have proposed experiments to identify the intracellular receptors of CSF and to understand how CSF interacts with these receptors. CSF regulates the activity of two phosphatases that dephosphorylate response regulators. These phosphatases are intriguing as they show similarity to the widespread tetratrico peptide repeat (TPR) protein domain family. The proposed experiments should elucidate the mechanism of signaling by this novel class of intracellular function peptides.

描述（由申请人提供）：该提案的长期目标是 了解革兰氏阳性细菌中肽信号传导的新机制 使用枯草芽孢杆菌的能力和孢子形成因子（CSF）作为模型 系统。 CSF 是一类新兴信号肽的成员， 在细胞内发挥作用。此前，信号肽被认为 由于肽酶的存在，仅通过膜受体发挥作用 细胞内。然而，我们的研究表明，CSF，未经修饰的五 氨基酸肽，被转运到细胞中发挥作用 细胞内调节基因表达。肽信号，如 CSF， 革兰氏阳性菌用来监测其种群密度（即群体密度） 感测）。细菌中的群体感应调节如此重要的医学意义 毒力和生物膜形成等过程。因此，功能调节 通过医学上重要的革兰氏阳性细菌中的肽信号传导途径 是潜在的药物靶点。我们希望通过了解其机制 通过枯草芽孢杆菌中 CSF 的信号传导，我们将能够识别其他 其他细菌中的细胞内功能信号肽。我们有 提出了实验来了解产生和响应的机制 脑脊液。脑脊液的前体蛋白是通过一般细胞分泌的 Sec依赖性输出途径，然后在细胞外加工。我们有 分离出一种在这种细胞外加工中似乎有缺陷的突变体 活动。我们提出了遗传和生化实验来表征 该突变体中蛋白质缺陷在脑脊液产生中的作用。成熟的脑脊液是 由非特异性寡肽通透酶 (Opp) 输入，其同源物 存在于许多细菌中。建议进行实验以确定结合 CSF 对 Opp 的亲和力以及其他肽是否与 CSF 竞争结合 到奥普。一旦进入细胞，脑脊液似乎至少有三个细胞内 受体。我们提出了鉴定细胞内受体的实验 脑脊液并了解脑脊液如何与这些受体相互作用。 CSF 监管 两种磷酸酶的活性，使反应调节剂去磷酸化。 这些磷酸酶很有趣，因为它们与广泛存在的磷酸酶相似。 四肽重复 (TPR) 蛋白结构域家族。拟议的实验 应该阐明这类新型的信号传导机制 细胞内功能肽。