Transport and retention mechanisms govern lipid droplet inheritance in saccharomyces cerevisiae

Abstract

Lipid droplets are ubiquitous cellular structures involved in energy homeostasis and metabolism that have long been considered as simple inert deposits of lipid. Here, we show that lipid droplets are bona fide organelles that are actively partitioned between mother cell and daughter cell in Saccharomyces cerevisiae. Video microscopy revealed that a subset of lipid droplets moves from mother cell to bud in an ordered, vectorial process, while the remaining lipid droplets are retained by the mother cell. Bud-directed movement of lipid droplets is mediated by the molecular motor Myo2p, while retention of lipid droplets occurs at the perinuclear endoplasmic reticulum. Lipid droplets are thus apportioned between mother cell and daughter cell at cell division rather than being made anew. Lipid droplets are ubiquitous organelles involved in lipid metabolism and energy homeostasis. Here we show that lipid droplets are actively partitioned between mother cell and daughter cell in baker's yeast, Saccharomyces cerevisiae. Transport of lipid droplets occurs along actin cables and is dependent on the molecular motor, Myo2p. We also show that lipid droplets maintain their ER association at all times and carry ER elements with them to the bud.