151
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Flügel M, Becker A, Gartemann KH, Eichenlaub R. Analysis of the interaction of Clavibacter michiganensis subsp. michiganensis with its host plant tomato by genome-wide expression profiling. J Biotechnol 2012; 160:42-54. [PMID: 22326627 DOI: 10.1016/j.jbiotec.2012.01.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 01/12/2012] [Accepted: 01/24/2012] [Indexed: 11/26/2022]
Abstract
Genome-wide expression profiles of the phytopathogenic actinomycete Clavibacter michiganensis subsp. michiganensis (Cmm) strain NCPPB382 were analyzed using a 70mer oligonucleotide microarray. Cmm causes bacterial wilt and canker of tomato, a systemic disease leading to substantial economic losses worldwide. Global gene expression was monitored in vitro after long- and short-term incubation with tomato homogenate to simulate conditions in planta and in vivo ten days after inoculation of tomatoes. Surprisingly, both in the presence of tomato homogenate and in planta known virulence genes (celA, chpC, ppaA/C) were down-regulated indicating that the encoded extracellular enzymes are dispensable in late infection stages where plant tissue has already been heavily destroyed. In contrast, some genes of the tomA-region which are involved in sugar metabolism showed an enhanced RNA-level after permanent growth in supplemented medium. Therefore, these genes may be important for utilization of plant derived nutrients. In the plant Cmm exhibited an expression profile completely different from that in vitro. Especially, the strong expression of genes of the wco-cluster (extracellular polysaccharide II), 10 genes encoding surface or pilus assembly proteins, and CMM_2382, coding for a putative perforin suggest a possible role of these genes in the plant-pathogenic interaction.
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Affiliation(s)
- Monika Flügel
- Lehrstuhl für Gentechnologie/Mikrobiologie, Fakultät für Biologie, Universität Bielefeld, Universitätsstraße 25, Bielefeld, Germany
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152
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Aleshin AE, Schraufstatter IU, Stec B, Bankston LA, Liddington RC, DiScipio RG. Structure of complement C6 suggests a mechanism for initiation and unidirectional, sequential assembly of membrane attack complex (MAC). J Biol Chem 2012; 287:10210-10222. [PMID: 22267737 DOI: 10.1074/jbc.m111.327809] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The complement membrane attack complex (MAC) is formed by the sequential assembly of C5b with four homologous proteins as follows: one copy each of C6, C7, and C8 and 12-14 copies of C9. Together these form a lytic pore in bacterial membranes. C6 through C9 comprise a MAC-perforin domain flanked by 4-9 "auxiliary" domains. Here, we report the crystal structure of C6, the first and longest of the pore proteins to be recruited by C5b. Comparisons with the structures of the C8αβγ heterodimer and perforin show that the central domain of C6 adopts a "closed" (perforin-like) state that is distinct from the "open" conformations in C8. We further show that C6, C8α, and C8β contain three homologous subdomains ("upper," "lower," and "regulatory") related by rotations about two hinge points. In C6, the regulatory segment includes four auxiliary domains that stabilize the closed conformation, inhibiting release of membrane-inserting elements. In C8β, rotation of the regulatory segment is linked to an opening of the central β-sheet of its clockwise partner, C8α. Based on these observations, we propose a model for initiation and unidirectional propagation of the MAC in which the auxiliary domains play key roles: in the assembly of the C5b-8 initiation complex; in driving and regulating the opening of the β-sheet of the MAC-performin domain of each new recruit as it adds to the growing pore; and in stabilizing the final pore. Our model of the assembled pore resembles those of the cholesterol-dependent cytolysins but is distinct from that recently proposed for perforin.
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Affiliation(s)
- Alexander E Aleshin
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | | | - Boguslaw Stec
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Laurie A Bankston
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and
| | - Robert C Liddington
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037 and.
| | - Richard G DiScipio
- Torrey Pines Institute for Molecular Studies, San Diego, California 92121
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153
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Structural basis for membrane targeting by the MVB12-associated β-prism domain of the human ESCRT-I MVB12 subunit. Proc Natl Acad Sci U S A 2012; 109:1901-6. [PMID: 22232651 DOI: 10.1073/pnas.1117597109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
MVB12-associated β-prism (MABP) domains are predicted to occur in a diverse set of membrane-associated bacterial and eukaryotic proteins, but their existence, structure, and biochemical properties have not been characterized experimentally. Here, we find that the MABP domains of the MVB12A and B subunits of ESCRT-I are functional modules that bind in vitro to liposomes containing acidic lipids depending on negative charge density. The MABP domain is capable of autonomously localizing to subcellular puncta and to the plasma membrane. The 1.3-Å atomic resolution crystal structure of the MVB12B MABP domain reveals a β-prism fold, a hydrophobic membrane-anchoring loop, and an electropositive phosphoinositide-binding patch. The basic patch is open, which explains how it senses negative charge density but lacks stereoselectivity. These observations show how ESCRT-I could act as a coincidence detector for acidic phospholipids and protein ligands, enabling it to function both in protein transport at endosomes and in cytokinesis and viral budding at the plasma membrane.
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154
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Abstract
Infection with Listeria monocytogenes shows an early stage of lymphocyte apoptosis. This is an obligatory stage the extent of which depends on infective dose. Lymphocyte apoptosis occurs early and is rapidly superseded, yet it has a strong biological consequence. The immunological effect of lymphocyte apoptosis following infection is increased susceptibility to L. monocytogenes infection due, in part, to upregulation of IL-10 on macrophages and DC. Lymphocyte apoptosis is dependent on bacterial expression of the pore-forming toxin listeriolysin O (LLO). Also, purified LLO can lead to the induction of death pathways similar to infection, demonstrating that it is a killer agent generated by L. monocytogenes. Signaling through the type I interferon receptor potentiates cell death induced by the bacteria or LLO. Infection with L. monocytogenes also causes death of phagocytic cells, the nature and significance of which is not clear at present. Infection with L. monocytogenes is a tractable model to examine pathogen-induced cell death pathways and their possible immunological consequences in multiple cell types following infection.
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155
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Spicer JA, Huttunen KM, Miller CK, Denny WA, Ciccone A, Browne KA, Trapani JA. Inhibition of the pore-forming protein perforin by a series of aryl-substituted isobenzofuran-1(3H)-ones. Bioorg Med Chem 2011; 20:1319-36. [PMID: 22244072 DOI: 10.1016/j.bmc.2011.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Revised: 12/05/2011] [Accepted: 12/07/2011] [Indexed: 12/28/2022]
Abstract
An aryl-substituted isobenzofuran-1(3H)-one lead compound was identified from a high throughput screen designed to find inhibitors of the lymphocyte pore-forming protein perforin. A series of analogs were then designed and prepared, exploring structure-activity relationships through variation of 2-thioxoimidazolidin-4-one and furan subunits on an isobenzofuranone core. The ability of the resulting compounds to inhibit the lytic activity of both isolated perforin protein and perforin delivered in situ by intact KHYG-1 natural killer effector cells was determined. Several compounds showed excellent activity at concentrations that were non-toxic to the killer cells. This series represents a significant improvement on previous classes of compounds, being substantially more potent and largely retaining activity in the presence of serum.
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Affiliation(s)
- Julie A Spicer
- Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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156
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Perforin activity at membranes leads to invaginations and vesicle formation. Proc Natl Acad Sci U S A 2011; 108:21016-21. [PMID: 22173634 DOI: 10.1073/pnas.1107473108] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The cytotoxic cell granule secretory pathway is essential for immune defence. How the pore-forming protein perforin (PFN) facilitates the cytosolic delivery of granule-associated proteases (granzymes) remains enigmatic. Here we show that PFN is able to induce invaginations and formation of complete internal vesicles in giant unilamellar vesicles. Formation of internal vesicles depends on native PFN and calcium and antibody labeling shows the localization of PFN at the invaginations. This vesiculation is recapitulated in large unilamellar vesicles and in this case PFN oligomers can be seen associated with the necks of the invaginations. Capacitance measurements show PFN is able to increase a planar lipid membrane surface area in the absence of pore formation, in agreement with the ability to induce invaginations. Finally, addition of PFN to Jurkat cells causes the formation of internal vesicles prior to pore formation. PFN is capable of triggering an endocytosis-like event in addition to pore formation, suggesting a new paradigm for its role in delivering apoptosis-inducing granzymes into target cells.
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157
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Stivala A, Wybrow M, Wirth A, Whisstock JC, Stuckey PJ. Automatic generation of protein structure cartoons with Pro-origami. Bioinformatics 2011; 27:3315-6. [PMID: 21994221 DOI: 10.1093/bioinformatics/btr575] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
SUMMARY Protein topology diagrams are 2D representations of protein structure that are particularly useful in understanding and analysing complex protein folds. Generating such diagrams presents a major problem in graph drawing, with automatic approaches often resulting in errors or uninterpretable results. Here we apply a breakthrough in diagram layout to protein topology cartoons, providing clear, accurate, interactive and editable diagrams, which are also an interface to a structural search method. AVAILABILITY Pro-origami is available via a web server at http://munk.csse.unimelb.edu.au/pro-origami CONTACT a.stivala@pgrad.unimelb.edu.au; pjs@csse.unimelb.edu.au.
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Affiliation(s)
- Alex Stivala
- Department of Computer Science and Software Engineering, The University of Melbourne Parkville Campus, Victoria 3010, Australia.
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158
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Estévez-Calvar N, Romero A, Figueras A, Novoa B. Involvement of pore-forming molecules in immune defense and development of the Mediterranean mussel (Mytilus galloprovincialis). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2011; 35:1017-1031. [PMID: 21530583 DOI: 10.1016/j.dci.2011.03.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 03/25/2011] [Accepted: 03/27/2011] [Indexed: 05/30/2023]
Abstract
The membrane attack complex and perforin (MACPF) superfamily is one of the largest families of pore-forming molecules. Although MACPF proteins are able to destruct invading microbes, several MACPF proteins play roles in embryonic development, neural migration or tumor suppression. We describe two apextrin-like proteins (ApelB and ApelP) and one MACPF-domain-containing protein (Macp) in Mytilus galloprovincialis. The two apextrin-like proteins did not present any conserved domain. The Macp protein contained the membrane/attack complex domain and its signature motif. Gene expression during larval development was analyzed by RT-PCR. There was a stage-specific up-regulation of the three proteins, suggesting that they play a role in development. Apextrin-like proteins were highly expressed at blastula and trochophore stage, whereas Macp was expressed at veliger stage. RT-PCR revealed up-regulation of the three genes in tissues and hemocytes from adults treated with bacteria and pathogen-associated molecular patterns, suggesting that they may be involved in the immune response.
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Affiliation(s)
- Noelia Estévez-Calvar
- Instituto de Investigaciones Marinas. Consejo Superior de Investigaciones Científicas (CSIC). Eduardo Cabello, Vigo, Spain
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159
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Equal force recovery in dysferlin-deficient and wild-type muscles following saponin exposure. J Biomed Biotechnol 2011; 2011:235216. [PMID: 21941430 PMCID: PMC3175419 DOI: 10.1155/2011/235216] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 06/24/2011] [Accepted: 07/19/2011] [Indexed: 11/29/2022] Open
Abstract
Dysferlin plays an important role in repairing membrane damage elicited by laser irradiation, and dysferlin deficiency causes muscular dystrophy and associated cardiomyopathy. Proteins such as perforin, complement component C9, and bacteria-derived cytolysins, as well as the natural detergent saponin, can form large pores on the cell membrane via complexation with cholesterol. However, it is not clear whether dysferlin plays a role in repairing membrane damage induced by pore-forming reagents. In this study, we observed that dysferlin-deficient muscles recovered the tetanic force production to the same extent as their WT counterparts following a 5-min saponin exposure (50 μg/mL). Interestingly, the slow soleus muscles recovered significantly better than the fast extensor digitorum longus (EDL) muscles. Our data suggest that dysferlin is unlikely involved in repairing saponin-induced membrane damage and that the slow muscle is more efficient than the fast muscle in repairing such damage.
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160
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Abstract
How do killer cells restrain perforin, the most potent toxin known to biologists, at its point of synthesis in the endoplasmic reticulum, where conditions are ideal for its activation? In this issue of Immunity, Brennan et al. (2011) study its trafficking, offering insights into protective mechanisms.
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Affiliation(s)
- Christopher Froelich
- NorthShore University HealthSystems Research Institute, Evanston, IL 60201, USA.
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161
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Kafsack BFC, Carruthers VB. Apicomplexan perforin-like proteins. Commun Integr Biol 2011; 3:18-23. [PMID: 20539776 DOI: 10.4161/cib.3.1.9794] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 08/12/2009] [Indexed: 12/13/2022] Open
Abstract
Numerous perforin-like proteins are encoded in the genomes of apicomplexan parasites, where they are expressed in various life-cycle stages and play critical roles in pathogenesis and lifecycle progression. These ApiPLPs are characterized by the presence of a MACPF domain, responsible for pore-formation in target membranes in a number of systems, including many bacterial pathogens and effector cells of the immune response. ApiPLP MACPF domains maintain the critical structural elements but are often present in new and intriguing domain arrangements. Recent work in Toxoplasma and Plasmodium has shown that ApiPLPs are important for breaching membranes during parasite egress and cell traversal. Here we present an overview of this important protein family from a structural, functional and phylogenetic perspective across the Apicomplexa.
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Affiliation(s)
- Björn F C Kafsack
- Department of Microbiology and Immunology; University of Michigan; Ann Arbor, MI USA
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162
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Lyons DM, Huttunen KM, Browne KA, Ciccone A, Trapani JA, Denny WA, Spicer JA. Inhibition of the cellular function of perforin by 1-amino-2,4-dicyanopyrido[1,2-a]benzimidazoles. Bioorg Med Chem 2011; 19:4091-100. [DOI: 10.1016/j.bmc.2011.05.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/03/2011] [Accepted: 05/09/2011] [Indexed: 11/27/2022]
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163
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Brennan AJ, Chia J, Browne KA, Ciccone A, Ellis S, Lopez JA, Susanto O, Verschoor S, Yagita H, Whisstock JC, Trapani JA, Voskoboinik I. Protection from endogenous perforin: glycans and the C terminus regulate exocytic trafficking in cytotoxic lymphocytes. Immunity 2011; 34:879-92. [PMID: 21658975 DOI: 10.1016/j.immuni.2011.04.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 01/18/2011] [Accepted: 04/07/2011] [Indexed: 11/15/2022]
Abstract
Cytotoxic lymphocyte-mediated apoptosis is dependent on the delivery of perforin to secretory granules and its ability to form calcium-dependent pores in the target cell after granule exocytosis. It is unclear how cytotoxic lymphocytes synthesize and store perforin without incurring damage or death. We discovered that the extreme C terminus of perforin was essential for rapid trafficking from the endoplasmic reticulum to the Golgi compartment. Substitution of the C-terminal tryptophan residue resulted in retention of perforin in the ER followed by calcium-dependent toxic activity that eliminated host cells. We also found that N-linked glycosylation of perforin was critical for transport from the Golgi to secretory granules. Overall, an intact C terminus and N-linked glycosylation provide accurate and efficient export of perforin from the endoplasmic reticulum to the secretory granules and are critical for cytotoxic lymphocyte survival.
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Affiliation(s)
- Amelia J Brennan
- Cancer Immunology Program, Peter MacCallum Cancer Centre, Melbourne, 3002, Australia
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164
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Szczesny P, Iacovache I, Muszewska A, Ginalski K, van der Goot FG, Grynberg M. Extending the aerolysin family: from bacteria to vertebrates. PLoS One 2011; 6:e20349. [PMID: 21687664 PMCID: PMC3110756 DOI: 10.1371/journal.pone.0020349] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 04/29/2011] [Indexed: 11/18/2022] Open
Abstract
A number of bacterial virulence factors have been observed to adopt structures similar to that of aerolysin, the principal toxin of Aeromonas species. However, a comprehensive description of architecture and structure of the aerolysin-like superfamily has not been determined. In this study, we define a more compact aerolysin-like domain--or aerolysin fold--and show that this domain is far more widely spread than anticipated since it can be found throughout kingdoms. The aerolysin-fold could be found in very diverse domain and functional contexts, although a toxic function could often be assigned. Due to this diversity, the borders of the superfamily could not be set on a sequence level. As a border-defining member, we therefore chose pXO2-60--a protein from the pathogenic pXO2 plasmid of Bacillus anthracis. This fascinating protein, which harbors a unique ubiquitin-like fold domain at the C-terminus of the aerolysin-domain, nicely illustrates the diversity of the superfamily. Its putative role in the virulence of B. anthracis and its three dimensional model are discussed.
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Affiliation(s)
- Pawel Szczesny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Experimental Plant Biology, University of Warsaw, Warsaw, Poland
| | - Ioan Iacovache
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Ginalski
- Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Warsaw, Poland
| | - F. Gisou van der Goot
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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165
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Stewart SE, D'Angelo ME, Bird PI. Intercellular communication via the endo-lysosomal system: translocation of granzymes through membrane barriers. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2011; 1824:59-67. [PMID: 21683168 DOI: 10.1016/j.bbapap.2011.05.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 11/24/2022]
Abstract
Cytotoxic lymphocytes (CLs) are responsible for the clearance of virally infected or neoplastic cells. CLs possess specialised lysosome-related organelles called granules which contain the granzyme family of serine proteases and perforin. Granzymes may induce apoptosis in the target cell when delivered by the pore forming protein, perforin. Here we follow the perforin-granzyme pathway from synthesis and storage in the granule, to exocytosis and finally delivery into the target cell. This review focuses on the controversial subject of perforin-mediated translocation of granzymes into the target cell cytoplasm. It remains unclear whether this occurs at the cell surface with granzymes moving through a perforin pore in the plasma membrane, or if it involves internalisation of perforin and granzymes and subsequent release from an endocytic compartment. The latter mechanism would represent an example of cross talk between the endo-lysosomal pathways of individual cells. This article is part of a Special Issue entitled: Proteolysis 50 years after the discovery of lysosome.
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Affiliation(s)
- Sarah E Stewart
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
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166
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Lovelace LL, Cooper CL, Sodetz JM, Lebioda L. Structure of human C8 protein provides mechanistic insight into membrane pore formation by complement. J Biol Chem 2011; 286:17585-92. [PMID: 21454577 PMCID: PMC3093833 DOI: 10.1074/jbc.m111.219766] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/23/2011] [Indexed: 11/06/2022] Open
Abstract
C8 is one of five complement proteins that assemble on bacterial membranes to form the lethal pore-like "membrane attack complex" (MAC) of complement. The MAC consists of one C5b, C6, C7, and C8 and 12-18 molecules of C9. C8 is composed of three genetically distinct subunits, C8α, C8β, and C8γ. The C6, C7, C8α, C8β, and C9 proteins are homologous and together comprise the MAC family of proteins. All contain N- and C-terminal modules and a central 40-kDa membrane attack complex perforin (MACPF) domain that has a key role in forming the MAC pore. Here, we report the 2.5 Å resolution crystal structure of human C8 purified from blood. This is the first structure of a MAC family member and of a human MACPF-containing protein. The structure shows the modules in C8α and C8β are located on the periphery of C8 and not likely to interact with the target membrane. The C8γ subunit, a member of the lipocalin family of proteins that bind and transport small lipophilic molecules, shows no occupancy of its putative ligand-binding site. C8α and C8β are related by a rotation of ∼22° with only a small translational component along the rotation axis. Evolutionary arguments suggest the geometry of binding between these two subunits is similar to the arrangement of C9 molecules within the MAC pore. This leads to a model of the MAC that explains how C8-C9 and C9-C9 interactions could facilitate refolding and insertion of putative MACPF transmembrane β-hairpins to form a circular pore.
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Affiliation(s)
- Leslie L. Lovelace
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Christopher L. Cooper
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - James M. Sodetz
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Lukasz Lebioda
- From the Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
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167
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Toxoplasma gondii: Protective immunity against experimental toxoplasmosis induced by a DNA vaccine encoding the perforin-like protein 1. Exp Parasitol 2011; 128:38-43. [DOI: 10.1016/j.exppara.2011.02.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 01/10/2011] [Accepted: 02/01/2011] [Indexed: 01/28/2023]
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168
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Gonzalez MR, Bischofberger M, Frêche B, Ho S, Parton RG, van der Goot FG. Pore-forming toxins induce multiple cellular responses promoting survival. Cell Microbiol 2011; 13:1026-43. [PMID: 21518219 DOI: 10.1111/j.1462-5822.2011.01600.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Pore-forming toxins (PFTs) are secreted proteins that contribute to the virulence of a great variety of bacterial pathogens. They inflict one of the more disastrous damages a target cell can be exposed to: disruption of plasma membrane integrity. Since this is an ancient form of attack, which bears similarities to mechanical membrane damage, cells have evolved response pathways to these perturbations. Here, it is reported that PFTs trigger very diverse yet specific response pathways. Many are triggered by the decrease in cytoplasmic potassium, which thus emerges as a central regulator. Upon plasma membrane damage, cells activate signalling pathways aimed at restoring plasma membrane integrity and ion homeostasis. Interestingly these pathways do not require protein synthesis. Cells also trigger signalling cascades that allow them to enter a quiescent-like state, where minimal energy is consumed while waiting for plasma membrane damage to be repaired. More specifically, protein synthesis is arrested, cytosolic constituents are recycled by autophagy and energy is stored in lipid droplets.
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Affiliation(s)
- Manuel R Gonzalez
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Faculty of Life Sciences, Lausanne, Switzerland
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169
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Wickham SE, Hotze EM, Farrand AJ, Polekhina G, Nero TL, Tomlinson S, Parker MW, Tweten RK. Mapping the intermedilysin-human CD59 receptor interface reveals a deep correspondence with the binding site on CD59 for complement binding proteins C8alpha and C9. J Biol Chem 2011; 286:20952-62. [PMID: 21507937 DOI: 10.1074/jbc.m111.237446] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD59 is a glycosylphosphatidylinositol-anchored protein that inhibits the assembly of the terminal complement membrane attack complex (MAC) pore, whereas Streptococcus intermedius intermedilysin (ILY), a pore forming cholesterol-dependent cytolysin (CDC), specifically binds to human CD59 (hCD59) to initiate the formation of its pore. The identification of the residues of ILY and hCD59 that form their binding interface revealed a remarkably deep correspondence between the hCD59 binding site for ILY and that for the MAC proteins C8α and C9. ILY disengages from hCD59 during the prepore to pore transition, suggesting that loss of this interaction is necessary to accommodate specific structural changes associated with this transition. Consistent with this scenario, mutants of hCD59 or ILY that increased the affinity of this interaction decreased the cytolytic activity by slowing the transition of the prepore to pore but not the assembly of the prepore oligomer. A signature motif was also identified in the hCD59 binding CDCs that revealed a new hCD59-binding member of the CDC family. Although the binding site on hCD59 for ILY, C8α, and C9 exhibits significant homology, no similarity exists in their binding sites for hCD59. Hence, ILY and the MAC proteins interact with common amino acids of hCD59 but lack detectable conservation in their binding sites for hCD59.
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Affiliation(s)
- Stephanie E Wickham
- Department of Microbiology and Immunology, the University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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170
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He X, Zhang Y, Yu Z. An Mpeg (macrophage expressed gene) from the Pacific oyster Crassostrea gigas: molecular characterization and gene expression. FISH & SHELLFISH IMMUNOLOGY 2011; 30:870-876. [PMID: 21272653 DOI: 10.1016/j.fsi.2011.01.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Accepted: 01/14/2011] [Indexed: 05/30/2023]
Abstract
Mpegs (macrophage expressed genes) encode members of the MACPF (membrane-attack complex/perforin) protein superfamily that play essential roles in innate immunity. In the present study, a homolog of Mpeg1 was identified in Crassostrea gigas and designed Cg-Mpeg1. The complete cDNA of Cg-Mpeg1 is 2781 bp in length, containing an ORF of 2226 bp, which encodes a putative protein of 742 amino acids with a predicted 19-aa hydrophobic signal peptide, an MACPF domain, and a transmembrane domain. Phylogenetic analysis shows that Cg-Mpeg1 is similar to other mollusk MACPF proteins and might originate in an ancient ancestor gene before the divergence of protostomes and deuterostomes. Localization study revealed that Cg-Mpeg1 protein is found primarily in late endosomes. The MACPF domain from Cg-Mpeg1 exhibits significant antibacterial activity to both Gram-negative and positive bacteria. Furthermore, Real-time Quantitative PCR analysis showed that Cg-Mpeg1 is expressed in all tissues detected with highest expression in gill and gonads. Moreover, Mpeg1 mRNA levels are significantly up-regulated following infection with Vibrio alginolyticus. These results highlight that Cg-Mpeg1 plays an essential role in host defense and elimination of pathogens in C. gigas.
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Affiliation(s)
- Xiaocui He
- Key Laboratory of Marine Bio-resources Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
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171
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Niche of harmful alga Aureococcus anophagefferens revealed through ecogenomics. Proc Natl Acad Sci U S A 2011; 108:4352-7. [PMID: 21368207 DOI: 10.1073/pnas.1016106108] [Citation(s) in RCA: 167] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Harmful algal blooms (HABs) cause significant economic and ecological damage worldwide. Despite considerable efforts, a comprehensive understanding of the factors that promote these blooms has been lacking, because the biochemical pathways that facilitate their dominance relative to other phytoplankton within specific environments have not been identified. Here, biogeochemical measurements showed that the harmful alga Aureococcus anophagefferens outcompeted co-occurring phytoplankton in estuaries with elevated levels of dissolved organic matter and turbidity and low levels of dissolved inorganic nitrogen. We subsequently sequenced the genome of A. anophagefferens and compared its gene complement with those of six competing phytoplankton species identified through metaproteomics. Using an ecogenomic approach, we specifically focused on gene sets that may facilitate dominance within the environmental conditions present during blooms. A. anophagefferens possesses a larger genome (56 Mbp) and has more genes involved in light harvesting, organic carbon and nitrogen use, and encoding selenium- and metal-requiring enzymes than competing phytoplankton. Genes for the synthesis of microbial deterrents likely permit the proliferation of this species, with reduced mortality losses during blooms. Collectively, these findings suggest that anthropogenic activities resulting in elevated levels of turbidity, organic matter, and metals have opened a niche within coastal ecosystems that ideally suits the unique genetic capacity of A. anophagefferens and thus, has facilitated the proliferation of this and potentially other HABs.
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172
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Oloo EO, Yethon JA, Ochs MM, Carpick B, Oomen R. Structure-guided antigen engineering yields pneumolysin mutants suitable for vaccination against pneumococcal disease. J Biol Chem 2011; 286:12133-40. [PMID: 21296887 DOI: 10.1074/jbc.m110.191148] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pneumolysin (PLY) is a cholesterol-binding, pore-forming protein toxin. It is an important virulence factor of Streptococcus pneumoniae and a key vaccine target against pneumococcal disease. We report a systematic structure-driven approach that solves a long-standing problem for vaccine development in this field: detoxification of PLY with retention of its antigenic integrity. Using three conformational restraint techniques, we rationally designed variants of PLY that lack hemolytic activity and yet induce neutralizing antibodies against the wild-type toxin. These results represent a key milestone toward a broad-spectrum protein-based pneumococcal vaccine and illustrate the value of structural knowledge in formulating effective strategies for antigen optimization.
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Affiliation(s)
- Eliud O Oloo
- sanofi pasteur, Toronto, Ontario M2R 3T4, Canada.
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173
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Konjar S, Sutton VR, Hoves S, Repnik U, Yagita H, Reinheckel T, Peters C, Turk V, Turk B, Trapani JA, Kopitar-Jerala N. Human and mouse perforin are processed in part through cleavage by the lysosomal cysteine proteinase cathepsin L. Immunology 2011; 131:257-67. [PMID: 20497254 DOI: 10.1111/j.1365-2567.2010.03299.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The pore-forming protein perforin is synthesized as an inactive precursor in natural killer (NK) cells and cytotoxic T lymphocytes (CTLs), and becomes active when a short C-terminal peptide is cleaved within acidic lysosome-like cytotoxic granules. Although it was shown more than a decade ago that this cleavage is pH dependent and can be inhibited by the generic cysteine cathepsin inhibitor E-64d, no protease capable of processing the perforin C terminus has been identified. Neither is it known whether a single protease is responsible or the processing has inbuilt redundancy. Here, we show that incubation of human NK cells and primary antigen-restricted mouse CTLs with the cathepsin L (CatL) inhibitor L1 resulted in a marked inhibition of perforin-dependent target cell death and reduced perforin processing. In vitro, CatL preferentially cleaved a site on full-length recombinant perforin close to its C terminus. The NK cells of mice deficient in CatL showed a reduction but not a complete absence of processed perforin, indicating that cysteine proteases other than CatL are also able to process perforin. We conclude that granule-bound cathepsins are essential for processing perforin to its active form, and that CatL is an important, but not exclusive, participant in this process.
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Affiliation(s)
- Spela Konjar
- Department of Biochemistry, Molecular and Structural Biology, Jozef Stefan Institute, Ljubljana, Slovenia
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174
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Rynearson TA, Palenik B. Learning to read the oceans genomics of marine phytoplankton. ADVANCES IN MARINE BIOLOGY 2011; 60:1-39. [PMID: 21962749 DOI: 10.1016/b978-0-12-385529-9.00001-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The phytoplankton are key members of marine ecosystems, generating about half of global primary productivity, supporting valuable fisheries and regulating global biogeochemical cycles. Marine phytoplankton are phylogenetically diverse and are comprised of both prokaryotic and eukaryotic species. In the last decade, new insights have been gained into the ecology and evolution of these important organisms through whole genome sequencing projects and more recently, through both transcriptomics and targeted metagenomics approaches. Sequenced genomes of cyanobacteria are generally small, ranging in size from 1.8 to 9 million base pairs (Mbp). Eukaryotic genomes, in general, have a much larger size range and those that have been sequenced range from 12 to 57 Mbp. Whole genome sequencing projects have revealed key features of the evolutionary history of marine phytoplankton, their varied responses to environmental stress, their ability to scavenge and store nutrients and their unique ability to form elaborate cellular coverings. We have begun to learn how to read the 'language' of marine phytoplankton, as written in their DNA. Here, we review the ecological and evolutionary insights gained from whole genome sequencing projects, illustrate how these genomes are yielding information on marine natural products and informing nanotechnology as well as make suggestions for future directions in the field of marine phytoplankton genomics.
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Affiliation(s)
- Tatiana A Rynearson
- Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA.
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175
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Bubeck D, Roversi P, Donev R, Morgan BP, Llorca O, Lea SM. Structure of human complement C8, a precursor to membrane attack. J Mol Biol 2010; 405:325-30. [PMID: 21073882 PMCID: PMC3021121 DOI: 10.1016/j.jmb.2010.10.031] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 10/13/2010] [Accepted: 10/19/2010] [Indexed: 11/25/2022]
Abstract
Complement component C8 plays a pivotal role in the formation of the membrane attack complex (MAC), an important antibacterial immune effector. C8 initiates membrane penetration and coordinates MAC pore formation. High-resolution structures of C8 subunits have provided some insight into the function of the C8 heterotrimer; however, there is no structural information describing how the intersubunit organization facilitates MAC assembly. We have determined the structure of C8 by electron microscopy and fitted the C8α-MACPF (membrane attack complex/perforin)-C8γ co-crystal structure and a homology model for C8β-MACPF into the density. Here, we demonstrate that both the C8γ protrusion and the C8α-MACPF region that inserts into the membrane upon activation are accessible.
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Affiliation(s)
- Doryen Bubeck
- University of Oxford, Wellcome Trust Centre for Human Genetics, Oxford OX3 7BN, UK
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176
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The structural basis for membrane binding and pore formation by lymphocyte perforin. Nature 2010; 468:447-51. [PMID: 21037563 DOI: 10.1038/nature09518] [Citation(s) in RCA: 297] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 09/20/2010] [Indexed: 01/08/2023]
Abstract
Natural killer cells and cytotoxic T lymphocytes accomplish the critically important function of killing virus-infected and neoplastic cells. They do this by releasing the pore-forming protein perforin and granzyme proteases from cytoplasmic granules into the cleft formed between the abutting killer and target cell membranes. Perforin, a 67-kilodalton multidomain protein, oligomerizes to form pores that deliver the pro-apoptopic granzymes into the cytosol of the target cell. The importance of perforin is highlighted by the fatal consequences of congenital perforin deficiency, with more than 50 different perforin mutations linked to familial haemophagocytic lymphohistiocytosis (type 2 FHL). Here we elucidate the mechanism of perforin pore formation by determining the X-ray crystal structure of monomeric murine perforin, together with a cryo-electron microscopy reconstruction of the entire perforin pore. Perforin is a thin 'key-shaped' molecule, comprising an amino-terminal membrane attack complex perforin-like (MACPF)/cholesterol dependent cytolysin (CDC) domain followed by an epidermal growth factor (EGF) domain that, together with the extreme carboxy-terminal sequence, forms a central shelf-like structure. A C-terminal C2 domain mediates initial, Ca(2+)-dependent membrane binding. Most unexpectedly, however, electron microscopy reveals that the orientation of the perforin MACPF domain in the pore is inside-out relative to the subunit arrangement in CDCs. These data reveal remarkable flexibility in the mechanism of action of the conserved MACPF/CDC fold and provide new insights into how related immune defence molecules such as complement proteins assemble into pores.
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177
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Carton I, Brisson AR, Richter RP. Label-Free Detection of Clustering of Membrane-Bound Proteins. Anal Chem 2010; 82:9275-81. [DOI: 10.1021/ac102495q] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ixaskun Carton
- Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia−San Sebastian, Spain, Max-Planck-Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany, and Laboratory of Molecular Imaging and Nanobiotechnology, IECB, UMR-5248 CBMN, CNRS-University Bordeaux 1-ENITAB, Avenue des Facultés, 33402 Talence, France
| | - Alain R. Brisson
- Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia−San Sebastian, Spain, Max-Planck-Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany, and Laboratory of Molecular Imaging and Nanobiotechnology, IECB, UMR-5248 CBMN, CNRS-University Bordeaux 1-ENITAB, Avenue des Facultés, 33402 Talence, France
| | - Ralf P. Richter
- Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia−San Sebastian, Spain, Max-Planck-Institute for Metals Research, Heisenbergstrasse 3, 70569 Stuttgart, Germany, and Laboratory of Molecular Imaging and Nanobiotechnology, IECB, UMR-5248 CBMN, CNRS-University Bordeaux 1-ENITAB, Avenue des Facultés, 33402 Talence, France
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178
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Xu Q, Abdubek P, Astakhova T, Axelrod HL, Bakolitsa C, Cai X, Carlton D, Chen C, Chiu HJ, Clayton T, Das D, Deller MC, Duan L, Ellrott K, Farr CL, Feuerhelm J, Grant JC, Grzechnik A, Han GW, Jaroszewski L, Jin KK, Klock HE, Knuth MW, Kozbial P, Krishna SS, Kumar A, Lam WW, Marciano D, Miller MD, Morse AT, Nigoghossian E, Nopakun A, Okach L, Puckett C, Reyes R, Tien HJ, Trame CB, van den Bedem H, Weekes D, Wooten T, Yeh A, Zhou J, Hodgson KO, Wooley J, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA. Structure of a membrane-attack complex/perforin (MACPF) family protein from the human gut symbiont Bacteroides thetaiotaomicron. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1297-305. [PMID: 20944225 PMCID: PMC2954219 DOI: 10.1107/s1744309110023055] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 06/15/2010] [Indexed: 11/11/2022]
Abstract
Membrane-attack complex/perforin (MACPF) proteins are transmembrane pore-forming proteins that are important in both human immunity and the virulence of pathogens. Bacterial MACPFs are found in diverse bacterial species, including most human gut-associated Bacteroides species. The crystal structure of a bacterial MACPF-domain-containing protein BT_3439 (Bth-MACPF) from B. thetaiotaomicron, a predominant member of the mammalian intestinal microbiota, has been determined. Bth-MACPF contains a membrane-attack complex/perforin (MACPF) domain and two novel C-terminal domains that resemble ribonuclease H and interleukin 8, respectively. The entire protein adopts a flat crescent shape, characteristic of other MACPF proteins, that may be important for oligomerization. This Bth-MACPF structure provides new features and insights not observed in two previous MACPF structures. Genomic context analysis infers that Bth-MACPF may be involved in a novel protein-transport or nutrient-uptake system, suggesting an important role for these MACPF proteins, which were likely to have been inherited from eukaryotes via horizontal gene transfer, in the adaptation of commensal bacteria to the host environment.
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Affiliation(s)
- Qingping Xu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Polat Abdubek
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Tamara Astakhova
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Herbert L. Axelrod
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Constantina Bakolitsa
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Xiaohui Cai
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Dennis Carlton
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Connie Chen
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Hsiu-Ju Chiu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Thomas Clayton
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Debanu Das
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Marc C. Deller
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Lian Duan
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Kyle Ellrott
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Carol L. Farr
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Julie Feuerhelm
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Joanna C. Grant
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Anna Grzechnik
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Gye Won Han
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Lukasz Jaroszewski
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Kevin K. Jin
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Heath E. Klock
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Mark W. Knuth
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Piotr Kozbial
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - S. Sri Krishna
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Abhinav Kumar
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Winnie W. Lam
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - David Marciano
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Mitchell D. Miller
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Andrew T. Morse
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Edward Nigoghossian
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Amanda Nopakun
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Linda Okach
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Christina Puckett
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Ron Reyes
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Henry J. Tien
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Christine B. Trame
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Henry van den Bedem
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Dana Weekes
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Tiffany Wooten
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Andrew Yeh
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Jiadong Zhou
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
| | - Keith O. Hodgson
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Photon Science, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - John Wooley
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
| | - Marc-André Elsliger
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Ashley M. Deacon
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
| | - Adam Godzik
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Center for Research in Biological Systems, University of California, San Diego, La Jolla, CA, USA
- Program on Bioinformatics and Systems Biology, Sanford–Burnham Medical Research Institute, La Jolla, CA, USA
| | - Scott A. Lesley
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, San Diego, CA, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Ian A. Wilson
- Joint Center for Structural Genomics, http://www.jcsg.org, USA
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA, USA
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179
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Kondos SC, Hatfaludi T, Voskoboinik I, Trapani JA, Law RHP, Whisstock JC, Dunstone MA. The structure and function of mammalian membrane-attack complex/perforin-like proteins. ACTA ACUST UNITED AC 2010; 76:341-51. [PMID: 20860583 DOI: 10.1111/j.1399-0039.2010.01566.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The membrane-attack complex (MAC) of complement pathway and perforin (PF) are important tools deployed by the immune system to target pathogens. Both perforin and the C9 component of the MAC contain a common 'MACPF' domain and form pores in the cell membrane as part of their function. The MAC targets gram-negative bacteria and certain pathogenic parasites, while perforin, released by natural killer cells or cytotoxic T lymphocytes (CTLs), targets virus-infected and transformed host cells (1). Remarkably, recent structural studies show that the MACPF domain is homologous to the pore-forming portion of bacterial cholesterol-dependent cytolysins; these data have provided important insight into the mechanism of pore-forming MACPF proteins. In addition to their role in immunity, MACPF family members have been identified as animal venoms, factors required for pathogen migration across host cell membranes and factors that govern developmental processes such as embryonic patterning and neuronal guidance (2). While most MACPF proteins characterized to date either form pores or span lipid membranes, some do not (e.g. the C6 component of the MAC). A current challenge is thus to understand the role, pore forming or otherwise, of MACPF proteins in developmental biology. This review discusses structural and functional diversity of the mammalian MACPF proteins.
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Affiliation(s)
- S C Kondos
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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180
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Sutton VR, Trapani JA. Proteases in lymphocyte killer function: redundancy, polymorphism and questions remaining. Biol Chem 2010; 391:873-9. [DOI: 10.1515/bc.2010.088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractProteases of the serine and cysteine protease families are involved in many processes crucial to the lytic functions of cytotoxic T lymphocytes and natural killer cells. In this study we describe those functions and attempt to place them in the pathophysiological context of defence to pathogen invasion. In particular, we stress that the co-evolution of pathogens with the immune systems of higher organisms over evolutionary time has ensured that redundancy, flexibility and polymorphism of the proteases can be identified, both within the protease repertoire of a given species, and by comparing orthologous protease functions across species.
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181
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Pachlopnik Schmid J, Schmid JP, Côte M, Ménager MM, Burgess A, Nehme N, Ménasché G, Fischer A, de Saint Basile G. Inherited defects in lymphocyte cytotoxic activity. Immunol Rev 2010; 235:10-23. [PMID: 20536552 DOI: 10.1111/j.0105-2896.2010.00890.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The granule-dependent cytotoxic activity of lymphocytes plays a critical role in the defense against virally infected cells and tumor cells. The importance of this cytotoxic pathway in immune regulation is evidenced by the severe and often fatal condition, known as hemophagocytic lymphohistiocytic syndrome (HLH) that occurs in mice and humans with genetically determined impaired lymphocyte cytotoxic function. HLH manifests as the occurrence of uncontrolled activation of T lymphocytes and macrophages infiltrating multiple organs. In this review, we focus on recent advances in the characterization of effectors regulating the release of cytotoxic granules, and on the role of this cytotoxic pathway in lymphocyte homeostasis and immune surveillance. Analysis of the mechanisms leading to the occurrence of hemophagocytic syndrome designates gamma-interferon as an attractive therapeutic target to downregulate uncontrolled macrophage activation, which sustains clinical and biological features of HLH.
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Affiliation(s)
- Jana Pachlopnik Schmid
- Institut National de la Santé et de la Recherche Médicale (INSERM), U768, 75015 Paris, France
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182
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Abstract
Granzyme B (GzmB) is used by cytotoxic lymphocytes as a molecular weapon for the defense against virus-infected and malignantly transformed host cells. It belongs to a family of small serine proteases that are stored in secretory vesicles of killer cells. After secretion of these cytolytic granules during killer cell attack, GzmB is translocated into the cytosol of target cells with the help of the pore-forming protein perforin. GzmB has adopted similar protease specificity as caspase-8, and once delivered, it activates major executioner apoptosis pathways. Since GzmB is very effective in killing human tumor cell lines that are otherwise resistant against many cytotoxic drugs and since GzmB of human origin can be recombinantly expressed, its use as part of a 'magic bullet' in tumor therapy is a very tempting idea. In this review, we emphasize the peculiar characteristics of GzmB that make it suited for use as an effector domain in potential immunoconjugates. We discuss what is known about its uptake into target cells and the trials performed with GzmB-armed immunoconjugates, and we assess the prospects of its potential therapeutic value.
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Affiliation(s)
- Florian C Kurschus
- Institute of Molecular Medicine, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany
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183
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Voskoboinik I, Dunstone MA, Baran K, Whisstock JC, Trapani JA. Perforin: structure, function, and role in human immunopathology. Immunol Rev 2010; 235:35-54. [PMID: 20536554 DOI: 10.1111/j.0105-2896.2010.00896.x] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The secretory granule-mediated cell death pathway is the key mechanism for elimination of virus-infected and transformed target cells by cytotoxic lymphocytes. The formation of the immunological synapse between an effector and a target cell leads to exocytic trafficking of the secretory granules and the release of their contents, which include pro-apoptotic serine proteases, granzymes, and pore-forming perforin into the synapse. There, perforin polymerizes and forms a transmembrane pore that allows the delivery of granzymes into the cytosol, where they initiate various apoptotic death pathways. Unlike relatively redundant individual granzymes, functional perforin is absolutely essential for cytotoxic lymphocyte function and immune regulation in the host. Nevertheless, perforin is still the least studied and understood cytotoxic molecule in the immune system. In this review, we discuss the current state of affairs in the perforin field: the protein's structure and function as well as its role in immune-mediated diseases.
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Affiliation(s)
- Ilia Voskoboinik
- Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Vic. 8006, Australia
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184
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Mitchell CM, Hovis KM, Bavoil PM, Myers GSA, Carrasco JA, Timms P. Comparison of koala LPCoLN and human strains of Chlamydia pneumoniae highlights extended genetic diversity in the species. BMC Genomics 2010; 11:442. [PMID: 20646324 PMCID: PMC3091639 DOI: 10.1186/1471-2164-11-442] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 07/21/2010] [Indexed: 11/28/2022] Open
Abstract
Background Chlamydia pneumoniae is a widespread pathogen causing upper and lower respiratory tract infections in addition to a range of other diseases in humans and animals. Previous whole genome analyses have focused on four essentially clonal (> 99% identity) C. pneumoniae human genomes (AR39, CWL029, J138 and TW183), providing relatively little insight into strain diversity and evolution of this species. Results We performed individual gene-by-gene comparisons of the recently sequenced C. pneumoniae koala genome and four C. pneumoniae human genomes to identify species-specific genes, and more importantly, to gain an insight into the genetic diversity and evolution of the species. We selected genes dispersed throughout the chromosome, representing genes that were specific to C. pneumoniae, genes with a demonstrated role in chlamydial biology and/or pathogenicity (n = 49), genes encoding nucleotide salvage or amino acid biosynthesis proteins (n = 6), and extrachromosomal elements (9 plasmid and 2 bacteriophage genes). Conclusions We have identified strain-specific differences and targets for detection of C. pneumoniae isolates from both human and animal origin. Such characterisation is necessary for an improved understanding of disease transmission and intervention.
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Affiliation(s)
- Candice M Mitchell
- Faculty of Science and Technology, Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove, Queensland 4059, Australia
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185
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de Saint Basile G, Ménasché G, Fischer A. Molecular mechanisms of biogenesis and exocytosis of cytotoxic granules. Nat Rev Immunol 2010; 10:568-79. [PMID: 20634814 DOI: 10.1038/nri2803] [Citation(s) in RCA: 303] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cytotoxic T cells and natural killer cells are crucial for immune surveillance against virus-infected cells and tumour cells. Molecular studies of individuals with inherited defects that impair lymphocyte cytotoxic function have also highlighted the importance of cytotoxicity in the regulation and termination of immune responses. As discussed in this Review, characterization of these defects has contributed to our understanding of the key steps that are required for the maturation of cytotoxic granules and the secretion of their contents at the immunological synapse during target cell killing. This has revealed a marked similarity between cytotoxic granule exocytosis at the immunological synapse and synaptic vesicle exocytosis at the neurological synapse. We explore the possibility that comparison of these two kinetically and spatially regulated secretory pathways will provide clues to uncover additional effectors that regulate the cytotoxic function of lymphocytes.
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Affiliation(s)
- Geneviève de Saint Basile
- Institut National de la Santé et de la Recherche Médicale (INSERM), U768, Hôpital Necker Enfants Malades, 149 rue de Sèvres, 75015 Paris, France.
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186
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Abstract
Our web site (http://ekhidna.biocenter.helsinki.fi/dali_server) runs the Dali program for protein structure comparison. The web site consists of three parts: (i) the Dali server compares newly solved structures against structures in the Protein Data Bank (PDB), (ii) the Dali database allows browsing precomputed structural neighbourhoods and (iii) the pairwise comparison generates suboptimal alignments for a pair of structures. Each part has its own query form and a common format for the results page. The inputs are either PDB identifiers or novel structures uploaded by the user. The results pages are hyperlinked to aid interactive analysis. The web interface is simple and easy to use. The key purpose of interactive analysis is to check whether conserved residues line up in multiple structural alignments and how conserved residues and ligands cluster together in multiple structure superimpositions. In favourable cases, protein structure comparison can lead to evolutionary discoveries not detected by sequence analysis.
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Affiliation(s)
- Liisa Holm
- Institute of Biotechnology and Department of Biosciences, University of Helsinki, Helsinki, Finland.
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187
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de Souza RF, Aravind L. UMA and MABP domains throw light on receptor endocytosis and selection of endosomal cargoes. Bioinformatics 2010; 26:1477-80. [PMID: 20448139 PMCID: PMC2881412 DOI: 10.1093/bioinformatics/btq235] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Interactions of the ESCRT complexes are critical for endosomal trafficking. We identify two domains with potential significance for this process. The MABP domain present in metazoan ESCRT-I/MVB12 subunits, Crag, a regulator of protein sorting, and bacterial pore-forming proteins might mediate novel membrane interactions in trafficking. The UBAP1-MVB12-associated UMA domain found in MVB12 and UBAP1 defines a novel adaptor that might recruit diverse targets to ESCRT-I. Contact:aravind@ncbi.nlm.nih.gov Supplementary information:Supplementary data are available at ftp://ftp.ncbi.nih.gov/pub/aravind/UMA/MVB12.html.
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Affiliation(s)
- Robson F de Souza
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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188
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Abstract
Granzyme A (GzmA) is the most abundant serine protease in killer cell cytotoxic granules. GzmA activates a novel programed cell death pathway that begins in the mitochondrion, where cleavage of NDUFS3 in electron transport complex I disrupts mitochondrial metabolism and generates reactive oxygen species (ROS). ROS drives the endoplasmic reticulum-associated SET complex into the nucleus, where it activates single-stranded DNA damage. GzmA also targets other important nuclear proteins for degradation, including histones, the lamins that maintain the nuclear envelope, and several key DNA damage repair proteins (Ku70, PARP-1). Cells that are resistant to the caspases or GzmB by overexpressing bcl-2 family anti-apoptotic proteins or caspase or GzmB protease inhibitors are sensitive to GzmA. By activating multiple cell death pathways, killer cells provide better protection against a variety of intracellular pathogens and tumors. GzmA also has proinflammatory activity; it activates pro-interleukin-1beta and may also have other proinflammatory effects that remain to be elucidated.
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Affiliation(s)
- Judy Lieberman
- Immune Disease Institute and Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA.
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189
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Black SM, Schott ME, Batdorf BH, Benson BA, Rutherford MS, Levay-Young BK, Dalmasso AP. IL-4 induces protection of vascular endothelial cells against killing by complement and melittin through lipid biosynthesis. Eur J Immunol 2010; 40:803-12. [PMID: 20017192 DOI: 10.1002/eji.200939488] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have shown previously that cytokines IL-4 and IL-13 induce protection in porcine vascular endothelial cells (EC) against killing by the membrane attack complex (MAC) of human complement. This protection is intrinsic, not due to changes in complement regulatory proteins, and requires activation of Akt and sterol receptor element binding protein-1 (SREBP-1), which regulates fatty acid and phospholipid synthesis. Here we report that, compared to EC incubated in medium, IL-4-treated EC had a profound reduction in complement-mediated ATP loss and in killing assessed by vital dye uptake, but only a slight reduction in permeability disruption measured by calcein release. While controls exposed to complement lost mitochondrial membrane potential and subsequently died, protected EC maintained mitochondrial morphology and membrane potential, and remained alive. SREBP-1 and fatty acid synthase activation were required for protection and fatty acid and phospholipid synthesis, including cardiolipin, were increased after IL-4 stimulation, without increase in cholesterol content or cell proliferation. IL-4 also induced protection of EC from killing by the channel forming protein melittin, similar to protection observed for the MAC. We conclude that IL-4 induced activation of Akt/SREBP-1/lipid biosynthesis in EC, resulting in protection against MAC and melittin, in association with mitochondrial protection.
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Affiliation(s)
- Sylvester M Black
- Department of Surgery, Medical School, University of Minnesota, Minneapolis, MN 55455, USA
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190
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Abstract
Cellular apoptosis induced by T cells is mainly mediated by two pathways. One, granule exocytosis utilizes perforin/granzymes. The other involves signaling through death receptors of the TNF-alpha R super-family, especially FasL. Perforin plays a central role in apoptosis induced by granzymes. However, the mechanisms of perforin-mediated cytotoxicity are still not elucidated completely. Perforin is not only a pore-forming protein, but also performs multiple biological functions or perforin performs one biological function (cytolysis), but has multiple biological implications in the cellular immune responses, including regulation of proliferation of CD8+ CTLs.
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Affiliation(s)
- Fang Zhou
- Department of Neurology, 300 Jefferson Hospital for Neurosciences Building, Thomas Jefferson University, 900 Walnut Street, Philadelphia, PA 19107, USA. [corrected]
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191
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Biological characterization of Chlamydia trachomatis plasticity zone MACPF domain family protein CT153. Infect Immun 2010; 78:2691-9. [PMID: 20351143 DOI: 10.1128/iai.01455-09] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chlamydia trachomatis strains are obligate intracellular human pathogens that share near genomic synteny but have distinct infection and disease organotropisms. The genetic basis for differences in the pathogen-host relationship among chlamydial strains is linked to a variable region of chlamydial genomes, termed the plasticity zone (PZ). Two groups of PZ-encoded proteins, the membrane attack complex/perforin (MACPF) domain protein (CT153) and members of the phospholipase D-like (PLD) family, are related to proteins that modify membranes and lipids, but the functions of CT153 and the PZ PLDs (pzPLDs) are unknown. Here, we show that full-length CT153 (p91) was present in the elementary bodies (EBs) of 15 C. trachomatis reference strains. CT153 underwent a rapid infection-dependent proteolytic cleavage into polypeptides of 57 and 41 kDa that was independent of de novo chlamydial protein synthesis. Following productive infection, p91 was expressed during the mid-developmental cycle and was similarly processed into p57 and p41 fragments. Infected-cell fractionation studies showed that insoluble fractions contained p91, p57, and p41, whereas only p91 was found in the soluble fraction, indicating that unprocessed CT153 may be secreted. Finally, CT153 localized to a distinct population of reticulate bodies, some of which were in contact with the inclusion membrane.
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192
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Xu L, Huang B, Du H, Zhang XC, Xu J, Li X, Rao Z. Crystal structure of cytotoxin protein suilysin from Streptococcus suis. Protein Cell 2010; 1:96-105. [PMID: 21204001 DOI: 10.1007/s13238-010-0012-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/13/2009] [Indexed: 10/19/2022] Open
Abstract
Cholesterol-dependent cytolysins (CDC) are pore forming toxins. A prototype of the CDC family members is perfringolysin O (PFO), which directly binds to the cell membrane enriched in cholesterol, causing cell lysis. However, an exception of this general observation is intermedilysin (ILY) of Streptococcus intermedius, which requires human CD59 as a receptor in addition to cholesterol for its hemolytic activity. A possible explanation of this functional difference is the conformational variation between the C-terminal domains of the two toxins, particularly in the highly conserved undecapeptide termed tryptophan rich motif. Here, we present the crystal structure of suilysin, a CDC toxin from the infectious swine pathogen Streptococcus suis. Like PFO, suilysin does not require a host receptor for hemolytic activity; yet the crystal structure of suilysin exhibits a similar conformation in the tryptophan rich motif to ILY. This observation suggests that the current view of the structure-function relationship between CDC proteins and membrane association is far from complete.
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Affiliation(s)
- Lingfeng Xu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
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193
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Abstract
Cytotoxic lymphocytes (CLs) are the killer cells that destroy intracellular pathogen-infected and transformed cells, predominantly through the cytotoxic granule-mediated death pathway. Soluble cytotoxic granule components, including pore-forming perforin and pro-apoptotic serine proteases, granzymes, synergize to induce unscheduled apoptosis of the target cell. A complete loss of CL function results in an aggressive immunoregulatory disorder, familial hemophagocytic lymphohistiocytosis, whereas a partial loss of function seems to be a factor strongly predisposing to hematological malignancies. This review discusses the pathological manifestations of CL deficiencies due to impaired perforin function and describes novel aspects of perforin biology.
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194
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Abstract
The cholesterol-dependent cytolysins (CDCs) are part of a large family of pore-forming proteins that include the human proteins perforin and the complement membrane attack complex. The activity of all family members is focused on membranes, but the proteins are themselves involved in a diverse range of phenomena. An overview of some of these phenomena is provided here, along with an historical perspective of CDCs themselves and how our understanding of their mechanism of action has developed over the years. The way in which pore formation depends on specific characteristics of the membrane under attack as well as of the protein doing the attacking is emphasised. The cholesterol-dependent cytolysins (CDCs) have been the focus of a renewed keen research interest for over ten years now. Their importance has been even further enhanced by the homology now identified between them and the membrane attack complex/perforin (MACPF) family of proteins, which includes several components of the complement cascade as well as perforin itself. In this chapter I aim to provide an overview of our understanding of the interaction between CDCs and other members of what is now called the MACPF/CDC superfamily, with their target membranes. CDCs (also in the past known as thiol-activated toxins or cholesterol-binding toxins) were originally identified from four Gram-positive bacterial genera (Clostridium, Listeria, Bacillus and Streptococcus). Well-known examples include listeriolysin, perfringolysin, streptolysin and pneumoysin. Listeriolysin from L. monocytogenes is responsible for the escape of bacteria from the phagosome to colonise the cytoplasm and has been applied as a protein adjuvant in the development of vaccines against cancer and tuberculosis, for example. Perfringolysin from C. perfringens (Fig. 1A) has become perhaps the most studied CDC4 and has an important role in pathology associated with infection (gangrene). Streptolysin from S. pyogenes is another intensely studied CDC and has been applied widely in experimental permeabilisation of biological membranes. Pneumolysin is a major virulence determinant for S. pneumoniae, allowing bacterial invasion of tissues and mediating inflammation and the activation of the complement cascade. However, CDCs have now, for example, been identified in the bacteria Arcanobacterium pyogenes and Gardnerella vaginalis and there also appear to be homologues outside prokaryotes such as the sea anemone Metridium senile pore-forming toxin metridiolysin. The homology with the MACPF family was unknown until the first structures of the canonical fold of that family were solved, revealing the now characteristic MACPF/CDC fold of a twisted 3-sheet around which helices are clustered (Fig. 1A and D). Without any significant other sequence homology, the fold of this superfamily of pore-forming and membrane-binding proteins has been conserved by compensatory mutation around a handful of key conserved glycines. The glycines presumably act as critical hinges during the dramatic refolding that CDCs are known to undergo and which is presumably the selective advantage of this specific structure that has caused it to be conserved over such a vast evolutionary timescale. While not all MACPF domains are involved in pore formation-for example, C6 and C8beta--they are all apparently involved in action on membranes. The dramatic refolding undergone by CDCs is tightly coupled to their oligomerisation and results in the conversion of the helices hemming the core 3-sheet of the MACPF/CDC domain into a pair of beta-hairpins which in tandem and alongside those from other subunits within the oligomer insert into the membrane to create a pore (Fig. 1A-C). It is obviously the basic assumption that where nonCDC members of the superfamily-such as complement proteins and perforin-act on membranes they do so by a mechanism involving similar refolding.58 Even where a member of the MACPF/CDC superfamily is not known to form a pore, or has been shown not to-at least alone-the same conformational change could have other adaptive functions during activity on or at membranes. However, the bicomponent nature of some pore-forming toxins alerts us that showing an absence of activity for one pure protein does not mean that they do not contribute to pore formation quite directly, since that may require the presence of another MACPF/CDC family member or members from the same specific system. Complement acts by a combination of the C5b-8 complex of proteins preassembled on a target membrane recruiting C9 to form a lesion, which may be a complete ring of C9 associated with the C5b-8 or an arc-electron microscopy images show both possibilities.Perforin acts in concert with granzymes, to trigger apoptosis when delivered by cytotoxic cells at their targets (damaged, transformed and infected host cells). Incomplete rings are visible for perforin also and there are many unresolved issues concerning its mechanism and the dependence ofgranzymes on it for their delivery.
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Affiliation(s)
- Robert J C Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, UK.
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195
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Heuck AP, Moe PC, Johnson BB. The cholesterol-dependent cytolysin family of gram-positive bacterial toxins. Subcell Biochem 2010; 51:551-577. [PMID: 20213558 DOI: 10.1007/978-90-481-8622-8_20] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The cholesterol-dependent cytolysins (CDCs) are a family of beta-barrel pore-forming toxins secreted by Gram-positive bacteria. These toxins are produced as water-soluble monomeric proteins that after binding to the target cell oligomerize on the membrane surface forming a ring-like pre-pore complex, and finally insert a large beta-barrel into the membrane (about 250 A in diameter). Formation of such a large transmembrane structure requires multiple and coordinated conformational changes. The presence of cholesterol in the target membrane is absolutely required for pore-formation, and therefore it was long thought that cholesterol was the cellular receptor for these toxins. However, not all the CDCs require cholesterol for binding. Intermedilysin, secreted by Streptoccocus intermedius only binds to membranes containing a protein receptor, but forms pores only if the membrane contains sufficient cholesterol. In contrast, perfringolysin O, secreted by Clostridium perfringens, only binds to membranes containing substantial amounts of cholesterol. The mechanisms by which cholesterol regulates the cytolytic activity of the CDCs are not understood at the molecular level. The C-terminus of perfringolysin O is involved in cholesterol recognition, and changes in the conformation of the loops located at the distal tip of this domain affect the toxin-membrane interactions. At the same time, the distribution of cholesterol in the membrane can modulate toxin binding. Recent studies support the concept that there is a dynamic interplay between the cholesterol-binding domain of the CDCs and the excess of cholesterol molecules in the target membrane.
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Affiliation(s)
- Alejandro P Heuck
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA.
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196
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197
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Complement-mediated bacteriolysis after binding of specific antibodies to drug-resistant Pseudomonas aeruginosa: morphological changes observed by using a field emission scanning electron microscope. J Infect Chemother 2010; 16:383-7. [DOI: 10.1007/s10156-010-0074-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 04/27/2010] [Indexed: 11/26/2022]
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198
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Hoves S, Trapani JA, Voskoboinik I. The battlefield of perforin/granzyme cell death pathways. J Leukoc Biol 2009; 87:237-43. [DOI: 10.1189/jlb.0909608] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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199
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Abstract
Egress is a pivotal step in the life cycle of intracellular pathogens initiating the transition from an expiring host cell to a fresh target cell. While much attention has been focused on understanding cell invasion by intracellular pathogens, recent work is providing a new appreciation of mechanisms and therapeutic potential of microbial egress. This review highlights recent insight into cell egress by apicomplexan parasites and emerging contributions of membranolytic and proteolytic secretory products, along with host proteases. New findings suggest that Toxoplasma gondii secretes a pore-forming protein, TgPLP1, during egress that facilitates parasite escape from the cell by perforating the parasitophorous membrane. Also, in a cascade of proteolytic events, Plasmodium falciparum late-stage schizonts activate and secrete a subtilisin, PfSUB1, which processes enigmatic putative proteases called serine-repeat antigens that contribute to merozoite egress. A new report also suggests that calcium-activated host proteases called calpains aid parasite exit, possibly by acting upon the host cytoskeleton. Together these discoveries reveal important new molecular players involved in the principal steps of egress by apicomplexans.
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Affiliation(s)
- Marijo S Roiko
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, 48109, USA
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200
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Chia J, Yeo KP, Whisstock JC, Dunstone MA, Trapani JA, Voskoboinik I. Temperature sensitivity of human perforin mutants unmasks subtotal loss of cytotoxicity, delayed FHL, and a predisposition to cancer. Proc Natl Acad Sci U S A 2009; 106:9809-14. [PMID: 19487666 PMCID: PMC2701033 DOI: 10.1073/pnas.0903815106] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Indexed: 11/18/2022] Open
Abstract
The pore-forming protein perforin is critical for defense against many human pathogens and for preventing a catastrophic collapse of immune homeostasis, manifested in infancy as Type 2 familial hemophagocytic lymphohistiocytosis (FHL). However, no evidence has yet linked defective perforin cytotoxicity with cancer susceptibility in humans. Here, we examined perforin function in every patient reported in the literature who lived to at least 10 years of age without developing FHL despite inheriting mutations in both of their perforin (PRF1) alleles. Our analysis showed that almost 50% of these patients developed at least 1 hematological malignancy in childhood or adolescence. The broad range of pathologies argued strongly against a common environmental or viral cause for the extraordinary cancer incidence. Functionally, what distinguished these patients was their inheritance of PRF1 alleles encoding temperature-sensitive missense mutations. By contrast, truly null missense mutations with no rescue at the permissive temperature were associated with the more common severe presentation with FHL in early infancy. Our study provides the first mechanistic evidence for a link between defective perforin-mediated cytotoxicity and cancer susceptibility in humans and establishes the paradigm that temperature sensitivity of perforin function is a predictor of FHL severity.
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Affiliation(s)
- Jenny Chia
- Cancer Immunology Program, Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002, Australia
| | - Kim Pin Yeo
- Cancer Immunology Program, Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002, Australia
| | - James C. Whisstock
- Department of Biochemistry and Molecular Biology
- Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, and
| | - Michelle A. Dunstone
- Department of Biochemistry and Molecular Biology
- Department of Microbiology, Monash University, Clayton, Victoria 3800, Australia; and
| | - Joseph A. Trapani
- Cancer Immunology Program, Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002, Australia
- Department of Biochemistry and Molecular Biology
- Department of Microbiology and Immunology and
| | - Ilia Voskoboinik
- Cancer Immunology Program, Peter MacCallum Cancer Centre, St Andrew's Place, East Melbourne, Victoria 3002, Australia
- Department of Genetics, University of Melbourne, Parkville, Victoria 3010, Australia
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