1
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Höhler M, Alcázar-Román AR, Schenk K, Aguirre-Huamani MP, Braun C, Zrieq R, Mölleken K, Hegemann JH, Fleig U. Direct targeting of host microtubule and actin cytoskeletons by a chlamydial pathogenic effector protein. J Cell Sci 2024; 137:jcs263450. [PMID: 39099397 PMCID: PMC11444262 DOI: 10.1242/jcs.263450] [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: 07/23/2024] [Accepted: 07/25/2024] [Indexed: 08/06/2024] Open
Abstract
To propagate within a eukaryotic cell, pathogenic bacteria hijack and remodulate host cell functions. The Gram-negative obligate intracellular Chlamydiaceae, which pose a serious threat to human and animal health, attach to host cells and inject effector proteins that reprogram host cell machineries. Members of the conserved chlamydial TarP family have been characterized as major early effectors that bind to and remodel the host actin cytoskeleton. We now describe a new function for the Chlamydia pneumoniae TarP member CPn0572, namely the ability to bind and alter the microtubule cytoskeleton. Thus, CPn0572 is unique in being the only prokaryotic protein that directly modulates both dynamic cytoskeletons of a eukaryotic cell. Ectopically expressed GFP-CPn0572 associates in a dose-independent manner with either cytoskeleton singly or simultaneously. In vitro, CPn0572 binds directly to microtubules. Expression of a microtubule-only CPn0572 variant resulted in the formation of an aberrantly thick, stabilized microtubule network. Intriguingly, during infection, secreted CPn0572 also colocalized with altered microtubules, suggesting that this protein also affects microtubule dynamics during infection. Our analysis points to a crosstalk between actin and microtubule cytoskeletons via chlamydial CPn0572.
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Affiliation(s)
- Mona Höhler
- Eukaryotic Microbiology, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | | | - Katharina Schenk
- Eukaryotic Microbiology, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | | | - Corinna Braun
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Rafat Zrieq
- Department of Public Health, College of Public Health and Health Informatics, University of Ha'il, Ha'il City 2440, Saudi Arabia
- Applied Science Research Centre, Applied Science Private University, Amman 11931, Jordan
| | - Katja Mölleken
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Johannes H Hegemann
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Ursula Fleig
- Eukaryotic Microbiology, Heinrich-Heine-University, 40225 Düsseldorf, Germany
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2
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Kocher F, Applegate V, Reiners J, Port A, Spona D, Hänsch S, Mirzaiebadizi A, Ahmadian MR, Smits SHJ, Hegemann JH, Mölleken K. The Chlamydia pneumoniae effector SemD exploits its host's endocytic machinery by structural and functional mimicry. Nat Commun 2024; 15:7294. [PMID: 39181890 PMCID: PMC11344771 DOI: 10.1038/s41467-024-51681-3] [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: 02/12/2024] [Accepted: 08/15/2024] [Indexed: 08/27/2024] Open
Abstract
To enter epithelial cells, the obligate intracellular pathogen Chlamydia pneumoniae secretes early effector proteins, which bind to and modulate the host-cell's plasma membrane and recruit several pivotal endocytic host proteins. Here, we present the high-resolution structure of an entry-related chlamydial effector protein, SemD. Co-crystallisation of SemD with its host binding partners demonstrates that SemD co-opts the Cdc42 binding site to activate the actin cytoskeleton regulator N-WASP, making active, GTP-bound Cdc42 superfluous. While SemD binds N-WASP much more strongly than Cdc42 does, it does not bind the Cdc42 effector protein FMNL2, indicating effector protein specificity. Furthermore, by identifying flexible and structured domains, we show that SemD can simultaneously interact with the membrane, the endocytic protein SNX9, and N-WASP. Here, we show at the structural level how a single effector protein can hijack central components of the host's endocytic system for efficient internalization.
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Affiliation(s)
- Fabienne Kocher
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Functional Microbial Genomics, Düsseldorf, Germany
| | - Violetta Applegate
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Center for Structural Studies, Düsseldorf, Germany
| | - Jens Reiners
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Center for Structural Studies, Düsseldorf, Germany
| | - Astrid Port
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Center for Structural Studies, Düsseldorf, Germany
| | - Dominik Spona
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Functional Microbial Genomics, Düsseldorf, Germany
| | - Sebastian Hänsch
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Center for Advanced Imaging, Düsseldorf, Germany
| | - Amin Mirzaiebadizi
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Mohammad Reza Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Sander H J Smits
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Center for Structural Studies, Düsseldorf, Germany
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute of Biochemistry, Düsseldorf, Germany
| | - Johannes H Hegemann
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Functional Microbial Genomics, Düsseldorf, Germany.
| | - Katja Mölleken
- Heinrich Heine University Düsseldorf, Faculty of Mathematics and Natural Sciences, Institute for Functional Microbial Genomics, Düsseldorf, Germany
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3
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Challagundla N, Phadnis D, Gupta A, Agrawal-Rajput R. Host Lipid Manipulation by Intracellular Bacteria: Moonlighting for Immune Evasion. J Membr Biol 2023; 256:393-411. [PMID: 37938349 DOI: 10.1007/s00232-023-00296-8] [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] [Received: 09/11/2023] [Accepted: 10/11/2023] [Indexed: 11/09/2023]
Abstract
Lipids are complex organic molecules that fulfill energy demands and sometimes act as signaling molecules. They are mostly found in membranes, thus playing an important role in membrane trafficking and protecting the cell from external dangers. Based on the composition of the lipids, their fluidity and charge, their interaction with embedded proteins vary greatly. Bacteria can hijack host lipids to satisfy their energy needs or to conceal themselves from host cells. Intracellular bacteria continuously exploit host, from their entry into host cells utilizing host lipid machinery to exiting through the cells. This acquisition of lipids from host cells helps in their disguise mechanism. The current review explores various mechanisms employed by the intracellular bacteria to manipulate and acquire host lipids. It discusses their role in manipulating host membranes and the subsequence impact on the host cells. Modulating these lipids in macrophages not only serve the purpose of the pathogen but also modulates the macrophage energy metabolism and functional state. Additionally, we have explored the intricate pathogenic relationship and the potential prospects of using this knowledge in lipid-based therapeutics to disrupt pathogen dominance.
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Affiliation(s)
- Naveen Challagundla
- Immunology Lab, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar, Gujarat, 382426, India
| | - Deepti Phadnis
- Immunology Lab, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar, Gujarat, 382426, India
| | - Aakriti Gupta
- Immunology Lab, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar, Gujarat, 382426, India
| | - Reena Agrawal-Rajput
- Immunology Lab, Indian Institute of Advanced Research, Koba Institutional Area, Gandhinagar, Gujarat, 382426, India.
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4
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Spona D, Hanisch PT, Hegemann JH, Mölleken K. A single chlamydial protein reshapes the plasma membrane and serves as recruiting platform for central endocytic effector proteins. Commun Biol 2023; 6:520. [PMID: 37179401 PMCID: PMC10182996 DOI: 10.1038/s42003-023-04913-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Uptake of obligate intracellular bacterial pathogens into mammalian epithelial cells is critically dependent on modulation of the host's endocytic machinery. It is an open question how the invading pathogens generate a membrane-bound vesicle appropriate to their size. This requires extensive deformation of the host plasma membrane itself by pathogen-derived membrane-binding proteins, accompanied by substantial F-actin-based forces to further expand and finally pinch off the vesicle. Here we show that upon adhesion to the host cell, the human pathogenic bacterium Chlamydia pneumoniae secretes the scaffolding effector protein CPn0677, which binds to the inner leaflet of the invaginating host's PM, induces inwardly directed, negative membrane curvature, and forms a recruiting platform for the membrane-deforming BAR-domain containing proteins Pacsin and SNX9. In addition, while bound to the membrane, CPn0677 recruits monomeric G-actin, and its C-terminal region binds and activates N-WASP, which initiates branching actin polymerization via the Arp2/3 complex. Together, these membrane-bound processes enable the developing endocytic vesicle to engulf the infectious elementary body, while the associated actin network generates the forces required to reshape and detach the nascent vesicle from the PM. Thus, Cpn0677 (now renamed SemD) acts as recruiting platform for central components of the endocytic machinery during uptake of chlamydia.
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Affiliation(s)
- Dominik Spona
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Philipp T Hanisch
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Johannes H Hegemann
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Katja Mölleken
- Institute for Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany.
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5
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Kostow N, Welch MD. Manipulation of host cell plasma membranes by intracellular bacterial pathogens. Curr Opin Microbiol 2023; 71:102241. [PMID: 36442349 PMCID: PMC10074913 DOI: 10.1016/j.mib.2022.102241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/20/2022] [Accepted: 10/31/2022] [Indexed: 11/26/2022]
Abstract
Manipulation of the host cell plasma membrane is critical during infection by intracellular bacterial pathogens, particularly during bacterial entry into and exit from host cells. To manipulate host cells, bacteria deploy secreted proteins that modulate or modify host cell components. Here, we review recent advances that suggest common themes by which bacteria manipulate the host cell plasma membrane. One theme is that bacteria use diverse strategies to target or influence host cell plasma membrane composition and shape. A second theme is that bacteria take advantage of host cell plasma membrane-associated pathways such as signal transduction, endocytosis, and exocytosis. Future investigation into how bacterial and host factors contribute to plasma membrane manipulation by bacterial pathogens will reveal new insights into pathogenesis and fundamental principles of plasma membrane biology.
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Affiliation(s)
- Nora Kostow
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
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6
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VpdC is a ubiquitin-activated phospholipase effector that regulates Legionella vacuole expansion during infection. Proc Natl Acad Sci U S A 2022; 119:e2209149119. [PMID: 36413498 PMCID: PMC9860323 DOI: 10.1073/pnas.2209149119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Intravacuolar pathogens need to gradually expand their surrounding vacuole to accommodate the growing number of bacterial offspring during intracellular replication. Here we found that Legionella pneumophila controls vacuole expansion by fine-tuning the generation of lysophospholipids within the vacuolar membrane. Upon allosteric activation by binding to host ubiquitin, the type IVB (Dot/Icm) effector VpdC converts phospholipids into lysophospholipids which, at moderate concentrations, are known to promote membrane fusion but block it at elevated levels by generating excessive positive membrane curvature. Consequently, L. pneumophila overproducing VpdC were prevented from adequately expanding their surrounding membrane, trapping the replicating bacteria within spatially confined vacuoles and reducing their capability to proliferate intracellularly. Quantitative lipidomics confirmed a VpdC-dependent increase in several types of lysophospholipids during infection, and VpdC production in transiently transfected cells caused tubulation of organelle membranes as well as mitochondria fragmentation, processes that can be phenocopied by supplying cells with exogenous lysophospholipids. Together, these results demonstrate an important role for bacterial phospholipases in vacuolar expansion.
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7
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Keb G, Ferrell J, Scanlon KR, Jewett TJ, Fields KA. Chlamydia trachomatis TmeA Directly Activates N-WASP To Promote Actin Polymerization and Functions Synergistically with TarP during Invasion. mBio 2021; 12:e02861-20. [PMID: 33468693 PMCID: PMC7845632 DOI: 10.1128/mbio.02861-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/25/2020] [Indexed: 12/19/2022] Open
Abstract
Chlamydia trachomatis is a medically significant human pathogen and is an epithelial-tropic obligate intracellular parasite. Invasion of nonprofessional phagocytes represents a crucial step in the infection process and has likely promoted the evolution of a redundant mechanism and routes of entry. Like many other viral and invasive bacterial pathogens, manipulation of the host cell cytoskeleton represents a focal point in Chlamydia entry. The advent of genetic techniques in C. trachomatis, such as creation of complete gene deletions via fluorescence-reported allelic exchange mutagenesis (FRAEM), is providing important tools to unravel the contributions of bacterial factors in these complex pathways. The type III secretion chaperone Slc1 directs delivery of at least four effectors during the invasion process. Two of these, TarP and TmeA, have been associated with manipulation of actin networks and are essential for normal levels of invasion. The functions of TarP are well established, whereas TmeA is less well characterized. We leverage chlamydial genetics and proximity labeling here to provide evidence that TmeA directly targets host N-WASP to promote Arp2/3-dependent actin polymerization. Our work also shows that TmeA and TarP influence separate, yet synergistic pathways to accomplish chlamydial entry. These data further support an appreciation that a pathogen, confined by a reductionist genome, retains the ability to commit considerable resources to accomplish bottle-neck steps during the infection process.IMPORTANCE The increasing genetic tractability of Chlamydia trachomatis is accelerating the ability to characterize the unique infection biology of this obligate intracellular parasite. These efforts are leading to a greater understanding of the molecular events associated with key virulence requirements. Manipulation of the host actin cytoskeleton plays a pivotal role throughout Chlamydia infection, yet a thorough understanding of the molecular mechanisms initiating and orchestrating actin rearrangements has lagged. Our work highlights the application of genetic manipulation to address open questions regarding chlamydial invasion, a process essential to survival. We provide definitive insight regarding the role of the type III secreted effector TmeA and how that activity relates to another prominent effector, TarP. In addition, our data implicate at least one source that contributes to the functional divergence of entry mechanisms among chlamydial species.
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Affiliation(s)
- Gabrielle Keb
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Joshua Ferrell
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Kaylyn R Scanlon
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Travis J Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
| | - Kenneth A Fields
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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8
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Hanford HE, Von Dwingelo J, Abu Kwaik Y. Bacterial nucleomodulins: A coevolutionary adaptation to the eukaryotic command center. PLoS Pathog 2021; 17:e1009184. [PMID: 33476322 PMCID: PMC7819608 DOI: 10.1371/journal.ppat.1009184] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Through long-term interactions with their hosts, bacterial pathogens have evolved unique arsenals of effector proteins that interact with specific host targets and reprogram the host cell into a permissive niche for pathogen proliferation. The targeting of effector proteins into the host cell nucleus for modulation of nuclear processes is an emerging theme among bacterial pathogens. These unique pathogen effector proteins have been termed in recent years as "nucleomodulins." The first nucleomodulins were discovered in the phytopathogens Agrobacterium and Xanthomonas, where their nucleomodulins functioned as eukaryotic transcription factors or integrated themselves into host cell DNA to promote tumor induction, respectively. Numerous nucleomodulins were recently identified in mammalian pathogens. Bacterial nucleomodulins are an emerging family of pathogen effector proteins that evolved to target specific components of the host cell command center through various mechanisms. These mechanisms include: chromatin dynamics, histone modification, DNA methylation, RNA splicing, DNA replication, cell cycle, and cell signaling pathways. Nucleomodulins may induce short- or long-term epigenetic modifications of the host cell. In this extensive review, we discuss the current knowledge of nucleomodulins from plant and mammalian pathogens. While many nucleomodulins are already identified, continued research is instrumental in understanding their mechanisms of action and the role they play during the progression of pathogenesis. The continued study of nucleomodulins will enhance our knowledge of their effects on nuclear chromatin dynamics, protein homeostasis, transcriptional landscapes, and the overall host cell epigenome.
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Affiliation(s)
- Hannah E. Hanford
- Department of Microbiology and Immunology, University of Louisville, Kentucky, United States of America
| | - Juanita Von Dwingelo
- Department of Microbiology and Immunology, University of Louisville, Kentucky, United States of America
| | - Yousef Abu Kwaik
- Department of Microbiology and Immunology, University of Louisville, Kentucky, United States of America
- Center for Predicative Medicine, College of Medicine, University of Louisville, Kentucky, United States of America
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9
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Braun C, Hegemann JH, Mölleken K. Insights Into a Chlamydia pneumoniae-Specific Gene Cluster of Membrane Binding Proteins. Front Cell Infect Microbiol 2020; 10:565808. [PMID: 33194804 PMCID: PMC7609445 DOI: 10.3389/fcimb.2020.565808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/23/2020] [Indexed: 11/18/2022] Open
Abstract
Chlamydia pneumoniae is an obligate intracellular pathogen that causes diseases of the upper and lower respiratory tract and is linked to a number of severe and chronic conditions. Here, we describe a large, C. pneumoniae-specific cluster of 13 genes (termed mbp1-13) that encode highly homologous chlamydial proteins sharing the capacity to bind to membranes. The gene cluster is localized on the chromosome between the highly diverse adhesin-encoding pmp genes pmp15 and pmp14. Comparison of human clinical isolates to the predicted ancestral koala isolate indicates that the cluster was acquired in the ancestor and was adapted / modified during evolution. SNPs and IN/DELs within the cluster are specific to isolates taken from different human tissues and show an ongoing adaptation. Most of the cluster proteins harbor one or two domains of unknown function (DUF575 and DUF562). During ectopic expression in human cells these DUF domains are crucial for the association of cluster proteins to the endo-membrane system. Especially DUF575 which harbors a predicted transmembrane domain is important for binding to the membrane, while presence of the DUF562 seems to be of regulatory function. For Mbp1, founding member of the cluster that exhibits a very limited sequence identity to the human Rab36 protein, we found a specific binding to vesicles carrying the early endosomal marker PtdIns(3)P and the endosomal Rab GTPases Rab11 and Rab14. This binding is dependent on a predicted transmembrane domain with an α-helical / β-strand secondary structure, as the mutant version Mbp1mut, which lacks the β-strand secondary structure, shows a reduced association to PtdIns(3)P-positive membranes carrying Rab11 and Rab14. Furthermore, we could not only show that Mbp1 associates with Rab36, but found this specific Rab protein to be recruited to the early C. pneumoniae inclusion. Detection of endogenous Mbp1 and Mbp4 reveal a colocalization to the chlamydial outer membrane protein Momp on EBs. The same colocalization pattern with Momp was observed when we ectopically expressed Mbp4 in C. trachomatis. Thus, we identified a C. pneumoniae-specific cluster of 13 membrane binding proteins (Mbps) localizing to the bacterial outer membrane system.
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Affiliation(s)
- Corinna Braun
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Johannes H Hegemann
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
| | - Katja Mölleken
- Institute of Functional Microbial Genomics, Heinrich-Heine-University, Düsseldorf, Germany
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10
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Shen AW, Fu LL, Lin L, Sun B, Song DX, Wang WT, Wang YH, Yin PR, Yu SQ. SNX9 Inhibits Cell Proliferation and Cyst Development in Autosomal Dominant Polycystic Kidney Disease via Activation of the Hippo-YAP Signaling Pathway. Front Cell Dev Biol 2020; 8:811. [PMID: 32974348 PMCID: PMC7472854 DOI: 10.3389/fcell.2020.00811] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/31/2020] [Indexed: 12/29/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a complex process, involving the alteration of multiple genes and signaling pathways, and the pathogenesis of ADPKD remains largely unknown. Here, we demonstrated the suppressive role of sorting nexin 9 (SNX9) during ADPKD development. Sorting nexin 9 expression was detected in the kidney tissues of ADPKD patients, for the first time, and SNX9 expression was also detected in Pkd1 knockout (Pkd1–/–) and control mice. Subsequently, a series of gain- and loss-of-function studies were performed, to explore the biological roles and underlying molecular mechanisms of SNX9 in ADPKD progression. The expression of SNX9 was significantly downregulated in ADPKD patients and Pkd1–/– mice compared with control individuals and wild-type mice (Pkd1+/+), respectively. The ectopic expression of SNX9 significantly inhibited ADPKD cell proliferation, renal cyst formation and enlargement, whereas these effects were promoted by SNX9 silencing. Mechanistically, we found that SNX9 interacted directly with yes-associated protein (YAP) and increased the large tumor suppressor kinase 1-mediated phosphorylation of YAP, resulting in the cytoplasmic retention of YAP, the decreased transcriptional activity of the YAP/TEA domain transcription factor 4 complex, and, consequently, the inhibition of Hippo target gene expression and ADPKD development. Taken together, our findings provided novel insights into the role played by SNX9 during ADPKD pathogenesis and may reveal novel therapeutic approaches for ADPKD and related kidney diseases.
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Affiliation(s)
- Ai-Wen Shen
- Department of Nephrology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Li-Li Fu
- Department of Nephrology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Lu Lin
- Division of Nephrology, Department of Medicine, The 5th Hospital of Sun Yat-sen University1, Zhuhai, China
| | - Bo Sun
- Department of Nephrology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Dong-Xu Song
- Department of Nephrology, Second People's Hospital of Fuyang City, Fuyang, China
| | - Wu-Tao Wang
- Department of Nephrology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Yi-Hao Wang
- Department of Nephrology, Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Pei-Ran Yin
- Department of Nephrology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Sheng-Qiang Yu
- Department of Nephrology, Changzheng Hospital, Naval Medical University, Shanghai, China
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11
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Ji Z, Su J, Hou Y, Yao Z, Yu B, Zhang X. EGFR/FAK and c-Src signalling pathways mediate the internalisation of Staphylococcus aureus by osteoblasts. Cell Microbiol 2020; 22:e13240. [PMID: 32584493 DOI: 10.1111/cmi.13240] [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] [Received: 01/22/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 01/18/2023]
Abstract
Internalisation of Staphylococcus aureus in osteoblasts plays a critical role in the persistence and recurrence of osteomyelitis, the mechanisms involved in this process remain largely unknown. In the present study, evidence of internalised S. aureus in osteoblasts was found in long bone of haematogenous osteomyelitis in mice after 2 weeks of infection. Meanwhile, eliminating extracellular S. aureus by gentamicin can partially rescue bone loss, whereas the remaining intracellular S. aureus in osteoblasts may be associated with continuous bone destruction. In osteoblastic MC3T3 cells, intracellular S. aureus was detectable as early as 15 min after infection, and the internalisation rates increased with the extension of infection time. Additionally, S. aureus invasion stimulated the expression of phosphor-focal adhesion kinase (FAK), phosphor-epidermal growth factor receptor (EGFR) and phosphor-c-Src in a time-dependent way, and blocking EGFR/FAK or c-Src signalling significantly reduced the internalisation rate of S. aureus in osteoblasts. Our findings provide new insights into the mechanism of S. aureus internalisation in osteoblast and raise the potential of targeting EGFR/FAK and c-Src as adjunctive therapeutics for treating chronic S. aureus osteomyelitis.
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Affiliation(s)
- Zhiguo Ji
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jianwen Su
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yilong Hou
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zilong Yao
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Bin Yu
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Xianrong Zhang
- Division of Orthopaedics and Traumatology, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Bone and Cartilage Regenerative Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, China
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12
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Bend out of shape. Nat Rev Microbiol 2020; 18:192-193. [PMID: 32081884 DOI: 10.1038/s41579-020-0339-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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