Scientists at Tufts University, Medical Department detail research in legionnaire disease
March 17th, 2009
2009 MAR 17 -- "The bacterial pathogen Legionella pneumophila replicates in a specialized vacuole within host cells. Establishment of the replication vacuole depends on the Dot/Icm translocation system that delivers a large number of protein substrates into the host cell," investigators in the United States report.
"The functions of most substrates are unknown. Here, we analysed a defined set of 127 confirmed or candidate Dot/Icm substrates for their effect on host cell processes using yeast as a model system. Expression of 79 candidates caused significant yeast growth defects, indicating that these proteins impact essential host cell pathways. Notably, a group of 21 candidates interfered with the trafficking of secretory proteins to the yeast vacuole. Three candidates that caused yeast secretory defects (SetA, Ceg19 and Ceg9) were investigated further. These proteins impinged upon vesicle trafficking at distinct stages and had signals that allowed translocation into host cells by the Dot/Icm system. Ectopically produced SetA, Ceg19 and Ceg9 localized to secretory organelles in mammalian cells, consistent with a role for these proteins in modulating host cell vesicle trafficking. Interestingly, the ability of SetA to cause yeast phenotypes was dependent upon a functional glycosyltransferase domain," wrote M. Heidtman and colleagues, Tufts University, Medical Department.
The researchers concluded: "We hypothesize that SetA may glycosylate a component of the host cell vesicle trafficking machinery during L. pneumophila infection."
Heidtman and colleagues published their study in Cellular Microbiology (Large-scale identification of Legionella pneumophila Dot/Icm substrates that modulate host cell vesicle trafficking pathways. Cellular Microbiology, 2009;11(2):230-248).
For additional information, contact R.R. Isberg, Tufts University, School Medical, Dept. of Molecular Biology & Microbiology, 150 Harrison Avenue, Boston, MA 02111, USA.
The publisher of the journal Cellular Microbiology can be contacted at: Wiley-Blackwell Publishing, Inc., Commerce Place, 350 Main St., Malden 02148, MA, USA.
Keywords: United States, Boston, Legionnaire Disease, Legionella, Legionellosis, Tufts University, Medical Department.
This article was prepared by Health Risk Factor Week editors from staff and other reports. Copyright 2009, Health Risk Factor Week via NewsRx.com.
