The <i>Yersinia</i> Ser/Thr protein kinase YpkA/YopO directly interacts with the small GTPases RhoA and Rac‐1

Barz, Corinna; Abahji, Thomas N.; Trülzsch, Konrad; Heesemann, Jürgen

doi:10.1016/s0014-5793(00)02045-7

Cited by 105 publications

(83 citation statements)

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“…1) (Juris et al, 2000). Disruption of the actin cytoskeleton by YpkA might be mediated by its ability to interact with the small GTPase RhoA, which plays an important role in actin dynamics within the cell (Barz et al, 2000;Dukuzumuremyi et al, 2000). Although actin can be phosphorylated in vitro (Juris et al, 2000), the in vivo substrate is not clear.…”

Section: Ypkamentioning

confidence: 99%

Yersinia effectors target mammalian signalling pathways

2002

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SummaryAnimals have an immune system to fight off challenges from both viruses and bacteria. The first line of defence is innate immunity, which is composed of cells that engulf pathogens as well as cells that release potent signalling molecules to activate an inflammatory response and the adaptive immune system. Pathogenic bacteria have evolved a set of weapons, or effectors, to ensure survival in the host. Yersinia spp. use a type III secretion system to translocate these effector proteins, called Yops, into the host. This report outlines how Yops thwart the signalling machinery of the host immune system. Introduction Innate immunity and signallingInnate immunity is the first line of defence against bacterial and viral infection (for a review of innate immunity, see Medzhitov and Janeway, 2000). The cells involved in the immune response use a wide variety of signalling cascades to activate processes such as phagocytosis, cytokine production and release and production of reactive oxygen species. In addition to eliminating pathogens, the innate immune system activates the adaptive immune response through the presentation of foreign peptides to T cells.Phagocytosis is an essential component of the innate immune system (May and Machesky, 2001). Rearrangement of the actin cytoskeleton during phagocytosis is mediated by the recruitment of proteins that function in actin rearrangement; these include paxillin, p130Cas and focal adhesion kinase (FAK) (Greenberg et al., 1990;Allen and Aderem, 1996). These proteins may form through M cells (microfold cells), which are specialized cells that take up foreign antigens, in intestinal Peyer's patches (Autenrieth and Firsching, 1996). Recognition of Yersinia by M cells is mediated via b1 integrins on the M-cell plasma membrane and the invasin protein of Yersinia (Marra and Isberg, 1997;Clark et al., 1998). Once Yersinia has penetrated the M cells, it can localize in the lymphoid tissue of its host.The recently sequenced genome of Y. pestis (Parkhill et al., 2001) suggests that many of the genes that Yersinia uses during infection and invasion, including adhesins, secretion systems and insecticidal toxins, have been acquired from other bacteria and viruses. Furthermore, all three pathogenic species of Yersinia harbour an extrachromosomal plasmid of 70 kb that is essential for virulence (Portnoy and Martinez, 1985). This plasmid contains the genes of a type III secretion system, a translocation apparatus highly conserved among pathogenic Gram-negative bacteria (for a review, see Cornelis, 1998). This secretion system is responsible for the translocation of the Yersinia effectors, termed Yops, into the host cell. Once inside the host cell, Yops carry out disruption of signalling cascades that activate the processes of phagocytosis, cytokine release and respiratory burst. Six Yop effectors have been identified (YopH, YopE, YopJ/P, YpkA/YopO, YopT and YopM). Some of these effectors are known to function in the downregulation of critical signalling cascades of the immune system (Fig...

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Section: Ypkamentioning

confidence: 99%

Yersinia effectors target mammalian signalling pathways

2002

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“…The serine/threonine kinase YopO/YpkA binds to actin, which promotes autophosphorylation (10). YopO/YpkA furthermore interacts with RhoA and Rac, which may lead to inactivation of these molecules (11,12). YopH is a tyrosine phosphatase that exerts its effects by dephosphorylating host cell proteins, such as p130Cas and the focal adhesion kinase (13,14).…”

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The Proteasome Pathway Destabilizes Yersinia Outer Protein E and Represses Its Antihost Cell Activities

Ruckdeschel

Pfaffinger

Trülzsch

et al. 2006

The Journal of Immunology

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Pathogenic Yersinia spp. neutralize host defense mechanisms by engaging a type III protein secretion system that translocates several Yersinia outer proteins (Yops) into the host cell. Although the modulation of the cellular responses by individual Yops has been intensively studied, little is known about the fate of the translocated Yops inside the cell. In this study, we investigated involvement of the proteasome, the major nonlysosomal proteolytic system in eukaryotic cells, in Yop destabilization and repression. Our data show that inhibition of the proteasome in Yersinia enterocolitica-infected cells selectively stabilized the level of YopE, but not of YopH or YopP. In addition, YopE was found to be modified by ubiquitination. This suggests that the cytotoxin YopE is physiologically subjected to degradation via the ubiquitin-proteasome pathway inside the host cell. Importantly, the increased levels of YopE upon proteasome inhibition were associated with decreased activity of its cellular target Rac. Thus, the GTPase-down-regulating function of YopE is enhanced when the proteasome is inhibited. The stabilization of YopE by proteasome inhibitor treatment furthermore led to aggravation of the cytotoxic YopE effects on the actin cytoskeleton and on host cell morphology. Together, these data show that the host cell proteasome functions to destabilize and inactivate the Yersinia effector protein YopE. This implies the proteasome as integral part of the cellular host immune response against the immunomodulatory activities of a translocated bacterial virulence protein.

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“…The cellular targets of some Yops are known. For example, YopH is a potent tyrosine phosphatase that dephosphorylates macrophage p130Cas and focal adhesion kinase proteins and disrupts focal adhesions (5-7), YopE is a GTPase-activating protein that causes actin cytoskeleton depolymerization (8), and YpkA is a Ser/Thr kinase that interferes with Rho-mediated cellular signaling (9). Recent data suggest that YopM targets the cellular kinases protein kinase C-like 2 and ribosomal S6 protein kinase 1 (10).…”

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Novel Protein-Protein Interactions of the Yersinia pestis Type III Secretion System Elucidated with a Matrix Analysis by Surface Plasmon Resonance and Mass Spectrometry

Świętnicki

O’Brien

Holman

et al. 2004

Journal of Biological Chemistry

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Binary complexes formed by components of theYopB and YopD, in conjunction with LcrV, are thought to form a pore in the membrane of mammalian cells through which the Yops (3, 4) are delivered. The cellular targets of some Yops are known. For example, YopH is a potent tyrosine phosphatase that dephosphorylates macrophage p130Cas and focal adhesion kinase proteins and disrupts focal adhesions (5-7), YopE is a GTPase-activating protein that causes actin cytoskeleton depolymerization (8), and YpkA is a Ser/Thr kinase that interferes with Rho-mediated cellular signaling (9). Recent data suggest that YopM targets the cellular kinases protein kinase C-like 2 and ribosomal S6 protein kinase 1 (10). Transport of YopB, YopD, YopE, YopH, and YopT through the injectosome (11-13) is facilitated by formation of a complex between the secreted protein and a specific Yop chaperone (Syc) also encoded by pCD1. The three other effectors, YopJ, YopM, and YopO (YpkA), do not appear to require cognate secretion chaperones for transport (13). Comparatively little is known about the transient interactions involved in the assembly of the injectosome, the precise order of assembly and delivery of the bacterial proteins into mammalian cells, and the energy source for the transport. To add to the complexity of the problem, protein-RNA and protein-DNA interactions are postulated for some components of the TTSS (14, 15). Deleting any single component of the TTSS attenuates bacterial virulence, suggesting that the Yops, Sycs, and other accessory proteins assemble into a large multisubunit complex. As an essential component of the coordinately regulated low Ca 2ϩ response stimulon (LCR) of pCD1, LcrF stimulates maximum expression of LcrV and Yops at 37°C, and this activation step requires host cell contact or Ca 2ϩ depletion (16,17).As an approach to study the assembly of the Y. pestis virulence machinery, we used a two-step screening process to identify direct interactions between pairs of TTSS proteins. Protein interactions were first detected by surface plasmon resonance (SPR) and then classified according to the strength of interaction at equilibrium. Positive interactions indicated by SPR were next confirmed by MALDI-TOF mass spectrometry. Our results suggest that the combination of SPR and MALDI-TOF mass spectrometry is a powerful method for rapidly identifying protein-protein interactions involved in complex macromolecular assemblies such as the type III secretion system. MATERIALS AND METHODS Protein Expression and Purification-The open reading frames encoding Y. pestis YopK, LcrG, LcrH, LcrQ, and YmoA were amplified from genomic DNA from Y. pestis biovar Orientalis, strain 195/P, kindly

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The Yersinia Ser/Thr protein kinase YpkA/YopO directly interacts with the small GTPases RhoA and Rac‐1

Cited by 105 publications

References 30 publications

Yersinia effectors target mammalian signalling pathways

Yersinia effectors target mammalian signalling pathways

The Proteasome Pathway Destabilizes Yersinia Outer Protein E and Represses Its Antihost Cell Activities

Novel Protein-Protein Interactions of the Yersinia pestis Type III Secretion System Elucidated with a Matrix Analysis by Surface Plasmon Resonance and Mass Spectrometry

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