EcoSal Plus最新文献_第7页

Outer Membrane Protein Insertion by the β-barrel Assembly Machine. β桶组装机外膜蛋白插入。

EcoSal Plus Pub Date : 2019-03-01 DOI: 10.1128/ecosalplus.ESP-0035-2018

Dante P Ricci, Thomas J Silhavy

引用次数: 22

Therapeutic Approaches Targeting the Assembly and Function of Chaperone-Usher Pili. 针对伴侣纤毛虫组装和功能的治疗方法。

EcoSal Plus Pub Date : 2019-03-01 DOI: 10.1128/ecosalplus.ESP-0033-2018

John J Psonis, David G Thanassi

{"title":"Therapeutic Approaches Targeting the Assembly and Function of Chaperone-Usher Pili.","authors":"John J Psonis, David G Thanassi","doi":"10.1128/ecosalplus.ESP-0033-2018","DOIUrl":"10.1128/ecosalplus.ESP-0033-2018","url":null,"abstract":"The chaperone-usher (CU) pathway is a conserved secretion system dedicated to the assembly of a superfamily of virulence-associated surface structures by a wide range of Gram-negative bacteria. Pilus biogenesis by the CU pathway requires two specialized assembly components: a dedicated periplasmic chaperone and an integral outer membrane assembly and secretion platform termed the usher. The CU pathway assembles a variety of surface fibers, ranging from thin, flexible filaments to rigid, rod-like organelles. Pili typically act as adhesins and function as virulence factors that mediate contact with host cells and colonization of host tissues. Pilus-mediated adhesion is critical for early stages of infection, allowing bacteria to establish a foothold within the host. Pili are also involved in modulation of host cell signaling pathways, bacterial invasion into host cells, and biofilm formation. Pili are critical for initiating and sustaining infection and thus represent attractive targets for the development of antivirulence therapeutics. Such therapeutics offer a promising alternative to broad-spectrum antibiotics and provide a means to combat antibiotic resistance and treat infection while preserving the beneficial microbiota. A number of strategies have been taken to develop antipilus therapeutics, including vaccines against pilus proteins, competitive inhibitors of pilus-mediated adhesion, and small molecules that disrupt pilus biogenesis. Here we provide an overview of the function and assembly of CU pili and describe current efforts aimed at interfering with these critical virulence structures.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422168/pdf/nihms-1006342.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37233432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Curli Biogenesis: Bacterial Amyloid Assembly by the Type VIII Secretion Pathway. Curli Biogenesis:细菌淀粉样蛋白通过VIII型分泌途径组装。

EcoSal Plus Pub Date : 2019-03-01 DOI: 10.1128/ecosalplus.ESP-0037-2018

Sujeet Bhoite, Nani van Gerven, Matthew R Chapman, Han Remaut

{"title":"Curli Biogenesis: Bacterial Amyloid Assembly by the Type VIII Secretion Pathway.","authors":"Sujeet Bhoite, Nani van Gerven, Matthew R Chapman, Han Remaut","doi":"10.1128/ecosalplus.ESP-0037-2018","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0037-2018","url":null,"abstract":"In 1989, Normark and coworkers reported on fibrous surface structures called curli on strains of Escherichia coli that were suspected of causing bovine mastitis. Subsequent work by many groups has revealed an elegant and highly regulated curli biogenesis pathway also referred to as the type VIII secretion system. Curli biogenesis is governed by two divergently transcribed operons, csgBAC and csgDEFG. The csgBAC operon encodes the structural subunits of curli, CsgA and CsgB, along with a chaperone-like protein, CsgC. The csgDEFG operon encodes the accessory proteins required for efficient transcription, secretion, and assembly of the curli fiber. CsgA and CsgB are secreted as largely unstructured proteins and transition to β-rich structures that aggregate into regular fibers at the cell surface. Since both of these proteins have been shown to be amyloidogenic in nature, the correct spatiotemporal synthesis of the curli fiber is of paramount importance for proper functioning and viability. Gram-negative bacteria have evolved an elegant machinery for the safe handling, secretion, and extracellular assembly of these amyloidogenic proteins.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0037-2018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37074273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 36

The Injectisome, a Complex Nanomachine for Protein Injection into Mammalian Cells. 注射体--一种用于向哺乳动物细胞注射蛋白质的复杂纳米机器。

EcoSal Plus Pub Date : 2019-03-01 DOI: 10.1128/ecosalplus.ESP-0039-2018

Maria Lara-Tejero, Jorge E Galán

{"title":"The Injectisome, a Complex Nanomachine for Protein Injection into Mammalian Cells.","authors":"Maria Lara-Tejero, Jorge E Galán","doi":"10.1128/ecosalplus.ESP-0039-2018","DOIUrl":"10.1128/ecosalplus.ESP-0039-2018","url":null,"abstract":"Type III protein secretion systems (T3SSs), or injectisomes, are multiprotein nanomachines present in many Gram-negative bacteria that have a sustained long-standing close relationship with a eukaryotic host. These secretion systems have evolved to modulate host cellular functions through the activity of the effector proteins they deliver. To reach their destination, T3SS effectors must cross the multibarrier bacterial envelope and the eukaryotic cell membrane. Passage through the bacterial envelope is mediated by the needle complex, a central component of T3SSs that expands both the inner and outer membranes of Gram-negative bacteria. A set of T3SS secreted proteins, known as translocators, form a channel in the eukaryotic plasma membrane through which the effector proteins are delivered to reach the host cell cytosol. While the effector proteins are tailored to the specific lifestyle of the bacterium that encodes them, the injectisome is conserved among the different T3SSs. The central role of T3SSs in pathogenesis and their high degree of conservation make them a desirable target for the development of antimicrobial therapies against several important bacterial pathogens.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6450406/pdf/nihms-1010190.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37115204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Lipoproteins and Their Trafficking to the Outer Membrane. 脂蛋白及其向外膜的运输

EcoSal Plus Pub Date : 2019-03-01 DOI: 10.1128/ecosalplus.ESP-0038-2018

Marcin Grabowicz

{"title":"Lipoproteins and Their Trafficking to the Outer Membrane.","authors":"Marcin Grabowicz","doi":"10.1128/ecosalplus.ESP-0038-2018","DOIUrl":"10.1128/ecosalplus.ESP-0038-2018","url":null,"abstract":"Lipoproteins are produced by both Gram-positive and Gram-negative bacteria. Once secreted, lipoproteins are quickly acylated, anchoring them into the plasma membrane. Recent work has shown that Gram-positive bacteria are able to generate considerable diversity in the acylation of their lipoproteins, though the mechanisms involved are only just beginning to emerge. In Gram-negative organisms, most lipoproteins are subsequently trafficked to the outer membrane (OM). Lipoprotein trafficking is an essential pathway in these bacteria. At least one OM lipoprotein component is required by each of the essential machines that assemble the OM (such as the Bam and Lpt machines) and build the peptidoglycan cell wall (Lpo-penicillin-binding protein complexes). The Lol pathway has been the paradigm for OM lipoprotein trafficking: a complex of LolCDE extracts lipoproteins from the plasma membrane, LolA shuttles them through the periplasmic space, and LolB anchors them into the OM. The peptide signals responsible for OM-targeting via LolCDE have long been known for Escherichia coli. Remarkably, production of novel lipoprotein acyl forms in E. coli has reinforced the idea that lipid signals also contribute to OM targeting via LolCDE. Moreover, recent work has shown that lipoprotein trafficking can occur in E. coli without either LolA or LolB. Therefore, current evidence suggests that at least one additional, LolAB-independent route for OM lipoprotein trafficking exists. This chapter reviews the posttranslocation modifications of all lipoproteins, with a focus on the trafficking of lipoproteins to the OM of Gram-negative bacteria.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11573296/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37256757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Disulfide Bond Formation in the Periplasm of Escherichia coli. 大肠杆菌胞浆中二硫键的形成。

EcoSal Plus Pub Date : 2019-02-01 DOI: 10.1128/ecosalplus.ESP-0012-2018

Bruno Manta, Dana Boyd, Mehmet Berkmen

引用次数: 0

Mechanisms of Type I-E and I-F CRISPR-Cas Systems in Enterobacteriaceae. 肠杆菌科 I-E 型和 I-F 型 CRISPR-Cas 系统的机制。

EcoSal Plus Pub Date : 2019-02-01 DOI: 10.1128/ecosalplus.ESP-0008-2018

Chaoyou Xue, Dipali G Sashital

{"title":"Mechanisms of Type I-E and I-F CRISPR-Cas Systems in Enterobacteriaceae.","authors":"Chaoyou Xue, Dipali G Sashital","doi":"10.1128/ecosalplus.ESP-0008-2018","DOIUrl":"10.1128/ecosalplus.ESP-0008-2018","url":null,"abstract":"CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against invasion by bacteriophages and other mobile genetic elements. Short fragments of invader DNA are stored as immunological memories within CRISPR (clustered regularly interspaced short palindromic repeat) arrays in the host chromosome. These arrays provide a template for RNA molecules that can guide CRISPR-associated (Cas) proteins to specifically neutralize viruses upon subsequent infection. Over the past 10 years, our understanding of CRISPR-Cas systems has benefited greatly from a number of model organisms. In particular, the study of several members of the Gram-negative Enterobacteriaceae family, especially Escherichia coli and Pectobacterium atrosepticum, have provided significant insights into the mechanisms of CRISPR-Cas immunity. In this review, we provide an overview of CRISPR-Cas systems present in members of the Enterobacteriaceae. We also detail the current mechanistic understanding of the type I-E and type I-F CRISPR-Cas systems that are commonly found in enterobacteria. Finally, we discuss how phages can escape or inactivate CRISPR-Cas systems and the measures bacteria can enact to counter these types of events.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6368399/pdf/nihms-1004596.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36980852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Architecture, Function, and Substrates of the Type II Secretion System. II型分泌系统的结构、功能和底物。

EcoSal Plus Pub Date : 2019-02-01 DOI: 10.1128/ecosalplus.ESP-0034-2018

Konstantin V Korotkov, Maria Sandkvist

{"title":"Architecture, Function, and Substrates of the Type II Secretion System.","authors":"Konstantin V Korotkov, Maria Sandkvist","doi":"10.1128/ecosalplus.ESP-0034-2018","DOIUrl":"https://doi.org/10.1128/ecosalplus.ESP-0034-2018","url":null,"abstract":"The type II secretion system (T2SS) delivers toxins and a range of hydrolytic enzymes, including proteases, lipases, and carbohydrate-active enzymes, to the cell surface or extracellular space of Gram-negative bacteria. Its contribution to survival of both extracellular and intracellular pathogens as well as environmental species of proteobacteria is evident. This dynamic, multicomponent machinery spans the entire cell envelope and consists of a cytoplasmic ATPase, several inner membrane proteins, a periplasmic pseudopilus, and a secretin pore embedded in the outer membrane. Despite the trans-envelope configuration of the T2S nanomachine, proteins to be secreted engage with the system first once they enter the periplasmic compartment via the Sec or TAT export system. Thus, the T2SS is specifically dedicated to their outer membrane translocation. The many sequence and structural similarities between the T2SS and type IV pili suggest a common origin and argue for a pilus-mediated mechanism of secretion. This minireview describes the structures, functions, and interactions of the individual T2SS components and the general architecture of the assembled T2SS machinery and briefly summarizes the transport and function of a growing list of T2SS exoproteins. Recent advances in cryo-electron microscopy, which have led to an increased understanding of the structure-function relationship of the secretin channel and the pseudopilus, are emphasized.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1128/ecosalplus.ESP-0034-2018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36562024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 43

Type V Secretion in Gram-Negative Bacteria. 革兰氏阴性细菌的 V 型分泌。

EcoSal Plus Pub Date : 2019-02-01 DOI: 10.1128/ecosalplus.ESP-0031-2018

Harris D Bernstein

{"title":"Type V Secretion in Gram-Negative Bacteria.","authors":"Harris D Bernstein","doi":"10.1128/ecosalplus.ESP-0031-2018","DOIUrl":"10.1128/ecosalplus.ESP-0031-2018","url":null,"abstract":"Type V, or \"autotransporter,\" secretion is a term used to refer to several simple protein export pathways that are found in a wide range of Gram-negative bacteria. Autotransporters are generally single polypeptides that consist of an extracellular (\"passenger\") domain and a β barrel domain that anchors the protein to the outer membrane (OM). Although it was originally proposed that the passenger domain is secreted through a channel formed solely by the covalently linked β barrel domain, experiments performed primarily on the type Va, or \"classical,\" autotransporter pathway have challenged this hypothesis. Several lines of evidence strongly suggest that both the secretion of the passenger domain and the membrane integration of the β barrel domain are catalyzed by the barrel assembly machinery (Bam) complex, a conserved hetero-oligomer that plays an essential role in the assembly of most integral OM proteins. The secretion reaction appears to be driven at least in part by the folding of the passenger domain in the extracellular space. Although many aspects of autotransporter biogenesis remain to be elucidated, it will be especially interesting to determine whether the different classes of proteins that fall under the type V rubric-most of which have not been examined in detail-are assembled by the same basic mechanism as classical autotransporters.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404772/pdf/nihms-1002886.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"37189300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Promises and Challenges of the Type Three Secretion System Injectisome as an Antivirulence Target. 将第三类分泌系统注射体作为抗病毒目标的前景与挑战

EcoSal Plus Pub Date : 2019-02-01 DOI: 10.1128/ecosalplus.ESP-0032-2018

Alyssa C Fasciano, Lamyaa Shaban, Joan Mecsas

{"title":"Promises and Challenges of the Type Three Secretion System Injectisome as an Antivirulence Target.","authors":"Alyssa C Fasciano, Lamyaa Shaban, Joan Mecsas","doi":"10.1128/ecosalplus.ESP-0032-2018","DOIUrl":"10.1128/ecosalplus.ESP-0032-2018","url":null,"abstract":"Antibiotic resistance is a major public health threat that has stimulated the scientific community to search for nontraditional therapeutic targets. Because virulence, but not the growth, of many Gram-negative bacterial pathogens depends on the multicomponent type three secretion system injectisome (T3SSi), the T3SSi has been an attractive target for identifying small molecules, peptides, and monoclonal antibodies that inhibit its function to render the pathogen avirulent. While many small-molecule lead compounds have been identified in whole-cell-based high-throughput screens (HTSs), only a few protein targets of these compounds are known; such knowledge is an important step to developing more potent and specific inhibitors. Evaluation of the efficacy of compounds in animal studies is ongoing. Some efforts involving the development of antibodies and vaccines that target the T3SSi are further along and include an antibody that is currently in phase II clinical trials. Continued research into these antivirulence therapies, used alone or in combination with traditional antibiotics, requires combined efforts from both pharmaceutical companies and academic labs.","PeriodicalId":11500,"journal":{"name":"EcoSal Plus","volume":"8 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367940/pdf/nihms-1002889.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36966819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0