Lipid droplets store neutral lipids, primarily triacylglycerol and steryl esters. Seipin plays a role in lipid droplet biogenesis and is thought to determine the site of lipid droplet biogenesis and the size of newly formed lipid droplets. Here we show a seipin-independent pathway of lipid droplet biogenesis. In silico and in vitro experiments reveal that retinyl esters have the intrinsic propensity to sequester and nucleate in lipid bilayers. Production of retinyl esters in mammalian and yeast cells that do not normally produce retinyl esters causes the formation of lipid droplets, even in a yeast strain that produces only retinyl esters and no other neutral lipids. Seipin does not determine the size or biogenesis site of lipid droplets composed of only retinyl esters or steryl esters. These findings indicate that the role of seipin in lipid droplet biogenesis depends on the type of neutral lipid stored in forming droplets.

中文翻译：

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视黄酯形成脂滴，独立于三酰甘油和 seipin

脂滴储存中性脂质，主要是三酰甘油和甾醇酯。Seipin 在脂滴生物发生中发挥作用，被认为决定脂滴生物发生的位点和新形成的脂滴的大小。在这里，我们展示了脂滴生物发生的不依赖于 seipin 的途径。计算机和体外实验表明，视黄酯具有在脂质双层中螯合和成核的内在倾向。在通常不产生视黄酯的哺乳动物和酵母细胞中产生视黄酯会导致脂滴的形成，即使在仅产生视黄酯而不产生其他中性脂质的酵母菌株中也是如此。Seipin 无法确定仅由视黄酯或甾醇酯组成的脂滴的大小或生物发生位点。这些发现表明，seipin 在脂滴生物发生中的作用取决于形成液滴中储存的中性脂质的类型。