Bajunaid Waad, Haidar-Ahmad Nathaline, Kottarampatel Anwer Hasil, Ourida Manigat France, Silué Navoun, Tchagang Caetanie F, Tomaro Kyle, Campbell-Valois François-Xavier
Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
Microorganisms. 2020 Dec 5;8(12):1933. doi: 10.3390/microorganisms8121933.
spp. are one of the leading causes of infectious diarrheal diseases. They are pathovars that are characterized by the harboring of a large plasmid that encodes most virulence genes, including a type III secretion system (T3SS). The archetypal element of the T3SS is the injectisome, a syringe-like nanomachine composed of approximately 20 proteins, spanning both bacterial membranes and the cell wall, and topped with a needle. Upon contact of the tip of the needle with the plasma membrane, the injectisome secretes its protein substrates into host cells. Some of these substrates act as translocators or effectors whose functions are key to the invasion of the cytosol and the cell-to-cell spread characterizing the lifestyle of spp. Here, we review the structure, assembly, function, and methods to measure the activity of the injectisome with a focus on , but complemented with data from other T3SS if required. We also present the regulatory cascade that controls the expression of T3SS genes in . Finally, we describe the function of translocators and effectors during cell-to-cell spread, particularly during escape from the vacuole, a key element of 's pathogenesis that has yet to reveal all of its secrets.
某些菌属是感染性腹泻疾病的主要病因之一。它们是致病型菌株，其特征是携带一个大型质粒，该质粒编码大多数毒力基因，包括III型分泌系统（T3SS）。T3SS的原型元件是注射体，这是一种类似注射器的纳米机器，由大约20种蛋白质组成，跨越细菌的内外膜和细胞壁，并顶端带有一根针。当针的尖端与质膜接触时，注射体将其蛋白质底物分泌到宿主细胞中。其中一些底物充当转运蛋白或效应蛋白，它们的功能对于入侵细胞质和细胞间传播至关重要，这也是某些菌属生活方式的特征。在此，我们综述注射体的结构、组装、功能以及测量其活性的方法，重点关注特定菌属，但如有需要会补充其他T3SS的数据。我们还介绍了控制特定菌属中T3SS基因表达的调控级联反应。最后，我们描述了转运蛋白和效应蛋白在细胞间传播过程中的功能，特别是在从液泡逃逸过程中的功能，液泡逃逸是特定菌属发病机制中的一个关键因素，其所有秘密尚未完全揭示。
