Ultrastructural insights into pathogen clearance by autophagy.
Ultrastructural insights into pathogen clearance by autophagy.
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DOI：
10.1111/tra.12723
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发表时间：
2020-04
期刊：
影响因子：
--
通讯作者：
Buss F
中科院分区：
文献类型：
--
作者：
Kishi-Itakura C;Ktistakis NT;Buss F
自噬保护细胞免受细菌如沙门氏菌在胞质溶胶中的增殖。从受损的含沙门氏菌的空泡（SCV）中逃逸后，暴露出与半乳糖凝集素-8结合的管腔聚糖，宿主细胞泛素化机制在胞质细菌周围沉积了一层致密的泛素。与其他自噬相关膜相关的这种泛素涂层的性质和空间分布尚不清楚。使用透射电子显微镜，我们确定了泛素的准确定位，破裂的SCV膜和吞噬细胞周围的胞质沙门氏菌。泛素主要不存在于沙门氏菌表面，但富集在片段化的SCV上。没有SCV的胞质细菌被吞噬细胞靶向的效率较低。单个噬菌体中含有单个细菌，但多个细菌可存在于周长达30 μm的大自噬空泡中。这些大的吞噬细胞遵循被吞噬的细菌的轮廓，它们经常与内质网膜密切相关，并且在它们内部，SCV的残余物与每个被吞噬的颗粒相关。我们的数据表明，沙门氏菌SCV在自噬吞噬细胞的形成中起着重要作用，并突出了外源性和线粒体自噬之间进化保守的平行机制，片段化的SCV和受损的线粒体外膜具有相似的功能。嗜异性是一种特异性的选择性自噬途径，用于细胞防御病原体。泛素与侵入性细菌的结合是嗜外食的一个重要步骤，然而，泛素外壳的空间分布仍不清楚。在这里，我们使用电子显微镜来分析沙门氏菌宿主膜系统的拓扑结构和泛素的分布。我们的研究结果表明，破裂的沙门氏菌空泡的蛋白质，而不是细菌表面蛋白是主要的泛素化目标。
Autophagy defends cells against proliferation of bacteria such as Salmonella in the cytosol. After escape from a damaged Salmonella‐containing vacuole (SCV) exposing luminal glycans that bind to Galectin‐8, the host cell ubiquitination machinery deposits a dense layer of ubiquitin around the cytosolic bacteria. The nature and spatial distribution of this ubiquitin coat in relation to other autophagy‐related membranes are unknown. Using transmission electron microscopy, we determined the exact localisation of ubiquitin, the ruptured SCV membrane and phagophores around cytosolic Salmonella. Ubiquitin was not predominantly present on the Salmonella surface, but enriched on the fragmented SCV. Cytosolic bacteria without SCVs were less efficiently targeted by phagophores. Single bacteria were contained in single phagophores but multiple bacteria could be within large autophagic vacuoles reaching 30 μm in circumference. These large phagophores followed the contour of the engulfed bacteria, they were frequently in close association with endoplasmic reticulum membranes and, within them, remnants of the SCV were seen associated with each engulfed particle. Our data suggest that the Salmonella SCV has a major role in the formation of autophagic phagophores and highlight evolutionary conserved parallel mechanisms between xenophagy and mitophagy with the fragmented SCV and the damaged outer mitochondrial membrane serving similar functions. Xenophagy is a specialised selective autophagy pathway for the cellular defence against pathogens. The conjugation of ubiquitin to invasive bacteria is an important step in xenophagy, however, the spatial distribution of the ubiquitin coat remains unclear. Here, we used electron microscopy to analyse the topology of the Salmonella‐host membrane system and the distribution of ubiquitin. Our results demonstrate that proteins of the ruptured Salmonella‐containing vacuole rather than bacterial surface proteins are the major ubiquitination target.
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DOI：
10.1126/science.1233028
发表时间：
2013-05-10
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Randow F;MacMicking JD;James LC
通讯作者：
James LC
影响因子：
3.1
作者：
Brumell, JH;Tang, P;Finlay, BB
通讯作者：
Finlay, BB
影响因子：
11.8
作者：
Zachari, Maria;Gudmundsson, Sigurdur R.;Ktistakis, Nicholas T.
通讯作者：
Ktistakis, Nicholas T.
影响因子：
16
作者：
Ravenhill, Benjamin J.;Boyle, Keith B.;Randow, Felix
通讯作者：
Randow, Felix
DOI：
10.1038/nrmicro3160
发表时间：
2014-03
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
Huang J;Brumell JH
通讯作者：
Brumell JH