RRC ID 29062
Author Fajardo M, Schleicher M, Noegel A, Bozzaro S, Killinger S, Heuner K, Hacker J, Steinert M.
Title Calnexin, calreticulin and cytoskeleton-associated proteins modulate uptake and growth of Legionella pneumophila in Dictyostelium discoideum.
Journal Microbiology (Reading, Engl.)
Abstract The haploid amoeba Dictyostelium discoideum is a versatile host system for studying cellular aspects of Legionella pathogenicity. Previous studies have shown that the internalization of L. pneumophila leads to an endoplasmic reticulum (ER)-derived organelle that supports intracellular replication of the bacteria. In this study a roadmap of host-cell factors involved in this process was developed. Phagocytosis assays with specific cellular inhibitors and the effects of well defined host-cell mutants revealed that cytoplasmic calcium levels, cytoskeleton-associated proteins and the calcium-binding proteins of the ER, calreticulin and calnexin, specifically influence the uptake and intracellular growth of L. pneumophila. Confocal microscopic time series with green fluorescent protein (GFP)-tagged calnexin and calreticulin demonstrated the accumulation of both proteins in the phagocytic cup of L. pneumophila-infected host cells. In contrast to the control experiment with Escherichia coli-containing phagosomes, both proteins decorated the replicative vacuole of L. pneumophila during the entire growth phase of the bacteria. The cumulative effects of cytosolic calcium levels, the spatial distribution of calnexin and calreticulin, and the defective invasion and replication of L. pneumophila in calnexin- and calreticulin-minus cells suggest that these factors are part of a regulatory system that leads to the specific vacuole of L. pneumophila.
Volume 150(Pt 9)
Pages 2825-35
Published 2004-9
DOI 10.1099/mic.0.27111-0
PII 150/9/2825
PMID 15347742
MeSH Animals Artificial Gene Fusion Calcium / physiology Calcium-Binding Proteins / physiology Calnexin / genetics Calnexin / physiology* Calreticulin / genetics Calreticulin / physiology* Colony Count, Microbial Cytoplasm / chemistry Cytoskeleton / physiology* Dictyostelium / drug effects Dictyostelium / genetics Dictyostelium / metabolism Dictyostelium / microbiology* Gene Deletion Genes, Reporter Legionella pneumophila / growth & development* Legionella pneumophila / metabolism Legionella pneumophila / pathogenicity Microscopy, Confocal Mutation Phagocytosis / drug effects Protozoan Proteins / physiology Recombinant Fusion Proteins / metabolism Vacuoles / chemistry Vacuoles / microbiology Vacuoles / ultrastructure
IF 1.866
Times Cited 45
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