Project A13

Lipid Storage Organelles in Formation of Polarized Cellular Interfaces during Cell Division and Cell Fusion

Formation of polarized cellular interfaces is a key process in cell division and fusion. While the molecular mechanisms underlying cell polarization have been studied in detail, it is currently not fully understood how local remodeling of the plasma membrane required for fusion and division of cells is mediated. Lipid droplets are ubiquitous cellular organelles that fulfill central functions in the storage and metabolism of lipids. In yeast, a fraction of lipid droplets localize to polarity sites, but how and why this happens is unknown. We hypothesize that lipid droplets are involved in remodeling of cellular interfaces by providing specific lipid building blocks. Using genome-wide microscopy-based screening, we have recently identified a mutant that displays an enhanced polarization of the lipid droplet pool, resulting in lipid droplet accumulation in emerging daughter cells during cell division, and in mating protrusions during cell fusion. In this CRC, we will use our findings as an entry point into investigating lipid droplet polarization, aiming at answering two key questions: How is lipid droplet polarization achieved on a molecular level? And how do lipid droplets affect formation of polarized plasma membrane interfaces during cell division and fusion?