Structural and kinetic analysis of the COP9-Signalosome activation and the cullin-RING ubiquitin ligase deneddylation cycle
Structural and kinetic analysis of the COP9-Signalosome activation and the cullin-RING ubiquitin ligase deneddylation cycle
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DOI：
10.1101/046367
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发表时间：
2016-03
期刊：
影响因子：
7.7
通讯作者：
Ruzbeh Mosadeghi;Kurt Reichermeier;Martin Winkler;Anne Schreiber;Justin M. Reitsma;Yaru Zhang;Florian Steng
中科院分区：
文献类型：
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作者：
Ruzbeh Mosadeghi;Kurt Reichermeier;Martin Winkler;Anne Schreiber;Justin M. Reitsma;Yaru Zhang;Florian Steng
COP9-Signalosome(CSN)通过从cullins上切割Nedd8来调节cullin环泛素连接酶(CRL)的活性和组装。游离CSN是自动抑制的，目前尚不清楚它是如何被激活的。我们结合结构和动力学分析来确定有助于CSN激活和Nedd8去卷曲的机制。CSN和去碱化底物在结合时都经历了很大的构象变化，其中Csn2和CSN4的N-末端结构域以及Rbx1的环结构域在形成高亲和力、完全活性的复合体方面发挥了重要作用。环状结构域对脱染作用至关重要，部分是通过涉及CSN6插入-2的构象变化来发挥作用的。NEDD8的去结合和活性部位锌的重新结合被自身抑制的Csn5谷氨酸-104降低了约100倍，导致其迅速从活性部位排出。这些机制共同促进了细胞CRL网络的快速重构，从而实现了一个动态的去动力-分解循环。
The COP9-Signalosome (CSN) regulates cullin–RING ubiquitin ligase (CRL) activity and assembly by cleaving Nedd8 from cullins. Free CSN is autoinhibited, and it remains unclear how it becomes activated. We combine structural and kinetic analyses to identify mechanisms that contribute to CSN activation and Nedd8 deconjugation. Both CSN and neddylated substrate undergo large conformational changes upon binding, with important roles played by the N-terminal domains of Csn2 and Csn4 and the RING domain of Rbx1 in enabling formation of a high affinity, fully active complex. The RING domain is crucial for deneddylation, and works in part through conformational changes involving insert-2 of Csn6. Nedd8 deconjugation and re-engagement of the active site zinc by the autoinhibitory Csn5 glutamate-104 diminish affinity for Cul1/Rbx1 by ~100-fold, resulting in its rapid ejection from the active site. Together, these mechanisms enable a dynamic deneddylation-disassembly cycle that promotes rapid remodeling of the cellular CRL network.