COPI buds 60-nm lipid droplets from reconstituted water–phospholipid–triacylglyceride interfaces, suggesting a tension clamp function

摘要: Intracellular trafficking between organelles is achieved by coat protein complexes, protomers, that bud vesicles from bilayer membranes. Lipid droplets are protected a monolayer and thus seem unsuitable targets for coatomers. Unexpectedly, complex I (COPI) required lipid droplet targeting of some proteins, suggesting possible direct interaction COPI droplets. Here, we find components can 60-nm triacylglycerol nanodroplets artificial (LD) interfaces. This budding decreases phospholipid packing the decorating mother LD. As result, hydrophobic molecules become more exposed to aqueous environment, increasing LD surface tension. In vivo, this tension increase may prime reactions with neighboring proteins or It provides mechanism fundamentally different transport vesicle formation COPI, likely responsible diverse phenotypes associated depletion subunits.