scholarly journals Francisella IglG protein and the DUF4280 proteins: PAAR-like proteins in non-canonical Type VI secretion systems?

2016 ◽  
Vol 3 (11) ◽  
pp. 576-578
Author(s):  
Claire Lays ◽  
Eric Tannier ◽  
Thomas Henry
Keyword(s):  
Secretion Systems ◽  
Type Vi Secretion ◽  
Canonical Type

scholarly journals A post-translational modification of the sheath modulatesFrancisellatype VI secretion system assembly and function

2018 ◽  
Author(s):  
Jason Ziveri ◽  
Cerina Chhuon ◽  
Anne Jamet ◽  
Guénolé Prigent ◽  
Héloïse Rytter ◽  
...  
Keyword(s):  
Critical Role ◽  
Phosphorylation Site ◽  
Post Translational Modification ◽  
Secretion Systems ◽  
Post Translational Modifications ◽  
Type Vi Secretion ◽  
Sheath Formation ◽  
Canonical Type ◽  
The Stability ◽  
And Function

AbstractFrancisella tularensisis a facultative intracellular pathogen that causes the zoonotic disease tularemia in human and animal hosts. This bacterium possesses a non-canonical type VI secretion systems (T6SS) required for phagosomal escape and access to its replicative niche in the cytosol of infected macrophages. KCl stimulation has been previously used to trigger assembly and secretion of the Francisella T6SS in culture. We found that the amounts of essentially all the TSS6 proteins remained unchanged upon KCl stimulation. We therefore hypothesized that a post-translational modification might be involved in T6SS assembly. A whole cell phosphoproteomic analysis allowed us to identify a unique phosphorylation site on IglB, the TssC homologue and key component of the T6SS sheath. Importantly, the phosphorylated form of IglB was not present in the contracted sheath and 3D modeling indicated that the charge repulsion provoked by addition of a phosphogroup on tyrosine 139 was likely to weaken the stability of the sheath structure. Substitutions of the phosphorylatable residue of IglB (tyrosine 139) with alanine or with phosphomimetics prevented T6SS formation and totally impaired phagosomal escape. In contrast, the substitution with the non-phosphorylatable aromatic analog phenylalanine impaired but did not prevent phagosomal escape and cytosolic bacterial multiplication in J774-1 macrophages. Altogether these data suggest that phosphorylation of the sheath participates to T6SS disassembly. Post-translational modifications of the sheath may represent a previously unrecognized mechanism to finely modulate the dynamics of T6SS assembly-disassembly.Data are available via ProteomeXchange with identifier PXD012507.SynopsisFrancisellapossesses a non-canonical T6SS that is essential for efficient phagosomal escape and access to the cytosol of infected macrophages. KCl stimulation has been previously used to trigger assembly and secretion of the Francisella T6SS in culture. We found that KCl stimulation did not result in an increased production of TSS6 proteins. We therefore hypothesized that a post-translational modification might be involved in T6SS assembly. Using a global and site-specific phosphoproteomic analysis ofFrancisellawe identified a unique phosphorylation site on IglB, the TssC homologue and a key component of the T6SS contractile sheath. We show that this site plays a critical role in T6SS biogenesis and propose that phosphorylation may represent a new mechanism affecting the dynamics of sheath formation.

scholarly journals The Roles of Two Type VI Secretion Systems in Cronobacter sakazakii ATCC 12868

2018 ◽  
Vol 9 ◽  
Author(s):  
Min Wang ◽  
Hengchun Cao ◽  
Qian Wang ◽  
Tingting Xu ◽  
Xi Guo ◽  
...  
Keyword(s):  
Cronobacter Sakazakii ◽  
Secretion Systems ◽  
Type Vi Secretion

scholarly journals A family of T6SS antibacterial effectors related to L,D-transpeptidases targets the Peptidoglycan

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Stephanie Sibinelli de Sousa ◽  
Julia Takuno Hespanhol ◽  
Bruno Matsuyama ◽  
Stephane Mesnage ◽  
Gianlucca Nicastro ◽  
...  
Keyword(s):  
Cell Envelope ◽  
Point Mutations ◽  
Time Lapse ◽  
Secretion Systems ◽  
Bacterial Antagonism ◽  
New Family ◽  
Type Vi Secretion ◽  
Altered Cell ◽  
Bacterial Effectors ◽  
Insight Into

Type VI secretion systems (T6SSs) are contractile nanomachines widely used by bacteria to intoxicate competitors. Salmonella Typhimurium encodes a T6SS within the Salmonella pathogenicity island 6 (SPI-6) that is used during competition against species of the gut microbiota. We characterized a new SPI-6 T6SS antibacterial effector named Tlde1 (type VI L,D-transpeptidase effector 1). Tlde1 is toxic in target-cell periplasm and its toxicity is neutralized by co-expression with immunity protein Tldi1 (type VI L,D-transpeptidase immunity 1). Time-lapse microscopy revealed that intoxicated cells display altered cell division and lose cell envelope integrity. Bioinformatics analysis showed that Tlde1 is evolutionarily related to L,D-transpeptidases. Point mutations on conserved histidine121 and cysteine131 residues eliminated toxicity. Co-incubation of purified recombinant Tlde1 and peptidoglycan tetrapeptides showed that Tlde1 displays both L,D-carboxypeptidase activity by cleaving GM-tetrapeptides between meso-diaminopimelic acid3 and D-alanine4, and L,D-transpeptidase exchange activity by replacing D-alanine4 for a non-canonical D-amino acid. Tlde1 constitutes a new family of T6SS effectors widespread in Proteobacteria. This work increases our knowledge about the bacterial effectors used in interbacterial competitions and provides molecular insight into a new mechanism of bacterial antagonism.

scholarly journals Two Type VI Secretion Systems of Enterobacter cloacae Are Required for Bacterial Competition, Cell Adherence, and Intestinal Colonization

2020 ◽  
Vol 11 ◽  
Author(s):  
Jorge Soria-Bustos ◽  
Miguel A. Ares ◽  
Carlos A. Gómez-Aldapa ◽  
Jorge A. González-y-Merchand ◽  
Jorge A. Girón ◽  
...  
Keyword(s):  
Enterobacter Cloacae ◽  
Intestinal Colonization ◽  
Secretion Systems ◽  
Cell Adherence ◽  
Bacterial Competition ◽  
Type Vi Secretion

scholarly journals Type VI secretion systems of plant‐pathogenic Burkholderia glumae BGR1 play a functionally distinct role in interspecies interactions and virulence

2020 ◽  
Vol 21 (8) ◽  
pp. 1055-1069 ◽  
Author(s):  
Namgyu Kim ◽  
Jin Ju Kim ◽  
Inyoung Kim ◽  
Mohamed Mannaa ◽  
Jungwook Park ◽  
...  
Keyword(s):  
Interspecies Interactions ◽  
Secretion Systems ◽  
Burkholderia Glumae ◽  
Type Vi Secretion ◽  
Distinct Role

scholarly journals Paraburkholderia phymatum STM815 σ54 Controls Utilization of Dicarboxylates, Motility, and T6SS-b Expression

Nitrogen ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 81-98
Author(s):  
Martina Lardi ◽  
Yilei Liu ◽  
Sebastian Hug ◽  
Samanta Bolzan de Campos ◽  
Leo Eberl ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Nitrogenase Activity ◽  
Secretion Systems ◽  
Free Living ◽  
Major Life ◽  
Life Styles ◽  
Type Vi Secretion ◽  
Flagellar Biosynthesis ◽  
Free Living Conditions

Rhizobia have two major life styles, one as free-living bacteria in the soil, and the other as bacteroids within the root/stem nodules of host legumes where they convert atmospheric nitrogen into ammonia. In the soil, rhizobia have to cope with changing and sometimes stressful environmental conditions, such as nitrogen limitation. In the beta-rhizobial strain Paraburkholderia phymatum STM815, the alternative sigma factor σ54 (or RpoN) has recently been shown to control nitrogenase activity during symbiosis with Phaseolus vulgaris. In this study, we determined P. phymatum’s σ54 regulon under nitrogen-limited free-living conditions. Among the genes significantly downregulated in the absence of σ54, we found a C4-dicarboxylate carrier protein (Bphy_0225), a flagellar biosynthesis cluster (Bphy_2926-64), and one of the two type VI secretion systems (T6SS-b) present in the P. phymatum STM815 genome (Bphy_5978-97). A defined σ54 mutant was unable to grow on C4 dicarboxylates as sole carbon source and was less motile compared to the wild-type strain. Both defects could be complemented by introducing rpoNin trans. Using promoter reporter gene fusions, we also confirmed that the expression of the T6SS-b cluster is regulated by σ54. Accordingly, we show that σ54 affects in vitro competitiveness of P. phymatum STM815 against Paraburkholderia diazotrophica.

scholarly journals Divergent Control of Two Type VI Secretion Systems by RpoN in Pseudomonas aeruginosa

PLoS ONE ◽  
2013 ◽  
Vol 8 (10) ◽  
pp. e76030 ◽  
Author(s):  
Thibault G. Sana ◽  
Chantal Soscia ◽  
Céline M. Tonglet ◽  
Steve Garvis ◽  
Sophie Bleves
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Secretion Systems ◽  
Type Vi Secretion

scholarly journals Type VI secretion systems in plant-associated bacteria

2017 ◽  
Vol 20 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Patricia Bernal ◽  
María A. Llamas ◽  
Alain Filloux
Keyword(s):  
Secretion Systems ◽  
Associated Bacteria ◽  
Type Vi Secretion

scholarly journals Baseplate assembly of phage Mu: Defining the conserved core components of contractile-tailed phages and related bacterial systems

2016 ◽  
Vol 113 (36) ◽  
pp. 10174-10179 ◽  
Author(s):  
Carina R. Büttner ◽  
Yingzhou Wu ◽  
Karen L. Maxwell ◽  
Alan R. Davidson
Keyword(s):  
Type Vi Secretion System ◽  
Secretion Systems ◽  
Phage Mu ◽  
Self Defense ◽  
Type Vi Secretion ◽  
Essential Components ◽  
Core Components ◽  
Contractile Tail ◽  
Equivalent Structure ◽  
Conserved Core

Contractile phage tails are powerful cell puncturing nanomachines that have been co-opted by bacteria for self-defense against both bacteria and eukaryotic cells. The tail of phage T4 has long served as the paradigm for understanding contractile tail-like systems despite its greater complexity compared with other contractile-tailed phages. Here, we present a detailed investigation of the assembly of a “simple” contractile-tailed phage baseplate, that of Escherichia coli phage Mu. By coexpressing various combinations of putative Mu baseplate proteins, we defined the required components of this baseplate and delineated its assembly pathway. We show that the Mu baseplate is constructed through the independent assembly of wedges that are organized around a central hub complex. The Mu wedges are comprised of only three protein subunits rather than the seven found in the equivalent structure in T4. Through extensive bioinformatic analyses, we found that homologs of the essential components of the Mu baseplate can be identified in the majority of contractile-tailed phages and prophages. No T4-like prophages were identified. The conserved simple baseplate components were also found in contractile tail-derived bacterial apparatuses, such as type VI secretion systems, Photorhabdus virulence cassettes, and R-type tailocins. Our work highlights the evolutionary connections and similarities in the biochemical behavior of phage Mu wedge components and the TssF and TssG proteins of the type VI secretion system. In addition, we demonstrate the importance of the Mu baseplate as a model system for understanding bacterial phage tail-derived systems.

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