When the little balls of fat that float in our cells grow and accumulate excessively, they can cause a variety of health problems, including obesity, diabetes, and heart disease. But these lipid droplets play a vital role in cells: storing energy as well as the materials needed to build and maintain biological membranes. Tobias Walther wants to understand the molecular mechanisms behind lipid storage in cells.
With colleague Robert Farese, he identified more than 200 genes that regulate lipid storage. He discovered that there are two classes of lipid droplets: small, static droplets and larger droplets that expand as needed. Walther showed how enzymes involved in synthesis of triglycerides (one type of lipid stored in the droplets) locate and engage with the expanding droplets to build new triglycerides.
His team also studies how membrane lipids not stored in droplets are kept in balance inside cells. Ultimately, Walther aims to uncover the biochemical and physical principles that govern lipid balance and storage and to determine how alterations in lipid stores affect physiology and disease.