Affiliation:
1. Division of Medical Microbiology, Department of Health and Environment, Linköping University, SE-581 85 Linköping,1 and
2. Department of Cell and Molecular Biology, University of Umeå, SE-901 87 Umeå,2 Sweden
Abstract
ABSTRACT
Pathogenic species of the genus
Yersinia
evade the bactericidal functions of phagocytes. This evasion is mediated through their virulence effectors, Yops, which act within target cells. In this study we investigated the effect of
Yersinia pseudotuberculosis
on Ca
2+
signaling in polymorphonuclear neutrophils. The intracellular free calcium concentration in single adherent human neutrophils was monitored during bacterial infection and, in parallel, the encounter between the bacteria and cells was observed. When a plasmid-cured strain was used for infection, adherence of a single bacterium to the cellular surface induced a β
1
integrin-dependent transient increase in the intracellular concentration of free calcium. This was, however, not seen with Yop-expressing wild-type bacteria, which adhered to the cell surface without generating any Ca
2+
signal. Importantly, the overall Ca
2+
homeostasis was not affected by the wild-type strain; the Ca
2+
signal mediated by the G-protein-coupled formyl-methionyl-leucyl-phenylalanine receptor was still functioning. Hence, the blocking effect was restricted to certain receptors and their signaling pathways. The use of different Yop mutant strains revealed that the protein tyrosine phosphatase YopH was responsible for the inhibition. This virulence determinant has previously been implicated in very rapid
Yersinia
-mediated effects on target cells as the key effector in the blockage of phagocytic uptake. The present finding, that
Y. pseudotuberculosis
, via YopH, specifically inhibits a self-induced immediate-early Ca
2+
signal in neutrophils, offers more-detailed information concerning the effectiveness of this virulence effector and implies an effect on Ca
2+
-dependent, downstream signals.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
72 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献