The E3 Ubiquitin Ligase Parkin Is Recruited to the 26 S Proteasome via the Proteasomal Ubiquitin Receptor Rpn13
The E3 Ubiquitin Ligase Parkin Is Recruited to the 26 S Proteasome via the Proteasomal Ubiquitin Receptor Rpn13
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DOI：
10.1074/jbc.m114.614925
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发表时间：
2015-03-20
影响因子：
4.8
通讯作者：
Husnjak, Koraljka
中科院分区：
文献类型：
--
作者：
Aguileta, Miguel A.;Korac, Jelena;Husnjak, Koraljka
背景：E3连接酶PARKIN的N末端泛素样结构域的作用尚不完全清楚。结果：帕金通过其泛素样结构域与蛋白酶体固有的泛素受体Rpn13相互作用而被招募到26个S蛋白酶体中。结论：PARKIN周转和E3连接酶活性可通过Rpn13被募集到26个S蛋白酶体中来调节。意义：Parkin-Rpn13相互作用可能被用作一种潜在的治疗策略。Park2基因的突变是一种常见的家族性帕金森病的原因，Park2基因编码环状-Hect杂交型E3泛素连接酶Parkin。通过单一和多泛素化靶蛋白，Parkin调节各种细胞过程，包括26 S蛋白酶体内蛋白质的降解，26 Protein Proteasome是一个大型的多聚体降解机器。为了进一步阐明parkin的功能，我们已经鉴定了蛋白酶体泛素受体Rpn13/ADRM1是一种parkin相互作用蛋白。我们发现Parkin的N端泛素样域(UbL)直接与Rpn13中的Pleckstrin样泛素受体(PrU)结构域结合。利用突变分析和核磁共振技术，我们发现Pru结合涉及Parkin Ub1中Ile-44周围的疏水斑块，这是泛素和Ubl结构域之间高度保守的区域。然而，与泛素相比，parkin Ubl对PrU结构域的亲和力要高出10倍以上。此外，Rpn13在细胞中的敲除增加了parkin的水平，并取消了对26个S蛋白酶体的parkin募集，使Rpn13成为parkin的主要蛋白酶体受体。相反，沉默Rpn13不会损害Parkin对线粒体的募集，也不会削弱Parkin对间氯苯肼诱导的线粒体去极化的影响。然而，它确实延迟了线粒体蛋白(TIM23、TIM44和TOM20)的清除，并促进了parkin的自素化。综上所述，这些发现暗示Rpn13将Parkin连接到26个S蛋白酶体，并在有丝分裂过程中调节线粒体蛋白质的清除。
Background: The role of the N-terminal ubiquitin-like domain of the E3 ligase parkin is not fully understood. Results: Parkin is recruited to the 26 S proteasome through the interaction of its ubiquitin-like domain with the intrinsic proteasomal ubiquitin receptor Rpn13. Conclusion: Parkin turnover and E3 ligase activity can be regulated by its recruitment to the 26 S proteasome via Rpn13. Significance: Parkin-Rpn13 interaction might be exploited as a potential therapeutic strategy.Mutations in the Park2 gene, encoding the RING-HECT hybrid E3 ubiquitin ligase parkin, are responsible for a common familial form of Parkinson disease. By mono- and polyubiquitinating target proteins, parkin regulates various cellular processes, including degradation of proteins within the 26 S proteasome, a large multimeric degradation machine. In our attempt to further elucidate the function of parkin, we have identified the proteasomal ubiquitin receptor Rpn13/ADRM1 as a parkin-interacting protein. We show that the N-terminal ubiquitin-like (Ubl) domain of parkin binds directly to the pleckstrin-like receptor for ubiquitin (Pru) domain within Rpn13. Using mutational analysis and NMR, we find that Pru binding involves the hydrophobic patch surrounding Ile-44 in the parkin Ubl, a region that is highly conserved between ubiquitin and Ubl domains. However, compared with ubiquitin, the parkin Ubl exhibits greater than 10-fold higher affinity for the Pru domain. Moreover, knockdown of Rpn13 in cells increases parkin levels and abrogates parkin recruitment to the 26 S proteasome, establishing Rpn13 as the major proteasomal receptor for parkin. In contrast, silencing Rpn13 did not impair parkin recruitment to mitochondria or parkin-mediated mitophagy upon carbonyl cyanide m-chlorophenyl hydrazone-induced mitochondrial depolarization. However, it did delay the clearance of mitochondrial proteins (TIM23, TIM44, and TOM20) and enhance parkin autoubiquitination. Taken together, these findings implicate Rpn13 in linking parkin to the 26 S proteasome and regulating the clearance of mitochondrial proteins during mitophagy.