Type VI Secretion Systems Present New Insights on Pathogenic Yersinia.

Xiaobing Yang,Yao Wang,Xihui Shen,Junfeng Pan

doi:10.3389/fcimb.2018.00260

Abstract

The type VI secretion system (T6SS) is a versatile secretion system widely distributed in Gram-negative bacteria that delivers multiple effector proteins into either prokaryotic or eukaryotic cells, or into the extracellular milieu. T6SS participates in various physiological processes including bacterial competition, host infection, and stress response. Three pathogenic Yersinia species, namely Yersinia pestis, Yersinia pseudotuberculosis, and Yersinia enterocolitica, possess different copies of T6SSs with distinct biological functions. This review summarizes the pathogenic, antibacterial, and stress-resistant roles of T6SS in Yersinia and the ion-transporting ability in Y. pseudotuberculosis. In addition, the T6SS-related effectors and regulators identified in Yersinia are discussed.

Highlights

The genus Yersinia comprises three species of bacterial pathogens, namely Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis, that are causative agents of human diseases
In the Yersinia species, six and four T6SS clusters were identified in Y. pestis (Andersson et al, 2017) and Y. pseudotuberculosis (Zhang et al, 2011b), respectively, while only one copy was found in Y. enterocolitica (Jaakkola et al, 2015)
A similar thermoregulated gene cluster in Y. pseudotuberculosis was identified as T6SS4, which is precisely regulated by temperature, growth phase, and acylated homoserine lactones (AHLs)-dependent quorum sensing systems, and plays a crucial role in resistance to environmental stresses (Zhang et al, 2011b)

Summary

Introduction

The genus Yersinia comprises three species of bacterial pathogens, namely Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis, that are causative agents of human diseases. Various effectors and chaperones could bind to this injection apparatus when they were needed to be secreted out through the T6SS apparatus, and the secretion of Hcp or VgrG is often regarded as the hallmark of a functional T6SS in many bacterial species (Mougous et al, 2006; Pukatzki et al, 2006; Wang et al, 2011).

Results

Conclusion