Proteasomal degradation of human release factor eRF3a regulates translation termination complex formation
Proteasomal degradation of human release factor eRF3a regulates translation termination complex formation
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DOI：
10.1261/rna.728608
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发表时间：
2008-02-01
期刊：
影响因子：
4.5
通讯作者：
Jean-Jean, Olivier
中科院分区：
文献类型：
--
作者：
Chauvin, Celine;Jean-Jean, Olivier
在真核生物中，eRF1 和 eRF3 结合在介导翻译终止的复合体中。这种复合物在体内形成的调节尚不清楚。在哺乳动物细胞中，eRF3a 的缺失会降低 eRF1 的稳定性，从而导致 eRF1 水平降低。在这里，我们研究了 eRF3a 与 eRF1 不相关时的状态。我们发现，eRF1 结合位点发生改变的 eRF3a 形式的稳定性降低，而在用蛋白酶体抑制剂 MG132 处理细胞后稳定性会增加。我们还表明，eRF1 结合发生改变的 eRF3a 形式以及野生型 eRF3a 均被多泛素化。这些结果表明，当 eRF3a 与 eRF1 不相关时，eRF3a 会被蛋白酶体降解，并表明 eRF3a 的蛋白酶体降解通过将 eRF3a 水平调整为 eRF1 的水平来控制翻译终止复合物的形成。
In eukaryotes, eRF1 and eRF3 are associated in a complex that mediates translation termination. The regulation of the formation of this complex in vivo is far from being understood. In mammalian cells, depletion of eRF3a causes a reduction of eRF1 level by decreasing its stability. Here, we investigate the status of eRF3a when not associated with eRF1. We show that eRF3a forms altered in their eRF1-binding site have a decreased stability, which increases upon cell treatment with the proteasome inhibitor MG132. We also show that eRF3a forms altered in eRF1 binding as well as wild-type eRF3a are polyubiquitinated. These results indicate that eRF3a is degraded by the proteasome when not associated with eRF1 and suggest that proteasomal degradation of eRF3a controls translation termination complex formation by adjusting the eRF3a level to that of eRF1.