The lack of the C-terminal domain of adipose triglyceride lipase causes neutral lipid storage disease through impaired interactions with lipid droplets
The lack of the C-terminal domain of adipose triglyceride lipase causes neutral lipid storage disease through impaired interactions with lipid droplets
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DOI：
10.1210/jc.2007-2247
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发表时间：
2008-07-01
影响因子：
5.8
通讯作者：
Takayanagi, Ryoichi
中科院分区：
文献类型：
--
作者：
Kobayashi, Kunihisa;Inoguchi, Toyoshi;Takayanagi, Ryoichi
背景：脂滴中甘油三酯的合成、储存和降解的分子机制尚需阐明。目的：报道携带一种新的脂肪甘油三酯脂肪酶(ATGL)突变的中性脂肪沉积性疾病伴肌病(NLSDM)的同胞，并确定ATGL的C末端是否在与LD的相互作用中发挥作用。设计和患者：皮肤成纤维细胞和外周血白细胞来自NLSDM患者。用成纤维细胞和COS7细胞进行体外实验。主要观察指标：用基因转染法检测不同重组ATGL蛋白对脂肪酶活性和脂肪含量的影响。结果：ATGL基因的直接测序显示，患者为4个碱基缺失的纯合子，导致过早终止密码子，导致蛋白C末端包括疏水结构域的缺失。NLSDM成纤维细胞在LDS边缘过表达对照ATGL，细胞内脂质积聚明显减少。相反，尽管有LDS存在，NLSDM ATGL仍均匀地定位于细胞质中，而尽管其脂肪酶活性相似，但对LD的降解几乎没有影响。一系列没有完整疏水结构域的C末端截短的ATGL不能在LDS周围定位和降解。结论：包括ATGL疏水区域在内的结构域对于LDS的结合是必不可少的。
Context: The molecular mechanisms by which triglycerides in lipid droplets (LDs) are synthesized, stored, and degraded need to be elucidated.Objective: The objectives were to report siblings with neutral lipid storage disease with myopathy (NLSDM) with a novel mutation of adipose triglyceride lipase (ATGL) and determine whether the C-terminal part of ATGL containing the hydrophobic region plays a role in the interaction with LDs.Design and Patients: Skin fibroblasts and peripheral blood leukocytes were obtained from NLSDM patients. In vitro experiments were performed with fibroblasts and COS7 cells.Main Outcome Measures: Transfection studies were used to assess the effects of various recombinant ATGL proteins on lipase activities and lipid contents. Fluorescence microscopy were used for determination of intracellular distribution of ATGL proteins.Results: The direct sequence of ATGL cDNA reveals that a patient is a homozygote for the 4-bp deletion, leading to a premature stop codon and causes the lack of the C terminus of the protein including the hydrophobic domain. Overexpressed control ATGL in NLSDM fibroblasts was found around the rims of LDs and caused significantly reduced cellular lipid accumulation. In contrast, NLSDM ATGL was homogeneously located in the cytoplasm despite the presence of LDs and had almost no effect on LD degradation despite its similar lipase activity. A series of C-terminal truncated ATGLs without the intact hydrophobic domain failed to localize around and degrade LDs.Conclusions: These findings indicate that the domain including the hydrophobic region of ATGL was essential for association with LDs.