Chinese hamster ovary K2 cell lipid droplets appear to be metabolic organelles involved in membrane traffic
Chinese hamster ovary K2 cell lipid droplets appear to be metabolic organelles involved in membrane traffic
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DOI：
10.1074/jbc.m311945200
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发表时间：
2004-01-30
影响因子：
4.8
通讯作者：
Anderson, RGW
中科院分区：
文献类型：
--
作者：
Liu, PS;Ying, YS;Anderson, RGW
动物细胞脂滴中的主要脂类是胆固醇、胆固醇酯和甘油三酯，但这一部分的蛋白质组成在很大程度上是未知的。在这里，我们报告了脂滴的蛋白质组学分析。利用质谱学和免疫印迹相结合的方法，我们从正常培养的中国仓鼠卵巢K2细胞中分离出近40个特异相关蛋白。这些蛋白质分为五类：液滴样脂肪分化相关蛋白的结构分子；参与胆固醇酯和甘油三酯的合成、储存、利用和降解的多种酶；已知参与调节膜交通的多种不同的Rab GTP酶；信号分子，如p50RhoGAP；以及一组不符合任何分类但包括经常在小窝/木筏中发现的蛋白质，如小窝-1和2以及Flotillin-1。从油酸盐存在下生长的细胞中分离出的液滴的蛋白质组基本相同，只是脂肪分化相关蛋白小窝蛋白-1的数量增加，以及一种被认为参与磷脂循环的蛋白质CGI-58。根据蛋白质图谱，脂滴似乎是一个复杂的代谢活性细胞器，直接参与膜运输，并可能参与磷脂循环。我们建议将这种细胞器命名为脂质体。
The principal lipids in animal cell lipid droplets are cholesterol, cholesterol ester, and triglyceride, but the protein composition of this compartment is largely unknown. Here we report on the proteomic analysis of lipid droplets. Using a combination of mass spectrometry and immunoblotting, we identify nearly 40 specifically associated proteins in droplets isolated from Chinese hamster ovary K2 cells grown in normal medium. The proteins fall in to five groups: structural molecules of the droplet-like adipose differentiation-related protein; multiple enzymes involved in the synthesis, storage, utilization, and degradation of cholesterol esters and triglycerides; multiple, different Rab GTPases known to be involved in regulating membrane traffic; signaling molecules such as p50RhoGAP; and a group of proteins that do not fit any classification but include proteins often found in caveolae/rafts such as caveolin-1 and 2 and flotillin-1. The proteome of droplets isolated from cells grown in the presence of oleate is largely the same except for an increase in the amount of adipose differentiation-related protein, caveolin-1, and a protein thought to be involved in phospholipid recycling called CGI-58. Based on the protein profile, the lipid droplet appears to be a complex, metabolically active organelle that is directly involved in membrane traffic and possibly phospholipid recycling. We propose the name adiposome for this organelle.