The 1:2 complex between RavZ and LC3 reveals a mechanism for deconjugation of LC3 on the phagophore membrane
The 1:2 complex between RavZ and LC3 reveals a mechanism for deconjugation of LC3 on the phagophore membrane
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DOI：
10.1080/15548627.2016.1243199
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发表时间：
2017-01-01
期刊：
影响因子：
13.3
通讯作者：
Song, Hyun Kyu
中科院分区：
文献类型：
--
作者：
Kwon, Do Hoon;Kim, Sulhee;Song, Hyun Kyu
宿主利用巨大的自噬/自噬来清除入侵的细菌；然而，细菌也通过操纵宿主细胞的自噬机制开发了一种特殊的生存机制。一种病原体嗜肺军团菌可以通过使用特定的效应蛋白RavZ来阻止宿主细胞的自噬，RavZ能裂解吞噬体膜上磷脂酰乙醇胺连接的LC3。然而，与RavZ功能相关的详细分子机制到目前为止还不清楚。在这里，我们报道了RavZ-Lc3相互作用的生化特征，RavZ与Lc3之间1：2络合物的溶液结构，以及RavZ的晶体结构显示出不同构象的活性中心环。根据我们对RavZ和LC_3的生化、结构和细胞分析，包含LC_3-相互作用区(LIR)基序的远距离柔性N-末端和C-末端区域对于底物识别都是重要的。这些结果提示了RavZ在吞噬体膜上作用的新机制，并为了解细菌病原体如何在自噬中存活奠定了基础。
Hosts utilize macroautophagy/autophagy to clear invading bacteria; however, bacteria have also developed a specific mechanism to survive by manipulating the host cell autophagy mechanism. One pathogen, Legionella pneumophila, can hinder host cell autophagy by using the specific effector protein RavZ that cleaves phosphatidylethanolamine-conjugated LC3 on the phagophore membrane. However, the detailed molecular mechanisms associated with the function of RavZ have hitherto remained unclear. Here, we report on the biochemical characteristics of the RavZ-LC3 interaction, the solution structure of the 1:2 complex between RavZ and LC3, and crystal structures of RavZ showing different conformations of the active site loop without LC3. Based on our biochemical, structural, and cell-based analyses of RavZ and LC3, both distant flexible N- and C-terminal regions containing LC3-interacting region (LIR) motifs are important for substrate recognition. These results suggest a novel mechanism of RavZ action on the phagophore membrane and lay the groundwork for understanding how bacterial pathogens can survive autophagy.