Modelling the dynamics of vesicle reshaping and scission under osmotic shocks

Campos, Christian Vanhille; Šarić, Anđela

doi:10.1101/2020.11.16.384602

Cited by 4 publications

(4 citation statements)

References 42 publications

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“…4e). This suggests that the enveloping membrane of the superstructure protects the colony from the initial osmotic shock by acting as a barrier, and reshapes itself in response 44 , possibly also relieving membrane tension by drawing additional lipid material from the attached multilamellar reservoir. It was shown recently that hypertonic conditions cause the compression of magnetically-assembled vesicle clusters and decrease the permeability into the cluster 12 .…”

Section: Resultsmentioning

confidence: 99%

Colony-like Protocell Superstructures

Spustová

Katke

Villalmanzo

et al. 2021

Preprint

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We report the formation, growth, and dynamics of model protocell superstructures on solid surfaces, resembling single cell colonies. These structures, consisting of several layers of lipidic compartments enveloped in a dome-shaped outer lipid bilayer, emerged as a result of spontaneous shape transformation of lipid agglomerates deposited on thin film aluminum surfaces. Collective protocell structures were observed to be mechanically more stable compared to isolated spherical compartments. We show that the model colonies encapsulate DNA and accommodate non-enzymatic, strand displacement DNA reactions. The membrane envelope is able to disassemble and expose individual daughter protocells, which can migrate and attach via nano-tethers to distant surface locations, while maintaining their encapsulated contents. Some colonies feature 'exo-compartments', which spontaneously extend out of the enveloping bilayer, internalize DNA, and merge again with the superstructure. A continuum elastohydrodynamic theory that we developed reveals that the subcompartment formation must be governed by attractive van der Waals (vdW) interactions between the membrane and surface. The balance between membrane bending and vdW interactions yields a critical length scale of 273 nm, above which the membrane invaginations can form subcompartments. The findings support our hypotheses that in extension of the 'lipid world hypothesis', protocells may have existed in the form of colonies, potentially benefiting from the increased mechanical stability provided by a superstructure.

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Section: Resultsmentioning

confidence: 99%

Colony-like Protocell Superstructures

Spustová

Katke

Villalmanzo

et al. 2021

Preprint

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“…The accompanying decrease in vesicle volume results in a membrane tension causing deformation and vesicle fusion. [36][37][38] A second change is salt concentration, returning to a lower salt concentration, was required for vesicle rupture at the air-water interface. Reduction of the salt concentration decreased the distance between the larger fused vesicles (with larger contact area than the original vesicles) and the monolayer and increased the internal volume of the fused vesicles resulting in vesicle rupture to a planar bilayer.…”

Section: Introductionmentioning

confidence: 99%

Suspended phospholipid bilayers: a new biological membrane mimetic

Ayscough

Skoda

Clifton

et al. 2022

Preprint

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Hypothesis: The attractive interaction between a cationic surfactant monolayer at the air-water interface and vesicles, incorporating anionic lipids, is sufficient to drive the adsorption and deformation of the vesicles. Osmotic rupture of the vesicles produces a continuous lipid bilayer beneath the monolayer. Experimental: Specular neutron reflectivity has been measured from the surface of a purpose-built laminar flow trough, which allows for rapid adsorption of vesicles, the changes in salt concentration required for osmotic rupture of the adsorbed vesicles into a bilayer, and for neutron contrast variation of the sub-phase without disturbing the monolayer. Findings: The neutron reflectivity profiles measured after vesicle addition are consistent with the adsorption and flattening of the vesicles beneath the monolayer. An increase in the buffer salt concentration results in further flattening and fusion of the adsorbed vesicles, which are ruptured by a subsequent decrease in the salt concentration. This process results in a continuous, high coverage, bilayer suspended 11A beneath the monolayer. As the bilayer is not constrained by a solid substrate, this new mimetic is well-suited to studying the structure of lipid bilayers that include transmembrane proteins.

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“…Code and data availability Appropriate documentation and example files to replicate the simula-tion results presented in this work together with all necessary analysis code can be found at the following public repository [72]. Additionally, a maintained version of the code is available on GitHub [73].…”

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confidence: 99%

Self-organisation of mortal filaments: the role of FtsZ treadmilling in bacterial division ring formation

Campos

Whitley

Radler

et al. 2023

Preprint

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Functional protein filaments in the cell commonly treadmill - grow and shrink on opposite ends, driven by energy consumption. Treadmilling causes filaments to seem as if they were moving, even though the individual proteins remain static. Here we investigate the role of treadmilling, implemented as dynamic turnover, in the collective filament self-organisation. On the example of the bacterial FtsZ protein, a highly evolutionary conserved tubulin homologue, we show, in computer simulations and in vitro experiment, that treadmilling drives filament nematic ordering by means of dissolving misaligned filaments. We demonstrate that this ordering via local dissolution allows the system to quickly respond to chemical and geometrical biases in the cell, and is necessary for the formation of the bacterial division ring in live Bacillus subtilis. We finally use simulations to quantitatively explain the characteristic dynamics of FtsZ division ring formation measured in vivo. Beyond FtsZ and cytoskeletal filaments, our study identifies a novel mechanism for nematic ordering via constant birth and death of energy-consuming filaments.

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Modelling the dynamics of vesicle reshaping and scission under osmotic shocks

Cited by 4 publications

References 42 publications

Colony-like Protocell Superstructures

Colony-like Protocell Superstructures

Suspended phospholipid bilayers: a new biological membrane mimetic

Self-organisation of mortal filaments: the role of FtsZ treadmilling in bacterial division ring formation

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