Niclosamide prevents the formation of large ubiquitin-containing aggregates caused by proteasome inhibition.
Niclosamide prevents the formation of large ubiquitin-containing aggregates caused by proteasome inhibition.
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DOI：
10.1371/journal.pone.0014410
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发表时间：
2010-12-23
期刊：
影响因子：
3.7
通讯作者：
Mayor T
中科院分区：
文献类型：
--
作者：
Gies E;Wilde I;Winget JM;Brack M;Rotblat B;Novoa CA;Balgi AD;Sorensen PH;Roberge M;Mayor T
蛋白质聚集是许多神经退行性疾病的标志，并且与不能降解错误折叠和受损的蛋白质有关。在细胞中，异常蛋白质被主要靶向短寿命蛋白质的泛素蛋白酶体系统降解，或被主要清除长寿命和难溶性蛋白质的溶酶体降解。这两个系统是相互关联的，在某些情况下，自噬可以将蛋白酶体底物重定向到溶酶体。为了更好地理解这两个系统之间的相互作用，我们建立了一个神经母细胞瘤细胞群稳定表达GFP-泛素融合蛋白。我们发现，抑制蛋白酶体导致形成大的泛素包含夹杂物伴随着较低的溶解度的泛素缀合物。引人注目的是，含泛素的聚集体的形成不需要疾病特异性蛋白质的异位表达。此外，这些由蛋白酶体抑制引起的聚集包涵体的形成需要泛素的赖氨酸63（K63）。然后，我们评估了刺激自噬的选定化合物，发现抗蠕虫化学品氯硝柳胺可防止蛋白酶体抑制诱导的大聚集体形成，而原型mTORC 1抑制剂雷帕霉素没有明显的作用。氯硝柳胺还阻止了蛋白酶体抑制后聚泛素化蛋白和p62的积累。此外，氯硝柳胺诱导细胞中溶酶体分布的变化，在不存在蛋白酶体活性的情况下，可能有利于泛素化蛋白在形成大的聚集体之前被摄取到溶酶体中。我们的研究结果表明，蛋白酶体抑制剂引起的组织培养细胞中含有聚集体的大泛素的形成，即使在疾病特异性蛋白的情况下。此外，我们的研究表明，自噬诱导化合物氯硝柳胺可能会促进选择性清除泛素化蛋白的蛋白酶体活性的情况下。
Protein aggregation is a hallmark of many neurodegenerative diseases and has been linked to the failure to degrade misfolded and damaged proteins. In the cell, aberrant proteins are degraded by the ubiquitin proteasome system that mainly targets short-lived proteins, or by the lysosomes that mostly clear long-lived and poorly soluble proteins. Both systems are interconnected and, in some instances, autophagy can redirect proteasome substrates to the lysosomes. To better understand the interplay between these two systems, we established a neuroblastoma cell population stably expressing the GFP-ubiquitin fusion protein. We show that inhibition of the proteasome leads to the formation of large ubiquitin-containing inclusions accompanied by lower solubility of the ubiquitin conjugates. Strikingly, the formation of the ubiquitin-containing aggregates does not require ectopic expression of disease-specific proteins. Moreover, formation of these focused inclusions caused by proteasome inhibition requires the lysine 63 (K63) of ubiquitin. We then assessed selected compounds that stimulate autophagy and found that the antihelmintic chemical niclosamide prevents large aggregate formation induced by proteasome inhibition, while the prototypical mTORC1 inhibitor rapamycin had no apparent effect. Niclosamide also precludes the accumulation of poly-ubiquitinated proteins and of p62 upon proteasome inhibition. Moreover, niclosamide induces a change in lysosome distribution in the cell that, in the absence of proteasome activity, may favor the uptake into lysosomes of ubiquitinated proteins before they form large aggregates. Our results indicate that proteasome inhibition provokes the formation of large ubiquitin containing aggregates in tissue culture cells, even in the absence of disease specific proteins. Furthermore our study suggests that the autophagy-inducing compound niclosamide may promote the selective clearance of ubiquitinated proteins in the absence of proteasome activity.
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影响因子：
3.7
作者：
Balgi AD;Fonseca BD;Donohue E;Tsang TC;Lajoie P;Proud CG;Nabi IR;Roberge M
通讯作者：
Roberge M
DOI：
10.1073/pnas.0500485102
发表时间：
2005-03-29
影响因子：
11.1
作者：
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影响因子：
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作者：
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影响因子：
3.9
作者：
Kim, Insil;Rodriguez-Enriquez, Sara;Lemasters, John J.
通讯作者：
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影响因子：
56.9
作者：
CHAU, V;TOBIAS, JW;VARSHAVSKY, A
通讯作者：
VARSHAVSKY, A