Cell cycle-regulated modification of the ribosome by a variant multiubiquitin chain
Cell cycle-regulated modification of the ribosome by a variant multiubiquitin chain
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DOI：
10.1016/s0092-8674(00)00011-8
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发表时间：
2000-07-07
期刊：
影响因子：
64.5
通讯作者：
Finley, D
中科院分区：
文献类型：
--
作者：
Spence, J;Gali, RR;Finley, D
泛素与核糖体大亚基L28连接，形成S中最丰富的泛素-蛋白缀合物。啤酒。L28的人类直系同源物也是泛素化的，表明这种修饰在进化中是高度保守的。在酵母细胞周期的S期，L28被强烈泛素化，而在G（1）细胞中观察到L28泛素化水平降低。L28泛素化被泛素中的Lys 63至Arg取代所抑制，表明L28被变体Lys 63连接的多泛素链修饰。泛素的K63 R突变体在体内和体外显示核糖体功能缺陷，包括对翻译抑制剂的显着敏感性。L28和其他核糖体蛋白一样，是代谢稳定的。因此，这些数据表明多泛素链的调节作用是可逆的，并且不起作用以靶向受体蛋白进行降解。
Ubiquitin is ligated to L28, a component of the large ribosomal subunit, to form the most abundant ubiquitin-protein conjugate in S. cerevisiae. The human ortholog of L28 is also ubiquitinated, indicating that this modification is highly conserved in evolution. During S phase of the yeast cell cycle, L28 is strongly ubiquitinated, while reduced levels of L28 ubiquitination are observed in G(1) cells. L28 ubiquitination is inhibited by a Lys63 to Arg substitution in ubiquitin, indicating that L28 is modified by a variant, Lys63-linked multiubiquitin chain. The K63R mutant of ubiquitin displays defects in ribosomal function in vivo and in vitro, including a dramatic sensitivity to translational inhibitors. L28, like other ribosomal proteins, is metabolically stable. Therefore, these data suggest a regulatory role for multiubiquitin chains that is reversible and does not function to target the acceptor protein for degradation.