Sub-ten-nanometer heterogeneity of solid supported lipid membranes determined by solution atomic force microscopy

Ho, Chian Sing; Khadka, Nawal K.; Pan, Jianjun

doi:10.1016/j.bbamem.2015.11.001

Cited by 18 publications

(18 citation statements)

References 60 publications

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“…The interstice between the Lo domains is filled by the more bendable Ld phase, which minimizes the elastic energy. This theoretical conclusion seems to be confirmed by AFM experiments on a 4-component lipid mixture containing both POPC and DOPC, as above (DSPC has been replaced by brain-sphyngomyelin (bSM)) [29]. This systematic study points out the absence of "isolated disk-like domains" in flat geometry (where R → ∞) resulting from phase-dependent bending moduli, even at the 10 nm length-scale.…”

Section: Effect Of Volume Constraintsupporting

confidence: 71%

“…The plasma membrane also contains various inclusions made of peripheral or integral proteins [1,12]. Thanks to recent in vivo and in vitro experimental developments such as single particle tracking (SPT) [21,22,23], fluorescence (or Förster) resonance energy transfer (FRET) [20,24], atomic force microscopy (AFM) [25,26,27,28,29], superresolution microscopy techniques (STED, PALM, STORM, SIM, see the review [30]) or small-angle neutron scattering (SANS) [31,32,33], it has been observed and it is now widely agreed that cell membrane components are heterogeneously distributed, and are generically organized into functional lipid and protein sub-micrometric or nanoscopic domains (nanodomains for short). In particular, a common view pictures lipid nanodomains as lipid "rafts" [5,10,12,17,34], a consensual definition of which was formulated in 2006 [35].…”

Section: Introductionmentioning

confidence: 99%

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A rationale for mesoscopic domain formation in biomembranes

Destainville

Manghi

Cornet

2018

Preprint

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Cell plasma membranes display a dramatically rich structural complexity characterized by functional sub-wavelength domains with specific lipid and protein composition. Under favorable experimental conditions, patterned morphologies can also be observed in vitro on model systems such as supported membranes or lipid vesicles. Lipid mixtures separating in liquid-ordered and liquid-disordered phases below a demixing temperature play a pivotal role in this context. Protein-protein and protein-lipid interactions also contribute to membrane shaping by promoting small domains or clusters. Such phase separations displaying characteristic length-scales falling in-between the nanoscopic, molecular scale on the one hand and the macroscopic scale on the other hand, are named mesophases in soft condensed matter physics. In this review, we propose a classification of the diverse mechanisms leading to mesophase separation in biomembranes. We distinguish between mechanisms relying upon equilibrium thermodynamics and those involving out-of-equilibrium mechanisms, notably active membrane recycling. In equilibrium, we especially focus on the many mechanisms that dwell on an up-down symmetry breaking between the upper and lower bilayer leaflets. Symmetry breaking is an ubiquitous mechanism in condensed matter physics at the heart of several important phenomena. In the present case, it can be either spontaneous (domain buckling) or explicit, i.e., due to an external cause (global or local vesicle bending properties). Whenever possible, theoretical predictions and simulation results are confronted to experiments on model systems or living cells, which enables us to identify the most realistic mechanisms from a biological perspective.

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Section: Effect Of Volume Constraintsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

A rationale for mesoscopic domain formation in biomembranes

Destainville

Manghi

Cornet

2018

Preprint

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“…The planar bilayer exposed to E107-3 does not contain transmembrane pores, but rather resembles the fluctuation-like structures observed in ternary lipid mixtures [52, 62]. A correlation length ξ was used to describe the length scale of the fluctuation-like structures [52, 62].…”

Section: Resultsmentioning

confidence: 99%

“…A correlation length ξ was used to describe the length scale of the fluctuation-like structures [52, 62]. Correlation length has also been used to characterize the length scale of critical fluctuations observed in GUVs [63, 64].…”

Section: Resultsmentioning

confidence: 99%

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Khadka¹,

Teng²,

Cai³

et al. 2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Understanding how antimicrobial peptidomimetics interact with lipid membranes is important in battling multidrug resistant bacterial pathogens. We study the effects of a recently reported peptidomimetic on lipid bilayer structural and mechanical properties. The compound referred to as E107-3 is synthesized based on the acylated reduced amide scaffold and has been shown to exhibit good antimicrobial potency. Our vesicle leakage essay indicates that the compound increases lipid bilayer permeability. We use micropipette aspiration to explore the kinetic response of giant unilamellar vesicles (GUVs). Exposure to the compound causes the GUV protrusion length LP to spontaneously increase and then decrease, followed by GUV rupture. Solution atomic force microscopy (AFM) is used to visualize lipid bilayer structural modulation within a nanoscopic regime. Unlike melittin, which produces pore-like structures, the peptidomimetic compound is found to induce nanoscopic heterogeneous structures. Finally, we use AFM-based force spectroscopy to study the impact of the compound on lipid bilayer mechanical properties. We find that incremental addition of the compound to planar lipid bilayers results in a moderate decrease of the bilayer puncture force FP and a 39% decrease of the bilayer area compressibility modulus KA. To explain our experimental data, we propose a membrane interaction model encompassing disruption of lipid chain packing and extraction of lipid molecules. The later action mode is supported by our observation of a double-bilayer structure in the presence of fusogenic calcium ions.

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“…Experimental procedure for lipid bilayer preparation has been described before [33, 34]. Briefly, lipid small unilamellar vesicles (SUVs) in 10 mM HEPES pH 7.4 were generated by ultrasonication using a Sonic Dismembrator.…”

Section: Methodsmentioning

confidence: 99%

Polyglutamine aggregates impair lipid membrane integrity and enhance lipid membrane rigidity

Khadka

She

et al. 2016

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Lipid membranes are suggested as the primary target of amyloid aggregates. We study aggregates formed by a polyglutamine (polyQ) peptide, and their disruptive effect on lipid membranes. Using solution atomic force microscopy (AFM), we observe polyQ oligomers coexisting with short fibrils, which have a twisted morphology that likely corresponds to two intertwined oligomer strings. Fourier transform infrared spectroscopy reveals that the content of β-sheet enriched aggregates increases with incubation time. Using fluorescence microscopy, we find that exposure to polyQ aggregates results in deflated morphology of giant unilamellar vesicles. PolyQ aggregates induced membrane disruption is further substantiated by time-dependent calcein leakage from the interior to the exterior of lipid vesicles. Detailed structural and mechanical perturbations of lipid membranes are revealed by solution AFM. We find that membrane disruption by polyQ aggregates proceeds by a two-step process, involving partial and full disruption. In addition to height contrast, the resulting partially and fully disrupted bilayers have distinct rigidity and adhesion force properties compared to the intact bilayer. Specifically, the bilayer rigidity increases as the intact bilayer becomes partially and fully disrupted. Surprisingly, the adhesion force first decreases and then increases during the disruption process. By resolving individual fibrils deposited on bilayer surface, we show that both the length and the number of fibrils can increase with incubation time. Our results highlight that membrane disruption could be the molecular basis of polyQ aggregates induced cytotoxicity.

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Sub-ten-nanometer heterogeneity of solid supported lipid membranes determined by solution atomic force microscopy

Cited by 18 publications

References 60 publications

A rationale for mesoscopic domain formation in biomembranes

A rationale for mesoscopic domain formation in biomembranes

Modulation of lipid membrane structural and mechanical properties by a peptidomimetic derived from reduced amide scaffold

Polyglutamine aggregates impair lipid membrane integrity and enhance lipid membrane rigidity

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