1
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Le LHM, Ying L, Ferrero RL. Nuclear trafficking of bacterial effector proteins. Cell Microbiol 2021; 23:e13320. [PMID: 33600054 DOI: 10.1111/cmi.13320] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 02/06/2023]
Abstract
Bacterial pathogens can subvert host responses by producing effector proteins that directly target the nucleus of eukaryotic cells in animals and plants. Nuclear-targeting proteins are categorised as either: "nucleomodulins," which have epigenetic-modulating activities; or "cyclomodulins," which specifically interfere with the host cell cycle. Bacteria can deliver these effector proteins to eukaryotic cells via a range of strategies. Despite an increasing number of reports describing the effects of bacterial effector proteins on nuclear processes in host cells, the intracellular pathways used by these proteins to traffic to the nucleus have yet to be fully elucidated. This review will describe current knowledge about how nucleomodulins and cyclomodulins enter eukaryotic cells, exploit endocytic pathways and translocate to the nucleus. We will also discuss the secretion of nuclear-targeting proteins or their release in bacterial membrane vesicles and the trafficking pathways employed by each of these forms. Besides their importance for bacterial pathogenesis, some nuclear-targeting proteins have been implicated in the development of chronic diseases and even cancer. A greater understanding of nuclear-targeting proteins and their actions will provide new insights into the pathogenesis of infectious diseases, as well as contribute to advances in the development of novel therapies against bacterial infections and possibly cancer.
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Affiliation(s)
- Lena Hoang My Le
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Le Ying
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Richard L Ferrero
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
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2
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Khan AA, Khan Z. Bacterial nucleomodulins and cancer: An unresolved enigma. Transl Oncol 2021; 14:100922. [PMID: 33137543 PMCID: PMC7644672 DOI: 10.1016/j.tranon.2020.100922] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 01/07/2023] Open
Abstract
Recent studies in microbial pathogenesis have identified several bacterial proteins with the potential to influence host cell nuclei. This field of research is in its infancy, however it is rapidly growing. In particular, the role of bacterial nucleomodulins in animal oncogenesis is an area that requires attention. Earlier research has suggested the role of nucleomodulins in plant tumor development and these findings may provide us with a better understanding of the role of these proteins in human cancer development. This proposition is further supported by previous identification of nucleomodulins present in bacteria that have been associated with cancer development, but their role in human cancer is unclear. In this article, we provide an update on the status of these nucleomodulins and their role in cancer etiology. We collected information about known bacterial nucleomodulins and tried to relate their mechanistic implication with already known plant tumor development model. The present research indicates that bacterial nucleomodulins may be an important target in cancer etiology and knowledge of their role in human oncogenesis may help us to create suitable alternative cancer management strategies.
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Affiliation(s)
- Abdul Arif Khan
- Indian Council of Medical Research-National AIDS Research Institute, Pune, Maharashtra 411026, India.
| | - Zakir Khan
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Davis Bldg. Rm. 2008, 8700 Beverly Blvd. Los Angeles, CA 90048, United States
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3
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Schubert KA, Xu Y, Shao F, Auerbuch V. The Yersinia Type III Secretion System as a Tool for Studying Cytosolic Innate Immune Surveillance. Annu Rev Microbiol 2020; 74:221-245. [PMID: 32660389 DOI: 10.1146/annurev-micro-020518-120221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microbial pathogens have evolved complex mechanisms to interface with host cells in order to evade host defenses and replicate. However, mammalian innate immune receptors detect the presence of molecules unique to the microbial world or sense the activity of virulence factors, activating antimicrobial and inflammatory pathways. We focus on how studies of the major virulence factor of one group of microbial pathogens, the type III secretion system (T3SS) of human pathogenic Yersinia, have shed light on these important innate immune responses. Yersinia are largely extracellular pathogens, yet they insert T3SS cargo into target host cells that modulate the activity of cytosolic innate immune receptors. This review covers both the host pathways that detect the Yersinia T3SS and the effector proteins used by Yersinia to manipulate innate immune signaling.
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Affiliation(s)
- Katherine Andrea Schubert
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California 95064, USA;
| | - Yue Xu
- National Institute of Biological Sciences, Beijing 102206, China
| | - Feng Shao
- National Institute of Biological Sciences, Beijing 102206, China
| | - Victoria Auerbuch
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, California 95064, USA;
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4
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Uğurlu Ö, Barlas FB, Evran S, Timur S. The cell-penetrating YopM protein-functionalized quantum dot-plasmid DNA conjugate as a novel gene delivery vector. Plasmid 2020; 110:102513. [PMID: 32502501 DOI: 10.1016/j.plasmid.2020.102513] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 02/07/2023]
Abstract
Non-viral gene delivery systems have great potential for safe and efficient gene therapy, while inefficient cellular and nuclear uptake remain as the major hurdles. Novel approaches are needed to enhance the transfection efficiency of non-viral vectors. In accordance with this need, the objective of this study was to construct a non-viral vector that could achieve gene delivery without using additional lipid-based transfection agent. We aimed to impart self-delivery property to a non-viral vector by using the cell and nucleus penetrating properties of YopM proteins from the three Yersinia spp. (Y. pestis, Y. enterocolotica and Y. pseudotuberculosis). Plasmid DNA (pDNA) encoding green fluorescent protein (GFP) was labeled with quantum dots (QDs) via peptide-nucleic acid (PNA) recognition site. Recombinant YopM protein was then attached to the conjugate via a second PNA recognition site. The YopM ̶ QDs ̶ pDNA conjugate was transfected into HeLa cells without using additional transfection reagent. All three conjugates produced GFP fluorescence, indicating that the plasmid was successfully delivered to the nucleus. As control, naked pDNA was transfected into the cells by using a commercial transfection reagent. The Y. pseudotuberculosis YopM-functionalized conjugate achieved the highest GFP expression, compared to other two YopM proteins and the transfection reagent. To the best of our knowledge, YopM protein was used for the first time in a non-viral gene delivery vector.
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Affiliation(s)
- Özge Uğurlu
- Department of Biochemistry, Faculty of Science, Ege University, 35100, Bornov, Izmir, Turkey
| | - Fırat Barış Barlas
- Department of Biochemistry, Faculty of Science, Ege University, 35100, Bornov, Izmir, Turkey
| | - Serap Evran
- Department of Biochemistry, Faculty of Science, Ege University, 35100, Bornov, Izmir, Turkey.
| | - Suna Timur
- Department of Biochemistry, Faculty of Science, Ege University, 35100, Bornov, Izmir, Turkey; Central Research Testing and Analysis Laboratory Research and Application Center, Ege University, 35100, Bornova, Izmir, Turkey
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5
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Bacterial Factors Targeting the Nucleus: The Growing Family of Nucleomodulins. Toxins (Basel) 2020; 12:toxins12040220. [PMID: 32244550 PMCID: PMC7232420 DOI: 10.3390/toxins12040220] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/23/2020] [Accepted: 03/29/2020] [Indexed: 12/18/2022] Open
Abstract
Pathogenic bacteria secrete a variety of proteins that manipulate host cell function by targeting components of the plasma membrane, cytosol, or organelles. In the last decade, several studies identified bacterial factors acting within the nucleus on gene expression or other nuclear processes, which has led to the emergence of a new family of effectors called “nucleomodulins”. In human and animal pathogens, Listeria monocytogenes for Gram-positive bacteria and Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, Legionella pneumophila, Shigella flexneri, and Escherichia coli for Gram-negative bacteria, have led to pioneering discoveries. In this review, we present these paradigms and detail various mechanisms and core elements (e.g., DNA, histones, epigenetic regulators, transcription or splicing factors, signaling proteins) targeted by nucleomodulins. We particularly focus on nucleomodulins interacting with epifactors, such as LntA of Listeria and ankyrin repeat- or tandem repeat-containing effectors of Rickettsiales, and nucleomodulins from various bacterial species acting as post-translational modification enzymes. The study of bacterial nucleomodulins not only generates important knowledge about the control of host responses by microbes but also creates new tools to decipher the dynamic regulations that occur in the nucleus. This research also has potential applications in the field of biotechnology. Finally, this raises questions about the epigenetic effects of infectious diseases.
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6
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Zhang L, Chen L, Dong H. Plant Aquaporins in Infection by and Immunity Against Pathogens - A Critical Review. FRONTIERS IN PLANT SCIENCE 2019; 10:632. [PMID: 31191567 PMCID: PMC6546722 DOI: 10.3389/fpls.2019.00632] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/26/2019] [Indexed: 05/18/2023]
Abstract
Plant aquaporins (AQPs) of the plasma membrane intrinsic protein (PIP) family face constant risk of hijack by pathogens aiming to infect plants. PIPs can also be involved in plant immunity against infection. This review will utilize two case studies to discuss biochemical and structural mechanisms that govern the functions of PIPs in the regulation of plant infection and immunity. The first example concerns the interaction between rice Oryza sativa and the bacterial blight pathogen Xanthomonas oryzae pv. oryzae (Xoo). To infect rice, Xoo uses the type III (T3) secretion system to secrete the proteic translocator Hpa1, and Hpa1 subsequently mediates the translocation of T3 effectors secreted by this system. Once shifted from bacteria into rice cells, effectors exert virulent or avirulent effects depending on the susceptibility of the rice varieties. The translocator function of Hpa1 requires cooperation with OsPIP1;3, the rice interactor of Hpa1. This role of OsPIP1;3 is related to regulatory models of effector translocation. The regulatory models have been proposed as, translocon-dependent delivery, translocon-independent pore formation, and effector endocytosis with membrane protein/lipid trafficking. The second case study includes the interaction of Hpa1 with the H2O2 transport channel AtPIP1;4, and the associated consequence for H2O2 signal transduction of immunity pathways in Arabidopsis thaliana, a non-host of Xoo. H2O2 is generated in the apoplast upon induction by a pathogen or microbial pattern. H2O2 from this source translocates quickly into Arabidopsis cells, where it interacts with pathways of intracellular immunity to confer plant resistance against diseases. To expedite H2O2 transport, AtPIP1;4 must adopt a specific conformation in a number of ways, including channel width extension through amino acid interactions and selectivity for H2O2 through amino acid protonation and tautomeric reactions. Both topics will reference relevant studies, conducted on other organisms and AQPs, to highlight possible mechanisms of T3 effector translocation currently under debate, and highlight the structural basis of AtPIP1;4 in H2O2 transport facilitated by gating and trafficking regulation.
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Affiliation(s)
- Liyuan Zhang
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Lei Chen
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
| | - Hansong Dong
- Plant Immunity Research Group, National Key Laboratory of Crop Science, Department of Plant Pathology, Shandong Agricultural University, Tai’an, China
- Plant Immunity Laboratory, Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China
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7
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Norkowski S, Schmidt MA, Rüter C. The species-spanning family of LPX-motif harbouring effector proteins. Cell Microbiol 2018; 20:e12945. [PMID: 30137651 DOI: 10.1111/cmi.12945] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/09/2018] [Accepted: 08/14/2018] [Indexed: 12/13/2022]
Abstract
The delivery of effector proteins into infected eukaryotic cells represents a key virulence feature of many microbial pathogens in order to derail essential cellular processes and effectively counter the host defence system. Although bacterial effectors are truly numerous and exhibit a wide range of biochemical activities, commonalities in terms of protein structure and function shared by many bacterial pathogens exist. Recent progress has shed light on a species-spanning family of bacterial effectors containing an LPX repeat motif as a subtype of the leucine-rich repeat superfamily, partially combined with a novel E3 ubiquitin ligase domain. This review highlights the immunomodulatory effects of LPX effector proteins, with particular emphasis on the exploitation of the host ubiquitin system.
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Affiliation(s)
- Stefanie Norkowski
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - M Alexander Schmidt
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
| | - Christian Rüter
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Münster, Germany
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8
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Tawk C, Sharan M, Eulalio A, Vogel J. A systematic analysis of the RNA-targeting potential of secreted bacterial effector proteins. Sci Rep 2017; 7:9328. [PMID: 28839189 PMCID: PMC5570926 DOI: 10.1038/s41598-017-09527-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 06/27/2017] [Indexed: 12/15/2022] Open
Abstract
Many pathogenic bacteria utilize specialized secretion systems to deliver proteins called effectors into eukaryotic cells for manipulation of host pathways. The vast majority of known effector targets are host proteins, whereas a potential targeting of host nucleic acids remains little explored. There is only one family of effectors known to target DNA directly, and effectors binding host RNA are unknown. Here, we take a two-pronged approach to search for RNA-binding effectors, combining biocomputational prediction of RNA-binding domains (RBDs) in a newly assembled comprehensive dataset of bacterial secreted proteins, and experimental screening for RNA binding in mammalian cells. Only a small subset of effectors were predicted to carry an RBD, indicating that if RNA targeting was common, it would likely involve new types of RBDs. Our experimental evaluation of effectors with predicted RBDs further argues for a general paucity of RNA binding activities amongst bacterial effectors. We obtained evidence that PipB2 and Lpg2844, effector proteins of Salmonella and Legionella species, respectively, may harbor novel biochemical activities. Our study presenting the first systematic evaluation of the RNA-targeting potential of bacterial effectors offers a basis for discussion of whether or not host RNA is a prominent target of secreted bacterial proteins.
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Affiliation(s)
- Caroline Tawk
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Malvika Sharan
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Ana Eulalio
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany.
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany.
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9
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10
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Gallego-Paez LM, Bordone MC, Leote AC, Saraiva-Agostinho N, Ascensão-Ferreira M, Barbosa-Morais NL. Alternative splicing: the pledge, the turn, and the prestige : The key role of alternative splicing in human biological systems. Hum Genet 2017; 136:1015-1042. [PMID: 28374191 PMCID: PMC5602094 DOI: 10.1007/s00439-017-1790-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/25/2017] [Indexed: 02/06/2023]
Abstract
Alternative pre-mRNA splicing is a tightly controlled process conducted by the spliceosome, with the assistance of several regulators, resulting in the expression of different transcript isoforms from the same gene and increasing both transcriptome and proteome complexity. The differences between alternative isoforms may be subtle but enough to change the function or localization of the translated proteins. A fine control of the isoform balance is, therefore, needed throughout developmental stages and adult tissues or physiological conditions and it does not come as a surprise that several diseases are caused by its deregulation. In this review, we aim to bring the splicing machinery on stage and raise the curtain on its mechanisms and regulation throughout several systems and tissues of the human body, from neurodevelopment to the interactions with the human microbiome. We discuss, on one hand, the essential role of alternative splicing in assuring tissue function, diversity, and swiftness of response in these systems or tissues, and on the other hand, what goes wrong when its regulatory mechanisms fail. We also focus on the possibilities that splicing modulation therapies open for the future of personalized medicine, along with the leading techniques in this field. The final act of the spliceosome, however, is yet to be fully revealed, as more knowledge is needed regarding the complex regulatory network that coordinates alternative splicing and how its dysfunction leads to disease.
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Affiliation(s)
- L M Gallego-Paez
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M C Bordone
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - A C Leote
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N Saraiva-Agostinho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M Ascensão-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N L Barbosa-Morais
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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11
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Grabowski B, Schmidt MA, Rüter C. Immunomodulatory Yersinia outer proteins (Yops)-useful tools for bacteria and humans alike. Virulence 2017; 8:1124-1147. [PMID: 28296562 DOI: 10.1080/21505594.2017.1303588] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human-pathogenic Yersinia produce plasmid-encoded Yersinia outer proteins (Yops), which are necessary to down-regulate anti-bacterial responses that constrict bacterial survival in the host. These Yops are effectively translocated directly from the bacterial into the target cell cytosol by the type III secretion system (T3SS). Cell-penetrating peptides (CPPs) in contrast are characterized by their ability to autonomously cross cell membranes and to transport cargo - independent of additional translocation systems. The recent discovery of bacterial cell-penetrating effector proteins (CPEs) - with the prototype being the T3SS effector protein YopM - established a new class of autonomously translocating immunomodulatory proteins. CPEs represent a vast source of potential self-delivering, anti-inflammatory therapeutics. In this review, we give an update on the characteristic features of the plasmid-encoded Yops and, based on recent findings, propose the further development of these proteins for potential therapeutic applications as natural or artificial cell-penetrating forms of Yops might be of value as bacteria-derived biologics.
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Affiliation(s)
- Benjamin Grabowski
- a Institute of Infectiology - Centre for Molecular Biology of Inflammation (ZMBE), University of Münster , Münster , Germany
| | - M Alexander Schmidt
- a Institute of Infectiology - Centre for Molecular Biology of Inflammation (ZMBE), University of Münster , Münster , Germany
| | - Christian Rüter
- a Institute of Infectiology - Centre for Molecular Biology of Inflammation (ZMBE), University of Münster , Münster , Germany
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12
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The Yersinia Type III secretion effector YopM Is an E3 ubiquitin ligase that induced necrotic cell death by targeting NLRP3. Cell Death Dis 2016; 7:e2519. [PMID: 27929533 PMCID: PMC5260993 DOI: 10.1038/cddis.2016.413] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 12/28/2022]
Abstract
Yersinia pestis uses type III effector proteins to target eukaryotic signaling systems. The Yersinia outer protein (Yop) M effector from the Y. pestis strain is a critical virulence determinant; however, its role in Y. pestis pathogenesis is just beginning to emerge. Here we first identify YopM as the structural mimic of the bacterial IpaH E3 ligase family in vitro, and establish that the conserved CLD motif in its N-terminal is responsible for the E3 ligase function. Furthermore, we show that NLRP3 is a novel target of the YopM protein. Specially, YopM associates with NLRP3, and its CLD ligase motif mediates the activating K63-linked ubiquitylation of NLRP3; as a result, YopM modulates NLRP3-mediated cell necrosis. Mutation of YopM E3 ligase motif dramatically reduces the ability of Y. pestis to induce HMGB1 release and cell necrosis, which ultimately contributes to bacterial virulence. In conclusion, this study has identified a previously unrecognized role for YopM E3 ligase activity in the regulation of host cell necrosis and plague pathogenesis.
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13
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Distribution and Evolution of Yersinia Leucine-Rich Repeat Proteins. Infect Immun 2016; 84:2243-2254. [PMID: 27217422 DOI: 10.1128/iai.00324-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/17/2016] [Indexed: 01/30/2023] Open
Abstract
Leucine-rich repeat (LRR) proteins are widely distributed in bacteria, playing important roles in various protein-protein interaction processes. In Yersinia, the well-characterized type III secreted effector YopM also belongs to the LRR protein family and is encoded by virulence plasmids. However, little has been known about other LRR members encoded by Yersinia genomes or their evolution. In this study, the Yersinia LRR proteins were comprehensively screened, categorized, and compared. The LRR proteins encoded by chromosomes (LRR1 proteins) appeared to be more similar to each other and different from those encoded by plasmids (LRR2 proteins) with regard to repeat-unit length, amino acid composition profile, and gene expression regulation circuits. LRR1 proteins were also different from LRR2 proteins in that the LRR1 proteins contained an E3 ligase domain (NEL domain) in the C-terminal region or an NEL domain-encoding nucleotide relic in flanking genomic sequences. The LRR1 protein-encoding genes (LRR1 genes) varied dramatically and were categorized into 4 subgroups (a to d), with the LRR1a to -c genes evolving from the same ancestor and LRR1d genes evolving from another ancestor. The consensus and ancestor repeat-unit sequences were inferred for different LRR1 protein subgroups by use of a maximum parsimony modeling strategy. Structural modeling disclosed very similar repeat-unit structures between LRR1 and LRR2 proteins despite the different unit lengths and amino acid compositions. Structural constraints may serve as the driving force to explain the observed mutations in the LRR regions. This study suggests that there may be functional variation and lays the foundation for future experiments investigating the functions of the chromosomally encoded LRR proteins of Yersinia.
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Abstract
The human pathogens
Yersinia pseudotuberculosis and
Yersinia enterocolitica cause enterocolitis, while
Yersinia pestis is responsible for pneumonic, bubonic, and septicaemic plague. All three share an infection strategy that relies on a virulence factor arsenal to enable them to enter, adhere to, and colonise the host while evading host defences to avoid untimely clearance. Their arsenal includes a number of adhesins that allow the invading pathogens to establish a foothold in the host and to adhere to specific tissues later during infection. When the host innate immune system has been activated, all three pathogens produce a structure analogous to a hypodermic needle. In conjunction with the translocon, which forms a pore in the host membrane, the channel that is formed enables the transfer of six ‘effector’ proteins into the host cell cytoplasm. These proteins mimic host cell proteins but are more efficient than their native counterparts at modifying the host cell cytoskeleton, triggering the host cell suicide response. Such a sophisticated arsenal ensures that yersiniae maintain the upper hand despite the best efforts of the host to counteract the infecting pathogen.
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Affiliation(s)
- Steve Atkinson
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Paul Williams
- Centre for Biomolecular Sciences, School of Life Sciences, University of Nottingham, Nottingham, UK
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15
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Berneking L, Schnapp M, Rumm A, Trasak C, Ruckdeschel K, Alawi M, Grundhoff A, Kikhney AG, Koch-Nolte F, Buck F, Perbandt M, Betzel C, Svergun DI, Hentschke M, Aepfelbacher M. Immunosuppressive Yersinia Effector YopM Binds DEAD Box Helicase DDX3 to Control Ribosomal S6 Kinase in the Nucleus of Host Cells. PLoS Pathog 2016; 12:e1005660. [PMID: 27300509 PMCID: PMC4907486 DOI: 10.1371/journal.ppat.1005660] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/05/2016] [Indexed: 02/07/2023] Open
Abstract
Yersinia outer protein M (YopM) is a crucial immunosuppressive effector of the plaque agent Yersinia pestis and other pathogenic Yersinia species. YopM enters the nucleus of host cells but neither the mechanisms governing its nucleocytoplasmic shuttling nor its intranuclear activities are known. Here we identify the DEAD-box helicase 3 (DDX3) as a novel interaction partner of Y. enterocolitica YopM and present the three-dimensional structure of a YopM:DDX3 complex. Knockdown of DDX3 or inhibition of the exportin chromosomal maintenance 1 (CRM1) increased the nuclear level of YopM suggesting that YopM exploits DDX3 to exit the nucleus via the CRM1 export pathway. Increased nuclear YopM levels caused enhanced phosphorylation of Ribosomal S6 Kinase 1 (RSK1) in the nucleus. In Y. enterocolitica infected primary human macrophages YopM increased the level of Interleukin-10 (IL-10) mRNA and this effect required interaction of YopM with RSK and was enhanced by blocking YopM's nuclear export. We propose that the DDX3/CRM1 mediated nucleocytoplasmic shuttling of YopM determines the extent of phosphorylation of RSK in the nucleus to control transcription of immunosuppressive cytokines.
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Affiliation(s)
- Laura Berneking
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Marie Schnapp
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Andreas Rumm
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Claudia Trasak
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Klaus Ruckdeschel
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Malik Alawi
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Heinrich-Pette-Institute (HPI), Leibniz Institute for Experimental Virology, Research Group Virus Genomics, Hamburg, Germany
| | - Adam Grundhoff
- Heinrich-Pette-Institute (HPI), Leibniz Institute for Experimental Virology, Research Group Virus Genomics, Hamburg, Germany
| | - Alexey G. Kikhney
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, Hamburg, Germany
| | | | - Friedrich Buck
- Institute of Clinical Chemistry, University Medical Center, Hamburg, Germany
| | - Markus Perbandt
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Laboratory of Structural Biology of Infection and Inflammation, Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
| | - Christian Betzel
- Institute of Biochemistry and Molecular Biology, University of Hamburg, Laboratory of Structural Biology of Infection and Inflammation, Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Outstation, Hamburg, Germany
| | - Moritz Hentschke
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Martin Aepfelbacher
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
- * E-mail:
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16
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Kim JM, Choe MH, Asaithambi K, Song JY, Lee YS, Lee JC, Seo JH, Kang HL, Lee KH, Lee WK, Cho MJ, Rhee KH, Youn HS, Baik SC. Helicobacter pylori HP0425 Targets the Nucleus with DNase I-Like Activity. Helicobacter 2016; 21:218-25. [PMID: 26395879 DOI: 10.1111/hel.12271] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND AND AIMS Nuclear targeting of bacterial proteins has a significant impact on host cell pathology. Helicobacter pylori have many nuclear targeting proteins that translocate into the nucleus of host cells. H. pylori HP0425, annotated as hypothetical, has a nuclear localization signal (NLS) sequence, but its function has not been demonstrated. The aim of this experiment was to address the nuclear translocation of HP0425 and determine the effect of HP0425 pathology on host cells. MATERIALS AND METHODS To investigate the nuclear localization of HP0425, it was expressed in AGS and MKN-1 cells as a GFP fusion protein (pEGFP-HP0425), and its localization was analyzed by confocal microscopy. Recombinant HP0425 (rHP0425) protein was overproduced as a GST fusion protein in Escherichia coli and purified by glutathione-affinity column chromatography. Purified rHP0425 was examined for cytotoxicity and DNase activity. RESULTS The pEGFP-HP0425 fluorescence was expressed in the nucleus and cytosol fraction of cells, while it was localized in the cytoplasm in the negative control. This protein exhibited DNase activity under various conditions, with the highest DNase activity in the presence of manganese. In addition, the rHP0425 protein efficiently decreased cell viability in a concentration-dependent manner. CONCLUSIONS These results suggest that HP0425 carrying a nuclear localization signal sequence translocates into the nucleus of host cells and degrades genomic DNA by DNase I-like enzymatic activity, which is a new pathogenic strategy of H. pylori in the host.
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Affiliation(s)
- Jung-Min Kim
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Min-Ho Choe
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea
| | | | - Jae-Young Song
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Yong Seok Lee
- Department of Life Science and Biotechnology, College of Natural Sciences, Soonchunhyang University, Asan, Korea
| | - Je Chul Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Ji-Hyun Seo
- Department of Pediatrics, Gyeongsang Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Hyung-Lyun Kang
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Kon Ho Lee
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Woo-Kon Lee
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Myung-Je Cho
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Kwang-Ho Rhee
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
| | - Hee-Shang Youn
- Department of Pediatrics, Gyeongsang Institute of Health Science, Gyeongsang National University School of Medicine, Jinju, Korea
| | - Seung-Chul Baik
- Department of Microbiology, Gyeongsang National University School of Medicine, Jinju, Korea.,Research Institute of Life Science, Gyeongsang National University, Jinju, Korea
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17
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López-Baena FJ, Ruiz-Sainz JE, Rodríguez-Carvajal MA, Vinardell JM. Bacterial Molecular Signals in the Sinorhizobium fredii-Soybean Symbiosis. Int J Mol Sci 2016; 17:E755. [PMID: 27213334 PMCID: PMC4881576 DOI: 10.3390/ijms17050755] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/04/2016] [Accepted: 05/05/2016] [Indexed: 12/20/2022] Open
Abstract
Sinorhizobium (Ensifer) fredii (S. fredii) is a rhizobial species exhibiting a remarkably broad nodulation host-range. Thus, S. fredii is able to effectively nodulate dozens of different legumes, including plants forming determinate nodules, such as the important crops soybean and cowpea, and plants forming indeterminate nodules, such as Glycyrrhiza uralensis and pigeon-pea. This capacity of adaptation to different symbioses makes the study of the molecular signals produced by S. fredii strains of increasing interest since it allows the analysis of their symbiotic role in different types of nodule. In this review, we analyze in depth different S. fredii molecules that act as signals in symbiosis, including nodulation factors, different surface polysaccharides (exopolysaccharides, lipopolysaccharides, cyclic glucans, and K-antigen capsular polysaccharides), and effectors delivered to the interior of the host cells through a symbiotic type 3 secretion system.
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Affiliation(s)
- Francisco J López-Baena
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida de Reina Mercedes, 6, 41012 Sevilla, Spain.
| | - José E Ruiz-Sainz
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida de Reina Mercedes, 6, 41012 Sevilla, Spain.
| | - Miguel A Rodríguez-Carvajal
- Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, Profesor García González, 1, 41012 Sevilla, Spain.
| | - José M Vinardell
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida de Reina Mercedes, 6, 41012 Sevilla, Spain.
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18
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Pha K, Navarro L. Yersinia type III effectors perturb host innate immune responses. World J Biol Chem 2016; 7:1-13. [PMID: 26981193 PMCID: PMC4768113 DOI: 10.4331/wjbc.v7.i1.1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 09/02/2015] [Accepted: 11/04/2015] [Indexed: 02/05/2023] Open
Abstract
The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type III secretion system (T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gram-negative bacteria that share in common a 70 kb virulence plasmid which encodes the T3SS. Translocation of the Yersinia effector proteins (YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia effector proteins and their contribution to Yersinia pathogenesis.
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19
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Popa C, Coll NS, Valls M, Sessa G. Yeast as a Heterologous Model System to Uncover Type III Effector Function. PLoS Pathog 2016; 12:e1005360. [PMID: 26914889 PMCID: PMC4767418 DOI: 10.1371/journal.ppat.1005360] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Type III effectors (T3E) are key virulence proteins that are injected by bacterial pathogens inside the cells of their host to subvert cellular processes and contribute to disease. The budding yeast Saccharomyces cerevisiae represents an important heterologous system for the functional characterisation of T3E proteins in a eukaryotic environment. Importantly, yeast contains eukaryotic processes with low redundancy and are devoid of immunity mechanisms that counteract T3Es and mask their function. Expression in yeast of effectors from both plant and animal pathogens that perturb conserved cellular processes often resulted in robust phenotypes that were exploited to elucidate effector functions, biochemical properties, and host targets. The genetic tractability of yeast and its amenability for high-throughput functional studies contributed to the success of this system that, in recent years, has been used to study over 100 effectors. Here, we provide a critical view on this body of work and describe advantages and limitations inherent to the use of yeast in T3E research. “Favourite” targets of T3Es in yeast are cytoskeleton components and small GTPases of the Rho family. We describe how mitogen-activated protein kinase (MAPK) signalling, vesicle trafficking, membrane structures, and programmed cell death are also often altered by T3Es in yeast and how this reflects their function in the natural host. We describe how effector structure–function studies and analysis of candidate targeted processes or pathways can be carried out in yeast. We critically analyse technologies that have been used in yeast to assign biochemical functions to T3Es, including transcriptomics and proteomics, as well as suppressor, gain-of-function, or synthetic lethality screens. We also describe how yeast can be used to select for molecules that block T3E function in search of new antibacterial drugs with medical applications. Finally, we provide our opinion on the limitations of S. cerevisiae as a model system and its most promising future applications.
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Affiliation(s)
- Crina Popa
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
| | - Marc Valls
- Genetics Department, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB), Bellaterra, Catalonia, Spain
- * E-mail: (GS); (MV)
| | - Guido Sessa
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (GS); (MV)
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20
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Höfling S, Scharnert J, Cromme C, Bertrand J, Pap T, Schmidt MA, Rüter C. Manipulation of pro-inflammatory cytokine production by the bacterial cell-penetrating effector protein YopM is independent of its interaction with host cell kinases RSK1 and PRK2. Virulence 2015; 5:761-71. [PMID: 25513777 DOI: 10.4161/viru.29062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The effector protein Yersinia outer protein M (YopM) of Yersinia enterocolitica has previously been identified and characterized as the first bacterial cell-penetrating protein (CPP). We found that recombinant YopM (rYopM) enters different eukaryotic cell types and downregulates the expression of several pro-inflammatory cytokines (e.g., tumor necrosis factor-α [TNF-α]) after autonomous translocation. After infection with Y. enterocolitica or transfection of host cells, YopM interacts with isoforms of the two kinases ribosomal S6 protein kinase (RSK) and protein kinase C-related kinase (PRK). This interaction caused sustained RSK activation due to interference with dephosphorylation. Here we demonstrate by co-immunoprecipitation that rYopM interacts with RSK and PRK following cell-penetration. We show that autonomously translocated rYopM forms a trimeric complex with different RSK and PRK isoforms. Furthermore, we constructed a series of truncated versions of rYopM to map the domain required for the formation of the complex. The C-terminus of rYopM was identified to be essential for the interaction with RSK1, whereas any deletion in rYopM's leucin-rich repeat domains abrogated PRK2 binding. Moreover, we found that the interaction of cell-penetrating rYopM with RSK led to enhanced autophosphorylation of this kinase at serine 380. Finally, we investigated whether downstream signaling of the trimeric rYopM-RSK/PRK complex modulates the expression of pro-inflammatory TNF-α. Here, we could exclude that interaction with RSK1 and PRK2 is essential for the anti-inflammatory effects of rYopM.
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Affiliation(s)
- Sabrina Höfling
- a Institute of Infectiology; Center for Molecular Biology of Inflammation (ZMBE); University of Münster; Münster, Germany
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21
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Morphological changes in human gastric epithelial cells induced by nuclear targeting of Helicobacter pylori urease subunit A. J Microbiol 2015; 53:406-14. [PMID: 26025173 DOI: 10.1007/s12275-015-5085-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 12/20/2022]
Abstract
Nuclear targeting of bacterial proteins and their pathological effects on host cells are an emerging pathogenic mechanism in bacteria. We have previously reported that urease subunit A (UreA) of Helicobacter pylori targets the nuclei of COS-7 cells through nuclear localization signals (NLSs). This study further investigated whether UreA of H. pylori targets the nuclei of gastric epithelial cells and then induces molecular and cellular changes in the host cells. H. pylori 26695 strain produced and secreted outer membrane vesicles (OMVs). UreA was translocated into gastric epithelial AGS cells through outer membrane vesicles (OMVs) and then targeted the nuclei of AGS cells. Nuclear targeting of rUreA did not induce host cell death, but resulted in morphological changes, such as cellular elongation, in AGS cells. In contrast, AGS cells treated with rUreA?NLS proteins did not show this morphological change. Next generation sequencing revealed that nuclear targeting of UreA differentially regulated 102 morphogenesis- related genes, of which 67 and 35 were up-regulated and down-regulated, respectively. Our results suggest that nuclear targeting of H. pylori UreA induces both molecular and cellular changes in gastric epithelial cells.
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22
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Höfling S, Grabowski B, Norkowski S, Schmidt MA, Rüter C. Current activities of the Yersinia effector protein YopM. Int J Med Microbiol 2015; 305:424-32. [PMID: 25865799 DOI: 10.1016/j.ijmm.2015.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/25/2015] [Accepted: 03/25/2015] [Indexed: 12/13/2022] Open
Abstract
Yersinia outer protein M (YopM) belongs to the group of Yop effector proteins, which are highly conserved among pathogenic Yersinia species. During infection, the effectors are delivered into the host cell cytoplasm via the type 3 secretion system to subvert the host immune response and support the survival of Yersinia. In contrast to the other Yop effectors, YopM does not possess a known enzymatic activity and its molecular mechanism(s) of action remain(s) poorly understood. However, YopM was shown to promote colonization and dissemination of Yersinia, thus being crucial for the pathogen's virulence in vivo. Moreover, YopM interacts with several host cell proteins and might utilize them to execute its anti-inflammatory activities. The results obtained so far indicate that YopM is a multifunctional protein that counteracts the host immune defense by multiple activities, which are at least partially independent of each other. Finally, its functions seem to be also influenced by differences between the specific YopM isoforms expressed by Yersinia subspecies. In this review, we focus on the global as well as more specific contribution of YopM to virulence of Yersinia during infection and point out the various extra- and intracellular molecular functions of YopM. In addition, the novel cell-penetrating ability of recombinant YopM and its potential applications as a self-delivering immunomodulatory therapeutic will be discussed.
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Affiliation(s)
- Sabrina Höfling
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Benjamin Grabowski
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Stefanie Norkowski
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - M Alexander Schmidt
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany.
| | - Christian Rüter
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany.
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23
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Khairalla AS, Omer SA, Mahdavi J, Aslam A, Dufailu OA, Self T, Jonsson AB, Geörg M, Sjölinder H, Royer PJ, Martinez-Pomares L, Ghaemmaghami AM, Wooldridge KG, Oldfield NJ, Ala'Aldeen DAA. Nuclear trafficking, histone cleavage and induction of apoptosis by the meningococcal App and MspA autotransporters. Cell Microbiol 2015; 17:1008-20. [PMID: 25600171 PMCID: PMC5024080 DOI: 10.1111/cmi.12417] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 12/18/2014] [Accepted: 01/13/2015] [Indexed: 01/13/2023]
Abstract
Neisseria meningitidis, a major cause of bacterial meningitis and septicaemia, secretes multiple virulence factors, including the adhesion and penetration protein (App) and meningococcal serine protease A (MspA). Both are conserved, immunogenic, type Va autotransporters harbouring S6‐family serine endopeptidase domains. Previous work suggested that both could mediate adherence to human cells, but their precise contribution to meningococcal pathogenesis was unclear. Here, we confirm that App and MspA are in vivo virulence factors since human CD46‐expressing transgenic mice infected with meningococcal mutants lacking App, MspA or both had improved survival rates compared with mice infected with wild type. Confocal imaging showed that App and MspA were internalized by human cells and trafficked to the nucleus. Cross‐linking and enzyme‐linked immuno assay (ELISA) confirmed that mannose receptor (MR), transferrin receptor 1 (TfR1) and histones interact with MspA and App. Dendritic cell (DC) uptake could be blocked using mannan and transferrin, the specific physiological ligands for MR and TfR1, whereas in vitro clipping assays confirmed the ability of both proteins to proteolytically cleave the core histone H3. Finally, we show that App and MspA induce a dose‐dependent increase in DC death via caspase‐dependent apoptosis. Our data provide novel insights into the roles of App and MspA in meningococcal infection.
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Affiliation(s)
| | - Sherko A Omer
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Jafar Mahdavi
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Akhmed Aslam
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Osman A Dufailu
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Tim Self
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Miriam Geörg
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Hong Sjölinder
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | | | | | | | | | - Neil J Oldfield
- School of Life Sciences, University of Nottingham, Nottingham, UK
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24
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Rüter C, Silva MR, Grabowski B, Lubos ML, Scharnert J, Poceva M, von Tils D, Flieger A, Heesemann J, Bliska JB, Schmidt MA. Rabbit monoclonal antibodies directed at the T3SS effector protein YopM identify human pathogenic Yersinia isolates. Int J Med Microbiol 2014; 304:444-51. [PMID: 24636859 DOI: 10.1016/j.ijmm.2014.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 01/27/2014] [Accepted: 02/02/2014] [Indexed: 01/21/2023] Open
Abstract
The Yersinia outer protein M (YopM) is a type 3 secretion system (T3SS)-dependent effector protein of Yersinia enterocolitica, Yersinia pseudotuberculosis and Yersinia pestis. Although YopM is indispensable for full virulence, its molecular functions still remain largely elusive. Recently, we could identify the recombinant YopM (rYopM) protein derived from the Y. enterocolitica strain 8081 (JB580) as a cell-penetrating protein, which down-regulates the expression of various pro-inflammatory cytokines including TNFα. In this study, we have generated rabbit monoclonal anti-YopM antibodies (RabMabs). RabMabs were characterized by SDS-PAGE and Western blotting using various truncated versions of rYopM to identify epitope-containing domains. RabMabs recognizing either the N- or C-terminus of YopM were characterized further and validated using a collection of 61 pathogenic and non-pathogenic Yersinia strains as well as exemplary strains of major intestinal bacterial pathogens such as Salmonella enterica ssp. enterica, Shigella flexneri and intestinal pathogenic Escherichia coli. RabMab 41.3 directed at the N-terminus of YopM of Y. enterocolitica strain 8081 recognized all YopM-expressing pathogenic Yersinia strains analyzed in this study but failed to recognize non-pathogenic isolates. Thus, RabMab 41.3 might be applicable for the detection of pathogenic Yersinia strains.
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Affiliation(s)
- Christian Rüter
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany.
| | - Mariana Ruiz Silva
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Benjamin Grabowski
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Marie-Luise Lubos
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Julia Scharnert
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Marija Poceva
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Dominik von Tils
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany
| | - Antje Flieger
- Division of Enteropathogenic Bacteria and Salmonella, National Reference Center for Salmonella and other Bacterial Enteric Pathogens, Robert-Koch Institute, Germany
| | - Jürgen Heesemann
- Department of Bacteriology, Max von Pettenkofer Institut, LMU München, Germany
| | - James B Bliska
- Department of Molecular Genetics and Microbiology and Center for Infectious Diseases, Stony Brook University, New York, USA
| | - M Alexander Schmidt
- Institute of Infectiology - Center for Molecular Biology of Inflammation (ZMBE), University of Münster, Germany.
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25
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Scharnert J, Greune L, Zeuschner D, Lubos ML, Alexander Schmidt M, Rüter C. Autonomous translocation and intracellular trafficking of the cell-penetrating and immune-suppressive effector protein YopM. Cell Mol Life Sci 2013; 70:4809-23. [PMID: 23835836 PMCID: PMC11113385 DOI: 10.1007/s00018-013-1413-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/10/2013] [Accepted: 06/21/2013] [Indexed: 11/25/2022]
Abstract
Extracellular Gram-negative pathogenic bacteria target essential cytoplasmic processes of eukaryotic cells by using effector protein delivery systems such as the type III secretion system (T3SS). These secretion systems directly inject effector proteins into the host cell cytoplasm. Among the T3SS-dependent Yop proteins of pathogenic Yersinia, the function of the effector protein YopM remains enigmatic. In a recent study, we demonstrated that recombinant YopM from Yersinia enterocolitica enters host cells autonomously without the presence of bacteria and thus identified YopM as a novel bacterial cell-penetrating protein. Following entry YopM down-regulates expression of pro-inflammatory cytokines such as tumor necrosis factor α. These properties earmark YopM for further development as a novel anti-inflammatory therapeutic. To elucidate the uptake and intracellular targeting mechanisms of this bacterial cell-penetrating protein, we analyzed possible routes of internalization employing ultra-cryo electron microscopy. Our results reveal that under physiological conditions, YopM enters cells predominantly by exploiting endocytic pathways. Interestingly, YopM was detected free in the cytosol and inside the nucleus. We could not observe any colocalization of YopM with secretory membranes, which excludes retrograde transport as the mechanism for cytosolic release. However, our findings indicate that direct membrane penetration and/or an endosomal escape of YopM contribute to the cytosolic and nuclear localization of the protein. Surprisingly, even when endocytosis is blocked, YopM was found to be associated with endosomes. This suggests an intracellular endosome-associated transport of YopM.
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Affiliation(s)
- Julia Scharnert
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Von-Esmarch-Str. 56, 48149 Münster, Germany
| | - Lilo Greune
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Von-Esmarch-Str. 56, 48149 Münster, Germany
| | - Dagmar Zeuschner
- Electron Microscopy Facility, Max-Planck-Institute for Molecular Biomedicine, Röntgenstr. 20, 48149 Münster, Germany
| | - Marie-Luise Lubos
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Von-Esmarch-Str. 56, 48149 Münster, Germany
| | - M. Alexander Schmidt
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Von-Esmarch-Str. 56, 48149 Münster, Germany
| | - Christian Rüter
- Center for Molecular Biology of Inflammation (ZMBE), Institute of Infectiology, Von-Esmarch-Str. 56, 48149 Münster, Germany
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26
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Abstract
Caspase-1-mediated detection of pathogens is a potent arm of the innate immune system. LaRock and Cookson (2012) show that the Yersinia type III secretion effector, YopM, directly inhibits caspase-1.
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Affiliation(s)
- Ine Jørgensen
- Department of Microbiology and Immunology and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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27
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Uittenbogaard AM, Chelvarajan RL, Myers-Morales T, Gorman AA, Brickey WJ, Ye Z, Kaplan AM, Cohen DA, Ting JPY, Straley SC. Toward a molecular pathogenic pathway for Yersinia pestis YopM. Front Cell Infect Microbiol 2012; 2:155. [PMID: 23248776 PMCID: PMC3518861 DOI: 10.3389/fcimb.2012.00155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 11/22/2012] [Indexed: 11/13/2022] Open
Abstract
YopM is one of the six "effector Yops" of the human-pathogenic Yersinia, but its mechanism has not been defined. After delivery to J774A.1 monocyte-like cells, YopM can rapidly bind and activate the serine/threonine kinases RSK1 and PRK2. However, in infected mice, effects of Y. pestis YopM have been seen only after 24-48 h post-infection (p.i.). To identify potential direct effects of YopM in-vivo we tested for effects of YopM at 1 h and 16-18 h p.i. in mice infected systemically with 10(6) bacteria. At 16 h p.i., there was a robust host response to both parent and ΔyopM-1 Y. pestis KIM5. Compared to cells from non-infected mice, CD11b(+) cells from spleens of infected mice produced more than 100-fold greater IFNγ. In the corresponding sera there were more than 100-fold greater amounts of IFNγ, G-CSF, and CXCL9, as well as more than 10-fold greater amounts of IL-6, CXCL10, and CXCL1. The only YopM-related differences were slightly lower CXCL10 and IL-6 in sera from mice infected 16 h with parent compared to ΔyopM-1 Y. pestis. Microarray analysis of the CD11b(+) cells did not identify consistent transcriptional differences of ≥4-fold at 18 h p.i. However, at 1 h p.i. mRNA for early growth response transcription factor 1 (Egr1) was decreased when YopM was present. Bone marrow-derived macrophages infected for 1 h also expressed lower Egr1 message when YopM was present. Infected J774A.1 cells showed greater expression of Egr1 at 1 h p.i. when YopM was present, but this pattern reversed at 3 h. At 6 h p.i., Cxcl10 mRNA was lower in parent-strain infected cells. We conclude that decreased Egr1 expression is a very early transcriptional effect of YopM and speculate that a pathway may exist from RSK1 through Egr1. These studies revealed novel early transcriptional effects of YopM but point to a time after 18 h of infection when critical transitional events lead to later major effects on cytokine gene transcription.
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Affiliation(s)
- Annette M Uittenbogaard
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky Lexington, KY, USA
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Abstract
Epigenetic mechanisms regulate expression of the genome to generate various cell types during development or orchestrate cellular responses to external stimuli. Recent studies highlight that bacteria can affect the chromatin structure and transcriptional program of host cells by influencing diverse epigenetic factors (i.e., histone modifications, DNA methylation, chromatin-associated complexes, noncoding RNAs, and RNA splicing factors). In this article, we first review the molecular bases of the epigenetic language and then describe the current state of research regarding how bacteria can alter epigenetic marks and machineries. Bacterial-induced epigenetic deregulations may affect host cell function either to promote host defense or to allow pathogen persistence. Thus, pathogenic bacteria can be considered as potential epimutagens able to reshape the epigenome. Their effects might generate specific, long-lasting imprints on host cells, leading to a memory of infection that influences immunity and might be at the origin of unexplained diseases.
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Affiliation(s)
- Hélène Bierne
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris F-75015, France.
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Prediction and screening of nuclear targeting proteins with nuclear localization signals in Helicobacter pylori. J Microbiol Methods 2012; 91:490-6. [PMID: 23079023 DOI: 10.1016/j.mimet.2012.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/05/2012] [Accepted: 10/09/2012] [Indexed: 01/26/2023]
Abstract
Host cell pathology induced by nuclear targeting of bacterial proteins has recently been identified as a pathogenic mechanism of bacteria. However, very few bacterial proteins were identified to target the nuclei of host cells. This study was designed to screen nuclear targeting proteins with nuclear localization signals (NLSs) in Helicobacter pylori using a combination of bioinformatic analysis and the Gateway recombinational cloning system. Forty-nine functional or hypothetical proteins were predicted to carry the putative NLSs among 1570 open reading frames (ORFs) of H. pylori 26695. Entire sets of 49 H. pylori ORFs were cloned for the generation of green fluorescent protein-tagged proteins using the Gateway recombinational cloning system. Twenty-six H. pylori proteins with the putative NLSs were found to target in the nuclei of COS-7 cells, whereas 23 were localized in the cytoplasm of host cells. Deletion of NLS sequences from four selected nuclear targeting proteins, urease subunit A, Omp18, secreted protein involved in flagellar motility, and response regulator, resulted in cytoplasmic localization of these mutant proteins. In conclusion, a combination of bioinformatic analysis and the Gateway cloning system was shown to be a useful tool for large-scale screening of nuclear targeting proteins with NLSs in H. pylori, which can be used to better understand the H. pylori-directed host cell pathology.
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Affiliation(s)
- Susan C Straley
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA.
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Moon DC, Choi CH, Lee SM, Lee JH, Kim SI, Kim DS, Lee JC. Nuclear translocation of Acinetobacter baumannii transposase induces DNA methylation of CpG regions in the promoters of E-cadherin gene. PLoS One 2012; 7:e38974. [PMID: 22685614 PMCID: PMC3369853 DOI: 10.1371/journal.pone.0038974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 05/14/2012] [Indexed: 12/18/2022] Open
Abstract
Nuclear targeting of bacterial proteins has emerged as a pathogenic mechanism whereby bacterial proteins induce host cell pathology. In this study, we examined nuclear targeting of Acinetobacter baumannii transposase (Tnp) and subsequent epigenetic changes in host cells. Tnp of A. baumannii ATCC 17978 possesses nuclear localization signals (NLSs), 225RKRKRK230. Transient expression of A. baumannii Tnp fused with green fluorescent protein (GFP) resulted in the nuclear localization of these proteins in COS-7 cells, whereas the truncated Tnp without NLSs fused with GFP were exclusively localized in the cytoplasm. A. baumannii Tnp was found in outer membrane vesicles, which delivered this protein to the nucleus of host cells. Nuclear expression of A. baumannii Tnp fused with GFP in A549 cells induced DNA methylation of CpG regions in the promoters of E-cadherin (CDH1) gene, whereas the cytoplasmic localization of the truncated Tnp without NLSs fused with GFP did not induce DNA methylation. DNA methylation in the promoters of E-cadherin gene induced by nuclear targeting of A. baumannii Tnp resulted in down-regulation of gene expression. In conclusion, our data show that nuclear traffic of A. baumannii Tnp induces DNA methylation of CpG regions in the promoters of E-cadherin gene, which subsequently down-regulates gene expression. This study provides a new insight into the epigenetic control of host genes by bacterial proteins.
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Affiliation(s)
- Dong Chan Moon
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Chul Hee Choi
- Department of Periodontology, University of Florida, Gainesville, Florida, United States of America
| | - Su Man Lee
- Department of Anatomy, Kyungpook National University School of Medicine, Daegu, Korea
| | - Jung Hwa Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Korea
| | - Seung Il Kim
- Division of Life Science, Korea Basic Science Institute, Daejeon, Korea
| | - Dong Sun Kim
- Department of Anatomy, Kyungpook National University School of Medicine, Daegu, Korea
- * E-mail: (JCL); (DSK)
| | - Je Chul Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Korea
- * E-mail: (JCL); (DSK)
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Abstract
The nucleus, at the heart of the eukaryotic cell, hosts and protects the genetic material, governs gene expression and regulates the whole cell physiology, including cell division. A growing number of studies indicate that various animal and plant pathogenic bacteria can deliver factors to this central organelle to subvert host defences by directly interfering with transcription, chromatin-remodelling, RNA splicing or DNA replication and repair. Such bacterial molecules entering the nucleus, which we propose to term 'nucleomodulins', use diverse strategies to hijack nuclear processes by targeting host DNA or an array of nuclear proteins. In some cases, bacteria can even enter the nucleus. These bacterial 'nuclear attacks' might have permanent genetic or long-term epigenetic effects on the host. Studying nucleomodulins and endonuclear bacteria can thus generate new insights into long-term impacts of infectious diseases and create novel tools for biotechnological applications and for deciphering the regulation of nuclear dynamics.
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Affiliation(s)
- Hélène Bierne
- Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris, F-75015, France.
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Moon DC, Gurung M, Lee JH, Lee YS, Choi CW, Kim SI, Lee JC. Screening of nuclear targeting proteins in Acinetobacter baumannii based on nuclear localization signals. Res Microbiol 2012; 163:279-85. [PMID: 22366694 DOI: 10.1016/j.resmic.2012.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 02/01/2012] [Indexed: 12/13/2022]
Abstract
Nuclear targeting of bacterial proteins is an emerging pathogenic mechanism in bacteria. However, due to the absence of an appropriate screening system for nuclear targeting proteins, systematic approaches to nuclear targeting of bacterial proteins and subsequent host cell pathology are limited. In this study, we developed a screening system for nuclear targeting proteins in Acinetobacter baumannii using a combination of bioinformatic analysis based on nuclear localization signal (NLS) and the Gateway(®) recombinational cloning system. Among 3367 open reading frames of A. baumannii ATCC 17978, 34 functional or hypothetical proteins were predicted to carry the putative NLS sequences. Of the 29 clones generated by the Gateway(®) recombinational cloning system, 14 proteins tagged with green fluorescent protein (GFP) were targeted to nuclei of host cells. Among the 14 nuclear targeting proteins, S21, L20, and L32 ribosomal proteins and transposase carried putative nuclear export signal (NES) sequences, but only transposase harbored the functional NES. After translocation to nuclei of host cells, four A. baumannii proteins induced cytotoxicity. In conclusion, we have developed a screening system for nuclear targeting proteins in A. baumannii. This system may open the way to a new field of bacterial pathogenesis.
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Affiliation(s)
- Dong Chan Moon
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu 700 422, Republic of Korea.
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Dean P. Functional domains and motifs of bacterial type III effector proteins and their roles in infection. FEMS Microbiol Rev 2011; 35:1100-25. [PMID: 21517912 DOI: 10.1111/j.1574-6976.2011.00271.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A key feature of the virulence of many bacterial pathogens is the ability to deliver effector proteins into eukaryotic cells via a dedicated type three secretion system (T3SS). Many bacterial pathogens, including species of Chlamydia, Xanthomonas, Pseudomonas, Ralstonia, Shigella, Salmonella, Escherichia and Yersinia, depend on the T3SS to cause disease. T3SS effectors constitute a large and diverse group of virulence proteins that mimic eukaryotic proteins in structure and function. A salient feature of bacterial effectors is their modular architecture, comprising domains or motifs that confer an array of subversive functions within the eukaryotic cell. These domains/motifs therefore represent a fascinating repertoire of molecular determinants with important roles during infection. This review provides a snapshot of our current understanding of bacterial effector domains and motifs where a defined role in infection has been demonstrated.
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Affiliation(s)
- Paul Dean
- Institute of Cell and Molecular Bioscience, Medical School, University of Newcastle, Newcastle Upon Tyne, UK.
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Rüter C, Buss C, Scharnert J, Heusipp G, Schmidt MA. A newly identified bacterial cell-penetrating peptide that reduces the transcription of pro-inflammatory cytokines. J Cell Sci 2010; 123:2190-8. [PMID: 20554895 DOI: 10.1242/jcs.063016] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cell-permeable proteins, also called cell-penetrating peptides (CPPs), have the ability to cross cellular membranes, either alone or in association with bioactive cargo. We identified the Yersinia protein YopM as a novel bacterial cell-permeable protein. Here, we describe the ability of isolated recombinant YopM to enter host cells without a requirement for additional factors. This autonomous translocation of YopM was confirmed in several cell types, indicating that it is an intrinsic property of YopM. Using truncated versions of YopM, we show that either of the two N-terminal alpha-helices of YopM mediates translocation into the cells. Furthermore, the two alpha-helices are also able to deliver heterologous cargo, such as GFP or YopE. In addition, we found that, after entering the cells, YopM is functional and efficiently downregulates the transcription of pro-inflammatory cytokines (such as tumor necrosis factor-alpha and interleukins 12, 15 and 18). This finding suggests the potential use of YopM as a tool for protein delivery. Furthermore, it can lead to important advances in understanding and evaluating the intracellular and molecular function of YopM without the need for infection with Yersinia.
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Affiliation(s)
- Christian Rüter
- Westfälische Wilhelms-Universität Münster, Institut für Infektiologie, Zentrum für Molekularbiologie der Entzündung (ZMBE), Von-Esmarch-Strasse 56, D-48149 Münster, Germany
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Hentschke M, Berneking L, Belmar Campos C, Buck F, Ruckdeschel K, Aepfelbacher M. Yersinia virulence factor YopM induces sustained RSK activation by interfering with dephosphorylation. PLoS One 2010; 5. [PMID: 20957203 PMCID: PMC2950144 DOI: 10.1371/journal.pone.0013165] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 09/14/2010] [Indexed: 12/18/2022] Open
Abstract
Background Pathogenic yersiniae inject several effector proteins (Yops) into host cells, which subverts immune functions and enables the bacteria to survive within the host organism. YopM, whose deletion in enteropathogenic yersiniae results in a dramatic loss of virulence, has previously been shown to form a complex with and activate the multifunctional kinases PKN2 and RSK1 in transfected cells. Methodology/Principal Findings In a near physiological approach with double-affinity-tagged YopM being translocated into the macrophage cell line J774A.1 via the natural type three secretion system of Yersinia we verified the interaction of YopM with PKN2 and RSK1 and detected association with additional PKN and RSK isoforms. In transfected and infected cells YopM induced sustained phosphorylation of RSK at its activation sites serine-380 and serine-221 even in the absence of signalling from its upstream kinase ERK1/2, suggesting inhibition of dephosphorylation. ATP-depletion and in vitro assays using purified components directly confirmed that YopM shields RSK isoforms from phosphatase activity towards serines 380 and 221. Conclusions/Significance Our study suggests that during Yersinia infection YopM induces sustained activation of RSK by blocking dephosphorylation of its activatory phosphorylation sites. This may represent a novel mode of action of a bacterial virulence factor.
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Affiliation(s)
- Moritz Hentschke
- Institute of Medical Microbiology, Virology and Hygiene, University Medical Center Eppendorf, Hamburg, Germany.
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Delineation of regions of the Yersinia YopM protein required for interaction with the RSK1 and PRK2 host kinases and their requirement for interleukin-10 production and virulence. Infect Immun 2010; 78:3529-39. [PMID: 20515922 DOI: 10.1128/iai.00269-10] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The YopM protein of Yersinia sp. is a type III secreted effector that is required for virulence in murine models of infection. YopM has previously been shown to contain leucine-rich repeats (LRRs) and to interact with two host kinases, RSK1 and PRK2, although the consequence of these interactions is unknown. A series of YopM proteins missing different numbers of LRRs or a C-terminal domain were produced and used for in vitro binding reactions to map domains required for interaction with RSK1 and PRK2. A C-terminal domain of YopM (from LRR12 to the C terminus) was shown to be required for interaction with RSK1, while an internal portion encompassing LRR6 to LRR15 was shown to be required for interaction with PRK2. The virulence of a Yersinia pseudotuberculosis Delta yopM mutant in mice via an intravenous route of infection was significantly attenuated. At day 4 postinfection, there were significantly increased levels of gamma interferon and reduced levels of interleukin-18 (IL-18) and IL-10 in the serum of the Delta yopM-infected mice compared to that of mice infected with the wild type, suggesting that YopM action alters the balance of these key cytokines to promote virulence. The PRK2 and RSK1 interaction domains of YopM were both required for IL-10 induction in vivo, irrespective of splenic colonization levels. In an orogastric model of Y. pseudotuberculosis infection, a Delta yopM mutant was defective in dissemination from the intestine to the spleen and significantly reduced in virulence. In addition, Y. pseudotuberculosis mutants expressing YopM proteins unable to interact with either RSK1 (YopM Delta 12-C) or PRK2 (YopM Delta 6-15) were defective for virulence in this assay, indicating that both interaction domains are important for YopM to promote pathogenesis.
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The C-terminal tail of Yersinia pseudotuberculosis YopM is critical for interacting with RSK1 and for virulence. Infect Immun 2010; 78:2584-98. [PMID: 20368345 DOI: 10.1128/iai.00141-10] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Yersinia spp. undermine the immune responses of infected animals by translocating Yops directly into host cells with a type III secretion system. YopM, a leucine-rich repeat protein, is a critical virulence factor in infection. YopM localizes to both the nucleus and the cytoplasm in cultured cells, interacts with mammalian p90 ribosomal S6 kinase 1 (RSK1), and causes a decrease in NK cell populations in spleens. Little is known about the molecular interaction between YopM and RSK1 and its significance in pathogenesis. We performed a systematic deletion analysis of YopM in Yersinia pseudotuberculosis to determine which regions are required for RSK1 interactions, nuclear localization, virulence, and changes in immune cell populations during infection of mice. Full-length YopM associated with RSK1 in at least two protein complexes in infected cells, and deletion of its C-terminal tail abrogated all RSK1 interactions. The C-terminal tail was required for tissue colonization, as yopM mutants that failed to interact with RSK1 were as defective for tissue colonization as was a DeltayopM mutant; however, nuclear localization of YopM was not dependent on its RSK1 interaction. Mutants expressing YopM proteins which do not interact with RSK1 caused more pathology than did the DeltayopM mutant, suggesting that there are other RSK1-independent functions of YopM. Histopathological and flow cytometric analyses of spleens showed that infection with wild-type Y. pseudotuberculosis caused an influx of neutrophils, while mice infected with yopM mutants had increased numbers of macrophages. Decreases in NK cells after Y. pseudotuberculosis infection did not correlate with YopM expression. In conclusion, the C terminus of YopM is essential for RSK1 interactions and for virulence.
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Kloss E, Barrick D. C-terminal deletion of leucine-rich repeats from YopM reveals a heterogeneous distribution of stability in a cooperatively folded protein. Protein Sci 2009; 18:1948-60. [PMID: 19593816 DOI: 10.1002/pro.205] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Terminal deletions of units from alpha-helical repeat proteins have provided insight into the physical origins of their cooperativity. To test if the same principles governing cooperativity apply to beta-sheet-containing repeat proteins, we have created a series of C-terminal deletion constructs from a large leucine-rich repeat (LRR) protein, YopM. We have examined the structure and stability of the resulting deletion constructs by a combination of solution spectroscopy, equilibrium denaturation studies, and limited proteolysis. Surprisingly, a high degree of nonuniformity was found in the stability distribution of YopM. Unlike previously studied repeat proteins, we identified several key LRR that on deletion disrupt nearby structure, at distances as far away as up to three repeats, in YopM. This partial unfolding model is supported by limited proteolysis studies and by point substitution in repeats predicted to be disordered as a result of deletion of adjacent repeats. We show that key internal- and terminal-caps must be present to maintain the structural integrity in adjacent regions (roughly four LRRs long) of decreased stability. The finding that full-length YopM maintains a high level of cooperativity in equilibrium unfolding underscores the importance of interfacial interactions in stabilizing locally unstable regions of structure.
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Affiliation(s)
- Ellen Kloss
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Lee JC, Kim DS, Moon DC, Lee JH, Kim MJ, Lee SM, Lee YS, Kang SW, Lee EJ, Kang SS, Lee E, Hyun SH. Prediction of bacterial proteins carrying a nuclear localization signal and nuclear targeting of HsdM from Klebsiella pneumoniae. J Microbiol 2009; 47:641-5. [PMID: 19851738 DOI: 10.1007/s12275-009-0217-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 08/04/2009] [Indexed: 01/22/2023]
Abstract
Nuclear targeting of bacterial proteins is an emerging pathogenic mechanism whereby bacterial proteins can interact with nuclear molecules and alter the physiology of host cells. The fully sequenced bacterial genome can predict proteins that target the nuclei of host cells based on the presence of nuclear localization signal (NLS). In the present study, we predicted bacterial proteins with the NLS sequences from Klebsiella pneumoniae by bioinformatic analysis, and 13 proteins were identified as carrying putative NLS sequences. Among them, HsdM, a subunit of KpnAl that is a type I restriction-modification system found in K. pneumoniae, was selected for the experimental proof of nuclear targeting in host cells. HsdM carried the NLS sequences, (7)KKAKAKK(13), in the N-terminus. A transient expression of HsdM-EGFP in COS-1 cells exhibited exclusively a nuclear localization of the fusion proteins, whereas the fusion proteins of HsdM with substitutions in residues lysine to alanine in the NLS sequences, (7)AAAKAAA(13), were localized in the cytoplasm. HsdM was co-localized with importin o in the nuclei of host cells. Recombinant HsdM alone methylated the eukaryotic DNA in vitro assay. Although HsdM tested in this study has not been considered to be a virulence factor, the prediction of NLS motifs from the full sequenced genome of bacteria extends our knowledge of functional genomics to understand subcellular targeting of bacterial proteins.
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Affiliation(s)
- Je Chul Lee
- Department of Microbiology, Kyungpook National University School of Medicine, Daegu, Republic of Korea
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Nuclear translocated Ehrlichia chaffeensis ankyrin protein interacts with a specific adenine-rich motif of host promoter and intronic Alu elements. Infect Immun 2009; 77:4243-55. [PMID: 19651857 DOI: 10.1128/iai.00376-09] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ehrlichiae are obligately intracellular bacteria that reside and replicate in phagocytes by circumventing host cell defenses and modulating cellular processes, including host cell gene transcription. However, the mechanisms by which ehrlichiae influence host gene transcription have largely remained undetermined. Numerous ankyrin and tandem repeat-containing proteins associated with host-pathogen interactions have been identified in Ehrlichia species, but their roles in pathobiology are unknown. In this study, we determined by confocal immunofluorescence microscopy and by immunodetection in purified nuclear extracts that the ankyrin repeat-containing protein p200 is translocated to the nuclei of Ehrlichia-infected monocytes. Chromatin immunoprecipitation (ChIP) with DNA sequencing revealed an Ehrlichia chaffeensis p200 interaction located within host promoter and intronic Alu-Sx elements, the most abundant repetitive elements in the human genome. A specific adenine-rich (mid-A-stretch) motif within Alu-Sx elements was identified using electrophoretic mobility shift and NoShift assays. Whole-genome analysis with ChIP and DNA microarray analysis (ChIP-chip) determined that genes (n = 456) with promoter Alu elements primarily related to transcription, apoptosis, ATPase activity, and structural proteins associated with the nucleus and membrane-bound organelles were the primary targets of p200. Several p200 target genes (encoding tumor necrosis factor alpha, Stat1, and CD48) associated with ehrlichial pathobiology were strongly upregulated during infection, as determined by quantitative PCR. This is the first study to identify a nuclear translocation of bacterially encoded protein by E. chaffeensis and to identify a specific binding motif and genes that are primary targets of a novel molecular strategy to reprogram host cell gene expression to promote survival of the pathogen.
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Galán JE. Common themes in the design and function of bacterial effectors. Cell Host Microbe 2009; 5:571-9. [PMID: 19527884 DOI: 10.1016/j.chom.2009.04.008] [Citation(s) in RCA: 237] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 04/10/2009] [Indexed: 11/28/2022]
Abstract
Central to the biology of many pathogenic bacteria are a number of specialized machines, known as type III, type IV, or type VI protein secretion systems. These machines have specifically evolved to deliver bacterial effector proteins into host cells with the capacity to modulate a variety of cellular functions. The identification of the biochemical activities of many effector proteins, coupled with a better understanding of their potential contribution to pathogenesis, has revealed common themes in the evolutionary design and function of these remarkable bacterial proteins.
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Affiliation(s)
- Jorge E Galán
- Section of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536, USA.
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Vlahou G, Schmidt O, Wagner B, Uenlue H, Dersch P, Rivero F, Weissenmayer BA. Yersinia outer protein YopE affects the actin cytoskeleton in Dictyostelium discoideum through targeting of multiple Rho family GTPases. BMC Microbiol 2009; 9:138. [PMID: 19602247 PMCID: PMC2724381 DOI: 10.1186/1471-2180-9-138] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Accepted: 07/14/2009] [Indexed: 01/31/2023] Open
Abstract
Background All human pathogenic Yersinia species share a virulence-associated type III secretion system that translocates Yersinia effector proteins into host cells to counteract infection-induced signaling responses and prevent phagocytosis. Dictyostelium discoideum has been recently used to study the effects of bacterial virulence factors produced by internalized pathogens. In this study we explored the potential of Dictyostelium as model organism for analyzing the effects of ectopically expressed Yersinia outer proteins (Yops). Results The Yersinia pseudotuberculosis virulence factors YopE, YopH, YopM and YopJ were expressed de novo within Dictyostelium and their effects on growth in axenic medium and on bacterial lawns were analyzed. No severe effect was observed for YopH, YopJ and YopM, but expression of YopE, which is a GTPase activating protein for Rho GTPases, was found to be highly detrimental. GFP-tagged YopE expressing cells had less conspicuous cortical actin accumulation and decreased amounts of F-actin. The actin polymerization response upon cAMP stimulation was impaired, although chemotaxis was unaffected. YopE also caused reduced uptake of yeast particles. These alterations are probably due to impaired Rac1 activation. We also found that YopE predominantly associates with intracellular membranes including the Golgi apparatus and inhibits the function of moderately overexpressed RacH. Conclusion The phenotype elicited by YopE in Dictyostelium can be explained, at least in part, by inactivation of one or more Rho family GTPases. It further demonstrates that the social amoeba Dictyostelium discoideum can be used as an efficient and easy-to-handle model organism in order to analyze the function of a translocated GAP protein of a human pathogen.
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Affiliation(s)
- Georgia Vlahou
- Zentrum für Biochemie und Zentrum für Molekulare Medizin, Medizinische Fakultät, Universität Köln, Joseph-Stelzmann-Strasse 52, 50931 Köln, Germany.
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Choi CH, Hyun SH, Kim J, Lee YC, Seol SY, Cho DT, Lee JC. Nuclear translocation and DNAse I-like enzymatic activity ofAcinetobacter baumanniiouter membrane protein A. FEMS Microbiol Lett 2008; 288:62-7. [DOI: 10.1111/j.1574-6968.2008.01323.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Siggers KA, Lesser CF. The Yeast Saccharomyces cerevisiae: a versatile model system for the identification and characterization of bacterial virulence proteins. Cell Host Microbe 2008; 4:8-15. [PMID: 18621006 DOI: 10.1016/j.chom.2008.06.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Microbial pathogens utilize complex secretion systems to deliver proteins into host cells. These effector proteins target and usurp host cell processes to promote infection and cause disease. While secretion systems are conserved, each pathogen delivers its own unique set of effectors. The identification and characterization of these effector proteins has been difficult, often limited by the lack of detectable signal sequences and functional redundancy. Model systems including yeast, worms, flies, and fish are being used to circumvent these issues. This technical review details the versatility and utility of yeast Saccharomyces cerevisiae as a system to identify and characterize bacterial effectors.
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Affiliation(s)
- Keri A Siggers
- Department of Medicine (Microbiology and Molecular Genetics), Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Cambridge, MA 02139, USA
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Shao F. Biochemical functions of Yersinia type III effectors. Curr Opin Microbiol 2008; 11:21-9. [PMID: 18299249 DOI: 10.1016/j.mib.2008.01.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 01/11/2008] [Accepted: 01/18/2008] [Indexed: 01/09/2023]
Abstract
Yersinia uses a type III secretion system (TTSS) to deliver six effector proteins into host cells. These six proteins harbor distinct activities that are mimicries of host functions but often have acquired unique biochemical features. The host targets for these effectors appear to be limited to a few key signaling components such as G proteins and kinases, whereas their models of action are diverse and sophisticated. The functions of these effectors are to subvert the host immune defense response, including alterations of the cytoskeleton structure, inhibition of phagocytic clearance, blockage of cytokine production, and induction of apoptosis. These effectors also interfere with communications between the innate and the adaptive immune response, thus aiding the establishment of a systemic infection.
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Affiliation(s)
- Feng Shao
- National Institute of Biological Sciences, Zhongguancun Life Science Park, Beijing, China.
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Abstract
The pathogenic bacteria Yersinia spp. contain a virulence plasmid that encodes a type III secretion system and effectors. During infection, four of the effectors target the actin cytoskeleton, crippling the phagocytic machinery in the infected cell. The remaining two effectors dampen the innate immune response by targeting important signalling pathways. Although the biochemical activity for each of these effectors is known, the mechanisms involved in their ordered secretion and delivery remain elusive.
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Affiliation(s)
- Jennifer E Trosky
- Department of Microbiology and Immunology, Stanford University School of Medicine, Fairchild Science Building, D300, 299 Campus Drive, Stanford, CA 94305-5124, USA
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Bhavsar AP, Guttman JA, Finlay BB. Manipulation of host-cell pathways by bacterial pathogens. Nature 2007; 449:827-34. [DOI: 10.1038/nature06247] [Citation(s) in RCA: 403] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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The elusive activity of the Yersinia protein kinase A kinase domain is revealed. Trends Microbiol 2007; 15:437-40. [DOI: 10.1016/j.tim.2007.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/09/2007] [Accepted: 09/20/2007] [Indexed: 12/31/2022]
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