Themed collection Structural and functional asymmetry of plasma membranes

This paper summarizes a series of ideas and/or concepts, most of which were the object of the Faraday Discussion on ‘Structural and functional asymmetry of plasma membranes’.

The asymmetry in membrane lipid composition establishes a preferred direction for fusion. Here, we integrate theory and experiment to demonstrate that fusion initiated from opposite sides of an asymmetric membrane encounters distinct energy barriers.

A model system that mimics the glycocalyx: a lipid bilayer coated with chondroitin sulfate.

We will discuss how sustained nonequilibrium processes operating at the plasma membrane (PM) determine the dynamical organisation (both lateral and transverse) of lipids, their maintenance and control, under physiological conditions.

Using all-atom MD simulations, we show that the biophysical properties of compositionally asymmetric POPC/DOPC bilayers are strongly correlated with the density imbalance between the leaflets.

Asymmetric expansion of the leaflets of lipid-asymmetric vesicles due to the melting gel phases induces interleaflet coupling and/or vesicle budding.

State-of-the-art sum-frequency generation microscopy quantitatively reveals the heterogeneous changes in density, order, and composition from PS-lipid exposure in model membranes.

Asymmetric GUV of phase-separated Lo + Ld in one leaflet, dyed red, inducing domains in the other leaflet of DOPC/chol, dyed green.

We investigate the effect of the melting transition temperature of lipid nanocarriers on the activation efficiency of an immortalized line of T lymphocytes.

We hypothesize that transbilayer asymmetry of PI(4,5)P₂ and other membrane lipids controls the thermodynamic properties of plasma membranes, governing the kinetics of FGF2 membrane translocation into the extracellular space.

Ca²⁺ ions are believed to play a crucial role in enzymatic regulation of lipid membrane asymmetry, yet direct effects of Ca²⁺ on lipid flip-flop are unknown. Present work examines the influence of Ca–lipid interactions on lipid translocation.

We show that phosphatidylserine and phosphatidylethanolamine appear as transient foci on the plasma membrane external leaflet following immune receptor-mediated activation of mast cells.

A model for how loss of asymmetry due to lipid scrambling may change membrane domain formation.

We investigate how well transmembrane domains of single-pass transmembrane proteins predict asymmetric membrane properties across the tree of life.

Rapid shape changes of cells are facilitated by membrane viscosity and higher order geometric terms.

The hemifusion method is applied to the fabrication of asymmetric Giant Unilamellar Vesicles (aGUVs) with phosphatidylinositol-(4,5)-bisphosphate (PI(4,5)P₂) in a physiological ionic strength buffer solution.

Electric double layer, lipid hydration and SH imaging of hydration asymmetry. Fully symmetric bilayer with symmetric hydration (no coherent SH emission), and three ways in which this symmetry can be broken (with coherent SH emission).

We report simulations and analysis of the A_2A adenosine receptor in its fully active state, in two different membrane environments.

We studied the structure and dynamics of asymmetric POPC^out/(POPE/POPG)ⁱⁿ and POPS^out/(POPE/POPG)ⁱⁿ lipid membranes.

We use atomistic simulations of lipid bilayers to generate representative datasets from model membranes in vitro, and examine the sensitivity of various experimental techniques to lipid abundance imbalances in compositionally asymmetric bilayers.

We propose a thermodynamic framework that describes the conditions for coexistence between the two leaflets of an asymmetric ternary lipid membrane comprising a saturated lipid, an unsaturated lipid, and cholesterol.

Complementary charge matching between a protein-induced membrane dipole and a folding OMP leads to optimal folding kinetics and protein stability.

We introduce a new Monte Carlo method to measure the elastic properties of ultra coarse-grained asymmetric membranes.

This work presents a theoretical model describing the interaction of lipid domains in apposed membrane monolayers, originating from differential contact energy, and predict conditions for domain attraction or repulsion.

We elucidate the many faces of membrane tension for biomimetic model membranes such as planar bilayers, nanovesicles, and giant vesicles. In all systems, each of the two leaflet tensions and the bilayer tension ∑ can be positive, zero, or negative.