1
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Franklin A, Salgueiro VC, Layton AJ, Sullivan R, Mize T, Vázquez-Iniesta L, Benedict ST, Gurcha SS, Anso I, Besra GS, Banzhaf M, Lovering AL, Williams SJ, Guerin ME, Scott NE, Prados-Rosales R, Lowe EC, Moynihan PJ. The mycobacterial glycoside hydrolase LamH enables capsular arabinomannan release and stimulates growth. Nat Commun 2024; 15:5740. [PMID: 38982040 PMCID: PMC11233589 DOI: 10.1038/s41467-024-50051-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 06/26/2024] [Indexed: 07/11/2024] Open
Abstract
Mycobacterial glycolipids are important cell envelope structures that drive host-pathogen interactions. Arguably, the most important are lipoarabinomannan (LAM) and its precursor, lipomannan (LM), which are trafficked from the bacterium to the host via unknown mechanisms. Arabinomannan is thought to be a capsular derivative of these molecules, lacking a lipid anchor. However, the mechanism by which this material is generated has yet to be elucidated. Here, we describe the identification of a glycoside hydrolase family 76 enzyme that we term LamH (Rv0365c in Mycobacterium tuberculosis) which specifically cleaves α-1,6-mannoside linkages within LM and LAM, driving its export to the capsule releasing its phosphatidyl-myo-inositol mannoside lipid anchor. Unexpectedly, we found that the catalytic activity of this enzyme is important for efficient exit from stationary phase cultures, potentially implicating arabinomannan as a signal for growth phase transition. Finally, we demonstrate that LamH is important for M. tuberculosis survival in macrophages.
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Affiliation(s)
- Aaron Franklin
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Vivian C Salgueiro
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | - Rudi Sullivan
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Todd Mize
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Lucía Vázquez-Iniesta
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | | | | | - Itxaso Anso
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology, Molecular Biology Institute of Barcelona, Spanish National Research Council, Barcelona Science Park, c/Baldiri Reixac 10-12, Tower R, 08028, Barcelona, Catalonia, Spain
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham, UK
| | | | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
| | - Marcelo E Guerin
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Catalonia, Spain
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia
| | - Rafael Prados-Rosales
- Department of Preventive Medicine, Public Health and Microbiology, School of Medicine, Universidad Autonoma de Madrid, Madrid, Spain
| | - Elisabeth C Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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2
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Jones BS, Hu DD, Nicholson KR, Cronin RM, Weaver SD, Champion MM, Champion PA. The loss of the PDIM/PGL virulence lipids causes differential secretion of ESX-1 substrates in Mycobacterium marinum. mSphere 2024; 9:e0000524. [PMID: 38661343 PMCID: PMC11237470 DOI: 10.1128/msphere.00005-24] [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: 01/08/2024] [Accepted: 03/21/2024] [Indexed: 04/26/2024] Open
Abstract
The mycobacterial cell envelope is a major virulence determinant in pathogenic mycobacteria. Specific outer lipids play roles in pathogenesis, modulating the immune system and promoting the secretion of virulence factors. ESX-1 (ESAT-6 system-1) is a conserved protein secretion system required for mycobacterial pathogenesis. Previous studies revealed that mycobacterial strains lacking the outer lipid PDIM have impaired ESX-1 function during laboratory growth and infection. The mechanisms underlying changes in ESX-1 function are unknown. We used a proteo-genetic approach to measure phthiocerol dimycocerosate (PDIM)- and phenolic glycolipid (PGL)-dependent protein secretion in M. marinum, a non-tubercular mycobacterial pathogen that causes tuberculosis-like disease in ectothermic animals. Importantly, M. marinum is a well-established model for mycobacterial pathogenesis. Our findings showed that M. marinum strains without PDIM and PGL showed specific, significant reductions in protein secretion compared to the WT and complemented strains. We recently established a hierarchy for the secretion of ESX-1 substrates in four (I-IV) groups. Loss of PDIM differentially impacted secretion of Group III and IV ESX-1 substrates, which are likely the effectors of pathogenesis. Our data suggest that the altered secretion of specific ESX-1 substrates is responsible for the observed ESX-1-related effects in PDIM-deficient strains.IMPORTANCEMycobacterium tuberculosis, the cause of human tuberculosis, killed an estimated 1.3 million people in 2022. Non-tubercular mycobacterial species cause acute and chronic human infections. Understanding how these bacteria cause disease is critical. Lipids in the cell envelope are essential for mycobacteria to interact with the host and promote disease. Strains lacking outer lipids are attenuated for infection, but the reasons are unclear. Our research aims to identify a mechanism for attenuation of mycobacterial strains without the PDIM and PGL outer lipids in M. marinum. These findings will enhance our understanding of the importance of lipids in pathogenesis and how these lipids contribute to other established virulence mechanisms.
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Affiliation(s)
- Bradley S. Jones
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Daniel D. Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Kathleen R. Nicholson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Rachel M. Cronin
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Simon D. Weaver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew M. Champion
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Patricia A. Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
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3
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Martin M, deVisch A, Boudehen YM, Barthe P, Gutierrez C, Turapov O, Aydogan T, Heriaud L, Gracy J, Neyrolles O, Mukamolova GV, Letourneur F, Cohen-Gonsaud M. A Mycobacterium tuberculosis Effector Targets Mitochondrion, Controls Energy Metabolism, and Limits Cytochrome c Exit. Microbiol Spectr 2023; 11:e0106623. [PMID: 37036353 PMCID: PMC10269737 DOI: 10.1128/spectrum.01066-23] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 03/17/2023] [Indexed: 04/11/2023] Open
Abstract
Host metabolism reprogramming is a key feature of Mycobacterium tuberculosis (Mtb) infection that enables the survival of this pathogen within phagocytic cells and modulates the immune response facilitating the spread of the tuberculosis disease. Here, we demonstrate that a previously uncharacterized secreted protein from Mtb, Rv1813c, manipulates the host metabolism by targeting mitochondria. When expressed in eukaryotic cells, the protein is delivered to the mitochondrial intermembrane space and promotes the enhancement of host ATP production by boosting the oxidative phosphorylation metabolic pathway. Furthermore, the release of cytochrome c from mitochondria, an early apoptotic event in response to short-term oxidative stress, is delayed in Rv1813c-expressing cells. This study reveals a novel class of mitochondria targeting effectors from Mtb that might participate in host cell metabolic reprogramming and apoptosis control during Mtb infections. IMPORTANCE In this article, using a combination of techniques (bioinformatics, structural biology, and cell biology), we identified and characterized a new class of effectors present only in intracellular mycobacteria. These proteins specifically target host cell mitochondria when ectopically expressed in cells. We showed that one member of this family (Rv1813c) affects mitochondria metabolism in a way that might twist the immune response. This effector also inhibits the cytochrome c exit from mitochondria, suggesting that it might alter normal host cell apoptotic capacities, one of the first defenses of immune cells against Mtb infection.
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Affiliation(s)
- Marianne Martin
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Angelique deVisch
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Yves-Marie Boudehen
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse CNRS, UPS, Toulouse, France
| | - Philippe Barthe
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Claude Gutierrez
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse CNRS, UPS, Toulouse, France
| | - Obolbek Turapov
- Leicester Tuberculosis Research Group, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Talip Aydogan
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Laurène Heriaud
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Jerome Gracy
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
| | - Olivier Neyrolles
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse CNRS, UPS, Toulouse, France
| | - Galina V. Mukamolova
- Leicester Tuberculosis Research Group, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - François Letourneur
- Laboratory of Pathogen Host Interactions, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Martin Cohen-Gonsaud
- Centre de Biochimie Structurale, CNRS, INSERM, Université de Montpellier, Montpellier, France
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4
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Al-Jourani O, Benedict ST, Ross J, Layton AJ, van der Peet P, Marando VM, Bailey NP, Heunis T, Manion J, Mensitieri F, Franklin A, Abellon-Ruiz J, Oram SL, Parsons L, Cartmell A, Wright GSA, Baslé A, Trost M, Henrissat B, Munoz-Munoz J, Hirt RP, Kiessling LL, Lovering AL, Williams SJ, Lowe EC, Moynihan PJ. Identification of D-arabinan-degrading enzymes in mycobacteria. Nat Commun 2023; 14:2233. [PMID: 37076525 PMCID: PMC10115798 DOI: 10.1038/s41467-023-37839-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 03/31/2023] [Indexed: 04/21/2023] Open
Abstract
Bacterial cell growth and division require the coordinated action of enzymes that synthesize and degrade cell wall polymers. Here, we identify enzymes that cleave the D-arabinan core of arabinogalactan, an unusual component of the cell wall of Mycobacterium tuberculosis and other mycobacteria. We screened 14 human gut-derived Bacteroidetes for arabinogalactan-degrading activities and identified four families of glycoside hydrolases with activity against the D-arabinan or D-galactan components of arabinogalactan. Using one of these isolates with exo-D-galactofuranosidase activity, we generated enriched D-arabinan and used it to identify a strain of Dysgonomonas gadei as a D-arabinan degrader. This enabled the discovery of endo- and exo-acting enzymes that cleave D-arabinan, including members of the DUF2961 family (GH172) and a family of glycoside hydrolases (DUF4185/GH183) that display endo-D-arabinofuranase activity and are conserved in mycobacteria and other microbes. Mycobacterial genomes encode two conserved endo-D-arabinanases with different preferences for the D-arabinan-containing cell wall components arabinogalactan and lipoarabinomannan, suggesting they are important for cell wall modification and/or degradation. The discovery of these enzymes will support future studies into the structure and function of the mycobacterial cell wall.
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Affiliation(s)
- Omar Al-Jourani
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Samuel T Benedict
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jennifer Ross
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Abigail J Layton
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Phillip van der Peet
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Victoria M Marando
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
- The Broad Institute of Harvard and MIT, Cambridge, MA, USA The Koch Integrative Cancer Research Institute, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicholas P Bailey
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Tiaan Heunis
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Joseph Manion
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Francesca Mensitieri
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Aaron Franklin
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Javier Abellon-Ruiz
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Sophia L Oram
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Lauren Parsons
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Alan Cartmell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | | | - Arnaud Baslé
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Matthias Trost
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Bernard Henrissat
- Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
- Department of Biotechnology and Biomedicine (DTU Bioengineering), Technical University of Denmark, 2800 Kgs, Lyngby, Denmark
| | - Jose Munoz-Munoz
- Microbial Enzymology Group, Department of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Robert P Hirt
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Laura L Kiessling
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Andrew L Lovering
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Elisabeth C Lowe
- Newcastle University Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
| | - Patrick J Moynihan
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
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5
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Jaisinghani N, Previti ML, Andrade J, Askenazi M, Ueberheide B, Seeliger JC. Cell wall proteomics in live Mycobacterium tuberculosis uncovers exposure of ESX substrates to the periplasm. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.29.534792. [PMID: 37034674 PMCID: PMC10081232 DOI: 10.1101/2023.03.29.534792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
The cell wall of mycobacteria plays a key role in interactions with the environment and its ability to act as a selective filter is crucial to bacterial survival. Proteins in the cell wall enable this function by mediating the import and export of diverse metabolites from ions to lipids to proteins. Accurately identifying cell wall proteins is an important step in assigning function, especially as many mycobacterial proteins lack functionally characterized homologues. Current methods for protein localization have inherent limitations that reduce accuracy. Here we showed that protein tagging by the engineered peroxidase APEX2 within live Mycobacterium tuberculosis enabled the accurate identification of the cytosolic and cell wall proteomes. Our data indicate that substrates of the virulence-associated Type VII ESX secretion system are exposed to the Mtb periplasm, providing insight into the currently unknown mechanism by which these proteins cross the mycobacterial cell envelope.
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Affiliation(s)
- Neetika Jaisinghani
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Mary L Previti
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Joshua Andrade
- Proteomics Laboratory, New York University Grossman School of Medicine, New York, New York, USA
| | | | - Beatrix Ueberheide
- Proteomics Laboratory, New York University Grossman School of Medicine, New York, New York, USA
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, New York, USA
| | - Jessica C Seeliger
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, USA
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6
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Karlikowska M, Singh A, Bhatt A, Ott S, Bottrill AR, Besra GS, Fullam E. Biochemical and phenotypic characterisation of the Mycobacterium smegmatis transporter UspABC. Cell Surf 2021; 7:100052. [PMID: 34296047 PMCID: PMC8281650 DOI: 10.1016/j.tcsw.2021.100052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/02/2021] [Accepted: 04/03/2021] [Indexed: 11/08/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is an intracellular human pathogen that has evolved to survive in a nutrient limited environment within the host for decades. Accordingly, Mtb has developed strategies to acquire scarce nutrients and the mycobacterial transporter systems provide an important route for the import of key energy sources. However, the physiological role of the Mtb transporters and their substrate preference(s) are poorly characterised. Previous studies have established that the Mtb UspC solute-binding domain recognises amino- and phosphorylated-sugars, indicating that the mycobacterial UspABC transporter plays a key role in the import of peptidoglycan precursors. Herein, we have used a wide array of approaches to investigate the role of UspABC in Mycobacterium smegmatis by analysis of mutant strains that either lack the solute binding domain: ΔuspC or the entire transport complex: ΔuspABC. Analysis of mycobacterial transcripts shows that the uspABC system is functionally expressed in mycobacteria as a contiguous reading frame. Topology mapping confirms an Nin-Cin orientation of the UspAB integral membrane spanning domains. Phenotypic microarray profiling of commercially available sugars suggests, unexpectedly, that the uspC and ΔuspABC mutants had different carbon utilisation profiles and that neither strain utilised glucose-1-phosphate. Furthermore, proteomics analysis showed an alteration in the abundance of proteins involved in sugar and lipid metabolism, crucial for cell envelope synthesis, and we propose that UspABC has an important role in determining the interplay between these pathways.
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Affiliation(s)
| | - Albel Singh
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Apoorva Bhatt
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Sascha Ott
- Warwick Medical School, University of Warwick, CV4 7AL, UK
- Bioinformatics Research Technology Platform, University of Warwick, Coventry CV4 7AL, UK
| | | | - Gurdyal S. Besra
- Institute of Microbiology & Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Elizabeth Fullam
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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7
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Cai X, Liu L, Qiu C, Wen C, He Y, Cui Y, Li S, Zhang X, Zhang L, Tian C, Bi L, Zhou ZH, Gong W. Identification and architecture of a putative secretion tube across mycobacterial outer envelope. SCIENCE ADVANCES 2021; 7:7/34/eabg5656. [PMID: 34417177 PMCID: PMC8378821 DOI: 10.1126/sciadv.abg5656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Tuberculosis-causing mycobacteria have thick cell-wall and capsule layers that are formed from complex structures. Protein secretion across these barriers depends on a specialized protein secretion system, but none has been reported. We show that Mycobacterium tuberculosis Rv3705c and its homologous MSMEG_6251 in Mycobacterium smegmatis are tube-forming proteins in the mycobacterial envelope (TiME). Crystallographic and cryo-EM structures of these two proteins show that both proteins form rotationally symmetric rings. Two layers of TiME rings pack together in a tail-to-tail manner into a ring-shaped complex, which, in turn, stacks together to form tubes. M. smegmatis TiME was detected mainly in the cell wall and capsule. Knocking out the TiME gene markedly decreased the amount of secreted protein in the M. smegmatis culture medium, and expression of this gene in knocked-out strain partially restored the level of secreted protein. Our structure and functional data thus suggest that TiME forms a protein transport tube across the mycobacterial outer envelope.
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Affiliation(s)
- Xiaoying Cai
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Lei Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
| | - Chunhong Qiu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Chongzheng Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
| | - Yao He
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Siyu Li
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Xuan Zhang
- Institute of Health Science, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, China
| | - Longhua Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Changlin Tian
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Lijun Bi
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA.
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
| | - Weimin Gong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
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8
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Li X, Wang M, Ming S, Liang Z, Zhan X, Cao C, Liang S, Liu Q, Shang Y, Lao J, Zhang S, Kuang L, Geng L, Wu Z, Wu M, Gong S, Wu Y. TARM-1 Is Critical for Macrophage Activation and Th1 Response in Mycobacterium tuberculosis Infection. THE JOURNAL OF IMMUNOLOGY 2021; 207:234-243. [PMID: 34183366 DOI: 10.4049/jimmunol.2001037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 04/29/2021] [Indexed: 12/15/2022]
Abstract
T cell-interacting activating receptor on myeloid cells 1 (TARM-1) is a novel leukocyte receptor expressed in neutrophils and macrophages. It plays an important role in proinflammatory response in acute bacterial infection, but its immunomodulatory effects on chronic Mycobacterium tuberculosis infections remain unclear. TARM-1 expression was significantly upregulated on CD14high monocytes from patients with active pulmonary tuberculosis (TB) as compared that on cells from patients with latent TB or from healthy control subjects. Small interfering RNA knockdown of TARM-1 reduced expression levels of proinflammatory cytokines IL-12, IL-18, IL-1β, and IL-8 in M. tuberculosis-infected macrophages, as well as that of HLA-DR and costimulatory molecules CD83, CD86, and CD40. Moreover, TARM-1 enhanced phagocytosis and intracellular killing of M. tuberculosis through upregulating reactive oxygen species. In an in vitro monocyte and T cell coculture system, blockade of TARM-1 activity by TARM-1 blocking peptide suppressed CD4+ T cell activation and proliferation. Finally, administration of TARM-1 blocking peptide in a mouse model of M. tuberculosis infection increased bacterial load and lung pathology, which was associated with decreased macrophage activation and IFN-γ production by T cell. Taken together, these results, to our knowledge, demonstrate a novel immune protective role of TARM-1 in M. tuberculosis infection and provide a potential therapeutic target for TB disease.
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Affiliation(s)
- Xingyu Li
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Manni Wang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Siqi Ming
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Zibin Liang
- Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Thoracic Oncology, The Cancer Center of the Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Xiaoxia Zhan
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Laboratory Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong Province, China
| | - Can Cao
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
| | - Sipin Liang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Qiaojuan Liu
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Yuqi Shang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Juanfeng Lao
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Shunxian Zhang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
| | - Liangjian Kuang
- Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China
| | - Lanlan Geng
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
| | - Zhilong Wu
- The Fourth People's Hospital of Foshan, Foshan, Guangdong Province, China
| | - Minhao Wu
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
| | - Sitang Gong
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
| | - Yongjian Wu
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center (Guangzhou), The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China; .,Center for Infection and Immunity, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, Guangdong Province, China.,Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Institute of Pediatrics, Guangzhou Medical University, Guangzhou, Guangdong Province, China; and
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9
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Evidence for the Mycobacterial Mce4 Transporter Being a Multiprotein Complex. J Bacteriol 2021; 203:JB.00685-20. [PMID: 33649150 DOI: 10.1128/jb.00685-20] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/24/2021] [Indexed: 01/01/2023] Open
Abstract
Mycobacteria possess Mce transporters that import lipids and are thought to function analogously to ATP-binding cassette (ABC) transporters. However, whereas ABC transporters import substrates using a single solute-binding protein (SBP) to deliver a substrate to permease proteins in the membrane, mycobacterial Mce transporters have a potential for six SBPs (MceA to MceF) working with a pair of permeases (YrbEA and YrbEB), a cytoplasmic ATPase (MceG), and multiple Mce-associated membrane (Mam) and orphaned Mam (Omam) proteins to transport lipids. In this study, we used the model mycobacterium Mycobacterium smegmatis to study the requirement for individual Mce, Mam, and Omam proteins in Mce4 transport of cholesterol. All of the Mce4 and Mam4 proteins we investigated were required for cholesterol uptake. However, not all Omam proteins, which are encoded by genes outside mce loci, proved to contribute to cholesterol import. OmamA and OmamB were required for cholesterol import, while OmamC, OmamD, OmamE, and OmamF were not. In the absence of any single Mce4, Mam4, or Omam protein that we tested, the abundance of Mce4A and Mce4E declined. This relationship between the levels of Mce4A and Mce4E and these additional proteins suggests a network of interactions that assemble and/or stabilize a multiprotein Mce4 transporter complex. Further support for Mce transporters being multiprotein complexes was obtained by immunoprecipitation-mass spectrometry, in which we identified every single Mce, YrbE, MceG, Mam, and Omam protein with a role in cholesterol transport as associating with Mce4A. This study represents the first time any of these Mce4 transporter proteins has been shown to associate.IMPORTANCE How lipids travel between membranes of diderm bacteria is a challenging mechanistic question because lipids, which are hydrophobic molecules, must traverse a hydrophilic periplasm. This question is even more complex for mycobacteria, which have a unique cell envelope that is highly impermeable to molecules. A growing body of knowledge identifies Mce transporters as lipid importers for mycobacteria. Here, using protein stability experiments and immunoprecipitation-mass spectrometry, we provide evidence for mycobacterial Mce transporters existing as multiprotein complexes.
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10
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Nicholson KR, Mousseau CB, Champion MM, Champion PA. The genetic proteome: Using genetics to inform the proteome of mycobacterial pathogens. PLoS Pathog 2021; 17:e1009124. [PMID: 33411813 PMCID: PMC7790235 DOI: 10.1371/journal.ppat.1009124] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mycobacterial pathogens pose a sustained threat to human health. There is a critical need for new diagnostics, therapeutics, and vaccines targeting both tuberculous and nontuberculous mycobacterial species. Understanding the basic mechanisms used by diverse mycobacterial species to cause disease will facilitate efforts to design new approaches toward detection, treatment, and prevention of mycobacterial disease. Molecular, genetic, and biochemical approaches have been widely employed to define fundamental aspects of mycobacterial physiology and virulence. The recent expansion of genetic tools in mycobacteria has further increased the accessibility of forward genetic approaches. Proteomics has also emerged as a powerful approach to further our understanding of diverse mycobacterial species. Detection of large numbers of proteins and their modifications from complex mixtures of mycobacterial proteins is now routine, with efforts of quantification of these datasets becoming more robust. In this review, we discuss the “genetic proteome,” how the power of genetics, molecular biology, and biochemistry informs and amplifies the quality of subsequent analytical approaches and maximizes the potential of hypothesis-driven mycobacterial research. Published proteomics datasets can be used for hypothesis generation and effective post hoc supplementation to experimental data. Overall, we highlight how the integration of proteomics, genetic, molecular, and biochemical approaches can be employed successfully to define fundamental aspects of mycobacterial pathobiology.
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Affiliation(s)
- Kathleen R. Nicholson
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - C. Bruce Mousseau
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Matthew M. Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, United States of America
- Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame Indiana, United States of America
- * E-mail: (MMC); (PAC)
| | - Patricia A. Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- Boler-Parseghian Center for Rare and Neglected Diseases, University of Notre Dame, Notre Dame Indiana, United States of America
- * E-mail: (MMC); (PAC)
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11
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Role of LmeA, a Mycobacterial Periplasmic Protein, in Maintaining the Mannosyltransferase MptA and Its Product Lipomannan under Stress. mSphere 2020; 5:5/6/e01039-20. [PMID: 33148829 PMCID: PMC7643837 DOI: 10.1128/msphere.01039-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria. The mycobacterial cell envelope has a diderm structure, composed of an outer mycomembrane, an arabinogalactan-peptidoglycan cell wall, a periplasm, and an inner membrane. Lipomannan (LM) and lipoarabinomannan (LAM) are structural and immunomodulatory components of this cell envelope. LM/LAM biosynthesis involves a number of mannosyltransferases and acyltransferases, and MptA is an α1,6-mannosyltransferase involved in the final extension of the mannan chain. Recently, we reported the periplasmic protein LmeA being involved in the maturation of the mannan backbone in Mycobacterium smegmatis. Here, we examined the role of LmeA under stress conditions. We found that lmeA transcription was upregulated under two stress conditions: stationary growth phase and nutrient starvation. Under both conditions, LAM was decreased, but LM was relatively stable, suggesting that maintaining the cellular level of LM under stress is important. Surprisingly, the protein levels of MptA were decreased in an lmeA deletion (ΔlmeA) mutant under both stress conditions. The transcript levels of mptA in the ΔlmeA mutant were similar to or even higher than those in the wild type, indicating that the decrease of MptA protein was a posttranscriptional event. The ΔlmeA mutant was unable to maintain the cellular level of LM under stress, consistent with the decrease in MptA. Even during active growth, overexpression of LmeA led the cells to produce more LM and become more resistant to several antibiotics. Altogether, our study reveals the roles of LmeA in the homeostasis of the MptA mannosyltransferase, particularly under stress conditions, ensuring the stable expression of LM and the maintenance of cell envelope integrity. IMPORTANCE Mycobacteria differentially regulate the cellular amounts of lipoglycans in response to environmental changes, but the molecular mechanisms of this regulation remain unknown. Here, we demonstrate that cellular lipoarabinomannan (LAM) levels rapidly decline under two stress conditions, stationary growth phase and nutrient starvation, while the levels of another related lipoglycan, lipomannan (LM), stay relatively constant. The persistence of LM under stress correlated with the maintenance of two key mannosyltransferases, MptA and MptC, in the LM biosynthetic pathway. We further showed that the stress exposures lead to the upregulation of lmeA gene expression and that the periplasmic protein LmeA plays a key role in maintaining the enzyme MptA and its product LM under stress conditions. These findings reveal new aspects of how lipoglycan biosynthesis is regulated under stress conditions in mycobacteria.
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12
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Pediatric Tuberculosis: The Impact of "Omics" on Diagnostics Development. Int J Mol Sci 2020; 21:ijms21196979. [PMID: 32977381 PMCID: PMC7582311 DOI: 10.3390/ijms21196979] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 02/07/2023] Open
Abstract
Tuberculosis (TB) is a major public health concern for all ages. However, the disease presents a larger challenge in pediatric populations, partially owing to the lack of reliable diagnostic standards for the early identification of infection. Currently, there are no biomarkers that have been clinically validated for use in pediatric TB diagnosis. Identification and validation of biomarkers could provide critical information on prognosis of disease, and response to treatment. In this review, we discuss how the “omics” approach has influenced biomarker discovery and the advancement of a next generation rapid point-of-care diagnostic for TB, with special emphasis on pediatric disease. Limitations of current published studies and the barriers to their implementation into the field will be thoroughly reviewed within this article in hopes of highlighting future avenues and needs for combating the problem of pediatric tuberculosis.
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13
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Harris MO, Pitzschke A. Plants make galls to accommodate foreigners: some are friends, most are foes. THE NEW PHYTOLOGIST 2020; 225:1852-1872. [PMID: 31774564 DOI: 10.1111/nph.16340] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 07/24/2019] [Indexed: 06/10/2023]
Abstract
At the colonization site of a foreign entity, plant cells alter their trajectory of growth and development. The resulting structure - a plant gall - accommodates various needs of the foreigner, which are phylogenetically diverse: viruses, bacteria, protozoa, oomycetes, true fungi, parasitic plants, and many types of animals, including rotifers, nematodes, insects, and mites. The plant species that make galls also are diverse. We assume gall production costs the plant. All is well if the foreigner provides a gift that makes up for the cost. Nitrogen-fixing nodule-inducing bacteria provide nutritional services. Gall wasps pollinate fig trees. Unfortunately for plants, most galls are made for foes, some of which are deeply studied pathogens and pests: Agrobacterium tumefaciens, Rhodococcus fascians, Xanthomonas citri, Pseudomonas savastanoi, Pantoea agglomerans, 'Candidatus' phytoplasma, rust fungi, Ustilago smuts, root knot and cyst nematodes, and gall midges. Galls are an understudied phenomenon in plant developmental biology. We propose gall inception for discovering unifying features of the galls that plants make for friends and foes, talk about molecules that plants and gall-inducers use to get what they want from each other, raise the question of whether plants colonized by arbuscular mycorrhizal fungi respond in a gall-like manner, and present a research agenda.
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Affiliation(s)
- Marion O Harris
- Department of Entomology, North Dakota State University, Fargo, ND, 58014, USA
| | - Andrea Pitzschke
- Department of Biosciences, Salzburg University, Hellbrunner Strasse 34, A-5020, Salzburg, Austria
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14
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Stamm CE, Pasko BL, Chaisavaneeyakorn S, Franco LH, Nair VR, Weigele BA, Alto NM, Shiloh MU. Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector. mSphere 2019; 4:e00354-19. [PMID: 31167949 PMCID: PMC6553557 DOI: 10.1128/msphere.00354-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 05/19/2019] [Indexed: 02/07/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is one of the most successful human pathogens. One reason for its success is that Mtb can reside within host macrophages, a cell type that normally functions to phagocytose and destroy infectious bacteria. However, Mtb is able to evade macrophage defenses in order to survive for prolonged periods of time. Many intracellular pathogens secrete virulence factors targeting host membranes and organelles to remodel their intracellular environmental niche. We hypothesized that Mtb secreted proteins that target host membranes are vital for Mtb to adapt to and manipulate the host environment for survival. Thus, we characterized 200 secreted proteins from Mtb for their ability to associate with eukaryotic membranes using a unique temperature-sensitive yeast screen and to manipulate host trafficking pathways using a modified inducible secretion screen. We identified five Mtb secreted proteins that both associated with eukaryotic membranes and altered the host secretory pathway. One of these secreted proteins, Mpt64, localized to the endoplasmic reticulum during Mtb infection of murine and human macrophages and impaired the unfolded protein response in macrophages. These data highlight the importance of secreted proteins in Mtb pathogenesis and provide a basis for further investigation into their molecular mechanisms.IMPORTANCE Advances have been made to identify secreted proteins of Mycobacterium tuberculosis during animal infections. These data, combined with transposon screens identifying genes important for M. tuberculosis virulence, have generated a vast resource of potential M. tuberculosis virulence proteins. However, the function of many of these proteins in M. tuberculosis pathogenesis remains elusive. We have integrated three cell biological screens to characterize nearly 200 M. tuberculosis secreted proteins for eukaryotic membrane binding, host subcellular localization, and interactions with host vesicular trafficking. In addition, we observed the localization of one secreted protein, Mpt64, to the endoplasmic reticulum (ER) during M. tuberculosis infection of macrophages. Interestingly, although Mpt64 is exported by the Sec pathway, its delivery into host cells was dependent upon the action of the type VII secretion system. Finally, we observed that Mpt64 impairs the ER-mediated unfolded protein response in macrophages.
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Affiliation(s)
- Chelsea E Stamm
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Breanna L Pasko
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sujittra Chaisavaneeyakorn
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Luis H Franco
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Center for Autophagy Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Vidhya R Nair
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Bethany A Weigele
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Neal M Alto
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michael U Shiloh
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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15
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Ates LS, Sayes F, Frigui W, Ummels R, Damen MPM, Bottai D, Behr MA, van Heijst JWJ, Bitter W, Majlessi L, Brosch R. RD5-mediated lack of PE_PGRS and PPE-MPTR export in BCG vaccine strains results in strong reduction of antigenic repertoire but little impact on protection. PLoS Pathog 2018; 14:e1007139. [PMID: 29912964 PMCID: PMC6023246 DOI: 10.1371/journal.ppat.1007139] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 06/28/2018] [Accepted: 06/05/2018] [Indexed: 01/03/2023] Open
Abstract
Tuberculosis is the deadliest infectious disease worldwide. Although the BCG vaccine is widely used, it does not efficiently protect against pulmonary tuberculosis and an improved tuberculosis vaccine is therefore urgently needed. Mycobacterium tuberculosis uses different ESX/Type VII secretion (T7S) systems to transport proteins important for virulence and host immune responses. We recently reported that secretion of T7S substrates belonging to the mycobacteria-specific Pro-Glu (PE) and Pro-Pro-Glu (PPE) proteins of the PGRS (polymorphic GC-rich sequences) and MPTR (major polymorphic tandem repeat) subfamilies required both a functional ESX-5 system and a functional PPE38/71 protein for secretion. Inactivation of ppe38/71 and the resulting loss of PE_PGRS/PPE-MPTR secretion were linked to increased virulence of M. tuberculosis strains. Here, we show that a predicted total of 89 PE_PGRS/PPE-MPTR surface proteins are not exported by certain animal-adapted strains of the M. tuberculosis complex including M. bovis. This Δppe38/71-associated secretion defect therefore also occurs in the M. bovis-derived tuberculosis vaccine BCG and could be partially restored by introduction of the M. tuberculosis ppe38-locus. Epitope mapping of the PPE-MPTR protein PPE10, further allowed us to monitor T-cell responses in splenocytes from BCG/M. tuberculosis immunized mice, confirming the dependence of PPE10-specific immune-induction on ESX-5/PPE38-mediated secretion. Restoration of PE_PGRS/PPE-MPTR secretion in recombinant BCG neither altered global antigenic presentation or activation of innate immune cells, nor protective efficacy in two different mouse vaccination-infection models. This unexpected finding stimulates a reassessment of the immunomodulatory properties of PE_PGRS/PPE-MPTR proteins, some of which are contained in vaccine formulations currently in clinical evaluation. One of the major findings of the pioneering Mycobacterium tuberculosis H37Rv genome sequencing project was the identification of the highly abundant PE and PPE proteins, named after their N-terminal motifs Pro–Glu (PE) or Pro–Pro–Glu (PPE). Within the 20 years of research since then, many claims were made that PE/PPE proteins, including the two large subgroups encoded by repetitive sequences with very high GC content (PE_PGRS and PPE-MPTR families), are exported to the bacterial surface or beyond, and show broad immunomodulatory impact on host-pathogen interaction. We thus screened strains from different branches of the M. tuberculosis complex, including the attenuated Mycobacterium bovis BCG vaccine strains, for their capacity to export PE_PGRS/PPE-MPTR proteins. Strikingly, we found that BCG strains were unable to export the plethora of PE_PGRS/PPE-MPTR proteins due to the absence of the region of difference RD5, which in M. tuberculosis encodes PPE38, required for PE_PGRS/PPE-MPTR export. Surprisingly, the restoration of PE_PGRS/PPE-MPTR export by genetic complementation in recombinant BCG did not result in immunomodulatory changes or altered protection in mouse models. Our results thus put into perspective the numerous reports on virulence-associated immunomodulatory impact of individual PE_PGRS and PPE-MPTR proteins and open novel questions on their biological function(s).
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Affiliation(s)
- Louis S. Ates
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- * E-mail: (LSA); (RB)
| | - Fadel Sayes
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Wafa Frigui
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Roy Ummels
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
| | - Merel P. M. Damen
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit, Amsterdam, the Netherlands
| | - Daria Bottai
- University of Pisa, Department of Biology, Pisa, Italy
| | - Marcel A. Behr
- McGill International TB Centre, Infectious Diseases and Immunity in Global Health Program at the McGill University Health Centre Research Institute, Montreal, Canada
| | - Jeroen W. J. van Heijst
- Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Prevention, VU University Medical Center, Amsterdam, the Netherlands
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit, Amsterdam, the Netherlands
| | - Laleh Majlessi
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
| | - Roland Brosch
- Institut Pasteur, Unit for Integrated Mycobacterial Pathogenomics, CNRS UMR3525, Paris, France
- * E-mail: (LSA); (RB)
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16
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Ganapathy US, Bai L, Wei L, Eckartt KA, Lett CM, Previti ML, Carrico IS, Seeliger JC. Compartment-Specific Labeling of Bacterial Periplasmic Proteins by Peroxidase-Mediated Biotinylation. ACS Infect Dis 2018; 4:918-925. [PMID: 29708735 DOI: 10.1021/acsinfecdis.8b00044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The study of the bacterial periplasm requires techniques with sufficient spatial resolution and sensitivity to resolve the components and processes within this subcellular compartment. Peroxidase-mediated biotinylation has enabled targeted labeling of proteins within subcellular compartments of mammalian cells. We investigated whether this methodology could be applied to the bacterial periplasm. In this study, we demonstrated that peroxidase-mediated biotinylation can be performed in mycobacteria and Escherichia coli. To eliminate detection artifacts from natively biotinylated mycobacterial proteins, we validated two alternative labeling substrates, tyramide azide and tyramide alkyne, which enable biotin-independent detection of labeled proteins. We also targeted peroxidase expression to the periplasm, resulting in compartment-specific labeling of periplasmic versus cytoplasmic proteins in mycobacteria. Finally, we showed that this method can be used to validate protein relocalization to the cytoplasm upon removal of a secretion signal. This novel application of peroxidase-mediated protein labeling will advance efforts to characterize the role of the periplasm in bacterial physiology and pathogenesis.
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17
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Rahlwes KC, Ha SA, Motooka D, Mayfield JA, Baumoel LR, Strickland JN, Torres-Ocampo AP, Nakamura S, Morita YS. The cell envelope-associated phospholipid-binding protein LmeA is required for mannan polymerization in mycobacteria. J Biol Chem 2017; 292:17407-17417. [PMID: 28855252 DOI: 10.1074/jbc.m117.804377] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/28/2017] [Indexed: 11/06/2022] Open
Abstract
The integrity of the distinguishing, multilaminate cell envelope surrounding mycobacteria is critical to their survival and pathogenesis. The prevalence of phosphatidylinositol mannosides in the cell envelope suggests an important role in the mycobacterial life cycle. Indeed, deletion of the pimE gene (ΔpimE) encoding the first committed step in phosphatidylinositol hexamannoside biosynthesis in Mycobacterium smegmatis results in the formation of smaller colonies than wild-type colonies on Middlebrook 7H10 agar. To further investigate potential contributors to cell-envelope mannan biosynthesis while taking advantage of this colony morphology defect, we isolated spontaneous suppressor mutants of ΔpimE that reverted to wild-type colony size. Of 22 suppressor mutants, 6 accumulated significantly shorter lipomannan or lipoarabinomannan. Genome sequencing of these mutants revealed mutations in genes involved in the lipomannan/lipoarabinomannan biosynthesis, such as those encoding the arabinosyltransferase EmbC and the mannosyltransferase MptA. Furthermore, we identified three mutants carrying a mutation in a previously uncharacterized gene, MSMEG_5785, that we designated lmeA Complementation of these suppressor mutants with lmeA restored the original ΔpimE phenotypes and deletion of lmeA in wild-type M. smegmatis resulted in smaller lipomannan, as observed in the suppressor mutants. LmeA carries a predicted N-terminal signal peptide, and density gradient fractionation and detergent extractability experiments indicated that LmeA localizes to the cell envelope. Using a lipid ELISA, we found that LmeA binds to plasma membrane phospholipids, such as phosphatidylethanolamine and phosphatidylinositol. LmeA is widespread throughout the Corynebacteriales; therefore, we concluded that LmeA is an evolutionarily conserved cell-envelope protein critical for controlling the mannan chain length of lipomannan/lipoarabinomannan.
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Affiliation(s)
- Kathryn C Rahlwes
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Stephanie A Ha
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Daisuke Motooka
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Jacob A Mayfield
- the Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02445
| | - Lisa R Baumoel
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Justin N Strickland
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Ana P Torres-Ocampo
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003
| | - Shota Nakamura
- the Department of Infection Metagenomics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Yasu S Morita
- From the Department of Microbiology, University of Massachusetts, Amherst, MA 01003,
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18
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Maffei B, Francetic O, Subtil A. Tracking Proteins Secreted by Bacteria: What's in the Toolbox? Front Cell Infect Microbiol 2017; 7:221. [PMID: 28620586 PMCID: PMC5449463 DOI: 10.3389/fcimb.2017.00221] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/15/2017] [Indexed: 01/14/2023] Open
Abstract
Bacteria have acquired multiple systems to expose proteins on their surface, release them in the extracellular environment or even inject them into a neighboring cell. Protein secretion has a high adaptive value and secreted proteins are implicated in many functions, which are often essential for bacterial fitness. Several secreted proteins or secretion machineries have been extensively studied as potential drug targets. It is therefore important to identify the secretion substrates, to understand how they are specifically recognized by the secretion machineries, and how transport through these machineries occurs. The purpose of this review is to provide an overview of the biochemical, genetic and imaging tools that have been developed to evaluate protein secretion in a qualitative or quantitative manner. After a brief overview of the different tools available, we will illustrate their advantages and limitations through a discussion of some of the current open questions related to protein secretion. We will start with the question of the identification of secreted proteins, which for many bacteria remains a critical initial step toward a better understanding of their interactions with the environment. We will then illustrate our toolbox by reporting how these tools have been applied to better understand how substrates are recognized by their cognate machinery, and how secretion proceeds. Finally, we will highlight recent approaches that aim at investigating secretion in real time, and in complex environments such as a tissue or an organism.
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Affiliation(s)
- Benoit Maffei
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut PasteurParis, France.,Centre National de la Recherche Scientifique UMR3691Paris, France
| | - Olivera Francetic
- Unité de Biochimie des Interactions Macromoléculaires, Institut PasteurParis, France.,Centre National de la Recherche Scientifique ERL6002Paris, France
| | - Agathe Subtil
- Unité de Biologie Cellulaire de l'Infection Microbienne, Institut PasteurParis, France.,Centre National de la Recherche Scientifique UMR3691Paris, France
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