Novel N-terminal and Lysine Methyltransferases That Target Translation Elongation Factor 1A in Yeast and Human
Novel N-terminal and Lysine Methyltransferases That Target Translation Elongation Factor 1A in Yeast and Human
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DOI：
10.1074/mcp.m115.052449
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发表时间：
2016-01-01
影响因子：
7
通讯作者：
Wilkins, Marc R.
中科院分区：
文献类型：
--
作者：
Hamey, Joshua J.;Winter, Daniel L.;Wilkins, Marc R.
真核细胞延伸因子1A（eEF 1A）是一种重要的高度甲基化的蛋白质，其通过将氨酰-tRNA递送到核糖体来促进翻译延伸。在这里，我们报告了一个新的真核蛋白N-末端甲基转移酶，酿酒酵母YLR 285 W，甲基化eEF 1A在以前未描述的高化学计量的N-末端位点和相邻的赖氨酸。YLR 285 W的缺失导致体内N-末端和赖氨酸甲基化的丧失，而YLR 285 W的过表达导致这些位点甲基化的增加。这通过重组YLR 285 W对eEF 1A的体外甲基化证实。因此，我们将YLR 285 W命名为延伸因子甲基转移酶7（Efm 7）。该酶是一种新型的真核N-末端甲基转移酶，与其他三种已知的真核N-末端甲基转移酶不同，其底物不具有N-末端[A/P/S]-P-K基序。我们发现eEF 1A的N末端甲基化也存在于人类中;这种在很长进化距离内的保守性表明它具有功能重要性。这项研究还报告了eEF 1A中Lys（79）的三甲基化在酵母和人类中是保守的。负责人eEF 1A的Lys（79）甲基化的甲基转移酶被证明是N6 AMT 2，先前被证明是一种假定的N（6）-腺嘌呤特异性DNA甲基转移酶。它是最近描述的酵母Efm 5的直接直系同源物，我们表明Efm 5和N6 AMT 2可以在体外甲基化来自任一物种的eEF 1A。因此，我们将N6 AMT 2重命名为eEF 1A-KMT 1。包括目前的工作，酵母eEF 1A现在被证明是由五种不同的甲基转移酶甲基化，使其成为为数不多的真核蛋白被广泛甲基化的独立酶。这意味着更广泛的调控eEF 1A的翻译后修饰比以前认识到的。
Eukaryotic elongation factor 1A (eEF1A) is an essential, highly methylated protein that facilitates translational elongation by delivering aminoacyl-tRNAs to ribosomes. Here, we report a new eukaryotic protein N-terminal methyltransferase, Saccharomyces cerevisiae YLR285W, which methylates eEF1A at a previously undescribed high-stoichiometry N-terminal site and the adjacent lysine. Deletion of YLR285W resulted in the loss of N-terminal and lysine methylation in vivo, whereas overexpression of YLR285W resulted in an increase of methylation at these sites. This was confirmed by in vitro methylation of eEF1A by recombinant YLR285W. Accordingly, we name YLR285W as elongation factor methyltransferase 7 (Efm7). This enzyme is a new type of eukaryotic N-terminal methyltransferase as, unlike the three other known eukaryotic N-terminal methyltransferases, its substrate does not have an N-terminal [A/P/S]-P-K motif. We show that the N-terminal methylation of eEF1A is also present in human; this conservation over a large evolutionary distance suggests it to be of functional importance. This study also reports that the trimethylation of Lys(79) in eEF1A is conserved from yeast to human. The methyltransferase responsible for Lys(79) methylation of human eEF1A is shown to be N6AMT2, previously documented as a putative N(6)-adenine-specific DNA methyltransferase. It is the direct ortholog of the recently described yeast Efm5, and we show that Efm5 and N6AMT2 can methylate eEF1A from either species in vitro. We therefore rename N6AMT2 as eEF1A-KMT1. Including the present work, yeast eEF1A is now documented to be methylated by five different methyltransferases, making it one of the few eukaryotic proteins to be extensively methylated by independent enzymes. This implies more extensive regulation of eEF1A by this posttranslational modification than previously appreciated.