Effects of an isogenic Zn‐metalloprotease‐deficien mutant of <i>Legionella pneumophila</i> in a guinea‐pig pneumonia model

Moffat, Jennifer F.; Edelstein, Paul H.; Regula, Donald; Cirillo, Jeffrey D.; Tompkins, Lucy S.

doi:10.1111/j.1365-2958.1994.tb01057.x

Cited by 96 publications

(77 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It degrades host extracellular matrix and immunity proteins, supports Hartmanella vermiformis amoebae and guinea pig infection, and is indeed found in the L. pneumophila phagosome (62)(63)(64). Here we showed that the enzyme also regulates lipolytic activities of the pathogen that might contribute to the observed loss of hemolytic activities in a L. pneumophila proA knock-out mutant (65,66).…”

Section: Discussionmentioning

confidence: 99%

Zinc Metalloproteinase ProA Directly Activates Legionella pneumophila PlaC Glycerophospholipid:cholesterol Acyltransferase

Lang

Rastew

Hermes

et al. 2012

Journal of Biological Chemistry

View full text Add to dashboard Cite

Background: PlaC is a GDSL enzyme and the major GCAT secreted by Legionella pneumophila. Results: The zinc metalloproteinase ProA processes and activates PlaC. Deletion of regions within a disulfide loop increased GCAT activity. Conclusion: Inhibitory disulfide loop reduction/deletion by ProA activates PlaC GCAT. Significance: Here we recognized the postexport GCAT activation mechanism essential for modification of typical eukaryotic sterols.

show abstract

Section: Discussionmentioning

confidence: 99%

Zinc Metalloproteinase ProA Directly Activates Legionella pneumophila PlaC Glycerophospholipid:cholesterol Acyltransferase

Lang

Rastew

Hermes

et al. 2012

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Given this apparent disparity from the rest of the d N /d S results, a more detailed examination was undertaken. The mature protein product of proA is a secreted metalloprotease which has been shown to have broad specificity and cytotoxic activity (Black et al, 1990;Moffat et al, 1994). In the SBT scheme, the fragment of proA that is used to define the allele (reference sequence M31884; positions 1134-1538) corresponds approximately to amino acids 139-276 of the mature protein.…”

Section: Genealogies Inferred From the Data Corroborate Sequence Clusmentioning

confidence: 99%

Clonal population structure of Legionella pneumophila inferred from allelic profiling

Edwards

Fry²,

Harrison³

2008

Microbiology

View full text Add to dashboard Cite

The population structure of Legionella pneumophila was investigated by analysing nucleotide sequences from six loci (flaA, pilE, asd, mip, mompS and proA) of 335 globally distributed isolates from clinical and environmental sources over a 29-year period (1977-2006). Data were obtained from unrelated isolates from Europe (n5270), Japan (n531), Canada (n57), the USA (n524) and Australia (n51). The country of origin of two strains was unknown. Analysis of these isolates indicated significant linkage disequilibrium between the six loci. Application of six sequence-based recombination detection tests did not reveal evidence of recombination, but estimates of rates of recombination and mutation made by a seventh test suggested that recombination could have occurred at a rate similar to, but probably lower than, that of mutation.Genealogies inferred under models with and without recombination were congruent with each other, providing no definitive evidence regarding recombination, and were in agreement with sequence clusters identified by graph methods. Further evidence supporting the distinct nature of two of the three subspecies of L. pneumophila, subsp. fraseri and subsp. pascullei, was also found. The ratios of non-synonymous to synonymous nucleotide polymorphisms for each of the allele sets were examined and revealed that the putative virulence loci mompS and pilE are under diversifying pressure, while the allelic regions of three other loci linked to virulence (flaA, proA and mip) do not appear to be. INTRODUCTIONFollowing the recognition of the aetiological agent of Legionnaires' disease in 1977(McDade et al., 1977, phenotypic and genotypic analyses of Legionella pneumophila have mainly focused on the short-term epidemiology of the bacterium. In this scenario, the aim has been to demonstrate potential environmental sources of infection, thereby allowing timely intervention, in order to prevent further infection. Many such methods have been developed and applied with the purpose of discriminating between epidemiologically unrelated strains of L. pneumophila, particularly those belonging to serogroup (sg) 1 (Edelstein et al., 1986;Fry et al., 1999; Saunders et al., 1990;Schoonmaker et al., 1992;van Ketel et al., 1984).The utility of the multi-locus sequence typing (MLST) approach, in which sequences from five to 10 housekeeping genes are determined, in the identification of major bacterial lineages associated with invasive disease was first described in 1998 (Enright & Spratt, 1998;Maiden et al., 1998). Since then, this robust and portable technique (or variations of it) has been applied to the study of genetic diversity and clonal expansion, and to the long-term epidemiological analysis of microbial populations (see http://pubmlst.org/ and http://www.mlst.net/) (Giske et al., 2006;Paraskevopoulos et al., 2006;Vassileva et al., 2006).Recently, a similar approach, termed sequence-based typing (SBT), developed by members of the European Working Group for Legionella Infections (EWGLI), was applied to the epidemiolo...

show abstract

“…The enzyme hydrolyzes a broad spectrum of protein substrates and confers hemolytic as well as cytolytic activities (47,53). Additionally, ProA has been shown to contribute to bacterial pathogenesis in a guinea pig model of pneumonia (38). Another hemolytic, but not cytotoxic, protein is the L. pneumophila legiolysin Lly, which is also responsible for color production and fluorescence of the bacterium (61).…”

mentioning

confidence: 99%

Cloning and Characterization of the Gene Encoding the Major Cell-Associated Phospholipase A of Legionella pneumophila , plaB , Exhibiting Hemolytic Activity

et al. 2004

View full text Add to dashboard Cite

Legionella pneumophila, the causative agent of Legionnaires' disease, is an intracellular pathogen of amoebae, macrophages, and epithelial cells. The pathology of Legionella infections involves alveolar cell destruction, and several proteins of L. pneumophila are known to contribute to this ability. By screening a genomic library of L. pneumophila, we found an additional L. pneumophila gene, plaB, which coded for a hemolytic activity and contained a lipase consensus motif in its deduced protein sequence. Moreover, Escherichia coli harboring the L. pneumophila plaB gene showed increased activity in releasing fatty acids predominantly from diacylphosphoand lysophospholipids, demonstrating that it encodes a phospholipase A. It has been reported that culture supernatants and cell lysates of L. pneumophila possess phospholipase A activity; however, only the major secreted lysophospholipase A PlaA has been investigated on the molecular level. We therefore generated isogenic L. pneumophila plaB mutants and tested those for hemolysis, lipolytic activities, and intracellular survival in amoebae and macrophages. Compared to wild-type L. pneumophila, the plaB mutant showed reduced hemolysis of human red blood cells and almost completely lost its cell-associated lipolytic activity. We conclude that L. pneumophila plaB is the gene encoding the major cell-associated phospholipase A, possibly contributing to bacterial cytotoxicity due to its hemolytic activity. On the other hand, in view of the fact that the plaB mutant multiplied like the wild type both in U937 macrophages and in Acanthamoeba castellanii amoebae, plaB is not essential for intracellular survival of the pathogen.Legionella pneumophila is an inhabitant of fresh water, where it intracellularly colonizes protozoa (20). When bacteria-laden aerosols are inhaled by humans, L. pneumophila exploits alveolar macrophages and epithelial cells for its multiplication, leading to a severe pneumonia characterized by destruction of alveolar cells (60). The cytopathology of Legionnaires' disease involves several cytotoxic or hemolytic factors produced by L. pneumophila, for example, the zinc metalloprotease ProA, the legiolysin Lly, and several pore-forming toxins, one of which is an RTX (repeats in structural toxin) protein (12,26,31,35,36,47,61). The zinc metalloprotease ProA is the major extracellular protease of L. pneumophila and its export depends on the L. pneumophila type II protein secretion system (28, 37). The enzyme hydrolyzes a broad spectrum of protein substrates and confers hemolytic as well as cytolytic activities (47, 53). Additionally, ProA has been shown to contribute to bacterial pathogenesis in a guinea pig model of pneumonia (38). Another hemolytic, but not cytotoxic, protein is the L. pneumophila legiolysin Lly, which is also responsible for color production and fluorescence of the bacterium (61). Pore-forming activities of L. pneumophila confer contact-dependent hemolytic and cytotoxic activities toward a variety of cells, especially at high bacterial nu...

show abstract

Effects of an isogenic Zn‐metalloprotease‐deficien mutant of Legionella pneumophila in a guinea‐pig pneumonia model

Cited by 96 publications

References 31 publications

Zinc Metalloproteinase ProA Directly Activates Legionella pneumophila PlaC Glycerophospholipid:cholesterol Acyltransferase

Zinc Metalloproteinase ProA Directly Activates Legionella pneumophila PlaC Glycerophospholipid:cholesterol Acyltransferase

Clonal population structure of Legionella pneumophila inferred from allelic profiling

Cloning and Characterization of the Gene Encoding the Major Cell-Associated Phospholipase A of Legionella pneumophila , plaB , Exhibiting Hemolytic Activity

Contact Info

Product

Resources

About