Methylation by Set9 modulates FoxO3 stability and transcriptional activity.
Methylation by Set9 modulates FoxO3 stability and transcriptional activity.
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DOI：
10.18632/aging.100471
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发表时间：
2012-07
期刊：
影响因子：
--
通讯作者：
Brunet A
中科院分区：
文献类型：
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作者：
Calnan DR;Webb AE;White JL;Stowe TR;Goswami T;Shi X;Espejo A;Bedford MT;Gozani O;Gygi SP;Brunet A
转录因子FoxO家族通过调节多种靶基因的表达在长寿和肿瘤抑制中起重要作用。最近发现FoxO 3与人类的极端长寿有关，并调节哺乳动物成体干细胞库的稳态，这可能有助于长寿。FoxO 3的活性受到多种翻译后修饰的控制，这些修饰被认为是影响FoxO 3亚细胞定位、DNA结合能力、蛋白质-蛋白质相互作用和蛋白质稳定性的“密码”。赖氨酸甲基化是组蛋白上的一种重要的翻译后修饰，它调节染色质的可及性，是“组蛋白密码”的关键部分。然而，赖氨酸甲基化是否在调节FoxO 3活性中起作用从未被研究过。在这里，我们表明，甲基转移酶Set 9直接甲基化FoxO 3在体外和细胞中。使用串联质谱和甲基特异性抗体的组合，我们发现，Set 9甲基化FoxO 3在一个单一的残基，赖氨酸271，一个网站以前已知的Sirt 1脱乙酰化。Set 9对FoxO 3的甲基化降低了FoxO 3蛋白的稳定性，同时适度增加了FoxO 3的转录活性。通过甲基化调节FoxO 3的稳定性和活性对于微调细胞对应激刺激的反应可能是至关重要的，这反过来可能影响FoxO 3促进肿瘤抑制和长寿的能力。
The FoxO family of transcription factors plays an important role in longevity and tumor suppression by regulating the expression of a wide range of target genes. FoxO3 has recently been found to be associated with extreme longevity in humans and to regulate the homeostasis of adult stem cell pools in mammals, which may contribute to longevity. The activity of FoxO3 is controlled by a variety of post-translational modifications that have been proposed to form a ‘code’ affecting FoxO3 subcellular localization, DNA binding ability, protein-protein interactions and protein stability. Lysine methylation is a crucial post-translational modification on histones that regulates chromatin accessibility and is a key part of the ‘histone code’. However, whether lysine methylation plays a role in modulating FoxO3 activity has never been examined. Here we show that the methyltransferase Set9 directly methylates FoxO3 in vitro and in cells. Using a combination of tandem mass spectrometry and methyl-specific antibodies, we find that Set9 methylates FoxO3 at a single residue, lysine 271, a site previously known to be deacetylated by Sirt1. Methylation of FoxO3 by Set9 decreases FoxO3 protein stability, while moderately increasing FoxO3 transcriptional activity. The modulation of FoxO3 stability and activity by methylation may be critical for fine-tuning cellular responses to stress stimuli, which may in turn affect FoxO3's ability to promote tumor suppression and longevity.