Ion-channel-like behavior in lipid bilayer membranes at the melting transition

Gallaher, Jill; Wodzinska, Katarzyna; Heimburg, Thomas; Bier, Martin

doi:10.1103/physreve.81.061925

Cited by 34 publications

(33 citation statements)

References 32 publications

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“…Since bilayer capacitance was measured throughout the experiment to ensure bilayer stability, we can neglect the possibility of ion leakage around the aperture. Earlier, fluctuation was also demonstrated by Heimburg et al, for phospholipids undergoing phase transitions [25,26]. However, the phospholipids used in our experiment do not undergo phase transition between-80 and 120°C as found from the supplier.…”

Section: Evidence Of Multiple Conductance States and Ion-channel Rsupporting

confidence: 77%

Creation and regulation of ion channels across reconstituted phospholipid bilayers generated by streptavidin-linked magnetite nanoparticles

Mohanta

Stava

et al. 2014

Phys. Rev. E

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In this work, we explore the nature of ion-channel-like conductance fluctuations across a reconstituted phospholipid bilayer due to insertion of ∼100 nm sized, streptavidin-linked magnetite nanoparticles under static magnetic fields (SMFs). For a fixed bias voltage, the frequency of current bursts increases with the application of SMFs. Apart from a closed conductance state G(0) (≤14 pS), we identify four major conductance states, with the lowest conductance level (G(1)) being ∼126 pS. The number of channel events at G(1) is found to be nearly doubled (as compared to G(0)) at a magnetic field of 70 G. The higher-order open states (e.g., 3G(1), 5G(1)) are generally observable at larger values of biasing voltage and magnetic field. When the SMF of 145 G is applied, the multiconductance states are resolved distinctly and are assigned to the simultaneous opening and closing of several independent states. The origin of the current bursts is due to the instantaneous mechanical actuation of streptavidin-linked MNP chains across the phospholipid bilayer. The voltage-controlled, magnetogated ion channels are promising for diagnoses and therapeutic applications of excitable membranes and other biological systems.

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Section: Evidence Of Multiple Conductance States and Ion-channel Rsupporting

confidence: 77%

Creation and regulation of ion channels across reconstituted phospholipid bilayers generated by streptavidin-linked magnetite nanoparticles

Mohanta

Stava

et al. 2014

Phys. Rev. E

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“…Since the experiments do not cover the shorter timescales anyway, this is the formula against which the obtained histograms are to be checked. This result is also shown in the references [4] and [5].…”

Section: /F Noise In Transmembrane Ion Traffic 421supporting

confidence: 80%

ION TRAFFIC THROUGH A CELL MEMBRANE — AND HOW ITS 1/f NOISE CONNECTS TO GAMBLER'S RUIN, CATALAN NUMBERS AND ZIPF'S LAW

Bier

Gallaher

2011

Fluct. Noise Lett.

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“…These lipid pores may spontaneously form and resemble certain electrophysiological features of protein pores [44]. However, at temperatures far from the T m , any lipid pores that form in membranes are known to fluctuate in size and eventually reseal due to the fluidity and dynamic nature of lipid molecules within the bilayer [18], [45].…”

Section: Discussionmentioning

confidence: 99%

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

Vanderlick

Beales

2013

PLoS ONE

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The release of cytochrome c (cyt c) from mitochondria is an important early step during cellular apoptosis, however the precise mechanism by which the outer mitochondrial membrane becomes permeable to these proteins is as yet unclear. Inspired by our previous observation of cyt c crossing the membrane barrier of giant unilamellar vesicle model systems, we investigate the interaction of cyt c with cardiolipin (CL)-containing membranes using the innovative droplet bilayer system that permits electrochemical measurements with simultaneous microscopy observation. We find that cyt c can permeabilize CL-containing membranes by induction of lipid pores in a dose-dependent manner, with membrane lysis eventually observed at relatively high (µM) cyt c concentrations due to widespread pore formation in the membrane destabilizing its bilayer structure. Surprisingly, as cyt c concentration is further increased, we find a regime with exceptionally high permeability where a stable membrane barrier is still maintained between droplet compartments. This unusual non-lytic state has a long lifetime (>20 h) and can be reversibly formed by mechanically separating the droplets before reforming the contact area between them. The transitions between behavioural regimes are electrostatically driven, demonstrated by their suppression with increasing ionic concentrations and their dependence on CL composition. While membrane permeability could also be induced by cationic PAMAM dendrimers, the non-lytic, highly permeable membrane state could not be reproduced using these synthetic polymers, indicating that details in the structure of cyt c beyond simply possessing a cationic net charge are important for the emergence of this unconventional membrane state. These unexpected findings may hold significance for the mechanism by which cyt c escapes into the cytosol of cells during apoptosis.

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Ion-channel-like behavior in lipid bilayer membranes at the melting transition

Cited by 34 publications

References 32 publications

Creation and regulation of ion channels across reconstituted phospholipid bilayers generated by streptavidin-linked magnetite nanoparticles

Creation and regulation of ion channels across reconstituted phospholipid bilayers generated by streptavidin-linked magnetite nanoparticles

ION TRAFFIC THROUGH A CELL MEMBRANE — AND HOW ITS 1/f NOISE CONNECTS TO GAMBLER'S RUIN, CATALAN NUMBERS AND ZIPF'S LAW

Lytic and Non-Lytic Permeabilization of Cardiolipin-Containing Lipid Bilayers Induced by Cytochrome c

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