eIF5A Functions Globally in Translation Elongation and Termination.
eIF5A Functions Globally in Translation Elongation and Termination.
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DOI：
10.1016/j.molcel.2017.03.003
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发表时间：
2017-04-20
期刊：
影响因子：
16
通讯作者：
Green R
中科院分区：
文献类型：
--
作者：
Schuller AP;Wu CC;Dever TE;Buskirk AR;Green R
真核翻译因子eIF 5A最初被鉴定为起始因子，后来被证明可促进重复脯氨酸序列的翻译延伸。使用核糖体分析和体外生物化学的组合，我们报告了更广泛的作用eIF 5A在延长和发现一个关键功能eIF 5A在终止。eIF 5A缺失菌株的核糖体分析揭示了全局延伸缺陷，其中丰富的核糖体在许多序列处停滞，而不限于脯氨酸延伸。我们的数据还显示核糖体在终止密码子和3′ UTR处积累，表明在缺乏eIF 5A的情况下终止存在全局缺陷。使用在体外重建的翻译系统，我们发现，eIF 5A强烈促进翻译的失速序列通过分析确定，并增加肽基-tRNA水解的速率超过17倍。我们得出结论，eIF 5A功能广泛的延伸和终止，合理化其高细胞丰度和必要的性质。在这份手稿中，Schuller等人描述了翻译因子eIF 5A的活性。他们表明，eIF 5A在大多数（如果不是全部）序列中加速肽基转移，并促进肽释放。eIF 5A的这些扩展作用有助于解释其在真核生物中的基本性质和高丰度。
The eukaryotic translation factor eIF5A, originally identified as an initiation factor, was later shown to promote translation elongation of iterated proline sequences. Using a combination of ribosome profiling and in vitro biochemistry, we report a much broader role for eIF5A in elongation and uncover a critical function for eIF5A in termination. Ribosome profiling of an eIF5A-depleted strain reveals a global elongation defect, with abundant ribosomes stalling at many sequences, not limited to proline stretches. Our data also show ribosome accumulation at stop codons and in the 3′ UTR, suggesting a global defect in termination in the absence of eIF5A. Using an in vitro reconstituted translation system, we find that eIF5A strongly promotes the translation of the stalling sequences identified by profiling and increases the rate of peptidyl-tRNA hydrolysis more than 17-fold. We conclude that eIF5A functions broadly in elongation and termination, rationalizing its high cellular abundance and essential nature. In this manuscript, Schuller et al. characterize the activity of the translation factor eIF5A. They show that eIF5A accelerates peptidyl transfer at most, if not all, sequences and promotes peptide release. These expanded roles for eIF5A help to explain its essential nature and high abundance in eukaryotes.