High confidence proteomic analysis of yeast LDs identifies additional droplet proteins and reveals connections to dolichol synthesis and sterol acetylation.
High confidence proteomic analysis of yeast LDs identifies additional droplet proteins and reveals connections to dolichol synthesis and sterol acetylation.
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DOI：
10.1194/jlr.m050229
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发表时间：
2014-07
影响因子：
6.5
通讯作者：
Farese RV Jr
中科院分区：
文献类型：
--
作者：
Currie E;Guo X;Christiano R;Chitraju C;Kory N;Harrison K;Haas J;Walther TC;Farese RV Jr
准确的蛋白质清单对于理解细胞器的功能至关重要。脂滴（LD）是一种普遍存在的细胞内细胞器，具有脂质储存和代谢的主要功能。ld与其他细胞器的不同之处在于，它们被表面单层包围，呈现出蛋白质靶向ld的独特特征。通过蛋白质组学分析，在纯化的LD中发现了多种功能的蛋白质。虽然这些研究变得越来越敏感，但通常不清楚哪些已鉴定的蛋白质是ld特异性的。在这里，我们使用蛋白相关分析鉴定了35个蛋白，这些蛋白特异富集于酿酒酵母的LD部分。在这些候选蛋白中，30个荧光团标记的蛋白通过显微镜定位到LD，包括6个蛋白，其中几个与疾病相关的人类同源物，我们新鉴定为LD蛋白（Cab5, Rer2, Say1, Tsc10， YKL047W和YPR147C）。其中两种蛋白质，Say1（一种甾醇去乙酰化酶）和Rer2（一种顺式异戊二醇转移酶）分别参与甾醇和聚戊二醇代谢，我们发现它们的活性存在于LD馏分中。我们的研究结果提供了一个高度特异性的酵母LD蛋白列表，并揭示了绝大多数这些蛋白参与脂质代谢。
Accurate protein inventories are essential for understanding an organelle’s functions. The lipid droplet (LD) is a ubiquitous intracellular organelle with major functions in lipid storage and metabolism. LDs differ from other organelles because they are bounded by a surface monolayer, presenting unique features for protein targeting to LDs. Many proteins of varied functions have been found in purified LD fractions by proteomics. While these studies have become increasingly sensitive, it is often unclear which of the identified proteins are specific to LDs. Here we used protein correlation profiling to identify 35 proteins that specifically enrich with LD fractions of Saccharomyces cerevisiae. Of these candidates, 30 fluorophore-tagged proteins localize to LDs by microscopy, including six proteins, several with human orthologs linked to diseases, which we newly identify as LD proteins (Cab5, Rer2, Say1, Tsc10, YKL047W, and YPR147C). Two of these proteins, Say1, a sterol deacetylase, and Rer2, a cis-isoprenyl transferase, are enzymes involved in sterol and polyprenol metabolism, respectively, and we show their activities are present in LD fractions. Our results provide a highly specific list of yeast LD proteins and reveal that the vast majority of these proteins are involved in lipid metabolism.