Characterization of
            <i>Pseudomonas aeruginosa</i>
            Exoenzyme S as a Bifunctional Enzyme in J774A.1 Macrophages

Rocha, Claudia L.; Coburn, Jenifer; Rucks, Elizabeth A.; Olson, Joan C.

doi:10.1128/iai.71.9.5296-5305.2003

Cited by 59 publications

(65 citation statements)

References 41 publications

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“…Professor Eric Pearlman (Case Western Reserve University, Cleveland, OH, USA) kindly provided PAK WT, DexoS, DexoT and DexoY strains. PA103 DexoUDexoT supplemented with pUCP empty vector or containing gene encoding for ExoS WT toxin or mutants (ADPRT À , GAP À and ADPRT À /GAP À ) 31 were kindly provided by Dr Joan C. Olson (West Virginia University, Morgantown, WV, USA). All SA strains used in this study were kindly provided by Dr Tarek Msadek (Institut Pasteur, Paris, France).…”

Section: Methodsmentioning

confidence: 99%

Pseudomonas aeruginosa eradicates Staphylococcus aureus by manipulating the host immunity

et al. 2014

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Young cystic fibrosis (CF) patients' airways are mainly colonized by Staphylococcus aureus, while Pseudomonas aeruginosa predominates in adults. However, the mechanisms behind this infection switch are unclear. Here, we show that levels of type-IIA-secreted phospholipase A2 (sPLA2-IIA, a host enzyme with bactericidal activity) increase in expectorations of CF patients in an age-dependent manner. These levels are sufficient to kill S. aureus, with marginal effects on P. aeruginosa strains. P. aeruginosa laboratory strains and isolates from CF patients induce sPLA2-IIA expression in bronchial epithelial cells from CF patients (these cells are a major source of the enzyme). In an animal model of lung infection, P. aeruginosa induces sPLA2-IIA production that favours S. aureus killing. We suggest that sPLA2-IIA induction by P. aeruginosa contributes to S. aureus eradication in CF airways. Our results indicate that a bacterium can eradicate another bacterium by manipulating the host immunity.

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Section: Methodsmentioning

confidence: 99%

Pseudomonas aeruginosa eradicates Staphylococcus aureus by manipulating the host immunity

et al. 2014

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“…ExoS is a bifunctional toxin containing a GTPase-activating protein (GAP) domain and an ADPribosyltransferase (ADPRT) domain. The amino-terminal GAP activity acts on Rho family GTPases while the carboxylterminal ADPRT activity is directed towards Ras and other host-cell proteins (Fraylick et al, 2001;Goehring et al, 1999;Henriksson et al, 2000Henriksson et al, , 2002Krall et al, 2002;Olson et al, 1999;Rocha et al, 2003;Vincent et al, 1999). As a result of these enzymic activities, intoxication with ExoS is associated with several observable phenotypes, including cytotoxicity and inhibition of bacterial internalization by both phagocytic and non-phagocytic mammalian cells (Cowell et al, 2000;Fleiszig et al, 1997;Frithz-Lindsten et al, 1997;Henriksson et al, 2000;Kaufman et al, 2000;Olson et al, 1997Olson et al, , 1999Pederson & Barbieri, 1998;Vincent et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Interactions between effector proteins of the Pseudomonas aeruginosa type III secretion system do not significantly affect several measures of disease severity in mammals

Shaver

Hauser

2006

Microbiology

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The effector proteins of the type III secretion systems of many bacterial pathogens act in a coordinated manner to subvert host cells and facilitate the development and progression of disease. It is unclear whether interactions between the type-III-secreted proteins of Pseudomonas aeruginosa result in similar effects on the disease process. We have previously characterized the contributions to pathogenesis of the type-III-secreted proteins ExoS, ExoT and ExoU when secreted individually. In this study, we extend our prior work to determine whether these proteins have greater than expected effects on virulence when secreted in combination. In vitro cytotoxicity and anti-internalization activities were not enhanced when effector proteins were secreted in combinations rather than alone. Likewise in a mouse model of pneumonia, bacterial burden in the lungs, dissemination and mortality attributable to ExoS, ExoT and ExoU were not synergistically increased when combinations of these effector proteins were secreted. Because of the absence of an appreciable synergistic increase in virulence when multiple effector proteins were secreted in combination, we conclude that any cooperation between ExoS, ExoT and ExoU does not translate into a synergistically significant enhancement of disease severity as measured by these assays. INTRODUCTIONAn emerging theme in bacterial type III secretion is that the multiple effector proteins transported by these systems cooperate to subvert specific host-cell processes, resulting in enhanced virulence. Each factor alone has a minor effect on the overall virulence process, but together they cooperate to dramatically enhance virulence. Often, individual effector proteins target different points within a single host-cell pathway to facilitate an essential step in pathogenesis. For example YopE, YopH, YopT and YopO, four type III effector proteins of Yersinia, impede neutrophil and macrophage phagocytosis by targeting the actin cytoskeleton of these cells in a coordinated manner (Cornelis, 2002). The net result is that Yersinia bacteria are able to persist in the presence of a robust host immune response. Similar cooperation occurs between Salmonella type III effector proteins to orchestrate bacterial entry into intestinal epithelial cells, an essential step in the development of enteritis. A large number of type III effector proteins working in concert are required to achieve maximal levels of Salmonella bacterial uptake (Raffatellu et al., 2005). These proteins cause a complex series of actin cytoskeletal changes, which result in the transient formation of localized host-cell surface membrane ruffles that engulf the invading bacteria. SopB, SopE and SopE2 activate the Rho family GTPases Cdc42 and Rac1, thereby facilitating actin recruitment and polymerization at the site of bacterial entry (Hardt et al., 1998;Zhou et al., 2001). Two other effector proteins, SipA and SipC, further enhance actin nucleation, polymerization and cross-linking by directly binding to actin (Zhou et al., 1999a,b). O...

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“…Type III-delivered ExoS(⌬MLD) stimulates cell death but does not associate with the endoplasmic region yet ADP-ribosylates Ras, uncoupling the ADP-ribosylation of Ras from cytotoxicity (31). Recently, the ADP-ribosylation activity of ExoS has been linked to cellular adherence, the maintenance of filopodia, and enhanced lamellipodia and cellular ruffling (32). Different cell lines demonstrate different sensitivities to intoxication, with epithelial cells being the most affected by the action of ExoS (33).…”

mentioning

confidence: 99%

Ezrin/Radixin/Moesin Proteins Are High Affinity Targets for ADP-ribosylation by Pseudomonas aeruginosa ExoS

Maresso

Baldwin

Barbieri

2004

Journal of Biological Chemistry

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Pseudomonas aeruginosa ExoS is a bifunctional type III-secreted cytotoxin. The N terminus (amino acids 96 -233) encodes a GTPase-activating protein activity, whereas the C terminus (amino acids 234 -453) encodes a factor-activating ExoS-dependent ADP-ribosyltransferase activity. The GTPase-activating protein activity inactivates the Rho GTPases Rho, Rac, and Cdc42 in cultured cells and in vitro, whereas the ADP-ribosylation by ExoS is poly-substrate-specific and includes Ras as an early target for ADP-ribosylation. Infection of HeLa cells with P. aeruginosa producing a GTPase-activating protein-deficient form of ExoS rounded cells, indicating the ADP-ribosyltransferase domain alone is sufficient to elicit cytoskeletal changes. Examination of substrates modified by type III-delivered ExoS identified a 70-kDa protein as an early and predominant target for ADP-ribosylation. Matrix-assisted laser desorption ionization mass spectroscopy identified this protein as moesin, a member of the ezrin/radixin/moesin (ERM) family of proteins. ExoS ADP-ribosylated recombinant moesin at a linear velocity that was 5-fold faster and with a K m that was 2 orders of magnitude lower than Ras. Moesin homologs ezrin and radixin were also ADPribosylated, indicating the ERMs collectively represent high affinity targets of ExoS. Type III delivered ExoS ADP-ribosylated moesin and ezrin (and/or radixin) in cultured HeLa cells. The ERM proteins contribute to cytoskeleton dynamics, and the ability of ExoS to ADPribosylate the ERM proteins links ADP-ribosylation with the cytoskeletal changes associated with ExoS intoxication.

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Characterization of Pseudomonas aeruginosa Exoenzyme S as a Bifunctional Enzyme in J774A.1 Macrophages

Cited by 59 publications

References 41 publications

Pseudomonas aeruginosa eradicates Staphylococcus aureus by manipulating the host immunity

Pseudomonas aeruginosa eradicates Staphylococcus aureus by manipulating the host immunity

Interactions between effector proteins of the Pseudomonas aeruginosa type III secretion system do not significantly affect several measures of disease severity in mammals

Ezrin/Radixin/Moesin Proteins Are High Affinity Targets for ADP-ribosylation by Pseudomonas aeruginosa ExoS

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