A bridge to understanding lipid droplet growth

Lipid droplets, storage sites of fatty acids and sterols, expand when excess lipids are converted to triacylglycerols. In this issue of Developmental Cell, Wilfling et al. (2013) show that this expansion relies on relocalization, via membrane bridges, of triacylglycerol-synthesizing enzymes from the ER to a subset of lipid droplets.