How bacteria corrupt the host vesicular trafficking:Role of SNARE-like Proteins

描述(申请人提供)：细菌源的传染病已经戏剧性地卷土重来，突显了开发新的治疗工具的紧迫性。然而，需要在细胞和分子水平上更好地了解宿主与病原体的相互作用，以定义新的靶点。我们的长期目标是开发这种新的治疗工具。不同的病原体使用不同的分子机制来穿透宿主细胞并操纵细胞内的囊泡运输。例如，病毒使用的糖蛋白在结构和功能上与介导真核膜融合和囊泡运输的SNARE蛋白相似。对细菌基因组的大规模测序表明，许多细菌也表达与真核细胞中的SNARE融合机制组件同源的膜蛋白。这些类似陷阱的蛋白质可能具有类似的功能，微生物可以利用它们来阻止或促进膜融合。这个项目将测试这样的假设，即细菌陷阱样蛋白与真核细胞陷阱相互作用，操纵膜融合，使之对它们有利。首先，我们将使用两个衣原体和两个军团菌陷阱样蛋白作为我们的模型来探索细菌陷阱样蛋白和哺乳动物陷阱之间的相互作用。接下来，我们将评估细菌陷阱样蛋白在哺乳动物陷阱介导的膜融合中的作用。最后，我们将鉴定和鉴定细菌陷阱样蛋白生物活性结构域的功能。不同病原生物中SNARE样蛋白的存在表明，SNARE基序可能是在进化过程中被选择的，因为它是操纵真核膜融合的有效结构基序，从而有助于病原菌的生存。这样的反复将使我们能够开发出一种共同的策略，针对广泛的细菌陷阱样蛋白。设计能够破坏细菌陷阱状结构域的新细菌疗法应该会逆转融合的阻碍，并允许吞噬小体清除细菌。公共卫生相关性：该研究项目建议确定细胞内细菌是否利用陷阱样蛋白来操纵宿主囊泡运输途径。这些结果将有助于更好地理解含有寄生虫的空泡如何绕过溶酶体的降解，并将有助于揭示寄生虫细胞内生存的机制。此外，建议的研究在开发新的治疗方法以诱导宿主细胞清除细胞内细菌方面具有实际应用价值。

DESCRIPTION (provided by applicant): Infectious diseases of bacterial origin have made a dramatic comeback, highlighting the urgency to develop new therapeutic tools. However, a better understanding of host-pathogen interaction at the cellular and molecular level is needed to define new targets. Our long-term goal is to develop such new therapeutic tools. Different pathogens use a variety of molecular machineries to penetrate host cells and manipulate intracellular vesicular trafficking. For instance, viruses employ glycoproteins, which are structurally and functionally similar to the SNARE proteins that mediate eukaryotic membrane fusion and vesicular trafficking. Large scale sequencing of bacterial genomes has revealed that many bacteria also express membrane proteins with homology to the eukaryotic SNARE fusion machinery components. These SNARE-like proteins might share similar functions and could be used by microorganisms to either block or promote membrane fusion. This project will test the hypothesis that bacterial SNARE-like proteins interact with the eukaryotic SNAREs to manipulate membrane fusion to their advantage. First, we will explore the interaction between bacterial SNARE-like proteins and mammalian SNAREs, using two Chlamydia and two Legionella SNARE-like proteins as our models. Next, we will assess the effect of bacterial SNARE-like proteins on mammalian SNARE- mediated membrane fusion. Finally, we will identify and characterize the functions of the bacterial SNARE-like protein bioactive domains. The presence of SNARE-like proteins in different pathogenic organisms indicates that the SNARE motif may have been selected during evolution because it is an efficient structural motif for manipulating eukaryotic membrane fusion and thus contribute to pathogen survival. Such a recurrence would allow us to develop a common strategy for targeting a wide array of bacterial SNARE-like proteins. Designing new bacterial therapeutics capable of corrupting the bacterial SNARE-like domains should revert the blockage of fusion and allow bacteria clearance by the phagosomes. PUBLIC HEALTH RELEVANCE: This research project proposes to determine whether intracellular bacteria utilize SNARE-like proteins to manipulate host vesicular trafficking pathways. Results will contribute to a better understanding of how parasite-containing vacuoles bypass lysosomal degradation and will shed light on the mechanism of parasitic intracellular survival. Additionally, the proposed studies have practical applications for the development of new therapeutic approaches to induce the clearance of intracellular bacteria by the host cell.