Structure and Activity of the Type VI Secretion System

Cherrak, Yassin; Flaugnatti, Nicolas; Durand, Éric; Journet, Laure; Cascales, Éric

doi:10.1128/9781683670285.ch26

Cited by 27 publications

(38 citation statements)

References 126 publications

(198 reference statements)

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“…It is composed of a membrane-spanning portion, a tube structure made of stacks of Hcp hexamer rings, and a tube-surrounding sheath. The sheath is composed of the two proteins VipA and VipB which, upon contraction, propels the inner tube out of the cell together with its effector-decorated tip proteins (VgrG and PAAR) (Zoued et al, 2014;Cherrak et al, 2019;Flaugnatti et al, 2020). Secreted Hcp therefore serves as an indicator of T6SS activity (Pukatzki et al 2006;Basler et al, 2012;Bröms et al, 2013;Kube et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Interbacterial competition and anti‐predatory behaviour of environmental Vibrio cholerae strains

Dörr

Blokesch

2020

Environmental Microbiology

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Vibrio cholerae isolates responsible for cholera pandemics represent only a small portion of the diverse strains belonging to this species. Indeed, most V. cholerae are encountered in aquatic environments. To better understand the emergence of pandemic lineages, it is crucial to discern what differentiates pandemic strains from their environmental relatives. Here, we studied the interaction of environmental V. cholerae with eukaryotic predators or competing bacteria and tested the contributions of the haemolysin and the type VI secretion system (T6SS) to those interactions. Both of these molecular weapons are constitutively active in environmental isolates but subject to tight regulation in the pandemic clade. We showed that several environmental isolates resist amoebal grazing and that this anti-grazing defense relies on the strains' T6SS and its actincross-linking domain (ACD)-containing tip protein. Strains lacking the ACD were unable to defend themselves against grazing amoebae but maintained high levels of T6SS-dependent interbacterial killing. We explored the latter phenotype through whole-genome sequencing of 14 isolates, which unveiled a wide array of novel T6SS effector and (orphan) immunity proteins. By combining these in silico predictions with experimental validations, we showed that highly similar but non-identical immunity proteins were insufficient to provide cross-immunity among those wild strains.

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Section: Introductionmentioning

confidence: 99%

Interbacterial competition and anti‐predatory behaviour of environmental Vibrio cholerae strains

Dörr

Blokesch

2020

Environmental Microbiology

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“…Finally, T6SSs were described only a decade ago, but in spite of this, their structure and mechanism have been deciphered in much detail quickly (Cherrak, Flaugnatti, Durand, Journet, & Cascales, ). The T6SS functions as a dynamic contractile phage tail‐like structure anchored in the bacterial cell envelope to deliver effectors directly into the target cell.…”

Section: Bacterial Injection Systems: All Roads Lead To Romementioning

confidence: 99%

Bacterial injection machines: Evolutionary diverse but functionally convergent

Bleves

Galán

Llosa

2020

Cellular Microbiology

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Many human pathogens use Type III, Type IV, and Type VI secretion systems to deliver effectors into their target cells. The contribution of these secretion systems to microbial virulence was the main focus of a workshop organised by the International University of Andalusia in Spain. The meeting addressed structure–function, substrate recruitment, and translocation processes, which differ widely on the different secretion machineries, as well as the nature of the translocated effectors and their roles in subverting the host cell. An excellent panel of worldwide speakers presented the state of the art of the field, highlighting the involvement of bacterial secretion in human disease and discussing mechanistic aspects of bacterial pathogenicity, which can provide the bases for the development of novel antivirulence strategies.

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“…Besides quorum sensing, other forms of intercellular communications play important roles in microbial interactions. These include secretion systems such as the type VI secretion system (T6SS) that is central to predator-prey interactions (Cherrak et al, 2019), extracellular or membrane vesicles that transfer a multitude of biomolecules including DNA and RNA (Bose et al, 2021) and appendages such as conjugative pili that mediates the horizontal transfer of DNA through conjugation (Virolle et al, 2020). This Research Topic not only covers intercellular communication among bacteria but also the gamut of processes that govern intracellular communication within each bacterial cell.…”

Section: Introductionmentioning

confidence: 99%