Mechanosensitive channels in bacteria: signs of closure?

Booth, Ian R.; Edwards, Michelle D.; Black, Susan; Schümann, Ulrike; Miller, Samantha

doi:10.1038/nrmicro1659

Cited by 138 publications

(159 citation statements)

References 83 publications

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“…2C). Together, these results indicate that the molecular mechanism underlying the mechanosensitivity of MscS and MscL differs for the two channels in accordance with several previous reports (19)(20)(21)(22).…”

Section: Resultssupporting

confidence: 93%

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

Nomura

Cranfield

Deplazes

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

182

227

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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.Escherichia coli | giant spheroplasts | liposomes | amphipaths | pressure clamp

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Section: Resultssupporting

confidence: 93%

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

Nomura

Cranfield

Deplazes

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

182

227

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“…However, ATP binding and ATP hydrolysis were also reported to cause MD separation in MsbA and homologs (8,9,11,12,29). To investigate the effects of substrate binding on the conformation of MsbA at the MDs, we used our previously described cysteine reporter at the extracellular end of the MDs, A281C in MsbA-cl.…”

Section: Resultsmentioning

confidence: 99%

Substrate Binding Stabilizes a Pre-translocation Intermediate in the ATP-binding Cassette Transport Protein MsbA

Doshi

Veen

2013

Journal of Biological Chemistry

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Background: During substrate transport, ATP-binding cassette exporters switch between an inward-facing and an outward-facing state in a nucleotide-dependent fashion. Results: Substrate binding to bacterial MsbA initiates dimerization of nucleotide-binding domains without opening the membrane domains at their external side. Conclusion: Substrate binding to MsbA stabilizes an "inward-facing closed" pre-translocation state that binds ATP. Significance: Our observations suggest a fundamental mechanism by which substrates stimulate ATP hydrolysis.

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“…Indeed, together with the gene coding for the biosynthesis of the osmoprotectant trehalose synthesis, two membrane-based osmosensors, the mechanosensitive channel MscS and, to a lesser extent, the two-component sensor kinase KdpD as well as a potassium efflux protein were differentially expressed in the MESSAGE 2 space samples (Wood, 1999;Ballal et al, 2007;Gunasekera et al, 2008;Hurst et al, 2008). During a hypo-osmotic shock, that is, sudden reduction of the external osmolarity, induction of a mechanosensitive channel could act as an emergency safety valve (reviewed in Booth et al, 2007) and decreasing potassium influx (down-regulation Kdp-system) and increasing potassium efflux would help to adapt to this hypo-osmotic conditions. A disruption of the Figure 4 Comparison of significant genes expressed in the MESSAGE 2 (MSG2) and BASE-A related experiments.…”

Section: Discussionmentioning

confidence: 99%

Experimental design and environmental parameters affect Rhodospirillum rubrum S1H response to space flight

et al. 2009

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In view of long-haul space exploration missions, the European Space Agency initiated the MicroEcological Life Support System Alternative (MELiSSA) project targeting the total recycling of organic waste produced by the astronauts into oxygen, water and food using a loop of bacterial and higher plant bioreactors. In that purpose, the a-proteobacterium, Rhodospirillum rubrum S1H, was sent twice to the International Space Station and was analyzed post-flight using a newly developed R. rubrum whole genome oligonucleotide microarray and high throughput gel-free proteomics with Isotope-Coded Protein Label technology. Moreover, in an effort to identify a specific response of R. rubrum S1H to space flight, simulation of microgravity and space-ionizing radiation were performed on Earth under identical culture set-up and growth conditions as encountered during the actual space journeys. Transcriptomic and proteomic data were integrated and permitted to put forward the importance of medium composition and culture set-up on the response of the bacterium to space flight-related environmental conditions. In addition, we showed for the first time that a low dose of ionizing radiation (2 mGy) can induce a significant response at the transcriptomic level, although no change in cell viability and only a few significant differentially expressed proteins were observed. From the MELiSSA perspective, we could argue the effect of microgravity to be minimized, whereas R. rubrum S1H could be more sensitive to ionizing radiation during long-term space exploration mission.

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Mechanosensitive channels in bacteria: signs of closure?

Cited by 138 publications

References 83 publications

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

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

Substrate Binding Stabilizes a Pre-translocation Intermediate in the ATP-binding Cassette Transport Protein MsbA

Experimental design and environmental parameters affect Rhodospirillum rubrum S1H response to space flight

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