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

描述（由申请人提供）：细菌来源的传染病已经戏剧性地卷土重来，突出了开发新治疗工具的紧迫性。然而，需要在细胞和分子水平上更好地理解宿主-病原体相互作用，以确定新的靶标。我们的长期目标是开发这种新的治疗工具。不同的病原体使用多种分子机制穿透宿主细胞并操纵胞内囊泡运输。例如，病毒利用糖蛋白，其在结构和功能上类似于介导真核细胞膜融合和囊泡运输的SNARE蛋白。细菌基因组的大规模测序已经揭示，许多细菌也表达与真核SNARE融合机制组分具有同源性的膜蛋白。这些SNARE样蛋白可能具有相似的功能，并可被微生物用于阻止或促进膜融合。这个项目将测试假设，即细菌SNARE样蛋白与真核SNARE相互作用，操纵膜融合，以他们的优势。首先，我们将探索细菌SNARE样蛋白和哺乳动物SNARE之间的相互作用，使用两个衣原体和两个军团菌SNARE样蛋白作为我们的模型。接下来，我们将评估细菌SNARE样蛋白对哺乳动物SNARE介导的膜融合的影响。最后，我们将鉴定和表征细菌SNARE样蛋白生物活性结构域的功能。SNARE样蛋白在不同病原生物中的存在表明SNARE基序可能在进化过程中被选择，因为它是操纵真核生物膜融合的有效结构基序，从而有助于病原体存活。这种复发将使我们能够开发一种针对广泛的细菌SNARE样蛋白的通用策略。设计能够破坏细菌SNARE样结构域的新细菌治疗剂应该可以逆转融合的阻断，并允许细菌被吞噬体清除。公共卫生相关性：该研究项目旨在确定细胞内细菌是否利用SNARE样蛋白来操纵宿主囊泡运输途径。结果将有助于更好地了解如何寄生虫含有空泡绕过溶酶体降解，并将阐明寄生虫细胞内生存的机制。此外，所提出的研究对于开发新的治疗方法以诱导宿主细胞清除细胞内细菌具有实际应用。

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.