Proteins under new management: lipid droplets deliver.

Lipid droplets are ubiquitous organelles that store neutral lipids and have crucial roles in lipid metabolism. Recent studies have uncovered many examples of lipid droplets recruiting proteins from other cellular compartments, in a cell type-specific and regulated manner. Some droplet-recruited proteins are destined for destruction, whereas others are released and reused when conditions change. Droplets might therefore have a general role in managing the availability of proteins, and they have been proposed to serve as generic sites of protein sequestration. The implications of this emerging role of lipid droplets include regulated inactivation of proteins, prevention of toxic protein aggregates and localized delivery of signaling molecules.