Structural Basis of the Activation and Degradation Mechanisms of the E3 Ubiquitin Ligase Nedd4L
Structural Basis of the Activation and Degradation Mechanisms of the E3 Ubiquitin Ligase Nedd4L
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DOI：
10.1016/j.str.2014.08.016
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发表时间：
2014-10-07
期刊：
影响因子：
5.7
通讯作者：
Macias, Maria J.
中科院分区：
文献类型：
--
作者：
Escobedo, Albert;Gomes, Tiago;Macias, Maria J.
我们结合现有的生化信息和互补的生物物理技术，研究了E3泛素连接酶Nedd4L的激活和降解机制。利用核磁共振波谱，我们发现C2结构域结合Ca2+和肌醇1,4,5-三磷酸（IP3），使用与HECT结构域相互作用相同的界面。因此，我们提出从封闭形式到活性形式的转变是由IP3和Ca2+与HECT结构域结合到C2结构域的竞争调节的。我们进行了弛豫实验和分子动力学模拟来确定HECT结构的柔韧性，并观察到当展开过程启动时，其保守的PY基序可以成为溶剂暴露。与HECT-PY位点结合的WW3结构域的结构揭示了这种相互作用的细节，提出了一种可能的自动合成机制，使用两个分子，一个部分展开的分子和一个完全功能的Nedd4L对应分子。
We investigated the mechanisms of activation and degradation of the E3 ubiquitin ligase Nedd4L combining the available biochemical information with complementary biophysical techniques. Using nuclear magnetic resonance spectroscopy, we identified that the C2 domain binds Ca2+ and inositol 1,4,5-trisphosphate (IP3) using the same interface that is used to interact with the HECT domain. Thus, we propose that the transition from the closed to the active form is regulated by a competition of IP3 and Ca2+ with the HECT domain for binding to the C2 domain. We performed relaxation experiments and molecular dynamic simulations to determine the flexibility of the HECT structure and observed that its conserved PY motif can become solvent-exposed when the unfolding process is initiated. The structure of the WW3 domain bound to the HECT-PY site reveals the details of this interaction, suggesting a possible auto-ubquitination mechanism using two molecules, a partially unfolded one and a fully functional Nedd4L counterpart.