Bacterial mechanosensitive channels: progress towards an understanding of their roles in cell physiology ^☆

Highlights

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  Multiple mechanosensitive channels are found in most bacteria and archaea.

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  Channels are required to prevent loss of structural integrity during transitions from high to low osmolarity.

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  Channel diversity feeds into the detailed response of cells to hypo-osmotic stress.

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  There is growing evidence that organisms have evolved MS channels that reflect their niche.

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  Structural diversity may reflect roles additional to the observed function of protection of structural integrity.

Abstract

Bacterial mechanosensitive channels sense the changes in lateral tension in the bilayer of the cytoplasmic membrane generated by rapid water flow into the cell. Two major structural families are found widely distributed across bacteria and archaea: MscL and MscS. Our understanding of the mechanisms of gating has advanced rapidly through genetic analysis, structural biology and electrophysiology. It is only recently that the analysis of the physiological roles of the channels has kept pace with mechanistic studies. Recent advances have increased our understanding of the role of the channels in preventing structural perturbation during osmotic transitions and its relationship to water flow across the membrane. It is to these recent developments that this review is dedicated.