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- Cabeen, Matthew T., et al.
(författare)
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Bacterial cell curvature through mechanical control of cell growth
- 2009
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Ingår i: EMBO Journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 28:9, s. 1208-1219
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Tidskriftsartikel (refereegranskat)abstract
- The cytoskeleton is a key regulator of cell morphogenesis. Crescentin, a bacterial intermediate filament-like protein, is required for the curved shape of Caulobacter crescentus and localizes to the inner cell curvature. Here, we show that crescentin forms a single filamentous structure that collapses into a helix when detached from the cell membrane, suggesting that it is normally maintained in a stretched configuration. Crescentin causes an elongation rate gradient around the circumference of the sidewall, creating a longitudinal cell length differential and hence curvature. Such curvature can be produced by physical force alone when cells are grown in circular microchambers. Production of crescentin in Escherichia coli is sufficient to generate cell curvature. Our data argue for a model in which physical strain borne by the crescentin structure anisotropically alters the kinetics of cell wall insertion to produce curved growth. Our study suggests that bacteria may use the cytoskeleton for mechanical control of growth to alter morphology. The EMBO Journal (2009) 28, 1208-1219. doi: 10.1038/emboj.2009.61; Published online 12 March 2009
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| 2. |
- Cabeen, Matthew T., et al.
(författare)
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Mutations in the Lipopolysaccharide Biosynthesis Pathway Interfere with Crescentin-Mediated Cell Curvature in Caulobacter crescentus
- 2010
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Ingår i: Journal of Bacteriology. - 0021-9193 .- 1098-5530. ; 192:13, s. 3368-3378
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial cell morphogenesis requires coordination among multiple cellular systems, including the bacterial cytoskeleton and the cell wall. In the vibrioid bacterium Caulobacter crescentus, the intermediate filament-like protein crescentin forms a cell envelope-associated cytoskeletal structure that controls cell wall growth to generate cell curvature. We undertook a genetic screen to find other cellular components important for cell curvature. Here we report that deletion of a gene (wbqL) involved in the lipopolysaccharide (LPS) biosynthesis pathway abolishes cell curvature. Loss of WbqL function leads to the accumulation of an aberrant O-polysaccharide species and to the release of the S layer in the culture medium. Epistasis and microscopy experiments show that neither S-layer nor O-polysaccharide production is required for curved cell morphology per se but that production of the altered O-polysaccharide species abolishes cell curvature by apparently interfering with the ability of the crescentin structure to associate with the cell envelope. Our data suggest that perturbations in a cellular pathway that is itself fully dispensable for cell curvature can cause a disruption of cell morphogenesis, highlighting the delicate harmony among unrelated cellular systems. Using the wbqL mutant, we also show that the normal assembly and growth properties of the crescentin structure are independent of its association with the cell envelope. However, this envelope association is important for facilitating the local disruption of the stable crescentin structure at the division site during cytokinesis.
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