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Wenbo L, Yewei Y, Hui Z, Zhongyu L. Hijacking host cell vesicular transport: New insights into the nutrient acquisition mechanism of Chlamydia. Virulence 2024; 15:2351234. [PMID: 38773735 PMCID: PMC11123459 DOI: 10.1080/21505594.2024.2351234] [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: 07/26/2023] [Accepted: 04/27/2024] [Indexed: 05/24/2024] Open
Abstract
Chlamydia infection is an important cause of public health diseases, and no effective vaccine is currently available. Owing to its unique intracellular lifestyle, Chlamydia requires a variety of nutrients and substrates from host cells, particularly sphingomyelin, cholesterol, iron, amino acids, and the mannose-6-phosphate receptor, which are essential for inclusion development. Here, we summarize the recent advances in Chlamydia nutrient acquisition mechanism by hijacking host cell vesicular transport, which plays an important role in chlamydial growth and development. Chlamydia obtains the components necessary to complete its intracellular developmental cycle by recruiting Rab proteins (major vesicular trafficking regulators) and Rab effector proteins to the inclusion, interfering with Rab-mediated multivesicular trafficking, reorienting the nutrition of host cells, and reconstructing the intracellular niche environment. Consequently, exploring the role of vesicular transport in nutrient acquisition offers a novel perspective on new approaches for preventing and treating Chlamydia infection.
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Affiliation(s)
- Lei Wenbo
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang Medical School, University of South China, Hengyang, Hunan, P.R. China
- Department of Clinical Laboratory Medicine, Institution of Microbiology and Infectious Diseases, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, P.R. China
| | - Yang Yewei
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang Medical School, University of South China, Hengyang, Hunan, P.R. China
| | - Zhou Hui
- Department of Laboratory Medicine and Pathology, First Affiliated Hospital of Hunan University of Chinese Traditional Medicine, Changsha, Hunan, P.R. China
| | - Li Zhongyu
- Institute of Pathogenic Biology, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hengyang Medical School, University of South China, Hengyang, Hunan, P.R. China
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2
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Pang Y, Shui J, Li C, Li Y, Chen H, Tang S. The serodiagnositic value of Chlamydia trachomatis antigens in antibody detection using luciferase immunosorbent assay. Front Public Health 2024; 12:1333559. [PMID: 38476494 PMCID: PMC10927828 DOI: 10.3389/fpubh.2024.1333559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 02/14/2024] [Indexed: 03/14/2024] Open
Abstract
Introduction Among the different antigens used in the detection of anti-Chlamydia trachomatis antibodies, significant differences in sensitivity and specificity have been observed. Further evaluation of C. trachomatis antigens in antibody detection is urgently needed for the development and application of C. trachomatis serologic assays. Methods Chlamydia trachomatis antigens Pgp3, TmeA, InaC, and HSP60 were selected and used in luciferase immunosorbent assay (LISA). The detection results obtained from well-defined C. trachomatis positive and negative samples were compared with the commercial C. trachomatis ELISA (Mikrogen) for performance evaluation. Results Pgp3, TmeA, InaC, and HSP60-based LISA showed sensitivity of 92.8, 88.8, 90.4, and 94.4%, and specificity of 99.2, 99.2, 99.2, and 92%, respectively. ROC analysis indicated that Pgp3-based LISA showed similar performance to Mikrogen ELISA (AUC 0.986 vs. 0.993, p = 0.207). Furthermore, four C. trachomatis antigens achieved strong diagnostic efficiency, i.e., positive likelihood ratios [+LR] ≥ 10 in C. trachomatis-infected women and negative likelihood ratios [-LR] ≤ 0.1 in C. trachomatis negative low exposure risk children, but only Pgp3 and TmeA showed strong diagnostic value in general adults. In addition, Pgp3, TmeA, and InaC, but not HSP60, achieved high performance, i.e., both positive predictive value (PPV) and negative predictive value (NPV) ≥ 90.9%, and showed no significant cross-reactivity with anti-Chlamydiapneumoniae. Conclusion Three C. trachomatis species-specific antigens Pgp3, TmeA, and InaC show superior performance in the detection of anti-C. trachomatis antibody, indicating the potential to be used in developing C. trachomatis serologic tests.
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Affiliation(s)
- Yulian Pang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | - Jingwei Shui
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
- Department of Emergency, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, China
| | - Changchang Li
- Dermatology Hospital of Southern Medical University, Guangzhou, China
| | - Yongzhi Li
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
| | | | - Shixing Tang
- Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China
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3
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Bastidas RJ, Kędzior M, Davidson RK, Walsh SC, Dolat L, Sixt BS, Pruneda JN, Coers J, Valdivia RH. The acetylase activity of Cdu1 regulates bacterial exit from infected cells by protecting Chlamydia effectors from degradation. eLife 2024; 12:RP87386. [PMID: 38358795 PMCID: PMC10942603 DOI: 10.7554/elife.87386] [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: 02/16/2024] Open
Abstract
Many cellular processes are regulated by ubiquitin-mediated proteasomal degradation. Pathogens can regulate eukaryotic proteolysis through the delivery of proteins with de-ubiquitinating (DUB) activities. The obligate intracellular pathogen Chlamydia trachomatis secretes Cdu1 (ChlaDUB1), a dual deubiquitinase and Lys-acetyltransferase, that promotes Golgi remodeling and survival of infected host cells presumably by regulating the ubiquitination of host and bacterial proteins. Here, we determined that Cdu1's acetylase but not its DUB activity is important to protect Cdu1 from ubiquitin-mediated degradation. We further identified three C. trachomatis proteins on the pathogen-containing vacuole (InaC, IpaM, and CTL0480) that required Cdu1's acetylase activity for protection from degradation and determined that Cdu1 and these Cdu1-protected proteins are required for optimal egress of Chlamydia from host cells. These findings highlight a non-canonical mechanism of pathogen-mediated protection of virulence factors from degradation after their delivery into host cells and the coordinated regulation of secreted effector proteins.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Mateusz Kędzior
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Robert K Davidson
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Stephen C Walsh
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Lee Dolat
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
| | - Barbara S Sixt
- Deparment of Molecular Biology, Umeå UniversityUmeåSweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå UniversityUmeåSweden
- Umeå Centre for Microbial Research (UCMR), Umeå UniversityUmeåSweden
| | - Jonathan N Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science UniversityPortlandUnited States
| | - Jorn Coers
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke UniversityDurhamUnited States
- Department of Molecular Genetics and Microbiology, Duke UniversityDukeUnited States
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4
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Chang YY, Valenzuela C, Lensen A, Lopez-Montero N, Sidik S, Salogiannis J, Enninga J, Rohde J. Microtubules provide force to promote membrane uncoating in vacuolar escape for a cyto-invasive bacterial pathogen. Nat Commun 2024; 15:1065. [PMID: 38316786 PMCID: PMC10844605 DOI: 10.1038/s41467-024-45182-6] [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: 03/30/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Intracellular bacterial pathogens gain entry to mammalian cells inside a vacuole derived from the host membrane. Some of them escape the bacteria-containing vacuole (BCV) and colonize the cytosol. Bacteria replicating within BCVs coopt the microtubule network to position it within infected cells, whereas the role of microtubules for cyto-invasive pathogens remains obscure. Here, we show that the microtubule motor cytoplasmic dynein-1 and specific activating adaptors are hijacked by the enterobacterium Shigella flexneri. These host proteins were found on infection-associated macropinosomes (IAMs) formed during Shigella internalization. We identified Rab8 and Rab13 as mediators of dynein recruitment and discovered that the Shigella effector protein IpaH7.8 promotes Rab13 retention on moving BCV membrane remnants, thereby facilitating membrane uncoating of the Shigella-containing vacuole. Moreover, the efficient unpeeling of BCV remnants contributes to a successful intercellular spread. Taken together, our work demonstrates how a bacterial pathogen subverts the intracellular transport machinery to secure a cytosolic niche.
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Affiliation(s)
- Yuen-Yan Chang
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Camila Valenzuela
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Arthur Lensen
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Noelia Lopez-Montero
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France
| | - Saima Sidik
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada
| | - John Salogiannis
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, USA
| | - Jost Enninga
- Dynamics of Host-Pathogen Interactions Unit, Institut Pasteur, and CNRS UMR 3691 Université de Paris Cité, Paris, France.
| | - John Rohde
- Department of Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
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5
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Walker FC, Derré I. Contributions of diverse models of the female reproductive tract to the study of Chlamydia trachomatis-host interactions. Curr Opin Microbiol 2024; 77:102416. [PMID: 38103413 PMCID: PMC10922760 DOI: 10.1016/j.mib.2023.102416] [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: 09/21/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/19/2023]
Abstract
Chlamydia trachomatis is a common cause of sexually transmitted infections in humans with devastating sequelae. Understanding of disease on all scales, from molecular details to the immunology underlying pathology, is essential for identifying new ways of preventing and treating chlamydia. Infection models of various complexity are essential to understand all aspects of chlamydia pathogenesis. Cell culture systems allow for research into molecular details of infection, including characterization of the unique biphasic Chlamydia developmental cycle and the role of type-III-secreted effectors in modifying the host environment to allow for infection. Multicell type and organoid culture provide means to investigate how cells other than the infected cells contribute to the control of infection. Emerging comprehensive three-dimensional biomimetic systems may fill an important gap in current models to provide information on complex phenotypes that cannot be modeled in simpler in vitro models.
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Affiliation(s)
- Forrest C Walker
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America.
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Bastidas RJ, Kędzior M, Davidson RK, Walsh SC, Dolat L, Sixt BS, Pruneda JN, Coers J, Valdivia RH. The acetylase activity of Cdu1 regulates bacterial exit from infected cells by protecting Chlamydia effectors from degradation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.28.530337. [PMID: 36909574 PMCID: PMC10002621 DOI: 10.1101/2023.02.28.530337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Many cellular processes are regulated by ubiquitin-mediated proteasomal degradation. Pathogens can regulate eukaryotic proteolysis through the delivery of proteins with de-ubiquitinating (DUB) activities. The obligate intracellular pathogen Chlamydia trachomatis secretes Cdu1 (ChlaDUB1), a dual deubiquitinase and Lys-acetyltransferase, that promotes Golgi remodeling and survival of infected host cells presumably by regulating the ubiquitination of host and bacterial proteins. Here we determined that Cdu1's acetylase but not its DUB activity is important to protect Cdu1 from ubiquitin-mediated degradation. We further identified three C. trachomatis proteins on the pathogen-containing vacuole (InaC, IpaM, and CTL0480) that required Cdu1's acetylase activity for protection from degradation and determined that Cdu1 and these Cdu1-protected proteins are required for optimal egress of Chlamydia from host cells. These findings highlight a non-canonical mechanism of pathogen-mediated protection of virulence factors from degradation after their delivery into host cells and the coordinated regulation of secreted effector proteins.
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Affiliation(s)
- Robert J. Bastidas
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Mateusz Kędzior
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Robert K. Davidson
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Stephen C. Walsh
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Lee Dolat
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
| | - Barbara S. Sixt
- Deparment of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Jonathan N. Pruneda
- Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Jörn Coers
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
| | - Raphael H. Valdivia
- Department of Integrative Immunobiology, Duke University, Durham, N.C 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University, Durham, N.C 27708, USA
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7
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Jury B, Fleming C, Huston WM, Luu LDW. Molecular pathogenesis of Chlamydia trachomatis. Front Cell Infect Microbiol 2023; 13:1281823. [PMID: 37920447 PMCID: PMC10619736 DOI: 10.3389/fcimb.2023.1281823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023] Open
Abstract
Chlamydia trachomatis is a strict intracellular human pathogen. It is the main bacterial cause of sexually transmitted infections and the etiologic agent of trachoma, which is the leading cause of preventable blindness. Despite over 100 years since C. trachomatis was first identified, there is still no vaccine. However in recent years, the advancement of genetic manipulation approaches for C. trachomatis has increased our understanding of the molecular pathogenesis of C. trachomatis and progress towards a vaccine. In this mini-review, we aimed to outline the factors related to the developmental cycle phase and specific pathogenesis activity of C. trachomatis in order to focus priorities for future genetic approaches. We highlight the factors known to be critical for developmental cycle stages, gene expression regulatory factors, type III secretion system and their effectors, and individual virulence factors with known impacts.
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Affiliation(s)
- Brittany Jury
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Charlotte Fleming
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | | | - Laurence Don Wai Luu
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
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8
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Abstract
Type III secretion systems (T3SSs) are utilized by Gram-negative pathogens to enhance their pathogenesis. This secretion system is associated with the delivery of effectors through a needle-like structure from the bacterial cytosol directly into a target eukaryotic cell. These effector proteins then manipulate specific eukaryotic cell functions to benefit pathogen survival within the host. The obligate intracellular pathogens of the family Chlamydiaceae have a highly evolutionarily conserved nonflagellar T3SS that is an absolute requirement for their survival and propagation within the host with about one-seventh of the genome dedicated to genes associated with the T3SS apparatus, chaperones, and effectors. Chlamydiae also have a unique biphasic developmental cycle where the organism alternates between an infectious elementary body (EB) and replicative reticulate body (RB). T3SS structures have been visualized on both EBs and RBs. And there are effector proteins that function at each stage of the chlamydial developmental cycle, including entry and egress. This review will discuss the history of the discovery of chlamydial T3SS and the biochemical characterization of components of the T3SS apparatus and associated chaperones in the absence of chlamydial genetic tools. These data will be contextualized into how the T3SS apparatus functions throughout the chlamydial developmental cycle and the utility of heterologous/surrogate models to study chlamydial T3SS. Finally, there will be a targeted discussion on the history of chlamydial effectors and recent advances in the field.
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Affiliation(s)
- Elizabeth A. Rucks
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Durham Research Center II, Omaha, Nebraska, USA
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9
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Clemente TM, Angara RK, Gilk SD. Establishing the intracellular niche of obligate intracellular vacuolar pathogens. Front Cell Infect Microbiol 2023; 13:1206037. [PMID: 37645379 PMCID: PMC10461009 DOI: 10.3389/fcimb.2023.1206037] [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: 04/14/2023] [Accepted: 07/21/2023] [Indexed: 08/31/2023] Open
Abstract
Obligate intracellular pathogens occupy one of two niches - free in the host cell cytoplasm or confined in a membrane-bound vacuole. Pathogens occupying membrane-bound vacuoles are sequestered from the innate immune system and have an extra layer of protection from antimicrobial drugs. However, this lifestyle presents several challenges. First, the bacteria must obtain membrane or membrane components to support vacuole expansion and provide space for the increasing bacteria numbers during the log phase of replication. Second, the vacuole microenvironment must be suitable for the unique metabolic needs of the pathogen. Third, as most obligate intracellular bacterial pathogens have undergone genomic reduction and are not capable of full metabolic independence, the bacteria must have mechanisms to obtain essential nutrients and resources from the host cell. Finally, because they are separated from the host cell by the vacuole membrane, the bacteria must possess mechanisms to manipulate the host cell, typically through a specialized secretion system which crosses the vacuole membrane. While there are common themes, each bacterial pathogen utilizes unique approach to establishing and maintaining their intracellular niches. In this review, we focus on the vacuole-bound intracellular niches of Anaplasma phagocytophilum, Ehrlichia chaffeensis, Chlamydia trachomatis, and Coxiella burnetii.
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Affiliation(s)
| | | | - Stacey D. Gilk
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
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10
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Bastidas RJ, Valdivia RH. The emerging complexity of Chlamydia trachomatis interactions with host cells as revealed by molecular genetic approaches. Curr Opin Microbiol 2023; 74:102330. [PMID: 37247566 PMCID: PMC10988583 DOI: 10.1016/j.mib.2023.102330] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 04/24/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Chlamydia trachomatis (Ct) is an intracellular bacterial pathogen that relies on the activity of secreted proteins known as effectors to promote replication and avoidance of immune clearance. Understanding the contribution of Ct effectors to pathogenesis has proven to be challenging, given that these proteins often perform multiple functions during intracellular infection. Recent advances in molecular genetic analysis of Ct have provided valuable insights into the multifaceted nature of secreted effector proteins and their impact on the interaction between Ct and host cells and tissues. This review highlights significant findings from genetic analysis of Ct effector functions, shedding light on their diverse roles. We also discuss the challenges faced in this field of study and explore potential opportunities for further research.
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Affiliation(s)
- Robert J Bastidas
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Raphael H Valdivia
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, NC 27710, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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11
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Wevers C, Höhler M, Alcázar-Román AR, Hegemann JH, Fleig U. A Functional Yeast-Based Screen Identifies the Host Microtubule Cytoskeleton as a Target of Numerous Chlamydia pneumoniae Proteins. Int J Mol Sci 2023; 24:ijms24087618. [PMID: 37108781 PMCID: PMC10142024 DOI: 10.3390/ijms24087618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Bacterial pathogens have evolved intricate ways to manipulate the host to support infection. Here, we systematically assessed the importance of the microtubule cytoskeleton for infection by Chlamydiae, which are obligate intracellular bacteria that are of great importance for human health. The elimination of microtubules in human HEp-2 cells prior to C. pneumoniae infection profoundly attenuated the infection efficiency, demonstrating the need for microtubules for the early infection processes. To identify microtubule-modulating C. pneumoniae proteins, a screen in the model yeast Schizosaccharomyces pombe was performed. Unexpectedly, among 116 selected chlamydial proteins, more than 10%, namely, 13 proteins, massively altered the yeast interphase microtubule cytoskeleton. With two exceptions, these proteins were predicted to be inclusion membrane proteins. As proof of principle, we selected the conserved CPn0443 protein, which caused massive microtubule instability in yeast, for further analysis. CPn0443 bound and bundled microtubules in vitro and co-localized partially with microtubules in vivo in yeast and human cells. Furthermore, CPn0443-transfected U2OS cells had a significantly reduced infection rate by C. pneumoniae EBs. Thus, our yeast screen identified numerous proteins encoded using the highly reduced C. pneumoniae genome that modulated microtubule dynamics. Hijacking of the host microtubule cytoskeleton must be a vital part of chlamydial infection.
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Affiliation(s)
- Carolin Wevers
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Mona Höhler
- Eukaryotic Microbiology, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Abel R Alcázar-Román
- Eukaryotic Microbiology, 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, Institute of Functional Microbial Genomics, Heinrich-Heine-University, 40225 Düsseldorf, Germany
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Luís MP, Pereira IS, Bugalhão JN, Simões CN, Mota C, Romão MJ, Mota LJ. The Chlamydia trachomatis IncM Protein Interferes with Host Cell Cytokinesis, Centrosome Positioning, and Golgi Distribution and Contributes to the Stability of the Pathogen-Containing Vacuole. Infect Immun 2023; 91:e0040522. [PMID: 36877064 PMCID: PMC10112248 DOI: 10.1128/iai.00405-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 02/13/2023] [Indexed: 03/07/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterial pathogen that causes ocular and urogenital infections in humans. The ability of C. trachomatis to grow intracellularly in a pathogen-containing vacuole (known as an inclusion) depends on chlamydial effector proteins transported into the host cell by a type III secretion system. Among these effectors, several inclusion membrane proteins (Incs) insert in the vacuolar membrane. Here, we show that human cell lines infected by a C. trachomatis strain deficient for Inc CT288/CTL0540 (renamed IncM) displayed less multinucleation than when infected by IncM-producing strains (wild type or complemented). This indicated that IncM is involved in the ability of Chlamydia to inhibit host cell cytokinesis. The capacity of IncM to induce multinucleation in infected cells was shown to be conserved among its chlamydial homologues and appeared to require its two larger regions predicted to be exposed to the host cell cytosol. C. trachomatis-infected cells also displayed IncM-dependent defects in centrosome positioning, Golgi distribution around the inclusion, and morphology and stability of the inclusion. The altered morphology of inclusions containing IncM-deficient C. trachomatis was further affected by depolymerization of host cell microtubules. This was not observed after depolymerization of microfilaments, and inclusions containing wild-type C. trachomatis did not alter their morphology upon depolymerization of microtubules. Overall, these findings suggest that IncM may exert its effector function by acting directly or indirectly on host cell microtubules.
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Affiliation(s)
- Maria Pequito Luís
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Inês Serrano Pereira
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Joana N. Bugalhão
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Catarina N. Simões
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Cristiano Mota
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Chemistry, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Maria João Romão
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Chemistry, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - Luís Jaime Mota
- Associate Laboratory i4HB, Institute for Health and Bioeconomy, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
- Department of Life Sciences, UCIBIO, Applied Molecular Biosciences Unit, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
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In Search of a Mechanistic Link between Chlamydia trachomatis-Induced Cellular Pathophysiology and Oncogenesis. Infect Immun 2023; 91:e0044322. [PMID: 36695575 PMCID: PMC9933725 DOI: 10.1128/iai.00443-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Centrosome duplication and cell cycle progression are essential cellular processes that must be tightly controlled to ensure cellular integrity. Despite their complex regulatory mechanisms, microbial pathogens have evolved sophisticated strategies to co-opt these processes to promote infection. While misregulation of these processes can greatly benefit the pathogen, the consequences to the host cell can be devastating. During infection, the obligate intracellular pathogen Chlamydia trachomatis induces gross cellular abnormalities, including supernumerary centrosomes, multipolar spindles, and defects in cytokinesis. While these observations were made over 15 years ago, identification of the bacterial factors responsible has been elusive due to the genetic intractability of Chlamydia. Recent advances in techniques of genetic manipulation now allows for the direct linking of bacterial virulence factors to manipulation of centrosome duplication and cell cycle progression. In this review, we discuss the impact, both immediate and downstream, of C. trachomatis infection on the host cell cycle regulatory apparatus and centrosome replication. We highlight links between C. trachomatis infection and cervical and ovarian cancers and speculate whether perturbations of the cell cycle and centrosome are sufficient to initiate cellular transformation. We also explore the biological mechanisms employed by Inc proteins and other secreted effector proteins implicated in the perturbation of these host cell pathways. Future work is needed to better understand the nuances of each effector's mechanism and their collective impact on Chlamydia's ability to induce host cellular abnormalities.
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14
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Haines A, Wesolowski J, Paumet F. Chlamydia trachomatis Subverts Alpha-Actinins To Stabilize Its Inclusion. Microbiol Spectr 2023; 11:e0261422. [PMID: 36651786 PMCID: PMC9927245 DOI: 10.1128/spectrum.02614-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of sexually transmitted bacterial disease and a global health burden. As an obligate intracellular pathogen, Chlamydia has evolved many strategies to manipulate its host and establish its intracellular niche called the inclusion. C. trachomatis reorganizes the host actin cytoskeleton to form scaffolds around the inclusion and reinforce the growing inclusion membrane. To control the kinetics and formation of actin scaffolds, Chlamydia expresses the effector InaC/CT813, which activates the host GTPase RhoA. Here, we have discovered that InaC stabilizes actin scaffolds through the host actin cross-linking proteins α-actinins 1 and 4. We demonstrate that α-actinins are recruited to the inclusion membrane in an InaC-dependent manner and associate with actin scaffolds that envelop the inclusion. Small interfering RNA (siRNA)-mediated knockdown of α-actinins differentially regulate the frequency of actin scaffolds and impair inclusion stability, leaving them susceptible to rupture and to nonionic detergent extraction. Overall, our data identify new host effectors that are subverted by InaC to stabilize actin scaffolds, highlighting the versatility of InaC as a key regulator of the host cytoskeletal network during Chlamydia infection. IMPORTANCE Despite antibiotics, recurrent C. trachomatis infections cause significant damage to the genital tract in men and women. Without a preventative vaccine, it is paramount to understand the virulence mechanisms that Chlamydia employs to cause disease. In this context, manipulation of the host cytoskeleton is a critical component of Chlamydia development. Actin scaffolds reinforce the integrity of Chlamydia's infectious vacuole, which is a critical barrier between Chlamydia and the host environment. Having previously established that InaC co-opts RhoA to promote the formation of actin scaffolds around the inclusion, we now show that Chlamydia hijacks a new class of host effectors, α-actinins, to cross-link these scaffolds and further stabilize the inclusion. We also establish that a core function of the chlamydial effector InaC is the regulation of cytoskeletal stability during Chlamydia infection. Ultimately, this work expands our understanding of how bacterial pathogens subvert the actin cytoskeleton by targeting fundamental host effector proteins.
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Affiliation(s)
- A. Haines
- Department of Immunology and Microbiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - J. Wesolowski
- Department of Immunology and Microbiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - F. Paumet
- Department of Immunology and Microbiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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15
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Singh J, Sanghavi P, Mallik R. Microtubule motor driven interactions of lipid droplets: Specificities and opportunities. Front Cell Dev Biol 2022; 10:893375. [PMID: 36200039 PMCID: PMC9527339 DOI: 10.3389/fcell.2022.893375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Lipid Droplets (LDs) are evolutionarily conserved cellular organelles that store neutral lipids such as triacylglycerol and cholesterol-esters. Neutral lipids are enclosed within the limiting membrane of the LD, which is a monolayer of phospholipids and is therefore fundamentally different from the bilayer membrane enclosing most other organelles. LDs have long been viewed as a storehouse of lipids needed on demand for generating energy and membranes inside cells. Outside this classical view, we are now realizing that LDs have significant roles in protein sequestration, supply of signalling lipids, viral replication, lipoprotein production and many other functions of important physiological consequence. To execute such functions, LDs must often exchange lipids and proteins with other organelles (e.g., the ER, lysosomes, mitochondria) via physical contacts. But before such exchanges can occur, how does a micron-sized LD with limited ability to diffuse around find its cognate organelle? There is growing evidence that motor protein driven motion of LDs along microtubules may facilitate such LD-organelle interactions. We will summarize some aspects of LD motion leading to LD-organelle contacts, how these change with metabolic state and pathogen infections, and also ask how these pathways could perhaps be targeted selectively in the context of disease and drug delivery. Such a possibility arises because the binding of motor proteins to the monolayer membrane on LDs could be different from motor binding to the membrane on other cellular organelles.
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Affiliation(s)
- Jagjeet Singh
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
- *Correspondence: Roop Mallik, ; Jagjeet Singh,
| | - Paulomi Sanghavi
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Roop Mallik
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- *Correspondence: Roop Mallik, ; Jagjeet Singh,
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16
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Ölander M, Sixt BS. Bringing genetics to heretofore intractable obligate intracellular bacterial pathogens: Chlamydia and beyond. PLoS Pathog 2022; 18:e1010669. [PMID: 35901011 PMCID: PMC9333220 DOI: 10.1371/journal.ppat.1010669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Magnus Ölander
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Barbara S. Sixt
- Department of Molecular Biology, Umeå University, Umeå, Sweden
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
- * E-mail:
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17
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Cross Talk between ARF1 and RhoA Coordinates the Formation of Cytoskeletal Scaffolds during Chlamydia Infection. mBio 2021; 12:e0239721. [PMID: 34903051 PMCID: PMC8669492 DOI: 10.1128/mbio.02397-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chlamydia trachomatis is an obligate intracellular bacterium that has developed sophisticated mechanisms to survive inside its infectious compartment, the inclusion. Notably, Chlamydia weaves an extensive network of microtubules (MTs) and actin filaments to enable interactions with host organelles and enhance its stability. Despite the global health and economic burden caused by this sexually transmitted pathogen, little is known about how actin and MT scaffolds are integrated into an increasingly complex virulence system. Previously, we established that the chlamydial effector InaC interacts with ARF1 to stabilize MTs. We now demonstrate that InaC regulates RhoA to control actin scaffolds. InaC relies on cross talk between ARF1 and RhoA to coordinate MTs and actin, where the presence of RhoA downregulates stable MT scaffolds and ARF1 activation inhibits actin scaffolds. Understanding how Chlamydia hijacks complex networks will help elucidate how this clinically significant pathogen parasitizes its host and reveal novel cellular signaling pathways.
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Pavišić V, Mahmutefendić Lučin H, Blagojević Zagorac G, Lučin P. Arf GTPases Are Required for the Establishment of the Pre-Assembly Compartment in the Early Phase of Cytomegalovirus Infection. Life (Basel) 2021; 11:867. [PMID: 34440611 PMCID: PMC8399710 DOI: 10.3390/life11080867] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/31/2022] Open
Abstract
Shortly after entering the cells, cytomegaloviruses (CMVs) initiate massive reorganization of cellular endocytic and secretory pathways, which results in the forming of the cytoplasmic virion assembly compartment (AC). We have previously shown that the formation of AC in murine CMV- (MCMV) infected cells begins in the early phase of infection (at 4-6 hpi) with the pre-AC establishment. Pre-AC comprises membranes derived from the endosomal recycling compartment, early endosomes, and the trans-Golgi network, which is surrounded by fragmented Golgi cisterns. To explore the importance of Arf GTPases in the biogenesis of the pre-AC, we infected Balb 3T3 cells with MCMV and analyzed the expression and intracellular localization of Arf proteins in the early phases (up to 16 hpi) of infection and the development of pre-AC in cells with a knockdown of Arf protein expression by small interfering RNAs (siRNAs). Herein, we show that even in the early phase, MCMVs cause massive reorganization of the Arf system of the host cells and induce the over-recruitment of Arf proteins onto the membranes of pre-AC. Knockdown of Arf1, Arf3, Arf4, or Arf6 impaired the establishment of pre-AC. However, the knockdown of Arf1 and Arf6 also abolished the establishment of infection. Our study demonstrates that Arf GTPases are required for different steps of early cytomegalovirus infection, including the establishment of the pre-AC.
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Affiliation(s)
- Valentino Pavišić
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
| | - Hana Mahmutefendić Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Gordana Blagojević Zagorac
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
| | - Pero Lučin
- Department of Physiology and Immunology, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia; (V.P.); (H.M.L.); (P.L.)
- Nursing Department, University North, University Center Varaždin, Jurja Križanića 31b, 42000 Varaždin, Croatia
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19
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Persistence Alters the Interaction between Chlamydia trachomatis and Its Host Cell. Infect Immun 2021; 89:e0068520. [PMID: 34001559 DOI: 10.1128/iai.00685-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In response to stress, the obligate intracellular pathogen Chlamydia trachomatis stops dividing and halts its biphasic developmental cycle. The infectious, extracellular form of this bacterium is highly susceptible to killing by the host immune response, and by pausing development, Chlamydia can survive in an intracellular, "aberrant" state for extended periods of time. The relevance of these aberrant forms has long been debated, and many questions remain concerning how they contribute to the persistence and pathogenesis of the organism. Using reporter cell lines, fluorescence microscopy, and a dipeptide labeling strategy, we measured the ability of C. trachomatis to synthesize, assemble, and degrade peptidoglycan under various aberrance-inducing conditions. We found that all aberrance-inducing conditions affect chlamydial peptidoglycan and that some actually halt the biosynthesis pathway early enough to prevent the release of an immunostimulatory peptidoglycan component, muramyl tripeptide. In addition, utilizing immunofluorescence and electron microscopy, we determined that the induction of aberrance can detrimentally affect the development of the microbe's pathogenic vacuole (the inclusion). Taken together, our data indicate that aberrant forms of Chlamydia generated by different environmental stressors can be sorted into two broad categories based on their ability to continue releasing peptidoglycan-derived, immunostimulatory muropeptides and their ability to secrete effector proteins that are normally expressed at the mid- and late stages of the microbe's developmental cycle. Our findings reveal a novel, immunoevasive feature inherent to a subset of aberrant chlamydial forms and provide clarity and context to the numerous persistence mechanisms employed by these ancient, genetically reduced microbes.
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20
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Inclusion Membrane Growth and Composition Are Altered by Overexpression of Specific Inclusion Membrane Proteins in Chlamydia trachomatis L2. Infect Immun 2021; 89:e0009421. [PMID: 33875478 PMCID: PMC8208519 DOI: 10.1128/iai.00094-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of bacterial sexually transmitted infections. This obligate intracellular bacterium develops within a membrane-bound vacuole called an inclusion, which sequesters the chlamydiae from the host cytoplasm. Host-pathogen interactions at this interface are mediated by chlamydial inclusion membrane proteins (Incs). However, the specific functions of most Incs are poorly characterized. Previous work from our laboratories indicated that expressing an IncF fusion protein at high levels in C. trachomatis L2 negatively impacted inclusion expansion and progeny production. We hypothesize that some Incs function in the structure and organization of the inclusion membrane and that overexpression of those Incs will alter the composition of endogenous Incs within the inclusion membrane. Consequently, inclusion biogenesis and chlamydial development are negatively impacted. To investigate this, C. trachomatis L2 was transformed with inducible expression plasmids encoding IncF-, CT813-, or CT226-FLAG. Overexpression of IncF-FLAG or CT813-FLAG, but not CT226-FLAG, altered chlamydial development, as demonstrated by smaller inclusions, fewer progeny, and increased plasmid loss. The overexpression of CT813-FLAG reduced the detectable levels of endogenous IncE and IncG in the inclusion membrane. Notably, recruitment of sorting nexin-6, a eukaryotic protein binding partner of IncE, was also reduced after CT813 overexpression. Gene expression studies and ultrastructural analysis of chlamydial organisms demonstrated that chlamydial development was altered when CT813-FLAG was overexpressed. Overall, these data indicate that disrupting the expression of specific Incs changed the composition of Incs within the inclusion membrane and the recruitment of associated host cell proteins, which negatively impacted C. trachomatis development.
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21
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Dolat L, Valdivia RH. An endometrial organoid model of interactions between Chlamydia and epithelial and immune cells. J Cell Sci 2021; 134:jcs.252403. [PMID: 33468625 DOI: 10.1242/jcs.252403] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Our understanding of how the obligate intracellular bacterial pathogen Chlamydia trachomatis reprograms the function of infected cells in the upper genital tract is largely based on observations made in cell culture with transformed epithelial cell lines. Here, we describe a primary organoid system derived from endometrial tissue to recapitulate epithelial cell diversity, polarity and ensuing responses to Chlamydia infection. Using high-resolution and time-lapse microscopy, we catalog the infection process in organoids from invasion to egress, including the reorganization of the cytoskeleton and positioning of intracellular organelles. We show this model is amenable to screening C. trachomatis mutants for defects in the fusion of pathogenic vacuoles, the recruitment of intracellular organelles and inhibition of cell death. Moreover, we reconstructed a primary immune cell response by co-culturing infected organoids with neutrophils, and determined that effectors like CPAF (also known as CT858) and TepP (also known as CT875) limit the recruitment of neutrophils to infected organoids. Collectively, our model can be applied to study the cell biology of Chlamydia infections in three-dimensional structures that better reflect the diversity of cell types and polarity encountered by Chlamydia in their animal hosts.
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Affiliation(s)
- Lee Dolat
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27701, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27701, USA
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22
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Andersen SE, Bulman LM, Steiert B, Faris R, Weber MM. Got mutants? How advances in chlamydial genetics have furthered the study of effector proteins. Pathog Dis 2021; 79:ftaa078. [PMID: 33512479 PMCID: PMC7862739 DOI: 10.1093/femspd/ftaa078] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 12/17/2020] [Indexed: 02/07/2023] Open
Abstract
Chlamydia trachomatis is the leading cause of infectious blindness and a sexually transmitted infection. All chlamydiae are obligate intracellular bacteria that replicate within a membrane-bound vacuole termed the inclusion. From the confines of the inclusion, the bacteria must interact with many host organelles to acquire key nutrients necessary for replication, all while promoting host cell viability and subverting host defense mechanisms. To achieve these feats, C. trachomatis delivers an arsenal of virulence factors into the eukaryotic cell via a type 3 secretion system (T3SS) that facilitates invasion, manipulation of host vesicular trafficking, subversion of host defense mechanisms and promotes bacteria egress at the conclusion of the developmental cycle. A subset of these proteins intercalate into the inclusion and are thus referred to as inclusion membrane proteins. Whereas others, referred to as conventional T3SS effectors, are released into the host cell where they localize to various eukaryotic organelles or remain in the cytosol. Here, we discuss the functions of T3SS effector proteins with a focus on how advances in chlamydial genetics have facilitated the identification and molecular characterization of these important factors.
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Affiliation(s)
- Shelby E Andersen
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lanci M Bulman
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Brianna Steiert
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mary M Weber
- Department of Microbiology and Immunology, University of Iowa Carver College of Medicine, Iowa City, IA 52242, USA
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23
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Eukaryotic SNARE VAMP3 Dynamically Interacts with Multiple Chlamydial Inclusion Membrane Proteins. Infect Immun 2021; 89:IAI.00409-20. [PMID: 33229367 PMCID: PMC7822134 DOI: 10.1128/iai.00409-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/15/2020] [Indexed: 01/13/2023] Open
Abstract
Chlamydia trachomatis, an obligate intracellular pathogen, undergoes a biphasic developmental cycle within a membrane-bound vacuole called the chlamydial inclusion. To facilitate interactions with the host cell, Chlamydia modifies the inclusion membrane with type III secreted proteins, called Incs. Chlamydia trachomatis, an obligate intracellular pathogen, undergoes a biphasic developmental cycle within a membrane-bound vacuole called the chlamydial inclusion. To facilitate interactions with the host cell, Chlamydia modifies the inclusion membrane with type III secreted proteins, called Incs. As with all chlamydial proteins, Incs are temporally expressed, modifying the chlamydial inclusion during the early and mid-developmental cycle. VAMP3 and VAMP4 are eukaryotic SNARE proteins that mediate membrane fusion and are recruited to the inclusion to facilitate inclusion expansion. Their recruitment requires de novo chlamydial protein synthesis during the mid-developmental cycle. Thus, we hypothesize that VAMP3 and VAMP4 are recruited by Incs. In chlamydia-infected cells, identifying Inc binding partners for SNARE proteins specifically has been elusive. To date, most studies examining chlamydial Inc and eukaryotic proteins have benefitted from stable interacting partners or a robust interaction at a specific time postinfection. While these types of interactions are the predominant class that have been identified, they are likely the exception to chlamydia-host interactions. Therefore, we applied two separate but complementary experimental systems to identify candidate chlamydial Inc binding partners for VAMPs. Based on these results, we created transformed strains of C. trachomatis serovar L2 to inducibly express a candidate Inc-FLAG protein. In chlamydia-infected cells, we found that five Incs temporally and transiently interact with VAMP3. Further, loss of incA or ct813 expression altered VAMP3 localization to the inclusion. For the first time, our studies demonstrate the transient nature of certain host protein-Inc interactions that contribute to the chlamydial developmental cycle.
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24
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Host and Bacterial Glycolysis during Chlamydia trachomatis Infection. Infect Immun 2020; 88:IAI.00545-20. [PMID: 32900818 DOI: 10.1128/iai.00545-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 09/02/2020] [Indexed: 12/14/2022] Open
Abstract
The obligate intracellular pathogen Chlamydia trachomatis is the leading cause of noncongenital blindness and causative agent of the most common sexually transmitted infection of bacterial origin. With a reduced genome, C. trachomatis is dependent on its host for survival, in part due to a need for the host cell to compensate for incomplete bacterial metabolic pathways. However, relatively little is known regarding how C. trachomatis is able to hijack host cell metabolism. In this study, we show that two host glycolytic enzymes, aldolase A and pyruvate kinase, as well as lactate dehydrogenase, are enriched at the C. trachomatis inclusion membrane during infection. Inclusion localization was not species specific, since a similar phenotype was observed with C. muridarum Time course experiments showed that the number of positive inclusions increased throughout the developmental cycle. In addition, these host enzymes colocalized to the same inclusion, and their localization did not appear to be dependent on sustained bacterial protein synthesis or on intact host actin, vesicular trafficking, or microtubules. Depletion of the host glycolytic enzyme aldolase A resulted in decreased inclusion size and infectious progeny production, indicating a role for host glycolysis in bacterial growth. Finally, quantitative PCR analysis showed that expression of C. trachomatis glycolytic enzymes inversely correlated with host enzyme localization at the inclusion. We discuss potential mechanisms leading to inclusion localization of host glycolytic enzymes and how it could benefit the bacteria. Altogether, our findings provide further insight into the intricate relationship between host and bacterial metabolism during Chlamydia infection.
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Proximity Labeling To Map Host-Pathogen Interactions at the Membrane of a Bacterium-Containing Vacuole in Chlamydia trachomatis-Infected Human Cells. Infect Immun 2019; 87:IAI.00537-19. [PMID: 31405957 PMCID: PMC6803327 DOI: 10.1128/iai.00537-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 08/06/2019] [Indexed: 02/06/2023] Open
Abstract
Many intracellular bacteria, including the obligate intracellular pathogen Chlamydia trachomatis, grow within a membrane-bound bacterium-containing vacuole (BCV). Secreted cytosolic effectors modulate host activity, but an understanding of the host-pathogen interactions that occur at the BCV membrane is limited by the difficulty in purifying membrane fractions from infected host cells. Many intracellular bacteria, including the obligate intracellular pathogen Chlamydia trachomatis, grow within a membrane-bound bacterium-containing vacuole (BCV). Secreted cytosolic effectors modulate host activity, but an understanding of the host-pathogen interactions that occur at the BCV membrane is limited by the difficulty in purifying membrane fractions from infected host cells. We used the ascorbate peroxidase (APEX2) proximity labeling system, which labels proximal proteins with biotin in vivo, to study the protein-protein interactions that occur at the chlamydial vacuolar, or inclusion, membrane. An in vivo understanding of the secreted chlamydial inclusion membrane protein (Inc) interactions (e.g., Inc-Inc and Inc-eukaryotic protein) and how these contribute to overall host-chlamydia interactions at this unique membrane is lacking. We hypothesize some Incs organize the inclusion membrane, whereas other Incs bind eukaryotic proteins to promote chlamydia-host interactions. To study this, Incs fused to APEX2 were expressed in C. trachomatis L2. Affinity purification-mass spectrometry (AP-MS) identified biotinylated proteins, which were analyzed for statistical significance using significance analysis of the interactome (SAINT). Broadly supporting both Inc-Inc and Inc-host interactions, our Inc-APEX2 constructs labeled Incs as well as known and previously unreported eukaryotic proteins localizing to the inclusion. We demonstrate, using bacterial two-hybrid and coimmunoprecipitation assays, that endogenous LRRFIP1 (LRRF1) is recruited to the inclusion by the Inc CT226. We further demonstrate interactions between CT226 and the Incs used in our study to reveal a model for inclusion membrane organization. Combined, our data highlight the utility of APEX2 to capture the complex in vivo protein-protein interactions at the chlamydial inclusion.
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26
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Gitsels A, Sanders N, Vanrompay D. Chlamydial Infection From Outside to Inside. Front Microbiol 2019; 10:2329. [PMID: 31649655 PMCID: PMC6795091 DOI: 10.3389/fmicb.2019.02329] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 09/24/2019] [Indexed: 12/16/2022] Open
Abstract
Chlamydia are obligate intracellular bacteria, characterized by a unique biphasic developmental cycle. Specific interactions with the host cell are crucial for the bacteria’s survival and amplification because of the reduced chlamydial genome. At the start of infection, pathogen-host interactions are set in place in order for Chlamydia to enter the host cell and reach the nutrient-rich peri-Golgi region. Once intracellular localization is established, interactions with organelles and pathways of the host cell enable the necessary hijacking of host-derived nutrients. Detailed information on the aforementioned processes will increase our understanding on the intracellular pathogenesis of chlamydiae and hence might lead to new strategies to battle chlamydial infection. This review summarizes how chlamydiae generate their intracellular niche in the host cell, acquire host-derived nutrients in order to enable their growth and finally exit the host cell in order to infect new cells. Moreover, the evolution in the development of molecular genetic tools, necessary for studying the chlamydial infection biology in more depth, is discussed in great detail.
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Affiliation(s)
- Arlieke Gitsels
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory for Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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27
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Mehta AP, Ko Y, Supekova L, Pestonjamasp K, Li J, Schultz PG. Toward a Synthetic Yeast Endosymbiont with a Minimal Genome. J Am Chem Soc 2019; 141:13799-13802. [PMID: 31419116 DOI: 10.1021/jacs.9b08290] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Based on the endosymbiotic theory, one of the key events that occurred during mitochondrial evolution was an extensive loss of nonessential genes from the protomitochondrial endosymbiont genome and transfer of some of the essential endosymbiont genes to the host nucleus. We have developed an approach to recapitulate various aspects of endosymbiont genome minimization using a synthetic system consisting of Escherichia coli endosymbionts within host yeast cells. As a first step, we identified a number of E. coli auxotrophs of central metabolites that can form viable endosymbionts within yeast cells. These studies provide a platform to identify nonessential biosynthetic pathways that can be deleted in the E. coli endosymbionts to investigate the evolutionary adaptations in the host and endosymbiont during the evolution of mitochondria.
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Affiliation(s)
- Angad P Mehta
- The Department of Chemistry , Scripps Research , La Jolla , California 92037 , United States
| | - Yeonjin Ko
- The Department of Chemistry , Scripps Research , La Jolla , California 92037 , United States
| | - Lubica Supekova
- The Department of Chemistry , Scripps Research , La Jolla , California 92037 , United States
| | - Kersi Pestonjamasp
- The Core Microscopy Facility , Scripps Research , La Jolla , California 92037 , United States
| | - Jack Li
- The Department of Chemistry , Scripps Research , La Jolla , California 92037 , United States
| | - Peter G Schultz
- The Department of Chemistry , Scripps Research , La Jolla , California 92037 , United States
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Bugalhão JN, Mota LJ. The multiple functions of the numerous Chlamydia trachomatis secreted proteins: the tip of the iceberg. MICROBIAL CELL 2019; 6:414-449. [PMID: 31528632 PMCID: PMC6717882 DOI: 10.15698/mic2019.09.691] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Chlamydia trachomatis serovars are obligate intracellular bacterial pathogens mainly causing ocular and urogenital infections that affect millions of people worldwide and which can lead to blindness or sterility. They reside and multiply intracellularly within a membrane-bound vacuolar compartment, known as inclusion, and are characterized by a developmental cycle involving two morphologically and physiologically distinct chlamydial forms. Completion of the developmental cycle involves the secretion of > 70 C. trachomatis proteins that function in the host cell cytoplasm and nucleus, in the inclusion membrane and lumen, and in the extracellular milieu. These proteins can, for example, interfere with the host cell cytoskeleton, vesicular and non-vesicular transport, metabolism, and immune signalling. Generally, this promotes C. trachomatis invasion into, and escape from, host cells, the acquisition of nutrients by the chlamydiae, and evasion of cell-autonomous, humoral and cellular innate immunity. Here, we present an in-depth review on the current knowledge and outstanding questions about these C. trachomatis secreted proteins.
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Affiliation(s)
- Joana N Bugalhão
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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Dolat L, Valdivia RH. A renewed tool kit to explore Chlamydia pathogenesis: from molecular genetics to new infection models. F1000Res 2019; 8. [PMID: 31249676 PMCID: PMC6589931 DOI: 10.12688/f1000research.18832.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/12/2019] [Indexed: 12/21/2022] Open
Abstract
Chlamydia trachomatis is the most prevalent sexually transmitted bacterial pathogen and the leading cause of preventable blindness in the developing world.
C. trachomatis invades the epithelium of the conjunctiva and genital tract and replicates within an intracellular membrane-bound compartment termed the inclusion. To invade and replicate in mammalian cells,
Chlamydia remodels epithelial surfaces by reorganizing the cytoskeleton and cell–cell adhesions, reprograms membrane trafficking, and modulates cell signaling to dampen innate immune responses. If the infection ascends to the upper female genital tract, it can result in pelvic inflammatory disease and tissue scarring.
C. trachomatis infections are associated with infertility, ectopic pregnancies, the fibrotic disorder endometriosis, and potentially cancers of the cervix and uterus. Unfortunately, the molecular mechanisms by which this clinically important human pathogen subverts host cellular functions and causes disease have remained relatively poorly understood because of the dearth of molecular genetic tools to study
Chlamydiae and limitations of both
in vivo and
in vitro infection models. In this review, we discuss recent advances in the experimental molecular tool kit available to dissect
C. trachomatis infections with a special focus on
Chlamydia-induced epithelial barrier disruption by regulating the structure, function, and dynamics of epithelial cell–cell junctions.
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Affiliation(s)
- Lee Dolat
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, USA
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Cortina ME, Ende RJ, Bishop RC, Bayne C, Derré I. Chlamydia trachomatis and Chlamydia muridarum spectinomycin resistant vectors and a transcriptional fluorescent reporter to monitor conversion from replicative to infectious bacteria. PLoS One 2019; 14:e0217753. [PMID: 31170215 PMCID: PMC6553856 DOI: 10.1371/journal.pone.0217753] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 05/17/2019] [Indexed: 12/17/2022] Open
Abstract
Chlamydia trachomatis infections are the leading cause of sexually transmitted infections of bacterial origin. Lower genital tract infections are often asymptomatic, and therefore left untreated, leading to ascending infections that have long-term consequences on female reproductive health. Human pathology can be recapitulated in mice with the mouse adapted strain C. muridarum. Eight years into the post-genetic era, significant advances to expand the Chlamydia genetic toolbox have been made to facilitate the study of this important human pathogen. However, the need for additional tools remains, especially for C. muridarum. Here, we describe a new set of spectinomycin resistant E. coli-Chlamydia shuttle vectors, for C. trachomatis and C. muridarum. These versatile vectors allow for expression and localization studies of Chlamydia effectors, such as Inc proteins, and will be instrumental for mutant complementation studies. In addition, we have exploited the differential expression of specific Chlamydia genes during the developmental cycle to engineer an omcA::gfp fluorescent transcriptional reporter. This novel tool allows for monitoring RB to EB conversion at the bacterial level. Spatiotemporal tracking of GFP expression within individual inclusions revealed that RB to EB conversion initiates in bacteria located at the edge of the inclusion and correlates with the time post initiation of bacterial replication and inclusion size. Comparison between primary and secondary inclusions potentially suggests that the environment in which the inclusions develop influences the timing of conversion. Altogether, the Chlamydia genetic tools described here will benefit the field, as we continue to investigate the molecular mechanisms underlying Chlamydia-host interaction and pathogenesis.
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Affiliation(s)
- María Eugenia Cortina
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Rachel J. Ende
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - R. Clayton Bishop
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Charlie Bayne
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Isabelle Derré
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
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Pais SV, Key CE, Borges V, Pereira IS, Gomes JP, Fisher DJ, Mota LJ. CteG is a Chlamydia trachomatis effector protein that associates with the Golgi complex of infected host cells. Sci Rep 2019; 9:6133. [PMID: 30992493 PMCID: PMC6468002 DOI: 10.1038/s41598-019-42647-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/22/2019] [Indexed: 12/17/2022] Open
Abstract
Chlamydia trachomatis is a bacterial pathogen causing ocular and genital infections in humans. C. trachomatis multiplies exclusively inside host cells within a characteristic vacuole, from where it manipulates host cells by injecting them with type III secretion effector proteins. Here, we identified CteG as the first C. trachomatiseffector associated with the Golgi. For this, C. trachomatis strains expressing candidate effectors fused to a double hemagglutinin (2HA) tag were constructed. Then, among these strains, immunofluorescence microscopy revealed that CteG-2HA was delivered into the cytoplasm of infected cells. Between 16–20 h post-infection, CteG-2HA mostly associated with the Golgi; however, CteG-2HA also appeared at the host cell plasma membrane, and at 30 or 40 h post-infection this was its predominant localization. This change in the main localization of CteG-2HA was independent of intact microfilaments or microtubules. Ectopic expression of different regions of CteG (656 amino acid residues) in uninfected cells revealed that its first 100 residues contain a Golgi targeting region. Although a C. trachomatis cteG mutant did not display a defect in intracellular multiplication, CteG induced a vacuolar protein sorting defect when expressed in Saccharomyces cerevisiae. This suggested that CteG might function by subverting host cell vesicular transport.
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Affiliation(s)
- Sara V Pais
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Charlotte E Key
- Department of Microbiology, Southern Illinois University, Carbondale, Illinois, USA
| | - Vítor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Inês S Pereira
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Derek J Fisher
- Department of Microbiology, Southern Illinois University, Carbondale, Illinois, USA
| | - Luís Jaime Mota
- UCIBIO, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal.
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Make It a Sweet Home: Responses of Chlamydia trachomatis to the Challenges of an Intravacuolar Lifestyle. Microbiol Spectr 2019; 7. [PMID: 30848236 DOI: 10.1128/microbiolspec.bai-0005-2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Intravacuolar development has been adopted by several bacteria that grow inside a host cell. Remaining in a vacuole, as opposed to breaching the cytosol, protects the bacteria from some aspects of the cytosolic innate host defense and allows them to build an environment perfectly adapted to their needs. However, this raises new challenges: the host resources are separated from the bacteria by a lipid bilayer that is nonpermeable to most nutrients. In addition, the area of this lipid bilayer needs to expand to accommodate bacterial multiplication. This requires building material and energy that are not directly invested in bacterial growth. This article describes the strategies acquired by the obligate intracellular pathogen Chlamydia trachomatis to circumvent the difficulties raised by an intravacuolar lifestyle. We start with an overview of the origin and composition of the vacuolar membrane. Acquisition of host resources is largely, although not exclusively, mediated by interactions with membranous compartments of the eukaryotic cell, and we describe how the inclusion modifies the architecture of the cell and distribution of the neighboring compartments. The second part of this review describes the four mechanisms characterized so far by which the bacteria acquire resources from the host: (i) transport/diffusion across the vacuole membrane, (ii) fusion of this membrane with host compartments, (iii) direct transfer of lipids at membrane contact sites, and (iv) engulfment by the vacuole membrane of large cytoplasmic entities.
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George Z, Omosun Y, Azenabor AA, Goldstein J, Partin J, Joseph K, Ellerson D, He Q, Eko F, McDonald MA, Reed M, Svoboda P, Stuchlik O, Pohl J, Lutter E, Bandea C, Black CM, Igietseme JU. The molecular mechanism of induction of unfolded protein response by Chlamydia. Biochem Biophys Res Commun 2019; 508:421-429. [PMID: 30503337 PMCID: PMC6343654 DOI: 10.1016/j.bbrc.2018.11.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 11/06/2018] [Indexed: 11/21/2022]
Abstract
The unfolded protein response (UPR) contributes to chlamydial pathogenesis, as a source of lipids and ATP during replication, and for establishing the initial anti-apoptotic state of host cell that ensures successful inclusion development. The molecular mechanism(s) of UPR induction by Chlamydia is unknown. Chlamydia use type III secretion system (T3SS) effector proteins (e.g, the Translocated Actin-Recruiting Phosphoprotein (Tarp) to stimulate host cell's cytoskeletal reorganization that facilitates invasion and inclusion development. We investigated the hypothesis that T3SS effector-mediated assembly of myosin-II complex produces activated non-muscle myosin heavy chain II (NMMHC-II), which then binds the UPR master regulator (BiP) and/or transducers to induce UPR. Our results revealed the interaction of the chlamydial effector proteins (CT228 and Tarp) with components of the myosin II complex and UPR regulator and transducer during infection. These interactions caused the activation and binding of NMMHC-II to BiP and IRE1α leading to UPR induction. In addition, specific inhibitors of myosin light chain kinase, Tarp oligomerization and myosin ATPase significantly reduced UPR activation and Chlamydia replication. Thus, Chlamydia induce UPR through T3SS effector-mediated activation of NMMHC-II components of the myosin complex to facilitate infectivity. The finding provides greater insights into chlamydial pathogenesis with the potential to identify therapeutic targets and formulations.
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Affiliation(s)
- Zenas George
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Yusuf Omosun
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA; Morehouse School of Medicine, Atlanta, GA, USA
| | | | - Jason Goldstein
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - James Partin
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Kahaliah Joseph
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Debra Ellerson
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Qing He
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA; Morehouse School of Medicine, Atlanta, GA, USA
| | - Francis Eko
- Morehouse School of Medicine, Atlanta, GA, USA
| | | | - Matthew Reed
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Pavel Svoboda
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Olga Stuchlik
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Jan Pohl
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | | | - Claudiu Bandea
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Carolyn M Black
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Joseph U Igietseme
- Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA; Morehouse School of Medicine, Atlanta, GA, USA.
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Martinez E, Siadous FA, Bonazzi M. Tiny architects: biogenesis of intracellular replicative niches by bacterial pathogens. FEMS Microbiol Rev 2018; 42:425-447. [PMID: 29596635 DOI: 10.1093/femsre/fuy013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 03/26/2018] [Indexed: 11/13/2022] Open
Abstract
Co-evolution of bacterial pathogens with their hosts led to the emergence of a stunning variety of strategies aiming at the evasion of host defences, colonisation of host cells and tissues and, ultimately, the establishment of a successful infection. Pathogenic bacteria are typically classified as extracellular and intracellular; however, intracellular lifestyle comes in many different flavours: some microbes rapidly escape to the cytosol whereas other microbes remain within vacuolar compartments and harness membrane trafficking pathways to generate their host-derived, pathogen-specific replicative niche. Here we review the current knowledge on a variety of vacuolar lifestyles, the effector proteins used by bacteria as tools to take control of the host cell and the main membrane trafficking signalling pathways targeted by vacuolar pathogens as source of membranes and nutrients. Finally, we will also discuss how host cells have developed countermeasures to sense the biogenesis of the aberrant organelles harbouring bacteria. Understanding the dialogue between bacterial and eukaryotic proteins is the key to unravel the molecular mechanisms of infection and in turn, this may lead to the identification of new targets for the development of new antimicrobials.
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Affiliation(s)
- Eric Martinez
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
| | | | - Matteo Bonazzi
- IRIM, University of Montpellier, CNRS, 34293 Montpellier, France
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35
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Shaw JH, Key CE, Snider TA, Sah P, Shaw EI, Fisher DJ, Lutter EI. Genetic Inactivation of Chlamydia trachomatis Inclusion Membrane Protein CT228 Alters MYPT1 Recruitment, Extrusion Production, and Longevity of Infection. Front Cell Infect Microbiol 2018; 8:415. [PMID: 30555802 PMCID: PMC6284022 DOI: 10.3389/fcimb.2018.00415] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/08/2018] [Indexed: 02/01/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular pathogen with global health and economic impact. Upon infection, C. trachomatis resides within a protective niche, the inclusion, wherein it replicates and usurps host cell machinery and resources. The inclusion membrane is the key host-pathogen interface that governs specific protein-protein interactions to manipulate host signaling pathways. At the conclusion of the infection cycle, C. trachomatis exits the host cell via lysis or extrusion. Extrusion depends on the phosphorylation state of myosin light chain 2 (MLC2); the extent of phosphorylation is determined by the ongoing opposing activities of myosin phosphatase (MYPT1) and myosin kinase (MLCK). Previously, it was shown that MYPT1 is recruited to the inclusion and interacts with CT228 for regulation of host cell egress. In this study, we generated a targeted chromosomal mutation of CT228 (L2-ΔCT228) using the TargeTron system and demonstrate a loss of MYPT1 recruitment and increase in extrusion production in vitro. Mutation of CT228 did not affect chlamydial growth in cell culture or recruitment of MLC2. Moreover, we document a delay in clearance of L2-ΔCT228 during murine intravaginal infection as well as a reduction in systemic humoral response, relative to L2-wild type. Taken together, the data suggest that loss of MYPT1 recruitment (as a result of CT228 disruption) regulates the degree of host cell exit via extrusion and affects the longevity of infection in vivo.
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Affiliation(s)
- Jennifer H. Shaw
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States,*Correspondence: Jennifer H. Shaw
| | - Charlotte E. Key
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, United States
| | - Timothy A. Snider
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK, United States
| | - Prakash Sah
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Edward I. Shaw
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States
| | - Derek J. Fisher
- Department of Microbiology, Southern Illinois University, Carbondale, IL, United States
| | - Erika I. Lutter
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, United States,Erika I. Lutter
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Pruneda JN, Bastidas RJ, Bertsoulaki E, Swatek KN, Santhanam B, Clague MJ, Valdivia RH, Urbé S, Komander D. A Chlamydia effector combining deubiquitination and acetylation activities induces Golgi fragmentation. Nat Microbiol 2018; 3:1377-1384. [PMID: 30397340 DOI: 10.1038/s41564-018-0271-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/13/2018] [Indexed: 01/10/2023]
Abstract
Pathogenic bacteria are armed with potent effector proteins that subvert host signalling processes during infection1. The activities of bacterial effectors and their associated roles within the host cell are often poorly understood, particularly for Chlamydia trachomatis2, a World Health Organization designated neglected disease pathogen. We identify and explain remarkable dual Lys63-deubiquitinase (DUB) and Lys-acetyltransferase activities in the Chlamydia effector ChlaDUB1. Crystal structures capturing intermediate stages of each reaction reveal how the same catalytic centre of ChlaDUB1 can facilitate such distinct processes, and enable the generation of mutations that uncouple the two activities. Targeted Chlamydia mutant strains allow us to link the DUB activity of ChlaDUB1 and the related, dedicated DUB ChlaDUB2 to fragmentation of the host Golgi apparatus, a key process in Chlamydia infection for which effectors have remained elusive. Our work illustrates the incredible versatility of bacterial effector proteins, and provides important insights towards understanding Chlamydia pathogenesis.
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Affiliation(s)
- Jonathan N Pruneda
- Division of Protein and Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Robert J Bastidas
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Erithelgi Bertsoulaki
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Kirby N Swatek
- Division of Protein and Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Balaji Santhanam
- Division of Structural Studies, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Michael J Clague
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Raphael H Valdivia
- Department of Molecular Genetics and Microbiology, Duke University, Durham, NC, USA
| | - Sylvie Urbé
- Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - David Komander
- Division of Protein and Nucleic Acid Chemistry, MRC Laboratory of Molecular Biology, Cambridge, UK.
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Engineering yeast endosymbionts as a step toward the evolution of mitochondria. Proc Natl Acad Sci U S A 2018; 115:11796-11801. [PMID: 30373839 DOI: 10.1073/pnas.1813143115] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been hypothesized that mitochondria evolved from a bacterial ancestor that initially became established in an archaeal host cell as an endosymbiont. Here we model this first stage of mitochondrial evolution by engineering endosymbiosis between Escherichia coli and Saccharomyces cerevisiae An ADP/ATP translocase-expressing E. coli provided ATP to a respiration-deficient cox2 yeast mutant and enabled growth of a yeast-E. coli chimera on a nonfermentable carbon source. In a reciprocal fashion, yeast provided thiamin to an endosymbiotic E. coli thiamin auxotroph. Expression of several SNARE-like proteins in E. coli was also required, likely to block lysosomal degradation of intracellular bacteria. This chimeric system was stable for more than 40 doublings, and GFP-expressing E. coli endosymbionts could be observed in the yeast by fluorescence microscopy and X-ray tomography. This readily manipulated system should allow experimental delineation of host-endosymbiont adaptations that occurred during evolution of the current, highly reduced mitochondrial genome.
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38
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Fischer A, Rudel T. Safe haven under constant attack-The Chlamydia-containing vacuole. Cell Microbiol 2018; 20:e12940. [PMID: 30101516 DOI: 10.1111/cmi.12940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 07/24/2018] [Accepted: 07/31/2018] [Indexed: 11/30/2022]
Abstract
Chlamydia belong to the group of obligate intracellular bacteria that reside in a membrane bound vacuole during the entire intracellular phase of their life cycle. This vacuole called inclusion shields the bacteria from adverse influences in the cytosol of the host cell like the destructive machinery of the cell-autonomous defence system. The inclusion thereby prevents the digestion and eradication in specialised compartments of the intact and viable cell called phagolysosomes or autophagolysosomes. It is becoming more and more evident that keeping the inclusion intact also prevents the onset of cell intrinsic cell death programmes that are activated upon damage of the inclusion and direct the cell to destruct itself and the pathogen inside. Chlamydia secrete numerous proteins into the inclusion membrane to protect and stabilise their unique niche inside the host cell. We will focus in this review on the diverse attack strategies of the host aiming at the destruction of the Chlamydia-containing inclusion and will summarise the current knowledge on the protection mechanisms elaborated by the bacteria to maintain the integrity of their replication niche.
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Affiliation(s)
- Annette Fischer
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
| | - Thomas Rudel
- Department of Microbiology, University of Würzburg Biocenter, Würzburg, Germany
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Almeida F, Luís MP, Pereira IS, Pais SV, Mota LJ. The Human Centrosomal Protein CCDC146 Binds Chlamydia trachomatis Inclusion Membrane Protein CT288 and Is Recruited to the Periphery of the Chlamydia-Containing Vacuole. Front Cell Infect Microbiol 2018; 8:254. [PMID: 30094225 PMCID: PMC6070772 DOI: 10.3389/fcimb.2018.00254] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/04/2018] [Indexed: 01/12/2023] Open
Abstract
Chlamydia trachomatis is an obligate intracellular human pathogen causing mainly ocular and genital infections of significant clinical and public health impact. C. trachomatis multiplies intracellularly in a membrane bound vacuole, known as inclusion. Both extracellularly and from within the inclusion, C. trachomatis uses a type III secretion system to deliver several effector proteins into the cytoplasm of host cells. A large proportion of these effectors, the inclusion membrane (Inc) proteins, are exposed to the host cell cytosol but possess a characteristic hydrophobic domain mediating their insertion in the inclusion membrane. By yeast two-hybrid, we found that C. trachomatis Inc CT288 interacts with the human centrosomal protein CCDC146 (coiled-coil domain-containing protein 146). The interaction was also detected by co-immunoprecipitation in mammalian cells either ectopically expressing CCDC146 and CT288 or ectopically expressing CCDC146 and infected by a C. trachomatis strain expressing epitope-tagged and inclusion membrane-localized CT288. In uninfected mammalian cells, ectopically expressed full-length CCDC146 (955 amino acid residues) localized at the centrosome; but in cells infected by wild-type C. trachomatis, its centrosomal localization was less evident and CCDC146 accumulated around the inclusion. Recruitment of CCDC146 to the inclusion periphery did not require intact host Golgi, microtubules or microfilaments, but was dependent on chlamydial protein synthesis. Full-length CCDC146 also accumulated at the periphery of the inclusion in cells infected by a C. trachomatis ct288 mutant; however, a C-terminal fragment of CCDC146 (residues 692–955), which interacts with CT288, showed differences in localization at the periphery of the inclusion in cells infected by wild-type or ct288 mutant C. trachomatis. This suggests a model in which chlamydial proteins other than CT288 recruit CCDC146 to the periphery of the inclusion, where the CT288-CCDC146 interaction might contribute to modulate the function of this host protein.
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Affiliation(s)
- Filipe Almeida
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Maria P Luís
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Inês Serrano Pereira
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Sara V Pais
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal
| | - Luís Jaime Mota
- Research Unit on Applied Molecular Biosciences (UCIBIO) - REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Costa da Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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Gastrin stimulates pancreatic cancer cell directional migration by activating the Gα12/13-RhoA-ROCK signaling pathway. Exp Mol Med 2018; 50:1-14. [PMID: 29717112 PMCID: PMC5938061 DOI: 10.1038/s12276-018-0081-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 02/02/2018] [Accepted: 02/05/2018] [Indexed: 12/24/2022] Open
Abstract
The mechanism by which gastrin promotes pancreatic cancer cell metastasis is unclear. The process of directing polarized cancer cells toward the extracellular matrix is principally required for invasion and distant metastasis; however, whether gastrin can induce this process and its underlying mechanism remain to be elucidated. In this study, we found that gastrin-induced phosphorylation of paxillin at tyrosine 31/118 and RhoA activation as well as promoted the metastasis of PANC-1 cancer cells. Depletion of Gα12 and Gα13 inhibited the phosphorylation of paxillin and downstream activation of GTP-RhoA, blocked the formation and aggregation of focal adhesions and facilitated polarization of actin filaments induced by gastrin. Suppression of RhoA and ROCK also exhibited identical results. Selective inhibition of the CCKBR–Gα12/13–RhoA–ROCK signaling pathway blocked the reoriented localization of the Golgi apparatus at the leading edge of migrated cancer cells. YM022 and Y-27632 significantly suppressed hepatic metastasis of orthotic pancreatic tumors induced by gastrin in vivo. Collectively, we demonstrate that gastrin promotes Golgi reorientation and directional polarization of pancreatic cancer cells by activation of paxillin via the CCKBR–Gα12/13–RhoA–ROCK signal pathway. A hormone found in high levels in pancreatic cancer sufferers helps the disease spread by co-ordinating cellular migration. Pancreatic cancer is one of the most deadly forms of cancer, being highly aggressive and likely to metastasize. Honggang Yu at Renmin Hospital of Wuhan University and scientists across China have demonstrated that gastrin, a hormone expressed at higher levels in patients with pancreatic cancer, helps to co-ordinate directional cell migration and ensure the disease spreads effectively. By activating two key molecules via a specific signalling pathway, gastrin ensures the correct orientation of the Golgi apparatus, a cellular organelle tasked with packaging proteins for transportation. This in turn activates directional migration of the cancer cells. The results explain why gastrin is over-expressed in both tumors and blood in cancer patients, and may inform future therapies.
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Transformation of Chlamydia: current approaches and impact on our understanding of chlamydial infection biology. Microbes Infect 2018; 20:445-450. [PMID: 29409975 DOI: 10.1016/j.micinf.2018.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/04/2018] [Accepted: 01/05/2018] [Indexed: 12/11/2022]
Abstract
The intonation "The king is dead, long live the king" aptly describes the state of Chlamydia research. Genetic-based approaches are rapidly replacing correlative strategies to provide new insights. We describe how current transformation technologies are enhancing progress in understanding Chlamydia infection biology and present key opportunities for further development.
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Weber MM, Faris R. Subversion of the Endocytic and Secretory Pathways by Bacterial Effector Proteins. Front Cell Dev Biol 2018; 6:1. [PMID: 29417046 PMCID: PMC5787570 DOI: 10.3389/fcell.2018.00001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Accepted: 01/09/2018] [Indexed: 12/22/2022] Open
Abstract
Intracellular bacteria have developed numerous strategies to hijack host vesicular trafficking pathways to form their unique replicative niches. To promote intracellular replication, the bacteria must interact with host organelles and modulate host signaling pathways to acquire nutrients and membrane for the growing parasitophorous vacuole all while suppressing activation of the immune response. To facilitate host cell subversion, bacterial pathogens use specialized secretion systems to deliver bacterial virulence factors, termed effectors, into the host cell that mimic, agonize, and/or antagonize the function of host proteins. In this review we will discuss how bacterial effector proteins from Coxiella burnetii, Brucella abortus, Salmonella enterica serovar Typhimurium, Legionella pneumophila, Chlamydia trachomatis, and Orientia tsutsugamushi manipulate the endocytic and secretory pathways. Understanding how bacterial effector proteins manipulate host processes not only gives us keen insight into bacterial pathogenesis, but also enhances our understanding of how eukaryotic membrane trafficking is regulated.
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Affiliation(s)
- Mary M Weber
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
| | - Robert Faris
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA, United States
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Abstract
Both actin and microtubules are major cytoskeletal elements in eukaryotic cells that participate in many cellular processes, including cell division and motility, vesicle and organelle movement, and the maintenance of cell shape. Inside its host cell, the human pathogen Chlamydia trachomatis manipulates the cytoskeleton to promote its survival and enhance its pathogenicity. In particular, Chlamydia induces the drastic rearrangement of both actin and microtubules, which is vital for its entry, inclusion structure and development, and host cell exit. As significant progress in Chlamydia genetics has greatly enhanced our understanding of how this pathogen co-opts the host cytoskeleton, we will discuss the machinery used by Chlamydia to coordinate the reorganization of actin and microtubules.
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Affiliation(s)
- Jordan Wesolowski
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Fabienne Paumet
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
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Murray R, Flora E, Bayne C, Derré I. IncV, a FFAT motif-containing Chlamydia protein, tethers the endoplasmic reticulum to the pathogen-containing vacuole. Proc Natl Acad Sci U S A 2017; 114:12039-12044. [PMID: 29078338 PMCID: PMC5692559 DOI: 10.1073/pnas.1709060114] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Membrane contact sites (MCS) are zones of contact between the membranes of two organelles. At MCS, specific proteins tether the organelles in close proximity and mediate the nonvesicular trafficking of lipids and ions between the two organelles. The endoplasmic reticulum (ER) integral membrane protein VAP is a common component of MCS involved in both tethering and lipid transfer by binding directly to proteins containing a FFAT [two phenylalanines (FF) in an acidic tract (AT)] motif. In addition to maintaining cell homeostasis, MCS formation recently emerged as a mechanism by which intracellular pathogens hijack cellular resources and establish their replication niche. Here, we investigated the mechanism by which the Chlamydia-containing vacuole, termed the inclusion, establishes direct contact with the ER. We show that the Chlamydia protein IncV, which is inserted into the inclusion membrane, displays one canonical and one noncanonical FFAT motif that cooperatively mediated the interaction of IncV with VAP. IncV overexpression was sufficient to bring the ER in close proximity of IncV-containing membranes. Although IncV deletion partially decreased VAP association with the inclusion, it did not suppress the formation of ER-inclusion MCS, suggesting the existence of redundant mechanisms in MCS formation. We propose a model in which IncV acts as one of the primary tethers that contribute to the formation of ER-inclusion MCS. Our results highlight a previously unidentified mechanism of bacterial pathogenesis and support the notion that cooperation of two FFAT motifs may be a common feature of VAP-mediated MCS formation. Chlamydia-host cell interaction therefore constitutes a unique system to decipher the molecular mechanisms underlying MCS formation.
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Affiliation(s)
- Rebecca Murray
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Elizabeth Flora
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Charlie Bayne
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
| | - Isabelle Derré
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908
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Benabdi S, Peurois F, Nawrotek A, Chikireddy J, Cañeque T, Yamori T, Shiina I, Ohashi Y, Dan S, Rodriguez R, Cherfils J, Zeghouf M. Family-wide Analysis of the Inhibition of Arf Guanine Nucleotide Exchange Factors with Small Molecules: Evidence of Unique Inhibitory Profiles. Biochemistry 2017; 56:5125-5133. [PMID: 28858527 DOI: 10.1021/acs.biochem.7b00706] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Arf GTPases and their guanine nucleotide exchange factors (ArfGEFs) are major regulators of membrane traffic and organelle structure in cells. They are associated with a variety of diseases and are thus attractive therapeutic targets for inhibition by small molecules. Several inhibitors of unrelated chemical structures have been discovered, which have shown their potential in dissecting molecular pathways and blocking disease-related functions. However, their specificity across the ArfGEF family has remained elusive. Importantly, inhibitory responses in the context of membranes, which are critical determinants of Arf and ArfGEF cellular functions, have not been investigated. Here, we compare the efficiency and specificity of four structurally distinct ArfGEF inhibitors, Brefeldin A, SecinH3, M-COPA, and NAV-2729, toward six ArfGEFs (human ARNO, EFA6, BIG1, and BRAG2 and Legionella and Rickettsia RalF). Inhibition was assessed by fluorescence kinetics using pure proteins, and its modulation by membranes was determined with lipidated GTPases in the presence of liposomes. Our analysis shows that despite the intra-ArfGEF family resemblance, each inhibitor has a specific inhibitory profile. Notably, M-COPA is a potent pan-ArfGEF inhibitor, and NAV-2729 inhibits all GEFs, the strongest effects being against BRAG2 and Arf1. Furthermore, the presence of the membrane-binding domain in Legionella RalF reveals a strong inhibitory effect of BFA that is not measured on its GEF domain alone. This study demonstrates the value of family-wide assays with incorporation of membranes, and it should enable accurate dissection of Arf pathways by these inhibitors to best guide their use and development as therapeutic agents.
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Affiliation(s)
- Sarah Benabdi
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - François Peurois
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Agata Nawrotek
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Jahnavi Chikireddy
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Tatiana Cañeque
- Institut Curie, PSL Research University , Chemical Cell Biology group, 26 rue d'Ulm, 75248 Paris Cedex 05, France.,CNRS UMR3666 , 75005 Paris, France.,INSERM U1143 , 75005 Paris, France
| | - Takao Yamori
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Isamu Shiina
- Department of Applied Chemistry, Faculty of Science, Tokyo University of Science , Tokyo 162-8601, Japan
| | - Yoshimi Ohashi
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Shingo Dan
- Division of Molecular Pharmacology, Cancer Chemotherapy Center, Japanese Foundation for Cancer Research , Tokyo 135-8550, Japan
| | - Raphaël Rodriguez
- Institut Curie, PSL Research University , Chemical Cell Biology group, 26 rue d'Ulm, 75248 Paris Cedex 05, France.,CNRS UMR3666 , 75005 Paris, France.,INSERM U1143 , 75005 Paris, France
| | - Jacqueline Cherfils
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
| | - Mahel Zeghouf
- Laboratoire de Biologie et Pharmacologie Appliquée CNRS, Ecole Normale Supérieure Paris-Saclay , 61 avenue du président Wilson, 94235 Cachan, France
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Advances and Obstacles in the Genetic Dissection of Chlamydial Virulence. Curr Top Microbiol Immunol 2017; 412:133-158. [PMID: 29090367 DOI: 10.1007/82_2017_76] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Obligate intracellular pathogens in the family Chlamydiaceae infect taxonomically diverse eukaryotes ranging from amoebae to mammals. However, many fundamental aspects of chlamydial cell biology and pathogenesis remain poorly understood. Genetic dissection of chlamydial biology has historically been hampered by a lack of genetic tools. Exploitation of the ability of chlamydia to recombine genomic material by lateral gene transfer (LGT) ushered in a new era in chlamydia research. With methods to map mutations in place, genetic screens were able to assign functions and phenotypes to specific chlamydial genes. Development of an approach for stable transformation of chlamydia also provided a mechanism for gene delivery and platforms for disrupting chromosomal genes. Here, we explore how these and other tools have been used to test hypotheses concerning the functions of known chlamydial virulence factors and discover the functions of completely uncharacterized genes. Refinement and extension of the existing genetic tools to additional Chlamydia spp. will substantially advance understanding of the biology and pathogenesis of this important group of pathogens.
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