Differential effects of lipids and lyso-lipids on the mechanosensitivity of the mechanosensitive channels MscL and MscS

Nomura, Takeshi, Cranfield, Charles G., Deplazes, Evelyne, Owen, Dylan M., Macmillan, Alex, Battle, Andrew R., Constantine, Maryrose, Sokabe, Masahiro and Martinac, Boris (2012) Differential effects of lipids and lyso-lipids on the mechanosensitivity of the mechanosensitive channels MscL and MscS. Proceedings of the National Academy of Sciences of the United States of America, 109 22: 8770-8775. doi:10.1073/pnas.1200051109


Author Nomura, Takeshi
Cranfield, Charles G.
Deplazes, Evelyne
Owen, Dylan M.
Macmillan, Alex
Battle, Andrew R.
Constantine, Maryrose
Sokabe, Masahiro
Martinac, Boris
Title Differential effects of lipids and lyso-lipids on the mechanosensitivity of the mechanosensitive channels MscL and MscS
Journal name Proceedings of the National Academy of Sciences of the United States of America   Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2012-05-29
Sub-type Article (original research)
DOI 10.1073/pnas.1200051109
Volume 109
Issue 22
Start page 8770
End page 8775
Total pages 6
Place of publication Washington, United States
Publisher National Academy of Sciences
Collection year 2013
Language eng
Subject 1000 General
Abstract Mechanosensitive (MS) channels of small (MscS) and large (MscL) conductance are the major players in the protection of bacterial cells against hypoosmotic shock. Although a great deal is known about structure and function of these channels, much less is known about how membrane lipids may influence their mechanosensitivity and function. In this study, we use liposome coreconstitution to examine the effects of different types of lipids on MscS and MscL mechanosensitivity simultaneously using the patch-clamp technique and confocal microscopy. Fluorescence lifetime imaging (FLIM)-FRET microscopy demonstrated that coreconstitution of MscS and MscL led to clustering of these channels causing a significant increase in the MscS activation threshold. Furthermore, the MscL/MscS threshold ratio dramatically decreased in thinner compared with thicker bilayers and upon addition of cholesterol, known to affect the bilayer thickness, stiffness and pressure profile. In contrast, application of micromolar concentrations of lysophosphatidylcholine (LPC) led to an increase of the MscL/MscS threshold ratio. These data suggest that differences in hydrophobic mismatch and bilayer stiffness, change in transbilayer pressure profile, and close proximity of MscL and MscS affect the structural dynamics of both channels to a different extent. Our findings may have far-reaching implications for other types of ion channels and membrane proteins that, like MscL and MscS, may coexist in multiple molecular complexes and, consequently, have their activation characteristics significantly affected by changes in the lipid environment and their proximity to each other.
Keyword Amphipaths
Escherichia coli
Giant spheroplasts
Liposomes
Pressure clamp
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Non HERDC
School of Chemistry and Molecular Biosciences
 
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