Pseudomonas aeruginosa Exoenzyme S Disrupts Ras-mediated Signal Transduction by Inhibiting Guanine Nucleotide Exchange Factor-catalyzed Nucleotide Exchange

Ganesan, Anand K.; Vincent, Timothy S.; Olson, Joan C.; Barbieri, Joseph T.

doi:10.1074/jbc.274.31.21823

Cited by 81 publications

(88 citation statements)

References 40 publications

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“…In vitro, ExoS ADPribosylates several host proteins, including intracellular proteins such as the intermediate filament protein vimentin (Coburn et al, 1989a), several low-molecularmass GTP-binding proteins (Coburn et al, 1989b) and extracellular proteins such as human immunoglobulin 3 and apolipoprotein A1 (Knight & Barbieri, 1997). In vivo, ExoS has been shown to specifically ADPribosylate Ras proteins, uncoupling Ras-mediated signal-transduction pathways , McGuffie et al, 1998Ganesan et al, 1998Ganesan et al, , 1999. Among the four Ras proteins (H-Ras, N-Ras, K-RasA and K-RasB), H-Ras was found to be ADP-ribosylated most extensively.…”

Section: Discussionmentioning

confidence: 99%

Pseudomonas aeruginosa mediated apoptosis requires the ADP-ribosylating activity of ExoS

et al. 2000

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Pseudomonas aeruginosa is an opportunistic bacterial pathogen that primarily infects immunocompromised individuals and patients with cystic fibrosis. Using a tissue culture system, invasive strains of P. aeruginosa were discovered to induce apoptosis at high frequency in HeLa and other epithelial and fibroblast cell lines. This apoptotic phenotype in the infected cells was determined by several criteria including (i) visual changes in cell morphology, (ii) induction of chromatin condensation and nuclear marginalization, (iii) the presence of a high percentage of cells with subG1 DNA content, and (iv) activation of caspase-3 activity. Induction of the type III secretion machinery, but not invasion of P. aeruginosa is required for induction of apoptosis. The apoptosis phenotype is independent of the cytoskeletal rearrangements that occur in the host cell early after infection. Mutants in P. aeruginosa exoS fail to induce apoptosis and complementation with wild-type exoS restored the apoptosis-inducing capacity, demonstrating that ExoS is the effector molecule. Analysis of exoS activity mutants shows that the ADP-ribosylating capacity of ExoS is essential for inducing the apoptotic pathway.

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Section: Discussionmentioning

confidence: 99%

Pseudomonas aeruginosa mediated apoptosis requires the ADP-ribosylating activity of ExoS

et al. 2000

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“…The ADP-ribosylation of Ras by ExoS is known to interfere with guanine nucleotide exchange factor-catalysed GDP to GTP exchange, the interaction of Ras with its downstream effector, Raf-1, and activation of the MAP-kinase, Erk-2 Ganesan et al, 1999;Henriksson et al, 2000a). In addition, the modification of Ras has been found to correlate with ExoS-dependent inhibition of DNA synthesis (McGuffie et al, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…When internalized by bacterial TTS, ExoS ADPRT activity targets multiple cellular LMMG proteins (McGuffie et al, 1998;Fraylick et al, 2002a, b) and requires a eukaryotic cofactor, 14-3-3, for catalytic activity (Coburn et al, 1991;Fu et al, 1993;Masters et al, 1999;Henriksson et al, 2000b). ADP-ribosylation of cellular targets, Ras and RalA, has been found to interfere with their respective signal transduction pathways Ganesan et al, 1999;Henriksson et al, 2000a;Fraylick et al, 2002b), thereby linking a cellular mechanism to the effects of ExoS on eukaryotic cell function. Recent studies have drawn attention to possible modulatory influences the eukaryotic cell can have on ExoS function.…”

Section: Introductionmentioning

confidence: 99%

Cell line differences in bacterially translocated ExoS ADP-ribosyltransferase substrate specificity

et al. 2003

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Exoenzyme S (ExoS) is an ADP-ribosyltransferase (ADPRT) directly translocated into eukaryotic cells by the type III secretory (TTS) process of Pseudomonas aeruginosa. Comparisons of the functional effects of ExoS on human epithelial and murine fibroblastic cells showed that human epithelial cells exhibited an overall increased sensitivity to the effects of bacterially translocated ExoS on cell proliferation, morphology and re-adherence. ExoS was also found to ADP-ribosylate a greater number of low-molecular-mass G (LMMG) proteins in human epithelial cells, as compared to murine fibroblasts. Examination of the cellular mechanism for differences in ExoS ADPRT substrate modification found that the more restricted pattern of substrate modification in murine fibroblasts was not linked to the efficiency of bacterial adherence nor to the efficiency of ExoS internalization by the TTS process. In exploring the cellular nature of patterns of substrate modification, more extensive substrate modification was detected in human and simian cell lines, while rodent cell lines, including rat, mouse and hamster lines, consistently exhibited the more limited pattern of LMMG protein ADP-ribosylation. Patterns of substrate modification were not altered by cellular transformation and occurred independently of cell type. These studies suggest that eukaryotic cell properties, as recognized through studies of cells of different animal origins, affect the substrate targeting of ExoS ADPRT activity, and that this in turn can influence the severity of effects of ExoS on host-cell function.

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“…Moesin Is a High Affinity Substrate for ExoS-Iglewski and Kabat (8) ExoS, and the ExoS/Ras interaction has been well characterized (22). Ras ⌬CAAX (Ras⌬C) is a form of Ras with a deletion in the C-terminal four amino acids.…”

Section: Exos Adp-ribosyltransferase Activity Is Sufficient To Inducementioning

confidence: 99%

“…ExoS ADP-ribosylates a diverse group of proteins (being poly-substrate specific), including vimentin (14), IgG (15), Ras, Ras-like GTPases (16 -20) and is auto-ADP-ribosylated (21). ADP-ribosylation inhibits the interaction of Ras and Rap with their cognate guanine exchange factors (22,23). Mutation of Glu-381 reduces ADP-r activity ϳ2000-fold (24).…”

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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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Pseudomonas aeruginosa Exoenzyme S Disrupts Ras-mediated Signal Transduction by Inhibiting Guanine Nucleotide Exchange Factor-catalyzed Nucleotide Exchange

Cited by 81 publications

References 40 publications

Pseudomonas aeruginosa mediated apoptosis requires the ADP-ribosylating activity of ExoS

Pseudomonas aeruginosa mediated apoptosis requires the ADP-ribosylating activity of ExoS

Cell line differences in bacterially translocated ExoS ADP-ribosyltransferase substrate specificity

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

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