Escape of intracellular Shigella from autophagy requires binding to cholesterol through the type III effector, IcsB
Escape of intracellular Shigella from autophagy requires binding to cholesterol through the type III effector, IcsB
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DOI：
10.1016/j.micinf.2010.06.006
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发表时间：
2010-11-01
影响因子：
5.8
通讯作者：
Allaoui, Abdelmounaaim
中科院分区：
文献类型：
--
作者：
Kayath, Christian Aime;Hussey, Seamus;Allaoui, Abdelmounaaim
IcsB是一种III型分泌系统，通过与自噬蛋白ATG5结合，帮助志贺氏菌逃避宿主自噬防御系统。我们证明了IcsB能与胆固醇特异结合。IcsB的胆固醇结合域(CBD)位于IcsB的单一酪氨酸残基Y297或Y340的288和351个特定突变之间，苯丙氨酸(F)略微减少胆固醇结合，而整个CBD的缺失或双突变Y297F Y340F强烈取消与胆固醇的相互作用确定表达IcsB突变体的志贺氏菌是否能像野生型志贺氏菌一样有效地逃避自噬。我们用稳定表达自噬标志物Lc3与GFP融合的MDAMC细胞，并用荧光显微镜定量检测细菌自噬小体的形成。突变Y297F或Y340F轻微损害IcsB的功能，而完全去除CBD或突变Y297F-Y340F显著抑制自噬逃避。此外，我们还报道了BopA与IcsB的对应突变具有相似的自噬逃避特性。包含CBD域并且还能够绑定胆固醇(C)2010年由Elsevier Masson SAS出版的巴斯德研究所保留所有权利
Type III secretion systems are present in many pathogenic bacteria and mediate the translocation of bacterial effectors into host cells Identification of host targets of these effectors is crucial for understanding bacterial virulence IcsB a type III secretion effector helps Shigella to evade the host autophagy defense system by binding to the autophagy protein Atg5 Here we show that IcsB is able to interact specifically with cholesterol The cholesterol binding domain (CBD) of IcsB is located between residues 288 and 351 Specific mutations of single tyrosine residues Y297 or Y340 of IcsB by phenylalanine (F) slightly reduced cholesterol binding whereas deletion of the entire CBD or double mutation Y297F Y340F strongly abolished interactions with cholesterol To determine whether Shigella expressing IcsB variants could evade autophagy as effectively as the wild type Shigella we infected MDAMC cells stably expressing the autophagy marker LC3 fused to GFP and bacterial autophagosome formation was quantified using fluorescence microscopy Mutation Y297F or Y340F slightly impaired IcsB function whereas complete removal of CBD or mutation Y297F-Y340F significantly impaired autophagy evasion Furthermore we report that BopA the counterpart of IcsB in Burkholderia pseudomallei with similar autophagy evading properties, contains the CBD domain and is also able to bind cholesterol (C) 2010 Institut Pasteur Published by Elsevier Masson SAS All rights reserved