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Berezin AE, Berezin AA. Extracellular vesicles in heart failure. Adv Clin Chem 2024; 119:1-32. [PMID: 38514208 DOI: 10.1016/bs.acc.2024.02.001] [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] [Indexed: 03/23/2024]
Abstract
Physiologically, extracellular vesicles (EVs) have been implicated as crucial mediators of immune response, cell homeostasis, angiogenesis, cell differentiation and growth, and tissue repair. In heart failure (HF) they may act as regulators of cardiac remodeling, microvascular inflammation, micro environmental changes, tissue fibrosis, atherosclerosis, neovascularization of plaques, endothelial dysfunction, thrombosis, and reciprocal heart-remote organ interaction. The chapter summaries the nomenclature, isolation, detection of EVs, their biologic role and function physiologically as well as in the pathogenesis of HF. Current challenges to the utilization of EVs as diagnostic and predictive biomarkers in HF are also discussed.
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Affiliation(s)
- Alexander E Berezin
- Department of Internal Medicine II, Division of Cardiology, Paracelsus Medical University Salzburg, Salzburg, Austria.
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2
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The choanoflagellate pore-forming lectin SaroL-1 punches holes in cancer cells by targeting the tumor-related glycosphingolipid Gb3. Commun Biol 2022; 5:954. [PMID: 36097056 PMCID: PMC9468336 DOI: 10.1038/s42003-022-03869-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/22/2022] [Indexed: 11/15/2022] Open
Abstract
Choanoflagellates are primitive protozoa used as models for animal evolution. They express a large variety of multi-domain proteins contributing to adhesion and cell communication, thereby providing a rich repertoire of molecules for biotechnology. Adhesion often involves proteins adopting a β-trefoil fold with carbohydrate-binding properties therefore classified as lectins. Sequence database screening with a dedicated method resulted in TrefLec, a database of 44714 β-trefoil candidate lectins across 4497 species. TrefLec was searched for original domain combinations, which led to single out SaroL-1 in the choanoflagellate Salpingoeca rosetta, that contains both β-trefoil and aerolysin-like pore-forming domains. Recombinant SaroL-1 is shown to bind galactose and derivatives, with a stronger affinity for cancer-related α-galactosylated epitopes such as the glycosphingolipid Gb3, when embedded in giant unilamellar vesicles or cell membranes. Crystal structures of complexes with Gb3 trisaccharide and GalNAc provided the basis for building a model of the oligomeric pore. Finally, recognition of the αGal epitope on glycolipids required for hemolysis of rabbit erythrocytes suggests that toxicity on cancer cells is achieved through carbohydrate-dependent pore-formation. A curated lectin database, structural characterization, and in vitro assays show that choanoflagellate lectin SaroL-1 binds to cancer-related α-galactosylated epitopes and can be toxic to cancer cells through a carbohydrate-dependent pore-formation mechanism.
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Lata K, Singh M, Chatterjee S, Chattopadhyay K. Membrane Dynamics and Remodelling in Response to the Action of the Membrane-Damaging Pore-Forming Toxins. J Membr Biol 2022; 255:161-173. [PMID: 35305136 DOI: 10.1007/s00232-022-00227-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/02/2022] [Indexed: 12/11/2022]
Abstract
Pore-forming protein toxins (PFTs) represent a diverse class of membrane-damaging proteins that are produced by a wide variety of organisms. PFT-mediated membrane perforation is largely governed by the chemical composition and the physical properties of the plasma membranes. The interaction between the PFTs with the target membranes is critical for the initiation of the pore-formation process, and can lead to discrete membrane reorganization events that further aids in the process of pore-formation. Punching holes on the plasma membranes by the PFTs interferes with the cellular homeostasis by disrupting the ion-balance inside the cells that in turn can turn on multiple signalling cascades required to restore membrane integrity and cellular homeostasis. In this review, we discuss the physicochemical attributes of the plasma membranes associated with the pore-formation processes by the PFTs, and the subsequent membrane remodelling events that may start off the membrane-repair mechanisms.
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Affiliation(s)
- Kusum Lata
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, 140306, India
| | - Mahendra Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, 140306, India
| | - Shamaita Chatterjee
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, 140306, India
| | - Kausik Chattopadhyay
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli, Mohali, Punjab, 140306, India.
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4
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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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5
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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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6
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Aden S, Snoj T, Anderluh G. The use of giant unilamellar vesicles to study functional properties of pore-forming toxins. Methods Enzymol 2021; 649:219-251. [PMID: 33712188 DOI: 10.1016/bs.mie.2021.01.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pore-forming toxins (PFTs) act upon lipid membranes and appropriate model systems are of great importance in researching these proteins. Giant unilamellar vesicles (GUVs) are an excellent model membrane system to study interactions between lipids and proteins. Their main advantage is the size comparable to cells, which means that GUVs can be observed directly under the light microscope. Many PFTs properties can be studied by using GUVs, such as binding specificity, membrane reorganization upon protein binding and oligomerization, pore properties and mechanism of pore formation. GUVs also represent a good model for biotechnological approaches, e.g., in applications in synthetic biology and medicine. Each research area has its own demands for GUVs properties, so several different approaches for GUVs preparations have been developed and will be discussed in this chapter.
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Affiliation(s)
- Saša Aden
- Department for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Tina Snoj
- Department for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia
| | - Gregor Anderluh
- Department for Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Ljubljana, Slovenia.
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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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8
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Keb G, Fields KA. An Ancient Molecular Arms Race: Chlamydia vs. Membrane Attack Complex/Perforin (MACPF) Domain Proteins. Front Immunol 2020; 11:1490. [PMID: 32760406 PMCID: PMC7371996 DOI: 10.3389/fimmu.2020.01490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/08/2020] [Indexed: 12/16/2022] Open
Abstract
Dynamic interactions that govern the balance between host and pathogen determine the outcome of infection and are shaped by evolutionary pressures. Eukaryotic hosts have evolved elaborate and formidable defense mechanisms that provide the basis for innate and adaptive immunity. Proteins containing a membrane attack complex/Perforin (MACPF) domain represent an important class of immune effectors. These pore-forming proteins induce cell killing by targeting microbial or host membranes. Intracellular bacteria can be shielded from MACPF-mediated killing, and Chlamydia spp. represent a successful paradigm of obligate intracellular parasitism. Ancestors of present-day Chlamydia likely originated at evolutionary times that correlated with or preceded many host defense pathways. We discuss the current knowledge regarding how chlamydiae interact with the MACPF proteins Complement C9, Perforin-1, and Perforin-2. Current evidence indicates a degree of resistance by Chlamydia to MACPF effector mechanisms. In fact, chlamydiae have acquired and adapted their own MACPF-domain protein to facilitate infection.
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Affiliation(s)
- Gabrielle Keb
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
| | - Kenneth A Fields
- Department of Microbiology, Immunology & Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, United States
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9
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Sordo-Bahamonde C, Lorenzo-Herrero S, Payer ÁR, Gonzalez S, López-Soto A. Mechanisms of Apoptosis Resistance to NK Cell-Mediated Cytotoxicity in Cancer. Int J Mol Sci 2020; 21:ijms21103726. [PMID: 32466293 PMCID: PMC7279491 DOI: 10.3390/ijms21103726] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/20/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022] Open
Abstract
Natural killer (NK) cells are major contributors to immunosurveillance and control of tumor development by inducing apoptosis of malignant cells. Among the main mechanisms involved in NK cell-mediated cytotoxicity, the death receptor pathway and the release of granules containing perforin/granzymes stand out due to their efficacy in eliminating tumor cells. However, accumulated evidence suggest a profound immune suppression in the context of tumor progression affecting effector cells, such as NK cells, leading to decreased cytotoxicity. This diminished capability, together with the development of resistance to apoptosis by cancer cells, favor the loss of immunogenicity and promote immunosuppression, thus partially inducing NK cell-mediated killing resistance. Altered expression patterns of pro- and anti-apoptotic proteins along with genetic background comprise the main mechanisms of resistance to NK cell-related apoptosis. Herein, we summarize the main effector cytotoxic mechanisms against tumor cells, as well as the major resistance strategies acquired by tumor cells that hamper the extrinsic and intrinsic apoptotic pathways related to NK cell-mediated killing.
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Affiliation(s)
- Christian Sordo-Bahamonde
- Department of Functional Biology, Immunology, University of Oviedo, 33006 Oviedo, Spain; (S.L.-H.); (S.G.)
- Instituto Universitario de Oncología del Principado de Asturias, IUOPA, 33006 Oviedo, Spain;
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Correspondence: (C.S.-B.); (A.L.-S.)
| | - Seila Lorenzo-Herrero
- Department of Functional Biology, Immunology, University of Oviedo, 33006 Oviedo, Spain; (S.L.-H.); (S.G.)
- Instituto Universitario de Oncología del Principado de Asturias, IUOPA, 33006 Oviedo, Spain;
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Ángel R. Payer
- Instituto Universitario de Oncología del Principado de Asturias, IUOPA, 33006 Oviedo, Spain;
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Department of Hematology, Hospital Universitario Central de Asturias (HUCA), 33011 Oviedo, Spain
| | - Segundo Gonzalez
- Department of Functional Biology, Immunology, University of Oviedo, 33006 Oviedo, Spain; (S.L.-H.); (S.G.)
- Instituto Universitario de Oncología del Principado de Asturias, IUOPA, 33006 Oviedo, Spain;
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
| | - Alejandro López-Soto
- Instituto Universitario de Oncología del Principado de Asturias, IUOPA, 33006 Oviedo, Spain;
- Instituto de Investigación Biosanitaria del Principado de Asturias (ISPA), 33011 Oviedo, Spain
- Department of Biochemistry and Molecular Biology, University of Oviedo, 33006 Oviedo, Spain
- Correspondence: (C.S.-B.); (A.L.-S.)
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10
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Arribas Perez M, Moriones OH, Bastús NG, Puntes V, Nelson A, Beales PA. Mechanomodulation of Lipid Membranes by Weakly Aggregating Silver Nanoparticles. Biochemistry 2019; 58:4761-4773. [DOI: 10.1021/acs.biochem.9b00390] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marcos Arribas Perez
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
| | - Oscar H. Moriones
- Institut Català de Nanociència y Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- Universitat Autonòma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - Neus G. Bastús
- Institut Català de Nanociència y Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra, Barcelona, Spain
| | - Victor Puntes
- Institut Català de Nanociència y Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- Universitat Autonòma de Barcelona (UAB), Campus UAB, 08193 Bellaterra, Barcelona, Spain
- Vall d’Hebron Institut de Recerca (VHIR), 08035 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Andrew Nelson
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Paul A. Beales
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
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11
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Ali Doosti B, Pezeshkian W, Bruhn DS, Ipsen JH, Khandelia H, Jeffries GDM, Lobovkina T. Membrane Tubulation in Lipid Vesicles Triggered by the Local Application of Calcium Ions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11010-11017. [PMID: 28910109 DOI: 10.1021/acs.langmuir.7b01461] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Experimental and theoretical studies on ion-lipid interactions predict that binding of calcium ions to cell membranes leads to macroscopic mechanical effects and membrane remodeling. Herein, we provide experimental evidence that a point source of Ca2+ acting upon a negatively charged membrane generates spontaneous curvature and triggers the formation of tubular protrusions that point away from the ion source. This behavior is rationalized by strong binding of the divalent cations to the surface of the charged bilayer, which effectively neutralizes the surface charge density of outer leaflet of the bilayer. The mismatch in the surface charge density of the two leaflets leads to nonzero spontaneous curvature. We probe this mismatch through the use of molecular dynamics simulations and validate that calcium ion binding to a lipid membrane is sufficient to generate inward spontaneous curvature, bending the membrane. Additionally, we demonstrate that the formed tubular protrusions can be translated along the vesicle surface in a controlled manner by repositioning the site of localized Ca2+ exposure. The findings demonstrate lipid membrane remodeling in response to local chemical gradients and offer potential insights into the cell membrane behavior under conditions of varying calcium ion concentrations.
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Affiliation(s)
- Baharan Ali Doosti
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
| | - Weria Pezeshkian
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Dennis S Bruhn
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - John H Ipsen
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Himanshu Khandelia
- Center for Biomembrane Physics (MEMPHYS), Department of Physics, Chemistry and Pharmacy (FKF), University of Southern Denmark , Campusvej 55, 5230 Odense M, Denmark
| | - Gavin D M Jeffries
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
| | - Tatsiana Lobovkina
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Gothenburg, Sweden
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12
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Ni T, Gilbert RJC. Repurposing a pore: highly conserved perforin-like proteins with alternative mechanisms. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160212. [PMID: 28630152 PMCID: PMC5483515 DOI: 10.1098/rstb.2016.0212] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2017] [Indexed: 12/02/2022] Open
Abstract
Pore-forming proteins play critical roles in pathogenic attack and immunological defence. The membrane attack complex/perforin (MACPF) group of homologues represents, with cholesterol-dependent cytolysins, the largest family of such proteins. In this review, we begin by describing briefly the structure of MACPF proteins, outlining their common mechanism of pore formation. We subsequently discuss some examples of MACPF proteins likely implicated in pore formation or other membrane-remodelling processes. Finally, we focus on astrotactin and bone morphogenetic protein and retinoic acid-induced neural-specific proteins, highly conserved MACPF family members involved in developmental processes, which have not been well studied to date or observed to form a pore-and which data suggest may act by alternative mechanisms.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Tao Ni
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Robert J C Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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13
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Naneh O, Zavec AB, Pahovnik D, Žagar E, Gilbert RJ, Križaj I, Anderluh G. An optimized protocol for expression and purification of murine perforin in insect cells. J Immunol Methods 2015. [DOI: 10.1016/j.jim.2015.07.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Kumar A, Baycin-Hizal D, Wolozny D, Pedersen LE, Lewis NE, Heffner K, Chaerkady R, Cole RN, Shiloach J, Zhang H, Bowen MA, Betenbaugh MJ. Elucidation of the CHO Super-Ome (CHO-SO) by Proteoinformatics. J Proteome Res 2015; 14:4687-703. [PMID: 26418914 DOI: 10.1021/acs.jproteome.5b00588] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chinese hamster ovary (CHO) cells are the preferred host cell line for manufacturing a variety of complex biotherapeutic drugs including monoclonal antibodies. We performed a proteomics and bioinformatics analysis on the spent medium from adherent CHO cells. Supernatant from CHO-K1 culture was collected and subjected to in-solution digestion followed by LC/LC-MS/MS analysis, which allowed the identification of 3281 different host cell proteins (HCPs). To functionally categorize them, we applied multiple bioinformatics tools to the proteins identified in our study including SignalP, TargetP, SecretomeP, TMHMM, WoLF PSORT, and Phobius. This analysis provided information on the presence of signal peptides, transmembrane domains, and cellular localization and showed that both secreted and intracellular proteins were constituents of the supernatant. Identified proteins were shown to be localized to the secretory pathway including ones playing roles in cell growth, proliferation, and folding as well as those involved in protein degradation and removal. After combining proteins predicted to be secreted or having a signal peptide, we identified 1015 proteins, which we termed as CHO supernatant-ome (CHO-SO), or superome. As a part of this effort, we created a publically accessible web-based tool called GO-CHO to functionally categorize proteins found in CHO-SO and identify enriched molecular functions, biological processes, and cellular components. We also used a tool to evaluate the immunogenicity potential of high-abundance HCPs. Among enriched functions were catalytic activity and structural constituents of the cytoskeleton. Various transport related biological processes, such as vesicle mediated transport, were found to be highly enriched. Extracellular space and vesicular exosome associated proteins were found to be the most enriched cellular components. The superome also contained proteins secreted from both classical and nonclassical secretory pathways. The work and database described in our study will enable the CHO community to rapidly identify high-abundance HCPs in their cultures and therefore help assess process and purification methods used in the production of biologic drugs.
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Affiliation(s)
- Amit Kumar
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States.,Biotechnology Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases , National Institute of Health, Building 14A, Bethesda, Maryland 20892, United States
| | - Deniz Baycin-Hizal
- Antibody Discovery and Protein Engineering, MedImmune LLC , 1 MedImmune Way, Gaithersburg, Maryland 20878, United States
| | - Daniel Wolozny
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Lasse Ebdrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark , DK-2970 Hørsholm, Denmark
| | - Nathan E Lewis
- Department of Biology, Brigham Young University , Provo, Utah 84602, United States.,Department of Pediatrics, University of California , San Diego, California 92093, United States
| | - Kelley Heffner
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
| | - Raghothama Chaerkady
- Institute of Basic Biomedical Sciences, Mass Spectrometry and Proteomics Facility, Johns Hopkins University School of Medicine , 733 North Broadway Street, Baltimore, Maryland 21205, United States
| | - Robert N Cole
- Institute of Basic Biomedical Sciences, Mass Spectrometry and Proteomics Facility, Johns Hopkins University School of Medicine , 733 North Broadway Street, Baltimore, Maryland 21205, United States
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases , National Institute of Health, Building 14A, Bethesda, Maryland 20892, United States
| | - Hui Zhang
- Department of Pathology, Johns Hopkins School of Medicine , 400 North Broadway Street, Baltimore, Maryland 21287, United States
| | - Michael A Bowen
- Antibody Discovery and Protein Engineering, MedImmune LLC , 1 MedImmune Way, Gaithersburg, Maryland 20878, United States
| | - Michael J Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University , Baltimore, Maryland 21218, United States
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15
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Perforin oligomers form arcs in cellular membranes: a locus for intracellular delivery of granzymes. Cell Death Differ 2014; 22:74-85. [PMID: 25146929 DOI: 10.1038/cdd.2014.110] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 07/01/2014] [Accepted: 07/03/2014] [Indexed: 01/28/2023] Open
Abstract
Perforin-mediated cytotoxicity is an essential host defense, in which defects contribute to tumor development and pathogenic disorders including autoimmunity and autoinflammation. How perforin (PFN) facilitates intracellular delivery of pro-apoptotic and inflammatory granzymes across the bilayer of targets remains unresolved. Here we show that cellular susceptibility to granzyme B (GzmB) correlates with rapid PFN-induced phosphatidylserine externalization, suggesting that pores are formed at a protein-lipid interface by incomplete membrane oligomers (or arcs). Supporting a role for these oligomers in protease delivery, an anti-PFN antibody (pf-80) suppresses necrosis but increases phosphatidylserine flip-flop and GzmB-induced apoptosis. As shown by atomic force microscopy on planar bilayers and deep-etch electron microscopy on mammalian cells, pf-80 increases the proportion of arcs which correlates with the presence of smaller electrical conductances, while large cylindrical pores decline. PFN appears to form arc structures on target membranes that serve as minimally disrupting conduits for GzmB translocation. The role of these arcs in PFN-mediated pathology warrants evaluation where they may serve as novel therapeutic targets.
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Zanetti M, Maniglio D, Fasoli C, Pola M, Borga E, Corradi C, Dalla Serra M, Iannotta S, Motta A, Toccoli T. A New Cells-Compatible Microfluidic Device for Single Channel Recordings. ELECTROANAL 2014. [DOI: 10.1002/elan.201400152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Li J, Figueira SK, Vrazo ACA, Binkowski BF, Butler BL, Tabata Y, Filipovich A, Jordan MB, Risma KA. Real-time detection of CTL function reveals distinct patterns of caspase activation mediated by Fas versus granzyme B. THE JOURNAL OF IMMUNOLOGY 2014; 193:519-28. [PMID: 24928990 DOI: 10.4049/jimmunol.1301668] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of caspase-mediated apoptosis is reported to be a hallmark of both granzyme B- and Fas-mediated pathways of killing by CTLs; however, the kinetics of caspase activation remain undefined owing to an inability to monitor target cell-specific apoptosis in real time. We have overcome this limitation by developing a novel biosensor assay that detects continuous, protease-specific activity in target cells. Biosensors were engineered from a circularly permuted luciferase, linked internally by either caspase 3/7 or granzyme B/caspase 8 cleavage sites, thus allowing activation upon proteolytic cleavage by the respective proteases. Coincubation of murine CTLs with target cells expressing either type of biosensor led to a robust luminescent signal within minutes of cell contact. The signal was modulated by the strength of TCR signaling, the ratio of CTL/target cells, and the type of biosensor used. Additionally, the luciferase signal at 30 min correlated with target cell death, as measured by a (51)Cr-release assay. The rate of caspase 3/7 biosensor activation was unexpectedly rapid following granzyme B- compared with Fas-mediated signal induction in murine CTLs; the latter appeared gradually after a 90-min delay in perforin- or granzyme B-deficient CTLs. Remarkably, the Fas-dependent, caspase 3/7 biosensor signal induced by perforin-deficient human CTLs was also detectable after a 90-min delay when measured by redirected killing. Thus, we have used a novel, real-time assay to demonstrate the distinct pattern of caspase activation induced by granzyme B versus Fas in human and murine CTLs.
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Affiliation(s)
- Jinzhu Li
- Division of Allergy/Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Sarah K Figueira
- Division of Allergy/Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Alexandra C A Vrazo
- Division of Allergy/Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | | | | | - Yasuhiro Tabata
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Alexandra Filipovich
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267; and
| | - Michael B Jordan
- Division of Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267; and Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229
| | - Kimberly A Risma
- Division of Allergy/Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267; and
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18
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Abstract
Pneumolysin is a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming proteins that are produced as water-soluble monomers or dimers, bind to target membranes and oligomerize into large ring-shaped assemblies comprising approximately 40 subunits and approximately 30 nm across. This pre-pore assembly then refolds to punch a large hole in the lipid bilayer. However, in addition to forming large pores, pneumolysin and other CDCs form smaller lesions characterized by low electrical conductance. Owing to the observation of arc-like (rather than full-ring) oligomers by electron microscopy, it has been hypothesized that smaller oligomers explain smaller functional pores. To investigate whether this is the case, we performed cryo-electron tomography of pneumolysin oligomers on model lipid membranes. We then used sub-tomogram classification and averaging to determine representative membrane-bound low-resolution structures and identified pre-pores versus pores by the presence of membrane within the oligomeric curve. We found pre-pore and pore forms of both complete (ring) and incomplete (arc) oligomers and conclude that arc-shaped oligomeric assemblies of pneumolysin can form pores. As the CDCs are evolutionarily related to the membrane attack complex/perforin family of proteins, which also form variably sized pores, our findings are of relevance to that class of proteins as well.
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Affiliation(s)
- Andreas F-P Sonnen
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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19
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Hermann E, Bleicken S, Subburaj Y, García-Sáez AJ. Automated analysis of giant unilamellar vesicles using circular Hough transformation. ACTA ACUST UNITED AC 2014; 30:1747-54. [PMID: 24554630 DOI: 10.1093/bioinformatics/btu102] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
MOTIVATION In order to obtain statistically relevant results, the study of membrane effects at the single-vesicle level requires the analysis of several hundreds of giant unilamellar vesicles (GUVs), which becomes a very time-consuming task if carried out manually. Complete and user-friendly software for fast and bias-free automated analysis has not been reported yet. RESULTS We developed a framework for the automated detection, tracking and analysis of individual GUVs on digital microscopy images. Our tool is suited to quantify protein binding to membranes as well as several aspects of membrane permeabilization on single vesicles. We demonstrate the applicability of the approach by comparing alternative activation methods for Bax, a pore-forming protein involved in mitochondrial permeabilization during apoptosis. AVAILABILITY AND IMPLEMENTATION The complete software is implemented in MATLAB (The MathWorks, Inc., USA) and available as a standalone as well as the full source code at http://www.ifib.uni-tuebingen.de/research/garcia-saez/guv-software.html.
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Affiliation(s)
- Eduard Hermann
- Max-Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart and Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany
| | - Stephanie Bleicken
- Max-Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart and Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany
| | - Yamunadevi Subburaj
- Max-Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart and Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany
| | - Ana J García-Sáez
- Max-Planck Institute for Intelligent Systems, Heisenbergstr. 3, 70569 Stuttgart and Interfaculty Institute for Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, 72076 Tübingen, Germany
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20
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Senior MJ, Wallace MI. Fluorescence imaging of MACPF/CDC proteins: new techniques and their application. Subcell Biochem 2014; 80:293-319. [PMID: 24798018 DOI: 10.1007/978-94-017-8881-6_15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Structural and biochemical investigations have helped illuminate many of the important details of MACPF/CDC pore formation. However, conventional techniques are limited in their ability to tackle many of the remaining key questions, and new biophysical techniques might provide the means to improve our understanding. Here we attempt to identify the properties of MACPF/CDC proteins that warrant further study, and explore how new developments in fluorescence imaging are able to probe these properties.
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Affiliation(s)
- Michael J Senior
- Department of Chemistry, Oxford University, 12 Mansfield Rd, Oxford, OX1 3TA, UK
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21
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Abstract
The complement system is an intricate network of serum proteins that mediates humoral innate immunity through an amplification cascade that ultimately leads to recruitment of inflammatory cells or opsonisation or killing of pathogens. One effector arm of this network is the terminal pathway of complement, which leads to the formation of the membrane attack complex (MAC) composed of complement components C5b, C6, C7, C8 and C9. Upon formation of C5 convertases via the classical or alternative pathways of complement activation, C5b is generated from C5 by proteolytic cleavage, nucleating a series of association and polymerisation reactions of the MAC-constituting complement components that culminate in pore formation of pathogenic membranes. Recent structures of MAC components and homologous proteins significantly increased our understanding of oligomerisation, membrane association and integration, shedding light onto the molecular mechanism of this important branch of the innate immune system.
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22
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Abstract
The cell membrane is crucial for protection of the cell from its environment. MACPF/CDC proteins are a large superfamily known to be essential for bacterial pathogenesis and proper functioning of the immune system. The three most studied groups of MACPF/CDC proteins are cholesterol-dependent cytolysins from bacteria, the membrane attack complex of complement and human perforin. Their primary function is to form transmembrane pores in target cell membranes. The common mechanism of action comprises water-soluble monomeric proteins binding to the host cell membrane, oligomerization, and formation of a functional pore. This causes a disturbance in gradients of ions and other molecules across the membrane and can lead to cell death. Cells react to this form of attack in a complex manner. Responses can be general, like removing the perforated part of the membrane, or more specific, in many cases depending on binding of proteins to specific receptors to trigger various signalling cascades.
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23
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Abstract
Chlamydiae are obligate intracellular bacterial parasites that infect a wide range of metazoan hosts. Some Chlamydia species are important causes of chronic inflammatory diseases of the ocular, genital and respiratory tracts in humans. Genes located in a variable region of chlamydial genomes termed the plasticity zone are known to be key determinants of pathogenic diversity. The plasticity zone protein CT153, present only in select species, contains a membrane attack complex/perforin (MACPF) domain, which may mediate chlamydial interactions with the host cell. CT153 is present throughout the C. trachomatis developmental cycle and is processed into polypeptides that interact with membranes differently than does the parent protein. Chlamydiae interact extensively with membranes from the time of invasion until they eventually exit host cells, so numerous roles for a MACPF protein in pathogenesis of these pathogens are conceivable. Here, we present an overview of what is known about CT153 and highlight potential roles of a MACPF family protein in a group of pathogens whose intracellular development is marked by a series of interactions with host cell membranes and organelles. Finally, we identify new strategies for identifying CT153 functions made feasible by the recent development of a basic toolset for genetic manipulation of chlamydiae.
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Affiliation(s)
- Lacey D Taylor
- Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Disease, National Institutes of Health, 903 S. 4th Street, Hamilton, MT 59840, USA,
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Thiery J, Lieberman J. Perforin: a key pore-forming protein for immune control of viruses and cancer. Subcell Biochem 2014; 80:197-220. [PMID: 24798013 DOI: 10.1007/978-94-017-8881-6_10] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Perforin (PFN) is the key pore-forming molecule in the cytotoxic granules of immune killer cells. Expressed only in killer cells, PFN is the rate-limiting molecule for cytotoxic function, delivering the death-inducing granule serine proteases (granzymes) into target cells marked for immune elimination. In this chapter we describe our current understanding of how PFN accomplishes this task. We discuss where PFN is expressed and how its expression is regulated, the biogenesis and storage of PFN in killer cells and how they are protected from potential damage, how it is released, how it delivers Granzymes into target cells and the consequences of PFN deficiency.
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Affiliation(s)
- Jerome Thiery
- INSERM U753, University Paris Sud and Gustave Roussy Cancer Campus, Villejuif, France,
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25
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Gilbert R. Structural features of cholesterol dependent cytolysins and comparison to other MACPF-domain containing proteins. Subcell Biochem 2014; 80:47-62. [PMID: 24798007 DOI: 10.1007/978-94-017-8881-6_4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Five different cholesterol-dependent cytolysins (CDCs) have now had their atomic structures solved. Here their structures are compared and shown to vary less in the C-terminal region than they do in their N-terminal MACPF/CDC homology region. The most variable region of the C-terminal domain is the undecapeptide, which is observed in two clusters of conformations, and comparison of this domain with the C2 domain of perforin shows that the two structures have a common ancestor. Structural studies of CDC pre-pore and pore oligomers by cryo-electron microscopy and atomic force microscopy have revealed much about their mechanism of action. Understanding the activity of CDCs has required a combination of structural, biophysical and functional assays but current models of pore formation still require development to account for variable functional pore size.
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Affiliation(s)
- Robert Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK,
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26
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Ota K, Leonardi A, Mikelj M, Skočaj M, Wohlschlager T, Künzler M, Aebi M, Narat M, Križaj I, Anderluh G, Sepčić K, Maček P. Membrane cholesterol and sphingomyelin, and ostreolysin A are obligatory for pore-formation by a MACPF/CDC-like pore-forming protein, pleurotolysin B. Biochimie 2013; 95:1855-64. [DOI: 10.1016/j.biochi.2013.06.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/12/2013] [Indexed: 12/16/2022]
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27
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Gilbert RJC, Mikelj M, Dalla Serra M, Froelich CJ, Anderluh G. Effects of MACPF/CDC proteins on lipid membranes. Cell Mol Life Sci 2013; 70:2083-98. [PMID: 22983385 PMCID: PMC11114033 DOI: 10.1007/s00018-012-1153-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 12/15/2022]
Abstract
Recent work on the MACPF/CDC superfamily of pore-forming proteins has focused on the structural analysis of monomers and pore-forming oligomeric complexes. We set the family of proteins in context and highlight aspects of their function which the direct and exclusive equation of oligomers with pores fails to explain. Starting with a description of the distribution of MACPF/CDC proteins across the domains of life, we proceed to show how their evolutionary relationships can be understood on the basis of their structural homology and re-evaluate models for pore formation by perforin, in particular. We furthermore highlight data showing the role of incomplete oligomeric rings (arcs) in pore formation and how this can explain small pores generated by oligomers of proteins belonging to the family. We set this in the context of cell biological and biophysical data on the proteins' function and discuss how this helps in the development of an understanding of how they act in processes such as apicomplexan parasites gliding through cells and exiting from cells.
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Affiliation(s)
- Robert J. C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN UK
| | - Miha Mikelj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Mauro Dalla Serra
- National Research Council, Institute of Biophysics and Bruno Kessler Foundation, via alla Cascata 56/C, 38123 Trento, Italy
| | - Christopher J. Froelich
- Department of Medicine, NorthShore University HealthSystem Research Institute, Evanston, IL 60201 USA
| | - Gregor Anderluh
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
- National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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28
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Mikelj M, Praper T, Demič R, Hodnik V, Turk T, Anderluh G. Electroformation of giant unilamellar vesicles from erythrocyte membranes under low-salt conditions. Anal Biochem 2013; 435:174-80. [DOI: 10.1016/j.ab.2013.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 12/24/2012] [Accepted: 01/02/2013] [Indexed: 01/10/2023]
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29
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Perforin forms transient pores on the target cell plasma membrane to facilitate rapid access of granzymes during killer cell attack. Blood 2013; 121:2659-68. [PMID: 23377437 DOI: 10.1182/blood-2012-07-446146] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cytotoxic lymphocytes serve a key role in immune homeostasis by eliminating virus-infected and transformed target cells through the perforin-dependent delivery of proapoptotic granzymes. However, the mechanism of granzyme entry into cells remains unresolved. Using biochemical approaches combined with time-lapse microscopy of human primary cytotoxic lymphocytes engaging their respective targets, we defined the time course of perforin pore formation in the context of the physiological immune synapse. We show that, on recognition of targets, calcium influx into the lymphocyte led to perforin exocytosis and target cell permeabilization in as little as 30 seconds. Within the synaptic cleft, target cell permeabilization by perforin resulted in the rapid diffusion of extracellular milieu-derived granzymes. Repair of these pores was initiated within 20 seconds and was completed within 80 seconds, thus limiting granzyme diffusion. Remarkably, even such a short time frame was sufficient for the delivery of lethal amounts of granzymes into the target cell. Rapid initiation of apoptosis was evident from caspase-dependent target cell rounding within 2 minutes of perforin permeabilization. This study defines the final sequence of events controlling cytotoxic lymphocyte immune defense, in which perforin pores assemble on the target cell plasma membrane, ensuring efficient delivery of lethal granzymes.
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30
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Krzewski K, Coligan JE. Human NK cell lytic granules and regulation of their exocytosis. Front Immunol 2012; 3:335. [PMID: 23162553 PMCID: PMC3494098 DOI: 10.3389/fimmu.2012.00335] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 10/22/2012] [Indexed: 12/16/2022] Open
Abstract
Natural killer (NK) cells form a subset of lymphocytes that play a key role in immuno-surveillance and host defense against cancer and viral infections. They recognize stressed cells through a variety of germline-encoded activating cell surface receptors and utilize their cytotoxic ability to eliminate abnormal cells. Killing of target cells is a complex, multi-stage process that concludes in the directed secretion of lytic granules, containing perforin and granzymes, at the immunological synapse. Upon delivery to a target cell, perforin mediates generation of pores in membranes of target cells, allowing granzymes to access target cell cytoplasm and induce apoptosis. Therefore, lytic granules of NK cells are indispensable for normal NK cell cytolytic function. Indeed, defects in lytic granule secretion lead or are related to serious and often fatal diseases, such as familial hemophagocytic lymphohistiocytosis (FHL) type 2–5 or Griscelli syndrome type 2. A number of reports highlight the role of several proteins involved in lytic granule release and NK cell-mediated killing of tumor cells. This review focuses on lytic granules of human NK cells and the advancements in understanding the mechanisms controlling their exocytosis.
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Affiliation(s)
- Konrad Krzewski
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health Rockville, MD, USA
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31
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Lopez JA, Brennan AJ, Whisstock JC, Voskoboinik I, Trapani JA. Protecting a serial killer: pathways for perforin trafficking and self-defence ensure sequential target cell death. Trends Immunol 2012; 33:406-12. [PMID: 22608996 DOI: 10.1016/j.it.2012.04.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 03/14/2012] [Accepted: 04/02/2012] [Indexed: 11/28/2022]
Abstract
Considerable progress has been made in understanding how cytotoxic lymphocytes use the highly toxic pore-forming protein perforin to eliminate dangerous cells, while remaining refractory to lysis. At least two mechanisms jointly preserve the killer cell: the C-terminal residues of perforin dictate its rapid export from the endoplasmic reticulum (ER), whose milieu otherwise favours pore formation; perforin is then stored in secretory granules whose acidity prevent its oligomerisation. Following exocytosis, perforin delivers the proapoptotic protease, granzyme B, into the target cell by disrupting its plasma membrane. Although the precise mechanism of perforin/granzyme synergy remains controversial, the recently defined crystal structure of the perforin monomer and cryo-electron microscopy (EM) of the entire pore suggest that passive transmembrane granzyme diffusion is the dominant proapoptotic mechanism.
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Affiliation(s)
- Jamie A Lopez
- Peter MacCallum Cancer Centre, East Melbourne, 3002, Victoria, Australia
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