The T3SS of Shigella: Expression, Structure, Function, and Role in Vacuole Escape

Microorganisms

Waad Bajunaid¹  Caetanie F. Tchagang¹  François-Xavier Campbell-Valois¹  Nathaline Haidar-Ahmad¹  FranceOurida Manigat¹  Anwer Hasil Kottarampatel¹  Navoun Silué¹  Kyle Tomaro¹ 

[1] Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada;

关键词: Shigella;    type III secretion system (T3SS);    injectisome;    secretion;    transcription regulation;    virulence;   

DOI  :  10.3390/microorganisms8121933

来源: DOAJ

【 摘 要 】

Shigella spp. are one of the leading causes of infectious diarrheal diseases. They are Escherichia coli 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 Shigella spp. Here, we review the structure, assembly, function, and methods to measure the activity of the injectisome with a focus on Shigella, but complemented with data from other T3SS if required. We also present the regulatory cascade that controls the expression of T3SS genes in Shigella. Finally, we describe the function of translocators and effectors during cell-to-cell spread, particularly during escape from the vacuole, a key element of Shigella’s pathogenesis that has yet to reveal all of its secrets.

【 授权许可】

Unknown