Liposomal adhesion via electrostatic interactions and osmotic deflation increase membrane tension and lipid diffusion coefficient

Soft Matter ◽  
2020 ◽  
Vol 16 (18) ◽  
pp. 4549-4554 ◽  
Author(s):  
Atsushi Oda ◽  
Chiho Watanabe ◽  
Natsumi Aoki ◽  
Miho Yanagisawa
Keyword(s):  
Diffusion Coefficient ◽  
Electrostatic Interactions ◽  
Membrane Tension ◽  
Lipid Diffusion ◽  
Osmotic Contraction

Liposome–liposome adhesion by electrostatic interactions and osmotic contraction increase membrane tension and the lipid diffusion coefficient compared to isolated liposomes.

scholarly journals Lateral diffusion and retrograde movements of individual cell surface components on single motile cells observed with Nanovid microscopy.

1991 ◽  
Vol 112 (1) ◽  
pp. 111-124 ◽  
Author(s):  
M de Brabander ◽  
R Nuydens ◽  
A Ishihara ◽  
B Holifield ◽  
K Jacobson ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Cell Surface ◽  
Electrostatic Interactions ◽  
Individual Cell ◽  
Lateral Diffusion ◽  
Uniform Motion ◽  
Specific Cell ◽  
3T3 Fibroblasts ◽  
Motile Cells ◽  
Perinuclear Cytoplasm

A recently introduced extension of video-enhanced light microscopy, called Nanovid microscopy, documents the dynamic reorganization of individual cell surface components on living cells. 40-microns colloidal gold probes coupled to different types of poly-L-lysine label negative cell surface components of PTK2 cells. Evidence is provided that they bind to negative sialic acid residues of glycoproteins, probably through nonspecific electrostatic interactions. The gold probes, coupled to short poly-L-lysine molecules (4 kD) displayed Brownian motion, with a diffusion coefficient in the range 0.1-0.2 micron2/s. A diffusion coefficient in the 0.1 micron2/s range was also observed with 40-nm gold probes coupled to an antibody against the lipid-linked Thy-1 antigen on 3T3 fibroblasts. Diffusion of these probes is largely confined to apparent microdomains of 1-2 microns in size. On the other hand, the gold probes, coupled to long poly-L-lysine molecules (240 kD) molecules and bound to the leading lamella, were driven rearward, toward the boundary between lamelloplasm and perinuclear cytoplasm at a velocity of 0.5-1 micron/min by a directed ATP-dependent mechanism. This uniform motion was inhibited by cytochalasin, suggesting actin microfilament involvement. A similar behavior on MO cells was observed when the antibody-labeled gold served as a marker for the PGP-1 (GP-80) antigen. These results show that Nanovid microscopy, offering the possibility to observe the motion of individual specific cell surface components, provides a new and powerful tool to study the dynamic reorganization of the cell membrane during locomotion and in other biological contexts as well.

scholarly journals Membrane insertion of Cavin1 facilitates caveolae assembly

2021 ◽  
Author(s):  
Kang-cheng Liu ◽  
Hudson Pace ◽  
Elin Larsson ◽  
Shakhawath Hossain ◽  
Aleksei Kabedev ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Living Cells ◽  
Membrane Curvature ◽  
Small Cell ◽  
Signaling Cascades ◽  
Membrane Insertion ◽  
Membrane Tension ◽  
Membrane Interface ◽  
Biophysical Techniques ◽  
Helical Region

Caveolae are small cell surface invaginations, important for control of membrane tension, signaling cascades and lipid sorting. Their formation is coupled to the lipid-dependent oligomerization of the proteins Caveolin1 and Cavin1, which are essential for membrane curvature generation. Yet, the mechanistic understanding of how Cavin1 assembles at the membrane interface is lacking. Here, we used model membranes combined with biophysical techniques to show that Cavin1 inserts into membranes. We found that the helical region 1 (HR1) initiated membrane binding via electrostatic interactions, which is further enforced by partial helical insertion in a PI(4,5)P2-dependent process mediated by the disordered region 1 (DR1). In agreement with this, the DR1 was found important for the co-assembly of Cavin1 with Caveolin1 in living cells. We propose that DR1 and HR1 of Cavin1 constitute a novel membrane interacting unit facilitating dynamic rounds of assembly and disassembly of Cavin1 at the membrane.

scholarly journals Membrane Constriction by ESCRT-III Proteins Induces Structural Lipid Bilayer Asymmetries

2021 ◽  
Author(s):  
Frank Russell Moss ◽  
James Lincoff ◽  
Maxwell Tucker ◽  
Arshad Mohammed ◽  
Michael Grabe ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Protein Interactions ◽  
Electrostatic Interactions ◽  
Membrane Surface ◽  
Spontaneous Curvature ◽  
Membrane Mechanics ◽  
Vesicular Traffic ◽  
Outer Leaflet ◽  
Lipid Diffusion ◽  
Lipid Protein Interactions

Cells utilize molecular machines to form and remodel their membrane-defined compartments' compositions, shapes, and connections. The regulated activity of these membrane remodeling machines drives processes like vesicular traffic and organelle homeostasis. Although molecular patterning within membranes is essential to cellular life, characterizing the composition and structure of realistic biological membranes on the molecular length scale remains a challenge, particularly during membrane shape transformations. Here, we employed an ESCRT-III protein coating model system to investigate how membrane-binding proteins bind to and alter the structural patterns within lipid bilayers. We observe leaflet-level and localized lipid structures within a constricted and thinned membrane nanotube. To map the fine structure of these membranes, we compared simulated bilayer nanotubes with experimental cryo-EM reconstructions of native membranes and membranes containing halogenated lipid analogs. Halogenated lipids scatter electrons more strongly, and analysis of their surplus scattering enabled us to estimate the concentrations of lipids within each leaflet and to estimate lipid shape and sorting changes induced by high curvature and lipid-protein interactions. Specifically, we found that cholesterol enriched within the inner leaflet due to its spontaneous curvature, while acidic lipids enriched in the outer leaflet due to electrostatic interactions with the protein coat. The docosahexaenoyl (DHA) polyunsaturated chain-containing lipid SDPC enriched strongly at membrane-protein contact sites. Simulations and imaging of brominated SDPC showed how a pair of phenylalanine residues opens a hydrophobic defect in the outer leaflet and how DHA tails stabilize the defect and "snorkel" up to the membrane surface to interact with these side chains. This highly curved nanotube differs markedly from protein-free, flat bilayers in leaflet thickness, lipid diffusion, and other structural asymmetries with implications for our understanding of membrane mechanics.

scholarly journals In vivo lipid diffusion coefficient measurements in rat bone marrow

2009 ◽  
Vol 27 (6) ◽  
pp. 859-864 ◽  
Author(s):  
Zaid Q. Ababneh ◽  
Helene Beloeil ◽  
Charles B. Berde ◽  
Anas M. Ababneh ◽  
Stephan E. Maier ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Diffusion Coefficient ◽  
Lipid Diffusion ◽  
Rat Bone

scholarly journals Physiological Membrane Tension Causes An Increase In Lipid Diffusion: A Single Molecule Fluorescence Study

2009 ◽  
Vol 96 (3) ◽  
pp. 197a-198a ◽  
Author(s):  
Hari S. Muddana ◽  
Ramachandra Rao Gullapalli ◽  
Tristan Tabouillot ◽  
Peter J. Butler
Keyword(s):  
Single Molecule ◽  
Membrane Tension ◽  
Single Molecule Fluorescence ◽  
Fluorescence Study ◽  
Lipid Diffusion

Template mediated crystal engineering

1994 ◽  
Vol 52 ◽  
pp. 480-481
Author(s):  
Brigid R. Heywood ◽  
S. Champ
Keyword(s):  
Crystal Engineering ◽  
Electrostatic Interactions ◽  
Alkyl Chain ◽  
Crystallographic Axis ◽  
Two Dimensional ◽  
Engineering Process ◽  
Solution Interface ◽  
Extensive Program ◽  
Geometric Homology ◽  
Long Alkyl Chain

Recent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain surfactant is cast on the crystallisation media a monodispersied population of crystals forms exclusively at the monolayer/solution interface. Each crystal is aligned with a specific crystallographic axis perpendicular to the plane of the monolayer suggesting that nucleation is facilitated by recognition events between the nascent inorganic solid and the organic template.For example, monolayers of the long alkyl chain surfactant, stearic acid will promote the oriented nucleation of the calcium carbonate polymorph, calcite, on the (100) face, whereas compressed monolayers of n-eicosyl sulphate will induce calcite nucleation on the (001) face, (Figure 1 & 2). An extensive program of research has confirmed the general principle that molecular recognition events at the interface (including electrostatic interactions, geometric homology, stereochemical complementarity) can be used to promote the crystal engineering process.

Brief-Measurements of Vapor Diffusion Coefficient

1954 ◽  
Vol 46 (11) ◽  
pp. 47-49 ◽  
Author(s):  
C.Y. Lee ◽  
C.R. Wilke
Keyword(s):  
Diffusion Coefficient ◽  
Vapor Diffusion
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