Mechanical strain sensing implicated in cell shape recovery in Escherichia coli
Felix Wong1, Lars D Renner2,3, Gizem Özbaykal4
1School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature Microbiology
|July 25, 2017
Summary
Mechanical strain sensing, not MreB, explains how bacteria like Escherichia coli maintain their rod shape. This study reveals how cell wall mechanics guide bacterial morphology and recovery from bending.
Area of Science:
- Microbiology
- Biophysics
- Cell Biology
Background:
- Bacterial shape is determined by peptidoglycan cell walls, involving complex dynamics across multiple length scales.
- Maintaining stable rod-like bacterial morphologies is challenging due to incomplete understanding of growth-elasticity feedback in cell walls.
Purpose of the Study:
- To investigate the impact of mechanical strain on bacterial cell shape.
- To model the mechanical strains from cell wall bending and differential growth.
- To understand the mechanisms regulating bacterial shape and recovery from deformation.
Main Methods:
- Modelling mechanical strains caused by cell wall bending and differential growth.
- Growing filamentous Escherichia coli in microchambers to observe shape recovery.
- Measuring MreB localization during confinement and shape recovery.
Main Results:
- Spatial coupling of growth to high mechanical strain explains plastic response to bending and predicts straightening rate.
- Escherichia coli cells recovered native rod shapes post-confinement at a rate matching theoretical predictions.
- MreB localization did not account for the observed plastic response or straightening rate.
Conclusions:
- Mechanical strain sensing, mediated by uncharacterized elongasome components, is crucial for robust shape regulation in E. coli.
- The study implicates mechanical feedback in bacterial morphogenesis, moving beyond explanations solely based on cytoskeletal elements like MreB.
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