Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii
The type VI secretion system (T6SS) is a sophisticated, contact-dependent nanomachine involved in interbacterial competition. To function effectively, the T6SS must penetrate the membranes of both attacker and target bacteria. Structures associated with the cell envelope, like polysaccharides chains...
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| Format: | Article |
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eLife Sciences Publications Ltd
2025-01-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/101032 |
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| author | Nicolas Flaugnatti Loriane Bader Mary Croisier-Coeytaux Melanie Blokesch |
| author_facet | Nicolas Flaugnatti Loriane Bader Mary Croisier-Coeytaux Melanie Blokesch |
| author_sort | Nicolas Flaugnatti |
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| description | The type VI secretion system (T6SS) is a sophisticated, contact-dependent nanomachine involved in interbacterial competition. To function effectively, the T6SS must penetrate the membranes of both attacker and target bacteria. Structures associated with the cell envelope, like polysaccharides chains, can therefore introduce spatial separation and steric hindrance, potentially affecting the efficacy of the T6SS. In this study, we examined how the capsular polysaccharide (CPS) of Acinetobacter baumannii affects T6SS’s antibacterial function. Our findings show that the CPS confers resistance against T6SS-mediated assaults from rival bacteria. Notably, under typical growth conditions, the presence of the surface-bound capsule also reduces the efficacy of the bacterium’s own T6SS. This T6SS impairment is further enhanced when CPS is overproduced due to genetic modifications or antibiotic treatment. Furthermore, we demonstrate that the bacterium adjusts the level of the T6SS inner tube protein Hcp according to its secretion capacity, by initiating a degradation process involving the ClpXP protease. Collectively, our findings contribute to a better understanding of the dynamic relationship between T6SS and CPS and how they respond swiftly to environmental challenges. |
| format | Article |
| id | doaj-art-d7708703a81f4bfa9b0d8854c93583f3 |
| institution | Kabale University |
| issn | 2050-084X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | eLife Sciences Publications Ltd |
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| series | eLife |
| spelling | doaj-art-d7708703a81f4bfa9b0d8854c93583f32025-01-14T11:49:21ZengeLife Sciences Publications LtdeLife2050-084X2025-01-011410.7554/eLife.101032Capsular polysaccharide restrains type VI secretion in Acinetobacter baumanniiNicolas Flaugnatti0https://orcid.org/0000-0002-6073-3340Loriane Bader1Mary Croisier-Coeytaux2Melanie Blokesch3https://orcid.org/0000-0002-7024-1489Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, SwitzerlandLaboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, SwitzerlandBioelectron Microscopy Core Facility, School of Life Sciences, Station 19, EPFL-SV-PTBIOEM, Ecole Polytechnique Fédérale de Lausanne, Lausanne, SwitzerlandLaboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, SwitzerlandThe type VI secretion system (T6SS) is a sophisticated, contact-dependent nanomachine involved in interbacterial competition. To function effectively, the T6SS must penetrate the membranes of both attacker and target bacteria. Structures associated with the cell envelope, like polysaccharides chains, can therefore introduce spatial separation and steric hindrance, potentially affecting the efficacy of the T6SS. In this study, we examined how the capsular polysaccharide (CPS) of Acinetobacter baumannii affects T6SS’s antibacterial function. Our findings show that the CPS confers resistance against T6SS-mediated assaults from rival bacteria. Notably, under typical growth conditions, the presence of the surface-bound capsule also reduces the efficacy of the bacterium’s own T6SS. This T6SS impairment is further enhanced when CPS is overproduced due to genetic modifications or antibiotic treatment. Furthermore, we demonstrate that the bacterium adjusts the level of the T6SS inner tube protein Hcp according to its secretion capacity, by initiating a degradation process involving the ClpXP protease. Collectively, our findings contribute to a better understanding of the dynamic relationship between T6SS and CPS and how they respond swiftly to environmental challenges.https://elifesciences.org/articles/101032Acinetobacter baumanniicapsular polysaccharideimmunity protein-independent protectiontype VI secretion |
| spellingShingle | Nicolas Flaugnatti Loriane Bader Mary Croisier-Coeytaux Melanie Blokesch Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii eLife Acinetobacter baumannii capsular polysaccharide immunity protein-independent protection type VI secretion |
| title | Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii |
| title_full | Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii |
| title_fullStr | Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii |
| title_full_unstemmed | Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii |
| title_short | Capsular polysaccharide restrains type VI secretion in Acinetobacter baumannii |
| title_sort | capsular polysaccharide restrains type vi secretion in acinetobacter baumannii |
| topic | Acinetobacter baumannii capsular polysaccharide immunity protein-independent protection type VI secretion |
| url | https://elifesciences.org/articles/101032 |
| work_keys_str_mv | AT nicolasflaugnatti capsularpolysacchariderestrainstypevisecretioninacinetobacterbaumannii AT lorianebader capsularpolysacchariderestrainstypevisecretioninacinetobacterbaumannii AT marycroisiercoeytaux capsularpolysacchariderestrainstypevisecretioninacinetobacterbaumannii AT melanieblokesch capsularpolysacchariderestrainstypevisecretioninacinetobacterbaumannii |