A conserved family of proteins facilitates nascent lipid droplet budding from the ER.
A conserved family of proteins facilitates nascent lipid droplet budding from the ER.
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DOI：
10.1083/jcb.201505067
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发表时间：
2015-10-26
期刊：
影响因子：
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通讯作者：
Prinz WA
中科院分区：
文献类型：
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作者：
Choudhary V;Ojha N;Golden A;Prinz WA
新生脂滴的可视化显示，它们在ER膜双层内形成透镜状结构，并且FIT蛋白是脂滴向细胞质突出所必需的。脂滴（LDs）存在于所有细胞中，并在脂质代谢中发挥重要作用。LD的新生生物发生在内质网（ER）中，但尚未得到很好的理解。我们使用电子显微镜对LD生物发生的早期阶段进行了成像，发现新生LD在ER膜中形成透镜状结构，提出了这些新生LD在生长时如何从ER出芽的问题。我们发现一个保守的蛋白质家族，脂肪储存诱导跨膜蛋白（FIT），是从ER正确出芽的LD所必需的。酵母和高等真核生物中FIT蛋白的消除或减少导致LDs保留在ER膜中。秀丽隐杆线虫中单个FIT蛋白的缺失是致命的，这表明LD出芽是这种生物体中的一个重要过程。我们的研究结果表明，FIT蛋白是必要的，以促进萌芽的新生LD从ER。
Visualization of nascent lipid droplets reveals that they form lens-like structures inside the ER membrane bilayer and that FIT proteins are necessary for lipid droplet protrusion toward the cytoplasm. Lipid droplets (LDs) are found in all cells and play critical roles in lipid metabolism. De novo LD biogenesis occurs in the endoplasmic reticulum (ER) but is not well understood. We imaged early stages of LD biogenesis using electron microscopy and found that nascent LDs form lens-like structures that are in the ER membrane, raising the question of how these nascent LDs bud from the ER as they grow. We found that a conserved family of proteins, fat storage-inducing transmembrane (FIT) proteins, is required for proper budding of LDs from the ER. Elimination or reduction of FIT proteins in yeast and higher eukaryotes causes LDs to remain in the ER membrane. Deletion of the single FIT protein in Caenorhabditis elegans is lethal, suggesting that LD budding is an essential process in this organism. Our findings indicated that FIT proteins are necessary to promote budding of nascent LDs from the ER.