The seipin complex Fld1/Ldb16 stabilizes ER-lipid droplet contact sites.
The seipin complex Fld1/Ldb16 stabilizes ER-lipid droplet contact sites.
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DOI：
10.1083/jcb.201502070
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发表时间：
2015-11-23
期刊：
影响因子：
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通讯作者：
Carvalho P
中科院分区：
文献类型：
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作者：
Grippa A;Buxó L;Mora G;Funaya C;Idrissi FZ;Mancuso F;Gomez R;Muntanyà J;Sabidó E;Carvalho P
Seipin复合物组分Fld 1和Ldb 16中的突变导致脂滴身份的丧失和磷脂包装缺陷，揭示了该复合物在ER-脂滴接触位点的稳定中的作用。脂滴是一种由磷脂单层和一组脂滴特异性蛋白质包围的中性脂质核心组成的储存细胞器。大多数LD组分在内质网（ER）中合成，内质网是一种通常与LD物理连接的细胞器。LD身份是如何建立的，同时保持与ER的生化和物理联系尚不清楚。在这里，我们表明，酵母seipin Fld 1，在复杂的ER膜蛋白Ldb 16，防止平衡的ER和LD表面成分通过稳定的两个细胞器之间的接触位点。在缺乏Fld 1/Ldb 16复合物的情况下，LD的组装导致磷脂包装缺陷，从而导致脂质结合蛋白和异常LD的异常分布。我们建议Fld 1/Ldb 16复合物通过在ER-LD接触位点充当扩散屏障来促进LD身份的建立。
Mutations in the seipin complex components Fld1 and Ldb16 result in the loss of lipid droplet identity and phospholipid packing defects, revealing a role of this complex in the stabilization of ER–lipid droplet contact sites. Lipid droplets (LDs) are storage organelles consisting of a neutral lipid core surrounded by a phospholipid monolayer and a set of LD-specific proteins. Most LD components are synthesized in the endoplasmic reticulum (ER), an organelle that is often physically connected with LDs. How LD identity is established while maintaining biochemical and physical connections with the ER is not known. Here, we show that the yeast seipin Fld1, in complex with the ER membrane protein Ldb16, prevents equilibration of ER and LD surface components by stabilizing the contact sites between the two organelles. In the absence of the Fld1/Ldb16 complex, assembly of LDs results in phospholipid packing defects leading to aberrant distribution of lipid-binding proteins and abnormal LDs. We propose that the Fld1/Ldb16 complex facilitates the establishment of LD identity by acting as a diffusion barrier at the ER–LD contact sites.