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Miner MV, Rauch I. Why put yourself on a pedestal? The pathogenic role of the A/E pedestal. Infect Immun 2024; 92:e0048923. [PMID: 38591884 PMCID: PMC11384751 DOI: 10.1128/iai.00489-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Abstract
Certain Escherichia coli (E. coli) strains are attaching and effacing (A/E) lesion pathogens that primarily infect intestinal epithelial cells. They cause actin restructuring and polymerization within the host cell to create an actin-rich protrusion below the site of adherence, termed the pedestal. Although there is clarity on the pathways initiating pedestal formation, the underlying purpose(s) of the pedestal remains ambiguous. The conservation of pedestal-forming activity across multiple pathogens and redundancy in formation pathways indicate a pathogenic advantage. However, few decisive conclusions have been drawn, given that the results vary between model systems. Some research argues that the pedestal increases the colonization capability of the bacterium. These studies utilize A/E pathogens specifically deficient in pedestal formation to evaluate adhesion and intestinal colonization following infection. There have been many proposed mechanisms for the colonization benefit conferred by the pedestal. One suggested benefit is that the pedestal allows for direct cytosolic anchoring through incorporation of the established host cortical actin, causing a stable link between the pathogen and cell structure. The pedestal may confer enhanced motility, as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC) are better able to migrate on the surface of host cells and infect neighboring cells in the presence of the pedestal. Additionally, some research suggests that the pedestal improves effector delivery. This review will investigate the purpose of pedestal formation using evidence from recent literature and will critically evaluate the methodology and model systems. Most importantly, we will contextualize the proposed functions to reconcile potential synergistic effects.
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Affiliation(s)
- M. V. Miner
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
| | - I. Rauch
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon, USA
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2
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Vieira MFM, Hernandez G, Zhong Q, Arbesú M, Veloso T, Gomes T, Martins ML, Monteiro H, Frazão C, Frankel G, Zanzoni A, Cordeiro TN. The pathogen-encoded signalling receptor Tir exploits host-like intrinsic disorder for infection. Commun Biol 2024; 7:179. [PMID: 38351154 PMCID: PMC10864410 DOI: 10.1038/s42003-024-05856-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/26/2024] [Indexed: 02/16/2024] Open
Abstract
The translocated intimin receptor (Tir) is an essential type III secretion system (T3SS) effector of attaching and effacing pathogens contributing to the global foodborne disease burden. Tir acts as a cell-surface receptor in host cells, rewiring intracellular processes by targeting multiple host proteins. We investigated the molecular basis for Tir's binding diversity in signalling, finding that Tir is a disordered protein with host-like binding motifs. Unexpectedly, also are several other T3SS effectors. By an integrative approach, we reveal that Tir dimerises via an antiparallel OB-fold within a highly disordered N-terminal cytosolic domain. Also, it has a long disordered C-terminal cytosolic domain partially structured at host-like motifs that bind lipids. Membrane affinity depends on lipid composition and phosphorylation, highlighting a previously unrecognised host interaction impacting Tir-induced actin polymerisation and cell death. Furthermore, multi-site tyrosine phosphorylation enables Tir to engage host SH2 domains in a multivalent fuzzy complex, consistent with Tir's scaffolding role and binding promiscuity. Our findings provide insights into the intracellular Tir domains, highlighting the ability of T3SS effectors to exploit host-like protein disorder as a strategy for host evasion.
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Affiliation(s)
- Marta F M Vieira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Guillem Hernandez
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Qiyun Zhong
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, UK
| | - Miguel Arbesú
- Department of NMR-supported Structural Biology, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
- InstaDeep Ltd, 5 Merchant Square, London, UK
| | - Tiago Veloso
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Tiago Gomes
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Maria L Martins
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Hugo Monteiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Carlos Frazão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal
| | - Gad Frankel
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, UK
| | - Andreas Zanzoni
- Aix-Marseille Université, Inserm, TAGC, UMR_S1090, Marseille, France
| | - Tiago N Cordeiro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, Oeiras, Portugal.
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3
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Sámano-Sánchez H, Gibson TJ, Chemes LB. Using Linear Motif Database Resources to Identify SH2 Domain Binders. Methods Mol Biol 2023; 2705:153-197. [PMID: 37668974 DOI: 10.1007/978-1-0716-3393-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
The SH2-binding phosphotyrosine class of short linear motifs (SLiMs) are key conditional regulatory elements, particularly in signaling protein complexes beneath the cell's plasma membrane. In addition to transmitting cellular signaling information, they can also play roles in cellular hijack by invasive pathogens. Researchers can take advantage of bioinformatics tools and resources to predict the motifs at conserved phosphotyrosine residues in regions of intrinsically disordered protein. A candidate SH2-binding motif can be established and assigned to one or more of the SH2 domain subgroups. It is, however, not so straightforward to predict which SH2 domains are capable of binding the given candidate. This is largely due to the cooperative nature of the binding amino acids which enables poorer binding residues to be tolerated when the other residues are optimal. High-throughput peptide arrays are powerful tools used to derive SH2 domain-binding specificity, but they are unable to capture these cooperative effects and also suffer from other shortcomings. Tissue and cell type expression can help to restrict the list of available interactors: for example, some well-studied SH2 domain proteins are only present in the immune cell lineages. In this article, we provide a table of motif patterns and four bioinformatics strategies that introduce a range of tools that can be used in motif hunting in cellular and pathogen proteins. Experimental followup is essential to determine which SH2 domain/motif-containing proteins are the actual functional partners.
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Affiliation(s)
- Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Zhejiang University School of Medicine, International Campus, Zhejiang University, Haining, China
- Biomedical Sciences, Edinburgh Medical School, The University of Edinburgh, Edinburgh, UK
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Lucía B Chemes
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Argentina.
- Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, San Martín, Argentina.
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4
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Bending over backwards: BAR proteins and the actin cytoskeleton in mammalian receptor-mediated endocytosis. Eur J Cell Biol 2022; 101:151257. [PMID: 35863103 DOI: 10.1016/j.ejcb.2022.151257] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 11/21/2022] Open
Abstract
The role of the actin cytoskeleton during receptor-mediated endocytosis (RME) has been well characterized in yeast for many years. Only more recently has the interplay between the actin cytoskeleton and RME been extensively explored in mammalian cells. These studies have revealed the central roles of BAR proteins in RME, and have demonstrated significant roles of BAR proteins in linking the actin cytoskeleton to this cellular process. The actin cytoskeleton generates and transmits mechanical force to promote the extension of receptor-bound endocytic vesicles into the cell. Many adaptor proteins link and regulate the actin cytoskeleton at the sites of endocytosis. This review will cover key effectors, adaptors and signalling molecules that help to facilitate the invagination of the cell membrane during receptor-mediated endocytosis, including recent insights gained on the roles of BAR proteins. The final part of this review will explore associations of alterations to genes encoding BAR proteins with cancer.
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5
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Mészáros B, Sámano-Sánchez H, Alvarado-Valverde J, Čalyševa J, Martínez-Pérez E, Alves R, Shields DC, Kumar M, Rippmann F, Chemes LB, Gibson TJ. Short linear motif candidates in the cell entry system used by SARS-CoV-2 and their potential therapeutic implications. Sci Signal 2021; 14:eabd0334. [PMID: 33436497 PMCID: PMC7928535 DOI: 10.1126/scisignal.abd0334] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 12/10/2020] [Indexed: 12/12/2022]
Abstract
The first reported receptor for SARS-CoV-2 on host cells was the angiotensin-converting enzyme 2 (ACE2). However, the viral spike protein also has an RGD motif, suggesting that cell surface integrins may be co-receptors. We examined the sequences of ACE2 and integrins with the Eukaryotic Linear Motif (ELM) resource and identified candidate short linear motifs (SLiMs) in their short, unstructured, cytosolic tails with potential roles in endocytosis, membrane dynamics, autophagy, cytoskeleton, and cell signaling. These SLiM candidates are highly conserved in vertebrates and may interact with the μ2 subunit of the endocytosis-associated AP2 adaptor complex, as well as with various protein domains (namely, I-BAR, LC3, PDZ, PTB, and SH2) found in human signaling and regulatory proteins. Several motifs overlap in the tail sequences, suggesting that they may act as molecular switches, such as in response to tyrosine phosphorylation status. Candidate LC3-interacting region (LIR) motifs are present in the tails of integrin β3 and ACE2, suggesting that these proteins could directly recruit autophagy components. Our findings identify several molecular links and testable hypotheses that could uncover mechanisms of SARS-CoV-2 attachment, entry, and replication against which it may be possible to develop host-directed therapies that dampen viral infection and disease progression. Several of these SLiMs have now been validated to mediate the predicted peptide interactions.
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Affiliation(s)
- Bálint Mészáros
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.
| | - Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Jesús Alvarado-Valverde
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Jelena Čalyševa
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Elizabeth Martínez-Pérez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
- Laboratorio de bioinformática estructural, Fundación Instituto Leloir, C1405BWE Buenos Aires, Argentina
| | - Renato Alves
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Denis C Shields
- School of Medicine, University College Dublin, Dublin 4, Ireland
| | - Manjeet Kumar
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.
| | - Friedrich Rippmann
- Computational Chemistry & Biology, Merck KGaA, Frankfurter Str. 250, 64293 Darmstadt, Germany
| | - Lucía B Chemes
- Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde", IIB-UNSAM, IIBIO-CONICET, Universidad Nacional de San Martín, CP1650 San Martín, Buenos Aires, Argentina.
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.
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6
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Jarin Z, Pak AJ, Bassereau P, Voth GA. Lipid-Composition-Mediated Forces Can Stabilize Tubular Assemblies of I-BAR Proteins. Biophys J 2020; 120:46-54. [PMID: 33248130 DOI: 10.1016/j.bpj.2020.11.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/20/2020] [Accepted: 11/13/2020] [Indexed: 12/17/2022] Open
Abstract
Collective action by inverse-Bin/Amphiphysin/Rvs (I-BAR) domains drive micron-scale membrane remodeling. The macroscopic curvature sensing and generation behavior of I-BAR domains is well characterized, and computational models have suggested various mechanisms on simplified membrane systems, but there remain missing connections between the complex environment of the cell and the models proposed thus far. Here, we show a connection between the role of protein curvature and lipid clustering in the relaxation of large membrane deformations. When we include phosphatidylinositol 4,5-bisphosphate-like lipids that preferentially interact with the charged ends of an I-BAR domain, we find clustering of phosphatidylinositol 4,5-bisphosphate-like lipids that induce a directional membrane-mediated interaction between membrane-bound I-BAR domains. Lipid clusters mediate I-BAR domain interactions and cause I-BAR domain aggregates that would not arise through membrane fluctuation-based or curvature-based interactions. Inside of membrane protrusions, lipid cluster-mediated interaction draws long side-by-side aggregates together, resulting in more cylindrical protrusions as opposed to bulbous, irregularly shaped protrusions.
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Affiliation(s)
- Zack Jarin
- Pritzker School for Molecular Engineering, The University of Chicago, Chicago, Illinois
| | - Alexander J Pak
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago, Chicago, Illinois
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France; UPMC University Paris 6, Sorbonne Universites, Paris, France
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago, Chicago, Illinois.
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7
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Duncan-Lowey JK, Wiscovitch AL, Wood TE, Goldberg MB, Russo BC. Shigella flexneri Disruption of Cellular Tension Promotes Intercellular Spread. Cell Rep 2020; 33:108409. [PMID: 33238111 PMCID: PMC7792532 DOI: 10.1016/j.celrep.2020.108409] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 09/25/2020] [Accepted: 10/29/2020] [Indexed: 01/18/2023] Open
Abstract
During infection, some bacterial pathogens invade the eukaryotic cytosol and spread between cells of an epithelial monolayer. Intercellular spread occurs when these pathogens push against the plasma membrane, forming protrusions that are engulfed by adjacent cells. Here, we show that IpaC, a Shigella flexneri type 3 secretion system protein, binds the host cell-adhesion protein β-catenin and facilitates efficient protrusion formation. S. flexneri producing a point mutant of IpaC that cannot interact with β-catenin is defective in protrusion formation and spread. Spread is restored by chemical reduction of intercellular tension or genetic depletion of β-catenin, and the magnitude of the protrusion defect correlates with membrane tension, indicating that IpaC reduces membrane tension, which facilitates protrusion formation. IpaC stabilizes adherens junctions and does not alter β-catenin localization at the membrane. Thus, Shigella, like other bacterial pathogens, reduces intercellular tension to efficiently spread between cells.
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Affiliation(s)
- Jeffrey K. Duncan-Lowey
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Present address: Department of Immunobiology, Yale School of Medicine, New Haven, CT 06511, USA
| | - Alexandra L. Wiscovitch
- Research Scholar Initiative, The Graduate School of Arts and Sciences, Harvard University, Cambridge, MA 02138, USA,Present address: Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL 32611, USA
| | - Thomas E. Wood
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Marcia B. Goldberg
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA,Correspondence: (M.B.G.), (B.C.R.)
| | - Brian C. Russo
- Center for Bacterial Pathogenesis, Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA,Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA,Present address: Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, USA,Lead Contact,Correspondence: (M.B.G.), (B.C.R.)
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8
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Kumar M, Gouw M, Michael S, Sámano-Sánchez H, Pancsa R, Glavina J, Diakogianni A, Valverde JA, Bukirova D, Čalyševa J, Palopoli N, Davey NE, Chemes LB, Gibson TJ. ELM-the eukaryotic linear motif resource in 2020. Nucleic Acids Res 2020; 48:D296-D306. [PMID: 31680160 PMCID: PMC7145657 DOI: 10.1093/nar/gkz1030] [Citation(s) in RCA: 129] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/18/2019] [Accepted: 10/23/2019] [Indexed: 12/20/2022] Open
Abstract
The eukaryotic linear motif (ELM) resource is a repository of manually curated experimentally validated short linear motifs (SLiMs). Since the initial release almost 20 years ago, ELM has become an indispensable resource for the molecular biology community for investigating functional regions in many proteins. In this update, we have added 21 novel motif classes, made major revisions to 12 motif classes and added >400 new instances mostly focused on DNA damage, the cytoskeleton, SH2-binding phosphotyrosine motifs and motif mimicry by pathogenic bacterial effector proteins. The current release of the ELM database contains 289 motif classes and 3523 individual protein motif instances manually curated from 3467 scientific publications. ELM is available at: http://elm.eu.org.
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Affiliation(s)
- Manjeet Kumar
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Marc Gouw
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Sushama Michael
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Rita Pancsa
- Institute of Enzymology, Research Centre for Natural Sciences, Budapest 1117, Hungary
| | - Juliana Glavina
- Instituto de Investigaciones Biotecnológicas (IIBio) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín. Av. 25 de Mayo y Francia, CP1650, Buenos Aires, Argentina
| | - Athina Diakogianni
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Jesús Alvarado Valverde
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
| | - Dayana Bukirova
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Nazarbayev University, Nur-Sultan 010000, Kazakhstan
| | - Jelena Čalyševa
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany.,Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences
| | - Nicolas Palopoli
- Department of Science and Technology, Universidad Nacional de Quilmes - CONICET, Bernal B1876BXD, Buenos Aires, Argentina
| | - Norman E Davey
- The Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Rd, Chelsea, London SW3 6JB, UK
| | - Lucía B Chemes
- Instituto de Investigaciones Biotecnológicas (IIBio) and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de San Martín. Av. 25 de Mayo y Francia, CP1650, Buenos Aires, Argentina
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg 69117, Germany
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9
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EspFu-Mediated Actin Assembly Enhances Enteropathogenic Escherichia coli Adherence and Activates Host Cell Inflammatory Signaling Pathways. mBio 2020; 11:mBio.00617-20. [PMID: 32291304 PMCID: PMC7157822 DOI: 10.1128/mbio.00617-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
EPEC is among the leading causes of diarrheal disease worldwide. The colonization of the gut mucosa by EPEC results in actin pedestal formation at the site of bacterial attachment. These pedestals are referred to as attaching and effacing (AE) lesions. Here, we exploit the different molecular mechanisms used by EPEC to induce AE lesions on epithelial cells, showing that the effector EspFu is associated with increased bacterial attachment and enhanced epithelial colonization compared to the Tir-Nck pathway. Moreover, we also showed that actin pedestal formation can counterbalance the anti-inflammatory activity induced by EPEC, especially when driven by EspFu. Collectively, our findings provide new insights into virulence mechanisms employed by EPEC to colonize epithelial cells, as well as the host response to this enteric pathogen. The translocation of effectors into the host cell through type 3 secretion systems (T3SS) is a sophisticated strategy employed by pathogenic bacteria to subvert host responses and facilitate colonization. Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) utilize the Tir and EspFu (also known as TccP) effectors to remodel the host cytoskeleton, culminating in the formation of attaching and effacing (AE) lesions on enterocytes. While some EPEC strains require tyrosine phosphorylation of Tir and recruitment of the host Nck to trigger actin polymerization, EHEC and certain EPEC strains, whose Tir is not phosphorylated, rely on the effector EspFu for efficient actin remodeling. Here, we investigated the role played by Tir-Nck and Tir-EspFu actin polymerization pathways during the infection of epithelial cells, as well as the host transcriptional response to the AE lesion formation induced by EPEC. We found that EspFu-mediated actin assembly promotes bacterial attachment and epithelial colonization more efficiently than Tir-Nck. Moreover, we showed that both actin polymerization mechanisms can activate inflammatory pathways and reverse the anti-inflammatory response induced by EPEC in epithelial cells. However, this activity is remarkably more evident in infections with EspFu-expressing EPEC strains. This study demonstrates the complex interactions between effector-mediated actin remodeling and inflammation. Different strains carry different combinations of these two effectors, highlighting the plasticity of pathogenic E. coli enteric infections.
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10
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Sámano-Sánchez H, Gibson TJ. Mimicry of Short Linear Motifs by Bacterial Pathogens: A Drugging Opportunity. Trends Biochem Sci 2020; 45:526-544. [PMID: 32413327 DOI: 10.1016/j.tibs.2020.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/11/2022]
Abstract
Bacterial pathogens have developed complex strategies to successfully survive and proliferate within their hosts. Throughout the infection cycle, direct interaction with host cells occurs. Many bacteria have been found to secrete proteins, such as effectors and toxins, directly into the host cell with the potential to interfere with cell regulatory processes, either enzymatically or through protein-protein interactions (PPIs). Short linear motifs (SLiMs) are abundant peptide modules in cell signaling proteins. Here, we cover the reported examples of eukaryotic-like SLiM mimicry being used by pathogenic bacteria to hijack host cell machinery and discuss how drugs targeting SLiM-regulated cell signaling networks are being evaluated for interference with bacterial infections. This emerging anti-infective opportunity may become an essential contributor to antibiotic replacement strategies.
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Affiliation(s)
- Hugo Sámano-Sánchez
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, 69120 Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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11
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Jarin Z, Tsai FC, Davtyan A, Pak AJ, Bassereau P, Voth GA. Unusual Organization of I-BAR Proteins on Tubular and Vesicular Membranes. Biophys J 2019; 117:553-562. [PMID: 31349990 PMCID: PMC6697384 DOI: 10.1016/j.bpj.2019.06.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 06/19/2019] [Accepted: 06/21/2019] [Indexed: 12/26/2022] Open
Abstract
Protein-mediated membrane remodeling is a ubiquitous and critical process for proper cellular function. Inverse Bin/Amphiphysin/Rvs (I-BAR) domains drive local membrane deformation as a precursor to large-scale membrane remodeling. We employ a multiscale approach to provide the molecular mechanism of unusual I-BAR domain-driven membrane remodeling at a low protein surface concentration with near-atomistic detail. We generate a bottom-up coarse-grained model that demonstrates similar membrane-bound I-BAR domain aggregation behavior as our recent Mesoscopic Membrane with Explicit Proteins model. Together, these models bridge several length scales and reveal an aggregation behavior of I-BAR domains. We find that at low surface coverage (i.e., low bound protein density), I-BAR domains form transient, tip-to-tip strings on periodic flat membrane sheets. Inside of lipid bilayer tubules, we find linear aggregates parallel to the axis of the tubule. Finally, we find that I-BAR domains form tip-to-tip aggregates around the edges of membrane domes. These results are supported by in vitro experiments showing low curvature bulges surrounded by I-BAR domains on giant unilamellar vesicles. Overall, our models reveal new I-BAR domain aggregation behavior in membrane tubules and on the surface of vesicles at low surface concentration that add insight into how I-BAR domain proteins may contribute to certain aspects of membrane remodeling in cells.
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Affiliation(s)
- Zack Jarin
- Pritzker School for Molecular Engineering, The University of Chicago, Chicago, Illinois
| | - Feng-Ching Tsai
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France; Sorbonne Universités, UPMC University Paris 06, Paris, France
| | - Aram Davtyan
- Department of Chemistry, Chicago Center for Theoretical Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois
| | - Alexander J Pak
- Department of Chemistry, Chicago Center for Theoretical Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois
| | - Patricia Bassereau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France; Sorbonne Universités, UPMC University Paris 06, Paris, France
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, The James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois.
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12
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Zhou R, Chen Z, Hao D, Wang Y, Zhang Y, Yi X, Lyu LD, Liu H, Zou Q, Chu Y, Ge B, Yan D. Enterohemorrhagic Escherichia coli Tir inhibits TAK1 activation and mediates immune evasion. Emerg Microbes Infect 2019; 8:734-748. [PMID: 31130074 PMCID: PMC6542180 DOI: 10.1080/22221751.2019.1620589] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Many pathogens infect hosts through various immune evasion strategies. However, the molecular mechanisms by which pathogen proteins modulate and evade the host immune response remain unclear. Enterohemorrhagic Escherichia coli (EHEC) is a pathological strain that can induce mitogen-activated protein (MAP) kinase (Erk, Jnk and p38 MAPK) and NF-κB pathway activation and proinflammatory cytokine production, which then causes diarrheal diseases such as hemorrhagic colitis and hemolytic uremic syndrome. Transforming growth factor β-activated kinase-1 (TAK1) is a key regulator involved in distinct innate immune signalling pathways. Here we report that EHEC translocated intimin receptor (Tir) protein inhibits the expression of EHEC-induced proinflammatory cytokines by interacting with the host tyrosine phosphatase SHP-1, which is dependent on the phosphorylation of immunoreceptor tyrosine-based inhibition motifs (ITIMs). Mechanistically, the association of EHEC Tir with SHP-1 facilitated the recruitment of SHP-1 to TAK1 and inhibited TAK1 phosphorylation, which then negatively regulated K63-linked polyubiquitination of TAK1 and downstream signal transduction. Taken together, these results suggest that EHEC Tir negatively regulates proinflammatory responses by inhibiting the activation of TAK1, which is essential for immune evasion and could be a potential target for the treatment of bacterial infection.
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Affiliation(s)
- Ruixue Zhou
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Zijuan Chen
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Doudou Hao
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Yu Wang
- b Department of Microbiology and Biochemical Pharmacy, National Engineering Research Centre of Immunological Products, College of Pharmacy , Army Medical University , Chongqing , People's Republic of China
| | - Yihua Zhang
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Xianfu Yi
- c School of Biomedical Engineering , Tianjin Medical University , Tianjin , People's Republic of China
| | - Liang-Dong Lyu
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Haipeng Liu
- d Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital , Tongji University School of Medicine , Shanghai , People's Republic of China
| | - Quanming Zou
- b Department of Microbiology and Biochemical Pharmacy, National Engineering Research Centre of Immunological Products, College of Pharmacy , Army Medical University , Chongqing , People's Republic of China
| | - Yiwei Chu
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
| | - Baoxue Ge
- d Shanghai Key Laboratory of Tuberculosis, Shanghai Pulmonary Hospital , Tongji University School of Medicine , Shanghai , People's Republic of China.,e Department of Microbiology and Immunology , Tongji University School of Medicine , Shanghai , People's Republic of China
| | - Dapeng Yan
- a Department of Immunology, School of Basic Medical Sciences & Shanghai Public Health Clinical Center, Key Laboratory of Medical Molecular Virology of MOE/MOH , Fudan University , Shanghai , People's Republic of China
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13
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Postema MM, Grega-Larson NE, Neininger AC, Tyska MJ. IRTKS (BAIAP2L1) Elongates Epithelial Microvilli Using EPS8-Dependent and Independent Mechanisms. Curr Biol 2018; 28:2876-2888.e4. [PMID: 30197089 DOI: 10.1016/j.cub.2018.07.022] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 06/05/2018] [Accepted: 07/09/2018] [Indexed: 11/24/2022]
Abstract
Transporting epithelial cells like those that line the gut build large arrays of actin-supported protrusions called microvilli, which extend from the apical surface into luminal spaces to increase functional surface area. Although critical for maintaining physiological homeostasis, mechanisms controlling the formation of microvilli remain poorly understood. Here, we report that the inverse-bin-amphiphysin-Rvs (I-BAR)-domain-containing protein insulin receptor tyrosine kinase substrate (IRTKS) (also known as BAIAP2L1) promotes the growth of epithelial microvilli. Super-resolution microscopy and live imaging of differentiating epithelial cells revealed that IRTKS localizes to the distal tips of actively growing microvilli via a mechanism that requires its N-terminal I-BAR domain. At microvillar tips, IRTKS promotes elongation through a mechanism involving its C-terminal actin-binding WH2 domain. IRTKS can also drive microvillar elongation using its SH3 domain to recruit the bundling protein EPS8 to microvillar tips. These results provide new insight on mechanisms that control microvillar growth during the differentiation of transporting epithelial cells and help explain why IRTKS is targeted by enteric pathogens that disrupt microvillar structure during infection of the intestinal epithelium.
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Affiliation(s)
- Meagan M Postema
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Nathan E Grega-Larson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Abigail C Neininger
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA.
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14
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Mao C, Gu J, Wang HG, Fang Y, Yang P, Tang B, Li N, Wang TT, Zou QM, Li Q. Translocation of enterohemorrhagic Escherichia coli effector Tir to the plasma membrane via host Golgi apparatus. Mol Med Rep 2017. [PMID: 28627613 DOI: 10.3892/mmr.2017.6763] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The translocated intimin receptor (Tir) is a canonical type III secretion system effector, secreted by the enterohemorrhagic Escherichia coli (E. coli). This receptor alters the regular cellular processing of host cells, to promote intracellular bacterial replication and evasion of the host immune system. Tir is translocated and integrated into the host cell plasma membrane, a process required for its pathogenic activity in these cells, however, the underlying mechanisms of how this occurs remain to be elucidated. The present study used immunofluorescence and immunoelectron microscopy to demonstrate that the Tir of enterohemorrhagic E. coli was localized to the plasma membrane and colocalized with the 58K Golgi protein of the host cells. Treatment with brefeldin A destroyed the Golgi structure, inhibited the formation of actin pedestal and blocked the localization of Tir on the host cell plasma membrane. The results of the present study suggested that Tir is translocated to the host plasma membrane in a Golgi‑dependent manner. It may mimic the activities of eukaryotic secretory proteins in order to make use of the Golgi apparatus for transportation and integration into the plasma membrane. These findings reveal a novel trafficking pathway for the translocation of bacterial secretory effectors to their specific subcellular compartments.
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Affiliation(s)
- Chan Mao
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
| | - Jiang Gu
- National Engineering Research Center for Immunobiological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing 400038, P.R. China
| | - Hai-Guang Wang
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
| | - Yao Fang
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
| | - Ping Yang
- Department of Core Facilities of Imaging Facility, Medical College of Zhejiang University, Hangzhou, Zhejiang 310031, P.R. China
| | - Bin Tang
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
| | - Na Li
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
| | - Ting-Ting Wang
- National Engineering Research Center for Immunobiological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing 400038, P.R. China
| | - Quan-Ming Zou
- National Engineering Research Center for Immunobiological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Third Military Medical University, Chongqing 400038, P.R. China
| | - Qian Li
- Department of Clinical Microbiology and Immunology, Southwest Hospital and College of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, P.R. China
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15
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Kühn S, Mannherz HG. Actin: Structure, Function, Dynamics, and Interactions with Bacterial Toxins. Curr Top Microbiol Immunol 2016; 399:1-34. [PMID: 27848038 DOI: 10.1007/82_2016_45] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Actin is one of the most abundant proteins in any eukaryotic cell and an indispensable component of the cytoskeleton. In mammalian organisms, six highly conserved actin isoforms can be distinguished, which differ by only a few amino acids. In non-muscle cells, actin polymerizes into actin filaments that form actin structures essential for cell shape stabilization, and participates in a number of motile activities like intracellular vesicle transport, cytokinesis, and also cell locomotion. Here, we describe the structure of monomeric and polymeric actin, the polymerization kinetics, and its regulation by actin-binding proteins. Probably due to its conserved nature and abundance, actin and its regulating factors have emerged as prefered targets of bacterial toxins and effectors, which subvert the host actin cytoskeleton to serve bacterial needs.
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Affiliation(s)
- Sonja Kühn
- Department of Cell Biology and Infection, Institut Pasteur, Paris, France
| | - Hans Georg Mannherz
- Department of Anatomy and Molecular Embryology, Ruhr-University, Bochum, Germany.
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16
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Chao A, Tsai CL, Jung SM, Chuang WC, Kao C, Hsu A, Chen SH, Lin CY, Lee YC, Lee YS, Wang TH, Wang HS, Lai CH. BAI1-Associated Protein 2-Like 1 (BAIAP2L1) Is a Potential Biomarker in Ovarian Cancer. PLoS One 2015. [PMID: 26222696 PMCID: PMC4519316 DOI: 10.1371/journal.pone.0133081] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Brain-specific angiogenesis inhibitor 1 (BAI1)-associated protein 2-like 1 (BAIAP2L1), also known as insulin receptor tyrosine kinase substrate (IRTKS), is involved in plasma membrane protrusion and actin formation during cell morphogenesis and migration. BAIAP2L1 is recently reported to promote cell proliferation through activation of the EGFR-ERK pathway in hepatocellular carcinoma. In this study, we report the first comprehensive study of BAIAP2L1 upregulation in human ovarian cancer. Upregulation of BAIAP2L1 in ovarian tumors was first found during RNA screening and confirmed by immunohistochemical studies on ovarian cancers and other cancer types. Significant upregulation of BAIAP2L1 in ovarian cancer was validated by analyzing multiple independent cohorts in publicly available data sets. Furthermore, BAIAP2L1 protein expression in metastatic lesions was higher than the corresponding primary tumors. Functional assays in ovarian cancer cells revealed that BAIAP2L1 is involved in promoting cell proliferation and avoiding apoptosis. In conclusion, results of this study not only indicate that BAIAP2L1 can be used as a biomarker for human ovarian cancer but also reveal its role in cancer biology. Further elucidation of the role of BAIAP2L1 in context of the insulin receptor signaling pathways of cancer cells is warranted for developing cancer therapeutics by targeting cancer-specific metabolism.
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Affiliation(s)
- Angel Chao
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Chia-Lung Tsai
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Shih-Ming Jung
- Department of Clinical Pathology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chi Chuang
- Graduate Institute of Biomedical Science, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chieh Kao
- Graduate Institute of Biomedical Science, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - An Hsu
- Graduate Institute of Biomedical Science, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shun-Hua Chen
- Graduate Institute of Biomedical Science, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chiao-Yun Lin
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Yi-Chao Lee
- College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Yun-Shien Lee
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Department of Biotechnology, Ming-Chuan University, Taoyuan, Taiwan
- * E-mail: (THW); (YSL)
| | - Tzu-Hao Wang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
- Genomic Medicine Research Core Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- * E-mail: (THW); (YSL)
| | - Hsin-Shih Wang
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Chyong-Huey Lai
- Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
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17
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Abstract
Adhesins are a group of proteins in enterohemorrhagic Escherichia coli (EHEC) that are involved in the attachment or colonization of this pathogen to abiotic (plastic or steel) and biological surfaces, such as those found in bovine and human intestines. This review provides the most up-to-date information on these essential adhesion factors, summarizing important historical discoveries and analyzing the current and future state of this research. In doing so, the proteins intimin and Tir are discussed in depth, especially regarding their role in the development of attaching and effacing lesions and in EHEC virulence. Further, a series of fimbrial proteins (Lpf1, Lpf2, curli, ECP, F9, ELF, Sfp, HCP, and type 1 fimbriae) are also described, emphasizing their various contributions to adherence and colonization of different surfaces and their potential use as genetic markers in detection and classification of different EHEC serotypes. This review also discusses the role of several autotransporter proteins (EhaA-D, EspP, Saa and Sab, and Cah), as well as other proteins associated with adherence, such as flagella, EibG, Iha, and OmpA. While these proteins have all been studied to varying degrees, all of the adhesins summarized in this chapter have been linked to different stages of the EHEC life cycle, making them good targets for the development of more effective diagnostics and therapeutics.
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Affiliation(s)
- Brian D. McWilliams
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
| | - Alfredo G. Torres
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, 77555. USA
- Department of Pathology and Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, 77555. USA
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18
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Kast DJ, Yang C, Disanza A, Boczkowska M, Madasu Y, Scita G, Svitkina T, Dominguez R. Mechanism of IRSp53 inhibition and combinatorial activation by Cdc42 and downstream effectors. Nat Struct Mol Biol 2014; 21:413-22. [PMID: 24584464 DOI: 10.1038/nsmb.2781] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/28/2014] [Indexed: 12/16/2022]
Abstract
The Rho family GTPase effector IRSp53 has essential roles in filopodia formation and neuronal development, but its regulatory mechanism is poorly understood. IRSp53 contains a membrane-binding BAR domain followed by an unconventional CRIB motif that overlaps with a proline-rich region (CRIB-PR) and an SH3 domain that recruits actin cytoskeleton effectors. Using a fluorescence reporter assay, we show that human IRSp53 adopts a closed inactive conformation that opens synergistically with the binding of human Cdc42 to the CRIB-PR and effector proteins, such as the tumor-promoting factor Eps8, to the SH3 domain. The crystal structure of Cdc42 bound to the CRIB-PR reveals a new mode of effector binding to Rho family GTPases. Structure-inspired mutations disrupt autoinhibition and Cdc42 binding in vitro and decouple Cdc42- and IRSp53-dependent filopodia formation in cells. The data support a combinatorial mechanism of IRSp53 activation.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yadaiah Madasu
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Giorgio Scita
- 1] FIRC Institute of Molecular Oncology, Milan, Italy. [2] Department of Health Sciences, University of Milan School of Medicine, Milan, Italy
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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19
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Linkner J, Witte G, Zhao H, Junemann A, Nordholz B, Runge-Wollmann P, Lappalainen P, Faix J. The inverse BAR-domain protein IBARa drives membrane remodelling to control osmoregulation, phagocytosis and cytokinesis. J Cell Sci 2014; 127:1279-92. [DOI: 10.1242/jcs.140756] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Here, we analyzed the single I-BAR family member IBARa from D. discoideum. The X-ray structure of the N-terminal I-BAR domain solved at 2.2 Å resolution revealed an all-α helical structure that self-associates into a 165 Å zeppelin-shaped antiparallel dimer. The structural data are consistent with its shape in solution obtained by small-angle X-ray-scattering. Cosedimentation, fluorescence-anisotropy as well as fluorescence and electron microscopy revealed the I-BAR domain to bind preferentially to phosphoinositide-containing vesicles and drive the formation of negatively curved tubules. Immunofluorescence labelling further showed accumulation of endogenous IBARa at the tips of filopodia, the rim of constricting phagocytic cups, in foci connecting dividing cells during the final stage of cytokinesis, and most prominently at the osmoregulatory contractile vacuole (CV). Consistently, IBARa-null mutants displayed defects in CV formation and discharge, growth, phagocytosis and mitotic cell division, whereas filopodia formation was not compromised. Of note, IBARa-null mutants were also strongly impaired in cell spreading. Together, these data suggest IBARa to constitute an important regulator of numerous cellular processes intimately linked with the dynamic rearrangement of cellular membranes.
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20
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Lai Y, Rosenshine I, Leong JM, Frankel G. Intimate host attachment: enteropathogenic and enterohaemorrhagic Escherichia coli. Cell Microbiol 2013; 15:1796-808. [PMID: 23927593 PMCID: PMC4036124 DOI: 10.1111/cmi.12179] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/19/2013] [Accepted: 07/01/2013] [Indexed: 12/30/2022]
Abstract
Enteropathogenic and enterohaemorrhagic Escherichia coli use a novel infection strategy to colonize the gut epithelium, involving translocation of their own receptor, Tir, via a type III secretion system and subsequent formation of attaching and effecting (A/E) lesions. Following integration into the host cell plasma membrane of cultured cells, and clustering by the outer membrane adhesin intimin, Tir triggers multiple actin polymerization pathways involving host and bacterial adaptor proteins that converge on the host Arp2/3 actin nucleator. Although initially thought to be involved in A/E lesion formation, recent data have shown that the known Tir-induced actin polymerization pathways are dispensable for this activity, but can play other major roles in colonization efficiency, in vivo fitness and systemic disease. In this review we summarize the roadmap leading from the discovery of Tir, through the different actin polymerization pathways it triggers, to our current understanding of their physiological functions.
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Affiliation(s)
- YuShuan Lai
- Department of Microbiology and Physiological Systems, University of
Massachusetts Medical School, Worcester MA, USA
| | - Ilan Rosenshine
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of
Medicine, The Hebrew University of Jerusalem, Israel
| | - John M. Leong
- Department of Microbiology and Physiological Systems, University of
Massachusetts Medical School, Worcester MA, USA
- Molecular Biology and Microbiology Department, Tufts University,
Boston MA, USA
| | - Gad Frankel
- MRC Centre for Molecular Bacteriology and Infection, Imperial
College London, London, UK
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21
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Insulin receptor tyrosine kinase substrate activates EGFR/ERK signalling pathway and promotes cell proliferation of hepatocellular carcinoma. Cancer Lett 2013; 337:96-106. [PMID: 23693078 DOI: 10.1016/j.canlet.2013.05.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Revised: 05/07/2013] [Accepted: 05/14/2013] [Indexed: 11/21/2022]
Abstract
Insulin receptor tyrosine kinase substrate (IRTKS) is closely associated with actin remodelling and membrane protrusion, but its role in the pathogenesis of malignant tumours, including hepatocellular carcinoma (HCC), is still unknown. In this study, we showed that IRTKS was frequently upregulated in HCC samples, and its expression level was significantly associated with tumour size. Enforced expression of IRTKS in human HCC cell lines significantly promoted their proliferation and colony formation in vitro, and their capacity to develop tumour xenografts in vivo, whereas knockdown of IRTKS resulted in the opposite effects. Furthermore, the bromodeoxyuridine (BrdU) incorporation analyses and propidium iodide staining indicated that IRTKS can promote the entry into S phase of cell cycle progression. Significantly, IRTKS can interact with epidermal growth factor receptor (EGFR), results in the phosphorylation of extracellular signal-regulated kinase (ERK). By contrast, inhibition of ERK activation can attenuate the effects of IRTKS overexpression on cellular proliferation. Taken together, these data demonstrate that IRTKS promotes the proliferation of HCC cells by enhancing EGFR-ERK signalling pathway.
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22
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Oikawa T, Okamura H, Dietrich F, Senju Y, Takenawa T, Suetsugu S. IRSp53 mediates podosome formation via VASP in NIH-Src cells. PLoS One 2013; 8:e60528. [PMID: 23555988 PMCID: PMC3608619 DOI: 10.1371/journal.pone.0060528] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/27/2013] [Indexed: 01/07/2023] Open
Abstract
Podosomes are cellular “feet,” characterized by F-actin-rich membrane protrusions, which drive cell migration and invasion into the extracellular matrix. Small GTPases that regulate the actin cytoskeleton, such as Cdc42 and Rac are central regulators of podosome formation. The adaptor protein IRSp53 contains an I-BAR domain that deforms membranes into protrusions and binds to Rac, a CRIB motif that interacts with Cdc42, an SH3 domain that binds to many actin cytoskeletal regulators with proline-rich peptides including VASP, and the C-terminal variable region by splicing. However, the role of IRSp53 and VASP in podosome formation had been unclear. Here we found that the knockdown of IRSp53 by RNAi attenuates podosome formation and migration in Src-transformed NIH3T3 (NIH-Src) cells. Importantly, the differences in the IRSp53 C-terminal splicing isoforms did not affect podosome formation. Overexpression of IRSp53 deletion mutants suggested the importance of linking small GTPases to SH3 binding partners. Interestingly, VASP physically interacted with IRSp53 in NIH-Src cells and was essential for podosome formation. These data highlight the role of IRSp53 as a linker of small GTPases to VASP for podosome formation.
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Affiliation(s)
- Tsukasa Oikawa
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine, Sinjuku, Tokyo, Japan
| | - Hitomi Okamura
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | - Franziska Dietrich
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
- University of Duisburg-Essen, Essen, Germany
| | - Yosuke Senju
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
| | | | - Shiro Suetsugu
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Bunkyo, Tokyo, Japan
- * E-mail:
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23
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A new means to identify type 3 secreted effectors: functionally interchangeable class IB chaperones recognize a conserved sequence. mBio 2012; 3:mBio.00243-11. [PMID: 22334517 PMCID: PMC3280449 DOI: 10.1128/mbio.00243-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Many Gram-negative bacteria utilize specialized secretion systems to inject proteins (effectors) directly into host cells. Little is known regarding how bacteria ensure that only small subsets of the thousands of proteins they encode are recognized as substrates of the secretion systems, limiting their identification through bioinformatic analyses. Many of these proteins require chaperones to direct their secretion. Here, using the newly described protein interaction platform assay, we demonstrate that type 3 secretion system class IB chaperones from one bacterium directly bind their own effectors as well as those from other species. In addition, we observe that expression of class IB homologs from seven species, including pathogens and endosymbionts, mediate the translocation of effectors from Shigella directly into host cells, demonstrating that class IB chaperones are often functionally interchangeable. Notably, class IB chaperones bind numerous effectors. However, as previously proposed, they are not promiscuous; rather they recognize a defined sequence that we designate the conserved chaperone-binding domain (CCBD) sequence [(LMIF)(1)XXX(IV)(5)XX(IV)(8)X(N)(10)]. This sequence is the first defined amino acid sequence to be identified for any interspecies bacterial secretion system, i.e., a system that delivers proteins directly into eukaryotic cells. This sequence provides a new means to identify substrates of type III secretion systems. Indeed, using a pattern search algorithm for the CCBD sequence, we have identified the first two probable effectors from an endosymbiont, Sodalis glossinidius. IMPORTANCE Many Gram-negative pathogens utilize type 3 secretion systems to deliver tens of effectors into host cells. In order to understand the diverse ways that these organisms cause disease, it is necessary to identify their effectors, many of which require chaperones to be secreted. Here we establish that class IB chaperones are not promiscuous, as previously proposed, but rather recognize a conserved effector sequence. We demonstrate that pattern search algorithms based on this defined sequence can be used to identify previously unknown effectors. Furthermore, we observe that class IB chaperones from at least seven bacterial species are functionally interchangeable. Not only do they bind and mediate the delivery of their own set of effectors into host cells but they also bind to type 3 substrates from other bacteria, suggesting that inhibitors that block chaperone-effector interactions could provide a novel means to effectively treat infections due to Gram-negative pathogens, including organisms resistant to currently available antibiotics.
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24
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Lesser CF, Leong JM. Bacterial scaffolds assemble novel higher-order complexes to reengineer eukaryotic cell processes. Sci Signal 2011; 4:pe32. [PMID: 21730324 DOI: 10.1126/scisignal.2002252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Many microbial pathogens use specialized secretion systems to inject proteins referred to as effectors directly into eukaryotic host cells. These effectors directly target various eukaryotic signaling pathways and cellular processes, often by mimicking the activity of host cell proteins. Effectors of pathogenic Escherichia coli and Salmonella typhimurium can also act as molecular scaffolds that not only recruit but also directly regulate the activity and localization of multiple eukaryotic proteins. By assembling and localizing disparate signaling pathways, the bacteria can reengineer host cell processes to generate novel processes not previously observed in eukaryotic cells.
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Affiliation(s)
- Cammie F Lesser
- Department of Medicine (Microbiology and Molecular Genetics), Division of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, 65 Landsdowne Street, Cambridge, MA 02139, USA.
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