Tol-Pal system and Rgs proteins interact to promote unipolar growth and cell division in<i>Sinorhizobium meliloti</i>

Krol, Elizaveta; Yau, Hamish C. L.; Lechner, Marcus; Schäper, Simon; Bange, Gert; Vollmer, Waldemar; Becker, Anke

doi:10.1101/2020.02.13.948760

Cited by 2 publications

(2 citation statements)

References 71 publications

(90 reference statements)

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“…Apolipophorins and related Apolipoproteins are characterized by structurally flexible bundles of amphipathic α-helices that undergo conformational changes (SI Appendix, Fig. S1C) to mediate lipid interactions in eukarya (33)(34)(35), but related domains are also found in other large bacterial coiled-coil proteins (SI Appendix, Table S1) (36,37).…”

Section: Resultsmentioning

confidence: 99%

A bacterial cytolinker couples positioning of magnetic organelles to cell shape control

Pfeiffer

Toro-Nahuelpan

Awal

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Magnetotactic bacteria maneuver within the geomagnetic field by means of intracellular magnetic organelles, magnetosomes, which are aligned into a chain and positioned at midcell by a dedicated magnetosome-specific cytoskeleton, the “magnetoskeleton.” However, how magnetosome chain organization and resulting magnetotaxis is linked to cell shape has remained elusive. Here, we describe the cytoskeletal determinant CcfM (curvature-inducing coiled-coil filament interacting with the magnetoskeleton), which links the magnetoskeleton to cell morphology regulation in Magnetospirillum gryphiswaldense. Membrane-anchored CcfM localizes in a filamentous pattern along regions of inner positive-cell curvature by its coiled-coil motifs, and independent of the magnetoskeleton. CcfM overexpression causes additional circumferential localization patterns, associated with a dramatic increase in cell curvature, and magnetosome chain mislocalization or complete chain disruption. In contrast, deletion of ccfM results in decreased cell curvature, impaired cell division, and predominant formation of shorter, doubled chains of magnetosomes. Pleiotropic effects of CcfM on magnetosome chain organization and cell morphology are supported by the finding that CcfM interacts with the magnetoskeleton-related MamY and the actin-like MamK via distinct motifs, and with the cell shape-related cytoskeleton via MreB. We further demonstrate that CcfM promotes motility and magnetic alignment in structured environments, and thus likely confers a selective advantage in natural habitats of magnetotactic bacteria, such as aquatic sediments. Overall, we unravel the function of a prokaryotic cytoskeletal constituent that is widespread in magnetic and nonmagnetic spirilla-shaped Alphaproteobacteria.

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Section: Resultsmentioning

confidence: 99%

A bacterial cytolinker couples positioning of magnetic organelles to cell shape control

Pfeiffer

Toro-Nahuelpan

Awal

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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“…The expression of a set of S. meliloti genes related with the synthesis of the lipid A, the core polysaccharide and the O-antigen of LPS (acpXL,lpxXL,lpxK,ddhAB,kdsB,kdtA,lpsB,lpsCE,lpsS) (Lagares et al, 2001;Sharypova et al, 2003), as well as the lsrB gene that codes for a transcriptional regulator that activates the expression of LPS biosynthetic genes (Tang et al, 2014), were found to be up-regulated during predation. Likewise, the periplasmic TolB1 and the OM-anchored Pal lipoprotein, which are elements of the Tol/Pal system known to contribute to cell envelope integrity (Krol et al, 2020;Szczepaniak et al, 2020), showed increased expression. It was also remarkable that several genes involved in membrane lipid synthesis were upregulated (Figures 4A, B).…”

Section: Drastic Changes In the S Meliloti Cell Envelope During Preda...mentioning

confidence: 99%

Transcriptomic response of Sinorhizobium meliloti to the predatory attack of Myxococcus xanthus

et al. 2023

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Bacterial predation impacts microbial community structures, which can have both positive and negative effects on plant and animal health and on environmental sustainability. Myxococcus xanthus is an epibiotic soil predator with a broad range of prey, including Sinorhizobium meliloti, which establishes nitrogen-fixing symbiosis with legumes. During the M. xanthus-S. meliloti interaction, the predator must adapt its transcriptome to kill and lyse the target (predatosome), and the prey must orchestrate a transcriptional response (defensome) to protect itself against the biotic stress caused by the predatory attack. Here, we describe the transcriptional changes taking place in S. meliloti in response to myxobacterial predation. The results indicate that the predator induces massive changes in the prey transcriptome with up-regulation of protein synthesis and secretion, energy generation, and fatty acid (FA) synthesis, while down-regulating genes required for FA degradation and carbohydrate transport and metabolism. The reconstruction of up-regulated pathways suggests that S. meliloti modifies the cell envelop by increasing the production of different surface polysaccharides (SPSs) and membrane lipids. Besides the barrier role of SPSs, additional mechanisms involving the activity of efflux pumps and the peptide uptake transporter BacA, together with the production of H2O2 and formaldehyde have been unveiled. Also, the induction of the iron-uptake machinery in both predator and prey reflects a strong competition for this metal. With this research we complete the characterization of the complex transcriptional changes that occur during the M. xanthus-S. meliloti interaction, which can impact the establishment of beneficial symbiosis with legumes.

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Tol-Pal system and Rgs proteins interact to promote unipolar growth and cell division inSinorhizobium meliloti

Cited by 2 publications

References 71 publications

A bacterial cytolinker couples positioning of magnetic organelles to cell shape control

A bacterial cytolinker couples positioning of magnetic organelles to cell shape control

Transcriptomic response of Sinorhizobium meliloti to the predatory attack of Myxococcus xanthus

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