Single-cell census of mechanosensitive channels in living bacteria
| Autor: | Rob Phillips, Maja Bialecka-Fornal, Heun Jin Lee, Hannah A. DeBerg, Chris S. Gandhi |
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| Rok vydání: | 2011 |
| Předmět: |
Cell physiology
Proteomics Osmotic shock Cell Blotting Western lcsh:Medicine Biology Mechanotransduction Cellular Biochemistry Microbiology Ion Channels 03 medical and health sciences Model Organisms Molecular Cell Biology medicine Escherichia coli Mechanotransduction lcsh:Science Ion channel 030304 developmental biology 0303 health sciences Multidisciplinary Osmotic concentration 030306 microbiology Escherichia coli Proteins lcsh:R Proteins Bacteriology Water-Electrolyte Balance Cell biology Electrophysiology medicine.anatomical_structure Microscopy Fluorescence Prokaryotic Models lcsh:Q Mechanosensitive channels Research Article |
| Zdroj: | PLoS ONE PLoS ONE, Vol 7, Iss 3, p e33077 (2012) |
| ISSN: | 1932-6203 |
| Popis: | Bacteria are subjected to a host of different environmental stresses. One such insult occurs when cells encounter changes in the osmolarity of the surrounding media resulting in an osmotic shock. In recent years, a great deal has been learned about mechanosensitive (MS) channels which are thought to provide osmoprotection in these circumstances by opening emergency release valves in response to membrane tension. However, even the most elementary physiological parameters such as the number of MS channels per cell, how MS channel expression levels influence the physiological response of the cells, and how this mean number of channels varies from cell to cell remain unanswered. In this paper, we make a detailed quantitative study of the expression of the mechanosensitive channel of large conductance (MscL) in different media and at various stages in the growth history of bacterial cultures. Using both quantitative fluorescence microscopy and quantitative Western blots our study complements earlier electrophysiology-based estimates and results in the following key insights: i) the mean number of channels per cell is much higher than previously estimated, ii) measurement of the single-cell distributions of such channels reveals marked variability from cell to cell and iii) the mean number of channels varies under different environmental conditions. The regulation of MscL expression displays rich behaviors that depend strongly on culturing conditions and stress factors, which may give clues to the physiological role of MscL. The number of stress-induced MscL channels and the associated variability have far reaching implications for the in vivo response of the channels and for modeling of this response. As shown by numerous biophysical models, both the number of such channels and their variability can impact many physiological processes including osmoprotection, channel gating probability, and channel clustering. |
| Databáze: | OpenAIRE |
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