Genetic Screen for Potassium Leaky Small Mechanosensitive Channels (MscS) in Escherichia coli

Koprowski, Piotr; Grajkowski, Wojciech; Isacoff, Ehud Y.; Kubalski, Andrzej

doi:10.1074/jbc.m110.176131

Cited by 37 publications

(37 citation statements)

References 40 publications

(72 reference statements)

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“…These mutant channels almost invariably display instability of the open state consistent with loss of resistance within TM3b. Recent work that has deployed selection for increased gating at low tension to identify mutations from a random genetic pool supports the potential importance of these residues in stabilizing the closed state [39].…”

Section: Lipid-protein Interactions In Mscsmentioning

confidence: 95%

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Sensing bilayer tension: bacterial mechanosensitive channels and their gating mechanisms

Booth

Rasmussen

Edwards

et al. 2011

Biochemical Society Transactions

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Mechanosensitive channels sense and respond to changes in bilayer tension. In many respects, this is a unique property: the changes in membrane tension gate the channel, leading to the transient formation of open non-selective pores. Pore diameter is also high for the bacterial channels studied, MscS and MscL. Consequently, in cells, gating has severe consequences for energetics and homoeostasis, since membrane depolarization and modification of cytoplasmic ionic composition is an immediate consequence. Protection against disruption of cellular integrity, which is the function of the major channels, provides a strong evolutionary rationale for possession of such disruptive channels. The elegant crystal structures for these channels has opened the way to detailed investigations that combine molecular genetics with electrophysiology and studies of cellular behaviour. In the present article, the focus is primarily on the structure of MscS, the small mechanosensitive channel. The description of the structure is accompanied by discussion of the major sites of channel-lipid interaction and reasoned, but limited, speculation on the potential mechanisms of tension sensing leading to gating.

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Section: Lipid-protein Interactions In Mscsmentioning

confidence: 95%

“…The role of TM3b in MscS is controversial and our understanding of the roles played by this sequence is still evolving [37][38][39]. Genetic analysis has led to considerable speculation regarding the role of the Asn-Gly hinge and TM3b, which is dealt with below.…”

Section: Tm3bmentioning

confidence: 97%

Sensing bilayer tension: bacterial mechanosensitive channels and their gating mechanisms

Booth

Rasmussen

Edwards

et al. 2011

Biochemical Society Transactions

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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%

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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“…A structural comparison of EcMscS in the closed state with the EcMscS A106V mutant revealed striking conformational changes in the TM domain but not in the cytoplasmic region (11). However, subsequent physiological (15) and biophysical (16,17) studies suggest that the cytoplasmic region also undergoes a large conformational change when the channel is open.…”

mentioning

confidence: 99%

Structure and molecular mechanism of an anion-selective mechanosensitive channel of small conductance

Zhang

Wang

Feng

et al. 2012

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

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Mechanosensitive (MS) channels are universal cellular membrane pores. Bacterial MS channels, as typified by MS channel of small conductance (MscS) from Escherichia coli (EcMscS), release osmolytes under hypoosmotic conditions. MS channels are known to be ion selective to different extents, but the underlying mechanism remains poorly understood. Here we identify an anion-selective MscS channel from Thermoanaerobacter tengcongensis (TtMscS). The structure of TtMscS closely resembles that of EcMscS, but it lacks the large cytoplasmic equatorial portals found in EcMscS. In contrast, the cytoplasmic pore formed by the C-terminal β-barrel of TtMscS is larger than that of EcMscS and has a strikingly different pattern of electrostatic surface potential. Swapping the β-barrel region between TtMscS and EcMscS partially switches the ion selectivity. Our study defines the role of the β-barrel in the ion selection of an anion-selective MscS channel and provides a structural basis for understanding the ion selectivity of MscS channels.crystal structure | anion selection | cytoplasmic region | electrophysiology | single channel recording

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Genetic Screen for Potassium Leaky Small Mechanosensitive Channels (MscS) in Escherichia coli

Cited by 37 publications

References 40 publications

Sensing bilayer tension: bacterial mechanosensitive channels and their gating mechanisms

Sensing bilayer tension: bacterial mechanosensitive channels and their gating mechanisms

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

Structure and molecular mechanism of an anion-selective mechanosensitive channel of small conductance

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