Insertion of the Biogenesis Factor Rei1 Probes the Ribosomal Tunnel during 60S Maturation
Insertion of the Biogenesis Factor Rei1 Probes the Ribosomal Tunnel during 60S Maturation
复制标题
DOI：
10.1016/j.cell.2015.11.027
复制
发表时间：
2016-01-14
期刊：
影响因子：
64.5
通讯作者：
Ban, Nenad
中科院分区：
文献类型：
--
作者：
Greber, Basil Johannes;Gerhardy, Stefan;Ban, Nenad
真核生物核糖体的生物发生依赖于数百个组装因子来产生功能性的40 S和60 S核糖体亚基。60 S亚基生物合成的最后阶段是细胞质成熟，包括60 S亚基功能中心的校正和几种核糖体生物合成因子的释放。我们报告的冷冻电子显微镜（cryo-EM）结构的酵母60 S亚基在复杂的生物合成因子Rei 1，Arx 1，和Alb 1在3.4埃的分辨率。除了由Alb 1形成的相互作用网络之外，该结构还揭示了确保核糖体多肽出口通道完整性的机制。Arx 1探测隧道出口周围的整套内环蛋白，Rei 1的C末端深深插入核糖体隧道中，在那里它几乎沿着其整个长度形成特异性接触。我们提供的遗传和生化证据表明，未能插入Rei 1的C末端排除了60 S成熟的后续步骤。
Eukaryotic ribosome biogenesis depends on several hundred assembly factors to produce functional 40S and 60S ribosomal subunits. The final phase of 60S subunit biogenesis is cytoplasmic maturation, which includes the proofreading of functional centers of the 60S subunit and the release of several ribosome biogenesis factors. We report the cryo-electron microscopy (cryo-EM) structure of the yeast 60S subunit in complex with the biogenesis factors Rei1, Arx1, and Alb1 at 3.4 angstrom resolution. In addition to the network of interactions formed by Alb1, the structure reveals a mechanism for ensuring the integrity of the ribosomal polypeptide exit tunnel. Arx1 probes the entire set of inner-ring proteins surrounding the tunnel exit, and the C terminus of Rei1 is deeply inserted into the ribosomal tunnel, where it forms specific contacts along almost its entire length. We provide genetic and biochemical evidence that failure to insert the C terminus of Rei1 precludes subsequent steps of 60S maturation.