Disruption of the autoinhibited state primes the E3 ligase parkin for activation and catalysis.
Disruption of the autoinhibited state primes the E3 ligase parkin for activation and catalysis.
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DOI：
10.15252/embj.201592337
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发表时间：
2015-10-14
期刊：
影响因子：
--
通讯作者：
Walden H
中科院分区：
文献类型：
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作者：
Kumar A;Aguirre JD;Condos TE;Martinez-Torres RJ;Chaugule VK;Toth R;Sundaramoorthy R;Mercier P;Knebel A;Spratt DE;Barber KR;Shaw GS;Walden H
PARK2基因在50%的常染色体隐性青少年帕金森病（ARJP）病例中发生突变。它编码parkin，一种RBR家族的E3泛素连接酶。Parkin处于自抑制状态，通过其n端泛素样（Ubl）结构域的磷酸化和磷泛素的结合而激活。我们描述了人类parkin在完全抑制状态下的1.8 Å晶体结构，并确定了维持parkin抑制的关键界面。我们确定了磷泛素结合界面，为磷泛素- parkin复合物提供了一个模型，并展示了Ubl结构域的磷酸化如何启动parkin以实现最佳的磷泛素结合。此外，我们证明了磷泛素的添加通过结构损失导致Ubl结构域的位移，揭示了E2 ~ Ub偶联物使用的泛素结合位点，从而导致活性parkin。我们发现Ubl结构域的作用是在没有磷酸化信号的情况下阻止parkin的活性，并提出了parkin抑制的模型，优化了磷泛素的募集，释放了Ubl结构域的抑制，并与E2 ~ Ub偶联物结合。综上所述，该模型提供了激活帕金的机制框架。
The PARK2 gene is mutated in 50% of autosomal recessive juvenile parkinsonism (ARJP) cases. It encodes parkin, an E3 ubiquitin ligase of the RBR family. Parkin exists in an autoinhibited state that is activated by phosphorylation of its N-terminal ubiquitin-like (Ubl) domain and binding of phosphoubiquitin. We describe the 1.8 Å crystal structure of human parkin in its fully inhibited state and identify the key interfaces to maintain parkin inhibition. We identify the phosphoubiquitin-binding interface, provide a model for the phosphoubiquitin–parkin complex and show how phosphorylation of the Ubl domain primes parkin for optimal phosphoubiquitin binding. Furthermore, we demonstrate that the addition of phosphoubiquitin leads to displacement of the Ubl domain through loss of structure, unveiling a ubiquitin-binding site used by the E2∼Ub conjugate, thus leading to active parkin. We find the role of the Ubl domain is to prevent parkin activity in the absence of the phosphorylation signals, and propose a model for parkin inhibition, optimization for phosphoubiquitin recruitment, release of inhibition by the Ubl domain and engagement with an E2∼Ub conjugate. Taken together, this model provides a mechanistic framework for activating parkin.