The bacterial actin MreB rotates, and rotation depends on cell-wall assembly
- 8 September 2011
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 108 (38), 15822-15827
- https://doi.org/10.1073/pnas.1108999108
Abstract
Bacterial cells possess multiple cytoskeletal proteins involved in a wide range of cellular processes. These cytoskeletal proteins are dynamic, but the driving forces and cellular functions of these dynamics remain poorly understood. Eukaryotic cytoskeletal dynamics are often driven by motor proteins, but in bacteria no motors that drive cytoskeletal motion have been identified to date. Here, we quantitatively study the dynamics of the Escherichia coli actin homolog MreB, which is essential for the maintenance of rod-like cell shape in bacteria. We find that MreB rotates around the long axis of the cell in a persistent manner. Whereas previous studies have suggested that MreB dynamics are driven by its own polymerization, we show that MreB rotation does not depend on its own polymerization but rather requires the assembly of the peptidoglycan cell wall. The cell-wall synthesis machinery thus either constitutes a novel type of extracellular motor that exerts force on cytoplasmic MreB, or is indirectly required for an as-yet-unidentified motor. Biophysical simulations suggest that one function of MreB rotation is to ensure a uniform distribution of new peptidoglycan insertion sites, a necessary condition to maintain rod shape during growth. These findings both broaden the view of cytoskeletal motors and deepen our understanding of the physical basis of bacterial morphogenesis.Keywords
This publication has 30 references indexed in Scilit:
- Long helical filaments are not seen encircling cells in electron cryotomograms of rod-shaped bacteriaBiochemical and Biophysical Research Communications, 2011
- Mechanisms for maintaining cell shape in rod‐shaped Gram‐negative bacteriaMolecular Microbiology, 2011
- Myxobacteria gliding motility requires cytoskeleton rotation powered by proton motive forceProceedings of the National Academy of Sciences of the United States of America, 2011
- The Bacterial CytoskeletonAnnual Review of Genetics, 2010
- The Structure and Function of Bacterial Actin HomologsCold Spring Harbor Perspectives in Biology, 2010
- RodZ (YfgA) is required for proper assembly of the MreB actin cytoskeleton and cell shape in E. coliThe EMBO Journal, 2008
- Cell shape and cell-wall organization in Gram-negative bacteriaProceedings of the National Academy of Sciences of the United States of America, 2008
- Molecular organization of Gram-negative peptidoglycanProceedings of the National Academy of Sciences of the United States of America, 2008
- Super-resolution imaging in live Caulobacter crescentus cells using photoswitchable EYFPNature Methods, 2008
- Single molecules of the bacterial actin MreB undergo directed treadmilling motion in Caulobacter crescentusProceedings of the National Academy of Sciences of the United States of America, 2006