The influence of static magnetic fields on mechanosensitive ion channel activity in artificial liposomes

AbstractMechanosensitive ion channels are membrane gated pores which are activated by mechanical stimuli. The focus of this study is on Piezo1, a newly discovered, large, mammalian, mechanosensitive ion channel, which has been linked to diseases such as dehydrated hereditary stomatocytosis (Xerocytosis) and lymphatic dysplasia. Here we utilize an established in-vitro artificial bilayer system to interrogate single Piezo1 channel activity. The droplet-hydrogel bilayer (DHB) system uniquely allows the simultaneous recording of electrical activity and fluorescence imaging of labelled protein. We successfully reconstituted fluorescently labelled Piezo1 ion channels in DHBs and verified activity using electrophysiology in the same system. We demonstrate successful insertion and activation of hPiezo1-GFP in bilayers of varying composition. Furthermore, we compare the Piezo1 bilayer reconstitution with measurements of insertion and activation of KcsA channels to reproduce the channel conductances reported in the literature. Together, our results showcase the use of DHBs for future experiments allowing simultaneous measurements of ion channel gating while visualising the channel proteins using fluorescence.

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Modulation of channel activity and gadolinium block of MscL by static magnetic fields

European Biophysics Journal ◽

10.1007/s00249-006-0109-z ◽

2006 ◽

Vol 36 (2) ◽

pp. 95-105 ◽

Cited By ~ 17

Author(s):

Evgeny Petrov ◽

Boris Martinac

Keyword(s):

Magnetic Fields ◽

Channel Activity ◽

Static Magnetic Fields

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Cell Membrane Pore Formation and Change in Ion Channel Activity in High-Gradient Magnetic Fields

IEEE Magnetics Letters ◽

10.1109/lmag.2017.2732361 ◽

2017 ◽

Vol 8 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Tatyana Polyakova ◽

Vitalii Zablotskii ◽

Alexandr Dejneka

Keyword(s):

Magnetic Fields ◽

Cell Membrane ◽

Ion Channel ◽

Pore Formation ◽

Channel Activity ◽

Membrane Pore ◽

High Gradient

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Analysis of the Mechanosensor Channel Functionality of TACAN

10.1101/2021.06.11.448078 ◽

2021 ◽

Author(s):

Yiming Niu ◽

Xiao Tao ◽

George Vaisey ◽

Paul Dominic B. Olinares ◽

Hanan Alwaseem ◽

...

Keyword(s):

Ion Channel ◽

Physiological Function ◽

Transmembrane Protein ◽

Dimensional Structure ◽

Mechanical Forces ◽

Channel Activity ◽

Fatty Acid Elongase ◽

Membrane Reconstitution ◽

3 Dimensional ◽

Mechanosensitive Ion Channel

Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the intent to understand how it senses mechanical forces and functions as an ion channel. Using cellular patch-recording methods we failed to identify mechanosensitive ion channel activity. Using membrane reconstitution methods we found that TACAN, at high protein concentrations, produces non-selective, heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. We determined the structure of TACAN using single particle cryo-EM and observe that it forms a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme-A co-factor, confirmed by mass spectrometry. The TACAN protomers are related in 3-dimensional structure to a fatty acid elongase, ELOVL. Whilst its physiological function remains unclear, we anticipate that TACAN is not a mechanosensitive ion channel.

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Analysis of the Mechanosensor Channel Functionality of TACAN

eLife ◽

10.7554/elife.71188 ◽

2021 ◽

Vol 10 ◽

Author(s):

Yiming Niu ◽

Xiao Tao ◽

George Vaisey ◽

Paul D B Olinares ◽

Hanan Alwaseem ◽

...

Keyword(s):

Ion Channel ◽

Physiological Function ◽

Transmembrane Protein ◽

Dimensional Structure ◽

Mechanical Forces ◽

Channel Activity ◽

Fatty Acid Elongase ◽

Membrane Reconstitution ◽

3 Dimensional ◽

Mechanosensitive Ion Channel

Mechanosensitive ion channels mediate transmembrane ion currents activated by mechanical forces. A mechanosensitive ion channel called TACAN was recently reported. We began to study TACAN with the intent to understand how it senses mechanical forces and functions as an ion channel. Using cellular patch-recording methods we failed to identify mechanosensitive ion channel activity. Using membrane reconstitution methods we found that TACAN, at high protein concentrations, produces heterogeneous conduction levels that are not mechanosensitive and are most consistent with disruptions of the lipid bilayer. We determined the structure of TACAN using single particle cryo-EM and observe that it forms a symmetrical dimeric transmembrane protein. Each protomer contains an intracellular-facing cleft with a coenzyme-A cofactor, confirmed by mass spectrometry. The TACAN protomers are related in 3-dimensional structure to a fatty acid elongase, ELOVL. Whilst its physiological function remains unclear, we anticipate that TACAN is not a mechanosensitive ion channel.

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