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https://www.readbyqxmd.com/read/28804481/the-type-vi-secretion-system-a-dynamic-system-for-bacterial-communication
#1
REVIEW
Mathias Gallique, Mathilde Bouteiller, Annabelle Merieau
Numerous studies in Gram-negative bacteria have focused on the Type VI Secretion Systems (T6SSs), Quorum Sensing (QS), and social behavior, such as in biofilms. These interconnected mechanisms are important for bacterial survival; T6SSs allow bacteria to battle other cells, QS is devoted to the perception of bacterial cell density, and biofilm formation is essentially controlled by QS. Here, we review data concerning T6SS dynamics and T6SS-QS cross-talk that suggest the existence of inter-bacterial communication via T6SSs...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28777089/crystal-structure-of-the-putative-cytoplasmic-protein-stm0279-hcp2-from-salmonella-typhimurium
#2
Qing Peng Lin, Zeng Qiang Gao, Zhi Geng, Heng Zhang, Yu Hui Dong
STM0279 is a putative cytoplasmic protein from Salmonella typhimurium and was recently renamed haemolysin co-regulated protein 2 (Hcp2), with the neighbouring STM0276 being Hcp1. Both of them are encoded by the type VI secretion system (T6SS) of the Salmonella pathogenicity island 6 (SPI-6) locus and have high sequence identity. The Hcp proteins may function as a vital component of the T6SS nanotube and as a transporter and chaperone of diverse effectors from the bacterial T6SS. In this study, the crystal structure and the oligomeric state in solution of Hcp2 from S...
August 1, 2017: Acta Crystallographica. Section F, Structural Biology Communications
https://www.readbyqxmd.com/read/28760929/entry-intracellular-survival-and-multinucleated-giant-cell-forming-activity-of-burkholderia-pseudomallei-in-human-primary-phagocytic-and-non-phagocytic-cells
#3
Liam Whiteley, Teresa Meffert, Maria Haug, Christopher Weidenmaier, Verena Hopf, Katharina Bitschar, Birgit Schittek, Christian Kohler, Ivo Steinmetz, T Eoin West, Sandra Schwarz
The human pathogen Burkholderia pseudomallei and the related species Burkholderia thailandensis are facultative intracellular bacteria characterized by the ability to escape into the cytosol of the host cell and to stimulate the formation of multinucleated giant cells (MNGCs). MNGC formation is induced via an unknown mechanism by the bacterial type VI secretion system 5 (T6SS-5), which is an essential virulence factor in both species. Despite the vital role of the intracellular life cycle in the pathogenesis of the bacteria, the range of host cell types permissive for initiation and completion of the intracellular cycle is poorly defined...
July 31, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/28758353/structural-and-saxs-analysis-of-tle5-tli5-complex-reveals-a-novel-inhibition-mechanism-of-h2-t6ss-in-pseudomonas-aeruginosa
#4
Xiao-Yun Yang, Zong-Qiang Li, Zeng-Qiang Gao, Wen-Jia Wang, Zhi Geng, Jian-Hua Xu, Zhun She, Yu-Hui Dong
Widely spread in gram-negative bacteria, the type VI secretion system (T6SS) secretes many effector-immunity protein pairs to help the bacteria compete against other prokaryotic rivals, and infect their eukaryotic hosts. Tle5 and Tle5B are two phospholipase effector protein secreted by T6SS of Pseudomonas aeruginosa. They can facilitate the bacterial internalization process into human epithelial cells by interacting with Akt protein of the PI3K-Akt signal pathway. Tli5 and PA5086-5088 are cognate immunity proteins of Tle5 and Tle5B, respectively...
July 30, 2017: Protein Science: a Publication of the Protein Society
https://www.readbyqxmd.com/read/28746878/the-type-vi-secretion-system-engages-a-redox-regulated-dual-functional-heme-transporter-for-zinc-acquisition
#5
Meiru Si, Yao Wang, Bing Zhang, Chao Zhao, Yiwen Kang, Haonan Bai, Dawei Wei, Lingfang Zhu, Lei Zhang, Tao G Dong, Xihui Shen
The type VI secretion system was recently reported to be involved in zinc acquisition, but the underlying mechanism remains unclear. Here, we report that Burkholderia thailandensis T6SS4 is involved in zinc acquisition via secretion of a zinc-scavenging protein, TseZ, that interacts with the outer membrane heme transporter HmuR. We find that HmuR is a redox-regulated dual-functional transporter that transports heme iron under normal conditions but zinc upon sensing extracellular oxidative stress, triggered by formation of an intramolecular disulfide bond...
July 25, 2017: Cell Reports
https://www.readbyqxmd.com/read/28743812/horizontal-gene-transfer-of-functional-type-vi-killing-genes-by-natural-transformation
#6
Jacob Thomas, Samit S Watve, William C Ratcliff, Brian K Hammer
Horizontal gene transfer (HGT) can have profound effects on bacterial evolution by allowing individuals to rapidly acquire adaptive traits that shape their strategies for competition. One strategy for intermicrobial antagonism often used by Proteobacteria is the genetically encoded contact-dependent type VI secretion system (T6SS), a weapon used to kill heteroclonal neighbors by direct injection of toxic effectors. Here, we experimentally demonstrate that Vibrio cholerae can acquire new T6SS effector genes via horizontal transfer and utilize them to kill neighboring cells...
July 25, 2017: MBio
https://www.readbyqxmd.com/read/28715501/diversity-and-distribution-of-nuclease-bacteriocins-in-bacterial-genomes-revealed-using-hidden-markov-models
#7
Connor Sharp, James Bray, Nicholas G Housden, Martin C J Maiden, Colin Kleanthous
Bacteria exploit an arsenal of antimicrobial peptides and proteins to compete with each other. Three main competition systems have been described: type six secretion systems (T6SS); contact dependent inhibition (CDI); and bacteriocins. Unlike T6SS and CDI systems, bacteriocins do not require contact between bacteria but are diffusible toxins released into the environment. Identified almost a century ago, our understanding of bacteriocin distribution and prevalence in bacterial populations remains poor. In the case of protein bacteriocins, this is because of high levels of sequence diversity and difficulties in distinguishing their killing domains from those of other competition systems...
July 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28703218/the-type-vi-secretion-system-sheath-assembles-at-the-end-distal-from-the-membrane-anchor
#8
Andrea Vettiger, Julius Winter, Lin Lin, Marek Basler
The bacterial Type VI secretion system (T6SS) delivers proteins into target cells using fast contraction of a long sheath anchored to the cell envelope and wrapped around an inner Hcp tube associated with the secreted proteins. Mechanisms of sheath assembly and length regulation are unclear. Here we study these processes using spheroplasts formed from ampicillin-treated Vibrio cholerae. We show that spheroplasts secrete Hcp and deliver T6SS substrates into neighbouring cells. Imaging of sheath dynamics shows that the sheath length correlates with the diameter of spheroplasts and may reach up to several micrometres...
July 13, 2017: Nature Communications
https://www.readbyqxmd.com/read/28673999/rsma-and-amrz-orchestrate-the-assembly-of-all-three-type-vi-secretion-systems-in-pseudomonas-aeruginosa
#9
Luke P Allsopp, Thomas E Wood, Sophie A Howard, Federica Maggiorelli, Laura M Nolan, Sarah Wettstadt, Alain Filloux
The type VI secretion system (T6SS) is a weapon of bacterial warfare and host cell subversion. The Gram-negative pathogen Pseudomonas aeruginosa has three T6SSs involved in colonization, competition, and full virulence. H1-T6SS is a molecular gun firing seven toxins, Tse1-Tse7, challenging survival of other bacteria and helping P. aeruginosa to prevail in specific niches. The H1-T6SS characterization was facilitated through studying a P. aeruginosa strain lacking the RetS sensor, which has a fully active H1-T6SS, in contrast to the parent...
July 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28667634/quantitative-determination-of-anti-bacterial-activity-during-bacterial-co-culture
#10
Juliana Alcoforado Diniz, Birte Hollmann, Sarah J Coulthurst
Anti-bacterial activity assays are an important tool in the assessment of the ability of one bacterium to kill or inhibit the growth of another, for example during the study of the Type VI secretion system (T6SS) and the anti-bacterial toxins it secretes. The method we describe here can detect the ability of a bacterial strain to kill or inhibit other bacterial cells in a contact-dependent manner when co-cultured on an agar surface. It is particularly useful since it enumerates the recovery of viable target cells and thus enables quantification of the anti-bacterial activity...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28667630/screening-for-secretion-of-the-type-vi-secretion-system-protein-hcp-by-enzyme-linked-immunosorbent-assay-and-colony-blot
#11
Brent S Weber, Pek Man Ly, Mario F Feldman
The bacterial type VI secretion system (T6SS) is a secretory apparatus encoded by many Gram-negative bacteria. The T6SS facilitates the secretion and injection of toxic effector proteins into host cells, providing a competitive advantage to bacteria encoding this machinery. The activity of the T6SS can be monitored by probing for the conserved tubule component Hcp, which is secreted to the supernatants by the T6SS. Detection of Hcp in culture supernatants is indicative of an active T6SS, but this secretion system is often tightly regulated or inactive under laboratory conditions and different bacterial strains display differing Hcp secretion phenotypes...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28667615/protein-protein-interactions-co-immunoprecipitation
#12
Jer-Sheng Lin, Erh-Min Lai
Proteins often do not function as single substances but rather as team players in a dynamic network. Growing evidence shows that protein-protein interactions are crucial in many biological processes in living cells. Genetic (such as yeast two-hybrid, Y2H) and biochemical (such as co-immunoprecipitation, co-IP) methods are the methods commonly used at the beginning of a study to identify the interacting proteins. Immunoprecipitation (IP), a method using a target protein-specific antibody in conjunction with Protein A/G affinity beads, is a powerful tool to identify molecules that interact with specific proteins...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28667612/protein-protein-interactions-yeast-two-hybrid-system
#13
Jer-Sheng Lin, Erh-Min Lai
The yeast two-hybrid system is a powerful and commonly used genetic tool to investigate interactions between artificial fusion proteins inside the nucleus of yeast. Here we describe how to use the Matchmaker GAL4-based yeast two-hybrid system to detect the interaction of the Agrobacterium type VI secretion system (T6SS) sheath components TssB and TssC41. The bait and prey gene are expressed as a fusion to the GAL4 DNA-binding domain (DNA-BD) and GAL4 activation domain (AD, prey/library fusion protein) respectively...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28664151/type-vi-secretion-effectors-methodologies-and-biology
#14
REVIEW
Yun-Wei Lien, Erh-Min Lai
The type VI secretion system (T6SS) is a nanomachine deployed by many Gram-negative bacteria as a weapon against eukaryotic hosts or prokaryotic competitors. It assembles into a bacteriophage tail-like structure that can transport effector proteins into the environment or target cells for competitive survival or pathogenesis. T6SS effectors have been identified by a variety of approaches, including knowledge/hypothesis-dependent and discovery-driven approaches. Here, we review and discuss the methods that have been used to identify T6SS effectors and the biological and biochemical functions of known effectors...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28650463/type-vi-secretion-tssk-baseplate-protein-exhibits-structural-similarity-with-phage-receptor-binding-proteins-and-evolved-to-bind-the-membrane-complex
#15
Van Son Nguyen, Laureen Logger, Silvia Spinelli, Pierre Legrand, Thi Thanh Huyen Pham, Thi Trang Nhung Trinh, Yassine Cherrak, Abdelrahim Zoued, Aline Desmyter, Eric Durand, Alain Roussel, Christine Kellenberger, Eric Cascales, Christian Cambillau
The type VI secretion system (T6SS) is a multiprotein machine widespread in Gram-negative bacteria that delivers toxins into both eukaryotic and prokaryotic cells. The mechanism of action of the T6SS is comparable to that of contractile myophages. The T6SS builds a tail-like structure made of an inner tube wrapped by a sheath, assembled under an extended conformation. Contraction of the sheath propels the inner tube towards the target cell. The T6SS tail is assembled on a platform-the baseplate-which is functionally similar to bacteriophage baseplates...
June 26, 2017: Nature Microbiology
https://www.readbyqxmd.com/read/28632016/the-bacteroides-fragilis-pathogenicity-island-links-virulence-and-strain-competition
#16
Benjamin W Casterline, Aaron L Hecht, Vivian M Choi, Juliane Bubeck Wardenburg
The mature microbiome is a stable ecosystem that resists perturbation despite constant host exposure to exogenous microbes. However, the microbial mechanisms determining microbiome development and composition are poorly understood. We recently demonstrated that a non-toxigenic B. fragilis (NTBF) strain restricts enteric colonization by an enterotoxigenic (ETBF) strain dependent on a type VI secretion system (T6SS). We show here that a second enterotoxigenic strain is competent to colonize, dependent on the Bacteroides fragilis pathogenicity island (BFPAI)...
February 23, 2017: Gut Microbes
https://www.readbyqxmd.com/read/28621333/francisella-requires-dynamic-type-vi-secretion-system-and-clpb-to-deliver-effectors-for-phagosomal-escape
#17
Maj Brodmann, Roland F Dreier, Petr Broz, Marek Basler
Francisella tularensis is an intracellular pathogen that causes the fatal zoonotic disease tularaemia. Critical for its pathogenesis is the ability of the phagocytosed bacteria to escape into the cell cytosol. For this, the bacteria use a non-canonical type VI secretion system (T6SS) encoded on the Francisella pathogenicity island (FPI). Here we show that in F. novicida T6SS assembly initiates at the bacterial poles both in vitro and within infected macrophages. T6SS dynamics and function depends on the general purpose ClpB unfoldase, which specifically colocalizes with contracted sheaths and is required for their disassembly...
June 16, 2017: Nature Communications
https://www.readbyqxmd.com/read/28618272/shigella-sonnei-encodes-a-functional-t6ss-used-for-interbacterial-competition-and-niche-occupancy
#18
Mark C Anderson, Pascale Vonaesch, Azadeh Saffarian, Benoit S Marteyn, Philippe J Sansonetti
Shigella is a leading cause of dysentery worldwide, with the majority of infections caused by two subgroups, S. flexneri and S. sonnei. Although S. flexneri has been highly prevalent in low-income countries, global development has brought an increase in S. sonnei at the expense of S. flexneri. However, the mechanisms behind this shift are not understood. Here we report that S. sonnei, but not S. flexneri, encodes a type VI secretion system (T6SS) that provides a competitive advantage in the gut. S. sonnei competes against E...
June 14, 2017: Cell Host & Microbe
https://www.readbyqxmd.com/read/28602424/using-force-to-punch-holes-mechanics-of-contractile-nanomachines
#19
REVIEW
Maximilian Brackmann, Sergey Nazarov, Jing Wang, Marek Basler
Using physical force to translocate macromolecules across a membrane has the advantage of being a universal solution independent of the properties of the target membrane. However, physically punching a stiff membrane is not a trivial task and three things are necessary for success: a sharp tip, a source of energy, and the ability to strongly bind to the target. In this review we describe the basic mechanism of membrane puncturing by contractile nanomachines with a focus on the T4 phage, R-type pyocin, and the bacterial Type VI secretion system (T6SS) based on recent studies of the structures and dynamics of their assembly...
June 8, 2017: Trends in Cell Biology
https://www.readbyqxmd.com/read/28594921/t6ss-the-bacterial-fight-club-in-the-host-gut
#20
Thibault G Sana, Kyler A Lugo, Denise M Monack
No abstract text is available yet for this article.
June 2017: PLoS Pathogens
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