Yersinia outer protein YopE affects the actin cytoskeleton in Dictyostelium discoideumthrough targeting of multiple Rho family GTPases

Vlahou, Georgia; Schmidt, Oxana; Wagner, Bettina; Uenlue, Handan; Dersch, Petra; Rivero, Francisco; Weissenmayer, Barbara

doi:10.1186/1471-2180-9-138

Cited by 18 publications

(16 citation statements)

References 59 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One key feature of YopE is that this effector inhibits Rho family GTPases via its inherent GAP activity [18,19]. It should be noted that some macrophage anti-bacterial responses induced by YopE have been suggested to be dependent upon its GAP mimetic ability [20].…”

Section: Resultsmentioning

confidence: 99%

The Yersinia pestis Effector YopM Inhibits Pyrin Inflammasome Activation

et al. 2016

View full text Add to dashboard Cite

Type III secretion systems (T3SS) are central virulence factors for many pathogenic Gram-negative bacteria, and secreted T3SS effectors can block key aspects of host cell signaling. To counter this, innate immune responses can also sense some T3SS components to initiate anti-bacterial mechanisms. The Yersinia pestis T3SS is particularly effective and sophisticated in manipulating the production of pro-inflammatory cytokines IL-1β and IL-18, which are typically processed into their mature forms by active caspase-1 following inflammasome formation. Some effectors, like Y. pestis YopM, may block inflammasome activation. Here we show that YopM prevents Y. pestis induced activation of the Pyrin inflammasome induced by the RhoA-inhibiting effector YopE, which is a GTPase activating protein. YopM blocks YopE-induced Pyrin-mediated caspase-1 dependent IL-1β/IL-18 production and cell death. We also detected YopM in a complex with Pyrin and kinases RSK1 and PKN1, putative negative regulators of Pyrin. In contrast to wild-type mice, Pyrin deficient mice were also highly susceptible to an attenuated Y. pestis strain lacking YopM, emphasizing the importance of inhibition of Pyrin in vivo. A complex interplay between the Y. pestis T3SS and IL-1β/IL-18 production is evident, involving at least four inflammasome pathways. The secreted effector YopJ triggers caspase-8- dependent IL-1β activation, even when YopM is present. Additionally, the presence of the T3SS needle/translocon activates NLRP3 and NLRC4-dependent IL-1β generation, which is blocked by YopK, but not by YopM. Taken together, the data suggest YopM specificity for obstructing the Pyrin pathway, as the effector does not appear to block Y. pestis-induced NLRP3, NLRC4 or caspase-8 dependent caspase-1 processing. Thus, we identify Y. pestis YopM as a microbial inhibitor of the Pyrin inflammasome. The fact that so many of the Y. pestis T3SS components are participating in regulation of IL-1β/IL-18 release suggests that these effects are essential for maximal control of innate immunity during plague.

show abstract

Section: Resultsmentioning

confidence: 99%

The Yersinia pestis Effector YopM Inhibits Pyrin Inflammasome Activation

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Many aspects of phagocytosis have been studied in Dictyostelium, such as the dynamics of the actin cytoskeleton, cellular adhesion, phagosome maturation, and intracellular killing (13,33,35). Dictyostelium has also been used to analyze virulence in different bacterial species, including extracellular and intracellular bacteria, such as Pseudomonas (11,42), Yersinia (50), Vibrio (43,44), Legionella (22,25,28), and Mycobacterium (20,41). In addition, host genes required for the killing of a laboratory strain of Klebsiella pneumoniae by phagocytes were also identified with the Dictyostelium model (4).…”

mentioning

confidence: 99%

Use of aDictyosteliumModel for Isolation of Genetic Loci Associated with Phagocytosis and Virulence inKlebsiella pneumoniae

2011

View full text Add to dashboard Cite

Phagocytosis resistance is an important virulence factor in Klebsiella pneumoniae. Dictyostelium has been used to study the interaction between phagocytes and bacteria because of its similarity to mammalian macrophages. In this study, we used a Dictyostelium model to investigate genes for resistance to phagocytosis in NTUH-K2044, a strain of K. pneumoniae causing pyogenic liver abscess that is highly resistant to phagocytosis. A total of 2,500 transposon mutants were screened by plaque assay, and 29 of them permitted phagocytosis by Dictyostelium. In the 29 mutants, six loci were identified; three were capsular synthesis genes. Of the other three, one was related to carnitine metabolism, one encoded a subunit of protease (clpX), and one encoded a lipopolysaccharide O-antigen transporter (wzm). Deletion and complementation of these genes showed that only ⌬clpX and ⌬wzm mutants became susceptible to Dictyostelium phagocytosis, and their complementation restored the phagocytosis resistance phenotype. These two mutants were also susceptible to phagocytosis by human neutrophils and revealed attenuated virulence in a mouse model, implying that they play important roles in the pathogenesis of K. pneumoniae. Furthermore, we demonstrated that clpP, which exists in an operon with clpX, was also involved in resistance to phagocytosis. The transcriptional profile of ⌬clpX was examined by microarray analysis and revealed a 3-fold lower level of expression of capsular synthesis genes. Therefore, we have identified genes involved in resistance to phagocytosis in K. pneumoniae using Dictyostelium, and this model is useful to explore genes associated with resistance to phagocytosis in heavily encapsulated bacteria.Phagocytes are a first line of defense against pathogenic organisms and play a key role in the host's innate immune response to bacterial infection. At the same time, bacteria that have developed resistance to phagocytosis or intracellular killing should be more virulent and more likely to succeed in establishing infection. Recently, a powerful model system involving Dictyostelium discoideum was introduced for studying the interactions between phagocytes and bacteria. The amoebal form of D. discoideum shares many unique traits with human phagocytes, especially the ability to ingest and kill bacteria. In addition, bacteria are thought to use similar mechanisms to resist both Dictyostelium in the environment and human phagocytes; therefore, Dictyostelium provides a useful system to study both cellular response and bacterial virulence. Many aspects of phagocytosis have been studied in Dictyostelium, such as the dynamics of the actin cytoskeleton, cellular adhesion, phagosome maturation, and intracellular killing (13,33,35). Dictyostelium has also been used to analyze virulence in different bacterial species, including extracellular and intracellular bacteria, such as Pseudomonas (11, 42), Yersinia (50), Vibrio (43, 44), Legionella (22,25,28), and Mycobacterium (20, 41). In addition, host genes required for the killing of ...

show abstract

“…YopE was shown to target in vivo a broad range of GTPases including Rac1, CDC42, RhoA, TC10 and RhoG (Aili et al, 2008;Mohammadi and Isberg, 2009;Roppenser et al, 2009;Vlahou et al, 2009). As with ExoS, the membrane localization domain of YopE has also been shown to play a critical role in the determination of its in vivo specificity (Krall et al, 2004;Isaksson et al, 2009;Roppenser et al, 2009).…”

Section: Discussionmentioning

confidence: 97%

High catalytic efficiency and resistance to denaturing in bacterial Rho GTPase-activating proteins

Litvak

Levin‐Klein²,

Avner³

et al. 2011

Biological Chemistry

View full text Add to dashboard Cite

Several major bacterial pathogens use the type III secretion system (TTSS) to deliver virulence factors into host cells. Bacterial Rho GTPase activating proteins (RhoGAPs) comprise a remarkable family of type III secreted toxins that modulate cytoskeletal dynamics and manipulate cellular signaling pathways. We show that the RhoGAP activity of Salmonella SptP and Pseudomonas ExoS toxins is resistant to variations in the concentration of NaCl or MgCl(2), unlike the known salt dependant nature of the activity of some eukaryotic GAPs such as p190, RanGAP and p120GAP. Furthermore, SptP-GAP and ExoS-GAP display full activity after treatment at 80°C or with 6 m urea, which suggests that these protein domains are capable of spontaneous folding into an active state following denaturing such as what might occur upon transit through the TTSS needle. We determined the catalytic activity of bacterial GAPs for Rac1, CDC42 and RhoA GTPases and found that ExoS, in addition to Yersinia YopE and Aeromonas AexT toxins, display higher catalytic efficiencies for Rac1 and CDC42 than the known eukaryotic GAPs, making them the most catalytically efficient RhoGAPs known. This study expands our knowledge of the mechanism of action of GAPs and of the ways bacteria mimic host activities and promote catalysis of eukaryotic signaling proteins.

show abstract

Yersinia outer protein YopE affects the actin cytoskeleton in Dictyostelium discoideumthrough targeting of multiple Rho family GTPases

Cited by 18 publications

References 59 publications

The Yersinia pestis Effector YopM Inhibits Pyrin Inflammasome Activation

The Yersinia pestis Effector YopM Inhibits Pyrin Inflammasome Activation

Use of aDictyosteliumModel for Isolation of Genetic Loci Associated with Phagocytosis and Virulence inKlebsiella pneumoniae

High catalytic efficiency and resistance to denaturing in bacterial Rho GTPase-activating proteins

Contact Info

Product

Resources

About