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St. Louis BM, Quagliato SM, Lee PC. Bacterial effector kinases and strategies to identify their target host substrates. Front Microbiol 2023; 14:1113021. [PMID: 36846793 PMCID: PMC9950578 DOI: 10.3389/fmicb.2023.1113021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/25/2023] [Indexed: 02/12/2023] Open
Abstract
Post-translational modifications (PTMs) are critical in regulating protein function by altering chemical characteristics of proteins. Phosphorylation is an integral PTM, catalyzed by kinases and reversibly removed by phosphatases, that modulates many cellular processes in response to stimuli in all living organisms. Consequently, bacterial pathogens have evolved to secrete effectors capable of manipulating host phosphorylation pathways as a common infection strategy. Given the importance of protein phosphorylation in infection, recent advances in sequence and structural homology search have significantly expanded the discovery of a multitude of bacterial effectors with kinase activity in pathogenic bacteria. Although challenges exist due to complexity of phosphorylation networks in host cells and transient interactions between kinases and substrates, approaches are continuously being developed and applied to identify bacterial effector kinases and their host substrates. In this review, we illustrate the importance of exploiting phosphorylation in host cells by bacterial pathogens via the action of effector kinases and how these effector kinases contribute to virulence through the manipulation of diverse host signaling pathways. We also highlight recent developments in the identification of bacterial effector kinases and a variety of techniques to characterize kinase-substrate interactions in host cells. Identification of host substrates provides new insights for regulation of host signaling during microbial infection and may serve as foundation for developing interventions to treat infection by blocking the activity of secreted effector kinases.
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Affiliation(s)
- Brendyn M. St. Louis
- Department of Biological Sciences, College of Liberal Arts and Sciences, Wayne State University, Detroit, MI, United States
| | - Sydney M. Quagliato
- Department of Biological Sciences, College of Liberal Arts and Sciences, Wayne State University, Detroit, MI, United States
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Osterloh A. Vaccination against Bacterial Infections: Challenges, Progress, and New Approaches with a Focus on Intracellular Bacteria. Vaccines (Basel) 2022; 10:vaccines10050751. [PMID: 35632507 PMCID: PMC9144739 DOI: 10.3390/vaccines10050751] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/08/2022] [Accepted: 05/09/2022] [Indexed: 12/13/2022] Open
Abstract
Many bacterial infections are major health problems worldwide, and treatment of many of these infectious diseases is becoming increasingly difficult due to the development of antibiotic resistance, which is a major threat. Prophylactic vaccines against these bacterial pathogens are urgently needed. This is also true for bacterial infections that are still neglected, even though they affect a large part of the world’s population, especially under poor hygienic conditions. One example is typhus, a life-threatening disease also known as “war plague” caused by Rickettsia prowazekii, which could potentially come back in a war situation such as the one in Ukraine. However, vaccination against bacterial infections is a challenge. In general, bacteria are much more complex organisms than viruses and as such are more difficult targets. Unlike comparatively simple viruses, bacteria possess a variety of antigens whose immunogenic potential is often unknown, and it is unclear which antigen can elicit a protective and long-lasting immune response. Several vaccines against extracellular bacteria have been developed in the past and are still used successfully today, e.g., vaccines against tetanus, pertussis, and diphtheria. However, while induction of antibody production is usually sufficient for protection against extracellular bacteria, vaccination against intracellular bacteria is much more difficult because effective defense against these pathogens requires T cell-mediated responses, particularly the activation of cytotoxic CD8+ T cells. These responses are usually not efficiently elicited by immunization with non-living whole cell antigens or subunit vaccines, so that other antigen delivery strategies are required. This review provides an overview of existing antibacterial vaccines and novel approaches to vaccination with a focus on immunization against intracellular bacteria.
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Affiliation(s)
- Anke Osterloh
- Department of Infection Immunology, Research Center Borstel, Parkallee 22, 23845 Borstel, Germany
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Abstract
Despite the maintenance of YopP/J alleles throughout the human-pathogenic Yersinia lineage, the benefit of YopP/J-induced phagocyte death for Yersinia pathogenesis in animals is not obvious. To determine how the sequence divergence of YopP/J has impacted Yersinia virulence, we examined protein polymorphisms in this type III secreted effector protein across 17 Yersinia species and tested the consequences of polymorphism in a murine model of subacute systemic yersiniosis. Our evolutionary analysis revealed that codon 177 has been subjected to positive selection; the Yersinia enterocolitica residue had been altered from a leucine to a phenylalanine in nearly all Yersinia pseudotuberculosis and Yersinia pestis strains examined. Despite this change being minor, as both leucine and phenylalanine have hydrophobic side chains, reversion of YopJF177 to the ancestral YopJL177 variant yielded a Y. pseudotuberculosis strain with enhanced cytotoxicity toward macrophages, consistent with previous findings. Surprisingly, expression of YopJF177L in the mildly attenuated ksgA- background rendered the strain completely avirulent in mice. Consistent with this hypothesis that YopJ activity relates indirectly to Yersinia pathogenesis in vivo, ksgA- strains lacking functional YopJ failed to kill macrophages but actually regained virulence in animals. Also, treatment with the antiapoptosis drug suramin prevented YopJ-mediated macrophage cytotoxicity and enhanced Y. pseudotuberculosis virulence in vivo. Our results demonstrate that Yersinia-induced cell death is detrimental for bacterial pathogenesis in this animal model of illness and indicate that positive selection has driven YopJ/P and Yersinia evolution toward diminished cytotoxicity and increased virulence, respectively.
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Sheppe AEF, Santelices J, Czyz DM, Edelmann MJ. Yersinia pseudotuberculosis YopJ Limits Macrophage Response by Downregulating COX-2-Mediated Biosynthesis of PGE2 in a MAPK/ERK-Dependent Manner. Microbiol Spectr 2021; 9:e0049621. [PMID: 34319170 PMCID: PMC8552654 DOI: 10.1128/spectrum.00496-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 06/22/2021] [Indexed: 12/23/2022] Open
Abstract
Prostaglandin E2 (PGE2) is an essential immunomodulatory lipid released by cells in response to infection with many bacteria, yet its function in macrophage-mediated bacterial clearance is poorly understood. Yersinia overall inhibits the inflammatory circuit, but its effect on PGE2 production is unknown. We hypothesized that one of the Yersinia effector proteins is responsible for the inhibition of PGE2 biosynthesis. We identified that yopB-deficient Y. enterocolitica and Y. pseudotuberculosis deficient in the secretion of virulence proteins via a type 3 secretion system (T3SS) failed to inhibit PGE2 biosynthesis in macrophages. Consistently, COX-2-mediated PGE2 biosynthesis is upregulated in cells treated with heat-killed or T3SS-deficient Y. pseudotuberculosis but diminished in the presence of a MAPK/ERK inhibitor. Mutants expressing catalytically inactive YopJ induce similar levels of PGE2 as heat-killed or ΔyopB Y. pseudotuberculosis, reversed by YopJ complementation. Shotgun proteomics discovered host pathways regulated in a YopJ-mediated manner, including pathways regulating PGE2 synthesis and oxidative phosphorylation. Consequently, this study identified that YopJ-mediated inhibition of MAPK signal transduction serves as a mechanism targeting PGE2, an alternative means of inflammasome inhibition by Yersinia. Finally, we showed that EP4 signaling supports macrophage function in clearing intracellular bacteria. In summary, our unique contribution was to determine a bacterial virulence factor that targets COX-2 transcription, thereby enhancing the intracellular survival of yersiniae. Future studies should investigate whether PGE2 or its stable synthetic derivatives could serve as a potential therapeutic molecule to improve the outcomes of specific bacterial infections. Since other pathogens encode YopJ homologs, this mechanism is expected to be present in other infections. IMPORTANCE PGE2 is a critical immunomodulatory lipid, but its role in bacterial infection and pathogen clearance is poorly understood. We previously demonstrated that PGE2 leads to macrophage polarization toward the M1 phenotype and stimulates inflammasome activation in infected macrophages. Finally, we also discovered that PGE2 improved the clearance of Y. enterocolitica. The fact that Y. enterocolitica hampers PGE2 secretion in a type 3 secretion system (T3SS)-dependent manner and because PGE2 appears to assist macrophage in the clearance of this bacterium indicates that targeting of the eicosanoid pathway by Yersinia might be an adaption used to counteract host defenses. Our study identified a mechanism used by Yersinia that obstructs PGE2 biosynthesis in human macrophages. We showed that Y. pseudotuberculosis interferes with PGE2 biosynthesis by using one of its T3SS effectors, YopJ. Specifically, YopJ targets the host COX-2 enzyme responsible for PGE2 biosynthesis, which happens in a MAPK/ER-dependent manner. Moreover, in a shotgun proteomics study, we also discovered other pathways that catalytically active YopJ targets in the infected macrophages. YopJ was revealed to play a role in limiting host LPS responses, including repression of EGR1 and JUN proteins, which control transcriptional activation of proinflammatory cytokine production such as interleukin-1β. Since YopJ has homologs in other bacterial species, there are likely other pathogens that target and inhibit PGE2 biosynthesis. In summary, our study's unique contribution was to determine a bacterial virulence factor that targets COX-2 transcription. Future studies should investigate whether PGE2 or its stable synthetic derivatives could serve as a potential therapeutic target.
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Affiliation(s)
- Austin E. F. Sheppe
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, USA
| | - John Santelices
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, USA
| | - Daniel M. Czyz
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, USA
| | - Mariola J. Edelmann
- Department of Microbiology and Cell Science, College of Agricultural and Life Sciences, University of Florida, Gainesville, Florida, USA
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Tweedie A, Nissan T. Hiding in Plain Sight: Formation and Function of Stress Granules During Microbial Infection of Mammalian Cells. Front Mol Biosci 2021; 8:647884. [PMID: 33996904 PMCID: PMC8116797 DOI: 10.3389/fmolb.2021.647884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/01/2021] [Indexed: 01/21/2023] Open
Abstract
Stress granule (SG) formation is a host cell response to stress-induced translational repression. SGs assemble with RNA-binding proteins and translationally silent mRNA. SGs have been demonstrated to be both inhibitory to viruses, as well as being subverted for viral roles. In contrast, the function of SGs during non-viral microbial infections remains largely unexplored. A handful of microbial infections have been shown to result in host SG assembly. Nevertheless, a large body of evidence suggests SG formation in hosts is a widespread response to microbial infection. Diverse stresses caused by microbes and their products can activate the integrated stress response in order to inhibit translation initiation through phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α). This translational response in other contexts results in SG assembly, suggesting that SG assembly can be a general phenomenon during microbial infection. This review explores evidence for host SG formation in response to bacterial, fungal, and protozoan infection and potential functions of SGs in the host and for adaptations of the pathogen.
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Affiliation(s)
- Alistair Tweedie
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Tracy Nissan
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton, United Kingdom.,Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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Selvaraj C, Vierra M, Dinesh DC, Abhirami R, Singh SK. Structural insights of macromolecules involved in bacteria-induced apoptosis in the pathogenesis of human diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 126:1-38. [PMID: 34090612 DOI: 10.1016/bs.apcsb.2021.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Numbers of pathogenic bacteria can induce apoptosis in human host cells and modulate the cellular pathways responsible for inducing or inhibiting apoptosis. These pathogens are significantly recognized by host proteins and provoke the multitude of several signaling pathways and alter the cellular apoptotic stimuli. This process leads the bacterial entry into the mammalian cells and evokes a variety of responses like phagocytosis, release of mitochondrial cytochrome c, secretion of bacterial effectors, release of both apoptotic and inflammatory cytokines, and the triggering of apoptosis. Several mechanisms are involved in bacteria-induced apoptosis including, initiation of the endogenous death machinery, pore-forming proteins, and secretion of superantigens. Either small molecules or proteins may act as a binding partner responsible for forming the protein complexes and regulate enzymatic activity via protein-protein interactions. The bacteria induce apoptosis, attack the human cell and gain control over various types of cells and tissue. Since these processes are intricate in the defense mechanisms of host organisms against pathogenic bacteria and play an important function in host-pathogen interactions. In this chapter, we focus on the various bacterial-induced apoptosis mechanisms in host cells and discuss the important proteins and bacterial effectors that trigger the host cell apoptosis. The structural characterization of bacterial effector proteins and their interaction with human host cells are also considered.
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Affiliation(s)
- Chandrabose Selvaraj
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
| | - Marisol Vierra
- Department of Pharmacology & Toxicology, Michigan State University, East Lansing, MI, United States
| | | | - Rajaram Abhirami
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India
| | - Sanjeev Kumar Singh
- Computer Aided Drug Design and Molecular Modeling Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi, Tamil Nadu, India.
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Redundant and Cooperative Roles for Yersinia pestis Yop Effectors in the Inhibition of Human Neutrophil Exocytic Responses Revealed by Gain-of-Function Approach. Infect Immun 2020; 88:IAI.00909-19. [PMID: 31871100 DOI: 10.1128/iai.00909-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/16/2019] [Indexed: 12/13/2022] Open
Abstract
Yersinia pestis causes a rapid, lethal disease referred to as plague. Y. pestis actively inhibits the innate immune system to generate a noninflammatory environment during early stages of infection to promote colonization. The ability of Y. pestis to create this early noninflammatory environment is in part due to the action of seven Yop effector proteins that are directly injected into host cells via a type 3 secretion system (T3SS). While each Yop effector interacts with specific host proteins to inhibit their function, several Yop effectors either target the same host protein or inhibit converging signaling pathways, leading to functional redundancy. Previous work established that Y. pestis uses the T3SS to inhibit neutrophil respiratory burst, phagocytosis, and release of inflammatory cytokines. Here, we show that Y. pestis also inhibits release of granules in a T3SS-dependent manner. Moreover, using a gain-of-function approach, we discovered previously hidden contributions of YpkA and YopJ to inhibition and that cooperative actions by multiple Yop effectors are required to effectively inhibit degranulation. Independent from degranulation, we also show that multiple Yop effectors can inhibit synthesis of leukotriene B4 (LTB4), a potent lipid mediator released by neutrophils early during infection to promote inflammation. Together, inhibition of these two arms of the neutrophil response likely contributes to the noninflammatory environment needed for Y. pestis colonization and proliferation.
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Schesser Bartra S, Lorica C, Qian L, Gong X, Bahnan W, Barreras H, Hernandez R, Li Z, Plano GV, Schesser K. Chromosomally-Encoded Yersinia pestis Type III Secretion Effector Proteins Promote Infection in Cells and in Mice. Front Cell Infect Microbiol 2019; 9:23. [PMID: 30854334 PMCID: PMC6396649 DOI: 10.3389/fcimb.2019.00023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 01/22/2019] [Indexed: 11/17/2022] Open
Abstract
Yersinia pestis, the causative agent of plague, possesses a number of virulence mechanisms that allows it to survive and proliferate during its interaction with the host. To discover additional infection-specific Y. pestis factors, a transposon site hybridization (TraSH)-based genome-wide screen was employed to identify genomic regions required for its survival during cellular infection. In addition to several well-characterized infection-specific genes, this screen identified three chromosomal genes (y3397, y3399, and y3400), located in an apparent operon, that promoted successful infection. Each of these genes is predicted to encode a leucine-rich repeat family protein with or without an associated ubiquitin E3 ligase domain. These genes were designated Yersinia leucine-rich repeat gene A (ylrA), B (ylrB), and C (ylrC). Engineered strains with deletions of y3397 (ylrC), y3399 (ylrB), or y3400 (ylrA), exhibited infection defects both in cultured cells and in the mouse. C-terminal FLAG-tagged YlrA, YlrB, and YlrC were secreted by Y. pestis in the absence but not the presence of extracellular calcium and deletions of the DNA sequences encoding the predicted N-terminal type III secretion signals of YlrA, YlrB, and YlrC prevented their secretion, indicating that these proteins are substrates of the type III secretion system (T3SS). Further strengthening the connection with the T3SS, YlrB was readily translocated into HeLa cells and expression of the YlrA and YlrC proteins in yeast inhibited yeast growth, indicating that these proteins may function as anti-host T3S effector proteins.
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Affiliation(s)
- Sara Schesser Bartra
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Cherish Lorica
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States.,Division of Pediatric Infectious Diseases, Department of Pediatrics, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Lianfen Qian
- Department of Mathematics, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Xin Gong
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Wael Bahnan
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Henry Barreras
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Rosmely Hernandez
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Zhongwei Li
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States
| | - Gregory V Plano
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Kurt Schesser
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
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Kamal AHM, Fessler MB, Chowdhury SM. Comparative and network-based proteomic analysis of low dose ethanol- and lipopolysaccharide-induced macrophages. PLoS One 2018; 13:e0193104. [PMID: 29481576 PMCID: PMC5826526 DOI: 10.1371/journal.pone.0193104] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 02/05/2018] [Indexed: 12/24/2022] Open
Abstract
Macrophages are specialized phagocytes that play an essential role in inflammation, immunity, and tissue repair. Profiling the global proteomic response of macrophages to microbial molecules such as bacterial lipopolysaccharide is key to understanding fundamental mechanisms of inflammatory disease. Ethanol is a widely abused substance that has complex effects on inflammation. Reports have indicated that ethanol can activate or inhibit the lipopolysaccharide receptor, Toll-like Receptor 4, in different settings, with important consequences for liver and neurologic inflammation, but the underlying mechanisms are poorly understood. To profile the sequential effect of low dose ethanol and lipopolysaccharide on macrophages, a gel-free proteomic technique was applied to RAW 264.7 macrophages. Five hundred four differentially expressed proteins were identified and quantified with high confidence using ≥ 5 peptide spectral matches. Among these, 319 proteins were shared across all treatment conditions, and 69 proteins were exclusively identified in ethanol-treated or lipopolysaccharide-stimulated cells. The interactive impact of ethanol and lipopolysaccharide on the macrophage proteome was evaluated using bioinformatics tools, enabling identification of differentially responsive proteins, protein interaction networks, disease- and function-based networks, canonical pathways, and upstream regulators. Five candidate protein coding genes (PGM2, ISYNA1, PARP1, and PSAP) were further validated by qRT-PCR that mostly related to glucose metabolism and fatty acid synthesis pathways. Taken together, this study describes for the first time at a systems level the interaction between ethanol and lipopolysaccharide in the proteomic programming of macrophages, and offers new mechanistic insights into the biology that may underlie the impact of ethanol on infectious and inflammatory disease in humans.
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Affiliation(s)
- Abu Hena M. Kamal
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Michael B. Fessler
- Immunity, Inflammation and Disease Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, United States of America
| | - Saiful M. Chowdhury
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, Texas, United States of America
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10
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The eIF2α Kinase Heme-Regulated Inhibitor Protects the Host from Infection by Regulating Intracellular Pathogen Trafficking. Infect Immun 2018; 86:IAI.00707-17. [PMID: 29311243 DOI: 10.1128/iai.00707-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/19/2017] [Indexed: 12/20/2022] Open
Abstract
The host employs both cell-autonomous and system-level responses to limit pathogen replication in the initial stages of infection. Previously, we reported that the eukaryotic initiation factor 2α (eIF2α) kinases heme-regulated inhibitor (HRI) and protein kinase R (PKR) control distinct cellular and immune-related activities in response to diverse bacterial pathogens. Specifically for Listeria monocytogenes, there was reduced translocation of the pathogen to the cytosolic compartment in HRI-deficient cells and consequently reduced loading of pathogen-derived antigens on major histocompatibility complex class I (MHC-I) complexes. Here we show that Hri-/- mice, as well as wild-type mice treated with an HRI inhibitor, are more susceptible to listeriosis. In the first few hours of L. monocytogenes infection, there was much greater pathogen proliferation in the liver of Hri-/- mice than in the liver of Hri+/+ mice. Further, there was a rapid increase of serum interleukin-6 (IL-6) levels in Hri+/+ mice in the first few hours of infection whereas the increase in IL-6 levels in Hri-/- mice was notably delayed. Consistent with these in vivo findings, the rate of listeriolysin O (LLO)-dependent pathogen efflux from infected Hri-/- macrophages and fibroblasts was significantly higher than the rate seen with infected Hri+/+ cells. Treatment of cells with an eIF2α kinase activator enhanced both the HRI-dependent and PKR-dependent infection phenotypes, further indicating the pharmacologically malleability of this signaling pathway. Collectively, these results suggest that HRI mediates the cellular confinement and killing of virulent L. monocytogenes in addition to promoting a system-level cytokine response and that both are required to limit pathogen replication during the first few hours of infection.
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Alugubelly N, Hercik K, Kibler P, Nanduri B, Edelmann MJ. Analysis of differentially expressed proteins in Yersinia enterocolitica-infected HeLa cells. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:562-9. [PMID: 26854600 DOI: 10.1016/j.bbapap.2016.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 01/20/2016] [Accepted: 02/03/2016] [Indexed: 12/22/2022]
Abstract
UNLABELLED Yersinia enterocolitica is a facultative intracellular pathogen and a causative agent of yersiniosis, which can be contracted by ingestion of contaminated food. Yersinia secretes virulence factors to subvert critical pathways in the host cell. In this study we utilized shotgun label-free proteomics to study differential protein expression in epithelial cells infected with Y.enterocolitica. We identified a total of 551 proteins, amongst which 42 were downregulated (including Prostaglandin E Synthase 3, POH-1 and Karyopherin alpha) and 22 were upregulated (including Rab1 and RhoA) in infected cells. We validated some of these results by western blot analysis of proteins extracted from Caco-2 and HeLa cells. The proteomic dataset was used to identify host canonical pathways and molecular functions modulated by this infection in the host cells. This study constitutes a proteome of Yersinia-infected cells and can support new discoveries in the area of host-pathogen interactions. STATEMENT OF SIGNIFICANCE OF THE STUDY We describe a proteome of Yersinia enterocolitica-infected HeLa cells, including a description of specific proteins differentially expressed upon infection, molecular functions as well as pathways altered during infection. This proteomic study can lead to a better understanding of Y. enterocolitica pathogenesis in human epithelial cells.
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Affiliation(s)
- Navatha Alugubelly
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, USA
| | - Kamil Hercik
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, USA
| | - Peter Kibler
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Bindu Nanduri
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, USA
| | - Mariola J Edelmann
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA.
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12
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Grishin AM, Beyrakhova KA, Cygler M. Structural insight into effector proteins of Gram-negative bacterial pathogens that modulate the phosphoproteome of their host. Protein Sci 2015; 24:604-20. [PMID: 25565677 DOI: 10.1002/pro.2636] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 12/29/2014] [Indexed: 12/16/2022]
Abstract
Invading pathogens manipulate cellular process of the host cell to establish a safe replicative niche. To this end they secrete a spectrum of proteins called effectors that modify cellular environment through a variety of mechanisms. One of the most important mechanisms is the manipulation of cellular signaling through modifications of the cellular phosphoproteome. Phosphorylation/dephosphorylation plays a pivotal role in eukaryotic cell signaling, with ∼ 500 different kinases and ∼ 130 phosphatases in the human genome. Pathogens affect the phosphoproteome either directly through the action of bacterial effectors, and/or indirectly through downstream effects of host proteins modified by the effectors. Here we review the current knowledge of the structure, catalytic mechanism and function of bacterial effectors that modify directly the phosphorylation state of host proteins. These effectors belong to four enzyme classes: kinases, phosphatases, phospholyases and serine/threonine acetylases.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5E5
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13
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Plano GV, Schesser K. The Yersinia pestis type III secretion system: expression, assembly and role in the evasion of host defenses. Immunol Res 2014; 57:237-45. [PMID: 24198067 DOI: 10.1007/s12026-013-8454-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Yersinia pestis, the etiologic agent of plague, utilizes a type III secretion system (T3SS) to subvert the defenses of its mammalian hosts. T3SSs are complex nanomachines that allow bacterial pathogens to directly inject effector proteins into eukaryotic cells. The Y. pestis T3SS is not expressed during transit through the flea vector, but T3SS gene expression is rapidly thermoinduced upon entry into a mammalian host. Assembly of the T3S apparatus is a highly coordinated process that requires the homo- and hetero-oligomerization over 20 Yersinia secretion (Ysc) proteins, several assembly intermediates and the T3S process to complete the assembly of the rod and external needle structures. The activation of effector secretion is controlled by the YopN/TyeA/SycN/YscB complex, YscF and LcrG in response to extracellular calcium and/or contact with a eukaryotic cell. Cell contact triggers the T3S process including the secretion and assembly of a pore-forming translocon complex that facilitates the translocation of effector proteins, termed Yersinia outer proteins (Yops), across the eukaryotic membrane. Within the host cell, the Yop effector proteins function to inhibit bacterial phagocytosis and to suppress the production of pro-inflammatory cytokines.
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Affiliation(s)
- Gregory V Plano
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, 1600 NW 10th Avenue, Miami, FL, 33136, USA,
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14
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Grishin AM, Condos TEC, Barber KR, Campbell-Valois FX, Parsot C, Shaw GS, Cygler M. Structural basis for the inhibition of host protein ubiquitination by Shigella effector kinase OspG. Structure 2014; 22:878-88. [PMID: 24856362 DOI: 10.1016/j.str.2014.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/19/2014] [Accepted: 04/09/2014] [Indexed: 11/30/2022]
Abstract
Shigella invasion of its human host is assisted by T3SS-delivered effector proteins. The OspG effector kinase binds ubiquitin and ubiquitin-loaded E2-conjugating enzymes, including UbcH5b and UbcH7, and attenuates the host innate immune NF-kB signaling. We present the structure of OspG bound to the UbcH7∼Ub conjugate. OspG has a minimal kinase fold lacking the activation loop of regulatory kinases. UbcH7∼Ub binds OspG at sites remote from the kinase active site, yet increases its kinase activity. The ubiquitin is positioned in the "open" conformation with respect to UbcH7 using its I44 patch to interact with the C terminus of OspG. UbcH7 binds to OspG using two conserved loops essential for E3 ligase recruitment. The interaction of the UbcH7∼Ub with OspG is remarkably similar to the interaction of an E2∼Ub with a HECT E3 ligase. OspG interferes with the interaction of UbcH7 with the E3 parkin and inhibits the activity of the E3.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Tara E C Condos
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Kathryn R Barber
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | | | - Claude Parsot
- Unité de Pathogénie Microbienne Moléculaire, Institut Pasteur, 75724 Paris, France; INSERM, U786, 75015, Paris, France
| | - Gary S Shaw
- Department of Biochemistry, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, Montreal, QC H3G 1Y6, Canada.
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Grishin AM, Cherney M, Anderson DH, Phanse S, Babu M, Cygler M. NleH defines a new family of bacterial effector kinases. Structure 2013; 22:250-9. [PMID: 24373767 DOI: 10.1016/j.str.2013.11.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 11/04/2013] [Accepted: 11/11/2013] [Indexed: 11/16/2022]
Abstract
Upon host cell infection, pathogenic Escherichia coli hijacks host cellular processes with the help of 20-60 secreted effector proteins that subvert cellular processes to create an environment conducive to bacterial survival. The NleH effector kinases manipulate the NF-κB pathway and prevent apoptosis. They show low sequence similarity to human regulatory kinases and contain two domains, the N-terminal, likely intrinsically unfolded, and a C-terminal kinase-like domain. We show that these effectors autophosphorylate on sites located predominantly in the N-terminal segment. The kinase domain displays a minimal kinase fold, but lacks an activation loop and the GHI subdomain. Nevertheless, all catalytically important residues are conserved. ATP binding proceeds with minimal structural rearrangements. The NleH structure is the first for the bacterial effector kinases family. NleHs and their homologous effector kinases form a new kinase family within the cluster of eukaryotic-like kinases that includes also Rio, Bud32, and KdoK families.
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Affiliation(s)
- Andrey M Grishin
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.
| | - Maia Cherney
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Deborah H Anderson
- Cancer Research, Saskatchewan Cancer Agency, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada
| | - Sadhna Phanse
- Department of Biochemistry, Research and Innovation Centre, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, 3737 Wascana Parkway, Regina, SK S4S 0A2, Canada
| | - Miroslaw Cygler
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada; Department of Biochemistry, McGill University, 3655 Promenade Sir Willam Osler, Montreal, QC H3G 1Y6, Canada.
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Shrestha N, Boucher J, Bahnan W, Clark ES, Rosqvist R, Fields KA, Khan WN, Schesser K. The host-encoded Heme Regulated Inhibitor (HRI) facilitates virulence-associated activities of bacterial pathogens. PLoS One 2013; 8:e68754. [PMID: 23874749 PMCID: PMC3707855 DOI: 10.1371/journal.pone.0068754] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 05/31/2013] [Indexed: 11/18/2022] Open
Abstract
Here we show that cells lacking the heme-regulated inhibitor (HRI) are highly resistant to infection by bacterial pathogens. By examining the infection process in wild-type and HRI null cells, we found that HRI is required for pathogens to execute their virulence-associated cellular activities. Specifically, unlike wild-type cells, HRI null cells infected with the gram-negative bacterial pathogen Yersinia are essentially impervious to the cytoskeleton-damaging effects of the Yop virulence factors. This effect is due to reduced functioning of the Yersinia type 3 secretion (T3S) system which injects virulence factors directly into the host cell cytosol. Reduced T3S activity is also observed in HRI null cells infected with the bacterial pathogen Chlamydia which results in a dramatic reduction in its intracellular proliferation. We go on to show that a HRI-mediated process plays a central role in the cellular infection cycle of the Gram-positive pathogen Listeria. For this pathogen, HRI is required for the post-invasion trafficking of the bacterium to the infected host cytosol. Thus by depriving Listeria of its intracellular niche, there is a highly reduced proliferation of Listeria in HRI null cells. We provide evidence that these infection-associated functions of HRI (an eIF2α kinase) are independent of its activity as a regulator of protein synthesis. This is the first report of a host factor whose absence interferes with the function of T3S secretion and cytosolic access by pathogens and makes HRI an excellent target for inhibitors due to its broad virulence-associated activities.
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Affiliation(s)
- Niraj Shrestha
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Justin Boucher
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Wael Bahnan
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Emily S. Clark
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Roland Rosqvist
- Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Kenneth A. Fields
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Wasif N. Khan
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Kurt Schesser
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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Shrestha N, Bahnan W, Wiley DJ, Barber G, Fields KA, Schesser K. Eukaryotic initiation factor 2 (eIF2) signaling regulates proinflammatory cytokine expression and bacterial invasion. J Biol Chem 2012; 287:28738-44. [PMID: 22761422 DOI: 10.1074/jbc.m112.375915] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
In eukaryotic cells, there are two well characterized pathways that regulate translation initiation in response to stress, and each have been shown to be targeted by various viruses. We recently showed in a yeast-based model that the bacterial virulence factor YopJ disrupts one of these pathways, which is centered on the α-subunit of the translation factor eIF2. Here, we show in mammalian cells that induction of the eIF2 signaling pathway occurs following infection with bacterial pathogens and that, consistent with our yeast-based findings, YopJ reduces eIF2 signaling in response to endoplasmic reticulum stress, heavy metal toxicity, dsRNA, and bacterial infection. We demonstrate that the well documented activities of YopJ, inhibition of NF-κB activation and proinflammatory cytokine expression, are both dependent on an intact eIF2 signaling pathway. Unexpectedly, we found that cells with defective eIF2 signaling were more susceptible to bacterial invasion. This was true for pathogenic Yersinia, a facultative intracellular pathogen, as well as for the intracellular pathogens Listeria monocytogenes and Chlamydia trachomatis. Collectively, our data indicate that the highly conserved eIF2 signaling pathway, which is vitally important for antiviral responses, plays a variety of heretofore unrecognized roles in antibacterial responses.
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Affiliation(s)
- Niraj Shrestha
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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García-Callejo FJ, Minguell-González P, Benavent-Corai V, Santonja-López N, Muñoz-Fernández N, Marco-Algarra J. Amigdalitis por Yersinia enterocolitica. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2011; 62:381-4. [DOI: 10.1016/j.otorri.2011.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 01/28/2011] [Accepted: 01/30/2011] [Indexed: 10/18/2022]
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19
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García-Callejo FJ, Minguell-González P, Benavent-Corai V, Santonja-López N, Muñoz-Fernández N, Marco-Algarra J. Yersinia enterocolitica Tonsillitis. ACTA OTORRINOLARINGOLOGICA ESPANOLA 2011. [DOI: 10.1016/j.otoeng.2011.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Asselin JE, Bonasera JM, Kim JF, Oh CS, Beer SV. Eop1 from a Rubus strain of Erwinia amylovora functions as a host-range limiting factor. PHYTOPATHOLOGY 2011; 101:935-944. [PMID: 21469934 DOI: 10.1094/phyto-12-10-0339] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Strains of Erwinia amylovora, the bacterium causing the disease fire blight of rosaceous plants, are separated into two groups based on host range: Spiraeoideae and Rubus strains. Spiraeoideae strains have wide host ranges, infecting plants in many rosaceous genera, including apple and pear. In the field, Rubus strains infect the genus Rubus exclusively, which includes raspberry and blackberry. Based on comparisons of limited sequence data from a Rubus and a Spiraeoideae strain, the gene eop1 was identified as unusually divergent, and it was selected as a possible host specificity factor. To test this, eop1 genes from a Rubus strain and a Spiraeoideae strain were cloned and mutated. Expression of the Rubus-strain eop1 reduced the virulence of E. amylovora in immature pear fruit and in apple shoots. Sequencing the orfA-eop1 regions of several strains of E. amylovora confirmed that forms of eop1 are conserved among strains with similar host ranges. This work provides evidence that eop1 from a Rubus-specific strain can function as a determinant of host specificity in E. amylovora.
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Affiliation(s)
- J E Asselin
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA
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Staphylococcal PknB as the first prokaryotic representative of the proline-directed kinases. PLoS One 2010; 5:e9057. [PMID: 20140229 PMCID: PMC2816222 DOI: 10.1371/journal.pone.0009057] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 01/18/2010] [Indexed: 01/25/2023] Open
Abstract
In eukaryotic cell types, virtually all cellular processes are under control of proline-directed kinases and especially MAP kinases. Serine/threonine kinases in general were originally considered as a eukaryote-specific enzyme family. However, recent studies have revealed that orthologues of eukaryotic serine/threonine kinases exist in bacteria. Moreover, various pathogenic species, such as Yersinia and Mycobacterium, require serine/threonine kinases for successful invasion of human host cells. The substrates targeted by bacterial serine/threonine kinases have remained largely unknown. Here we report that the serine/threonine kinase PknB from the important pathogen Staphylococcus aureus is released into the external milieu, which opens up the possibility that PknB does not only phosphorylate bacterial proteins but also proteins of the human host. To identify possible human targets of purified PknB, we studied in vitro phosphorylation of peptide microarrays and detected 68 possible human targets for phosphorylation. These results show that PknB is a proline-directed kinase with MAP kinase-like enzymatic activity. As the potential cellular targets for PknB are involved in apoptosis, immune responses, transport, and metabolism, PknB secretion may help the bacterium to evade intracellular killing and facilitate its growth. In apparent agreement with this notion, phosphorylation of the host-cell response coordinating transcription factor ATF-2 by PknB was confirmed by mass spectrometry. Taken together, our results identify PknB as the first prokaryotic representative of the proline-directed kinase/MAP kinase family of enzymes.
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