1
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Paul Ikujuni A, Dhar R, Cordova A, Bowman AM, Noga S, Slusky JSG. Discovery and Characterization of Two Folded Intermediates for Outer Membrane Protein TolC Biogenesis. J Mol Biol 2024:168652. [PMID: 38871177 DOI: 10.1016/j.jmb.2024.168652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 05/12/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024]
Abstract
TolC is the outer membrane protein responsible for antibiotic efflux in E. coli. Compared to other outer membrane proteins it has an unusual fold and has been shown to fold independently of commonly used periplasmic chaperones, SurA and Skp. Here we find that the assembly of TolC involves the formation of two folded intermediates using circular dichroism, gel electrophoresis, site-specific disulfide bond formation and radioactive labeling. First the TolC monomer folds, and then TolC assembles into a trimer both in detergent-free buffer and in the presence of detergent micelles. We find that a TolC trimer also forms in the periplasm and is present in the periplasm before it inserts in the outer membrane. The monomeric and trimeric folding intermediates may be used in the future to develop a new approach to antibiotic efflux pump inhibition by targeting the assembly pathway of TolC.
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Affiliation(s)
- Ayotunde Paul Ikujuni
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045
| | - Rik Dhar
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045
| | - Andres Cordova
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045
| | - Alexander M Bowman
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045
| | - Sarah Noga
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045
| | - Joanna S G Slusky
- Department of Molecular Biosciences, The University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045; Computational Biology Program, The University of Kansas, 2030 Becker Dr., Lawrence, KS 66045-7534.
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2
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Tang D, Gueto-Tettay C, Hjortswang E, Ströbaek J, Ekström S, Happonen L, Malmström L, Malmström J. Multimodal Mass Spectrometry Identifies a Conserved Protective Epitope in S. pyogenes Streptolysin O. Anal Chem 2024; 96:9060-9068. [PMID: 38701337 PMCID: PMC11154737 DOI: 10.1021/acs.analchem.4c00596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 04/16/2024] [Accepted: 04/24/2024] [Indexed: 05/05/2024]
Abstract
An important element of antibody-guided vaccine design is the use of neutralizing or opsonic monoclonal antibodies to define protective epitopes in their native three-dimensional conformation. Here, we demonstrate a multimodal mass spectrometry-based strategy for in-depth characterization of antigen-antibody complexes to enable the identification of protective epitopes using the cytolytic exotoxin Streptolysin O (SLO) from Streptococcus pyogenes as a showcase. We first discovered a monoclonal antibody with an undisclosed sequence capable of neutralizing SLO-mediated cytolysis. The amino acid sequence of both the antibody light and the heavy chain was determined using mass-spectrometry-based de novo sequencing, followed by chemical cross-linking mass spectrometry to generate distance constraints between the antibody fragment antigen-binding region and SLO. Subsequent integrative computational modeling revealed a discontinuous epitope located in domain 3 of SLO that was experimentally validated by hydrogen-deuterium exchange mass spectrometry and reverse engineering of the targeted epitope. The results show that the antibody inhibits SLO-mediated cytolysis by binding to a discontinuous epitope in domain 3, likely preventing oligomerization and subsequent secondary structure transitions critical for pore-formation. The epitope is highly conserved across >98% of the characterized S. pyogenes isolates, making it an attractive target for antibody-based therapy and vaccine design against severe streptococcal infections.
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Affiliation(s)
- Di Tang
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Carlos Gueto-Tettay
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Elisabeth Hjortswang
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Joel Ströbaek
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Simon Ekström
- SciLifeLab,
Integrated Structural Biology Platform, Structural Proteomics Unit
Sweden, Lund University, Klinikgatan 32, 222
42 Lund, Sweden
| | - Lotta Happonen
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Lars Malmström
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
| | - Johan Malmström
- Division
of Infection Medicine, Department of Clinical Sciences, Faculty of
Medicine, Lund University, Klinikgatan 32, 222 42 Lund, Sweden
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3
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Kang R, Kim K, Jung Y, Choi SH, Lee C, Im GH, Shin M, Ryu K, Choi S, Yang E, Shin W, Lee S, Lee S, Papadopoulos Z, Ahn JH, Koh GY, Kipnis J, Kang H, Kim H, Cho WK, Park S, Kim SG, Kim E. Loss of Katnal2 leads to ependymal ciliary hyperfunction and autism-related phenotypes in mice. PLoS Biol 2024; 22:e3002596. [PMID: 38718086 PMCID: PMC11104772 DOI: 10.1371/journal.pbio.3002596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/20/2024] [Accepted: 03/21/2024] [Indexed: 05/22/2024] Open
Abstract
Autism spectrum disorders (ASD) frequently accompany macrocephaly, which often involves hydrocephalic enlargement of brain ventricles. Katnal2 is a microtubule-regulatory protein strongly linked to ASD, but it remains unclear whether Katnal2 knockout (KO) in mice leads to microtubule- and ASD-related molecular, synaptic, brain, and behavioral phenotypes. We found that Katnal2-KO mice display ASD-like social communication deficits and age-dependent progressive ventricular enlargements. The latter involves increased length and beating frequency of motile cilia on ependymal cells lining ventricles. Katnal2-KO hippocampal neurons surrounded by enlarged lateral ventricles show progressive synaptic deficits that correlate with ASD-like transcriptomic changes involving synaptic gene down-regulation. Importantly, early postnatal Katnal2 re-expression prevents ciliary, ventricular, and behavioral phenotypes in Katnal2-KO adults, suggesting a causal relationship and a potential treatment. Therefore, Katnal2 negatively regulates ependymal ciliary function and its deletion in mice leads to ependymal ciliary hyperfunction and hydrocephalus accompanying ASD-related behavioral, synaptic, and transcriptomic changes.
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Affiliation(s)
- Ryeonghwa Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Kyungdeok Kim
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Yewon Jung
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Sang-Han Choi
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Chanhee Lee
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea
| | - Geun Ho Im
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea
| | - Miram Shin
- Department of Biological Sciences, Sookmyung Women’s University, Seoul, Korea
| | - Kwangmin Ryu
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Subin Choi
- Department of Biological Sciences, Sookmyung Women’s University, Seoul, Korea
| | - Esther Yang
- Department of Anatomy, Biomedical Sciences, College of Medicine, Korea University, Seoul, Korea
| | - Wangyong Shin
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Seungjoon Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Suho Lee
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
| | - Zachary Papadopoulos
- Neuroscience Graduate Program, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Ji Hoon Ahn
- Center for Vascular Research, Institute for Basic Science (IBS), Daejeon, Korea
| | - Gou Young Koh
- Center for Vascular Research, Institute for Basic Science (IBS), Daejeon, Korea
| | - Jonathan Kipnis
- Neuroscience Graduate Program, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Brain Immunology and Glia (BIG) Center, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Pathology and Immunology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Hyojin Kang
- Division of National Supercomputing, Korea Institute of Science and Technology Information (KISTI), Daejeon, Korea
| | - Hyun Kim
- Department of Anatomy, Biomedical Sciences, College of Medicine, Korea University, Seoul, Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Soochul Park
- Department of Biological Sciences, Sookmyung Women’s University, Seoul, Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
- Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon, Korea
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4
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Aziz UBA, Saoud A, Bermudez M, Mieth M, Atef A, Rudolf T, Arkona C, Trenkner T, Böttcher C, Ludwig K, Hoelzemer A, Hocke AC, Wolber G, Rademann J. Targeted small molecule inhibitors blocking the cytolytic effects of pneumolysin and homologous toxins. Nat Commun 2024; 15:3537. [PMID: 38670939 PMCID: PMC11053136 DOI: 10.1038/s41467-024-47741-3] [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: 07/14/2023] [Accepted: 04/08/2024] [Indexed: 04/28/2024] Open
Abstract
Pneumolysin (PLY) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pneumoniae, the main cause for bacterial pneumonia. Liberation of PLY during infection leads to compromised immune system and cytolytic cell death. Here, we report discovery, development, and validation of targeted small molecule inhibitors of PLY (pore-blockers, PB). PB-1 is a virtual screening hit inhibiting PLY-mediated hemolysis. Structural optimization provides PB-2 with improved efficacy. Cryo-electron tomography reveals that PB-2 blocks PLY-binding to cholesterol-containing membranes and subsequent pore formation. Scaffold-hopping delivers PB-3 with superior chemical stability and solubility. PB-3, formed in a protein-templated reaction, binds to Cys428 adjacent to the cholesterol recognition domain of PLY with a KD of 256 nM and a residence time of 2000 s. It acts as anti-virulence factor preventing human lung epithelial cells from PLY-mediated cytolysis and cell death during infection with Streptococcus pneumoniae and is active against the homologous Cys-containing CDC perfringolysin (PFO) as well.
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Affiliation(s)
- Umer Bin Abdul Aziz
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Ali Saoud
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Marcel Bermudez
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstr. 48, 48149, Münster, Germany
| | - Maren Mieth
- Department of Infectious Diseases, Respiratory Medicine, and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Amira Atef
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
- Department of Medicinal Chemistry, Faculty of Pharmacy, Assuit University, Assiut, 71526, Egypt
| | - Thomas Rudolf
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Christoph Arkona
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Timo Trenkner
- Leibniz Institute of Virology, Hamburg, 20251, Germany
| | - Christoph Böttcher
- Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy (FZEM), Freie Universität Berlin, Fabeckstraße 36A, 14195, Berlin, Germany
| | - Kai Ludwig
- Institute of Chemistry and Biochemistry, Research Center of Electron Microscopy (FZEM), Freie Universität Berlin, Fabeckstraße 36A, 14195, Berlin, Germany
| | - Angelique Hoelzemer
- Leibniz Institute of Virology, Hamburg, 20251, Germany
- First Department of Medicine, University Medical Center Hamburg-Eppendorf (UKE), 20251, Hamburg, Germany
| | - Andreas C Hocke
- Department of Infectious Diseases, Respiratory Medicine, and Critical Care, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gerhard Wolber
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany
| | - Jörg Rademann
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2+4, 14195, Berlin, Germany.
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5
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Zhu C, Xu S, Jiang R, Yu Y, Bian J, Zou Z. The gasdermin family: emerging therapeutic targets in diseases. Signal Transduct Target Ther 2024; 9:87. [PMID: 38584157 PMCID: PMC10999458 DOI: 10.1038/s41392-024-01801-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/03/2024] [Accepted: 03/05/2024] [Indexed: 04/09/2024] Open
Abstract
The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.
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Affiliation(s)
- Chenglong Zhu
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, 200433, China
- School of Anesthesiology, Naval Medical University, Shanghai, 200433, China
| | - Sheng Xu
- National Key Laboratory of Immunity & Inflammation, Naval Medical University, Shanghai, 200433, China
| | - Ruoyu Jiang
- School of Anesthesiology, Naval Medical University, Shanghai, 200433, China
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Naval Medical University, Shanghai, 200433, China
| | - Yizhi Yu
- National Key Laboratory of Immunity & Inflammation, Naval Medical University, Shanghai, 200433, China.
| | - Jinjun Bian
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, 200433, China.
| | - Zui Zou
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, 200433, China.
- School of Anesthesiology, Naval Medical University, Shanghai, 200433, China.
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6
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Johnson AG, Mayer ML, Schaefer SL, McNamara-Bordewick NK, Hummer G, Kranzusch PJ. Structure and assembly of a bacterial gasdermin pore. Nature 2024; 628:657-663. [PMID: 38509367 DOI: 10.1038/s41586-024-07216-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 02/20/2024] [Indexed: 03/22/2024]
Abstract
In response to pathogen infection, gasdermin (GSDM) proteins form membrane pores that induce a host cell death process called pyroptosis1-3. Studies of human and mouse GSDM pores have revealed the functions and architectures of assemblies comprising 24 to 33 protomers4-9, but the mechanism and evolutionary origin of membrane targeting and GSDM pore formation remain unknown. Here we determine a structure of a bacterial GSDM (bGSDM) pore and define a conserved mechanism of pore assembly. Engineering a panel of bGSDMs for site-specific proteolytic activation, we demonstrate that diverse bGSDMs form distinct pore sizes that range from smaller mammalian-like assemblies to exceptionally large pores containing more than 50 protomers. We determine a cryo-electron microscopy structure of a Vitiosangium bGSDM in an active 'slinky'-like oligomeric conformation and analyse bGSDM pores in a native lipid environment to create an atomic-level model of a full 52-mer bGSDM pore. Combining our structural analysis with molecular dynamics simulations and cellular assays, our results support a stepwise model of GSDM pore assembly and suggest that a covalently bound palmitoyl can leave a hydrophobic sheath and insert into the membrane before formation of the membrane-spanning β-strand regions. These results reveal the diversity of GSDM pores found in nature and explain the function of an ancient post-translational modification in enabling programmed host cell death.
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Affiliation(s)
- Alex G Johnson
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA.
| | - Megan L Mayer
- Harvard Center for Cryo-Electron Microscopy, Harvard Medical School, Boston, MA, USA
| | - Stefan L Schaefer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Philip J Kranzusch
- Department of Microbiology, Harvard Medical School, Boston, MA, USA.
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA.
- Parker Institute for Cancer Immunotherapy at Dana-Farber Cancer Institute, Boston, MA, USA.
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7
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Santra S, Nayak I, Paladhi A, Das D, Banerjee A. Estimates of differential toxin expression governing heterogeneous intracellular lifespans of Streptococcus pneumoniae. J Cell Sci 2024; 137:jcs260891. [PMID: 38411297 DOI: 10.1242/jcs.260891] [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: 12/14/2022] [Accepted: 01/10/2024] [Indexed: 02/28/2024] Open
Abstract
Following invasion of the host cell, pore-forming toxins secreted by pathogens compromise vacuole integrity and expose the microbe to diverse intracellular defence mechanisms. However, the quantitative correlation between toxin expression levels and consequent pore dynamics, fostering the intracellular life of pathogens, remains largely unexplored. In this study, using Streptococcus pneumoniae and its secreted pore-forming toxin pneumolysin (Ply) as a model system, we explored various facets of host-pathogen interactions in the host cytosol. Using time-lapse fluorescence imaging, we monitored pore formation dynamics and lifespans of different pneumococcal subpopulations inside host cells. Based on experimental histograms of various event timescales such as pore formation time, vacuolar death or cytosolic escape time and total degradation time, we developed a mathematical model based on first-passage processes that could correlate the event timescales to intravacuolar toxin accumulation. This allowed us to estimate Ply production rate, burst size and threshold Ply quantities that trigger these outcomes. Collectively, we present a general method that illustrates a correlation between toxin expression levels and pore dynamics, dictating intracellular lifespans of pathogens.
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Affiliation(s)
- Shweta Santra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Indrani Nayak
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Ankush Paladhi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Dibyendu Das
- Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Anirban Banerjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
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8
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Fusco F, Pires MC, Lopes APY, Alves VDS, Gonçalves VM. Influence of the mRNA initial region on protein production: a case study using recombinant detoxified pneumolysin as a model. Front Bioeng Biotechnol 2024; 11:1304965. [PMID: 38260740 PMCID: PMC10800503 DOI: 10.3389/fbioe.2023.1304965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 12/12/2023] [Indexed: 01/24/2024] Open
Abstract
Recombinant proteins are of great importance in modern society, mostly as biopharmaceutical products. However, challenging and complex processes with low production yield are major drawbacks. Normally, the optimization to overcome these obstacles is focused on bioreactor and purification processes, and the biomolecular aspects are neglected, seen as less important. In this work, we present how the 5' mRNA secondary structure region can be relevant for translation and, therefore, protein production. For this, Escherichia coli BL21(DE3) clones, producing recombinant detoxified pneumolysin (PdT) with and without the N-terminal His-tag, were cultivated in 10-L bioreactors. Another version of the pdt gene (version 2) with synonymous changes in the 5'-end nucleotide sequence was also obtained. Protein production, plasmid stability, carbon sources, and acetic acid were quantified during the cultures. Furthermore, in silico mRNA analyses were performed using TIsigner and RNAfold. The results showed that the His-tag presence at the N-terminus generated a minimum 1.5-fold increase in target protein synthesis, which was explained by the in silico mRNA analyses that returned an mRNA secondary structure easier to translate and, therefore, higher protein production than without the His-tag. The pdt gene version 2 showed lower 5' mRNA opening energy than version 1, allowing higher PdT production even without a tag. This work reveals that simple mRNA analyses during heterologous gene design and production steps can help reach high-recombinant protein titers in a shorter time than using only traditional bioprocess optimization strategies.
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Affiliation(s)
- Filipe Fusco
- Laboratory of Vaccine Development, Butantan Institute, Sao Paulo, Brazil
- Interunits Graduate Program in Biotechnology, University of Sao Paulo, Sao Paulo, Brazil
| | - Manuella Cazelato Pires
- Laboratory of Vaccine Development, Butantan Institute, Sao Paulo, Brazil
- Interunits Graduate Program in Biotechnology, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Vítor dos Santos Alves
- Laboratory of Vaccine Development, Butantan Institute, Sao Paulo, Brazil
- Interunits Graduate Program in Biotechnology, University of Sao Paulo, Sao Paulo, Brazil
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9
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Bazant J, Ott B, Hudel M, Hain T, Lucas R, Mraheil MA. Impact of Endogenous Pneumococcal Hydrogen Peroxide on the Activity and Release of Pneumolysin. Toxins (Basel) 2023; 15:593. [PMID: 37888624 PMCID: PMC10611280 DOI: 10.3390/toxins15100593] [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: 08/10/2023] [Revised: 09/21/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
Streptococcus pneumoniae is the leading cause of community-acquired pneumonia. The pore-forming cholesterol-dependent cytolysin (CDC) pneumolysin (PLY) and the physiological metabolite hydrogen peroxide (H2O2) can greatly increase the virulence of pneumococci. Although most studies have focused on the contribution of both virulence factors to the course of pneumococcal infection, it is unknown whether or how H2O2 can affect PLY activity. Of note, S. pneumoniae exploits endogenous H2O2 as an intracellular signalling molecule to modulate the activity of several proteins. Here, we demonstrate that H2O2 negatively affects the haemolytic activity of PLY in a concentration-dependent manner. Prevention of cysteine-dependent sulfenylation upon substitution of the unique and highly conserved cysteine residue to serine in PLY significantly reduces the toxin's susceptibility to H2O2 treatment and completely abolishes the ability of DTT to activate PLY. We also detect a clear gradual correlation between endogenous H2O2 generation and PLY release, with decreased H2O2 production causing a decline in the release of PLY. Comparative transcriptome sequencing analysis of the wild-type S. pneumoniae strain and three mutants impaired in H2O2 production indicates enhanced expression of several genes involved in peptidoglycan (PG) synthesis and in the production of choline-binding proteins (CPBs). One explanation for the impact of H2O2 on PLY release is the observed upregulation of the PG bridge formation alanyltransferases MurM and MurN, which evidentially negatively affect the PLY release. Our findings shed light on the significance of endogenous pneumococcal H2O2 in controlling PLY activity and release.
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Affiliation(s)
- Jasmin Bazant
- Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany; (J.B.); (B.O.); (M.H.); (T.H.)
| | - Benjamin Ott
- Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany; (J.B.); (B.O.); (M.H.); (T.H.)
| | - Martina Hudel
- Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany; (J.B.); (B.O.); (M.H.); (T.H.)
| | - Torsten Hain
- Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany; (J.B.); (B.O.); (M.H.); (T.H.)
| | - Rudolf Lucas
- Vascular Biology Center, Department of Pharmacology and Toxicology and Division of Pulmonary Critical Care Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA;
| | - Mobarak Abu Mraheil
- Institute of Medical Microbiology, German Center for Infection Research, Partner Site Giessen-Marburg-Langen, Justus-Liebig University Giessen, Schubertstrasse 81, 35392 Giessen, Germany; (J.B.); (B.O.); (M.H.); (T.H.)
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10
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Degen M, Santos JC, Pluhackova K, Cebrero G, Ramos S, Jankevicius G, Hartenian E, Guillerm U, Mari SA, Kohl B, Müller DJ, Schanda P, Maier T, Perez C, Sieben C, Broz P, Hiller S. Structural basis of NINJ1-mediated plasma membrane rupture in cell death. Nature 2023; 618:1065-1071. [PMID: 37198476 PMCID: PMC10307626 DOI: 10.1038/s41586-023-05991-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 03/21/2023] [Indexed: 05/19/2023]
Abstract
Eukaryotic cells can undergo different forms of programmed cell death, many of which culminate in plasma membrane rupture as the defining terminal event1-7. Plasma membrane rupture was long thought to be driven by osmotic pressure, but it has recently been shown to be in many cases an active process, mediated by the protein ninjurin-18 (NINJ1). Here we resolve the structure of NINJ1 and the mechanism by which it ruptures membranes. Super-resolution microscopy reveals that NINJ1 clusters into structurally diverse assemblies in the membranes of dying cells, in particular large, filamentous assemblies with branched morphology. A cryo-electron microscopy structure of NINJ1 filaments shows a tightly packed fence-like array of transmembrane α-helices. Filament directionality and stability is defined by two amphipathic α-helices that interlink adjacent filament subunits. The NINJ1 filament features a hydrophilic side and a hydrophobic side, and molecular dynamics simulations show that it can stably cap membrane edges. The function of the resulting supramolecular arrangement was validated by site-directed mutagenesis. Our data thus suggest that, during lytic cell death, the extracellular α-helices of NINJ1 insert into the plasma membrane to polymerize NINJ1 monomers into amphipathic filaments that rupture the plasma membrane. The membrane protein NINJ1 is therefore an interactive component of the eukaryotic cell membrane that functions as an in-built breaking point in response to activation of cell death.
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Affiliation(s)
- Morris Degen
- Biozentrum, University of Basel, Basel, Switzerland
| | - José Carlos Santos
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Kristyna Pluhackova
- Stuttgart Center for Simulation Science, Cluster of Excellence EXC 2075, University of Stuttgart, Stuttgart, Germany.
| | | | - Saray Ramos
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | | | - Ella Hartenian
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland
| | - Undina Guillerm
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Stefania A Mari
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
| | - Bastian Kohl
- Biozentrum, University of Basel, Basel, Switzerland
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Basel, Switzerland
| | - Paul Schanda
- Institute of Science and Technology Austria (ISTA), Klosterneuburg, Austria
| | - Timm Maier
- Biozentrum, University of Basel, Basel, Switzerland
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland
| | - Christian Sieben
- Nanoscale Infection Biology Group, Department of Cell Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
- Institute for Genetics, Technische Universität Braunschweig, Braunschweig, Germany
| | - Petr Broz
- Department of Immunobiology, University of Lausanne, Epalinges, Switzerland.
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11
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Wang HC, Lin SJ, Wang HC, Kumar R, Le PT, Leu JH. A bacterial binary toxin system that kills both insects and aquatic crustaceans: Photorhabdus insect-related toxins A and B. PLoS Pathog 2023; 19:e1011330. [PMID: 37141203 PMCID: PMC10159206 DOI: 10.1371/journal.ppat.1011330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023] Open
Abstract
Photorhabdus insect-related toxins A and B (PirA and PirB) were first recognized as insecticidal toxins from Photorhabdus luminescens. However, subsequent studies showed that their homologs from Vibrio parahaemolyticus also play critical roles in the pathogenesis of acute hepatopancreatic necrosis disease (AHPND) in shrimps. Based on the structural features of the PirA/PirB toxins, it was suggested that they might function in the same way as a Bacillus thuringiensis Cry pore-forming toxin. However, unlike Cry toxins, studies on the PirA/PirB toxins are still scarce, and their cytotoxic mechanism remains to be clarified. In this review, based on our studies of V. parahaemolyticus PirAvp/PirBvp, we summarize the current understanding of the gene locations, expression control, activation, and cytotoxic mechanism of this type of toxin. Given the important role these toxins play in aquatic disease and their potential use in pest control applications, we also suggest further topics for research. We hope the information presented here will be helpful for future PirA/PirB studies.
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Affiliation(s)
- Hao-Ching Wang
- Graduate Institute of Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan, Republic of China
- The PhD Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University and Academia Sinica, Taipei, Taiwan, Republic of China
- International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Shin-Jen Lin
- International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Han-Ching Wang
- International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan, Republic of China
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Ramya Kumar
- International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan, Taiwan, Republic of China
- Department of Biotechnology and Bioindustry Sciences, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Phuoc Thien Le
- Graduate Institute of Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan, Republic of China
| | - Jiann-Horng Leu
- Institute of Marine Biology, National Taiwan Ocean University, Keelung, Taiwan, Republic of China
- Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung, Taiwan, Republic of China
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12
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Mishra S, Roy A, Dutta S. Cryo-EM-based structural insights into supramolecular assemblies of γ-hemolysin from S. aureus reveal the pore formation mechanism. Structure 2023:S0969-2126(23)00085-0. [PMID: 37019111 DOI: 10.1016/j.str.2023.03.009] [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: 10/15/2022] [Revised: 01/31/2023] [Accepted: 03/10/2023] [Indexed: 04/07/2023]
Abstract
γ-Hemolysin (γ-HL) is a hemolytic and leukotoxic bicomponent β-pore-forming toxin (β-PFT), a potent virulence factor from the Staphylococcus aureus Newman strain. In this study, we performed single-particle cryoelectron microscopy (cryo-EM) of γ-HL in a lipid environment. We observed clustering and square lattice packing of octameric HlgAB pores on the membrane bilayer and an octahedral superassembly of octameric pore complexes that we resolved at resolution of 3.5 Å. Our atomic model further demonstrated the key residues involved in hydrophobic zipping between the rim domains of adjacent octameric complexes, providing additional structural stability in PFTs post oligomerization. We also observed extra densities at the octahedral and octameric interfaces, providing insights into the plausible lipid-binding residues involved for HlgA and HlgB components. Furthermore, the hitherto elusive N-terminal region of HlgA was also resolved in our cryo-EM map, and an overall mechanism of pore formation for bicomponent β-PFTs is proposed.
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Affiliation(s)
- Suman Mishra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Anupam Roy
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
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13
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Margheritis E, Kappelhoff S, Cosentino K. Pore-Forming Proteins: From Pore Assembly to Structure by Quantitative Single-Molecule Imaging. Int J Mol Sci 2023; 24:ijms24054528. [PMID: 36901959 PMCID: PMC10003378 DOI: 10.3390/ijms24054528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/11/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
Pore-forming proteins (PFPs) play a central role in many biological processes related to infection, immunity, cancer, and neurodegeneration. A common feature of PFPs is their ability to form pores that disrupt the membrane permeability barrier and ion homeostasis and generally induce cell death. Some PFPs are part of the genetically encoded machinery of eukaryotic cells that are activated against infection by pathogens or in physiological programs to carry out regulated cell death. PFPs organize into supramolecular transmembrane complexes that perforate membranes through a multistep process involving membrane insertion, protein oligomerization, and finally pore formation. However, the exact mechanism of pore formation varies from PFP to PFP, resulting in different pore structures with different functionalities. Here, we review recent insights into the molecular mechanisms by which PFPs permeabilize membranes and recent methodological advances in their characterization in artificial and cellular membranes. In particular, we focus on single-molecule imaging techniques as powerful tools to unravel the molecular mechanistic details of pore assembly that are often obscured by ensemble measurements, and to determine pore structure and functionality. Uncovering the mechanistic elements of pore formation is critical for understanding the physiological role of PFPs and developing therapeutic approaches.
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14
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Shen Q, Xiong Q, Zhou K, Feng Q, Liu L, Tian T, Wu C, Xiong Y, Melia TJ, Lusk CP, Lin C. Functionalized DNA-Origami-Protein Nanopores Generate Large Transmembrane Channels with Programmable Size-Selectivity. J Am Chem Soc 2023; 145:1292-1300. [PMID: 36577119 PMCID: PMC9852090 DOI: 10.1021/jacs.2c11226] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The DNA-origami technique has enabled the engineering of transmembrane nanopores with programmable size and functionality, showing promise in building biosensors and synthetic cells. However, it remains challenging to build large (>10 nm), functionalizable nanopores that spontaneously perforate lipid membranes. Here, we take advantage of pneumolysin (PLY), a bacterial toxin that potently forms wide ring-like channels on cell membranes, to construct hybrid DNA-protein nanopores. This PLY-DNA-origami complex, in which a DNA-origami ring corrals up to 48 copies of PLY, targets the cholesterol-rich membranes of liposomes and red blood cells, readily forming uniformly sized pores with an average inner diameter of ∼22 nm. Such hybrid nanopores facilitate the exchange of macromolecules between perforated liposomes and their environment, with the exchange rate negatively correlating with the macromolecule size (diameters of gyration: 8-22 nm). Additionally, the DNA ring can be decorated with intrinsically disordered nucleoporins to further restrict the diffusion of traversing molecules, highlighting the programmability of the hybrid nanopores. PLY-DNA pores provide an enabling biophysical tool for studying the cross-membrane translocation of ultralarge molecules and open new opportunities for analytical chemistry, synthetic biology, and nanomedicine.
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Affiliation(s)
- Qi Shen
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
- Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Qiancheng Xiong
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
- Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Kaifeng Zhou
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Qingzhou Feng
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
- Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Longfei Liu
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
- Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
| | - Taoran Tian
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
| | - Chunxiang Wu
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, Connecticut 06511, United States
| | - Thomas J. Melia
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
| | - C. Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
| | - Chenxiang Lin
- Department of Cell Biology, Yale School of Medicine, 333 Cedar Street, New Haven, Connecticut 06520, United States
- Nanobiology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut 06516, United States
- Department of Biomedical Engineering, Yale University, 17 Hillhouse Ave, New Haven, Connecticut 06511, United States
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15
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Ariyama H. Visualizing the Domino-Like Prepore-to-Pore Transition of Streptolysin O by High-Speed AFM. J Membr Biol 2023; 256:91-103. [PMID: 35980453 PMCID: PMC9884259 DOI: 10.1007/s00232-022-00261-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/02/2022] [Indexed: 02/07/2023]
Abstract
Pore-forming proteins (PFPs) are produced by various organisms, including pathogenic bacteria, and form pores within the target cell membrane. Streptolysin O (SLO) is a PFP produced by Streptococcus pyogenes and forms high-order oligomers on the membrane surface. In this prepore state, multiple α-helices in domain 3 of each subunit exist as unfolded structures and transiently interact with each other. They subsequently transition into transmembrane β-hairpins (TMHs) and form pores with diameters of 20-30 nm. However, in this pore formation process, the trigger of the transition in a subunit and collaboration between subunits remains elusive. Here, I observed the dynamic pore formation process using high-speed atomic force microscopy. During the oligomer transition process, each subunit was sequentially inserted into the membrane, propagating along the oligomer in a domino-like fashion (chain reaction). This process also occurred on hybrid oligomers containing wildtype and mutant subunits, which cannot insert into the membrane because of an introduced disulfide bond. Furthermore, propagation still occurred when an excessive force was added to hybrid oligomers in the prepore state. Based on the observed chain reactions, I estimate the free energies and forces that trigger the transition in a subunit. Furthermore, I hypothesize that the collaboration between subunits is related to the structure of their TMH regions and interactions between TMH-TMH and TMH-lipid molecules.
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Affiliation(s)
- Hirotaka Ariyama
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192 Japan
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16
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Johnstone BA, Joseph R, Christie MP, Morton CJ, McGuiness C, Walsh JC, Böcking T, Tweten RK, Parker MW. Cholesterol-dependent cytolysins: The outstanding questions. IUBMB Life 2022; 74:1169-1179. [PMID: 35836358 PMCID: PMC9712165 DOI: 10.1002/iub.2661] [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: 06/01/2022] [Accepted: 06/23/2022] [Indexed: 11/06/2022]
Abstract
The cholesterol-dependent cytolysins (CDCs) are a major family of bacterial pore-forming proteins secreted as virulence factors by Gram-positive bacterial species. CDCs are produced as soluble, monomeric proteins that bind specifically to cholesterol-rich membranes, where they oligomerize into ring-shaped pores of more than 30 monomers. Understanding the details of the steps the toxin undergoes in converting from monomer to a membrane-spanning pore is a continuing challenge. In this review we summarize what we know about CDCs and highlight the remaining outstanding questions that require answers to obtain a complete picture of how these toxins kill cells.
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Affiliation(s)
- Bronte A Johnstone
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Riya Joseph
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Michelle P Christie
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Craig J Morton
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Conall McGuiness
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - James C Walsh
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Rodney K Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Michael W Parker
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- Australian Cancer Research Foundation Rational Drug Discovery Centre, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
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17
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Mondal AK, Lata K, Singh M, Chatterjee S, Chauhan A, Puravankara S, Chattopadhyay K. Cryo-EM elucidates mechanism of action of bacterial pore-forming toxins. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184013. [PMID: 35908609 DOI: 10.1016/j.bbamem.2022.184013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/05/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Pore-forming toxins (PFTs) rupture plasma membranes and kill target cells. PFTs are secreted as soluble monomers that undergo drastic structural rearrangements upon interacting with the target membrane and generate transmembrane oligomeric pores. A detailed understanding of the molecular mechanisms of the pore-formation process remains unclear due to limited structural insights regarding the transmembrane oligomeric pore states of the PFTs. However, recent advances in the field of cryo-electron microscopy (cryo-EM) have led to the high-resolution structure determination of the oligomeric pore forms of diverse PFTs. Here, we discuss the pore-forming mechanisms of various PFTs, specifically the mechanistic details contributed by the cryo-EM-based structural studies.
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Affiliation(s)
- Anish Kumar Mondal
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Mahendra Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Shamaita Chatterjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Aakanksha Chauhan
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Sindhoora Puravankara
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali 140306, Punjab, India.
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18
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McGuinness C, Walsh JC, Bayly-Jones C, Dunstone MA, Christie MP, Morton CJ, Parker MW, Böcking T. Single-molecule analysis of the entire perfringolysin O pore formation pathway. eLife 2022; 11:74901. [PMID: 36000711 PMCID: PMC9457685 DOI: 10.7554/elife.74901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 08/16/2022] [Indexed: 11/20/2022] Open
Abstract
The cholesterol-dependent cytolysin perfringolysin O (PFO) is secreted by Clostridium perfringens as a bacterial virulence factor able to form giant ring-shaped pores that perforate and ultimately lyse mammalian cell membranes. To resolve the kinetics of all steps in the assembly pathway, we have used single-molecule fluorescence imaging to follow the dynamics of PFO on dye-loaded liposomes that lead to opening of a pore and release of the encapsulated dye. Formation of a long-lived membrane-bound PFO dimer nucleates the growth of an irreversible oligomer. The growing oligomer can insert into the membrane and open a pore at stoichiometries ranging from tetramers to full rings (~35 mers), whereby the rate of insertion increases linearly with the number of subunits. Oligomers that insert before the ring is complete continue to grow by monomer addition post insertion. Overall, our observations suggest that PFO membrane insertion is kinetically controlled.
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Affiliation(s)
- Conall McGuinness
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney, Australia
| | - James C Walsh
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney, Australia
| | - Charles Bayly-Jones
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Michelle P Christie
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, Australia
| | - Craig J Morton
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, Australia
| | - Michael W Parker
- Australian Cancer Research Foundation Rational Drug Discovery Centre, St Vincents Institute of Medical Research, Fitzroy, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science, University of New South Wales, Sydney, Australia
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19
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Guo T, Liu P, Wang Z, Zheng Y, Huang W, Kong D, Ding L, Lv Q, Wang Z, Jiang H, Jiang Y, Sun L. Luteolin Binds Streptolysin O Toxin and Inhibits Its Hemolytic Effects and Cytotoxicity. Front Pharmacol 2022; 13:942180. [PMID: 35873567 PMCID: PMC9300923 DOI: 10.3389/fphar.2022.942180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/14/2022] [Indexed: 11/13/2022] Open
Abstract
Group A streptococcus (GAS, Streptococcus pyogenes) is a common pathogen that can cause a variety of human diseases. Streptolysin O (SLO) is an exotoxin produced by GAS. It is a pore-forming toxin (PFT) that exhibits high in vivo toxicity. SLO enables GAS to evade phagocytosis and clearance by neutrophils, induces eukaryotic cell lysis, and activates inflammatory bodies. Luteolin is a natural compound that is produced by a wide range of plant species, and recent studies have shown that luteolin can inhibit the growth and alter the morphological of GAS. Here, we reported that luteolin can weaken the cytotoxicity and hemolytic activity of SLO in vitro. Briefly, luteolin bound SLO with high affinity, inhibited its dissolution of erythrocytes, affected its conformational stability and inhibited the formation of oligomers. To further verify the protective effect of luteolin, we used an in vitro SLO-induced human laryngeal carcinoma epithelial type-2 cells (HEp-2) model. Notably, our results showed luteolin protected HEp-2 cells from SLO induced cytotoxicity and changed in cell membrane permeability. In addition, we explored the role of luteolin in protecting mice from GAS-mediated injury using an aerosolized lung delivery model, and our results indicate that luteolin increases murine survival rate following inoculation with a lethal dose of GAS, and that survival was also associated with decreased pathological damage to lung tissue. Our results suggest that luteolin may be a novel drug candidate for the treatment of GAS infection.
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Affiliation(s)
- Tingting Guo
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Peng Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Zeyu Wang
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Yuling Zheng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Wenhua Huang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Decong Kong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Lizhong Ding
- Affiliated Hospital to Changchun University of Chinese Medicine, Changchun, China
| | - Qingyu Lv
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
| | - Zhongtian Wang
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
| | - Hua Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
- *Correspondence: Hua Jiang, ; Yongqiang Jiang, ; Liping Sun,
| | - Yongqiang Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences (AMMS), Beijing, China
- *Correspondence: Hua Jiang, ; Yongqiang Jiang, ; Liping Sun,
| | - Liping Sun
- College of Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- *Correspondence: Hua Jiang, ; Yongqiang Jiang, ; Liping Sun,
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20
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Couves EC, Bubeck D. Capturing pore-forming intermediates of MACPF and binary toxin assemblies by cryoEM. Curr Opin Struct Biol 2022; 75:102401. [PMID: 35700576 DOI: 10.1016/j.sbi.2022.102401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/28/2022] [Accepted: 05/09/2022] [Indexed: 11/15/2022]
Abstract
Deployed by both pathogenic bacteria and host immune systems, pore-forming proteins rupture target membranes and can serve as conduits for effector proteins. Understanding how these proteins work relies on capturing assembly intermediates. Advances in cryoEM allowing in silico purification of heterogeneous assemblies has led to new insights into two main classes of pore-forming proteins: membrane attack complex perforin (MACPF) proteins and binary toxins. The structure of an immune activation complex, sMAC, shows how pores form by sequential templating and insertion of β-hairpins. CryoEM structures of bacterial binary toxins present a series of transitions along the pore formation pathway and reveal a general mechanism of effector protein translocation. Future developments in time-resolved cryoEM could capture and place short-lived states along the trajectory of pore-formation.
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Affiliation(s)
- Emma C Couves
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, SW7 2AZ, United Kingdom. https://twitter.com/@EmmaCouves
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, London, SW7 2AZ, United Kingdom.
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21
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Pereira JM, Xu S, Leong JM, Sousa S. The Yin and Yang of Pneumolysin During Pneumococcal Infection. Front Immunol 2022; 13:878244. [PMID: 35529870 PMCID: PMC9074694 DOI: 10.3389/fimmu.2022.878244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 03/23/2022] [Indexed: 12/15/2022] Open
Abstract
Pneumolysin (PLY) is a pore-forming toxin produced by the human pathobiont Streptococcus pneumoniae, the major cause of pneumonia worldwide. PLY, a key pneumococcal virulence factor, can form transmembrane pores in host cells, disrupting plasma membrane integrity and deregulating cellular homeostasis. At lytic concentrations, PLY causes cell death. At sub-lytic concentrations, PLY triggers host cell survival pathways that cooperate to reseal the damaged plasma membrane and restore cell homeostasis. While PLY is generally considered a pivotal factor promoting S. pneumoniae colonization and survival, it is also a powerful trigger of the innate and adaptive host immune response against bacterial infection. The dichotomy of PLY as both a key bacterial virulence factor and a trigger for host immune modulation allows the toxin to display both "Yin" and "Yang" properties during infection, promoting disease by membrane perforation and activating inflammatory pathways, while also mitigating damage by triggering host cell repair and initiating anti-inflammatory responses. Due to its cytolytic activity and diverse immunomodulatory properties, PLY is integral to every stage of S. pneumoniae pathogenesis and may tip the balance towards either the pathogen or the host depending on the context of infection.
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Affiliation(s)
- Joana M. Pereira
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Molecular and Cellular (MC) Biology PhD Program, ICBAS - Instituto de Ciência Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Shuying Xu
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
- Graduate Program in Immunology, Tufts Graduate School of Biomedical Sciences, Boston, MA, United States
| | - John M. Leong
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, United States
| | - Sandra Sousa
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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22
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Abstract
In-cell structural biology aims at extracting structural information about proteins or nucleic acids in their native, cellular environment. This emerging field holds great promise and is already providing new facts and outlooks of interest at both fundamental and applied levels. NMR spectroscopy has important contributions on this stage: It brings information on a broad variety of nuclei at the atomic scale, which ensures its great versatility and uniqueness. Here, we detail the methods, the fundamental knowledge, and the applications in biomedical engineering related to in-cell structural biology by NMR. We finally propose a brief overview of the main other techniques in the field (EPR, smFRET, cryo-ET, etc.) to draw some advisable developments for in-cell NMR. In the era of large-scale screenings and deep learning, both accurate and qualitative experimental evidence are as essential as ever to understand the interior life of cells. In-cell structural biology by NMR spectroscopy can generate such a knowledge, and it does so at the atomic scale. This review is meant to deliver comprehensive but accessible information, with advanced technical details and reflections on the methods, the nature of the results, and the future of the field.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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23
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Ulhuq FR, Mariano G. Bacterial pore-forming toxins. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001154. [PMID: 35333704 PMCID: PMC9558359 DOI: 10.1099/mic.0.001154] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 02/03/2022] [Indexed: 12/11/2022]
Abstract
Pore-forming toxins (PFTs) are widely distributed in both Gram-negative and Gram-positive bacteria. PFTs can act as virulence factors that bacteria utilise in dissemination and host colonisation or, alternatively, they can be employed to compete with rival microbes in polymicrobial niches. PFTs transition from a soluble form to become membrane-embedded by undergoing large conformational changes. Once inserted, they perforate the membrane, causing uncontrolled efflux of ions and/or nutrients and dissipating the protonmotive force (PMF). In some instances, target cells intoxicated by PFTs display additional effects as part of the cellular response to pore formation. Significant progress has been made in the mechanistic description of pore formation for the different PFTs families, but in several cases a complete understanding of pore structure remains lacking. PFTs have evolved recognition mechanisms to bind specific receptors that define their host tropism, although this can be remarkably diverse even within the same family. Here we summarise the salient features of PFTs and highlight where additional research is necessary to fully understand the mechanism of pore formation by members of this diverse group of protein toxins.
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Affiliation(s)
- Fatima R. Ulhuq
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Giuseppina Mariano
- Microbes in Health and Disease Theme, Newcastle University Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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24
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Mechanistic Insights into Gasdermin Pore Formation and Regulation in Pyroptosis. J Mol Biol 2022; 434:167297. [PMID: 34627790 PMCID: PMC8844191 DOI: 10.1016/j.jmb.2021.167297] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 12/11/2022]
Abstract
The gasdermin family is a newly identified class of pore-forming proteins that play as the executioners of pyroptosis, a lytic pro-inflammatory type of cell death triggered by sensing cytosolic infections and danger signals. Upon activation, the gasdermin N-terminal domain translocates to the cell membrane to form pores, which allow the release of proinflammatory cytokines and alarmins, and cause cell lysis. Many structural studies have been conducted in the past few years to investigate the mechanisms of gasdermin proteins in the activation and pore formation. Here, we review these high-resolution structures and highlight the mechanistic insights into the gasdermin activation and regulation that are provided.
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25
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Tanishita Y, Sekiya H, Inohara N, Tsuchiya K, Mitsuyama M, Núñez G, Hara H. Listeria toxin promotes phosphorylation of the inflammasome adaptor ASC through Lyn and Syk to exacerbate pathogen expansion. Cell Rep 2022; 38:110414. [PMID: 35196496 DOI: 10.1016/j.celrep.2022.110414] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 10/08/2021] [Accepted: 01/31/2022] [Indexed: 12/20/2022] Open
Abstract
Inflammasome activation exacerbates infectious disease caused by pathogens such as Listeria monocytogenes, Staphylococcus aureus, and severe acute respiratory syndrome coronavirus 2. Although these pathogens activate host inflammasomes to regulate pathogen expansion, the mechanisms by which pathogen toxins contribute to inflammasome activation remain poorly understood. Here we show that activation of inflammasomes by Listeria infection is promoted by amino acid residue T223 of listeriolysin O (LLO) independently of its pore-forming activity. LLO T223 is critical for phosphorylation of the inflammasome adaptor ASC at amino acid residue Y144 through Lyn-Syk signaling, which is essential for ASC oligomerization. Notably, a Listeria mutant expressing LLO T223A is impaired in inducing ASC phosphorylation and inflammasome activation. Furthermore, the virulence of LLO T223A mutant is markedly attenuated in vivo due to impaired ability to activate the inflammasome. Our results reveal a function of a pathogen toxin that exacerbates infection by promoting phosphorylation of ASC.
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Affiliation(s)
- Yuko Tanishita
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hisateru Sekiya
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Naohiro Inohara
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Kohsuke Tsuchiya
- Division of Immunology and Molecular Biology, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
| | - Masao Mitsuyama
- Department of Microbiology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Gabriel Núñez
- Department of Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hideki Hara
- Department of Microbiology and Immunology, Keio University School of Medicine, Tokyo 160-8582, Japan.
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26
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Kühlbrandt W. Forty years in cryoEM of membrane proteins. Microscopy (Oxf) 2022; 71:i30-i50. [PMID: 35275191 PMCID: PMC8855526 DOI: 10.1093/jmicro/dfab041] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 10/05/2021] [Accepted: 11/10/2021] [Indexed: 12/13/2022] Open
Abstract
In a surprisingly short time, electron cryo-microscopy (cryoEM) has developed from a niche technique in structural biology to a mainstream method practiced in a rapidly growing number of laboratories around the world. From its beginnings about 40 years ago, cryoEM has had a major impact on the study of membrane proteins, in particular the energy-converting systems from bacterial, mitochondrial and chloroplast membranes. Early work on two-dimensional crystals attained resolutions ∼3.5 Å, but at present, single-particle cryoEM delivers much more detailed structures without crystals. Electron cryo-tomography of membranes and membrane-associated proteins adds valuable context, usually at lower resolution. The review ends with a brief outlook on future prospects.
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Affiliation(s)
- Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue Str. 3, Frankfurt am Main 60438, Germany
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27
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Ivanova ME, Lukoyanova N, Malhotra S, Topf M, Trapani JA, Voskoboinik I, Saibil HR. The pore conformation of lymphocyte perforin. SCIENCE ADVANCES 2022; 8:eabk3147. [PMID: 35148176 PMCID: PMC8836823 DOI: 10.1126/sciadv.abk3147] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/17/2021] [Indexed: 05/05/2023]
Abstract
Perforin is a pore-forming protein that facilitates rapid killing of pathogen-infected or cancerous cells by the immune system. Perforin is released from cytotoxic lymphocytes, together with proapoptotic granzymes, to bind to a target cell membrane where it oligomerizes and forms pores. The pores allow granzyme entry, which rapidly triggers the apoptotic death of the target cell. Here, we present a 4-Å resolution cryo-electron microscopy structure of the perforin pore, revealing previously unidentified inter- and intramolecular interactions stabilizing the assembly. During pore formation, the helix-turn-helix motif moves away from the bend in the central β sheet to form an intermolecular contact. Cryo-electron tomography shows that prepores form on the membrane surface with minimal conformational changes. Our findings suggest the sequence of conformational changes underlying oligomerization and membrane insertion, and explain how several pathogenic mutations affect function.
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Affiliation(s)
- Marina E. Ivanova
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Natalya Lukoyanova
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
| | - Sony Malhotra
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Scientific Computing Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Fermi Ave, Harwell, Didcot OX11 0QX, UK
| | - Maya Topf
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Centre for Structural Systems Biology, Leibniz-Institut für Experimentelle Virologie and Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Joseph A. Trapani
- Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Ilia Voskoboinik
- Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Helen R. Saibil
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
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28
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Sengupta N, Mondal AK, Mishra S, Chattopadhyay K, Dutta S. Single-particle cryo-EM reveals conformational variability of the oligomeric VCC β-barrel pore in a lipid bilayer. J Cell Biol 2021; 220:212683. [PMID: 34617964 PMCID: PMC8504180 DOI: 10.1083/jcb.202102035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 08/25/2021] [Accepted: 09/19/2021] [Indexed: 11/22/2022] Open
Abstract
Vibrio cholerae cytolysin (VCC) is a water-soluble, membrane-damaging, pore-forming toxin (PFT) secreted by pathogenic V. cholerae, which causes eukaryotic cell death by altering the plasma membrane permeability. VCC self-assembles on the cell surface and undergoes a dramatic conformational change from prepore to heptameric pore structure. Over the past few years, several high-resolution structures of detergent-solubilized PFTs have been characterized. However, high-resolution structural characterization of small β-PFTs in a lipid environment is still rare. Therefore, we used single-particle cryo-EM to characterize the structure of the VCC oligomer in large unilamellar vesicles, which is the first atomic-resolution cryo-EM structure of VCC. From our study, we were able to provide the first documented visualization of the rim domain amino acid residues of VCC interacting with lipid membrane. Furthermore, cryo-EM characterization of lipid bilayer–embedded VCC suggests interesting conformational variabilities, especially in the transmembrane channel, which could have a potential impact on the pore architecture and assist us in understanding the pore formation mechanism.
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Affiliation(s)
- Nayanika Sengupta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Anish Kumar Mondal
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Suman Mishra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Kausik Chattopadhyay
- Centre for Protein Science, Design and Engineering, Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Punjab, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
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29
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Intracellularly Released Cholesterol from Polymer-Based Delivery Systems Alters Cellular Responses to Pneumolysin and Promotes Cell Survival. Metabolites 2021; 11:metabo11120821. [PMID: 34940579 PMCID: PMC8709088 DOI: 10.3390/metabo11120821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022] Open
Abstract
Cholesterol is highly abundant within all human body cells and modulates critical cellular functions related to cellular plasticity, metabolism, and survival. The cholesterol-binding toxin pneumolysin represents an essential virulence factor of Streptococcus pneumoniae in establishing pneumonia and other pneumococcal infections. Thus, cholesterol scavenging of pneumolysin is a promising strategy to reduce S. pneumoniae induced lung damage. There may also be a second cholesterol-dependent mechanism whereby pneumococcal infection and the presence of pneumolysin increase hepatic sterol biosynthesis. Here we investigated a library of polymer particles varying in size and composition that allow for the cellular delivery of cholesterol and their effects on cell survival mechanisms following pneumolysin exposure. Intracellular delivery of cholesterol by nanocarriers composed of Eudragit E100–PLGA rescued pneumolysin-induced alterations of lipid homeostasis and enhanced cell survival irrespective of neutralization of pneumolysin.
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30
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Challenges and approaches to studying pore-forming proteins. Biochem Soc Trans 2021; 49:2749-2765. [PMID: 34747994 PMCID: PMC8892993 DOI: 10.1042/bst20210706] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/19/2021] [Accepted: 10/06/2021] [Indexed: 02/07/2023]
Abstract
Pore-forming proteins (PFPs) are a broad class of molecules that comprise various families, structural folds, and assembly pathways. In nature, PFPs are most often deployed by their host organisms to defend against other organisms. In humans, this is apparent in the immune system, where several immune effectors possess pore-forming activity. Furthermore, applications of PFPs are found in next-generation low-cost DNA sequencing, agricultural crop protection, pest control, and biosensing. The advent of cryoEM has propelled the field forward. Nevertheless, significant challenges and knowledge-gaps remain. Overcoming these challenges is particularly important for the development of custom, purpose-engineered PFPs with novel or desired properties. Emerging single-molecule techniques and methods are helping to address these unanswered questions. Here we review the current challenges, problems, and approaches to studying PFPs.
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31
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Wu F, Jin X, Guan Z, Lin J, Cai C, Wang L, Li Y, Lin S, Xu P, Gao L. Membrane Nanopores Induced by Nanotoroids via an Insertion and Pore-Forming Pathway. NANO LETTERS 2021; 21:8545-8553. [PMID: 34623162 DOI: 10.1021/acs.nanolett.1c01331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The formation of membrane nanopores is one of the crucial activities of cells and has attracted considerable attention. However, the understanding of their types and mechanisms is still limited. Herein, we report a novel nanopore formation phenomenon achieved through the insertion of polymeric nanotoroids into the cellular membrane. As revealed by theoretical simulations, the nanotoroid can embed in the membrane, leaving a nanopore on the cell. The through-the-cavity wrapping of lipids is critical for the retention of the nanotoroid in the membrane, which is attributed to both a relatively large inner cavity of the nanotoroid and a moderate attraction between the nanotoroid and membrane lipids. Under the guidance of the simulation predictions, experiments using polypeptide toroids as pore-forming agents were performed, confirming the unique biophysical phenomenon. This work demonstrates a distinctive pore-forming pathway, deepens the understanding of the membrane nanopore phenomenon, and assists in the design of advanced pore-forming materials.
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Affiliation(s)
- Fangsheng Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Xiao Jin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Zhou Guan
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Chunhua Cai
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Yongsheng Li
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Pengfei Xu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liang Gao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
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32
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Ilangumaran Ponmalar I, Sarangi NK, Basu JK, Ayappa KG. Pore Forming Protein Induced Biomembrane Reorganization and Dynamics: A Focused Review. Front Mol Biosci 2021; 8:737561. [PMID: 34568431 PMCID: PMC8459938 DOI: 10.3389/fmolb.2021.737561] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Pore forming proteins are a broad class of pathogenic proteins secreted by organisms as virulence factors due to their ability to form pores on the target cell membrane. Bacterial pore forming toxins (PFTs) belong to a subclass of pore forming proteins widely implicated in bacterial infections. Although the action of PFTs on target cells have been widely investigated, the underlying membrane response of lipids during membrane binding and pore formation has received less attention. With the advent of superresolution microscopy as well as the ability to carry out molecular dynamics (MD) simulations of the large protein membrane assemblies, novel microscopic insights on the pore forming mechanism have emerged over the last decade. In this review, we focus primarily on results collated in our laboratory which probe dynamic lipid reorganization induced in the plasma membrane during various stages of pore formation by two archetypal bacterial PFTs, cytolysin A (ClyA), an α-toxin and listeriolysin O (LLO), a β-toxin. The extent of lipid perturbation is dependent on both the secondary structure of the membrane inserted motifs of pore complex as well as the topological variations of the pore complex. Using confocal and superresolution stimulated emission depletion (STED) fluorescence correlation spectroscopy (FCS) and MD simulations, lipid diffusion, cholesterol reorganization and deviations from Brownian diffusion are correlated with the oligomeric state of the membrane bound protein as well as the underlying membrane composition. Deviations from free diffusion are typically observed at length scales below ∼130 nm to reveal the presence of local dynamical heterogeneities that emerge at the nanoscale-driven in part by preferential protein binding to cholesterol and domains present in the lipid membrane. Interrogating the lipid dynamics at the nanoscale allows us further differentiate between binding and pore formation of β- and α-PFTs to specific domains in the membrane. The molecular insights gained from the intricate coupling that occurs between proteins and membrane lipids and receptors during pore formation are expected to improve our understanding of the virulent action of PFTs.
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Affiliation(s)
| | - Nirod K. Sarangi
- School of Chemical Science, Dublin City University, Dublin, Ireland
| | - Jaydeep K. Basu
- Department of Physics, Indian Institute of Science, Bangalore, India
| | - K. Ganapathy Ayappa
- Center for BioSystems Science and Engineering, Indian Institute of Science, Bangalore, India
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
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34
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Kulma M, Anderluh G. Beyond pore formation: reorganization of the plasma membrane induced by pore-forming proteins. Cell Mol Life Sci 2021; 78:6229-6249. [PMID: 34387717 PMCID: PMC11073440 DOI: 10.1007/s00018-021-03914-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 07/09/2021] [Accepted: 08/03/2021] [Indexed: 12/23/2022]
Abstract
Pore-forming proteins (PFPs) are a heterogeneous group of proteins that are expressed and secreted by a wide range of organisms. PFPs are produced as soluble monomers that bind to a receptor molecule in the host cell membrane. They then assemble into oligomers that are incorporated into the lipid membrane to form transmembrane pores. Such pore formation alters the permeability of the plasma membrane and is one of the most common mechanisms used by PFPs to destroy target cells. Interestingly, PFPs can also indirectly manipulate diverse cellular functions. In recent years, increasing evidence indicates that the interaction of PFPs with lipid membranes is not only limited to pore-induced membrane permeabilization but is also strongly associated with extensive plasma membrane reorganization. This includes lateral rearrangement and deformation of the lipid membrane, which can lead to the disruption of target cell function and finally death. Conversely, these modifications also constitute an essential component of the membrane repair system that protects cells from the lethal consequences of pore formation. Here, we provide an overview of the current knowledge on the changes in lipid membrane organization caused by PFPs from different organisms.
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Affiliation(s)
- Magdalena Kulma
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia.
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
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35
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Mondal AK, Chattopadhyay K. Structures and functions of the membrane-damaging pore-forming proteins. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:241-288. [PMID: 35034720 DOI: 10.1016/bs.apcsb.2021.07.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Pore-forming proteins (PFPs) of the diverse life forms have emerged as the potent cell-killing entities owing to their specialized membrane-damaging properties. PFPs have the unique ability to perforate the plasma membranes of their target cells, and they exert this functionality by creating oligomeric pores in the membrane lipid bilayer. Pathogenic bacteria employ PFPs as toxins to execute their virulence mechanisms, whereas in the higher vertebrates PFPs are deployed as the part of the immune system and to generate inflammatory responses. PFPs are the unique dimorphic proteins that are generally synthesized as water-soluble molecules, and transform into membrane-inserted oligomeric pore assemblies upon interacting with the target membranes. In spite of sharing very little sequence similarity, PFPs from diverse organisms display incredible structural similarity. Yet, at the same time, structure-function mechanisms of the PFPs document remarkable versatility. Such notions establish PFPs as the fascinating model system to explore variety of unsolved issues pertaining to the structure-function paradigm of the proteins that interact and act in the membrane environment. In this article, we discuss our current understanding regarding the structural basis of the pore-forming functions of the diverse class of PFPs. We attempt to highlight the similarities and differences in their structures, membrane pore-formation mechanisms, and their implications for the various biological processes, ranging from the bacterial virulence mechanisms to the inflammatory immune response generation in the higher animals.
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Affiliation(s)
- Anish Kumar Mondal
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Mohali, Punjab, India.
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Ilangumaran Ponmalar I, Ayappa KG, Basu JK. Bacterial protein listeriolysin O induces nonmonotonic dynamics because of lipid ejection and crowding. Biophys J 2021; 120:3040-3049. [PMID: 34214525 DOI: 10.1016/j.bpj.2021.06.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 05/27/2021] [Accepted: 06/02/2021] [Indexed: 01/15/2023] Open
Abstract
Membrane-bound protein complexes involving pore forming toxins (PFTs) released by virulent bacteria are known to form transmembrane pores leading to host cell lysis. Developing alternative strategies against PFT mediated bacterial virulence factors requires an understanding of the cellular membrane response. However, membrane disruption and related lipid reorganization events during attack by PFTs remain largely unexplored. We report counterintuitive and nonmonotonic variations in lipid diffusion, measured using confocal fluorescence correlation spectroscopy, due to interplay of lipid ejection and crowding by membrane-bound oligomers of a prototypical cholesterol-dependent cytolysin, listeriolysin O (LLO). The observed dynamical crossover is correlated with concentration dependent transitions of LLO oligomeric state populations from rings to arc-like pore complexes, predicted using a proposed two-state free area-based diffusion model. At low PFT concentrations, a hitherto unexplored regime of increased lipid diffusivity is attributed to lipid ejection events because of a preponderance of ring-like pore states. At higher protein concentrations in which membrane-inserted arc-like pores dominate, lipid ejection is less efficient and the ensuing crowding results in a lowering of lipid diffusion. These variations in lipid dynamics are corroborated by macroscopic rheological response measurements of PFT bound vesicles. Our study correlates PFT oligomeric state transitions, membrane remodeling, and mechanical property variations, providing unique insights into the pore forming mechanisms of cholesterol-dependent cytolysins.
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Affiliation(s)
| | - K Ganapathy Ayappa
- Center for BioSystems Science and Engineering Bengaluru, India; Department of Chemical Engineering Bengaluru, India.
| | - Jaydeep K Basu
- Department of Physics, Indian Institute of Science, Bengaluru, India.
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Draberova L, Tumova M, Draber P. Molecular Mechanisms of Mast Cell Activation by Cholesterol-Dependent Cytolysins. Front Immunol 2021; 12:670205. [PMID: 34248949 PMCID: PMC8260682 DOI: 10.3389/fimmu.2021.670205] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 06/08/2021] [Indexed: 12/23/2022] Open
Abstract
Mast cells are potent immune sensors of the tissue microenvironment. Within seconds of activation, they release various preformed biologically active products and initiate the process of de novo synthesis of cytokines, chemokines, and other inflammatory mediators. This process is regulated at multiple levels. Besides the extensively studied IgE and IgG receptors, toll-like receptors, MRGPR, and other protein receptor signaling pathways, there is a critical activation pathway based on cholesterol-dependent, pore-forming cytolytic exotoxins produced by Gram-positive bacterial pathogens. This pathway is initiated by binding the exotoxins to the cholesterol-rich membrane, followed by their dimerization, multimerization, pre-pore formation, and pore formation. At low sublytic concentrations, the exotoxins induce mast cell activation, including degranulation, intracellular calcium concentration changes, and transcriptional activation, resulting in production of cytokines and other inflammatory mediators. Higher toxin concentrations lead to cell death. Similar activation events are observed when mast cells are exposed to sublytic concentrations of saponins or some other compounds interfering with the membrane integrity. We review the molecular mechanisms of mast cell activation by pore-forming bacterial exotoxins, and other compounds inducing cholesterol-dependent plasma membrane perturbations. We discuss the importance of these signaling pathways in innate and acquired immunity.
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Affiliation(s)
- Lubica Draberova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Magda Tumova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
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Cole J, Angyal A, Emes RD, Mitchell TJ, Dickman MJ, Dockrell DH. Pneumolysin Is Responsible for Differential Gene Expression and Modifications in the Epigenetic Landscape of Primary Monocyte Derived Macrophages. Front Immunol 2021; 12:573266. [PMID: 34046027 PMCID: PMC8145618 DOI: 10.3389/fimmu.2021.573266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 04/16/2021] [Indexed: 12/17/2022] Open
Abstract
Epigenetic modifications regulate gene expression in the host response to a diverse range of pathogens. The extent and consequences of epigenetic modification during macrophage responses to Streptococcus pneumoniae, and the role of pneumolysin, a key Streptococcus pneumoniae virulence factor, in influencing these responses, are currently unknown. To investigate this, we infected human monocyte derived macrophages (MDMs) with Streptococcus pneumoniae and addressed whether pneumolysin altered the epigenetic landscape and the associated acute macrophage transcriptional response using a combined transcriptomic and proteomic approach. Transcriptomic analysis identified 503 genes that were differentially expressed in a pneumolysin-dependent manner in these samples. Pathway analysis highlighted the involvement of transcriptional responses to core innate responses to pneumococci including modules associated with metabolic pathways activated in response to infection, oxidative stress responses and NFκB, NOD-like receptor and TNF signalling pathways. Quantitative proteomic analysis confirmed pneumolysin-regulated protein expression, early after bacterial challenge, in representative transcriptional modules associated with innate immune responses. In parallel, quantitative mass spectrometry identified global changes in the relative abundance of histone post translational modifications (PTMs) upon pneumococcal challenge. We identified an increase in the relative abundance of H3K4me1, H4K16ac and a decrease in H3K9me2 and H3K79me2 in a PLY-dependent fashion. We confirmed that pneumolysin blunted early transcriptional responses involving TNF-α and IL-6 expression. Vorinostat, a histone deacetylase inhibitor, similarly downregulated TNF-α production, reprising the pattern observed with pneumolysin. In conclusion, widespread changes in the macrophage transcriptional response are regulated by pneumolysin and are associated with global changes in histone PTMs. Modulating histone PTMs can reverse pneumolysin-associated transcriptional changes influencing innate immune responses, suggesting that epigenetic modification by pneumolysin plays a role in dampening the innate responses to pneumococci.
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Affiliation(s)
- Joby Cole
- Department of Infection, Immunity and Cardiovascular Diseases, University of Sheffield, Sheffield, United Kingdom
- Sheffield Teaching Hospitals NHS FT, Sheffield, United Kingdom
- The Florey Institute, University of Sheffield, Sheffield, United Kingdom
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Adrienn Angyal
- Department of Infection, Immunity and Cardiovascular Diseases, University of Sheffield, Sheffield, United Kingdom
| | - Richard D. Emes
- Advanced Data Analysis Centre, University of Nottingham, Nottingham, United Kingdom
- School of Veterinary Medicine and Science University of Nottingham, Nottingham, United Kingdom
| | - Tim John Mitchell
- Institute of Microbiology and Infection, University of Birmingham, Edinburgh, United Kingdom
| | - Mark J. Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - David H. Dockrell
- MRC Centre for Inflammation Research, University of Edinburgh, Edinburgh, United Kingdom
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39
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Xia S, Zhang Z, Magupalli VG, Pablo JL, Dong Y, Vora SM, Wang L, Fu TM, Jacobson MP, Greka A, Lieberman J, Ruan J, Wu H. Gasdermin D pore structure reveals preferential release of mature interleukin-1. Nature 2021; 593:607-611. [PMID: 33883744 PMCID: PMC8588876 DOI: 10.1038/s41586-021-03478-3] [Citation(s) in RCA: 283] [Impact Index Per Article: 94.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 03/19/2021] [Indexed: 12/12/2022]
Abstract
As organelles of the innate immune system, inflammasomes activate caspase-1 and other inflammatory caspases that cleave gasdermin D (GSDMD). Caspase-1 also cleaves inactive precursors of the interleukin (IL)-1 family to generate mature cytokines such as IL-1β and IL-18. Cleaved GSDMD forms transmembrane pores to enable the release of IL-1 and to drive cell lysis through pyroptosis1-9. Here we report cryo-electron microscopy structures of the pore and the prepore of GSDMD. These structures reveal the different conformations of the two states, as well as extensive membrane-binding elements including a hydrophobic anchor and three positively charged patches. The GSDMD pore conduit is predominantly negatively charged. By contrast, IL-1 precursors have an acidic domain that is proteolytically removed by caspase-110. When permeabilized by GSDMD pores, unlysed liposomes release positively charged and neutral cargoes faster than negatively charged cargoes of similar sizes, and the pores favour the passage of IL-1β and IL-18 over that of their precursors. Consistent with these findings, living-but not pyroptotic-macrophages preferentially release mature IL-1β upon perforation by GSDMD. Mutation of the acidic residues of GSDMD compromises this preference, hindering intracellular retention of the precursor and secretion of the mature cytokine. The GSDMD pore therefore mediates IL-1 release by electrostatic filtering, which suggests the importance of charge in addition to size in the transport of cargoes across this large channel.
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Affiliation(s)
- Shiyu Xia
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Zhibin Zhang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Venkat Giri Magupalli
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Juan Lorenzo Pablo
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ying Dong
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Setu M Vora
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Longfei Wang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Tian-Min Fu
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH, USA
- The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California San Francisco, San Francisco, CA, USA
| | - Anna Greka
- Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Judy Lieberman
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Jianbin Ruan
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Department of Immunology, University of Connecticut Health Center, Farmington, CT, USA.
| | - Hao Wu
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
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40
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The molecular mechanisms of listeriolysin O-induced lipid membrane damage. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183604. [PMID: 33722646 DOI: 10.1016/j.bbamem.2021.183604] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/05/2021] [Accepted: 03/05/2021] [Indexed: 12/22/2022]
Abstract
Listeria monocytogenes is an intracellular food-borne pathogen that causes listeriosis, a severe and potentially life-threatening disease. Listeria uses a number of virulence factors to proliferate and spread to various cells and tissues. In this process, three bacterial virulence factors, the pore-forming protein listeriolysin O and phospholipases PlcA and PlcB, play a crucial role. Listeriolysin O belongs to a family of cholesterol-dependent cytolysins that are mostly expressed by gram-positive bacteria. Its unique structural features in an otherwise conserved three-dimensional fold, such as the acidic triad and proline-glutamate-serine-threonine-like sequence, enable the regulation of its intracellular activity as well as distinct extracellular functions. The stability of listeriolysin O is pH- and temperature-dependent, and this provides another layer of control of its activity in cells. Moreover, many recent studies have demonstrated a unique mechanism of pore formation by listeriolysin O, i.e., the formation of arc-shaped oligomers that can subsequently fuse to form membrane defects of various shapes and sizes. During listerial invasion of host cells, these membrane defects can disrupt phagosome membranes, allowing bacteria to escape into the cytosol and rapidly multiply. The activity of listeriolysin O is profoundly dependent on the amount and accessibility of cholesterol in the lipid membrane, which can be modulated by the phospholipase PlcB. All these prominent features of listeriolysin O play a role during different stages of the L. monocytogenes life cycle by promoting the proliferation of the pathogen while mitigating excessive damage to its replicative niche in the cytosol of the host cell.
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Abstract
CryoEM has become the method of choice for determining the structure of large macromolecular complexes in multiple conformations, at resolutions where unambiguous atomic models can be built. Two effects that have limited progress in single-particle cryoEM are (i) beam-induced movement during image acquisition and (ii) protein adsorption and denaturation at the air-water interface during specimen preparation. While beam-induced movement now appears to have been resolved by all-gold specimen support grids with very small holes, surface effects at the air-water interface are a persistent problem. Strategies to overcome these effects include the use of alternative support films and new techniques for specimen deposition. We examine the future potential of recording perfect images of biological samples for routine structure determination at atomic resolution.
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42
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Gilbert RJC. Electron microscopy as a critical tool in the determination of pore forming mechanisms in proteins. Methods Enzymol 2021; 649:71-102. [PMID: 33712203 DOI: 10.1016/bs.mie.2021.01.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Electron microscopy has consistently played an important role in the description of pore-forming protein systems. The discovery of pore-forming proteins has depended on visualization of the structural pores formed by their oligomeric protein complexes, and as electron microscopy has advanced technologically so has the degree of insight it has been able to give. This review considers a large number of published studies of pore-forming complexes in prepore and pore states determined using single-particle cryo-electron microscopy. Sample isolation and preparation, imaging and image analysis, structure determination and optimization of results are all discussed alongside challenges which pore-forming proteins particularly present. The review also considers the use made of cryo-electron tomography to study pores within their membrane environment and which will prove an increasingly important approach for the future.
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Affiliation(s)
- Robert J C Gilbert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, United Kingdom.
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43
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Desikan R, Behera A, Maiti PK, Ayappa KG. Using multiscale molecular dynamics simulations to obtain insights into pore forming toxin mechanisms. Methods Enzymol 2021; 649:461-502. [PMID: 33712196 DOI: 10.1016/bs.mie.2021.01.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pore forming toxins (PFTs) are virulent proteins released by several species, including many strains of bacteria, to attack and kill host cells. In this article, we focus on the utility of molecular dynamics (MD) simulations and the molecular insights gleaned from these techniques on the pore forming pathways of PFTs. In addition to all-atom simulations which are widely used, coarse-grained MARTINI models and structure-based models have also been used to study PFTs. Here, the emphasis is on methods and techniques involved while setting up, monitoring, and evaluating properties from MD simulations of PFTs in a membrane environment. We draw from several case studies to illustrate how MD simulations have provided molecular insights into protein-protein and protein-lipid interactions, lipid dynamics, conformational transitions and structures of both the oligomeric intermediates and assembled pore structures.
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Affiliation(s)
- Rajat Desikan
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
| | - Amit Behera
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru, India
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India; Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India.
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Abstract
Pore-forming proteins (PFPs) include virulence factors that are produced by many pathogenic bacteria. However, PFPs also comprise non-virulence factors, such as apoptotic Bcl2-like proteins, and also occur in non-pathogenic bacteria and indeed in all kingdoms of life. Pore-forming proteins are an ancient class of proteins, which are tremendously powerful in damaging cell membranes. In general, upon binding to lipid membranes, they convert from the soluble monomeric form into an oligomeric state, and then undergo a dramatic conformational change to form transmembrane pores. Thus, PFPs render the plasma membrane of their target cells permeable to solutes, potentially leading to cell death, or to more subtle manipulations of cellular functions. Recent cryo-EM and X-ray crystallography studies revealed high-resolution structures of several PFPs in their pre-pore and pore states, however many aspects regarding the cues that induce pore formation, the pre-pore to pore conformational transition, the mechanism of membrane permeation and associated dynamics are still less well understood, and direct visualization of the dynamics of these transitions are missing. Using high-speed atomic force microscopy (HS-AFM), the kinetics of oligomerization and the pre-pore to pore transition dynamics of various PFPs, such as Listeriolysin O (LLO), lysenin, and Perforin-2 (PFN2), could be studied. These studies revealed that LLO does not form pores of regular shape or size, but rather forms membrane inserted arcs that propagate and damage lipid membranes as lineactants. In contrast, lysenin forms stable pre-pore and pore nonameric rings and HS-AFM allowed to study their diffusion on and the pH-dependent insertion into the membrane. Similarly, PFN2 underwent pre-pore to pore transition upon acidification. The openness of the HS-AFM system allowed the transition to be imaged in real time and revealed that all observed molecules transitioned into the pore state within 3s. In this chapter, we detail protocols to prepare lipids, form supported lipid bilayers, and provide guidelines for real-time, real-space HS-AFM observations of PFPs in action.
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45
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Evans JC, Tweten RK. How protein engineering has revealed the molecular mechanisms of pore-forming toxins. Methods Enzymol 2021; 649:47-70. [PMID: 33712197 DOI: 10.1016/bs.mie.2021.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Pore-forming proteins are found in prokaryotes, vertebrates, and invertebrates, and when involved in pathogenic processes they are classified as pore-forming toxins (PFTs). The use of gene engineering methods in combination with the information provided by the high-resolution crystal structures of the PFTs have allowed investigators to gain a deep understanding of their pore-forming mechanisms. In this chapter, we discuss how protein engineering has helped us and others to reveal the molecular mechanisms of pore formation by prokaryotic PFTs with an emphasis on our experiences with the cholesterol-dependent cytolysins (CDCs).
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Affiliation(s)
- Jordan C Evans
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Rodney K Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States.
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46
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Abstract
Pore forming proteins are released as water-soluble monomers that form-mostly oligomeric-pores in target membranes. Our understanding of such pore formation relies in part on the direct visualization of their assemblies on and in the membrane. Here, we discuss the application of atomic force microscopy (AFM) to visualize and understand membrane pore formation, illustrated specifically by studies of proteins of the MACPF/CDC superfamily on supported lipid bilayers. Besides detailed protocols, we also point out common imaging artefacts and strategies to avoid them, and briefly outline how AFM can be effectively used in conjunction with other methods.
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Affiliation(s)
- Adrian W Hodel
- Killer Cell Biology Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Katharine Hammond
- National Physical Laboratory, Teddington, United Kingdom; London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Physics & Astronomy, University College London, London, United Kingdom
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, United Kingdom; Department of Physics & Astronomy, University College London, London, United Kingdom.
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47
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Johnstone BA, Christie MP, Morton CJ, Parker MW. X-ray crystallography shines a light on pore-forming toxins. Methods Enzymol 2021; 649:1-46. [PMID: 33712183 DOI: 10.1016/bs.mie.2021.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A common form of cellular attack by pathogenic bacteria is to secrete pore-forming toxins (PFTs). Capable of forming transmembrane pores in various biological membranes, PFTs have also been identified in a diverse range of other organisms such as sea anemones, earthworms and even mushrooms and trees. The mechanism of pore formation by PFTs is associated with substantial conformational changes in going from the water-soluble to transmembrane states of the protein. The determination of the crystal structures for numerous PFTs has shed much light on our understanding of these proteins. Other than elucidating the atomic structural details of PFTs and the conformational changes that must occur for pore formation, crystal structures have revealed structural homology that has led to the discovery of new PFTs and new PFT families. Here we review some key crystallographic results together with complimentary approaches for studying PFTs. We discuss how these studies have impacted our understanding of PFT function and guided research into biotechnical applications.
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Affiliation(s)
- Bronte A Johnstone
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Michelle P Christie
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Craig J Morton
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia; St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia.
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48
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Li Y, Li Y, Mengist HM, Shi C, Zhang C, Wang B, Li T, Huang Y, Xu Y, Jin T. Structural Basis of the Pore-Forming Toxin/Membrane Interaction. Toxins (Basel) 2021; 13:toxins13020128. [PMID: 33572271 PMCID: PMC7914777 DOI: 10.3390/toxins13020128] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/13/2021] [Accepted: 02/02/2021] [Indexed: 12/14/2022] Open
Abstract
With the rapid growth of antibiotic-resistant bacteria, it is urgent to develop alternative therapeutic strategies. Pore-forming toxins (PFTs) belong to the largest family of virulence factors of many pathogenic bacteria and constitute the most characterized classes of pore-forming proteins (PFPs). Recent studies revealed the structural basis of several PFTs, both as soluble monomers, and transmembrane oligomers. Upon interacting with host cells, the soluble monomer of bacterial PFTs assembles into transmembrane oligomeric complexes that insert into membranes and affect target cell-membrane permeability, leading to diverse cellular responses and outcomes. Herein we have reviewed the structural basis of pore formation and interaction of PFTs with the host cell membrane, which could add valuable contributions in comprehensive understanding of PFTs and searching for novel therapeutic strategies targeting PFTs and interaction with host receptors in the fight of bacterial antibiotic-resistance.
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Affiliation(s)
- Yajuan Li
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Yuelong Li
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Hylemariam Mihiretie Mengist
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Cuixiao Shi
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Caiying Zhang
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
| | - Bo Wang
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Tingting Li
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Ying Huang
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
| | - Yuanhong Xu
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, China; (Y.L.); (C.S.); (B.W.); (T.L.); (Y.H.)
- Correspondence: (Y.X.); (T.J.); Tel.: +86-13505694447 (Y.X.); +86-17605607323 (T.J.)
| | - Tengchuan Jin
- Hefei National Laboratory for Physical Sciences at Microscale, Laboratory of Structural Immunology, CAS Key Laboratory of Innate Immunity and Chronic Disease, Division of Life Sciences and Medicine, School of Basic Medical Sciences, University of Science and Technology of China, Hefei 230027, China; (Y.L.); (H.M.M.); (C.Z.)
- Correspondence: (Y.X.); (T.J.); Tel.: +86-13505694447 (Y.X.); +86-17605607323 (T.J.)
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49
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Larpin Y, Besançon H, Babiychuk VS, Babiychuk EB, Köffel R. Small Pore-Forming Toxins Different Membrane Area Binding and Ca 2+ Permeability of Pores Determine Cellular Resistance of Monocytic Cells. Toxins (Basel) 2021; 13:toxins13020126. [PMID: 33572185 PMCID: PMC7914786 DOI: 10.3390/toxins13020126] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/27/2021] [Accepted: 02/04/2021] [Indexed: 01/06/2023] Open
Abstract
Pore-forming toxins (PFTs) form multimeric trans-membrane pores in cell membranes that differ in pore channel diameter (PCD). Cellular resistance to large PFTs (>20 nm PCD) was shown to rely on Ca2+ influx activated membrane repair mechanisms. Small PFTs (<2 nm PCD) were shown to exhibit a high cytotoxic activity, but host cell response and membrane repair mechanisms are less well studied. We used monocytic immune cell lines to investigate the cellular resistance and host membrane repair mechanisms to small PFTs lysenin (Eisenia fetida) and aerolysin (Aeromonas hydrophila). Lysenin, but not aerolysin, is shown to induce Ca2+ influx from the extracellular space and to activate Ca2+ dependent membrane repair mechanisms. Moreover, lysenin binds to U937 cells with higher efficiency as compared to THP-1 cells, which is in line with a high sensitivity of U937 cells to lysenin. In contrast, aerolysin equally binds to U937 or THP-1 cells, but in different plasma membrane areas. Increased aerolysin induced cell death of U937 cells, as compared to THP-1 cells, is suggested to be a consequence of cap-like aerolysin binding. We conclude that host cell resistance to small PFTs attack comprises binding efficiency, pore localization, and capability to induce Ca2+ dependent membrane repair mechanisms.
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Kumar H, Ananthanarayanan V. Friend or Foe? The Role of the Host Cytoskeleton in Cellular Responses to Bacterial Pore Forming Toxins. J Indian Inst Sci 2021. [DOI: 10.1007/s41745-020-00218-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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