Hydrogen peroxide stimulates ubiquitin-conjugating activity and expression of genes for specific E2 and E3 proteins in skeletal muscle myotubes
Hydrogen peroxide stimulates ubiquitin-conjugating activity and expression of genes for specific E2 and E3 proteins in skeletal muscle myotubes
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DOI：
10.1152/ajpcell.00129.2003
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发表时间：
2003-10-01
影响因子：
5.5
通讯作者：
Reid, MB
中科院分区：
文献类型：
--
作者：
Li, YP;Chen, YL;Reid, MB
活性氧（ROS）被认为促进慢性消耗性疾病中的肌肉萎缩，但其潜在机制尚未确定。在这里，我们表明H2O2通过转录调节将泛素结合到肌肉蛋白的酶（E2和E3蛋白）来刺激泛素与肌肉蛋白的结合。C2Cl2肌管与100 muM H2O2孵育增加了全细胞提取物中i -125标记的泛素与肌肉蛋白的结合率。这种反应需要暴露在H2O2中至少4小时，并持续至少24小时。用环己亚胺或放线菌素D预孵育肌管可阻断H2O2对泛素偶联活性的刺激，这表明基因转录是必需的。Northern blot分析显示，H2O2上调了被认为调节肌肉分解代谢的特定E3和E2蛋白的表达，包括atrogin1/MAFbx、MuRF1和E2（14k）。这些结果表明，ROS通过上调泛素偶联系统刺激骨骼肌中的蛋白质分解代谢。
Reactive oxygen species (ROS) are thought to promote muscle atrophy in chronic wasting diseases, but the underlying mechanism has not been determined. Here we show that H2O2 stimulates ubiquitin conjugation to muscle proteins through transcriptional regulation of the enzymes (E2 and E3 proteins) that conjugate ubiquitin to muscle proteins. Incubation of C2Cl2 myotubes with 100 muM H2O2 increased the rate of I-125-labeled ubiquitin conjugation to muscle proteins in whole cell extracts. This response required at least 4-h exposure to H2O2 and persisted for at least 24 h. Preincubating myotubes with cycloheximide or actinomycin D blocked H2O2 stimulation of ubiquitin-conjugating activity, suggesting that gene transcription is required. Northern blot analyses revealed that H2O2 upregulates expression of specific E3 and E2 proteins that are thought to regulate muscle catabolism, including atrogin1/MAFbx, MuRF1, and E2(14k). These results suggest that ROS stimulate protein catabolism in skeletal muscle by upregulating the ubiquitin conjugation system.