Coupled, circumferential motions of the cell wall synthesis machinery and MreB filaments in B. subtilis. Science

Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
Science (Impact Factor: 31.48). 06/2011; 333(6039):222-5. DOI: 10.1126/science.1203285
Source: PubMed

ABSTRACT Rod-shaped bacteria elongate by the action of cell wall synthesis complexes linked to underlying dynamic MreB filaments. To understand how the movements of these filaments relate to cell wall synthesis, we characterized the dynamics of MreB and the cell wall elongation machinery using high-precision particle tracking in Bacillus subtilis. We found that MreB and the elongation machinery moved circumferentially around the cell, perpendicular to its length, with nearby synthesis complexes and MreB filaments moving independently in both directions. Inhibition of cell wall synthesis by various methods blocked the movement of MreB. Thus, bacteria elongate by the uncoordinated, circumferential movements of synthetic complexes that insert radial hoops of new peptidoglycan during their transit, possibly driving the motion of the underlying MreB filaments.

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Available from: Ethan Clark Garner, Dec 28, 2013
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    • "After interaction with MreB, the Agl–Glt machinery together with MglA-GTP and MreB would become active and move directionally along its elusive track toward the lagging cell pole. It is unlikely that MreB itself forms the track because MreB does not appear to make continuous and polarized filaments in bacterial cells (Domínguez-Escobar et al., 2011; Garner et al., 2011; van Teeffelen et al., 2011) but instead MreB could act as a protein scaffold for assembly of the motility machinery. Recently, Nan et al. (2015) further suggested that MglA also regulates the directionality of the Agl motor; whether this is linked to the interaction with MreB remains to be explored. "
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    • "For localization to the cell wall, LytE interacts with the cytoskeletal protein MreBH (Carballido-López et al., 2006; Domínguez-Cuevas et al., 2013), of which the expression is downregulated in retentostat 2 only. Furthermore , the transcriptome revealed the repression in both retentostats of the genes mreD and rodZ which are part of the cell wall biosynthetic complex and involved in morphogenesis (Domínguez-Escobar et al., 2011; Garner et al., 2011; Muchová et al., 2013). "
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    • "However, some recent reports using high-resolution imaging indicate that either in E. coli or in B. subtilis MreB filaments do not run the length of the cell2122. Instead, they are actually composed of small dynamic patches that move around the cell circumference and are driven by the cell wall synthesis machinery472122232425. "
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