Selectivity mechanism of the mechanosensitive channel MscS revealed by probing channel subconducting states

Cox, Charles D.; Nomura, Takeshi; Ziegler, Christina; Campbell, Anthony K.; Wann, K. T.; Martinac, Boris

doi:10.1038/ncomms3137

Cited by 80 publications

(71 citation statements)

References 55 publications

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“…In the presence of mannitol, distinct MscS single or multiple channels (n=6 ; Table S1) were observed with a γ = 630±30 pS; no activity was observed without osmotic stress (n=4). The MscS activity induced is 'flickery' in nature, in accordance with previous reports in pure lipid bilayers (Ridone et al, 2015) and did not display noticeable inactivation (Cox et al, 2013).…”

Section: Activation Of Piezo1 Upon Stimulation By An Osmotic Gradientsupporting

confidence: 78%

Piezo1 Channels are Inherently Mechanosensitive

Syeda

2017

Biophysical Journal

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The conversion of mechanical force to chemical signals is critical for many biological processes, including the sense of touch, pain, and hearing. Mechanosensitive ion channels play a key role in sensing the mechanical stimuli experienced by various cell types, and are present in bacteria to mammals. Bacterial mechanosensitive channels are characterized thoroughly, but less is known about their counterparts in vertebrates. Piezos have been recently established as ion channels required for mechanotransduction in disparate cell types in vitro and in vivo. Overexpression of Piezos in heterologous cells gives rise to large mechanically activated currents; however, it is unclear whether Piezos are inherently mechanosensitive or rely on alternate cellular components to sense mechanical stimuli. Here we show that mechanical perturbations of the lipid bilayer alone are sufficient to activate Piezo channels, illustrating their innate ability as molecular force transducers. eTOCCorrespondence and requests for materials should be addressed to R.S. (ruhma@scripps.edu). * Lead Contact: Ruhma Syeda (ruhma@scripps.edu) Author Contributions R.S and A.P. designed the experiments, and wrote the manuscript. R.S, M.F, J.K conducted Piezo1 purification with the help from J.S. R.S conducted electrical recordings and performed analysis. C.D.C. and B.M. provided MscS protein, analyzed bilayer tension data and wrote the manuscript.Author Information: The authors declare no competing interests.Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access

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Section: Activation Of Piezo1 Upon Stimulation By An Osmotic Gradientsupporting

confidence: 78%

Piezo1 Channels are Inherently Mechanosensitive

Syeda

2017

Biophysical Journal

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“…Mutations outside the membrane-spanning pore of bacterial MscS homologs alter channel conductance Cox et al, 2013) and gating properties (Nomura et al, 2008;Vásquez et al, 2008;Belyy et al, 2010;Koprowski et al, 2011). If the MSL10 N-terminal domain interacts with the rest of the channel, the mutation of seven charged amino acids could alter channel properties.…”

Section: Preventing or Mimicking Phosphorylation Of The Msl10 N-termimentioning

confidence: 99%

“…Each subunit contains three transmembrane (TM) helices, with the third TM helix of each monomer lining the pore. This pore extends into the vestibule of a large cytoplasmic chamber that may serve to influence the composition of ions that pass through the channel (Gamini et al, 2011;Zhang et al, 2012;Cox et al, 2013). Along with several other MS ion channels in the bacterial membrane, MscS facilitates survival of hypo-osmotic shock by releasing osmolytes when membrane tension increases beyond a certain threshold and is frequently referred to as an "osmotic safety valve" (Blount and Moe, 1999;Levina et al, 1999;Sotomayor et al, 2006;Boer et al, 2011;Reuter et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Arabidopsis MSL10 Has a Regulated Cell Death Signaling Activity That Is Separable from Its Mechanosensitive Ion Channel Activity

et al. 2014

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Members of the MscS superfamily of mechanosensitive ion channels function as osmotic safety valves, releasing osmolytes under increased membrane tension. MscS homologs exhibit diverse topology and domain structure, and it has been proposed that the more complex members of the family might have novel regulatory mechanisms or molecular functions. Here, we present a study of MscS-Like (MSL)10 from Arabidopsis thaliana that supports these ideas. High-level expression of MSL10-GFP in Arabidopsis induced small stature, hydrogen peroxide accumulation, ectopic cell death, and reactive oxygen species-and cell death-associated gene expression. Phosphomimetic mutations in the MSL10 N-terminal domain prevented these phenotypes. The phosphorylation state of MSL10 also regulated its ability to induce cell death when transiently expressed in Nicotiana benthamiana leaves but did not affect subcellular localization, assembly, or channel behavior. Finally, the N-terminal domain of MSL10 was sufficient to induce cell death in tobacco, independent of phosphorylation state. We conclude that the plant-specific N-terminal domain of MSL10 is capable of inducing cell death, this activity is regulated by phosphorylation, and MSL10 has two separable activities-one as an ion channel and one as an inducer of cell death. These findings further our understanding of the evolution and significance of mechanosensitive ion channels.

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“…MscL | azolectin | electrophysiology | finite element modeling L iposome reconstitution has been used for both functional and structural studies of bacterial mechanosensitive (MS) channels (MscL and MscS) for many years (1)(2)(3)(4) and also more recently for the study of eukaryotic MS channels (5)(6)(7)(8). Most frequently azolectin, a crude extract of phospholipids from animal and plant tissue consisting mainly of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) (9), has been used for liposome preparations.…”

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confidence: 99%

Biophysical implications of lipid bilayer rheometry for mechanosensitive channels

Bavi

Nakayama

Bavi

et al. 2014

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

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The lipid bilayer plays a crucial role in gating of mechanosensitive (MS) channels. Hence it is imperative to elucidate the rheological properties of lipid membranes. Herein we introduce a framework to characterize the mechanical properties of lipid bilayers by combining micropipette aspiration (MA) with theoretical modeling. Our results reveal that excised liposome patch fluorometry is superior to traditional cell-attached MA for measuring the intrinsic mechanical properties of lipid bilayers. The computational results also indicate that unlike the uniform bilayer tension estimated by Laplace's law, bilayer tension is not uniform across the membrane patch area. Instead, the highest tension is seen at the apex of the patch and the lowest tension is encountered near the pipette wall. More importantly, there is only a negligible difference between the stress profiles of the outer and inner monolayers in the cellattached configuration, whereas a substantial difference (∼30%) is observed in the excised configuration. Our results have farreaching consequences for the biophysical studies of MS channels and ion channels in general, using the patch-clamp technique, and begin to unravel the difference in activity seen between MS channels in different experimental paradigms.MscL | azolectin | electrophysiology | finite element modeling L iposome reconstitution has been used for both functional and structural studies of bacterial mechanosensitive (MS) channels (MscL and MscS) for many years (1-4) and also more recently for the study of eukaryotic MS channels (5-8). Most frequently azolectin, a crude extract of phospholipids from animal and plant tissue consisting mainly of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI) (9), has been used for liposome preparations. Given the frequent use of azolectin bilayers for the study of MS channels and the importance of protein-lipid interactions in MS channel gating it is imperative to consider the best way to accurately calculate and assess its material properties. This is also essential for studies of voltage-and ligand-gated ion channels as the activity of these proteins can also be modulated by membrane tension (6-8, 10-12).The mechanical properties of different types of lipids have been studied extensively using the micropipette aspiration (MA) approach (13-18). These experiments have shown that the mechanical properties of lipids differ considerably and that lipid bilayers exhibit elastic behavior (14,15,18,19). The MA technique is versatile and has the advantage of exerting a wide range of aspiration pressures on a specific portion of a bilayer (20-23).Here we use this technique in combination with finite-element (FE) simulation to examine in depth the mechanical properties of azolectin bilayers in both cell-attached and excised patch configurations (SI Materials and Methods). It is widely known that lipid behavior is vastly different at low (<0.5 mN/m) compared with high tensions, due to thermal shape fluctuations (24). Given that the m...

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Selectivity mechanism of the mechanosensitive channel MscS revealed by probing channel subconducting states

Cited by 80 publications

References 55 publications

Piezo1 Channels are Inherently Mechanosensitive

Piezo1 Channels are Inherently Mechanosensitive

Arabidopsis MSL10 Has a Regulated Cell Death Signaling Activity That Is Separable from Its Mechanosensitive Ion Channel Activity

Biophysical implications of lipid bilayer rheometry for mechanosensitive channels

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