An eukaryotic cell is composed of thousands of different lipid species, which fulfill essential functions, serving as membrane building blocks, signaling molecules and reservoirs of energy. Following their synthesis, lipids need to be sorted to the correct cellular compartment. In our lab, we study how lipids are transferred between compartments via lipid transfer proteins, and how they are stored in lipid droplets. For this, we use different model systems, from the unicellular budding yeast and cultured cell lines to artificial reconstituted systems of proteins and lipids. We combine a variety of approaches (bioinformatics, molecular biology, biochemistry, fluorescent microscopy and biophysical methods) to dissect molecular details of these fundamental cellular processes.

1. Lipid transfer often occurs within membrane contact sites, which are regions of close apposition between organelles. We are particularly interested in the homeostasis of phosphatidylserine, which is synthesized in the endoplasmic reticulum, but is highly enriched in the cytosolic leaflet of the plasma membrane. We study how the yeast PS transfer protein Osh6 cooperates with an ER-PM tether Ist2 to deliver PS to the plasma membrane.
2. Lipid droplets are ubiquitous cellular organelles with a highly variable size that depends on cell type, reaching more than 100 micrometers in mature adipocytes. We study a family of abundant LD proteins, the perilipins, which interact with LDs using amphipathic helices. We are interested in how perilipins contribute to the maintenance of LD size and stability, in particular in adipocytes.