1
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Prest RJ, Korotkov KV, Champion PA. The regulatory functions of ESX-1 substrates, EspE and EspF, are separable from secretion. J Bacteriol 2024; 206:e0027124. [PMID: 39136451 PMCID: PMC11411940 DOI: 10.1128/jb.00271-24] [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: 07/03/2024] [Accepted: 07/11/2024] [Indexed: 09/07/2024] Open
Abstract
Pathogenic mycobacteria are a significant global health burden. The ESX-1 secretion system is essential for mycobacterial pathogenesis. The secretion of ESX-1 substrates is required for phagosomal lysis, which allows the bacteria to enter the macrophage cytoplasm, induce a Type I IFN response, and spread to new host cells. EspE and EspF are dual-functioning ESX-1 substrates. Inside the mycobacterial cell, they regulate transcription of ESX-1-associated genes. Following secretion, EspE and EspF are essential for lytic activity. The link between EspE/F secretion and regulatory function has not been investigated. We investigated the relationship between EspE and EspF using molecular genetics in Mycobacterium marinum, a non-tuberculous mycobacterial species that serves as an established model for ESX-1 secretion and function in Mycobacterium tuberculosis. Our data support that EspE and EspF, which require each other for secretion, directly interact. The disruption of the predicted protein-protein interaction abrogates hemolytic activity and secretion but does not impact their gene regulatory activities in the mycobacterial cell. In addition, we predict a direct protein-protein interaction between the EsxA/EsxB heterodimer and EspF. Our data support that the EspF/EsxA interaction is also required for hemolytic activity and EspE secretion. Our study sheds light on the intricate molecular mechanisms governing the interactions between ESX-1 substrates, regulatory function, and ESX-1 secretion, moving the field forward.IMPORTANCETuberculosis (TB), caused by Mycobacterium tuberculosis, is a historical and pervasive disease responsible for millions of deaths annually. The rise of antibiotic and treatment-resistant TB, as well as the rise of infection by non-tuberculous mycobacterial species, calls for a better understanding of pathogenic mycobacteria. The ESX-1 secreted substrates, EspE and EspF, are required for mycobacterial virulence and may be responsible for phagosomal lysis. This study focuses on the mechanism of EspE and EspF secretion from the mycobacterial cell.
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Affiliation(s)
- Rebecca J Prest
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Konstantin V Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Patricia A Champion
- Department of Biological Sciences, Eck Institute for Global Health, 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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2
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Yan L, Lai HY, Leung TCN, Cheng HF, Chen X, Tsui SKW, Ngai SM, Au SWN. PE/PPE Proteome and ESX-5 Substrate Spectrum in Mycobacterium marinum. Int J Mol Sci 2024; 25:9550. [PMID: 39273496 PMCID: PMC11395111 DOI: 10.3390/ijms25179550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2024] [Revised: 08/05/2024] [Accepted: 08/07/2024] [Indexed: 09/15/2024] Open
Abstract
PE/PPE proteins secreted by the ESX-5 type VII secretion system constitute a major protein repertoire in pathogenic mycobacteria and are essential for bacterial survival, pathogenicity, and host-pathogen interaction; however, little is known about their expression and secretion. The scarcity of arginine and lysine residues in PE/PPE protein sequences and the high homology of their N-terminal domains limit protein identification using classical trypsin-based proteomic methods. This study used endoproteinase AspN and trypsin to characterize the proteome of Mycobacterium marinum. Twenty-seven PE/PPE proteins were uniquely identified in AspN digests, especially PE_PGRS proteins. These treatments allowed the identification of approximately 50% of the PE/PPE pool encoded in the genome. Moreover, EspG5 pulldown assays retrieved 44 ESX-5-associated PPE proteins, covering 85% of the PPE pool in the identified proteome. The identification of PE/PE_PGRS proteins in the EspG5 interactome suggested the presence of PE-PPE pairs. The correlation analysis between protein abundance and phylogenetic relationships found potential PE/PPE pairs, indicating the presence of multiple PE/PE_PGRS partners in one PPE. We validated that EspG5 interacted with PPE31 and PPE32 and mapped critical residues for complex formation. The modified proteomic platform increases the coverage of PE/PPE proteins and elucidates the expression and localization of these proteins.
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Affiliation(s)
- Lili Yan
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Hiu Ying Lai
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Thomas Chun Ning Leung
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Hiu Fu Cheng
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Xin Chen
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Stephen Kwok Wing Tsui
- School of Biomedical Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Sai Ming Ngai
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
| | - Shannon Wing Ngor Au
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, Hong Kong 999077, China
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3
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Mousseau CB, Hu DD, Schultz SR, Champion MM. Quenching Trypsin Is Unnecessary in Filter-Based Bottom-Up Proteomics. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:2028-2031. [PMID: 38982799 PMCID: PMC11313428 DOI: 10.1021/jasms.4c00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/11/2024]
Abstract
Quenching digestions in proteomics prior to analysis is routine in order to eliminate residual protease activity. Residual activity leads to overdigestion, nonspecific star-activity, and back-exchange in isotopic 18O quantitation. Chemical and isobaric labeling (e.g., TMT/iTRAQ) of proteins or peptides for mass spectrometry-based proteomics is generally incompatible with ubiquitous postdigestion acidification. This necessitates buffer exchange and pH adjustments. We demonstrate that quenching is unnecessary with peptides generated from protein filter-traps, as trypsin activity and intact trypsin are negligible in the eluate from these preparations. Labeling can be directly performed on enzymatic digests from these methods, improving recovery, throughput, and ease of automation.
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Affiliation(s)
- C. Bruce Mousseau
- Department
of Chemistry and Biochemistry, andBerthiaume Institute for Precision
Health, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Daniel D. Hu
- Department
of Chemistry and Biochemistry, andBerthiaume Institute for Precision
Health, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Sadie R. Schultz
- Department
of Chemistry and Biochemistry, andBerthiaume Institute for Precision
Health, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Matthew M. Champion
- Department
of Chemistry and Biochemistry, andBerthiaume Institute for Precision
Health, University of Notre Dame, Notre Dame, Indiana 46556, United States
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4
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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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5
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Bates TA, Trank-Greene M, Nguyenla X, Anastas A, Gurmessa SK, Merutka IR, Dixon SD, Shumate A, Groncki AR, Parson MAH, Ingram JR, Barklis E, Burke JE, Shinde U, Ploegh HL, Tafesse FG. ESAT-6 undergoes self-association at phagosomal pH and an ESAT-6-specific nanobody restricts M. tuberculosis growth in macrophages. eLife 2024; 12:RP91930. [PMID: 38805257 PMCID: PMC11132683 DOI: 10.7554/elife.91930] [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: 05/29/2024] Open
Abstract
Mycobacterium tuberculosis (Mtb) is known to survive within macrophages by compromising the integrity of the phagosomal compartment in which it resides. This activity primarily relies on the ESX-1 secretion system, predominantly involving the protein duo ESAT-6 and CFP-10. CFP-10 likely acts as a chaperone, while ESAT-6 likely disrupts phagosomal membrane stability via a largely unknown mechanism. we employ a series of biochemical analyses, protein modeling techniques, and a novel ESAT-6-specific nanobody to gain insight into the ESAT-6's mode of action. First, we measure the binding kinetics of the tight 1:1 complex formed by ESAT-6 and CFP-10 at neutral pH. Subsequently, we demonstrate a rapid self-association of ESAT-6 into large complexes under acidic conditions, leading to the identification of a stable tetrameric ESAT-6 species. Using molecular dynamics simulations, we pinpoint the most probable interaction interface. Furthermore, we show that cytoplasmic expression of an anti-ESAT-6 nanobody blocks Mtb replication, thereby underlining the pivotal role of ESAT-6 in intracellular survival. Together, these data suggest that ESAT-6 acts by a pH-dependent mechanism to establish two-way communication between the cytoplasm and the Mtb-containing phagosome.
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Affiliation(s)
- Timothy A Bates
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Mila Trank-Greene
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Xammy Nguyenla
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Aidan Anastas
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Sintayehu K Gurmessa
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Ilaria R Merutka
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Shandee D Dixon
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Anthony Shumate
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science UniversityPortlandUnited States
| | - Abigail R Groncki
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - Matthew AH Parson
- Department of Biochemistry and Microbiology, University of VictoriaVictoriaCanada
| | - Jessica R Ingram
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical SchoolBostonUnited States
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
| | - John E Burke
- Department of Biochemistry and Microbiology, University of VictoriaVictoriaCanada
- Department of Biochemistry and Molecular Biology, The University of British ColumbiaVancouverCanada
| | - Ujwal Shinde
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science UniversityPortlandUnited States
| | - Hidde L Ploegh
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Harvard Medical SchoolBostonUnited States
| | - Fikadu G Tafesse
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences UniversityPortlandUnited States
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6
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Hu DD, Weaver SD, Collars OA, Champion PA, Champion MM. N-terminal proteomics of Mycobacterium marinum using bottom-up label-free quantitative analysis in data-dependent acquisition mode on a timsTOF Pro mass spectrometer. Microbiol Resour Announc 2024; 13:e0126323. [PMID: 38477461 PMCID: PMC11008207 DOI: 10.1128/mra.01263-23] [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: 12/21/2023] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
N-terminal acetylation in Mycobacterium tuberculosis is correlated with pathogenic activity. We used genomics and bottom-up proteomics to identify protein Emp1 as the sole acetyltransferase responsible for acetylation of EsxA, a known virulence factor. Using custom data analysis, we screened the proteome to identify 22 additional putative substrates of Emp1.
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Affiliation(s)
- Daniel D. Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Simon D. Weaver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Owen A. Collars
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Patricia A. Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew M. Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
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7
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Nicholson KR, Cronin RM, Prest RJ, Menon AR, Yang Y, Jennisch MK, Champion MM, Tobin DM, Champion PA. The antagonistic transcription factors, EspM and EspN, regulate the ESX-1 secretion system in M. marinum. mBio 2024; 15:e0335723. [PMID: 38445877 PMCID: PMC11005418 DOI: 10.1128/mbio.03357-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/13/2024] [Indexed: 03/07/2024] Open
Abstract
Bacterial pathogens use protein secretion systems to transport virulence factors and regulate gene expression. Among pathogenic mycobacteria, including Mycobacterium tuberculosis and Mycobacterium marinum, the ESAT-6 system 1 (ESX-1) secretion is crucial for host interaction. Secretion of protein substrates by the ESX-1 secretion system disrupts phagosomes, allowing mycobacteria cytoplasmic access during macrophage infections. Deletion or mutation of the ESX-1 system attenuates mycobacterial pathogens. Pathogenic mycobacteria respond to the presence or absence of the ESX-1 system in the cytoplasmic membrane by altering transcription. Under laboratory conditions, the EspM repressor and WhiB6 activator control transcription of specific ESX-1-responsive genes, including the ESX-1 substrate genes. However, deleting the espM or whiB6 gene does not phenocopy the deletion of the ESX-1 substrate genes during macrophage infection by M. marinum. In this study, we identified EspN, a critical transcription factor whose activity is masked by the EspM repressor under laboratory conditions. In the absence of EspM, EspN activates transcription of whiB6 and ESX-1 genes during both laboratory growth and macrophage infection. EspN is also independently required for M. marinum growth within and cytolysis of macrophages, similar to the ESX-1 genes, and for disease burden in a zebrafish larval model of infection. These findings suggest that EspN and EspM coordinate to counterbalance the regulation of the ESX-1 system and support mycobacterial pathogenesis.IMPORTANCEPathogenic mycobacteria, which are responsible for tuberculosis and other long-term diseases, use the ESX-1 system to transport proteins that control the host response to infection and promote bacterial survival. In this study, we identify an undescribed transcription factor that controls the expression of ESX-1 genes and is required for both macrophage and animal infection. However, this transcription factor is not the primary regulator of ESX-1 genes under standard laboratory conditions. These findings identify a critical transcription factor that likely controls expression of a major virulence pathway during infection, but whose effect is not detectable with standard laboratory strains and growth conditions.
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Affiliation(s)
- Kathleen R. Nicholson
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Rachel M. Cronin
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Rebecca J. Prest
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Aruna R. Menon
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Yuwei Yang
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Madeleine K. Jennisch
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew M. Champion
- Department of Biological Sciences, 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
| | - David M. Tobin
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Immunology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Patricia A. Champion
- Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
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8
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Jaisinghani N, Previti ML, Andrade J, Askenazi M, Ueberheide B, Seeliger JC. Proteomics from compartment-specific APEX2 labeling in Mycobacterium tuberculosis reveals Type VII secretion substrates in the cell wall. Cell Chem Biol 2024; 31:523-533.e4. [PMID: 37967559 PMCID: PMC11106752 DOI: 10.1016/j.chembiol.2023.10.013] [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: 03/29/2023] [Revised: 07/20/2023] [Accepted: 10/13/2023] [Indexed: 11/17/2023]
Abstract
The cell wall of mycobacteria plays a key role in interactions with the environment. 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. 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 although chemical labeling of live cells did not exclusively label surface proteins, protein tagging by the engineered peroxidase APEX2 within live Mycobacterium tuberculosis accurately identified the cytosolic and cell wall proteomes. Our data indicate that substrates of the virulence-associated Type VII ESX secretion system are exposed to the 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, NY 11794, USA
| | - Mary L Previti
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA
| | - Joshua Andrade
- Proteomics Laboratory, New York University Grossman School of Medicine, New York, NY 10016, USA
| | | | - Beatrix Ueberheide
- Proteomics Laboratory, New York University Grossman School of Medicine, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Jessica C Seeliger
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, NY 11794, USA.
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9
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Bates TA, Trank-Greene M, Nguyenla X, Anastas A, Gurmessa SK, Merutka IR, Dixon SD, Shumate A, Groncki AR, Parson MAH, Ingram JR, Barklis E, Burke JE, Shinde U, Ploegh HL, Tafesse FG. ESAT-6 undergoes self-association at phagosomal pH and an ESAT-6 specific nanobody restricts M. tuberculosis growth in macrophages. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.16.553641. [PMID: 37645775 PMCID: PMC10462100 DOI: 10.1101/2023.08.16.553641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is known to survive within macrophages by compromising the integrity of the phagosomal compartment in which it resides. This activity primarily relies on the ESX-1 secretion system, predominantly involving the protein duo ESAT-6 and CFP-10. CFP-10 likely acts as a chaperone, while ESAT-6 likely disrupts phagosomal membrane stability via a largely unknown mechanism. we employ a series of biochemical analyses, protein modeling techniques, and a novel ESAT-6-specific nanobody to gain insight into the ESAT-6's mode of action. First, we measure the binding kinetics of the tight 1:1 complex formed by ESAT-6 and CFP-10 at neutral pH. Subsequently, we demonstrate a rapid self-association of ESAT-6 into large complexes under acidic conditions, leading to the identification of a stable tetrameric ESAT-6 species. Using molecular dynamics simulations, we pinpoint the most probable interaction interface. Furthermore, we show that cytoplasmic expression of an anti-ESAT-6 nanobody blocks Mtb replication, thereby underlining the pivotal role of ESAT-6 in intracellular survival. Together, these data suggest that ESAT-6 acts by a pH dependent mechanism to establish two-way communication between the cytoplasm and the Mtb-containing phagosome.
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Affiliation(s)
- Timothy A Bates
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Mila Trank-Greene
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Xammy Nguyenla
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Aidan Anastas
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Sintayehu K Gurmessa
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Ilaria R Merutka
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Shandee D Dixon
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Anthony Shumate
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Abigail R Groncki
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - Matthew AH Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Jessica R Ingram
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, Canada
| | - Ujwal Shinde
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon, United States
| | - Hidde L Ploegh
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, United States
| | - Fikadu G Tafesse
- Department of Molecular Microbiology and Immunology, Oregon Health & Sciences University, Portland, Oregon, United States
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10
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayake NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. Cell Rep 2023; 42:113229. [PMID: 37815915 PMCID: PMC10842194 DOI: 10.1016/j.celrep.2023.113229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/16/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023] Open
Abstract
Bacterial ribonucleoprotein bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here, we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We find 111 BR-body-enriched proteins showing that BR-bodies are more complex than previously assumed. We identify five BR-body-enriched proteins that undergo RNA-dependent phase separation in vitro with a complex network of condensate mixing. We observe that some RNP condensates co-assemble with preferred directionality, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body-associated proteins have the capacity to dissolve the condensate. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Imalka W Rathnayaka-Mudiyanselage
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | | | - Ali Hatami
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - C Bruce Mousseau
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Jamuna Vaishnav
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Michael Collins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Hadi Yassine
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Aishwarya Ghosh
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yingxi Zhu
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Matthew M Champion
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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11
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Collars OA, Jones BS, Hu DD, Weaver SD, Sherman TA, Champion MM, Champion PA. An N-acetyltransferase required for ESAT-6 N-terminal acetylation and virulence in Mycobacterium marinum. mBio 2023; 14:e0098723. [PMID: 37772840 PMCID: PMC10653941 DOI: 10.1128/mbio.00987-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/09/2023] [Indexed: 09/30/2023] Open
Abstract
IMPORTANCE N-terminal acetylation is a protein modification that broadly impacts basic cellular function and disease in higher organisms. Although bacterial proteins are N-terminally acetylated, little is understood how N-terminal acetylation impacts bacterial physiology and pathogenesis. Mycobacterial pathogens cause acute and chronic disease in humans and in animals. Approximately 15% of mycobacterial proteins are N-terminally acetylated, but the responsible enzymes are largely unknown. We identified a conserved mycobacterial protein required for the N-terminal acetylation of 23 mycobacterial proteins including the EsxA virulence factor. Loss of this enzyme from M. marinum reduced macrophage killing and spread of M. marinum to new host cells. Defining the acetyltransferases responsible for the N-terminal protein acetylation of essential virulence factors could lead to new targets for therapeutics against mycobacteria.
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Affiliation(s)
- Owen A. Collars
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, Indiana, USA
| | - Bradley S. Jones
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, Indiana, USA
| | - Daniel D. Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Simon D. Weaver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Taylor A. Sherman
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Matthew M. Champion
- Eck Institute for Global Health, University of Note 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 Note Dame, Notre Dame, Indiana, USA
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12
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Bunduc CM, Ding Y, Kuijl C, Marlovits TC, Bitter W, Houben ENG. Reconstitution of a minimal ESX-5 type VII secretion system suggests a role for PPE proteins in the outer membrane transport of proteins. mSphere 2023; 8:e0040223. [PMID: 37747201 PMCID: PMC10597459 DOI: 10.1128/msphere.00402-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 09/26/2023] Open
Abstract
Mycobacteria utilize type VII secretion systems (T7SSs) to secrete proteins across their highly hydrophobic and diderm cell envelope. Pathogenic mycobacteria have up to five different T7SSs, called ESX-1 to ESX-5, which are crucial for growth and virulence. Here, we use a functionally reconstituted ESX-5 system in the avirulent species Mycobacterium smegmatis that lacks ESX-5, to define the role of each esx-5 gene in system functionality. By creating an array of gene deletions and assessing protein levels of components and membrane complex assembly, we observed that only the five components of the inner membrane complex are required for its assembly. However, in addition to these five core components, active secretion also depends on both the Esx and PE/PPE substrates. Tagging the PPE substrates followed by subcellular fractionation, surface labeling and membrane extraction showed that these proteins localize to the mycobacterial outer membrane. This indicates that they could play a role in secretion across this enigmatic outer barrier. These results provide the first full overview of the role of each esx-5 gene in T7SS functionality. IMPORTANCE Pathogenic mycobacteria, such as the notorious Mycobacterium tuberculosis, are highly successful as pathogens, in part due to their specific and diderm cell envelope, with a mycolic acid-containing outer membrane. The architecture of this highly impermeable membrane is little understood and the proteins that populate it even less so. To transport proteins across their cell envelope, mycobacteria employ a specialized transport pathway called type VII secretion. While recent studies have elucidated the type VII secretion membrane channel that mediates transport across the inner membrane, the identity of the outer membrane channel remains a black box. Here, we show evidence that specific substrates of the type VII pathway could form these channels. Elucidating the pathway and mechanism of protein secretion through the mycobacterial outer membrane will allow its exploitation for the development of novel mycobacterial therapeutics.
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Affiliation(s)
- C. M. Bunduc
- Molecular Microbiology Section, Amsterdam Institute for Life and Environment (A-Life), Vrije Universiteit, Amsterdam, The Netherlands
- Centre for Structural Systems Biology, Notkestraße, Hamburg, Germany
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Notkestraße, Hamburg, Germany
- German Electron Synchrotron Centre, Notkestraße, Hamburg, Germany
| | - Y. Ding
- Molecular Microbiology Section, Amsterdam Institute for Life and Environment (A-Life), Vrije Universiteit, Amsterdam, The Netherlands
| | - C. Kuijl
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Amsterdam, The Netherlands
| | - T. C. Marlovits
- Centre for Structural Systems Biology, Notkestraße, Hamburg, Germany
- Institute of Structural and Systems Biology, University Medical Center Hamburg-Eppendorf, Notkestraße, Hamburg, Germany
- German Electron Synchrotron Centre, Notkestraße, Hamburg, Germany
| | - W. Bitter
- Molecular Microbiology Section, Amsterdam Institute for Life and Environment (A-Life), Vrije Universiteit, Amsterdam, The Netherlands
- Department of Medical Microbiology and Infection Control, Amsterdam UMC, Amsterdam, The Netherlands
| | - E. N. G. Houben
- Molecular Microbiology Section, Amsterdam Institute for Life and Environment (A-Life), Vrije Universiteit, Amsterdam, The Netherlands
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13
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayak NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524314. [PMID: 36712072 PMCID: PMC9882336 DOI: 10.1101/2023.01.18.524314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial RNP bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We found 111 BR-body enriched proteins, including several RNA binding proteins, many of which are also recruited directly to in vitro reconstituted RNase E droplets, showing BR-bodies are more complex than previously assumed. While most BR-body enriched proteins that were tested cannot phase separate, we identified five that undergo RNA-dependent phase separation in vitro, showing other RNP condensates interface with BR-bodies. RNA degradosome protein clients are recruited more strongly to RNase E droplets than droplets of other RNP condensates, implying that client specificity is largely achieved through direct protein-protein interactions. We observe that some RNP condensates assemble with preferred directionally, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body associated proteins have the capacity to dissolve the condensate. Finally, we find that RNA dramatically stimulates the rate of RNase E phase separation in vitro, explaining the dissolution of BR-bodies after cellular mRNA depletion observed previously. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- V Nandana
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - I W Rathnayaka-Mudiyanselage
- Wayne State University, Department of Biological Sciences, Detroit, MI
- Wayne State University, Department of Chemistry, Detroit, MI
| | - N S Muthunayak
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Hatami
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - C B Mousseau
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | | | - J Vaishnav
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M Collins
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - A Gega
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | | | - H Yassine
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Ghosh
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - J S Biteen
- University of Michigan, Department of Chemistry, Ann Arbor, MI
| | - Y Zhu
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M M Champion
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | - W S Childers
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - J M Schrader
- Wayne State University, Department of Biological Sciences, Detroit, MI
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14
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Famelis N, Geibel S, van Tol D. Mycobacterial type VII secretion systems. Biol Chem 2023; 0:hsz-2022-0350. [PMID: 37276364 DOI: 10.1515/hsz-2022-0350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 05/22/2023] [Indexed: 06/07/2023]
Abstract
Mycobacteria, such as the pathogen M. tuberculosis, utilize up to five paralogous type VII secretion systems to transport proteins across their cell envelope. Since these proteins associate in pairs that depend on each other for transport to a different extent, the secretion pathway to the bacterial surface remained challenging to address. Structural characterization of the inner-membrane embedded secretion machineries along with recent advances on the substrates' co-dependencies for transport allow for the first time more detailed and testable models for secretion.
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Affiliation(s)
- Nikolaos Famelis
- Institute for Molecular Infection Biology, Julius Maximilian University of Würzburg, D-97080 Würzburg, Germany
| | - Sebastian Geibel
- Leiden Institute of Chemistry, Leiden University, NL-2333 CC Leiden, Netherlands
| | - Daan van Tol
- Leiden Institute of Chemistry, Leiden University, NL-2333 CC Leiden, Netherlands
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15
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Leddy O, White FM, Bryson BD. Immunopeptidomics reveals determinants of Mycobacterium tuberculosis antigen presentation on MHC class I. eLife 2023; 12:e84070. [PMID: 37073954 PMCID: PMC10159623 DOI: 10.7554/elife.84070] [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: 10/10/2022] [Accepted: 04/17/2023] [Indexed: 04/20/2023] Open
Abstract
CD8+ T cell recognition of Mycobacterium tuberculosis (Mtb)-specific peptides presented on major histocompatibility complex class I (MHC-I) contributes to immunity to tuberculosis (TB), but the principles that govern presentation of Mtb antigens on MHC-I are incompletely understood. In this study, mass spectrometry (MS) analysis of the MHC-I repertoire of Mtb-infected primary human macrophages reveals that substrates of Mtb's type VII secretion systems (T7SS) are overrepresented among Mtb-derived peptides presented on MHC-I. Quantitative, targeted MS shows that ESX-1 activity is required for presentation of Mtb peptides derived from both ESX-1 substrates and ESX-5 substrates on MHC-I, consistent with a model in which proteins secreted by multiple T7SSs access a cytosolic antigen processing pathway via ESX-1-mediated phagosome permeabilization. Chemical inhibition of proteasome activity, lysosomal acidification, or cysteine cathepsin activity did not block presentation of Mtb antigens on MHC-I, suggesting involvement of other proteolytic pathways or redundancy among multiple pathways. Our study identifies Mtb antigens presented on MHC-I that could serve as targets for TB vaccines, and reveals how the activity of multiple T7SSs interacts to contribute to presentation of Mtb antigens on MHC-I.
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Affiliation(s)
- Owen Leddy
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- Ragon Institute of Massachusetts General Hospital, Harvard, and MITCambridgeUnited States
- Koch Institute for Integrative Cancer ResearchCambridgeUnited States
| | - Forest M White
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- Koch Institute for Integrative Cancer ResearchCambridgeUnited States
- Center for Precision Cancer MedicineCambridgeUnited States
| | - Bryan D Bryson
- Department of Biological Engineering, Massachusetts Institute of TechnologyCambridgeUnited States
- Ragon Institute of Massachusetts General Hospital, Harvard, and MITCambridgeUnited States
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16
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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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17
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Collars OA, Jones BS, Hu DD, Weaver SD, Champion MM, Champion PA. An N-acetyltransferase required for EsxA N-terminal protein acetylation and virulence in Mycobacterium marinum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.14.532585. [PMID: 36993388 PMCID: PMC10055061 DOI: 10.1101/2023.03.14.532585] [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: 04/29/2023]
Abstract
N-terminal protein acetylation is a ubiquitous post-translational modification that broadly impacts diverse cellular processes in higher organisms. Bacterial proteins are also N-terminally acetylated, but the mechanisms and consequences of this modification in bacteria are poorly understood. We previously quantified widespread N-terminal protein acetylation in pathogenic mycobacteria (C. R. Thompson, M. M. Champion, and P.A. Champion, J Proteome Res 17(9): 3246-3258, 2018, https:// doi: 10.1021/acs.jproteome.8b00373). The major virulence factor EsxA (ESAT-6, Early secreted antigen, 6kDa) was one of the first N-terminally acetylated proteins identified in bacteria. EsxA is conserved in mycobacterial pathogens, including Mycobacterium tuberculosis and Mycobacterium marinum, a non-tubercular mycobacterial species that causes tuberculosis-like disease in ectotherms. However, enzyme responsible for EsxA N-terminal acetylation has been elusive. Here, we used genetics, molecular biology, and mass-spectroscopy based proteomics to demonstrate that MMAR_1839 (renamed Emp1, ESX-1 modifying protein, 1) is the putative N-acetyl transferase (NAT) solely responsible for EsxA acetylation in Mycobacterium marinum. We demonstrated that ERD_3144, the orthologous gene in M. tuberculosis Erdman, is functionally equivalent to Emp1. We identified at least 22 additional proteins that require Emp1 for acetylation, demonstrating that this putative NAT is not dedicated to EsxA. Finally, we showed that loss of emp1 resulted in a significant reduction in the ability of M. marinum to cause macrophage cytolysis. Collectively, this study identified a NAT required for N-terminal acetylation in Mycobacterium and provided insight into the requirement of N-terminal acetylation of EsxA and other proteins in mycobacterial virulence in the macrophage.
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Affiliation(s)
- Owen A. Collars
- Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, USA
| | - Bradley S. Jones
- Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, USA
| | - Daniel D. Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, USA
| | - Simon D. Weaver
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, USA
| | - Matthew M. Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, USA
| | - Patricia A. Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, USA
- Eck Institute for Global Health, University of Note Dame, Notre Dame, USA
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18
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Mousseau CB, Pierre CA, Hu DD, Champion MM. Miniprep assisted proteomics (MAP) for rapid proteomics sample preparation. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2023; 15:916-924. [PMID: 36373982 PMCID: PMC9933840 DOI: 10.1039/d2ay01549h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/28/2022] [Indexed: 06/14/2023]
Abstract
Complete enzymatic digestion of proteins for bottom-up proteomics is substantially improved by use of detergents for denaturation and solubilization. Detergents however, are incompatible with many proteases and highly detrimental to LC-MS/MS. Recently; filter-based methods have seen wide use due to their capacity to remove detergents and harmful reagents prior to digestion and mass spectrometric analysis. We hypothesized that non-specific protein binding to negatively charged silica-based filters would be enhanced by addition of lyotropic salts, similar to DNA purification. We sought to exploit these interactions and investigate if low-cost DNA purification spin-filters, 'Minipreps,' efficiently and reproducibly bind proteins for digestion and LC-MS/MS analysis. We propose a new method, Miniprep Assisted Proteomics (MAP), for sample preparation. We demonstrate binding capacity, performance, recovery and identification rates for proteins and whole-cell lysates using MAP. MAP recovered equivalent or greater protein yields from 0.5-50 μg analyses benchmarked against commercial trapping preparations. Nano UHPLC-MS/MS proteome profiling of lysates of Escherichia coli had 99.3% overlap vs. existing approaches and reproducibility of replicate minipreps was 98.8% at the 1% FDR protein level. Label Free Quantitative proteomics was performed and 91.2% of quantified proteins had a %CV <20% (2044/2241). Miniprep Assisted Proteomics can be performed in minutes, shows low variability, high recovery and proteome depth. This suggests a significant role for adventitious binding in developing new proteomics sample preparation techniques. MAP represents an efficient, ultra-low-cost alternative for sample preparation in a commercially obtainable device that costs ∼$0.50 (USD) per miniprep.
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Affiliation(s)
- C Bruce Mousseau
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA.
| | - Camille A Pierre
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA.
| | - Daniel D Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA.
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556, USA.
- Berthiaume Institute for Precision Health, University of Notre Dame, Notre Dame, IN 46556, USA
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19
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The EspN transcription factor is an infection-dependent regulator of the ESX-1 system in M. marinum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528779. [PMID: 36824794 PMCID: PMC9948972 DOI: 10.1101/2023.02.15.528779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Bacterial pathogens use protein secretion systems to translocate virulence factors into the host and to control bacterial gene expression. The ESX-1 (ESAT-6 system 1) secretion system facilitates disruption of the macrophage phagosome during infection, enabling access to the cytoplasm, and regulates widespread gene expression in the mycobacterial cell. The transcription factors contributing to the ESX-1 transcriptional network during mycobacterial infection are not known. We showed that the EspM and WhiB6 transcription factors regulate the ESX-1 transcriptional network in vitro but are dispensable for macrophage infection by Mycobacterium marinum . In this study, we used our understanding of the ESX-1 system to identify EspN, a critical transcription factor that controls expression of the ESX-1 genes during infection, but whose effect is not detectable under standard laboratory growth conditions. Under laboratory conditions, EspN activity is masked by the EspM repressor. In the absence of EspM, we found that EspN is required for ESX-1 function because it activates expression of the whiB6 transcription factor gene, and specific ESX-1 substrate and secretory component genes. Unlike the other transcription factors that regulate ESX-1, EspN is required for M. marinum growth within and cytolysis of macrophages, and for disease burden in a zebrafish larval model of infection. These findings demonstrate that EspN is an infection-dependent regulator of the ESX-1 transcriptional network, which is essential for mycobacterial pathogenesis. Moreover, our findings suggest that ESX-1 expression is controlled by a genetic switch that responds to host specific signals. Importance Pathogenic mycobacteria cause acute and long-term diseases, including human tuberculosis. The ESX-1 system transports proteins that control the host response to infection and promotes bacterial survival. Although ESX-1 transports proteins, it also controls gene expression in the bacteria. In this study, we identify an undescribed transcription factor that controls the expression of ESX-1 genes, and is required for both macrophage and animal infection. However, this transcription factor is not the primary regulator of ESX-1 genes under standard laboratory conditions. These findings identify a critical transcription factor that controls expression of a major virulence pathway during infection, but whose effect is not detectable with standard laboratory strains and growth conditions.
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20
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Weaver S, DeRosa CM, Schultz SR, Champion MM. PrIntMap-R: An Online Application for Intraprotein Intensity and Peptide Visualization from Bottom-Up Proteomics. J Proteome Res 2023; 22:432-441. [PMID: 36652611 PMCID: PMC9904286 DOI: 10.1021/acs.jproteome.2c00606] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Bottom-up proteomics (BUP) produces rich data, but visualization and analysis are time-consuming and often require programming skills. Many tools analyze these data at the proteome-level, but fewer options exist for individual proteins. Sequence coverage maps are common, but do not proportion peptide intensity. Abundance-based visualization of sequence coverage facilitates detection of protein isoforms, domains, potential truncation sites, peptide "hot-spots", and localization of post-translational modifications (PTMs). Redundant stacked-sequence coverage is an important tool in designing hydrogen-deuterium exchange (HDX) experiments. Visualization tools often lack graphical and tabular-export of processed data which complicates publication of results. Quantitative peptide abundance across amino acid sequences is an essential and missing tool in proteomics toolkits. Here we created PrIntMap-R, an online application that only requires peptide files from a database search and FASTA protein sequences. PrIntMap-R produces a variety of plots for quantitative visualization of coverage; annotation of specific sequences, PTM's, and comparisons of one or many samples overlaid with calculated fold-change or several intensity metrics. We show use-cases including protein phosphorylation, identification of glycosylation, and the optimization of digestion conditions for HDX experiments. PrIntMap-R is freely available, open source, and can run online with no installation, or locally by downloading source code from GitHub.
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Affiliation(s)
- Simon
D. Weaver
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States,Integrated
Biomedical Sciences Graduate Program, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Christine M. DeRosa
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Sadie R. Schultz
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States
| | - Matthew M. Champion
- Department
of Chemistry and Biochemistry, University
of Notre Dame, Notre
Dame, Indiana 46556, United States,Integrated
Biomedical Sciences Graduate Program, University
of Notre Dame, Notre
Dame, Indiana 46556, United States,
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21
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The ESX-1 Substrate PPE68 Has a Key Function in ESX-1-Mediated Secretion in Mycobacterium marinum. mBio 2022; 13:e0281922. [PMID: 36409073 PMCID: PMC9765416 DOI: 10.1128/mbio.02819-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Mycobacteria use specialized type VII secretion systems (T7SSs) to secrete proteins across their diderm cell envelope. One of the T7SS subtypes, named ESX-1, is a major virulence determinant in pathogenic species such as Mycobacterium tuberculosis and the fish pathogen Mycobacterium marinum. ESX-1 secretes a variety of substrates, called Esx, PE, PPE, and Esp proteins, at least some of which are folded heterodimers. Investigation into the functions of these substrates is problematic, because of the intricate network of codependent secretion between several ESX-1 substrates. Here, we describe the ESX-1 substrate PPE68 as essential for secretion of the highly immunogenic substrates EsxA and EspE via the ESX-1 system in M. marinum. While secreted PPE68 is processed on the cell surface, the majority of cell-associated PPE68 of M. marinum and M. tuberculosis is present in a cytosolic complex with its PE partner and the EspG1 chaperone. Interfering with the binding of EspG1 to PPE68 blocked its export and the secretion of EsxA and EspE. In contrast, esxA was not required for the secretion of PPE68, revealing a hierarchy in codependent secretion. Remarkably, the final 10 residues of PPE68, a negatively charged domain, seem essential for EspE secretion, but not for the secretion of EsxA and of PPE68 itself. This indicates that distinctive domains of PPE68 are involved in secretion of the different ESX-1 substrates. Based on these findings, we propose a mechanistic model for the central role of PPE68 in ESX-1-mediated secretion and substrate codependence. IMPORTANCE Pathogenic mycobacteria, such Mycobacterium tuberculosis and Mycobacterium marinum, use a type VII secretion system (T7SS) subtype, called ESX-1, to mediate intracellular survival via phagosomal rupture and subsequent translocation of the mycobacterium to the host cytosol. Identifying the ESX-1 substrate that is responsible for this process is problematic because of the intricate network of codependent secretion between ESX-1 substrates. Here, we show the central role of the ESX-1 substrate PPE68 for the secretion of ESX-1 substrates in Mycobacterium marinum. Unravelling the mechanism of codependent secretion will aid the functional understanding of T7SSs and will allow the analysis of the individual roles of ESX-1 substrates in the virulence caused by the significant human pathogen Mycobacterium tuberculosis.
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22
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Gijsbers A, Eymery M, Gao Y, Menart I, Vinciauskaite V, Siliqi D, Peters PJ, McCarthy A, Ravelli RBG. The crystal structure of the EspB-EspK virulence factor-chaperone complex suggests an additional type VII secretion mechanism in Mycobacterium tuberculosis. J Biol Chem 2022; 299:102761. [PMID: 36463964 PMCID: PMC9811218 DOI: 10.1016/j.jbc.2022.102761] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
Pathogenic species from the Mycobacterium genus are responsible for a number of adverse health conditions in humans and animals that threaten health security and the economy worldwide. Mycobacteria have up to five specialized secretion systems (ESX-1 to ESX-5) that transport virulence factors across their complex cell envelope to facilitate manipulation of their environment. In pathogenic species, these virulence factors influence the immune system's response and are responsible for membrane disruption and contributing to cell death. While structural details of these secretion systems have been recently described, gaps still remain in the structural understanding of the secretion mechanisms of most substrates. Here, we describe the crystal structure of Mycobacterium tuberculosis ESX-1 secretion-associated substrate EspB bound to its chaperone EspK. We found that EspB interacts with the C-terminal domain of EspK through its helical tip. Furthermore, cryogenic electron microscopy, size exclusion chromatography analysis, and small-angle X-ray scattering experiments show that EspK keeps EspB in its secretion-competent monomeric form and prevents its oligomerization. The structure presented in this study suggests an additional secretion mechanism in ESX-1, analogous to the chaperoning of proline-glutamate (PE)-proline-proline-glutamate (PPE) proteins by EspG, where EspK facilitates the secretion of EspB in Mycobacterium species.
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Affiliation(s)
- Abril Gijsbers
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | | | - Ye Gao
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Isabella Menart
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Vanesa Vinciauskaite
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | - Dritan Siliqi
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Bari, Italy
| | - Peter J Peters
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands
| | | | - Raimond B G Ravelli
- Division of Nanoscopy, Maastricht Multimodal Molecular Imaging Institute (M4i), Maastricht University, Maastricht, the Netherlands.
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23
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Saelens JW, Sweeney MI, Viswanathan G, Xet-Mull AM, Jurcic Smith KL, Sisk DM, Hu DD, Cronin RM, Hughes EJ, Brewer WJ, Coers J, Champion MM, Champion PA, Lowe CB, Smith CM, Lee S, Stout JE, Tobin DM. An ancestral mycobacterial effector promotes dissemination of infection. Cell 2022; 185:4507-4525.e18. [PMID: 36356582 PMCID: PMC9691622 DOI: 10.1016/j.cell.2022.10.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 08/27/2022] [Accepted: 10/16/2022] [Indexed: 11/11/2022]
Abstract
The human pathogen Mycobacterium tuberculosis typically causes lung disease but can also disseminate to other tissues. We identified a M. tuberculosis (Mtb) outbreak presenting with unusually high rates of extrapulmonary dissemination and bone disease. We found that the causal strain carried an ancestral full-length version of the type VII-secreted effector EsxM rather than the truncated version present in other modern Mtb lineages. The ancestral EsxM variant exacerbated dissemination through enhancement of macrophage motility, increased egress of macrophages from established granulomas, and alterations in macrophage actin dynamics. Reconstitution of the ancestral version of EsxM in an attenuated modern strain of Mtb altered the migratory mode of infected macrophages, enhancing their motility. In a zebrafish model, full-length EsxM promoted bone disease. The presence of a derived nonsense variant in EsxM throughout the major Mtb lineages 2, 3, and 4 is consistent with a role for EsxM in regulating the extent of dissemination.
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Affiliation(s)
- Joseph W Saelens
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mollie I Sweeney
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Gopinath Viswanathan
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Ana María Xet-Mull
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kristen L Jurcic Smith
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Dana M Sisk
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Daniel D Hu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Rachel M Cronin
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Erika J Hughes
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - W Jared Brewer
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Matthew M Champion
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA; Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Patricia A Champion
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA; Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Craig B Lowe
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Clare M Smith
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Sunhee Lee
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Jason E Stout
- Department of Medicine, Duke University School of Medicine, Durham, NC 27710, USA; Division of Infectious Diseases and International Health, Duke University School of Medicine, Durham, NC 27710, USA.
| | - David M Tobin
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA; Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA.
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24
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Gonzalez LE, Szalwinski LJ, Sams TC, Dziekonski ET, Cooks RG. Metabolomic and Lipidomic Profiling of Bacillus Using Two-Dimensional Tandem Mass Spectrometry. Anal Chem 2022; 94:16838-16846. [DOI: 10.1021/acs.analchem.2c03961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- L. Edwin Gonzalez
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Lucas J. Szalwinski
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Thomas C. Sams
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Eric T. Dziekonski
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - R. Graham Cooks
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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