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Gong H, Kobayashi K, Sugi T, Takemae H, Kurokawa H, Horimoto T, Akashi H, Kato K. A novel PAN/apple domain-containing protein from Toxoplasma gondii: characterization and receptor identification. PLoS One 2012; 7:e30169. [PMID: 22276154 PMCID: PMC3261864 DOI: 10.1371/journal.pone.0030169] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 12/14/2011] [Indexed: 12/03/2022] Open
Abstract
Toxoplasma gondii is an intracellular parasite that invades nucleated cells, causing toxoplasmosis in humans and animals worldwide. The extremely wide range of hosts susceptible to T. gondii is thought to be the result of interactions between T. gondii ligands and receptors on its target cells. In this study, a host cell-binding protein from T. gondii was characterized, and one of its receptors was identified. P104 (GenBank Access. No. CAJ20677) is 991 amino acids in length, containing a putative 26 amino acid signal peptide and 10 PAN/apple domains, and shows low homology to other identified PAN/apple domain-containing molecules. A 104-kDa host cell-binding protein was detected in the T. gondii lysate. Immunofluorescence assays detected P104 at the apical end of extracellular T. gondii. An Fc-fusion protein of the P104 N-terminus, which contains two PAN/apple domains, showed strong affinity for the mammalian and insect cells evaluated. This binding was not related to protein-protein or protein-lipid interactions, but to a protein-glycosaminoglycan (GAG) interaction. Chondroitin sulfate (CS), a kind of GAG, was shown to be involved in adhesion of the Fc-P104 N-terminus fusion protein to host cells. These results suggest that P104, expressed at the apical end of the extracellular parasite, may function as a ligand in the attachment of T. gondii to CS or other receptors on the host cell, facilitating invasion by the parasite.
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Affiliation(s)
- Haiyan Gong
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Kyousuke Kobayashi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Tatsuki Sugi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hitoshi Takemae
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hitomi Kurokawa
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Taisuke Horimoto
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Hiroomi Akashi
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Kentaro Kato
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
- * E-mail:
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Farrow RE, Green J, Katsimitsoulia Z, Taylor WR, Holder AA, Molloy JE. The mechanism of erythrocyte invasion by the malarial parasite, Plasmodium falciparum. Semin Cell Dev Biol 2011; 22:953-60. [DOI: 10.1016/j.semcdb.2011.09.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 09/29/2011] [Indexed: 10/24/2022]
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Frénal K, Soldati-Favre D. Role of the parasite and host cytoskeleton in apicomplexa parasitism. Cell Host Microbe 2009; 5:602-11. [PMID: 19527887 DOI: 10.1016/j.chom.2009.05.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 05/22/2009] [Accepted: 05/28/2009] [Indexed: 11/25/2022]
Abstract
The phylum Apicomplexa includes a large and diverse group of obligate intracellular parasites that rely on actomyosin-based motility to migrate, enter host cells, and egress from infected cells. To ensure their intracellular survival and replication, the apicomplexans have evolved sophisticated strategies for subversion of the host cytoskeleton. Given the properties in common between the host and parasite cytoskeleton, dissecting their individual contribution to the establishment of parasitic infection has been challenging. Nevertheless, recent studies have provided new insights into the mechanisms by which parasites subvert the dynamic properties of host actin and tubulin to promote their entry, development, and egress.
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Affiliation(s)
- Karine Frénal
- Department of Microbiology and Molecular Medicine, CMU, University of Geneva, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland.
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Srinivasan S, Baszler T, Vonlaufen N, Leepin A, Sanderson SJ, Wastling JM, Hemphill A. Monoclonal antibody directed against Neospora caninum tachyzoite carbohydrate epitope reacts specifically with apical complex-associated sialylated beta tubulin. J Parasitol 2007; 92:1235-43. [PMID: 17304800 DOI: 10.1645/ge-889r.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Monoclonal antibodies (mabs) were generated against whole sonicated Neospora caninum tachyzoites as immunogen. Initial ELISA screening of the reactivity of hybridoma culture supernatants using the same antigen and antigen treated with sodium periodate prior to antibody binding resulted in the identification of 8 supernatants with reactivity against putative carbohydrate epitopes. Following immunoblotting, mab6D12 (IgG1), binding a 52/48-kDa doublet, and mab6C6 (IgM), binding a 190/180-kDa doublet, were selected for further studies. Immunofluorescence of tachyzoite-infected cultures localized the corresponding epitopes not to the surface, but to interior epitopes at the apical part of N. caninum tachyzoites. During in vitro tachyzoite to bradyzoite stage conversion, mab6C6 labeling translocated toward the cyst periphery, while for mab6D12 no changes in localization were noted. Upon extraction of tachyzoites with the nonionic detergent Triton-X-100, the 52-kDa band recognized by mab6D12 was present exclusively in the insoluble, cytoskeletal fraction of both N. caninum and Toxoplasma gondii tachyzoites. Tandem mass spectrometry analysis identified this protein as N. caninum beta tubulin. The 48-kDa band labeled by mab6D12 was a Vero cell protein contamination. The protein(s) reacting with mab6C6 could not be conclusively identified by mass spectrometry. Immunofluorescence consistently failed to label T. gondii tachyzoites, indicating that beta tubulin in T. gondii and N. caninum could be differentially modified or that the reactive epitope in T. gondii is masked. Immunogold TEM of isolated apical cytoskeletal preparations and dual immunofluorescence with antibody to tubulin confirmed that mab6D12 binds to the anterior part of apical complex-associated microtubules. The sodium periodate sensitivity of the beta tubulin associated epitope was confirmed by immunoblotting and ELISA, and treatment of N. caninum cytoskeletal proteins with sialidase prior to mab6D12 labeling resulted in a profound loss of antibody binding, suggesting that mab6D12 reacts with sialylated beta tubulin.
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Hu K, Johnson J, Florens L, Fraunholz M, Suravajjala S, DiLullo C, Yates J, Roos DS, Murray JM. Cytoskeletal components of an invasion machine--the apical complex of Toxoplasma gondii. PLoS Pathog 2006; 2:e13. [PMID: 16518471 PMCID: PMC1383488 DOI: 10.1371/journal.ppat.0020013] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2005] [Accepted: 01/18/2006] [Indexed: 11/22/2022] Open
Abstract
The apical complex of Toxoplasma gondii is widely believed to serve essential functions in both invasion of its host cells (including human cells), and in replication of the parasite. The understanding of apical complex function, the basis for its novel structure, and the mechanism for its motility are greatly impeded by lack of knowledge of its molecular composition. We have partially purified the conoid/apical complex, identified approximately 200 proteins that represent 70% of its cytoskeletal protein components, characterized seven novel proteins, and determined the sequence of recruitment of five of these proteins into the cytoskeleton during cell division. Our results provide new markers for the different subcompartments within the apical complex, and revealed previously unknown cellular compartments, which facilitate our understanding of how the invasion machinery is built. Surprisingly, the extreme apical and extreme basal structures of this highly polarized cell originate in the same location and at the same time very early during parasite replication.
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Affiliation(s)
- Ke Hu
- Department of Cell Biology, Scripps Research Institute, La Jolla, California, United States of America
| | - Jeff Johnson
- Department of Cell Biology, Scripps Research Institute, La Jolla, California, United States of America
| | - Laurence Florens
- The Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Martin Fraunholz
- Institute of Microbiology, E.-M.-Arndt University, Greifswald, Germany
| | - Sapna Suravajjala
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Camille DiLullo
- Department of Anatomy, Philadelphia College of Osteopathic Medicine, Philadelphia, Pennsylvania, United States of America
| | - John Yates
- Department of Cell Biology, Scripps Research Institute, La Jolla, California, United States of America
| | - David S Roos
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - John M Murray
- Department of Cell & Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Foth BJ, McFadden GI. The apicoplast: a plastid in Plasmodium falciparum and other Apicomplexan parasites. INTERNATIONAL REVIEW OF CYTOLOGY 2003; 224:57-110. [PMID: 12722949 DOI: 10.1016/s0074-7696(05)24003-2] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Apicomplexan parasites cause severe diseases such as malaria, toxoplasmosis, and coccidiosis (caused by Plasmodium spp., Toxoplasma, and Eimeria, respectively). These parasites contain a relict plastid-termed "apicoplast"--that originated from the engulfment of an organism of the red algal lineage. The apicoplast is indispensable but its exact role in parasites is unknown. The apicoplast has its own genome and expresses a small number of genes, but the vast majority of the apicoplast proteome is encoded in the nuclear genome. The products of these nuclear genes are posttranslationally targeted to the organelle via the secretory pathway courtesy of a bipartite N-terminal leader sequence. Apicoplasts are nonphotosynthetic but retain other typical plastid functions such as fatty acid, isoprenoid and heme synthesis, and products of these pathways might be exported from the apicoplast for use by the parasite. Apicoplast pathways are essentially prokaryotic and therefore excellent drug targets. Some antibiotics inhibiting these molecular processes are already in chemotherapeutic use, whereas many new drugs will hopefully spring from our growing understanding of this intriguing organelle.
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Affiliation(s)
- Bernardo J Foth
- Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia
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Abstract
Toxoplasma gondii is an obligatory intracellular parasite, an important human pathogen, and a convenient laboratory model for many other human and veterinary pathogens in the phylum Apicomplexa, such as Plasmodium, Eimeria, and Cryptosporidia. 22 subpellicular microtubules form a scaffold that defines the cell shape of T. gondii. Its cytoskeleton also includes an intricate apical structure consisting of the conoid, two intraconoid microtubules, and two polar rings. The conoid is a 380-nm diameter motile organelle, consisting of fibers wound into a spiral like a compressed spring. FRAP analysis of transgenic T. gondii expressing YFP-alpha-tubulin reveals that the conoid fibers are assembled by rapid incorporation of tubulin subunits during early, but not late, stages of cell division. Electron microscopic analysis shows that in the mature conoid, tubulin is arranged into a novel polymer form that is quite different from typical microtubules.
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Affiliation(s)
- Ke Hu
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Morrissette NS, Sibley LD. Disruption of microtubules uncouples budding and nuclear division inToxoplasma gondii. J Cell Sci 2002; 115:1017-25. [PMID: 11870220 DOI: 10.1242/jcs.115.5.1017] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tachyzoite stage of the protozoan parasite Toxoplasma gondiihas two populations of microtubules: spindle microtubules and subpellicular microtubules. To determine how these two microtubule populations are regulated, we investigated microtubule behavior during the cell cycle following treatment with microtubule-disrupting drugs. Previous work had established that the microtubule populations are individually nucleated by two distinct microtubule-organizing centers (MTOCs): the apical polar ring for the subpellicular microtubules and spindle pole plaques/centrioles for the spindle microtubules. When replicating tachyzoites were treated with 0.5 μM oryzalin or 1.0 mM colchicine they retained the capacity to form a spindle and undergo nuclear division. Although these parasites could complete budding,they lost the bulk of their subpellicular microtubules and the ability to reinvade host cells. Both nascent spindle and subpellicular microtubules were disrupted in 2.5 μM oryzalin or 5.0 mM colchicine. Under these conditions,parasites grew in size and replicated their genome but were incapable of nuclear division. After removal from 0.5 μM oryzalin, Toxoplasmatachyzoites were able to restore normal subpellicular microtubules and a fully invasive phenotype. When oryzalin was removed from Toxoplasmatachyzoites treated with 2.5 μM drug, the parasites attempted to bud as crescent-shaped tachyzoites. Because the polyploid nuclear mass could not be correctly segregated, many daughter parasites lacked nuclei altogether although budding and scission from the maternal mass was able to be completed. Multiple MTOCs permit Toxoplasma tachyzoites to control nuclear division independently from cell polarity and cytokinesis. This unusual situation grants greater cell cycle flexibility to these parasites but abolishes the checks for coregulation of nuclear division and cytokinesis found in other eukaryotes.
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Affiliation(s)
- Naomi S Morrissette
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis MO 63110, USA.
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Abstract
The Apicomplexa are a phylum of diverse obligate intracellular parasites including Plasmodium spp., the cause of malaria; Toxoplasma gondii and Cryptosporidium parvum, opportunistic pathogens of immunocompromised individuals; and Eimeria spp. and Theileria spp., parasites of considerable agricultural importance. These protozoan parasites share distinctive morphological features, cytoskeletal organization, and modes of replication, motility, and invasion. This review summarizes our current understanding of the cytoskeletal elements, the properties of cytoskeletal proteins, and the role of the cytoskeleton in polarity, motility, invasion, and replication. We discuss the unusual properties of actin and myosin in the Apicomplexa, the highly stereotyped microtubule populations in apicomplexans, and a network of recently discovered novel intermediate filament-like elements in these parasites.
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Affiliation(s)
- Naomi S Morrissette
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Fowler RE, Smith AM, Whitehorn J, Williams IT, Bannister LH, Mitchell GH. Microtubule associated motor proteins of Plasmodium falciparum merozoites. Mol Biochem Parasitol 2001; 117:187-200. [PMID: 11606229 DOI: 10.1016/s0166-6851(01)00351-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have studied the occurrence, stage specificity and cellular location of key molecules associated with microtubules in Plasmodium falciparum merozoites. Antibodies to gamma tubulin, conventional kinesin and cytoplasmic dynein were used to determine the polarity of merozoite microtubules (mt), the stage specificity of the motor proteins and their location during merozoite development. We conclude that the minus ends of the mts are located at their apical pole. Kinesin was present throughout the lifecycle, appearing as a distinct crescent at the apex of developing merozoites. The vast majority of cytoplasmic dynein reactivity occurred in late merogony, also appearing at the merozoite apex. Destruction of mt with dinitroanilines did not affect the cellular location of kinesin or dynein. In invasion assays, dynein inhibitors reduced the number of ring stage parasites. Our results show that both conventional kinesin and cytoplasmic dynein are abundant, located at the negative pole of the merozoite mt and, intriguingly, appear there only in very late merogony, prior to merozoite release and invasion.
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Affiliation(s)
- R E Fowler
- Malaria Laboratory, Department of Immunobiology, Guy's, King's and St Thomas' School of Medicine, KCL, Guy's Hospital, London Bridge, London, SE1 9RT, UK.
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11
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Reiss M, Viebig N, Brecht S, Fourmaux MN, Soete M, Di Cristina M, Dubremetz JF, Soldati D. Identification and characterization of an escorter for two secretory adhesins in Toxoplasma gondii. J Cell Biol 2001; 152:563-78. [PMID: 11157983 PMCID: PMC2196004 DOI: 10.1083/jcb.152.3.563] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The intracellular protozoan parasite Toxoplasma gondii shares with other members of the Apicomplexa a common set of apical structures involved in host cell invasion. Micronemes are apical secretory organelles releasing their contents upon contact with host cells. We have identified a transmembrane micronemal protein MIC6, which functions as an escorter for the accurate targeting of two soluble proteins MIC1 and MIC4 to the micronemes. Disruption of MIC1, MIC4, and MIC6 genes allowed us to precisely dissect their contribution in sorting processes. We have mapped domains on these proteins that determine complex formation and targeting to the organelle. MIC6 carries a sorting signal(s) in its cytoplasmic tail whereas its association with MIC1 involves a lumenal EGF-like domain. MIC4 binds directly to MIC1 and behaves as a passive cargo molecule. In contrast, MIC1 is linked to a quality control system and is absolutely required for the complex to leave the early compartments of the secretory pathway. MIC1 and MIC4 bind to host cells, and the existence of such a complex provides a plausible mechanism explaining how soluble adhesins act. We hypothesize that during invasion, MIC6 along with adhesins establishes a bridge between the host cell and the parasite.
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Affiliation(s)
- Matthias Reiss
- Center for Molecular Biology, University of Heidelberg, Heidelberg D-63120, Germany
| | - Nicola Viebig
- Center for Molecular Biology, University of Heidelberg, Heidelberg D-63120, Germany
| | - Susan Brecht
- Center for Molecular Biology, University of Heidelberg, Heidelberg D-63120, Germany
| | | | - Martine Soete
- Institute of Biology CNRS, Institut Pasteur de Lille, Lille, 59019 France
| | - Manlio Di Cristina
- Department of Cell Biology, Imperial College of Science, Technology, and Medicine, London, SW7 2AZ United Kingdom
| | | | - Dominique Soldati
- Center for Molecular Biology, University of Heidelberg, Heidelberg D-63120, Germany
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Striepen B, Crawford MJ, Shaw MK, Tilney LG, Seeber F, Roos DS. The plastid of Toxoplasma gondii is divided by association with the centrosomes. J Cell Biol 2000; 151:1423-34. [PMID: 11134072 PMCID: PMC2150670 DOI: 10.1083/jcb.151.7.1423] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Apicomplexan parasites harbor a single nonphotosynthetic plastid, the apicoplast, which is essential for parasite survival. Exploiting Toxoplasma gondii as an accessible system for cell biological analysis and molecular genetic manipulation, we have studied how these parasites ensure that the plastid and its 35-kb circular genome are faithfully segregated during cell division. Parasite organelles were labeled by recombinant expression of fluorescent proteins targeted to the plastid and the nucleus, and time-lapse video microscopy was used to image labeled organelles throughout the cell cycle. Apicoplast division is tightly associated with nuclear and cell division and is characterized by an elongated, dumbbell-shaped intermediate. The plastid genome is divided early in this process, associating with the ends of the elongated organelle. A centrin-specific antibody demonstrates that the ends of dividing apicoplast are closely linked to the centrosomes. Treatment with dinitroaniline herbicides (which disrupt microtubule organization) leads to the formation of multiple spindles and large reticulate plastids studded with centrosomes. The mitotic spindle and the pellicle of the forming daughter cells appear to generate the force required for apicoplast division in Toxoplasma gondii. These observations are discussed in the context of autonomous and FtsZ-dependent division of plastids in plants and algae.
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Affiliation(s)
- B Striepen
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia 30602, USA.
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