Is the Rsp5 ubiquitin ligase involved in the regulation of ribophagy?
Is the Rsp5 ubiquitin ligase involved in the regulation of ribophagy?
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DOI：
10.4161/auto.6603
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发表时间：
2008-08-16
期刊：
影响因子：
13.3
通讯作者：
Peter, Matthias
中科院分区：
文献类型：
--
作者：
Kraft, Claudine;Peter, Matthias
在营养限制条件下，细胞质组分被随机隔离到称为自噬体的双膜囊泡中，并被递送到溶酶体/液泡中进行降解和再循环。然而，在过去的几年中，已经观察到，一些细胞质组分，如细胞器，病原体或特定的蛋白质复合物也可以选择性地通过自噬相关途径降解（参考文献1）。我们最近已经证明，在S。在酿酒酵母中，成熟的核糖体在饥饿条件下通过自噬进行这种选择性降解，我们称之为“核糖体自噬”。（2）通过遗传学筛选，我们发现60 S核糖体大亚基的选择性降解依赖于泛素蛋白酶Ubp 3及其辅因子Bre 5，这意味着食核糖体是由泛素依赖性步骤调控的。有趣的是，几个泛素化的蛋白质积累在核糖体组分分离的ubp 3 δ细胞，这表明泛素的ribophagy的调节可能是直接的。在这里，我们提出的数据的潜在作用的泛素连接酶Rsp 5作为一个积极的调节ribophagy，并讨论了可能参与的泛素作为一个信号分子在这个过程中。
Under nutrient limiting conditions, cytoplasmic components are randomly sequestered into double-membrane vesicles called autophagosomes and delivered to the lysosome/vacuole for degradation and recycling. In the last few years, however, it has been observed that several cytoplasmic components such as organelles, pathogens or specific protein complexes can also be selectively targeted for degradation by autophagy-related pathways (reviewed in ref. 1). We have recently shown that in S. cerevisiae, mature ribosomes are subject to such selective degradation by autophagy under starvation conditions, in a process that we termed 'ribophagy.'(2) By genetic screening, we found that selective degradation of 60S large ribosomal subunits depends on the ubiquitin protease Ubp3 and its cofactor Bre5, implying that ribophagy is regulated by ubiquitin-dependent steps. Interestingly, several ubiquitinated proteins accumulate in ribosome fractions isolated from ubp3 Delta cells, suggesting that the regulation of ribophagy by ubiquitin may be direct. Here we present data on a potential role of the ubiquitin ligase Rsp5 as a positive regulator of ribophagy, and discuss the possible involvement of ubiquitin as a signaling molecule in this process.