AC Field Controlled Formation of Giant Fluctuating Vesicles and Bending Elasticity Measurements

Angelova, Maria; Soléau, S.; Méléard, Philippe; Faucon, Jean‐François; Bothorel, P.

doi:10.1007/978-3-642-84763-9_35

Cited by 18 publications

(8 citation statements)

References 13 publications

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“…For micropipet experiments, vesicles were prepared by the electroswelling method . Mixtures of DPPC with the sterol (mixing ratio 6:4) in organic solution (chloroform) were spread on glass slides coated with indium tin oxide (ITO) and dried under vacuum for 2 h. Two slides coated with the same mixture were arranged at a distance of ca.…”

Section: Methodsmentioning

confidence: 99%

The Effect of Cholesterol, Lanosterol, and Ergosterol on Lecithin Bilayer Mechanical Properties at Molecular and Microscopic Dimensions: A Solid-State NMR and Micropipet Study

et al. 2002

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Lecithin (DPPC) membranes doped with high concentrations (40 mol %) of three biologically relevant sterols (cholesterol, lanosterol, and ergosterol) were studied by spectroscopic and force measurements. Micropipet aspiration measurements of giant unilamellar vesicles provided the membrane area expansion modulus K on the microscopic scale while deuterium NMR experiments gave parameters such as the line shape, transverse relaxation, and molecular order, which are all based on a molecular scale at a given time resolution. Micropipet experiments at 10°C gave K values for the three samples with ergosterol > cholesterol > lanosterol. From the NMR we obtained the highest CH2-segmental molecular order and longest transverse relaxation time for cholesterol and the opposite for ergosterol. The lanosterol NMR parameters were found to be between those of the other two sterols but were closer to those of cholesterol. The extent of deformation of the sterol-doped vesicles in the magnetic field of the NMR magnet was lanosterol > cholesterol > ergosterol. The results suggest that membrane micromechanic properties are manifest in solid-state NMR parameters and suggest that high K values at the microscopic scale correspond to high molecular order and long transverse relaxation times at the molecular scale. Furthermore, the extent of magnetic field orientation of vesicles measured by NMR correlated well with K determined by micropipet aspiration. The results may help to appreciate why cholesterol has gained a dominant role over the other sterols in the course of cellular evolution.

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Section: Methodsmentioning

confidence: 99%

The Effect of Cholesterol, Lanosterol, and Ergosterol on Lecithin Bilayer Mechanical Properties at Molecular and Microscopic Dimensions: A Solid-State NMR and Micropipet Study

et al. 2002

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“…All GUVs were supplemented with 1% Rhodamine-PE. GUVs were made by electro-formation as described (Angelova et al, 1992). SUVs were made as described previously (Baskaran et al, 2012).…”

Section: Liposome Preparation and Imagingmentioning

confidence: 99%

Membrane scission driven by the PROPPIN Atg18

et al. 2017

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Sorting, transport, and autophagic degradation of proteins in endosomes and lysosomes, as well as the division of these organelles, depend on scission of membrane-bound tubulo-vesicular carriers. How scission occurs is poorly understood, but family proteins bind these membranes. Here, we show that the yeast PROPPIN Atg18 carries membrane scission activity. Purified Atg18 drives tubulation and scission of giant unilamellar vesicles. Upon membrane contact, Atg18 folds its unstructured CD loop into an amphipathic α-helix that inserts into the bilayer. This allows the protein to engage its two lipid binding sites for PI3P and PI(3,5)P PI(3,5)P induces Atg18 oligomerization, which should concentrate lipid-inserted α-helices in the outer membrane leaflet and drive membrane tubulation and scission. The scission activity of Atg18 is compatible with its known roles in endo-lysosomal protein trafficking, autophagosome biogenesis, and vacuole fission. Key features required for membrane tubulation and scission by Atg18 are shared by other PROPPINs, suggesting that membrane scission may be a generic function of this protein family.

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“…Both in-plane and out-of-plane measurements show clear evidence of the viscoelastic nature of the composite membranes. Our in vitro model consists of a thin shell of actin filaments polymerized and reticulated on the outside of giant unilamellar vesicles (ϳ20 mm diameter) grown by electroformation [8]. They consist of a mixture of 95% of DOPC and 5% of DOPE-B which has a biotin group attached to its polar head [9].…”

mentioning

confidence: 99%

Microrheology of Biopolymer-Membrane Complexes

et al. 2000

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We create tailored microstructures, consisting of complexes of lipid membranes with self-assembled biopolymer shells, to study the fundamental properties and interactions of these basic components of living cells. We measure the mechanical response of these artificial structures at the micrometer scale, using optical tweezers and single-particle tracking. These systems exhibit rich dynamics that illustrate the viscoelastic character of the quasi-two-dimensional biopolymer network. We present a theoretical model relating the rheological properties of these membranes to the observed dynamics.

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AC Field Controlled Formation of Giant Fluctuating Vesicles and Bending Elasticity Measurements

Cited by 18 publications

References 13 publications

The Effect of Cholesterol, Lanosterol, and Ergosterol on Lecithin Bilayer Mechanical Properties at Molecular and Microscopic Dimensions: A Solid-State NMR and Micropipet Study

The Effect of Cholesterol, Lanosterol, and Ergosterol on Lecithin Bilayer Mechanical Properties at Molecular and Microscopic Dimensions: A Solid-State NMR and Micropipet Study

Membrane scission driven by the PROPPIN Atg18

Microrheology of Biopolymer-Membrane Complexes

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