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Processive movement of MreB-associated cell wall biosynthetic complexes in bacteria
Julia Domínguez-Escobar1, Arnaud Chastanet, Alvaro H Crevenna
1Max Planck Institute of Biochemistry, Martinsried, Germany.
Science (New York, N.Y.)
|June 4, 2011
Summary
In Bacillus subtilis, MreB proteins form dynamic patches, not helical filaments, that move along cell walls. This movement is powered by cell wall synthesis, guiding bacterial shape determination.
Area of Science:
- Bacterial cell biology
- Microbial morphogenesis
- Cytoskeletal dynamics
Background:
- Rod-shaped bacteria rely on peptidoglycan cell walls and MreB cytoskeletons for shape.
- Existing models propose helical MreB filaments guide cell wall synthesis.
Purpose of the Study:
- To visualize the dynamic relationship between MreB and cell wall synthesis in live Bacillus subtilis.
- To challenge or refine the prevailing model of MreB function in cell shape determination.
Main Methods:
- Total internal reflection fluorescence microscopy (TIRFm) was employed.
- Live Bacillus subtilis cells were observed during exponential growth.
Main Results:
- MreB proteins assembled into discrete, motile patches, not helical structures.
- These MreB patches moved along peripheral tracks perpendicular to the cell axis.
- Cell wall synthesis powered patch motility, with MreB restricting diffusion and orienting movement.
Conclusions:
- The prevailing model of helical MreB filaments is not supported for Bacillus subtilis during growth.
- MreB functions in dynamic patches that are coupled to peptidoglycan synthesis for cell elongation.
- This provides a new perspective on the mechanisms of bacterial cell shape maintenance.
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