Release of the export adapter, Nmd3p, from the 60S ribosomal subunit requires Rpl10p and the cytoplasmic GTPase Lsg1p
Release of the export adapter, Nmd3p, from the 60S ribosomal subunit requires Rpl10p and the cytoplasmic GTPase Lsg1p
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DOI：
10.1038/sj.emboj.7600547
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发表时间：
2005-02-09
期刊：
影响因子：
11.4
通讯作者：
Johnson, AW
中科院分区：
文献类型：
--
作者：
Hedges, J;West, M;Johnson, AW
在真核生物中，大（60S）核糖体亚基的核输出需要衔接蛋白 Nmd3p 来提供核输出信号。在这里，我们表明，在酵母中，从细胞质中的 60S 亚基释放 Nmd3p 需要核糖体蛋白 Rpl10p 和 G 蛋白 Lsg1p。 LSG1 或 RPL10 的突变阻止 Nmd3-GFP 穿梭进入细胞核并从细胞核输出 60S 前亚基。 NMD3 的过表达缓解了输出缺陷，表明 lsg1 和 rpl10 突变体中 60S 输出的阻断是由于未能回收 Nmd3p 间接导致的。 lsg1 和 rpl10 突变体中 Nmd3p 回收的缺陷和 60S 输出的阻断也被突变体 Nmd3 蛋白抑制，该蛋白在体外表现出与 60S 亚基的结合减少。我们认为，Lsg1p 从亚基中释放 Nmd3p 需要将 Rpl10p 正确加载到 60S 亚基中。这些结果表明回收 60S 输出接头和激活 60S 翻译亚基之间存在耦合。
In eukaryotes, nuclear export of the large (60S) ribosomal subunit requires the adapter protein Nmd3p to provide the nuclear export signal. Here, we show that in yeast release of Nmd3p from 60S subunits in the cytoplasm requires the ribosomal protein Rpl10p and the G-protein, Lsg1p. Mutations in LSG1 or RPL10 blocked Nmd3-GFP shuttling into the nucleus and export of pre-60S subunits from the nucleus. Overexpression of NMD3 alleviated the export defect, indicating that the block in 60S export in lsg1 and rpl10 mutants results indirectly from failing to recycle Nmd3p. The defect in Nmd3p recycling and the block in 60S export in both lsg1 and rpl10 mutants was also suppressed by mutant Nmd3 proteins that showed reduced binding to 60S subunits in vitro. We propose that the correct loading of Rpl10p into 60S subunits is required for the release of Nmd3p from subunits by Lsg1p. These results suggest a coupling between recycling the 60S export adapter and activation of 60S subunits for translation.