Role of insulin action and cell size on protein expression patterns in adipocytes
Role of insulin action and cell size on protein expression patterns in adipocytes
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DOI：
10.1074/jbc.m404570200
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发表时间：
2004-07-23
影响因子：
4.8
通讯作者：
Kahn, CR
中科院分区：
文献类型：
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作者：
Blüher, M;Wilson-Fritch, L;Kahn, CR
脂肪特异性胰岛素受体敲除 (FIRKO) 的小鼠表现出白色脂肪组织极化为两种细胞群，一种是小细胞（直径 < 50 μm），一种是大细胞（直径 > 100 μm），同时伴随着胰岛素刺激的葡萄糖摄取、甘油三酯合成和脂肪分解的变化。为了表征脂肪细胞的这些亚类，我们使用了蛋白质组学方法，其中将来自 FIRKO 和对照 (IR lox/lox) 小鼠的分离脂肪细胞按大小分离，分成细胞质和膜亚组分，并通过蔗糖梯度、SDS-PAGE 和质谱法进行分析。脂质和能量代谢关键步骤中蛋白质表达的总共 27 种变化可以被定义，这些变化受到脂肪细胞大小、受损的胰岛素信号传导或两者的协调调节。波形蛋白、含 EH 结构域的蛋白 2、延伸因子 2、葡萄糖调节蛋白 78、转酮醇酶和琥珀酰辅酶 A 转移酶等 9 种蛋白主要受胰岛素信号传导存在与否的影响，而包括肌球蛋白非肌肉形式 A、膜联蛋白 2、膜联蛋白 A6 和 Hsp47 在内的 21 种蛋白则与脂肪细胞大小相关。在这 27 个蛋白质表达变化中，14 个变化与 mRNA 水平的改变相关，而其余 13 个变化是蛋白质翻译或周转变化的结果。这些数据表明脂肪细胞存在内在异质性，其蛋白质表达模式存在差异，这是由与胰岛素作用和细胞脂质积累相关的转录和转录后改变引起的。
Mice with a fat-specific insulin receptor knock-out (FIRKO) exhibit a polarization of white adipose tissue into two populations of cells, one small ( diameter < 50 mu m) and one large ( diameter > 100 mum), accompanied by changes in insulin-stimulated glucose uptake, triglyceride synthesis, and lipolysis. To characterize these subclasses of adipocytes, we have used a proteomics approach in which isolated adipocytes from FIRKO and control (IR lox/lox) mice were separated by size, fractionated into cytosolic and membrane subfractions, and analyzed by sucrose gradient, SDS-PAGE, and mass spectrometry. A total of 27 alterations in protein expression at key steps in lipid and energy metabolism could be defined, which were coordinately regulated by adipocyte cell size, impaired insulin signaling, or both. Nine proteins, including vimentin, EH-domain-containing protein 2, elongation factor 2, glucose-regulated protein 78, transketolase, and succinyl-CoA transferase were primarily affected by presence or absence of insulin signaling, whereas 21 proteins, including myosin non-muscle form A, annexin 2, annexin A6, and Hsp47 were regulated in relation to adipocyte size. Of these 27 alterations in protein expression, 14 changes correlated with altered levels of mRNA, whereas the remaining 13 were the result of changes in protein translation or turnover. These data suggest an intrinsic heterogeneity in adipocytes with differences in protein expression patterns caused by transcriptional and post-transcriptional alterations related to insulin action and cellular lipid accumulation.