共查询到19条相似文献，搜索用时 46 毫秒
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细菌Ⅴ型分泌系统研究进展 总被引：1，自引：0，他引：1
目前已知革兰阴性(G-)细菌的分泌系统至少有5种类型,即Ⅰ～Ⅴ型。其中Ⅴ型分泌系统为G-菌外膜通道转运蛋白系统中最大的一个家族,该系统又称自主转运蛋白系统,它首先通过Sec依赖的分泌通路跨内膜转运,到达外周质间隙后,又通过自身的C端在外膜上形成一个β折叠桶实现跨外膜转运。Ⅴ型分泌系统的分泌装置最为单一,且该系统分泌的蛋白在跨外膜转运过程中似乎不需要能量和辅助因子(蛋白)的参与。随着对运用Ⅴ型分泌系统在G-菌表面展示异源性多肽/蛋白质的深入研究,该系统在生物技术领域已展示出巨大的应用前景。 相似文献
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摘要:青枯菌(Ralstonia solanacearum)可导致多种重要经济作物毁灭性枯萎(bacterial wilt,又称青枯病),是世界上分布最广、危害最严重的十大植物病原细菌之一。注射器状的三型分泌系统(Type III secretion system)是青枯菌的一个决定性致病因子,青枯菌利用T3SS向寄主细胞中注射大量效应蛋白(Type III effectors)来抑制寄主的免疫反应,从而引起寄主感病。本文围绕近年来有关青枯菌T3SS 遗传特性、表达调控、效应蛋白功能等方面最新进展进行综述,为全面了解青枯菌致病机理和植物细菌病害的防治提供新思路。 相似文献
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蛋白质分泌系统是细菌与外界交流的重要工具。革兰氏阴性细菌的Ⅵ型蛋白分泌系统(T6SS)可以转运分泌蛋白至细菌和真核细胞内,在菌间竞争中发挥重要作用,是细菌的一种重要的生存适应性武器。分泌蛋白主要包括起到运载作用的结构蛋白和有细胞毒性的效应蛋白这两类。本文主要从效应蛋白的视角讨论T6SS如何识别并转运效应蛋白的作用机理,回顾了以VgrG和PAAR为端部载体蛋白的转运途径、依赖端部运输的效应蛋白、T6SS伴侣蛋白等重要发现的背景和过程,并综述了T6SS分泌途径的新进展。 相似文献
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细菌Ⅶ型分泌系统的研究进展 总被引：1，自引：0，他引：1
细菌分泌系统参与细菌物质转运,是细菌蛋白或DNA胞外分泌的重要途径,与细菌的生长和致病性密切相关。迄今为止,已发现了Ⅰ～Ⅶ型分泌系统。Ⅰ～Ⅵ型分泌系统存在于革兰阴性菌中,其中Ⅳ型也存在于革兰阳性菌中;Ⅶ型则存在于革兰阳性菌中。Ⅶ型分泌系统是近年来发现的一种特殊分泌系统,能介导病原微生物毒力蛋白分泌,与宿主相互作用,并参与细菌体内锌铁平衡等,在革兰阳性菌的生长代谢及致病过程中发挥重要作用。本文综述细菌Ⅶ型分泌系统的类型、功能及表达调控,以增进对这一新型细菌蛋白分泌机制的认识。 相似文献
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细菌通过其分泌系统将特定的效应蛋白输送到外界环境或进入靶细胞中,从而在细菌和宿主、细菌和微生物群落的相互作用中占据适应性优势。Ⅵ型分泌系统（The type VI secretion system,T6SS）是革兰氏阴性菌中广泛存在的大分子分泌装置,其结构和功能类似于可收缩的噬菌体尾针样,通过细胞间直接接触将细菌各种酶或毒素效应蛋白转运到原核和真核生物中,从而介导细菌间竞争以及对宿主的致病过程。有些效应蛋白还可通过非接触依赖的方式进入胞外环境来帮助细菌获取稀缺金属离子,并且它们对应激条件下细胞内金属稳态的维持至关重要。这篇综述总结了Ⅵ型分泌系统的结构、组装及其分泌的效应蛋白,并重点阐述了Ⅵ型分泌系统在多种金属离子转运机制中作用的研究进展,有助于理解T6SS在细菌间相互作用和细菌感染过程中发挥的重要作用。 相似文献
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嗜肺军团菌是引起军团菌肺炎以及庞蒂亚克热的革兰氏阴性胞内病原细菌,嗜肺军团菌侵染宿主的主要特点是可以通过其IVB型毒力分泌系统,向宿主细胞内分泌超过150种的底物效应蛋白。通过这些效应蛋白的作用,嗜肺军团菌能够调整宿主细胞的胞内运输途径,改变内外环境来伪装自己的吞噬泡,干扰宿主的细胞周期,抑制宿主细胞的凋亡,从而有效逃避宿主细胞的防御功能,创造出理想的胞内增殖环境。最后,效应蛋白还可以帮助军团菌从宿主细胞中逃逸。目前,嗜肺军团菌已经成为"病原菌-宿主相互作用"的重要研究模型,其毒力分泌系统及其底物效应蛋白的功能也成为细胞微生物学的研究热点。对嗜肺军团菌分泌系统及效应蛋白的研究不仅能够帮助阐明病原细菌的致病机理,还有助于推动对宿主免疫机制的更深层次的研究。文章主要针对嗜肺军团菌的毒力分泌系统,尤其是IVB型分泌系统的结构和功能,以及底物效应蛋白的研究进展进行了综述,向读者展示出一个小小的细菌所拥有的那令人惊叹的、如此狡猾的生存策略和它精致的杀伤武器。 相似文献
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细菌的肽转运蛋白包括3种,寡肽转运蛋白(Oligopeptide permease,Opp)、二肽转运蛋白(Dipeptide permease,Dpp)和二/三肽转运蛋白(Di-and tripeptide permease,Dtp)。Opp和Dpp属于ABC型超家族(ATP-binding cassette superfamily)转运蛋白,利用ATP水解产生的能量实现底物转运。对Opp和Dpp研究最多的是胞外肽结合蛋白OppA和DppA,它们起着最初识别与结合底物的重要作用。Dtp属于主要协助转运蛋白超家族(Major facilitator superfamily,MFS),与质子进行底物共转运。细菌肽转运蛋白的晶体结构解析结合大量的生化数据分析,使得人们对其转运机制有了深入的了解。本文对这三种肽转运蛋白的研究进展分别进行综述。 相似文献
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The direct transport of virulence proteins from bacterium to host has emerged as a common strategy employed by Gram-negative pathogens to establish infections. Specialized secretion systems function to facilitate this process. The delivery of 'effector' proteins by these secretion systems is currently confined to two functionally similar but mechanistically distinct pathways, termed type III and type IV secretion. The type III secretion pathway is ancestrally related to the multiprotein complexes that assemble flagella, whereas the type IV mechanism probably emerged from the protein complexes that support conjugal transfer of DNA. Although both pathways serve to transport proteins from the bacterium to host, the recognition of the effector protein substrates and the secretion information contained in these proteins appear highly distinct. Here, we review the mechanisms involved in the selection of substrates by each of these transport systems and secretion signal information required for substrate transport. 相似文献
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The Gram-negative pathogen Salmonella enterica can survive and replicate within a variety of mammalian cells. Regardless of the cell type, internalized bacteria survive and replicate within the Salmonella -containing vacuole, the biogenesis of which is dependent on bacterially encoded virulence factors. In particular, Type III secretion systems translocate bacterial effector proteins into the eukaryotic cell where they can specifically interact with a variety of targets. Salmonella has two distinct Type III secretion systems that are believed to have completely different functions. The SPI2 system is induced intracellularly and is required for intracellular survival in macrophages; it plays no role in invasion but is categorized as being required for Salmonella -containing vacuole biogenesis. In contrast, the SPI1 Type III secretion system is induced extracellularly and is essential for invasion of nonphagocytic cells. Its role in post-invasion processes has not been well studied. Recent studies indicate that Salmonella -containing vacuole biogenesis may be more dependent on SPI1 than previously believed. Other non-SPI2 virulence factors and the host cell itself may play critical roles in determining the intracellular environment of this facultative intracellular pathogen. In this review we discuss the recent advances in determining the mechanisms by which Salmonella regulate Salmonella -containing vacuole biogenesis and the implications of these findings. 相似文献
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Steele-Mortimer O 《Traffic (Copenhagen, Denmark)》2011,12(2):162-169
A variety of bacterial intracellular pathogens target the host cell ubiquitin system during invasion, a process that involves transient but fundamental changes in the actin cytoskeleton and plasma membrane. These changes are induced by bacterial proteins, which can be surface associated, secreted or injected directly into the host cell. Here, the invasion strategies of two extensively studied intracellular bacteria, Salmonella enterica serovar Typhimurium and Listeria monocytogenes, are used to illustrate some of the diverse ways by which bacterial pathogens intersect the host cell ubiquitin pathway. 相似文献
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病原菌效应蛋白破坏宿主细胞的正常信号转导是病原菌和宿主相互作用的重要体现.效应蛋白往往具有独特的生化活性,针对宿主细胞内与抗细菌感染相关的重要通路进行阻断.近年来,在病原菌效应蛋白作用机制的研究中,人们发现了几种由效应蛋白介导的全新的蛋白质翻译后修饰.OspF(outer Shigella protein F)效应蛋白家族具有磷酸化苏氨酸裂合酶活性,通过\"消去\"修饰和失活宿主MAPK激酶.NleE(non-LEE encoded effector E)效应蛋白则通过半胱氨酸甲基化修饰来抑制感染诱导NF-κB炎症通路的激活.NleB(non-LEEencoded effectorB)蛋白抑制宿主的死亡信号通路,则依赖于其N-乙酰葡萄糖胺转移酶活性介导的对死亡结构域蛋白的精氨酸糖基化修饰.而VopS(Vibrio outer protein S)和IbpA(Immunoglobulin-binding protein A)等含有Fic结构域的蛋白,则可以将AMP基团转移到Rho家族小G蛋白的保守苏氨酸或酪氨酸上,导致小G蛋白的失活和肌动蛋白细胞骨架的紊乱,从而引起细胞毒性.以上效应蛋白作用机制及生化活性的阐明,有助于全方位了解病原菌的致病毒力机制,也开辟了蛋白质翻译后修饰介导病原-宿主相互作用研究的新方向,同时对真核生物的信号转导研究也具有重要指导意义. 相似文献
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副溶血弧菌Ⅲ型分泌系统（T3SS）效应蛋白及其对宿主细胞的操控 总被引：1，自引：0，他引：1
副溶血弧菌是典型的食源性病原菌,也是全球范围内引起肠胃炎的主要病原菌。针筒状的Ⅲ型分泌系统(T3SS)为该菌主要的毒力因子,细菌感染时可将其效应蛋白直接注射至宿主细胞中,通过效应蛋白操纵宿主细胞,介导毒力的发挥。多数临床分离的副溶血弧菌含有2套T3SSs,其中T3SS1分泌的效应蛋白主要通过诱导细胞自噬、变圆和裂解等过程来发挥其细胞毒性,而T3SS2分泌的效应蛋白则主要通过破坏细胞骨架和操控细胞信号传导来发挥肠毒性。本文主要对副溶血弧菌T3SSs的组成和目前已发现的效应蛋白及其对宿主细胞的操控进行介绍。该研究不仅对深入了解该菌的致病机制有重要意义,而且也为宿主细胞信号转导机制研究提供新视角。 相似文献
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Samnyu Jee In-Jeong Kang Gyeryeong Bak Sera Kang Jeongtae Lee Sunggi Heu Ingyu Hwang 《The Plant Pathology Journal》2022,38(1):12
In this study, we conducted whole-genome sequencing with six species of Pectobacterium composed of seven strains, JR1.1, BP201601.1, JK2.1, HNP201719, MYP201603, PZ1, and HC, for the analysis of pathogenic factors associated with the genome of Pectobacterium. The genome sizes ranged from 4,724,337 bp to 5,208,618 bp, with the GC content ranging from 50.4% to 52.3%. The average nucleotide identity was 98% among the two Pectobacterium species and ranged from 88% to 96% among the remaining six species. A similar distribution was observed in the carbohydrate-active enzymes (CAZymes) class and extracellular plant cell wall degrading enzymes (PCWDEs). HC showed the highest number of enzymes in CAZymes and the lowest number in the extracellular PCWDEs. Six strains showed four subsets, and HC demonstrated three subsets, except hasDEF, in type I secretion system, while the type II secretion system of the seven strains was conserved. Components of human pathogens, such as Salmonella pathogenicity island 1 type type III secretion system (T3SS) and effectors, were identified in PZ1; T3SSa was not identified in HC. Two putative effectors, including hrpK, were identified in seven strains along with dspEF. We also identified 13 structural genes, six regulator genes, and five accessory genes in the type VI secretion system (T6SS) gene cluster of six Pectobacterium species, along with the loss of T6SS in PZ1. HC had two subsets, and JK2.1 had three subsets of T6SS. With the GxSxG motif, the phospholipase A gene did locate among tssID and duf4123 genes in the T6SSa cluster of all strains. Important domains were identified in the vgrG/paar islands, including duf4123, duf2235, vrr-nuc, and duf3396. 相似文献
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嗜肺军团菌(Legionella pneumophila,L. pneumophila)是研究病原菌-宿主相互作用的重要模式菌株之一,其独特的分泌系统及底物效应蛋白的结构与功能是病原微生物领域的研究热点。II型分泌系统(type II secretion system,T2SS)对促进细菌在环境和人类宿主中的生存至关重要。嗜肺军团菌Legionella secretion pathway (Lsp)系统是革兰氏阴性病原菌中一个典型的T2SS。本文综述了L. pneumophila的T2SS及其底物效应蛋白的研究进展,重点介绍其结构与功能,为深入了解革兰氏阴性病原菌的T2SS功能和作用机制提供参考。 相似文献
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Jun Kurushima Takeshi Nagai Kanna Nagamatsu Akio Abe 《Microbiology and immunology》2010,54(7):371-379
EHEC is a bacterial pathogen causing diarrhea and hemorrhagic colitis in humans. To exert virulence, EHEC exploits a subset of effectors that are translocated into host cells via the type III secretion system. EspJ, which was recently identified as a type III secreted effector, is conserved in related pathogens such as EPEC and Citrobacter rodentium. However, the exact function of EspJ remains unclear. In the present study, we found that EspJ was unstable in host cells, which might be attributable to the N‐terminal part beginning from amino acid number 59. Using stable forms of EspJ derivatives, we demonstrated for the first time that EspJ has the ability to translocate into mitochondria via an atypical mitochondrial targeting signal at the N terminus (1–36 a.a.) of EspJ. It has been reported that a mitochondrial targeting effector, EspF, disrupts the mitochondrial membrane potential, resulting in an induction of host cell death. To further investigate EspJ function in mitochondria, HeLa cells were infected with wild‐type EPEC, an isogenic EspJ‐mutant or an EspJ‐overexpressing strain. The result of LDH release assay using an EspJ‐mutant showed that the EspJ effector appears not to be involved in cytotoxicity. 相似文献