Multiple post-translational modifications in hepatocyte nuclear factor 4α
Multiple post-translational modifications in hepatocyte nuclear factor 4α
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DOI：
10.1016/j.bbrc.2011.06.033
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发表时间：
2011-07-15
影响因子：
3.1
通讯作者：
Kato, Shigeaki
中科院分区：
文献类型：
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作者：
Yokoyama, Atsushi;Katsura, Shogo;Kato, Shigeaki
为了研究翻译后修饰（PTM）在肝细胞核因子4 α（HNF 4 α）介导的转录中的作用，我们采用质谱技术对HNF 4 α蛋白的翻译后修饰进行了全面的研究，共鉴定出8个PTM位点，其中包括新发现的泛素化和乙酰化位点。为了评估鉴定的PTM对HNF 4 α功能的影响，我们在鉴定的PTM位点引入点突变，并测试HNF 4 α的转录活性。在点突变中，发现赖氨酸458处的乙酰化位点在HNF 4 α介导的转录控制中具有重要意义。赖氨酸458处的乙酰化阴性突变体显示出约2倍的转录活性增加，而乙酰化模拟突变体具有降低的转录激活。此外，这种乙酰化似乎是波动的响应细胞外营养条件。因此，通过应用PTM的综合分析，在HNF 4 α中新鉴定出多种PTM，并且可以揭示HNF 4 α乙酰化的意想不到的作用。(C)2011 Elsevier Inc. All rights reserved.
To investigate the role of post-translational modifications (PTMs) in the hepatocyte nuclear factor 4 alpha (HNF4 alpha)-mediated transcription, we took a comprehensive survey of PTMs in HNF4 alpha protein by mass-spectrometry and identified totally 8 PTM sites including newly identified ubiquitilation and acetylation sites. To assess the impact of identified PTMs in HNF4 alpha-function, we introduced point mutations at the identified PTM sites and, tested transcriptional activity of the HNF4 alpha. Among the point-mutations, an acetylation site at lysine 458 was found significant in the HNF4 alpha-mediated transcriptional control. An acetylation negative mutant at lysine 458 showed an increased transcriptional activity by about 2-fold, while an acetylation mimic mutant had a lowered transcriptional activation. Furthermore, this acetylation appeared to be fluctuated in response to extracellular nutrient conditions. Thus, by applying an comprehensive analysis of PTMs, multiple PTMs were newly identified in HNF4 alpha and unexpected role of an HNF4 alpha acetylation could be uncovered. (C) 2011 Elsevier Inc. All rights reserved.