scholarly journals Type VI secretion system sheaths as nanoparticles for antigen display

2016 ◽  
Vol 113 (11) ◽  
pp. 3042-3047 ◽  
Author(s):  
Elena Del Tordello ◽  
Olga Danilchanka ◽  
Andrew J. McCluskey ◽  
John J. Mekalanos
Keyword(s):  
Protein A ◽  
Secretion System ◽  
Factor H ◽  
Soluble Antigen ◽  
Tubular Structures ◽  
Type Vi Secretion System ◽  
Interacting Protein ◽  
Serum Bactericidal Assay ◽  
Heterologous Antigens ◽  
Bacterial Type

The bacterial type 6 secretion system (T6SS) is a dynamic apparatus that translocates proteins between cells by a mechanism analogous to phage tail contraction. T6SS sheaths are cytoplasmic tubular structures composed of stable VipA-VipB (named for ClpV-interacting protein A and B) heterodimers. Here, the structure of the VipA/B sheath was exploited to generate immunogenic multivalent particles for vaccine delivery. Sheaths composed of VipB and VipA fused to an antigen of interest were purified from Vibrio cholerae or Escherichia coli and used for immunization. Sheaths displaying heterologous antigens generated better immune responses against the antigen and different IgG subclasses compared with soluble antigen alone. Moreover, antigen-specific antibodies raised against sheaths presenting Neisseria meningitidis factor H binding protein (fHbp) antigen were functional in a serum bactericidal assay. Our results demonstrate that multivalent nanoparticles based on the T6SS sheath represent a versatile scaffold for vaccine applications.

scholarly journals VipA N-terminal linker and VipB-VipB interaction modulate the contraction of Type VI secretion system sheath

2017 ◽  
Author(s):  
Maximilian Brackmann ◽  
Jing Wang ◽  
Marek Basler
Keyword(s):  
Protein Translocation ◽  
Secretion System ◽  
Mass Spectrometry Analysis ◽  
Target Cells ◽  
Extended State ◽  
Type Vi Secretion System ◽  
Secretion Systems ◽  
Spectrometry Analysis ◽  
Type Vi Secretion ◽  
Bacterial Type

AbstractSecretion systems are essential for bacteria to survive and manipulate their environment. The bacterial Type VI Secretion System (T6SS) generates the force needed for protein translocation by the contraction of a long polymer called sheath, which is composed of interconnected VipA/VipB subunits forming a six-start helix. The mechanism of T6SS sheath contraction and the structure of its extended state are unknown. Here we show that elongating the N-terminal VipA linker or eliminating charge of a specific VipB residue abolished sheath contraction and delivery of effectors into target cells. The assembly of the non-contractile sheaths was dependent on the baseplate component TssE and mass-spectrometry analysis identified Hcp, VgrG and other components of the T6SS baseplate specifically associated with stable non-contractile sheaths. The ability to lock T6SS in the pre-firing state opens new possibilities for understanding its mode of action.

scholarly journals Characterization of the Pseudomonas aeruginosa T6SS PldB immunity proteins PA5086, PA5087 and PA5088 explains a novel stockpiling mechanism

2020 ◽  
Vol 76 (5) ◽  
pp. 222-227
Author(s):  
Haiying Wen ◽  
Zhi Geng ◽  
Zengqiang Gao ◽  
Zhun She ◽  
Yuhui Dong
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Structural Comparison ◽  
Interesting Phenomenon ◽  
Potential Surfaces ◽  
Type Vi Secretion ◽  
Host Infection ◽  
Bacterial Type

The bacterial type VI secretion system (T6SS) secretes many toxic effectors to gain advantage in interbacterial competition and for eukaryotic host infection. The cognate immunity proteins of these effectors protect bacteria from their own effectors. PldB is a T6SS trans-kingdom effector in Pseudomonas aeruginosa that can infect both prokaryotic and eukaryotic cells. Three proteins, PA5086, PA5087 and PA5088, are employed to suppress the toxicity of PldB-family proteins. The structures of PA5087 and PA5088 have previously been reported, but the identification of further distinctions between these immunity proteins is needed. Here, the crystal structure of PA5086 is reported at 1.90 Å resolution. A structural comparison of the three PldB immunity proteins showed vast divergences in their electrostatic potential surfaces. This interesting phenomenon provides an explanation of the stockpiling mechanism of T6SS immunity proteins.

scholarly journals A proposed chaperone of the bacterial type VI secretion system functions to constrain a self-identity protein

2017 ◽  
Author(s):  
Martha A. Zepeda-Rivera ◽  
Christina C. Saak ◽  
Karine A. Gibbs
Keyword(s):  
Secretion System ◽  
Infection Model ◽  
Type Vi Secretion System ◽  
Self Identity ◽  
Fitness Advantage ◽  
Mouse Infection Model ◽  
Type Vi Secretion ◽  
The Stability ◽  
Bacterial Type ◽  
Polymicrobial Infections

AbstractThe opportunistic bacterial uropathogenProteus mirabiliscan communicate identity through the export of the self-identity protein, IdsD, via the type VI secretion (T6S) system. Expression of theidsgenes provides a fitness advantage during polymicrobial infections in a mouse infection model. Here we provide an answer to the unresolved question of how the activity of a T6S substrate, such as IdsD, is regulated before export. We demonstrate that IdsD is found in clusters that form independently of the T6S machinery and activity. We show that the protein IdsC, which is a member of the proposed DUF4123 chaperone family, is essential for the stability of these clusters as well as the IdsD protein itself. And we provide evidence that amino acid disruptions in IdsC are sufficient to disrupt IdsD export but not IdsD localization into stable subcellular clusters, strongly supporting that IdsC functions in at least two different ways: IdsD stabilization and IdsD export. We propose that IdsC, and likely other DUF4123-containing proteins, function to regulate T6S substrates before export by both stabilizing the protein and mediating export at the T6S machinery.

scholarly journals In situ and high‐resolution cryo‐ EM structure of a bacterial type VI secretion system membrane complex

2019 ◽  
Vol 38 (10) ◽  
Author(s):  
Chiara Rapisarda ◽  
Yassine Cherrak ◽  
Romain Kooger ◽  
Victoria Schmidt ◽  
Riccardo Pellarin ◽  
...  
Keyword(s):  
High Resolution ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Membrane Complex ◽  
Type Vi Secretion ◽  
Bacterial Type

scholarly journals Biochemical analysis of TssK, a core component of the bacterial Type VI secretion system, reveals distinct oligomeric states of TssK and identifies a TssK–TssFG subcomplex

2014 ◽  
Vol 461 (2) ◽  
pp. 291-304 ◽  
Author(s):  
Grant English ◽  
Olwyn Byron ◽  
Francesca R. Cianfanelli ◽  
Alan R. Prescott ◽  
Sarah J. Coulthurst
Keyword(s):  
Biochemical Analysis ◽  
Secretion System ◽  
Type Vi Secretion System ◽  
Core Component ◽  
Essential Component ◽  
Type Vi Secretion ◽  
Core Components ◽  
Bacterial Type

Genetic and biochemical analysis of TssK, an essential component of the bacterial Type VI secretion system, revealed that it forms a new subcomplex with two other core components, TssF and TssG, and displays several oligomerization states in vitro.

scholarly journals Functional Exploration of the Bacterial Type VI Secretion System in Mutualism: Azorhizobium caulinodans ORS571–Sesbania rostrata as a Research Model

2018 ◽  
Vol 31 (8) ◽  
pp. 856-867 ◽  
Author(s):  
Hsiao-Han Lin ◽  
Hsin-Mei Huang ◽  
Manda Yu ◽  
Erh-Min Lai ◽  
Hsiao-Lin Chien ◽  
...  
Keyword(s):  
Culture Conditions ◽  
Secretion System ◽  
Sesbania Rostrata ◽  
Research Model ◽  
Azorhizobium Caulinodans ◽  
Wild Type ◽  
Type Vi Secretion System ◽  
Type Vi Secretion ◽  
Azorhizobium Caulinodans Ors571 ◽  
Bacterial Type

The bacterial type VI secretion system (T6SS) has been considered the armed force of bacteria because it can deliver toxin effectors to prokaryotic or eukaryotic cells for survival and fitness. Although many legume symbiotic rhizobacteria encode T6SS in their genome, the biological function of T6SS in these bacteria is still unclear. To elucidate this issue, we used Azorhizobium caulinodans ORS571 and its symbiotic host Sesbania rostrata as our research model. By using T6SS gene deletion mutants, we found that T6SS provides A. caulinodans with better symbiotic competitiveness when coinfected with a T6SS-lacking strain, as demonstrated by two independent T6SS-deficient mutants. Meanwhile, the symbiotic effectiveness was not affected by T6SS because the nodule phenotype, nodule size, and nodule nitrogen-fixation ability did not differ between the T6SS mutants and the wild type when infected alone. Our data also suggest that under several lab culture conditions tested, A. caulinodans showed no T6SS-dependent interbacterial competition activity. Therefore, instead of being an antihost or antibacterial weapon of the bacterium, the T6SS in A. caulinodans ORS571 seems to participate specifically in symbiosis by increasing its symbiotic competitiveness.

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