Comparative profiling of stress granule clearance reveals differential contributions of the ubiquitin system.
Comparative profiling of stress granule clearance reveals differential contributions of the ubiquitin system.
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DOI：
10.26508/lsa.202000927
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发表时间：
2021-05
影响因子：
4.4
通讯作者：
Buchberger A
中科院分区：
文献类型：
--
作者：
Tolay N;Buchberger A
这项研究表明，泛素缀合物与各种类型的应激颗粒，并认为一个积极的泛素系统是必需的某些类型的应激颗粒的有效清除。应激颗粒（SG）是含有非翻译mRNP复合物的细胞质凝聚物。它们由各种蛋白毒性条件如热、氧化和渗透压应激诱导。SG被认为可以保护mRNP免于降解，并使细胞在应激条件消退时能够快速恢复翻译。SG动力学受各种翻译后修饰控制，但泛素系统的作用仍有争议。在这里，我们提出了一个比较分析，解决参与的泛素系统在SG清除。使用高分辨率免疫荧光显微镜，我们发现，泛素与不同程度的热，亚砷酸盐，过氧化氢，山梨醇，或嘌呤霉素和Hsp 70抑制剂联合治疗诱导的SGs。SG相关的泛素种类包括K48-和K63-连接的缀合物，而游离的泛素没有显著富集。泛素活化酶，去泛素化酶，26 S蛋白酶体和p97/VCP的抑制损害了亚砷酸盐和热诱导的SGs的清除，而其他应激条件下诱导的SGs几乎没有影响。我们的数据强调了泛素系统在SG清除中的差异参与，这是一个重要的过程，可以防止疾病相关的异常SG的形成。
This study shows that ubiquitin conjugates associate with various types of stress granules and that an active ubiquitin system is required for the efficient clearance of some types of stress granules. Stress granules (SGs) are cytoplasmic condensates containing untranslated mRNP complexes. They are induced by various proteotoxic conditions such as heat, oxidative, and osmotic stress. SGs are believed to protect mRNPs from degradation and to enable cells to rapidly resume translation when stress conditions subside. SG dynamics are controlled by various posttranslational modifications, but the role of the ubiquitin system has remained controversial. Here, we present a comparative analysis addressing the involvement of the ubiquitin system in SG clearance. Using high-resolution immunofluorescence microscopy, we found that ubiquitin associated to varying extent with SGs induced by heat, arsenite, H2O2, sorbitol, or combined puromycin and Hsp70 inhibitor treatment. SG-associated ubiquitin species included K48- and K63-linked conjugates, whereas free ubiquitin was not significantly enriched. Inhibition of the ubiquitin activating enzyme, deubiquitylating enzymes, the 26S proteasome and p97/VCP impaired the clearance of arsenite- and heat-induced SGs, whereas SGs induced by other stress conditions were little affected. Our data underline the differential involvement of the ubiquitin system in SG clearance, a process important to prevent the formation of disease-linked aberrant SGs.