Université de Fribourg

Local accumulation of diacylglycerol alters membrane properties nonlinearly due to its transbilayer activity

Campomanes, Pablo ; Zoni, Valeria ; Vanni, Stefano

In: Communications Chemistry, 2019, vol. 2, no. 1, p. 72

Diacylglycerols (DAGs) are bioactive lipids that are ubiquitously present at low concentrations in cellular membranes. Upon the activation of lipid remodeling enzymes such as phospholipase C and phosphatidic acid phosphatase, DAG concentration increases, leading to a disruption of the lamellar phase of lipid membranes. To investigate the structural origin of these phenomena, here we develop ...

Université de Fribourg

An atomistic look into bio-inspired nanoparticles and their molecular interactions with cells

Petretto, Emanuele ; Campomanes, Pablo ; Stellacci, Francesco ; Rothen-Rutishauser, Barbara ; Petri-Fink, Alke ; Vanni, Stefano

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 78–80

Nanoparticles (NPs) have sizes that approach those of pathogens and they can interact with the membranes of eukaryotic cells in an analogous fashion. Typically, NPs are taken up by the cell via the plasma membrane by receptor-mediated processes and subsequently interact with various endomembranes. Unlike pathogens, however, NPs lack the remarkable specificity gained during the evolutionary...

Université de Fribourg

Templated assembly of pore-forming peptides in lipid membranes

Fennouri, Aziz ; List, Jonathan ; Dupasquier, Jessica ; Haeni, Laetitia ; Vanni, Stefano ; Rothen-Rutishauser, Barbara ; Mayer, Michael

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 59–62

Pore-forming peptides are of interest due to their antimicrobial activity and ability to form gateways through lipid membranes. Chemical modification of these peptides makes it possible to arrange several peptide monomers into well-defined pore-forming structures using various templating strategies. These templated super-structures can exert antimicrobial activity at significantly lower total...

Université de Fribourg

Packmem: a versatile tool to compute and visualize interfacial packing defects in lipid bilayers

Gautier, Romain ; Bacle, Amélie ; Tiberti, Marion L. ; Fuchs, Patrick F. ; Vanni, Stefano ; Antonny, Bruno

In: Biophysical Journal, 2018, vol. 115, no. 3, p. 436–444

The analysis of the structural organization of lipid bilayers is generally performed across the direction normal to the bilayer/water interface, whereas the surface properties of the bilayer at the interface with water are often neglected. Here, we present PackMem, a bioinformatic tool that performs a topographic analysis of the bilayer surface from various molecular dynamics simulations....

Université de Fribourg

Toward chemically resolved computer simulations of dynamics and remodeling of biological membranes

Soares, Thereza A. ; Vanni, Stefano ; Milano, Giuseppe ; Cascella, and Michele

In: The Journal of Physical Chemistry Letters, 2017, vol. 8, no. 15, p. 3586–3594

Cellular membranes are fundamental constituents of living organisms. Apart from defining the boundaries of the cells, they are involved in a wide range of biological functions, associated with both their structural and the dynamical properties. Biomembranes can undergo large-scale transformations when subject to specific environmental changes, including gel–liquid phase transitions, change...

Université de Fribourg

ER membrane phospholipids and surface tension control cellular lipid droplet formation

M'barek, Kalthoum Ben ; Ajjaji, Dalila ; Chorlay, Aymeric ; Vanni, Stefano ; Forêt, Lionel ; Thiam, Abdou Rachid

In: Developmental Cell, 2017, vol. 41, no. 6, p. 591–604.e7

Cells convert excess energy into neutral lipids that are made in the endoplasmic reticulum (ER) bilayer. The lipids are then packaged into spherical or budded lipid droplets (LDs) covered by a phospholipid monolayer containing proteins. LDs play a key role in cellular energy metabolism and homeostasis. A key unanswered question in the life of LDs is how they bud off from the ER. Here, we...