Succination of protein thiols during adipocyte maturation - A biomarker of mitochondrial stress
Succination of protein thiols during adipocyte maturation - A biomarker of mitochondrial stress
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DOI：
10.1074/jbc.m703551200
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发表时间：
2007-11-23
影响因子：
4.8
通讯作者：
Frizzell, Norma
中科院分区：
文献类型：
--
作者：
Nagai, Ryoji;Brock, Jonathan W.;Frizzell, Norma
虽然肥胖是2型糖尿病发展的危险因素，并且晚期糖氧化和脂氧化终产物对蛋白质的化学修饰与糖尿病并发症的发展有关，但对脂肪细胞或脂肪组织中蛋白质的化学修饰知之甚少。在这项研究中，我们发现S-（2-琥珀酰）半胱氨酸（2SC）是由克雷布斯循环中间体富马酸对蛋白质进行化学修饰的产物，在3T3-L1成纤维细胞向脂肪细胞成熟过程中显著增加。在含有30 mM葡萄糖的培养基中，富马酸浓度增加>= 5倍，脂肪细胞中的2sc蛋白比在相同高葡萄糖培养基中生长的未分化成纤维细胞增加>= 10倍。脂肪细胞成熟过程中培养基中葡萄糖浓度的升高与2SC的增加相关，而糖氧化和脂肪氧化最终产物n -（羧甲基）赖氨酸和n -（羧乙基）赖氨酸的浓度在这些条件下保持不变。采用单、双向电泳分离脂肪细胞蛋白，用抗2sc多克隆抗体检测与60个2sc蛋白相似的脂肪细胞蛋白。通过基质辅助激光解吸电离飞行时间/飞行时间质谱法鉴定了几个突出的和良好分解的蛋白质。这些蛋白质包括细胞骨架蛋白、酶、热休克蛋白和伴侣蛋白、调节蛋白和脂肪酸结合蛋白。我们认为富马酸盐和2SC的增加是脂肪细胞在脂肪形成过程中线粒体应激的结果，2SC可能是肥胖、胰岛素抵抗和糖尿病中线粒体应激的有用生物标志物。
Although obesity is a risk factor for development of type 2 diabetes and chemical modification of proteins by advanced glycoxidation and lipoxidation end products is implicated in the development of diabetic complications, little is known about the chemical modification of proteins in adipocytes or adipose tissue. In this study we show that S-(2-succinyl) cysteine (2SC), the product of chemical modification of proteins by the Krebs cycle intermediate, fumarate, is significantly increased during maturation of 3T3-L1 fibroblasts to adipocytes. Fumarate concentration increased >= 5-fold during adipogenesis in medium containing 30 mM glucose, producing a >= 10-fold increase in 2SC-proteins in adipocytes compared with undifferentiated fibroblasts grown in the same high glucose medium. The elevated glucose concentration in the medium during adipocyte maturation correlated with the increase in 2SC, whereas the concentration of the advanced glycoxidation and lipoxidation end products, N-is an element of-(carboxymethyl)lysine and N-is an element of-(carboxyethyl)lysine, was unchanged under these conditions. Adipocyte proteins were separated by one- and two-dimensional electrophoresis and similar to 60 2SC-proteins were detected using an anti-2SC polyclonal antibody. Several of the prominent and well resolved proteins were identified by matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry. These include cytoskeletal proteins, enzymes, heat shock and chaperone proteins, regulatory proteins, and a fatty acid-binding protein. We propose that the increase in fumarate and 2SC is the result of mitochondrial stress in the adipocyte during adipogenesis and that 2SC may be a useful biomarker of mitochondrial stress in obesity, insulin resistance, and diabetes.