How do mechanosensitive channels sense membrane tension?

Tim Rasmussen

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Mechanosensitive (MS) channels provide protection against hypo-osmotic shock in bacteria whereas eukaryotic MS channels fulfil a multitude of important functions beside osmoregulation. Interactions with the membrane lipids are responsible for the sensing of mechanical force for most known MS channels. It emerged recently that not only prokaryotic, but also eukaryotic, MS channels are able to directly sense the tension in the membrane bilayer without any additional cofactor. If the membrane is solely viewed as a continuous medium with specific anisotropic physical properties, the sensitivity towards tension changes can be explained as result of the hydrophobic coupling between membrane and transmembrane (TM) regions of the channel. The increased cross-sectional area of the MS channel in the active conformation and elastic deformations of the membrane close to the channel have been described as important factors. However, recent studies suggest that molecular interactions of lipids with the channels could play an important role in mechanosensation. Pockets in between TM helices were identified in the MS channel of small conductance (MscS) and YnaI that are filled with lipids. Less lipids are present in the open state of MscS than the closed according to MD simulations. Thus it was suggested that exclusion of lipid fatty acyl chains from these pockets, as a consequence of increased tension, would trigger gating. Similarly, in the eukaryotic MS channel TRAAK it was found that a lipid chain blocks the conducting path in the closed state. The role of these specific lipid interactions in mechanosensation are highlighted in this review.
Original languageEnglish
Pages (from-to)1019-1025
Number of pages7
JournalBiochemical Society Transactions
Volume44
Issue number4
DOIs
Publication statusPublished - 15 Aug 2016

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Ion Channels
Membranes
Lipids
Osmoregulation
Molecular interactions
Osmotic Pressure
Elastic deformation
Membrane Lipids
Conformations
Bacteria
Physical properties

Keywords

  • bacterial stress response
  • fluorescence spectroscopy
  • lipid-protein interactions
  • mechanosensitive channels

Cite this

How do mechanosensitive channels sense membrane tension? / Rasmussen, Tim.

In: Biochemical Society Transactions, Vol. 44, No. 4, 15.08.2016, p. 1019-1025.

Research output: Contribution to journalArticle

Rasmussen, Tim. / How do mechanosensitive channels sense membrane tension?. In: Biochemical Society Transactions. 2016 ; Vol. 44, No. 4. pp. 1019-1025.
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