Université de Fribourg

Seipin accumulates and traps diacylglycerols and triglycerides in its ring-like structure

Zoni, Valeria ; Khaddaj, Rasha ; Lukmantara, Ivan ; Shinoda, Wataru ; Hongyuan, Yang ; Schneiter, Roger ; Vanni, Stefano

In: Proceedings of the National Academy of Sciences, 2021, vol. 118, no. 10, p. e2017205118

Lipid droplets (LDs) are intracellular organelles responsible for lipid storage, and they emerge from the endoplasmic reticulum (ER) upon the accumulation of neutral lipids, mostly triglycerides (TG), between the two leaflets of the ER membrane. LD biogenesis takes place at ER sites that are marked by the protein seipin, which subsequently recruits additional proteins to catalyze LD formation....

Université de Fribourg

Estimating the accuracy of the MARTINI model towards the investigation of Peripheral Protein-Membrane Interactions

Srinivasan, Sriraksha ; Zoni, Valeria ; Vanni, Stefano

In: Faraday Discussions, 2020, p. -

Peripheral membrane proteins play a major role in numerous biological processes by transiently associating with cellular membranes, often with extreme membrane specificity. Because of the short-lived nature of these interactions, molecular dynamics (MD) simulations have emerged as an appealing tool to characterize at the structural level the molecular details of the protein-membrane...

Université de Fribourg

Conserved functions of ether lipids and sphingolipids in the early secretory pathway

Jiménez-Rojo, Noemi ; Leonetti, Manuel D. ; Zoni, Valeria ; Colom, Adai ; Feng, Suihan ; Iyengar, Namrata R. ; Matile, Stefan ; Roux, Aurélien ; Vanni, Stefano ; Weissman, Jonathan S. ; Riezman, Howard

In: Current Biology, 2020, vol. 30, no. 19, p. 3775-3787.e7

Sphingolipids play important roles in physiology and cell biology, but a systematic examination of their functions is lacking. We performed a genome-wide CRISPRi screen in sphingolipid-depleted human cells and identified hypersensitive mutants in genes of membrane trafficking and lipid biosynthesis, including ether lipid synthesis. Systematic lipidomic analysis showed a coordinate regulation...

Université de Fribourg

Accurate estimation of membrane capacitance from atomistic molecular dynamics simulations of zwitterionic lipid bilayers

Ardham, Vikram Reddy ; Zoni, Valeria ; Adamowicz, Sylvain ; Campomanes, Pablo ; Vanni, Stefano

In: The Journal of Physical Chemistry B, 2020, vol. 124, no. 38, p. 8278–8286

Lipid membranes are indispensable to life, and they regulate countless cellular processes. To investigate the properties of membranes under controlled conditions, numerous reconstitution methods have been developed over the last few decades. Several of these methods result in the formation of lipid bilayers containing residual hydrophobic molecules between the two monolayers. These...

Université de Fribourg

How do ethanolamine plasmalogens contribute to order and structure of neurological membranes?

West, Ana ; Zoni, Valeria ; Teague, Walter E. ; Leonard, Alison N. ; Vanni, Stefano ; Gawrisch, Klaus ; Tristram-Nagle, Stephanie ; Sachs, Jonathan N. ; Klauda, Jeffery B.

In: The Journal of Physical Chemistry B, 2020, vol. 124, no. 5, p. 828–839

Ethanolamine plasmalogen (EtnPLA) is a conical-shaped ether lipid and an essential component of neurological membranes. Low stability against oxidation limits its study in experiments. The concentration of EtnPLA in the bilayer varies depending on cell type and disease progression. Here we report on mixed bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-(1Z-...

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 ...