Affiliation:
1. Australian Bacterial Pathogenesis Program, Department of Microbiology, Monash University, Victoria 3800, Australia
2. Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois 60611
3. Department of Microbiology and Immunology, University of Melbourne, Victoria 3010, Australia
Abstract
ABSTRACT
The environmental pathogen
Legionella pneumophila
possesses five proteins with Sel1 repeats (SLRs) from the tetratricopeptide repeat protein family. Three of these proteins, LpnE, EnhC, and LidL, have been implicated in the ability of
L. pneumophila
to efficiently establish infection and/or manipulate host cell trafficking events. Previously, we showed that LpnE is important for
L. pneumophila
entry into macrophages and epithelial cells. In further virulence studies here, we show that LpnE is also required for efficient infection of
Acanthamoeba castellanii
by
L. pneumophila
and for replication of
L. pneumophila
in the lungs of A/J mice. In addition, we found that the role of LpnE in host cell invasion is dependent on the eight SLR regions of the protein. A truncated form of LpnE lacking the two C-terminal SLR domains was unable to complement the invasion defect of an
lpnE
mutant of
L. pneumophila
130b in both the A549 and THP-1 cell lines. The
lpnE
mutant displayed impaired avoidance of LAMP-1 association, suggesting that LpnE influenced trafficking of the
L. pneumophila
vacuole, similar to the case for EnhC and LidL. We also found that LpnE was present in
L. pneumophila
culture supernatants and that its export was independent of both the Lsp type II secretion system and the Dot/Icm type IV secretion system. The fact that LpnE was exported suggested that the protein may interact with a eukaryotic protein. Using LpnE as bait, we screened a HeLa cell cDNA library for interacting partners, using the yeast two-hybrid system. Examination of the protein-protein interaction between LpnE and a eukaryotic protein, obscurin-like protein 1, suggested that LpnE can interact with eukaryotic proteins containing immunoglobulin-like folds via the SLR regions. This investigation has further characterized the contribution of LpnE to
L. pneumophila
virulence and, more specifically, the importance of the SLR regions to LpnE function.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Reference57 articles.
1. The phagosome containing Legionella pneumophila within the protozoan Hartmannella vermiformis is surrounded by the rough endoplasmic reticulum
2. Current protocols in molecular biology 1995
3. Bagnato, P., V. Barone, E. Giacomello, D. Rossi, and V. Sorrentino. 2003. Binding of an ankyrin-1 isoform to obscurin suggests a molecular link between the sarcoplasmic reticulum and myofibrils in striated muscles. J. Cell Biol.160:245-253.
4. Bartel, P. L., C.-T. Chien, R. Sternglanz, and S. R. Fields. 1993. Using the two-hybrid system to detect protein-protein interactions, p. 153-179. In D. A. Hartley (ed.), Cellular interactions in development: a cellular approach. Oxford University Press, Oxford, United Kingdom.
5. Beuzon, C. R., and D. W. Holden. 2001. Use of mixed infections with Salmonella strains to study virulence genes and their interactions in vivo. Microbes Infect.3:1345-1352.
Cited by
84 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