Translation termination depends on the sequential ribosomal entry of eRF1 and eRF3
Translation termination depends on the sequential ribosomal entry of eRF1 and eRF3
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DOI：
10.1093/nar/gkz177
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发表时间：
2019-05-21
影响因子：
14.9
通讯作者：
Krebber, Heike
中科院分区：
文献类型：
--
作者：
Beissel, Christian;Neumann, Bettina;Krebber, Heike
翻译终止需要eRF 1和eRF 3在终止密码子上释放多肽和tRNA。此外，需要Dbp 5/DDX 19和Rli 1/ABCE 1;然而，它们在该过程中的功能目前尚不清楚。使用在体内和体外实验的组合，我们表明，它们调节终止复合物的逐步组装。Rli 1和eRF 3-GDP首先与核糖体结合。随后，Dbp 5-ATP将eRF 1递送到终止密码子，并以这种方式防止eRF 3过早进入。Dbp 5在通过ATP水解放置eRF 1时解离。这又使得eRF 1能够接触eRF 3，因为Dbp 5和eRF 3与eRF 1的绑定是互斥的。Dbp 5引导的eRF 1递送中的缺陷导致eRF 1和eRF 3与核糖体的过早接触和过早解离以及随后的终止密码子通读。因此，逐步Dbp 5控制的终止复合物组装是必不可少的定期翻译终止事件。我们的数据进一步表明Dbp 5/DDX 19在替代翻译终止事件中的可能作用，例如在应激反应期间或在发育过程中，其将解旋酶分类为无义抑制疗法的潜在药物靶标，以治疗癌症和神经退行性疾病。
Translation termination requires eRF1 and eRF3 for polypeptide-and tRNA-release on stop codons. Additionally, Dbp5/DDX19 and Rli1/ABCE1 are required; however, their function in this process is currently unknown. Using a combination of in vivo and in vitro experiments, we show that they regulate a stepwise assembly of the termination complex. Rli1 and eRF3-GDP associate with the ribosome first. Subsequently, Dbp5-ATP delivers eRF1 to the stop codon and in this way prevents a premature access of eRF3. Dbp5 dissociates upon placing eRF1 through ATP-hydrolysis. This in turn enables eRF1 to contact eRF3, as the binding of Dbp5 and eRF3 to eRF1 is mutually exclusive. Defects in the Dbp5-guided eRF1 delivery lead to premature contact and premature dissociation of eRF1 and eRF3 from the ribosome and to subsequent stop codon readthrough. Thus, the stepwise Dbp5-controlled termination complex assembly is essential for regular translation termination events. Our data furthermore suggest a possible role of Dbp5/DDX19 in alternative translation termination events, such as during stress response or in developmental processes, which classifies the helicase as a potential drug target for nonsense suppression therapy to treat cancer and neurodegenerative diseases.