1
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Brown CM, Marrink SJ. Modeling membranes in situ. Curr Opin Struct Biol 2024; 87:102837. [PMID: 38744147 DOI: 10.1016/j.sbi.2024.102837] [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: 12/22/2023] [Revised: 03/26/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024]
Abstract
Molecular dynamics simulations of cellular membranes have come a long way-from simple model lipid bilayers to multicomponent systems capturing the crowded and complex nature of real cell membranes. In this opinionated minireview, we discuss the current challenge to simulate the dynamics of membranes in their native environment, in situ, with the prospect of reaching the level of whole cells and cell organelles using an integrative modeling framework.
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Affiliation(s)
- Chelsea M Brown
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands. https://twitter.com/chelseabrowncg
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands. s.j.marrinkrug.nl
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2
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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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3
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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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4
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Kharche S, Yadav M, Hande V, Prakash S, Sengupta D. Improved Protein Dynamics and Hydration in the Martini3 Coarse-Grain Model. J Chem Inf Model 2024; 64:837-850. [PMID: 38291973 DOI: 10.1021/acs.jcim.3c00802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The Martini coarse-grain force-field has emerged as an important framework to probe cellular processes at experimentally relevant time- and length-scales. However, the recently developed version, the Martini3 force-field with the implemented Go̅ model (Martini3Go̅), as well as previous variants of the Martini model have not been benchmarked and rigorously tested for globular proteins. In this study, we consider three globular proteins, ubiquitin, lysozyme, and cofilin, and compare protein dynamics and hydration with observables from experiments and all-atom simulations. We show that the Martini3Go̅ model is able to accurately model the structural and dynamic features of small globular proteins. Overall, the structural integrity of the proteins is maintained, as validated by contact maps, radii of gyration (Rg), and SAXS profiles. The chemical shifts predicted from the ensemble sampled in the simulations are consistent with the experimental data. Further, a good match is observed in the protein-water interaction energetics, and the hydration levels of the residues are similar to atomistic simulations. However, the protein-water interaction dynamics is not accurately represented and appears to depend on the protein structural complexity, residue specificity, and water dynamics. Our work is a step toward testing and assessing the Martini3Go̅ model and provides insights into future efforts to refine Martini models with improved solvation effects and better correspondence to the underlying all-atom systems.
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Affiliation(s)
- Shalmali Kharche
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Manjul Yadav
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Vrushali Hande
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Shikha Prakash
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Durba Sengupta
- CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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5
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Shen Z, Huang D, Jia N, Zhao S, Pei C, Wang Y, Wu Y, Wang X, Shi S, Wang F, He Y, Wang Z. Protective effects of Eleutheroside E against high-altitude pulmonary edema by inhibiting NLRP3 inflammasome-mediated pyroptosis. Biomed Pharmacother 2023; 167:115607. [PMID: 37776644 DOI: 10.1016/j.biopha.2023.115607] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 09/13/2023] [Accepted: 09/26/2023] [Indexed: 10/02/2023] Open
Abstract
Eleutheroside E (EE) is a primary active component of Acanthopanax senticosus, which has been reported to inhibit the expression of inflammatory genes, but the underlying mechanisms remain elusive. High-altitude pulmonary edema (HAPE) is a severe complication of high-altitude exposure occurring after ascent above 2500 m. However, effective and safe preventative measures for HAPE still need to be improved. This study aimed to elucidate the preventative potential and underlying mechanism of EE in HAPE. Rat models of HAPE were established through hypobaric hypoxia. Mechanistically, hypobaric hypoxia aggravates oxidative stress and upregulates (pro)-inflammatory cytokines, activating NOD-like receptor protein 3 (NLRP3) inflammasome-mediated pyroptosis, eventually leading to HAPE. EE suppressed NLRP3 inflammasome-mediated pyroptosis by inhibiting the nuclear translocation of nuclear factor kappa-Β (NF-κB), thereby protecting the lung from HAPE. However, nigericin (Nig), an NLRP3 activator, partially abolished the protective effects of EE. These findings suggest EE is a promising agent for preventing HAPE induced by NLRP3 inflammasome-mediated pyroptosis.
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Affiliation(s)
- Zherui Shen
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Demei Huang
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Nan Jia
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Sijing Zhao
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Caixia Pei
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Yilan Wang
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Yongcan Wu
- Chongqing Medical University, Chongqing 400016, China
| | - Xiaomin Wang
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Shihua Shi
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
| | - Fei Wang
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
| | - Yacong He
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China; State Key Laboratory of Southwestern Chinese Medicine Resources School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.
| | - Zhenxing Wang
- Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
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6
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Jiang H, Liu P, Kang J, Wu J, Gong W, Li X, Li Y, Liu J, Li W, Ni C, Liao B, Wu X, Zhao Y, Ren J. Precise Orchestration of Gasdermins' Pore-Forming Function by Posttranslational Modifications in Health and Disease. Int J Biol Sci 2023; 19:4931-4947. [PMID: 37781519 PMCID: PMC10539709 DOI: 10.7150/ijbs.86869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/04/2023] [Indexed: 10/03/2023] Open
Abstract
Gasdermins (GSDMs) serve as pivotal executors of pyroptosis and play crucial roles in host defence, cytokine secretion, innate immunity, and cancer. However, excessive or inappropriate GSDMs activation is invariably accompanied by exaggerated inflammation and results in tissue damage. In contrast, deficient or impaired activation of GSDMs often fails to promptly eliminate pathogens, leading to the increasing severity of infections. The activity of GSDMs requires meticulous regulation. The dynamic modulation of GSDMs involves many aspects, including autoinhibitory structures, proteolytic cleavage, lipid binding and membrane translocation (oligomerization and pre-pore formation), oligomerization (pore formation) and pore removal for membrane repair. As the most comprehensive and efficient regulatory pathway, posttranslational modifications (PTMs) are widely implicated in the regulation of these aspects. In this comprehensive review, we delve into the complex mechanisms through which a variety of proteases cleave GSDMs to enhance or hinder their function. Moreover, we summarize the intricate regulatory mechanisms of PTMs that govern GSDMs-induced pyroptosis.
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Affiliation(s)
- Haiyang Jiang
- Department of General Surgery, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing 210000, China
| | - Peizhao Liu
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Jiaqi Kang
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Jie Wu
- Jiangsu Provincial Key Laboratory of Critical Care Medicine, Department of Critical Care Medicine, Affiliated Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Wenbin Gong
- Department of General Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China
| | - Xuanheng Li
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Yangguang Li
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Juanhan Liu
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Weizhen Li
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Chujun Ni
- Department of General Surgery, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing 210000, China
| | - Bo Liao
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Xiuwen Wu
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
| | - Yun Zhao
- Department of General Surgery, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing 210000, China
| | - Jianan Ren
- Department of General Surgery, Nanjing BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical University, Nanjing 210000, China
- Research Institute of General Surgery, Affiliated Jinling Hospital, Medical School of Nanjing University, Nanjing 210000, China
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7
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Huang LY, Li ST, Lin SC, Kao CH, Hong CH, Lee CH, Yang LT. Gasdermin A Is Required for Epidermal Cornification during Skin Barrier Regeneration and in an Atopic Dermatitis-Like Model. J Invest Dermatol 2023; 143:1735-1745.e11. [PMID: 36965577 DOI: 10.1016/j.jid.2023.03.1657] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 03/02/2023] [Accepted: 03/04/2023] [Indexed: 03/27/2023]
Abstract
Atopic dermatitis is featured with impaired skin barrier. The stratum corneum and the intercellular tight junctions constitute the permeability barrier, which is essential to protect water loss in the host and prevent pathogen entry. The epidermal barrier is constantly renewed by differentiating keratinocytes through cornification, during which autophagy contributes to elimination of organelles and nucleus. The human GSDMA and its mouse homologs Gsdma1-3 are expressed in the suprabasal epidermis. Although a pyroptotic role of GSDMA/Gsdma1 in host defense against Streptococcus pyogenes has been reported, the physiological function of Gsdma1/a2/a3 in epidermal homeostasis remains elusive. Here, through repeated epidermal barrier disruption, we found that tight junction formation and stratum corneum maturation were defective in the Gsdma1/a3-deficient epidermis. Using comparative gene profiling analysis, mitochondrial respiration measurement, and in vivo tracing of mitophagy, our data indicate that Gsdma1/a3 activation leads to mitochondrial dysfunction and subsequently facilitates mitochondrial turnover and epidermal cornification. In calcipotriol (MC903)-induced atopic dermatitis-like animal model, we showed that Gsdma1/a3-deficiency selectively enhanced the T helper type 2 response. Remarkably, the GSDMA expression is reduced in the epidermis of patients with atopic dermatitis compared with that of normal individuals. Gsdma1/a3-deficiency might be involved in atopic dermatitis pathogenesis, likely through GSDMA-mediated epidermal differentiation and cornification.
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Affiliation(s)
- Li-Ying Huang
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Taiwan
| | - Shao-Ting Li
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Taiwan
| | - Shiang-Chi Lin
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Taiwan
| | - Cheng-Heng Kao
- Center of General Education, Chang Gung University, Taoyuan, Taiwan
| | - Chien-Hui Hong
- Department of Dermatology, School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taiwan; Department of Dermatology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Chih-Hung Lee
- Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - Liang-Tung Yang
- Institute of Cellular and System Medicine, National Health Research Institutes, Zhunan, Taiwan; Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan.
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8
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Devant P, Kagan JC. Molecular mechanisms of gasdermin D pore-forming activity. Nat Immunol 2023:10.1038/s41590-023-01526-w. [PMID: 37277654 DOI: 10.1038/s41590-023-01526-w] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/03/2023] [Indexed: 06/07/2023]
Abstract
The regulated disruption of the plasma membrane, which can promote cell death, cytokine secretion or both is central to organismal health. The protein gasdermin D (GSDMD) is a key player in this process. GSDMD forms membrane pores that can promote cytolysis and the release of interleukin-1 family cytokines into the extracellular space. Recent discoveries have revealed biochemical and cell biological mechanisms that control GSDMD pore-forming activity and its diverse downstream immunological effects. Here, we review these multifaceted regulatory activities, including mechanisms of GSDMD activation by proteolytic cleavage, dynamics of pore assembly, regulation of GSDMD activities by posttranslational modifications, membrane repair and the interplay of GSDMD and mitochondria. We also address recent insights into the evolution of the gasdermin family and their activities in species across the kingdoms of life. In doing so, we hope to condense recent progress and inform future studies in this rapidly moving field in immunology.
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Affiliation(s)
- Pascal Devant
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jonathan C Kagan
- Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA.
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9
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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: 56] [Impact Index Per Article: 56.0] [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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10
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Kong Q, Xia S, Pan X, Ye K, Li Z, Li H, Tang X, Sahni N, Yi SS, Liu X, Wu H, Elowitz MB, Lieberman J, Zhang Z. Alternative splicing of GSDMB modulates killer lymphocyte-triggered pyroptosis. Sci Immunol 2023; 8:eadg3196. [PMID: 37115914 PMCID: PMC10338320 DOI: 10.1126/sciimmunol.adg3196] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/06/2023] [Indexed: 04/30/2023]
Abstract
Granzyme A from killer lymphocytes cleaves gasdermin B (GSDMB) and triggers pyroptosis in targeted human tumor cells, eliciting antitumor immunity. However, GSDMB has a controversial role in pyroptosis and has been linked to both anti- and protumor functions. Here, we found that GSDMB splicing variants are functionally distinct. Cleaved N-terminal (NT) fragments of GSDMB isoforms 3 and 4 caused pyroptosis, but isoforms 1, 2, and 5 did not. The nonfunctional isoforms have a deleted or modified exon 6 and therefore lack a stable belt motif. The belt likely contributes to the insertion of oligomeric GSDMB-NTs into the membrane. Consistently, noncytotoxic GSDMB-NTs blocked pyroptosis caused by cytotoxic GSDMB-NTs in a dominant-negative manner. Upon natural killer (NK) cell attack, GSDMB3-expressing cells died by pyroptosis, whereas GSDMB4-expressing cells died by mixed pyroptosis and apoptosis, and GSDMB1/2-expressing cells died only by apoptosis. GSDMB4 partially resisted NK cell-triggered cleavage, suggesting that only GSDMB3 is fully functional. GSDMB1-3 were the most abundant isoforms in the tested tumor cell lines and were similarly induced by interferon-γ and the chemotherapy drug methotrexate. Expression of cytotoxic GSDMB3/4 isoforms, but not GSDMB1/2 isoforms that are frequently up-regulated in tumors, was associated with better outcomes in bladder and cervical cancers, suggesting that GSDMB3/4-mediated pyroptosis was protective in those tumors. Our study indicates that tumors may block and evade killer cell-triggered pyroptosis by generating noncytotoxic GSDMB isoforms. Therefore, therapeutics that favor the production of cytotoxic GSDMB isoforms by alternative splicing may improve antitumor immunity.
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Affiliation(s)
- Qing Kong
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77054 USA
| | - Shiyu Xia
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Xingxin Pan
- Livestrong Cancer Institutes, Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
| | - Kaixiong Ye
- Department of Genetics, Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
- Institute of Bioinformatics, University of Georgia, Athens, GA, USA
| | - Zhouyihan Li
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77054 USA
| | - Haoyan Li
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77054 USA
| | - Xiaoqiang Tang
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77054 USA
| | - Nidhi Sahni
- Department of Epigenetics and Molecular Carcinogenesis, and Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Quantitative and Computational Biosciences Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - S. Stephen Yi
- Livestrong Cancer Institutes, Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX 78712, USA
- Interdisciplinary Life Sciences Graduate Programs (ILSGP), and Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712, USA
- Oden Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, Austin, TX 78712, USA
| | - Xing Liu
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, 200031 China
| | - Hao Wu
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston MA 02115, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Michael B. Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Judy Lieberman
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston MA 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Zhibin Zhang
- Department of Immunology, University of Texas MD Anderson Cancer Center, Houston, TX 77054 USA
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11
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Zeng Z, You M, Rong R, Fan C, Chen M, Li H, Ji D, Xia X. Translocator protein 18 kDa regulates retinal neuron apoptosis and pyroptosis in glaucoma. Redox Biol 2023; 63:102713. [PMID: 37120931 PMCID: PMC10172718 DOI: 10.1016/j.redox.2023.102713] [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: 04/02/2023] [Accepted: 04/22/2023] [Indexed: 05/02/2023] Open
Abstract
Glaucoma is the leading cause of blindness worldwide. However, our insufficient understanding of the pathogenesis of glaucoma has limited the development of effective treatments. Because recent research has highlighted the importance of non-coding RNAs (ncRNAs) in various diseases, we investigated their roles in glaucoma. Specifically, we detected expression changes of ncRNAs in cell and animal models of acute glaucoma. Further analysis revealed that the Ier2/miR-1839/TSPO axis was critical to cell loss and retinal damage. The knockdown of Ier2, the overexpression of miR-1839, and the silencing of TSPO effectively prevented retinal damage and cell loss. Furthermore, we found that the Ier2/miR-1839/TSPO axis regulated the pyroptosis and apoptosis of retinal neurons through the NLRP3/caspase1/GSDMD, cleaved-caspase3 pathways. In addition to high expression in the retina, TSPO expression was found to be significantly higher in the dorsal lateral geniculate nucleus (DLG) of the brain in the pathologically high intraocular pressure (ph-IOP) rat model, as well as in the peripheral blood mononuclear cells (PBMCs) of glaucoma patients with high IOP. These results indicate that TSPO, which is regulated by Ier2/miR-1839, plays an important role in the pathogenesis of glaucoma, and this study provides a theoretical basis and a new target for the diagnosis and treatment of glaucoma.
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Affiliation(s)
- Zhou Zeng
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Mengling You
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Rong Rong
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Cong Fan
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Meini Chen
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Haibo Li
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Dan Ji
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
| | - Xiaobo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
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12
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Flores-Romero H, Dadsena S, García-Sáez AJ. Mitochondrial pores at the crossroad between cell death and inflammatory signaling. Mol Cell 2023; 83:843-856. [PMID: 36931255 DOI: 10.1016/j.molcel.2023.02.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 03/18/2023]
Abstract
Mitochondria are cellular organelles with a major role in many cellular processes, including not only energy production, metabolism, and calcium homeostasis but also regulated cell death and innate immunity. Their proteobacterial origin makes them a rich source of potent immune agonists, normally hidden within the mitochondrial membrane barriers. Alteration of mitochondrial permeability through mitochondrial pores thus provides efficient mechanisms not only to communicate mitochondrial stress to the cell but also as a key event in the integration of cellular responses. In this regard, eukaryotic cells have developed diverse signaling networks that sense and respond to the release of mitochondrial components into the cytosol and play a key role in controlling cell death and inflammatory pathways. Modulating pore formation at mitochondria through direct or indirect mechanisms may thus open new opportunities for therapy. In this review, we discuss the current understanding of the structure and molecular mechanisms of mitochondrial pores and how they function at the interface between cell death and inflammatory signaling to regulate cellular outcomes.
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Affiliation(s)
- Hector Flores-Romero
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany.
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13
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Akt-mediated mitochondrial metabolism regulates proplatelet formation and platelet shedding post vasopressin exposure. JOURNAL OF THROMBOSIS AND HAEMOSTASIS : JTH 2023; 21:344-358. [PMID: 36700501 DOI: 10.1016/j.jtha.2022.11.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/15/2022] [Accepted: 11/15/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND Platelet shedding from mature megakaryocytes (MKs) in thrombopoiesis is the critical step for elevating circulating platelets fast and efficiently, however, the underlying mechanism is still not well-illustrated, and the therapeutic targets and candidates are even less. OBJECTIVES In order to investigate the mechanisms for platelet shedding after vasopressin treatment and find new therapeutic targets for thrombocytopenia. METHODS Platelet production was evaluated both in vivo and in vitro after arginine vasopressin (AVP) administration. The underlying biological mechanism of AVP-triggered thrombopoiesis were then investigated by a series of molecular and bioinformatics techniques. RESULTS it is observed that proplatelet formation and platelet shedding in the final stages of thrombopoiesis promoted by AVP, an endogenous hormone, can quickly increases peripheral platelets. This rapid elevation is thus able to speed up platelet recovery after radiation as expected. The mechanism analysis reveal that proplatelet formation and platelet release from mature MKs facilitated by AVP is mainly mediated by Akt-regulated mitochondrial metabolism. In particular, phosphorylated Akt regulates mitochondrial metabolism through driving the association of hexokinase-2 with mitochondrial voltage dependent anion channel-1 in AVP-mediated thrombopoiesis. Further studies suggest that this interaction is stabilized by IκBα, the expression of which is controlled by insulin-regulated membrane aminopeptidase. CONCLUSION these data demonstrate that phosphorylated Akt-mediated mitochondrial metabolism regulates platelet shedding from MKs in response to AVP, which will provide new therapeutic targets and further drug discovery clues for thrombocytopenia treatment.
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Li Y, Jiang Q. Uncoupled pyroptosis and IL-1β secretion downstream of inflammasome signaling. Front Immunol 2023; 14:1128358. [PMID: 37090724 PMCID: PMC10117957 DOI: 10.3389/fimmu.2023.1128358] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/24/2023] [Indexed: 04/25/2023] Open
Abstract
Inflammasomes are supramolecular platforms that organize in response to various damage-associated molecular patterns and pathogen-associated molecular patterns. Upon activation, inflammasome sensors (with or without the help of ASC) activate caspase-1 and other inflammatory caspases that cleave gasdermin D and pro-IL-1β/pro-IL-18, leading to pyroptosis and mature cytokine secretion. Pyroptosis enables intracellular pathogen niche disruption and intracellular content release at the cost of cell death, inducing pro-inflammatory responses in the neighboring cells. IL-1β is a potent pro-inflammatory regulator for neutrophil recruitment, macrophage activation, and T-cell expansion. Thus, pyroptosis and cytokine secretion are the two main mechanisms that occur downstream of inflammasome signaling; they maintain homeostasis, drive the innate immune response, and shape adaptive immunity. This review aims to discuss the possible mechanisms, timing, consequences, and significance of the two uncoupling preferences downstream of inflammasome signaling. While pyroptosis and cytokine secretion may be usually coupled, pyroptosis-predominant and cytokine-predominant uncoupling are also observed in a stimulus-, cell type-, or context-dependent manner, contributing to the pathogenesis and development of numerous pathological conditions such as cryopyrin-associated periodic syndromes, LPS-induced sepsis, and Salmonella enterica serovar Typhimurium infection. Hyperactive cells consistently release IL-1β without LDH leakage and pyroptotic death, thereby leading to prolonged inflammation, expanding the lifespans of pyroptosis-resistant neutrophils, and hyperactivating stimuli-challenged macrophages, dendritic cells, monocytes, and specific nonimmune cells. Death inflammasome activation also induces GSDMD-mediated pyroptosis with no IL-1β secretion, which may increase lethality in vivo. The sublytic GSDMD pore formation associated with lower expressions of pyroptotic components, GSDMD-mediated extracellular vesicles, or other GSDMD-independent pathways that involve unconventional secretion could contribute to the cytokine-predominant uncoupling; the regulation of caspase-1 dynamics, which may generate various active species with different activities in terms of GSDMD or pro-IL-1β, could lead to pyroptosis-predominant uncoupling. These uncoupling preferences enable precise reactions to different stimuli of different intensities under specific conditions at the single-cell level, promoting cooperative cell and host fate decisions and participating in the pathogen "game". Appropriate decisions in terms of coupling and uncoupling are required to heal tissues and eliminate threats, and further studies exploring the inflammasome tilt toward pyroptosis or cytokine secretion may be helpful.
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15
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Pore-forming proteins as drivers of membrane permeabilization in cell death pathways. Nat Rev Mol Cell Biol 2022; 24:312-333. [PMID: 36543934 DOI: 10.1038/s41580-022-00564-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 12/24/2022]
Abstract
Regulated cell death (RCD) relies on activation and recruitment of pore-forming proteins (PFPs) that function as executioners of specific cell death pathways: apoptosis regulator BAX (BAX), BCL-2 homologous antagonist/killer (BAK) and BCL-2-related ovarian killer protein (BOK) for apoptosis, gasdermins (GSDMs) for pyroptosis and mixed lineage kinase domain-like protein (MLKL) for necroptosis. Inactive precursors of PFPs are converted into pore-forming entities through activation, membrane recruitment, membrane insertion and oligomerization. These mechanisms involve protein-protein and protein-lipid interactions, proteolytic processing and phosphorylation. In this Review, we discuss the structural rearrangements incurred by RCD-related PFPs and describe the mechanisms that manifest conversion from autoinhibited to membrane-embedded molecular states. We further discuss the formation and maturation of membrane pores formed by BAX/BAK/BOK, GSDMs and MLKL, leading to diverse pore architectures. Lastly, we highlight commonalities and differences of PFP mechanisms involving BAX/BAK/BOK, GSDMs and MLKL and conclude with a discussion on how, in a population of challenged cells, the coexistence of cell death modalities may have profound physiological and pathophysiological implications.
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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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Schaefer SL, Hummer G. Sublytic gasdermin-D pores captured in atomistic molecular simulations. eLife 2022; 11:e81432. [PMID: 36374182 PMCID: PMC9699695 DOI: 10.7554/elife.81432] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Gasdermin-D (GSDMD) is the ultimate effector of pyroptosis, a form of programmed cell death associated with pathogen invasion and inflammation. After proteolytic cleavage by caspases, the GSDMD N-terminal domain (GSDMDNT) assembles on the inner leaflet of the plasma membrane and induces the formation of membrane pores. We use atomistic molecular dynamics simulations to study GSDMDNT monomers, oligomers, and rings in an asymmetric plasma membrane mimetic. We identify distinct interaction motifs of GSDMDNT with phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and phosphatidylserine (PS) headgroups and describe their conformational dependence. Oligomers are stabilized by shared lipid binding sites between neighboring monomers acting akin to double-sided tape. We show that already small GSDMDNT oligomers support stable, water-filled, and ion-conducting membrane pores bounded by curled beta-sheets. In large-scale simulations, we resolve the process of pore formation from GSDMDNT arcs and lipid efflux from partial rings. We find that high-order GSDMDNT oligomers can crack under the line tension of 86 pN created by an open membrane edge to form the slit pores or closed GSDMDNT rings seen in atomic force microscopy experiments. Our simulations provide a detailed view of key steps in GSDMDNT-induced plasma membrane pore formation, including sublytic pores that explain nonselective ion flux during early pyroptosis.
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Affiliation(s)
- Stefan L Schaefer
- Department of Theoretical Biophysics, Max Planck Institute of BiophysicsFrankfurt am MainGermany
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of BiophysicsFrankfurt am MainGermany
- Institute of Biophysics, Goethe University FrankfurtFrankfurt am MainGermany
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18
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Korn V, Pluhackova K. Not sorcery after all: Roles of multiple charged residues in membrane insertion of gasdermin-A3. Front Cell Dev Biol 2022; 10:958957. [PMID: 36120563 PMCID: PMC9479151 DOI: 10.3389/fcell.2022.958957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/26/2022] [Indexed: 11/16/2022] Open
Abstract
Gasdermins execute programmatory cell death, known as pyroptosis, by forming medium-sized membrane pores. Recently, the molecular structure of those pores as well as the diversity in their shape and size have been revealed by cryoTEM and atomic force microscopy, respectively. Even though a growth of smaller to larger oligomers and reshaping from slits to rings could be documented, the initiation of the gasdermin pore formation remains a mystery. In one hypothesis, gasdermin monomers insert into membranes before associating into oligomeric pores. In the other hypothesis, gasdermin oligomers preassemble on the membrane surface prior to membrane insertion. Here, by studying the behavior of monomeric membrane-inserted gasdermin-A3 (GSDMA3), we unveil that a monomeric gasdermin prefers the membrane-adsorbed over the membrane-inserted state. Our results thus support the hypothesis of oligomers preassembling on the membrane surface before membrane penetration. At the same time, our simulations of small membrane-inserted arcs of GSDMA3 suggest that the inserting oligomer can be small and does not have to comprise a full ring of approximately 26–30 subunits. Moreover, our simulations have revealed an astonishingly large impact of salt-bridge formation and protein surroundings on the transmembrane passage of charged residues, reducing the energetic cost by up to 53% as compared to their free forms. The here observed free energy barrier of mere 5.6 kcal/mol for the membrane insertion of monomeric GSDMA3 explains the surprising ability of gasdermins to spontaneously self-insert into cellular membranes.
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