Kinetic analysis reveals the ordered coupling of translation termination and ribosome recycling in yeast
Kinetic analysis reveals the ordered coupling of translation termination and ribosome recycling in yeast
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DOI：
10.1073/pnas.1113956108
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发表时间：
2011-12-20
影响因子：
11.1
通讯作者：
Green, Rachel
中科院分区：
文献类型：
--
作者：
Shoemaker, Christopher J.;Green, Rachel
尽管在细菌系统中已有明确的定义，但真核细胞中核糖体回收的分子机制才刚刚开始被探索。最近的研究提出了真核终止因子 eRF1 和 eRF3（以及相关因子 Dom34 和 Hbs1）在下游回收过程中的直接作用；然而，我们对真核生物终止和回收之间联系的理解是有限的。在这里，使用体外重建的酵母翻译系统，我们确定了多功能 ABC 家族蛋白 Rli1 在刺激酵母中 eRF1 介导的终止和核糖体回收中的关键作用。通过随后的动力学分析，我们发现了一个监管特征网络，为终止和回收事件如何强制排序提供了机械见解。这些结果建立了一个模型，其中真核终止和再循环并不是像细菌中那样明确划分的事件，而是同一释放因子介导过程的耦合阶段。
Although well defined in bacterial systems, the molecular mechanisms underlying ribosome recycling in eukaryotic cells have only begun to be explored. Recent studies have proposed a direct role for eukaryotic termination factors eRF1 and eRF3 (and the related factors Dom34 and Hbs1) in downstream recycling processes; however, our understanding of the connection between termination and recycling in eukaryotes is limited. Here, using an in vitro reconstituted yeast translation system, we identify a key role for the multifunctional ABC-family protein Rli1 in stimulating both eRF1-mediated termination and ribosome recycling in yeast. Through subsequent kinetic analysis, we uncover a network of regulatory features that provides mechanistic insight into how the events of termination and recycling are obligately ordered. These results establish a model in which eukaryotic termination and recycling are not clearly demarcated events, as they are in bacteria, but coupled stages of the same release-factor mediated process.