| Lipid droplets (LDs) are depots of neutral lipids that exist in virtually all cells, including bacteria, yeasts, plants and higher mammals. Despite their prevalence, LDs have often been regarded simply as passive fat depots, where excess lipids are stored as esters. However, in recent years it has become clear that LDs are highly dynamic organelles with many different functions, not only in storing energy, but also in the regulation of cholesterol homeostasis, in the biosynthesis of membrane lipids, steroid hormones and eicosanoids. My doctoral research focused on two aspects of the biology of the lipid droplets: (a) active transport of droplets, and (b) protein sequestration, its regulation, and function. In many systems, lipid droplets move in a bi-directional manner along microtubules, powered by molecular motors. Work in the past established many similarities between lipid droplet motion and other bi-directionally moving cargos, so understanding regulation of droplets' motion should increase our understanding of other bi-directionally moving cargos. Clarifying control of lipid droplet motion is also of interest because recent work suggests a link between droplet motion and metabolism. The lipid droplet transport in Drosophila embryos at early stages of development is a well established model system to study molecular motor-based transport, allowing a unique combination of biophysical, biochemical and genetic approaches to investigate microtubule-based transport in vivo. I applied biochemical/proteomic approaches to deepen our understanding of droplet motion, and also to investigate the protein sequestration potential of the lipid droplets with implications for the innate immune response. |
