An ER protein links fat storage on droplets to membrane fat production in the ER

In S. cerevisiae, lipid droplets localize enzymes that sustain their growth and are involved in lipid metabolism transitions.

• Lipid droplets grow in size during the early stationary phase due to the action of enzymes localized on them.
• The enzyme Dga1p transfers from the endoplasmic reticulum to lipid droplets to synthesize triacylglycerol from diacylglycerol.
• In early exponential phase, the protein Ice2p from the endoplasmic reticulum aids in breaking down triacylglycerol for membrane lipid synthesis.
• Ice2p has a part that binds to lipid droplets, which is necessary for efficient utilization of lipid droplet-derived diacylglycerol.
• Ice2p helps eliminate a cycle of synthesis and degradation on lipid droplets, facilitating the movement of Dga1p back to the endoplasmic reticulum.

Simplified