1
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Halliday C, de Liz LV, Vaughan S, Sunter JD. Disruption of Leishmania flagellum attachment zone architecture causes flagellum loss. Mol Microbiol 2024; 121:53-68. [PMID: 38010644 PMCID: PMC10953051 DOI: 10.1111/mmi.15199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/10/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023]
Abstract
Leishmania are flagellated eukaryotic parasites that cause leishmaniasis and are closely related to the other kinetoplastid parasites such as Trypanosoma brucei. In all these parasites there is a cell membrane invagination at the base of the flagellum called the flagellar pocket, which is tightly associated with and sculpted by cytoskeletal structures including the flagellum attachment zone (FAZ). The FAZ is a complex interconnected structure linking the flagellum to the cell body and has critical roles in cell morphogenesis, function and pathogenicity. However, this structure varies dramatically in size and organisation between these different parasites, suggesting changes in protein localisation and function. Here, we screened the localisation and function of the Leishmania orthologues of T. brucei FAZ proteins identified in the genome-wide protein tagging project TrypTag. We identified 27 FAZ proteins and our deletion analysis showed that deletion of two FAZ proteins in the flagellum, FAZ27 and FAZ34 resulted in a reduction in cell body size, and flagellum loss in some cells. Furthermore, after null mutant generation, we observed distinct and reproducible changes to cell shape, demonstrating the ability of the parasite to adapt to morphological perturbations resulting from gene deletion. This process of adaptation has important implications for the study of Leishmania mutants.
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Affiliation(s)
- Clare Halliday
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
| | - Laryssa Vanessa de Liz
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
- Departamento de Microbiologia, Imunologia e ParasitologiaUniversidade Federal de Santa CatarinaFlorianópolisSCBrazil
| | - Sue Vaughan
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
| | - Jack D. Sunter
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
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2
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Aeschlimann S, Stettler P, Schneider A. DNA segregation in mitochondria and beyond: insights from the trypanosomal tripartite attachment complex. Trends Biochem Sci 2023; 48:1058-1070. [PMID: 37775421 DOI: 10.1016/j.tibs.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/13/2023] [Accepted: 08/28/2023] [Indexed: 10/01/2023]
Abstract
The tripartite attachment complex (TAC) of the single mitochondrion of trypanosomes allows precise segregation of its single nucleoid mitochondrial genome during cytokinesis. It couples the segregation of the duplicated mitochondrial genome to the segregation of the basal bodies of the flagella. Here, we provide a model of the molecular architecture of the TAC that explains how its eight essential subunits connect the basal body, across the mitochondrial membranes, with the mitochondrial genome. We also discuss how the TAC subunits are imported into the mitochondrion and how they assemble to form a new TAC. Finally, we present a comparative analysis of the trypanosomal TAC with open and closed mitotic spindles, which reveals conserved concepts between these diverse DNA segregation systems.
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Affiliation(s)
- Salome Aeschlimann
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - Philip Stettler
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern CH-3012, Switzerland
| | - André Schneider
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Institute for Advanced Study (Wissenschaftskolleg) Berlin, D-14193 Berlin, Germany.
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3
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Campbell PC, de Graffenried CL. Morphogenesis in Trypanosoma cruzi epimastigotes proceeds via a highly asymmetric cell division. PLoS Negl Trop Dis 2023; 17:e0011731. [PMID: 37917723 PMCID: PMC10656021 DOI: 10.1371/journal.pntd.0011731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 11/17/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023] Open
Abstract
Trypanosoma cruzi is a protist parasite that is the causative agent of Chagas disease, a neglected tropical disease endemic to the Americas. T. cruzi cells are highly polarized and undergo morphological changes as they cycle within their insect and mammalian hosts. Work on related trypanosomatids has described cell division mechanisms in several life-cycle stages and identified a set of essential morphogenic proteins that serve as markers for key events during trypanosomatid division. Here, we use Cas9-based tagging of morphogenic genes, live-cell imaging, and expansion microscopy to study the cell division mechanism of the insect-resident epimastigote form of T. cruzi, which represents an understudied trypanosomatid morphotype. We find that T. cruzi epimastigote cell division is highly asymmetric, producing one daughter cell that is significantly smaller than the other. Daughter cell division rates differ by 4.9 h, which may be a consequence of this size disparity. Many of the morphogenic proteins identified in T. brucei have altered localization patterns in T. cruzi epimastigotes, which may reflect fundamental differences in the cell division mechanism of this life cycle stage, which widens and shortens the cell body to accommodate the duplicated organelles and cleavage furrow rather than elongating the cell body along the long axis of the cell, as is the case in life-cycle stages that have been studied in T. brucei. This work provides a foundation for further investigations of T. cruzi cell division and shows that subtle differences in trypanosomatid cell morphology can alter how these parasites divide.
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Affiliation(s)
- Paul C. Campbell
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
| | - Christopher L. de Graffenried
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, United States of America
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4
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Souza Onofre T, Pham KTM, Zhou Q, Li Z. The microtubule quartet protein SNAP1 in Trypanosoma brucei facilitates flagellum and cell division plane positioning by promoting basal body segregation. J Biol Chem 2023; 299:105340. [PMID: 37838178 PMCID: PMC10656233 DOI: 10.1016/j.jbc.2023.105340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/21/2023] [Accepted: 10/07/2023] [Indexed: 10/16/2023] Open
Abstract
The unicellular protozoan Trypanosoma brucei has a single flagellum that is involved in cell motility, cell morphogenesis, and cell division. Inheritance of the newly assembled flagellum during the cell cycle requires its correct positioning, which depends on the faithful duplication or segregation of multiple flagellum-associated cytoskeletal structures, including the basal body, the flagellum attachment zone, and the hook complex. Along the flagellum attachment zone sites a set of four microtubules termed the microtubule quartet (MtQ), whose molecular function remains enigmatic. We recently reported that the MtQ-localized protein NHL1 interacts with the microtubule-binding protein TbSpef1 and regulates flagellum inheritance by promoting basal body rotation and segregation. Here, we identified a TbSpef1- and NHL1-associated protein named SNAP1, which co-localizes with NHL1 and TbSpef1 at the proximal portion of the MtQ, depends on TbSpef1 for localization and is required for NHL1 localization to the MtQ. Knockdown of SNAP1 impairs the rotation and segregation of the basal body, the elongation of the flagellum attachment zone filament, and the positioning of the newly assembled flagellum, thereby causing mis-placement of the cell division plane, a halt in cleavage furrow ingression, and an inhibition of cytokinesis completion. Together, these findings uncover a coordinating role of SNAP1 with TbSpef1 and NHL1 in facilitating flagellum positioning and cell division plane placement for the completion of cytokinesis.
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Affiliation(s)
- Thiago Souza Onofre
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Kieu T M Pham
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Qing Zhou
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA.
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5
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Schichler D, Konle A, Spath EM, Riegler S, Klein A, Seleznev A, Jung S, Wuppermann T, Wetterich N, Borges A, Meyer-Natus E, Havlicek K, Pérez Cabrera S, Niedermüller K, Sajko S, Dohn M, Malzer X, Riemer E, Tumurbaatar T, Djinovic-Carugo K, Dong G, Janzen CJ, Morriswood B. Characterisation of TbSmee1 suggests endocytosis allows surface-bound cargo to enter the trypanosome flagellar pocket. J Cell Sci 2023; 136:jcs261548. [PMID: 37737012 PMCID: PMC10652038 DOI: 10.1242/jcs.261548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/23/2023] Open
Abstract
All endocytosis and exocytosis in the African trypanosome Trypanosoma brucei occurs at a single subdomain of the plasma membrane. This subdomain, the flagellar pocket, is a small vase-shaped invagination containing the root of the single flagellum of the cell. Several cytoskeleton-associated multiprotein complexes are coiled around the neck of the flagellar pocket on its cytoplasmic face. One of these, the hook complex, was proposed to affect macromolecule entry into the flagellar pocket lumen. In previous work, knockdown of T. brucei (Tb)MORN1, a hook complex component, resulted in larger cargo being unable to enter the flagellar pocket. In this study, the hook complex component TbSmee1 was characterised in bloodstream form T. brucei and found to be essential for cell viability. TbSmee1 knockdown resulted in flagellar pocket enlargement and impaired access to the flagellar pocket membrane by surface-bound cargo, similar to depletion of TbMORN1. Unexpectedly, inhibition of endocytosis by knockdown of clathrin phenocopied TbSmee1 knockdown, suggesting that endocytic activity itself is a prerequisite for the entry of surface-bound cargo into the flagellar pocket.
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Affiliation(s)
- Daja Schichler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Antonia Konle
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Eva-Maria Spath
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sina Riegler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Alexandra Klein
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Anna Seleznev
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sisco Jung
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Timothy Wuppermann
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Noah Wetterich
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Alyssa Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Elisabeth Meyer-Natus
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Katharina Havlicek
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | | | - Korbinian Niedermüller
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Maximilian Dohn
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Xenia Malzer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Emily Riemer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Tuguldur Tumurbaatar
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana, Slovenia
- European Molecular Biology Laboratory (EMBL) Grenoble, 38000 Grenoble, France
| | - Gang Dong
- Center for Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria
| | - Christian J. Janzen
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
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6
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Campbell PC, de Graffenried CL. Morphogenesis in Trypanosoma cruzi epimastigotes proceeds via a highly asymmetric cell division. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.24.542100. [PMID: 37293088 PMCID: PMC10245916 DOI: 10.1101/2023.05.24.542100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Trypanosoma cruzi is a protist parasite that is the causative agent of Chagas' disease, a neglected tropical disease endemic to the Americas. T. cruzi cells are highly polarized and undergo morphological changes as they cycle within their insect and mammalian hosts. Work on related trypanosomatids has described cell division mechanisms in several life-cycle stages and identified a set of essential morphogenic proteins that serve as markers for key events during trypanosomatid division. Here, we use Cas9-based tagging of morphogenic genes, live-cell imaging, and expansion microscopy to study the cell division mechanism of the insect-resident epimastigote form of T. cruzi, which represents an understudied trypanosomatid morphotype. We find that T. cruzi epimastigote cell division is highly asymmetric, producing one daughter cell that is significantly smaller than the other. Daughter cell division rates differ by 4.9 h, which may be a consequence of this size disparity. Many of the morphogenic proteins identified in T. brucei have altered localization patterns in T. cruzi epimastigoes, which may reflect fundamental differences in the cell division mechanism of this life cycle stage, which widens and shortens the cell body to accommodate the duplicated organelles and cleavage furrow rather than elongating the cell body along the long axis of the cell, as is the case in life-cycle stages that have been studied in T. brucei. This work provides a foundation for further investigations of T. cruzi cell division and shows that subtle differences in trypansomatid cell morphology can alter how these parasites divide.
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Affiliation(s)
- Paul C. Campbell
- Department of Molecular Microbiology and Immunology, Brown University, Providence, Rhode Island, USA
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7
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Genome-wide subcellular protein map for the flagellate parasite Trypanosoma brucei. Nat Microbiol 2023; 8:533-547. [PMID: 36804636 PMCID: PMC9981465 DOI: 10.1038/s41564-022-01295-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/21/2022] [Indexed: 02/22/2023]
Abstract
Trypanosoma brucei is a model trypanosomatid, an important group of human, animal and plant unicellular parasites. Understanding their complex cell architecture and life cycle is challenging because, as with most eukaryotic microbes, ~50% of genome-encoded proteins have completely unknown functions. Here, using fluorescence microscopy and cell lines expressing endogenously tagged proteins, we mapped the subcellular localization of 89% of the T. brucei proteome, a resource we call TrypTag. We provide clues to function and define lineage-specific organelle adaptations for parasitism, mapping the ultraconserved cellular architecture of eukaryotes, including the first comprehensive 'cartographic' analysis of the eukaryotic flagellum, which is vital for morphogenesis and pathology. To demonstrate the power of this resource, we identify novel organelle subdomains and changes in molecular composition through the cell cycle. TrypTag is a transformative resource, important for hypothesis generation for both eukaryotic evolutionary molecular cell biology and fundamental parasite cell biology.
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8
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Benz C, Müller N, Kaltenbrunner S, Váchová H, Vancová M, Lukeš J, Varga V, Hashimi H. Kinetoplastid-specific X2-family kinesins interact with a kinesin-like pleckstrin homology domain protein that localizes to the trypanosomal microtubule quartet. Mol Microbiol 2022; 118:155-174. [PMID: 35766104 DOI: 10.1111/mmi.14958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 11/28/2022]
Abstract
Kinesins are motor proteins found in all eukaryotic lineages that move along microtubules to mediate cellular processes such as mitosis and intracellular transport. In trypanosomatids, the kinesin superfamily has undergone a prominent expansion, resulting in one of the most diverse kinesin repertoires that includes the two kinetoplastid-restricted families X1 and X2. Here, we characterize in Trypanosoma brucei TbKifX2A, an orphaned X2 kinesin. TbKifX2A tightly interacts with TbPH1, a kinesin-like protein with a likely inactive motor domain, a rarely reported occurrence. Both TbKifX2A and TbPH1 localize to the microtubule quartet (MtQ), a characteristic but poorly understood cytoskeletal structure that wraps around the flagellar pocket as it extends to the cell body anterior. The proximal proteome of TbPH1 revealed two other interacting proteins, the flagellar pocket protein FP45 and intriguingly another X2 kinesin, TbKifX2C. Simultaneous ablation of TbKifX2A/TbPH1 results in the depletion of FP45 and TbKifX2C and also an expansion of the flagellar pocket, among other morphological defects. TbKifX2A is the first motor protein to be localized to the MtQ. The observation that TbKifX2C also associates with the MtQ suggests that the X2 kinesin family may have co-evolved with the MtQ, both kinetoplastid-specific traits.
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Affiliation(s)
- Corinna Benz
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia
| | - Nora Müller
- Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Sabine Kaltenbrunner
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia.,Johannes Kepler University, Medical Faculty, Linz, Austria
| | - Hana Váchová
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Marie Vancová
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Julius Lukeš
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Vladimír Varga
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Hassan Hashimi
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
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9
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A Spef1-interacting microtubule quartet protein in Trypanosoma brucei promotes flagellar inheritance by regulating basal body segregation. J Biol Chem 2022; 298:102125. [PMID: 35697071 PMCID: PMC9257412 DOI: 10.1016/j.jbc.2022.102125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 11/24/2022] Open
Abstract
The human parasite Trypanosoma brucei contains a motile flagellum that determines the plane of cell division, controls cell morphology, and mediates cell-cell communication. During the cell cycle, inheritance of the newly formed flagellum requires its correct positioning toward the posterior of the cell, which depends on the faithful segregation of multiple flagellum-associated cytoskeletal structures including the basal body, the flagellar pocket collar, the flagellum attachment zone, and the hook complex. A specialized group of four microtubules termed the microtubule quartet (MtQ) originates from the basal body and runs through the flagellar pocket collar and the hook complex to extend, along the flagellum attachment zone, toward the anterior of the cell. However, the physiological function of the MtQ is poorly understood, and few MtQ-associated proteins have been identified and functionally characterized. We report here that an MtQ-localized protein named NHL1 interacts with the microtubule-binding protein TbSpef1 and depends on TbSpef1 for its localization to the MtQ. We show that RNAi-mediated knockdown of NHL1 impairs the segregation of flagellum-associated cytoskeletal structures, resulting in mispositioning of the new flagellum. Furthermore, knockdown of NHL1 also causes misplacement of the cell division plane in dividing trypanosome cells, halts cleavage furrow ingression, and inhibits completion of cytokinesis. These findings uncover a crucial role for the MtQ-associated protein NHL1 in regulating basal body segregation to promote flagellar inheritance in T. brucei.
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10
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Sáez Conde J, Dean S. Structure, function and druggability of the African trypanosome flagellum. J Cell Physiol 2022; 237:2654-2667. [PMID: 35616248 PMCID: PMC9323424 DOI: 10.1002/jcp.30778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
African trypanosomes are early branching protists that cause human and animal diseases, termed trypanosomiases. They have been under intensive study for more than 100 years and have contributed significantly to our understanding of eukaryotic biology. The combination of conserved and parasite‐specific features mean that their flagellum has gained particular attention. Here, we discuss the different structural features of the flagellum and their role in transmission and virulence. We highlight the possibilities of targeting flagellar function to cure trypanosome infections and help in the fight to eliminate trypanosomiases.
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Affiliation(s)
- Julia Sáez Conde
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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11
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Ramanantsalama MR, Landrein N, Casas E, Salin B, Blancard C, Bonhivers M, Robinson DR, Dacheux D. TFK1, a basal body transition fibre protein that is essential for cytokinesis in Trypanosoma brucei. J Cell Sci 2022; 135:275643. [PMID: 35588197 DOI: 10.1242/jcs.259893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
In Trypanosoma brucei, transition fibres (TF) form a nine-bladed pattern-like structure connecting the base of the flagellum to the flagellar pocket membrane. Despite the characterization of two TF proteins, CEP164C and TbRP2, little is known about the organization of these fibres. Here, we report the identification and characterization of the first kinetoplastid-specific TF protein named TFK1 (Tb927.6.1180). Bioinformatics and functional domain analysis identified three TFK1 distinct domains: an N-terminal domain of an unpredicted function, a coiled-coil domain involved in TFK1-TFK1 interaction and a C-terminal intrinsically disordered region potentially involved in protein interaction. Cellular immuno-localization showed that TFK1 is a newly identified basal body maturation marker. Further, using ultrastructure expansion and immuno-electron microscopies we localized CEP164C and TbRP2 at the TF and TFK1 on the distal appendage matrix of the TF. Importantly, RNAi knockdown of TFK1 in bloodstream form cells induced misplacement of basal bodies, a defect in the furrow or fold generation and eventually cell death. We hypothesize that TFK1 is a basal body positioning specific actor and a key regulator of cytokinesis in the bloodstream form Trypanosoma brucei.
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Affiliation(s)
| | - Nicolas Landrein
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Elina Casas
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Bénédicte Salin
- University of Bordeaux, CNRS, Microscopy Department IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Corinne Blancard
- University of Bordeaux, CNRS, Microscopy Department IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Mélanie Bonhivers
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Derrick R Robinson
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Denis Dacheux
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.,Bordeaux INP, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
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12
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Cavalier-Smith T. Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi. PROTOPLASMA 2022; 259:487-593. [PMID: 34940909 PMCID: PMC9010356 DOI: 10.1007/s00709-021-01665-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/03/2021] [Indexed: 05/19/2023]
Abstract
I thoroughly discuss ciliary transition zone (TZ) evolution, highlighting many overlooked evolutionarily significant ultrastructural details. I establish fundamental principles of TZ ultrastructure and evolution throughout eukaryotes, inferring unrecognised ancestral TZ patterns for Fungi, opisthokonts, and Corticata (i.e., kingdoms Plantae and Chromista). Typical TZs have a dense transitional plate (TP), with a previously overlooked complex lattice as skeleton. I show most eukaryotes have centriole/TZ junction acorn-V filaments (whose ancestral function was arguably supporting central pair microtubule-nucleating sites; I discuss their role in centriole growth). Uniquely simple malawimonad TZs (without TP, simpler acorn) pinpoint the eukaryote tree's root between them and TP-bearers, highlighting novel superclades. I integrate TZ/ciliary evolution with the best multiprotein trees, naming newly recognised major eukaryote clades and revise megaclassification of basal kingdom Protozoa. Recent discovery of non-photosynthetic phagotrophic flagellates with genome-free plastids (Rhodelphis), the sister group to phylum Rhodophyta (red algae), illuminates plant and chromist early evolution. I show previously overlooked marked similarities in cell ultrastructure between Rhodelphis and Picomonas, formerly considered an early diverging chromist. In both a nonagonal tube lies between their TP and an annular septum surrounding their 9+2 ciliary axoneme. Mitochondrial dense condensations and mitochondrion-linked smooth endomembrane cytoplasmic partitioning cisternae further support grouping Picomonadea and Rhodelphea as new plant phylum Pararhoda. As Pararhoda/Rhodophyta form a robust clade on site-heterogeneous multiprotein trees, I group Pararhoda and Rhodophyta as new infrakingdom Rhodaria of Plantae within subkingdom Biliphyta, which also includes Glaucophyta with fundamentally similar TZ, uniquely in eukaryotes. I explain how biliphyte TZs generated viridiplant stellate-structures.
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Vidal JC, De Souza W. 3D FIB-SEM structural insights into the architecture of sub-pellicular microtubules of Trypanosoma cruzi epimastigotes. Biol Cell 2022; 114:203-210. [PMID: 35475518 DOI: 10.1111/boc.202100038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 03/05/2022] [Accepted: 03/07/2022] [Indexed: 11/26/2022]
Abstract
BACKGROUND INFORMATION Trypanosomatidae, which includes eukaryotic species agents of diseases like leishmaniasis, sleeping sickness, and Chagas disease, have special structures and organelles not found in mammalian cells. They present a layer of microtubules, known as subpellicular microtubules (SPMT), located underneath the plasma membrane and responsible for preserving cell morphology, cell polarity, the position of single copy organelles, and morphological changes that occur throughout the protozoan life cycle. Even though a lot of knowledge about the SPMT is available, we still do not know exactly how each microtubule in the system is organized in three dimensions. Here, we use focused ion beam scanning electron microscopy (FIB-SEM) to analyze the tridimensional organization of epimastigotes SPMT. RESULTS The high-resolution 3D analyses revealed that certain microtubules of the SPMT end more prematurely than the neighboring ones. CONCLUSIONS These microtubules could (1) be shorter or (2) have the same length as the neighboring ones, assuming that those end up earlier at their other end, might be treadmilling/catastrophe events that have not yet been described in trypanosomatids.
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Affiliation(s)
- Juliana C Vidal
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Wanderley De Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Broster Reix CE, Florimond C, Cayrel A, Mailhé A, Agnero-Rigot C, Landrein N, Dacheux D, Havlicek K, Bonhivers M, Morriswood B, Robinson DR. Bhalin, an Essential Cytoskeleton-Associated Protein of Trypanosoma brucei Linking TbBILBO1 of the Flagellar Pocket Collar with the Hook Complex. Microorganisms 2021; 9:microorganisms9112334. [PMID: 34835460 PMCID: PMC8623173 DOI: 10.3390/microorganisms9112334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/26/2021] [Accepted: 11/04/2021] [Indexed: 12/31/2022] Open
Abstract
Background: In most trypanosomes, endo and exocytosis only occur at a unique organelle called the flagellar pocket (FP) and the flagellum exits the cell via the FP. Investigations of essential cytoskeleton-associated structures located at this site have revealed a number of essential proteins. The protein TbBILBO1 is located at the neck of the FP in a structure called the flagellar pocket collar (FPC) and is essential for biogenesis of the FPC and parasite survival. TbMORN1 is a protein that is present on a closely linked structure called the hook complex (HC) and is located anterior to and overlapping the collar. TbMORN1 is essential in the bloodstream form of T. brucei. We now describe the location and function of BHALIN, an essential, new FPC-HC protein. Methodology/Principal Findings: Here, we show that a newly characterised protein, BHALIN (BILBO1 Hook Associated LINker protein), is localised to both the FPC and HC and has a TbBILBO1 binding domain, which was confirmed in vitro. Knockdown of BHALIN by RNAi in the bloodstream form parasites led to cell death, indicating an essential role in cell viability. Conclusions/Significance: Our results demonstrate the essential role of a newly characterised hook complex protein, BHALIN, that influences flagellar pocket organisation and function in bloodstream form T. brucei parasites.
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Affiliation(s)
- Christine E. Broster Reix
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
| | - Célia Florimond
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
- Laboratory of Parasitology, National Reference Center for Malaria, WHO Collaborative Center for Surveillance of Antimalarial Drug Resistance, Pasteur Institute of French Guiana, 97306 Cayenne, French Guiana
| | - Anne Cayrel
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
| | - Amélie Mailhé
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
- Société Fromagère de Saint Affrique, Camaras, 12400 Saint-Affrique, France
| | - Corentin Agnero-Rigot
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
| | - Nicolas Landrein
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
| | - Denis Dacheux
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
- Enstbb, École Nationale Supérieure de Technologie des Biomolécules de Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France
| | - Katharina Havlicek
- Max Perutz Labs, Vienna BioCenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria;
| | - Mélanie Bonhivers
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
| | - Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany;
| | - Derrick R. Robinson
- Protist Parasite Cytoskeleton (ProParaCyto) Group, CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, University of Bordeaux, 146 Rue Léo Saignat, 33076 Bordeaux, France; (C.E.B.R.); (C.F.); (A.C.); (A.M.); (C.A.-R.); (N.L.); (D.D.); (M.B.)
- Correspondence:
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Abstract
Trypanosoma brucei belongs to a genus of protists that cause life-threatening and economically important diseases of human and animal populations in Sub-Saharan Africa. T. brucei cells are covered in surface glycoproteins, some of which are used to escape the host immune system. Exo-/endocytotic trafficking of these and other molecules occurs via a single copy organelle called the flagellar pocket (FP). The FP is maintained and enclosed around the flagellum by the flagellar pocket collar (FPC). To date, the most important cytoskeletal component of the FPC is an essential calcium-binding, polymer-forming protein called TbBILBO1. In searching for novel tools to study this protein, we raised nanobodies (Nb) against purified, full-length TbBILBO1. Nanobodies were selected according to their binding properties to TbBILBO1, tested as immunofluorescence tools, and expressed as intrabodies (INb). One of them, Nb48, proved to be the most robust nanobody and intrabody. We further demonstrate that inducible, cytoplasmic expression of INb48 was lethal to these parasites, producing abnormal phenotypes resembling those of TbBILBO1 RNA interference (RNAi) knockdown. Our results validate the feasibility of generating functional single-domain antibody-derived intrabodies to target trypanosome cytoskeleton proteins. IMPORTANCETrypanosoma brucei belongs to a group of important zoonotic parasites. We investigated how these organisms develop their cytoskeleton (the internal skeleton that controls cell shape) and focused on an essential protein (BILBO1) first described in T. brucei. To develop our analysis, we used purified BILBO1 protein to immunize an alpaca to make nanobodies (Nb). Nanobodies are derived from the antigen-binding portion of a novel antibody type found only in the camel and shark families of animals. Anti-BILBO1 nanobodies were obtained, and their encoding genes were inducibly expressed within the cytoplasm of T. brucei as intrabodies (INb). Importantly, INb48 expression rapidly killed parasites producing phenotypes normally observed after RNA knockdown, providing clear proof of principle. The importance of this study is derived from this novel approach, which can be used to study neglected and emerging pathogens as well as new model organisms, especially those that do not have the RNAi system.
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Novel Cytoskeleton-Associated Proteins in Trypanosoma brucei Are Essential for Cell Morphogenesis and Cytokinesis. Microorganisms 2021; 9:microorganisms9112234. [PMID: 34835360 PMCID: PMC8625193 DOI: 10.3390/microorganisms9112234] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 11/24/2022] Open
Abstract
Trypanosome brucei, the causative agent of African sleeping sickness, harbours a highly ordered, subpellicular microtubule cytoskeleton that defines many aspects of morphology, motility and virulence. This array of microtubules is associated with a large number of proteins involved in its regulation. Employing proximity-dependent biotinylation assay (BioID) using the well characterised cytoskeleton-associated protein CAP5.5 as a probe, we identified CAP50 (Tb927.11.2610). This protein colocalises with the subpellicular cytoskeleton microtubules but not with the flagellum. Depletion by RNAi results in defects in cytokinesis, morphology and partial disorganisation of microtubule arrays. Published proteomics data indicate a possible association of CAP50 with two other, yet uncharacterised, cytoskeletal proteins, CAP52 (Tb927.6.5070) and CAP42 (Tb927.4.1300), which were therefore included in our analysis. We show that their depletion causes phenotypes similar to those described for CAP50 and that they are essential for cellular integrity.
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Abstract
The recently developed ultrastructure expansion microscopy (U-ExM) technique allows us to increase the spatial resolution within a cell or tissue for microscopic imaging through the physical expansion of the sample. In this study, we validate the use of U-ExM in Trypanosoma brucei measuring the expansion factors of several different compartments/organelles and thus verify the isotropic expansion of the cell. We furthermore demonstrate the use of this sample preparation protocol for future studies by visualizing the nucleus and kDNA, as well as proteins of the cytoskeleton, the basal body, the mitochondrion and the endoplasmic reticulum. Lastly, we discuss the challenges and opportunities of U-ExM.
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Affiliation(s)
- Ana Kalichava
- Institute of Cell Biology, University of Bern, Switzerland,Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland
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Comparison of Ciliary Targeting of Two Rhodopsin-Like GPCRs: Role of C-Terminal Localization Sequences in Relation to Cilium Type. J Neurosci 2021; 41:7514-7531. [PMID: 34301828 PMCID: PMC8425976 DOI: 10.1523/jneurosci.0357-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/20/2021] [Accepted: 06/16/2021] [Indexed: 11/21/2022] Open
Abstract
Primary cilia exhibit a distinct complement of proteins, including G-protein-coupled receptors (GPCRs) that mediate sensory and developmental signals. The localization of GPCRs to the ciliary membrane involves ciliary localization sequences (CLSs), but it is not known how CLSs might relate to cilium type. Here, we studied the localization of two rhodopsin (RHO)-like GPCRs, somatostatin receptor (SSTR3) and RHO, in three types of cilia, from inner medullary collecting duct (IMCD3) cells, hTERT-RPE1 cells (possessing pocket cilia), and rod photoreceptors (whose cilia grow into elaborate phototransductive outer segments). SSTR3 was localized specifically to all three types of cilia, whereas RHO showed more selectivity for the photoreceptor cilium. Focusing on C-terminal CLSs, we characterized a novel CLS in the SSTR3 C terminus, which was required for the robust ciliary localization of SSTR3. Replacing the C terminus of RHO with this SSTR3 CLS-enhanced ciliary localization, compared with full-length RHO in IMCD3 and hTERT-RPE1 cells. Addition of the SSTR3 CLS to the single transmembrane protein CD8A enabled ciliary localization. In hTERT-RPE1 cells, a partial SSTR3 CLS added to CD8A effected specific localization to the periciliary (pocket) membrane, demonstrating C-terminal localization sequence targeting to this domain. Using retinas from mice, including both sexes, we show that deletion of the C terminus of RHO reduced the rod outer segment localization and that addition of the SSTR3 C-terminal CLS to the truncated RHO partly rescued this mislocalization. Overall, the study details elements of the different C termini of SSTR3 and RHO that are major effectors in determining specificity of cilium (or pericilium) localization among different types of cilia.SIGNIFICANCE STATEMENT The localization of G-protein-coupled receptors to primary cilia is key to many types of signal transduction. After characterizing a novel C-terminal CLS in SSTR3, we investigated how SSTR3 and RHO localization to the cilium relates to C-terminal CLSs and to cilium type. We found that the SSTR3 C-terminal CLS was effective in three different types of cilia, but the RHO C terminus showed a clear localization preference for the highly elaborate photoreceptor cilium. When added to CD8A, part of the SSTR3 CLS promoted specific periciliary membrane localization in hTERT-RPE1 cells, demonstrating an effective CLS for this domain. Thus, we demonstrate that elements of the C termini of SSTR3 and RHO determine different localization patterns among different types of cilia.
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Tůmová P, Voleman L, Klingl A, Nohýnková E, Wanner G, Doležal P. Inheritance of the reduced mitochondria of Giardia intestinalis is coupled to the flagellar maturation cycle. BMC Biol 2021; 19:193. [PMID: 34493257 PMCID: PMC8422661 DOI: 10.1186/s12915-021-01129-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 08/20/2021] [Indexed: 01/13/2023] Open
Abstract
Background The presence of mitochondria is a distinguishing feature between prokaryotic and eukaryotic cells. It is currently accepted that the evolutionary origin of mitochondria coincided with the formation of eukaryotes and from that point control of mitochondrial inheritance was required. Yet, the way the mitochondrial presence has been maintained throughout the eukaryotic cell cycle remains a matter of study. Eukaryotes control mitochondrial inheritance mainly due to the presence of the genetic component; still only little is known about the segregation of mitochondria to daughter cells during cell division. Additionally, anaerobic eukaryotic microbes evolved a variety of genomeless mitochondria-related organelles (MROs), which could be theoretically assembled de novo, providing a distinct mechanistic basis for maintenance of stable mitochondrial numbers. Here, we approach this problem by studying the structure and inheritance of the protist Giardia intestinalis MROs known as mitosomes. Results We combined 2D stimulated emission depletion (STED) microscopy and focused ion beam scanning electron microscopy (FIB/SEM) to show that mitosomes exhibit internal segmentation and conserved asymmetric structure. From a total of about forty mitosomes, a small, privileged population is harnessed to the flagellar apparatus, and their life cycle is coordinated with the maturation cycle of G. intestinalis flagella. The orchestration of mitosomal inheritance with the flagellar maturation cycle is mediated by a microtubular connecting fiber, which physically links the privileged mitosomes to both axonemes of the oldest flagella pair and guarantees faithful segregation of the mitosomes into the daughter cells. Conclusion Inheritance of privileged Giardia mitosomes is coupled to the flagellar maturation cycle. We propose that the flagellar system controls segregation of mitochondrial organelles also in other members of this supergroup (Metamonada) of eukaryotes and perhaps reflects the original strategy of early eukaryotic cells to maintain this key organelle before mitochondrial fusion-fission dynamics cycle as observed in Metazoa was established. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01129-7.
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Affiliation(s)
- Pavla Tůmová
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
| | - Luboš Voleman
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Andreas Klingl
- Plant Development and Electron Microscopy, Department of Biology I, Biocenter of Ludwig-Maximilians University, Munich, Germany
| | - Eva Nohýnková
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Gerhard Wanner
- Department of Biology I, Biocenter of Ludwig-Maximilians University, Munich, Germany
| | - Pavel Doležal
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic.
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Gorilak P, Pružincová M, Vachova H, Olšinová M, Schmidt Cernohorska M, Varga V. Expansion microscopy facilitates quantitative super-resolution studies of cytoskeletal structures in kinetoplastid parasites. Open Biol 2021; 11:210131. [PMID: 34465213 PMCID: PMC8437234 DOI: 10.1098/rsob.210131] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Expansion microscopy (ExM) has become a powerful super-resolution method in cell biology. It is a simple, yet robust approach, which does not require any instrumentation or reagents beyond those present in a standard microscopy facility. In this study, we used kinetoplastid parasites Trypanosoma brucei and Leishmania major, which possess a complex, yet well-defined microtubule-based cytoskeleton, to demonstrate that this method recapitulates faithfully morphology of structures as previously revealed by a combination of sophisticated electron microscopy (EM) approaches. Importantly, we also show that due to the rapidness of image acquisition and three-dimensional reconstruction of cellular volumes ExM is capable of complementing EM approaches by providing more quantitative data. This is demonstrated on examples of less well-appreciated microtubule structures, such as the neck microtubule of T. brucei or the pocket, cytosolic and multivesicular tubule-associated microtubules of L. major. We further demonstrate that ExM enables identifying cell types rare in a population, such as cells in mitosis and cytokinesis. Three-dimensional reconstruction of an entire volume of these cells provided details on the morphology of the mitotic spindle and the cleavage furrow. Finally, we show that established antibody markers of major cytoskeletal structures function well in ExM, which together with the ability to visualize proteins tagged with small epitope tags will facilitate studies of the kinetoplastid cytoskeleton.
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Affiliation(s)
- Peter Gorilak
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic,Charles University, Faculty of Science, Albertov 6, Prague, 128 00, Czech Republic
| | - Martina Pružincová
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Hana Vachova
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Marie Olšinová
- IMCF at BIOCEV, Faculty of Science, Charles University, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Marketa Schmidt Cernohorska
- Laboratory of Adaptive Immunity, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
| | - Vladimir Varga
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Vídeňská 1083, Prague, 14220, Czech Republic
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Link F, Borges AR, Jones NG, Engstler M. To the Surface and Back: Exo- and Endocytic Pathways in Trypanosoma brucei. Front Cell Dev Biol 2021; 9:720521. [PMID: 34422837 PMCID: PMC8377397 DOI: 10.3389/fcell.2021.720521] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/06/2021] [Indexed: 01/10/2023] Open
Abstract
Trypanosoma brucei is one of only a few unicellular pathogens that thrives extracellularly in the vertebrate host. Consequently, the cell surface plays a critical role in both immune recognition and immune evasion. The variant surface glycoprotein (VSG) coats the entire surface of the parasite and acts as a flexible shield to protect invariant proteins against immune recognition. Antigenic variation of the VSG coat is the major virulence mechanism of trypanosomes. In addition, incessant motility of the parasite contributes to its immune evasion, as the resulting fluid flow on the cell surface drags immunocomplexes toward the flagellar pocket, where they are internalized. The flagellar pocket is the sole site of endo- and exocytosis in this organism. After internalization, VSG is rapidly recycled back to the surface, whereas host antibodies are thought to be transported to the lysosome for degradation. For this essential step to work, effective machineries for both sorting and recycling of VSGs must have evolved in trypanosomes. Our understanding of the mechanisms behind VSG recycling and VSG secretion, is by far not complete. This review provides an overview of the trypanosome secretory and endosomal pathways. Longstanding questions are pinpointed that, with the advent of novel technologies, might be answered in the near future.
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Affiliation(s)
- Fabian Link
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Alyssa R Borges
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Nicola G Jones
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
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Structural and functional studies of the first tripartite protein complex at the Trypanosoma brucei flagellar pocket collar. PLoS Pathog 2021; 17:e1009329. [PMID: 34339455 PMCID: PMC8360560 DOI: 10.1371/journal.ppat.1009329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 08/12/2021] [Accepted: 07/04/2021] [Indexed: 11/19/2022] Open
Abstract
The flagellar pocket (FP) is the only endo- and exocytic organelle in most trypanosomes and, as such, is essential throughout the life cycle of the parasite. The neck of the FP is maintained enclosed around the flagellum via the flagellar pocket collar (FPC). The FPC is a macromolecular cytoskeletal structure and is essential for the formation of the FP and cytokinesis. FPC biogenesis and structure are poorly understood, mainly due to the lack of information on FPC composition. To date, only two FPC proteins, BILBO1 and FPC4, have been characterized. BILBO1 forms a molecular skeleton upon which other FPC proteins can, theoretically, dock onto. We previously identified FPC4 as the first BILBO1 interacting partner and demonstrated that its C-terminal domain interacts with the BILBO1 N-terminal domain (NTD). Here, we report by yeast two-hybrid, bioinformatics, functional and structural studies the characterization of a new FPC component and BILBO1 partner protein, BILBO2 (Tb927.6.3240). Further, we demonstrate that BILBO1 and BILBO2 share a homologous NTD and that both domains interact with FPC4. We have determined a 1.9 Å resolution crystal structure of the BILBO2 NTD in complex with the FPC4 BILBO1-binding domain. Together with mutational analyses, our studies reveal key residues for the function of the BILBO2 NTD and its interaction with FPC4 and evidenced a tripartite interaction between BILBO1, BILBO2, and FPC4. Our work sheds light on the first atomic structure of an FPC protein complex and represents a significant step in deciphering the FPC function in Trypanosoma brucei and other pathogenic kinetoplastids. Trypanosomes belong to a group of zoonotic, protist, parasites that are found in Africa, Asia, South America, and Europe and are responsible for severe human and animal diseases. They all have a common structure called the flagellar pocket (FP). In most trypanosomes, all macromolecular exchanges between the trypanosome and the environment occur via the FP. The FP is thus essential for cell viability and evading the host immune response. We have been studying the flagellar pocket collar (FPC), an enigmatic macromolecular structure at the neck of the FP, and demonstrated its essentiality for the biogenesis of the FP. We demonstrated that BILBO1 is an essential protein of the FPC that interacts with other proteins including a microtubule-binding protein FPC4. Here we identify another bona fide FPC protein, BILBO2, so named because of close similarity with BILBO1 in protein localization and functional domains. We demonstrate that BILBO1 and BILBO2 share a common N-terminal domain involved in the interaction with FPC4, and illustrate a tripartite interaction between BILBO1, BILBO2, and FPC4. Our study also provides the first atomic view of two FPC components. These data represent an additional step in deciphering the FPC structure and function in T. brucei.
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Campbell PC, de Graffenried CL. Alternate histories of cytokinesis: lessons from the trypanosomatids. Mol Biol Cell 2021; 31:2631-2639. [PMID: 33180676 PMCID: PMC7927182 DOI: 10.1091/mbc.e19-12-0696] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Popular culture has recently produced several “alternate histories” that describe worlds where key historical events had different outcomes. Beyond entertainment, asking “could this have happened a different way?” and “what would the consequences be?” are valuable approaches for exploring molecular mechanisms in many areas of research, including cell biology. Analogous to alternate histories, studying how the evolutionary trajectories of related organisms have been selected to provide a range of outcomes can tell us about the plasticity and potential contained within the genome of the ancestral cell. Among eukaryotes, a group of model organisms has been employed with great success to identify a core, conserved framework of proteins that segregate the duplicated cellular organelles into two daughter cells during cell division, a process known as cytokinesis. However, these organisms provide relatively sparse sampling across the broad evolutionary distances that exist, which has limited our understanding of the true potential of the ancestral eukaryotic toolkit. Recent work on the trypanosomatids, a group of eukaryotic parasites, exemplifies alternate historical routes for cytokinesis that illustrate the range of eukaryotic diversity, especially among unicellular organisms.
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Affiliation(s)
- Paul C Campbell
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
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24
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Dean S. Basic Biology of Trypanosoma brucei with Reference to the Development of Chemotherapies. Curr Pharm Des 2021; 27:1650-1670. [PMID: 33463458 DOI: 10.2174/1381612827666210119105008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 12/01/2020] [Accepted: 12/08/2020] [Indexed: 11/22/2022]
Abstract
Trypanosoma brucei are protozoan parasites that cause the lethal human disease African sleeping sickness and the economically devastating disease of cattle, Nagana. African sleeping sickness, also known as Human African Trypanosomiasis (HAT), threatens 65 million people and animal trypanosomiasis makes large areas of farmland unusable. There is no vaccine and licensed therapies against the most severe, late-stage disease are toxic, impractical and ineffective. Trypanosomes are transmitted by tsetse flies, and HAT is therefore predominantly confined to the tsetse fly belt in sub-Saharan Africa. They are exclusively extracellular and they differentiate between at least seven developmental forms that are highly adapted to host and vector niches. In the mammalian (human) host they inhabit the blood, cerebrospinal fluid (late-stage disease), skin, and adipose fat. In the tsetse fly vector they travel from the tsetse midgut to the salivary glands via the ectoperitrophic space and proventriculus. Trypanosomes are evolutionarily divergent compared with most branches of eukaryotic life. Perhaps most famous for their extraordinary mechanisms of monoallelic gene expression and antigenic variation, they have also been investigated because much of their biology is either highly unconventional or extreme. Moreover, in addition to their importance as pathogens, many researchers have been attracted to the field because trypanosomes have some of the most advanced molecular genetic tools and database resources of any model system. The following will cover just some aspects of trypanosome biology and how its divergent biochemistry has been leveraged to develop drugs to treat African sleeping sickness. This is by no means intended to be a comprehensive survey of trypanosome features. Rather, I hope to present trypanosomes as one of the most fascinating and tractable systems to do discovery biology.
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Affiliation(s)
- Samuel Dean
- Warwick Medical School, University of Warwick, Coventry, CV4 7AL, United Kingdom
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25
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Corrales RM, Vaselek S, Neish R, Berry L, Brunet CD, Crobu L, Kuk N, Mateos-Langerak J, Robinson DR, Volf P, Mottram JC, Sterkers Y, Bastien P. The kinesin of the flagellum attachment zone in Leishmania is required for cell morphogenesis, cell division and virulence in the mammalian host. PLoS Pathog 2021; 17:e1009666. [PMID: 34143858 PMCID: PMC8244899 DOI: 10.1371/journal.ppat.1009666] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 06/30/2021] [Accepted: 05/24/2021] [Indexed: 11/20/2022] Open
Abstract
Leishmania parasites possess a unique and complex cytoskeletal structure termed flagellum attachment zone (FAZ) connecting the base of the flagellum to one side of the flagellar pocket (FP), an invagination of the cell body membrane and the sole site for endocytosis and exocytosis. This structure is involved in FP architecture and cell morphogenesis, but its precise role and molecular composition remain enigmatic. Here, we characterized Leishmania FAZ7, the only known FAZ protein containing a kinesin motor domain, and part of a clade of trypanosomatid-specific kinesins with unknown functions. The two paralogs of FAZ7, FAZ7A and FAZ7B, display different localizations and functions. FAZ7A localizes at the basal body, while FAZ7B localizes at the distal part of the FP, where the FAZ structure is present in Leishmania. While null mutants of FAZ7A displayed normal growth rates, the deletion of FAZ7B impaired cell growth in both promastigotes and amastigotes of Leishmania. The kinesin activity is crucial for its function. Deletion of FAZ7B resulted in altered cell division, cell morphogenesis (including flagellum length), and FP structure and function. Furthermore, knocking out FAZ7B induced a mis-localization of two of the FAZ proteins, and disrupted the molecular organization of the FP collar, affecting the localization of its components. Loss of the kinesin FAZ7B has important consequences in the insect vector and mammalian host by reducing proliferation in the sand fly and pathogenicity in mice. Our findings reveal the pivotal role of the only FAZ kinesin as part of the factors important for a successful life cycle of Leishmania. Leishmania are flagellated trypanosomatid parasites causing worldwide human and animal diseases. As ’divergent eukaryotes’, their biology presents unique features and structures, of which the specific functions constitute potential drug targets. Among others, they possess a unique cytoskeletal structure termed the flagellum attachment zone (FAZ) attaching the base of their flagellum to one side of the flagellar pocket (FP), which is the sole site for endocytosis and exocytosis. The FP together with other unique flagellum-associated structures are crucial for parasite survival, but the functioning of this whole remains largely enigmatic. Leishmania also possess an expanded repertoire of kinesins (>55), including two trypanosomatid-specific families. Here, we show that the deletion of the sole kinesin among FAZ proteins disrupts cell morphogenesis, FP organisation and cell division. Furthermore, the ability to proliferate in the insect vector and mammalian host is reduced in parasites lacking the kinesin FAZ7B. This study helps elucidate the factors contributing to the successful lifecycle and pathogenicity of the parasite. It also highlights the functional diversification of motor proteins during evolution.
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Affiliation(s)
- Rosa Milagros Corrales
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
- * E-mail: (RMC); (PB)
| | - Slavica Vaselek
- Department of Parasitology, Charles University, Prague, Czech Republic
| | - Rachel Neish
- York Biomedical Research Institute and Department of Biology, University of York, York, United Kingdom
| | - Laurence Berry
- Research Unit “LPHI” (Laboratory of Pathogen Host Interactions), University of Montpellier, CNRS, Montpellier, France
| | - Camille D. Brunet
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
| | - Lucien Crobu
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
| | - Nada Kuk
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
| | | | - Derrick R. Robinson
- Research Unit “Fundamental Microbiology and Pathogenicity”, “Protist Parasite Cytoskeleton (ProParaCyto)”, University of Bordeaux, UMR 5234, CNRS, Bordeaux, France
| | - Petr Volf
- Department of Parasitology, Charles University, Prague, Czech Republic
| | - Jeremy C. Mottram
- York Biomedical Research Institute and Department of Biology, University of York, York, United Kingdom
| | - Yvon Sterkers
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
| | - Patrick Bastien
- Research Unit “MiVEGEC”, University of Montpellier, CNRS, IRD, Academic Hospital (CHU) of Montpellier, Montpellier, France
- * E-mail: (RMC); (PB)
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26
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Stepinac E, Landrein N, Skwarzyńska D, Wójcik P, Lesigang J, Lučić I, He CY, Bonhivers M, Robinson DR, Dong G. Structural studies of the shortest extended synaptotagmin with only two C2 domains from Trypanosoma brucei. iScience 2021; 24:102422. [PMID: 33997700 PMCID: PMC8093936 DOI: 10.1016/j.isci.2021.102422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/03/2021] [Accepted: 04/08/2021] [Indexed: 11/25/2022] Open
Abstract
Extended synaptotagmins (E-Syts) localize at membrane contact sites between the endoplasmic reticulum (ER) and the plasma membrane to mediate inter-membrane lipid transfer and control plasma membrane lipid homeostasis. All known E-Syts contain an N-terminal transmembrane (TM) hairpin, a central synaptotagmin-like mitochondrial lipid-binding protein (SMP) domain, and three or five C2 domains at their C termini. Here we report an uncharacterized E-Syt from the protist parasite Trypanosoma brucei, namely, TbE-Syt. TbE-Syt contains only two C2 domains (C2A and C2B), making it the shortest E-Syt known by now. We determined a 1.5-Å-resolution crystal structure of TbE-Syt-C2B and revealed that it binds lipids via both Ca2+- and PI(4,5)P2-dependent means. In contrast, TbE-Syt-C2A lacks the Ca2+-binding site but may still interact with lipids via a basic surface patch. Our studies suggest a mechanism for how TbE-Syt tethers the ER membrane tightly to the plasma membrane to transfer lipids between the two organelles. We identified a new type of extended synaptotagmin (E-Syt) in Trypanosoma brucei TbE-Syt is the shortest known E-Syt with only two C2 domains, C2A and C2B TbE-Syt-C2B binds lipids via both Ca2+- and PI(4,5)P2-dependent means Unlike all other known E-Syts, TbE-Syt-C2A and C2B are connected by a flexible loop
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Affiliation(s)
- Emma Stepinac
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
| | - Nicolas Landrein
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33000 Bordeaux, France
| | - Daria Skwarzyńska
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria.,Silesian University of Technology, Gliwice, Poland
| | - Patrycja Wójcik
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria.,Silesian University of Technology, Gliwice, Poland
| | - Johannes Lesigang
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
| | - Iva Lučić
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
| | - Cynthia Y He
- Department of Biological Sciences, Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Mélanie Bonhivers
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33000 Bordeaux, France
| | - Derrick R Robinson
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, 33000 Bordeaux, France
| | - Gang Dong
- Max Perutz Labs, Vienna Biocenter, Center for Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
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27
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Halliday C, de Castro-Neto A, Alcantara CL, Cunha-E-Silva NL, Vaughan S, Sunter JD. Trypanosomatid Flagellar Pocket from Structure to Function. Trends Parasitol 2021; 37:317-329. [PMID: 33308952 DOI: 10.1016/j.pt.2020.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023]
Abstract
The trypanosomatids Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. are flagellate eukaryotic parasites that cause serious diseases in humans and animals. These parasites have cell shapes defined by a subpellicular microtubule array and all share a number of important cellular features. One of these is the flagellar pocket, an invagination of the cell membrane around the proximal end of the flagellum, which is an important organelle for endo/exocytosis. The flagellar pocket plays a crucial role in parasite pathogenicity and persistence in the host and has a great influence on cell morphogenesis and cell division. Here, we compare the morphology and function of the flagellar pockets between different trypanosomatids, with their life cycles and ecological niches likely influencing these differences.
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Affiliation(s)
- Clare Halliday
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Artur de Castro-Neto
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Carolina L Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Narcisa L Cunha-E-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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28
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Melo do Nascimento L, Egler F, Arnold K, Papavasiliou N, Clayton C, Erben E. Functional insights from a surface antigen mRNA-bound proteome. eLife 2021; 10:e68136. [PMID: 33783358 PMCID: PMC8051951 DOI: 10.7554/elife.68136] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/18/2021] [Indexed: 01/13/2023] Open
Abstract
Trypanosoma brucei is the causative agent of human sleeping sickness. The parasites' variant surface glycoprotein (VSG) enables them to evade adaptive immunity via antigenic variation. VSG comprises 10% of total cell protein and the high stability of VSG mRNA is essential for trypanosome survival. To determine how VSG mRNA stability is maintained, we used mRNA affinity purification to identify all its associated proteins. CFB2 (cyclin F-box protein 2), an unconventional RNA-binding protein with an F-box domain, was specifically enriched with VSG mRNA. We demonstrate that CFB2 is essential for VSG mRNA stability, describe cis acting elements within the VSG 3'-untranslated region that regulate the interaction, identify trans-acting factors that are present in the VSG messenger ribonucleoprotein particle, and mechanistically explain how CFB2 stabilizes the mRNA of this key pathogenicity factor. Beyond T. brucei, the mRNP purification approach has the potential to supply detailed biological insight into metabolism of relatively abundant mRNAs in any eukaryote.
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Affiliation(s)
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Katharina Arnold
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Nina Papavasiliou
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Esteban Erben
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
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29
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Abstract
All living cells interact dynamically with a constantly changing world. Eukaryotes, in particular, evolved radically new ways to sense and react to their environment. These advances enabled new and more complex forms of cellular behaviour in eukaryotes, including directional movement, active feeding, mating, and responses to predation. But what are the key events and innovations during eukaryogenesis that made all of this possible? Here we describe the ancestral repertoire of eukaryotic excitability and discuss five major cellular innovations that enabled its evolutionary origin. The innovations include a vastly expanded repertoire of ion channels, the emergence of cilia and pseudopodia, endomembranes as intracellular capacitors, a flexible plasma membrane and the relocation of chemiosmotic ATP synthesis to mitochondria, which liberated the plasma membrane for more complex electrical signalling involved in sensing and reacting. We conjecture that together with an increase in cell size, these new forms of excitability greatly amplified the degrees of freedom associated with cellular responses, allowing eukaryotes to vastly outperform prokaryotes in terms of both speed and accuracy. This comprehensive new perspective on the evolution of excitability enriches our view of eukaryogenesis and emphasizes behaviour and sensing as major contributors to the success of eukaryotes. This article is part of the theme issue 'Basal cognition: conceptual tools and the view from the single cell'.
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Affiliation(s)
- Kirsty Y. Wan
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
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30
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Sajko S, Grishkovskaya I, Kostan J, Graewert M, Setiawan K, Trübestein L, Niedermüller K, Gehin C, Sponga A, Puchinger M, Gavin AC, Leonard TA, Svergun DI, Smith TK, Morriswood B, Djinovic-Carugo K. Structures of three MORN repeat proteins and a re-evaluation of the proposed lipid-binding properties of MORN repeats. PLoS One 2020; 15:e0242677. [PMID: 33296386 PMCID: PMC7725318 DOI: 10.1371/journal.pone.0242677] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 11/08/2020] [Indexed: 11/19/2022] Open
Abstract
MORN (Membrane Occupation and Recognition Nexus) repeat proteins have a wide taxonomic distribution, being found in both prokaryotes and eukaryotes. Despite this ubiquity, they remain poorly characterised at both a structural and a functional level compared to other common repeats. In functional terms, they are often assumed to be lipid-binding modules that mediate membrane targeting. We addressed this putative activity by focusing on a protein composed solely of MORN repeats-Trypanosoma brucei MORN1. Surprisingly, no evidence for binding to membranes or lipid vesicles by TbMORN1 could be obtained either in vivo or in vitro. Conversely, TbMORN1 did interact with individual phospholipids. High- and low-resolution structures of the MORN1 protein from Trypanosoma brucei and homologous proteins from the parasites Toxoplasma gondii and Plasmodium falciparum were obtained using a combination of macromolecular crystallography, small-angle X-ray scattering, and electron microscopy. This enabled a first structure-based definition of the MORN repeat itself. Furthermore, all three structures dimerised via their C-termini in an antiparallel configuration. The dimers could form extended or V-shaped quaternary structures depending on the presence of specific interface residues. This work provides a new perspective on MORN repeats, showing that they are protein-protein interaction modules capable of mediating both dimerisation and oligomerisation.
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Affiliation(s)
- Sara Sajko
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Irina Grishkovskaya
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Julius Kostan
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Melissa Graewert
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Kim Setiawan
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Linda Trübestein
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Korbinian Niedermüller
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Charlotte Gehin
- European Molecular Biology Laboratory, Heidelberg Unit, Heidelberg, Germany
- Institute of Bioengineering, Laboratory of Lipid Cell Biology, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Antonio Sponga
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Martin Puchinger
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | - Anne-Claude Gavin
- European Molecular Biology Laboratory, Heidelberg Unit, Heidelberg, Germany
- Department for Cell Physiology and Metabolism, University of Geneva, Centre Medical Universitaire, Geneva, Switzerland
| | - Thomas A. Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | - Terry K. Smith
- School of Biology, BSRC, University of St. Andrews, St. Andrews, United Kingdom
| | - Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Kristina Djinovic-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
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31
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Trépout S. In situ structural analysis of the flagellum attachment zone in Trypanosoma brucei using cryo-scanning transmission electron tomography. JOURNAL OF STRUCTURAL BIOLOGY-X 2020; 4:100033. [PMID: 32775999 PMCID: PMC7394968 DOI: 10.1016/j.yjsbx.2020.100033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/06/2020] [Accepted: 07/16/2020] [Indexed: 11/26/2022]
Abstract
Flagellar and cellular membranes are in close contact next to the FAZ filament. Sticks are heterogeneously distributed along the FAZ filament length. Thin appendages are present between the sticks and the neighbouring microtubules. The FAZ could elongate thanks to the action of dynein on subpellicular microtubules.
The flagellum of Trypanosoma brucei is a 20 µm-long organelle responsible for locomotion and cell morphogenesis. The flagellum attachment zone (FAZ) is a multi-protein complex whose function is to attach the flagellum to the cell body but also to guide cytokinesis. Cryo-transmission electron microscopy is a tool of choice to access the structure of the FAZ in a close-to-native state. However, because of the large dimension of the cell body, the whole FAZ cannot be structurally studied in situ at the nanometre scale in 3D using classical transmission electron microscopy approaches. In the present work, cryo-scanning transmission electron tomography, a new method capable of investigating cryo-fixed thick biological samples, has been used to study whole T. brucei cells at the bloodstream stage. The method has been used to visualise and characterise the structure and organisation of the FAZ filament. It is composed of an array of cytoplasmic stick-like structures. These sticks are heterogeneously distributed between the posterior part and the anterior tip of the cell. This cryo-STET investigation provides new insights into the structure of the FAZ filament. In combination with protein structure predictions, this work proposes a new model for the elongation of the FAZ.
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32
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Douglas RL, Haltiwanger BM, Albisetti A, Wu H, Jeng RL, Mancuso J, Cande WZ, Welch MD. Trypanosomes have divergent kinesin-2 proteins that function differentially in flagellum biosynthesis and cell viability. J Cell Sci 2020; 133:jcs129213. [PMID: 32503938 DOI: 10.1242/jcs.129213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
Trypanosoma brucei, the causative agent of African sleeping sickness, has a flagellum that is crucial for motility, pathogenicity, and viability. In most eukaryotes, the intraflagellar transport (IFT) machinery drives flagellum biogenesis, and anterograde IFT requires kinesin-2 motor proteins. In this study, we investigated the function of the two T. brucei kinesin-2 proteins, TbKin2a and TbKin2b, in bloodstream form trypanosomes. We found that, compared to kinesin-2 proteins across other phyla, TbKin2a and TbKin2b show greater variation in neck, stalk and tail domain sequences. Both kinesins contributed additively to flagellar lengthening. Silencing TbKin2a inhibited cell proliferation, cytokinesis and motility, whereas silencing TbKin2b did not. TbKin2a was localized on the flagellum and colocalized with IFT components near the basal body, consistent with it performing a role in IFT. TbKin2a was also detected on the flagellar attachment zone, a specialized structure that connects the flagellum to the cell body. Our results indicate that kinesin-2 proteins in trypanosomes play conserved roles in flagellar biosynthesis and exhibit a specialized localization, emphasizing the evolutionary flexibility of motor protein function in an organism with a large complement of kinesins.
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Affiliation(s)
- Robert L Douglas
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Brett M Haltiwanger
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Anna Albisetti
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Haiming Wu
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Robert L Jeng
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Joel Mancuso
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - W Zacheus Cande
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
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33
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Basal Body Protein TbSAF1 Is Required for Microtubule Quartet Anchorage to the Basal Bodies in Trypanosoma brucei. mBio 2020; 11:mBio.00668-20. [PMID: 32518185 PMCID: PMC7291619 DOI: 10.1128/mbio.00668-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Trypanosoma brucei contains a large array of single-copied organelles and structures. Through extensive interorganelle connections, these structures replicate and divide following a strict temporal and spatial order. A microtubule quartet (MtQ) originates from the basal bodies and extends toward the anterior end of the cell, stringing several cytoskeletal structures together along its path. In this study, we examined the interaction network of TbSpef1, the only protein specifically located to the MtQ. We identified an interaction between TbSpef1 and a basal body protein TbSAF1, which is required for MtQ anchorage to the basal bodies. This study thus provides the first molecular description of MtQ association with the basal bodies, since the discovery of this association ∼30 years ago. The results also reveal a general mechanism of the evolutionarily conserved Spef1/CLAMP, which achieves specific cellular functions via their conserved microtubule functions and their diverse molecular interaction networks. Sperm flagellar protein 1 (Spef1, also known as CLAMP) is a microtubule-associated protein involved in various microtubule-related functions from ciliary motility to polarized cell movement and planar cell polarity. In Trypanosoma brucei, the causative agent of trypanosomiasis, a single Spef1 ortholog (TbSpef1) is associated with a microtubule quartet (MtQ), which is in close association with several single-copied organelles and is required for their coordinated biogenesis during the cell cycle. Here, we investigated the interaction network of TbSpef1 using BioID, a proximity-dependent protein-protein interaction screening method. Characterization of selected candidates provided a molecular description of TbSpef1-MtQ interactions with nearby cytoskeletal structures. Of particular interest, we identified a new basal body protein TbSAF1, which is required for TbSpef1-MtQ anchorage to the basal bodies. The results demonstrate that MtQ-basal body anchorage is critical for the spatial organization of cytoskeletal organelles, as well as the morphology of the membrane-bound flagellar pocket where endocytosis takes place in this parasite.
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Lemos M, Mallet A, Bertiaux E, Imbert A, Rotureau B, Bastin P. Timing and original features of flagellum assembly in trypanosomes during development in the tsetse fly. Parasit Vectors 2020; 13:169. [PMID: 32248844 PMCID: PMC7132888 DOI: 10.1186/s13071-020-04026-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/17/2020] [Indexed: 02/07/2023] Open
Abstract
Background Trypanosoma brucei exhibits a complex life-cycle alternating between tsetse flies and mammalian hosts. When parasites infect the fly, cells differentiate to adapt to life in various tissues, which is accompanied by drastic morphological and biochemical modifications especially in the proventriculus. This key step represents a bottleneck for salivary gland infection. Methods Here, we monitored flagellum assembly in trypanosomes during differentiation from the trypomastigote to the epimastigote stage, i.e. when the nucleus migrates to the posterior end of the cell, by using three-dimensional electron microscopy (focused ion beam scanning electron microscopy, FIB-SEM) and immunofluorescence assays. Results The combination of light and electron microscopy approaches provided structural and molecular evidence that the new flagellum is assembled while the nucleus migrates towards the posterior region of the body. Two major differences with well-known procyclic cells are reported. First, growth of the new flagellum begins when the associated basal body is found in a posterior position relative to the mature flagellum. Secondly, the new flagellum acquires its own flagellar pocket before rotating on the left side of the anterior-posterior axis. FIB-SEM revealed the presence of a structure connecting the new and mature flagellum and serial sectioning confirmed morphological similarities with the flagella connector of procyclic cells. We discuss the potential function of the flagella connector in trypanosomes from the proventriculus. Conclusions These findings show that T. brucei finely modulates its cytoskeletal components to generate highly variable morphologies.![]()
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Affiliation(s)
- Moara Lemos
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France
| | - Adeline Mallet
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.,UtechS Ultrastructural Bioimaging (Ultrapole), C2RT, Institut Pasteur, 75015, Paris, France.,Sorbonne Université école doctorale Complexité du Vivant, ED 515, 7, quai Saint-Bernard, case 32, 75252, Paris Cedex 05, France
| | - Eloïse Bertiaux
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.,Sorbonne Université école doctorale Complexité du Vivant, ED 515, 7, quai Saint-Bernard, case 32, 75252, Paris Cedex 05, France
| | | | - Brice Rotureau
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.
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Motta MCM, Catta-Preta CMC. Electron Microscopy Techniques Applied to Symbiont-Harboring Trypanosomatids: The Association of the Bacterium with Host Organelles. Methods Mol Biol 2020; 2116:425-447. [PMID: 32221935 DOI: 10.1007/978-1-0716-0294-2_26] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In this chapter we describe different electron microscopy techniques such as freeze fracture, deep etching, and three-dimensional reconstruction, obtained by electron tomography or focused ion beam scanning electron microscopy (FIB-SEM), combined with quick-freezing methods in order to reveal aspects of the cell structure in trypanosomatids. For this purpose, we chose protists that evolve in a mutualistic way with a symbiotic bacterium. Such cells represent excellent models to study the positioning and distribution of organelles, since the symbiotic bacterium interacts with different organelles of the host trypanosomatid. We demonstrate that the employment of such techniques can show the proximity and even the interaction of the symbiotic bacterium with different structures of the protist host, such as the nucleus and the glycosomes. In addition, the quick-freezing approach can reveal new aspects of the gram-negative bacterial envelope, such as the presence of a greatly reduced cell wall between the two membrane units.
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Affiliation(s)
- Maria Cristina M Motta
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
| | - Carolina M C Catta-Preta
- Centro de Química Medicinal (CQMED)/Structural Genomics Consortium (SGC), Universidade Estadual de Campinas, São Paulo, Brazil
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Wang Z, Wheeler RJ, Sunter JD. Lysosome assembly and disassembly changes endocytosis rate through the Leishmania cell cycle. Microbiologyopen 2019; 9:e969. [PMID: 31743959 PMCID: PMC7002101 DOI: 10.1002/mbo3.969] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 01/03/2023] Open
Abstract
The Leishmania lysosome has an atypical structure, consisting of an elongated vesicle‐filled tubule running along the anterior–posterior axis of the cell, which is termed the multivesicular tubule (MVT) lysosome. Alongside, the MVT lysosome is one or more microtubules, the lysosomal microtubule(s). Previous work indicated there were cell cycle‐related changes in MVT lysosome organization; however, these only provided snapshots and did not connect the changes in the lysosomal microtubule(s) or lysosomal function. Using mNeonGreen tagged cysteine peptidase A and SPEF1 as markers of the MVT lysosome and lysosomal microtubule(s), we examined the dynamics of these structures through the cell cycle. Both the MVT lysosome and lysosomal microtubule(s) elongated at the beginning of the cell cycle before plateauing and then disassembling in late G2 before cytokinesis. Moreover, the endocytic rate in cells where the MVT lysosome and lysosomal microtubule(s) had disassembled was extremely low. The dynamic nature of the MVT lysosome and lysosomal microtubule(s) parallels that of the Trypanosoma cruzi cytostome/cytopharynx, which also has a similar membrane tubule structure with associated microtubules. As the cytostome/cytopharynx is an ancestral feature of the kinetoplastids, this suggests that the Leishmania MVT lysosome and lysosomal microtubule(s) are a reduced cytostome/cytopharynx‐like feature.
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Affiliation(s)
- Ziyin Wang
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Richard J Wheeler
- The Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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Sinclair AN, de Graffenried CL. More than Microtubules: The Structure and Function of the Subpellicular Array in Trypanosomatids. Trends Parasitol 2019; 35:760-777. [PMID: 31471215 PMCID: PMC6783356 DOI: 10.1016/j.pt.2019.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
Abstract
The subpellicular microtubule array defines the wide range of cellular morphologies found in parasitic kinetoplastids (trypanosomatids). Morphological studies have characterized array organization, but little progress has been made towards identifying the molecular mechanisms that are responsible for array differentiation during the trypanosomatid life cycle, or the apparent stability and longevity of array microtubules. In this review, we outline what is known about the structure and biogenesis of the array, with emphasis on Trypanosoma brucei, Trypanosoma cruzi, and Leishmania, which cause life-threatening diseases in humans and livestock. We highlight unanswered questions about this remarkable cellular structure that merit new consideration in light of our recently improved understanding of how the 'tubulin code' influences microtubule dynamics to generate complex cellular structures.
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Affiliation(s)
- Amy N Sinclair
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
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Abstract
Trypanosomes have complex life cycles within which there are both proliferative and differentiation cell divisions. The coordination of the cell cycle to achieve these different divisions is critical for the parasite to infect both host and vector. From studying the regulation of the proliferative cell cycle of the Trypanosoma brucei procyclic life cycle stage, three subcycles emerge that control the duplication and segregation of ( a) the nucleus, ( b) the kinetoplast, and ( c) a set of cytoskeletal structures. We discuss how the clear dependency relationships within these subcycles, and the potential for cross talk between them, are likely required for overall cell cycle coordination. Finally, we look at the implications this interdependence has for proliferative and differentiation divisions through the T. brucei life cycle and in related parasitic trypanosomatid species.
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Affiliation(s)
- Richard J. Wheeler
- Nuffield Department of Medicine, University of Oxford, Oxford OX1 3SY, United Kingdom
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Jack D. Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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Spreng B, Fleckenstein H, Kübler P, Di Biagio C, Benz M, Patra P, Schwarz US, Cyrklaff M, Frischknecht F. Microtubule number and length determine cellular shape and function in Plasmodium. EMBO J 2019; 38:e100984. [PMID: 31368598 PMCID: PMC6669926 DOI: 10.15252/embj.2018100984] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/12/2019] [Accepted: 04/26/2019] [Indexed: 11/27/2022] Open
Abstract
Microtubules are cytoskeletal filaments essential for many cellular processes, including establishment and maintenance of polarity, intracellular transport, division and migration. In most metazoan cells, the number and length of microtubules are highly variable, while they can be precisely defined in some protozoan organisms. However, in either case the significance of these two key parameters for cells is not known. Here, we quantitatively studied the impact of modulating microtubule number and length in Plasmodium, the protozoan parasite causing malaria. Using a gene deletion and replacement strategy targeting one out of two α-tubulin genes, we show that chromosome segregation proceeds in the oocysts even in the absence of microtubules. However, fewer and shorter microtubules severely impaired the formation, motility and infectivity of Plasmodium sporozoites, the forms transmitted by the mosquito, which usually contain 16 microtubules. We found that α-tubulin expression levels directly determined the number of microtubules, suggesting a high nucleation barrier as supported by a mathematical model. Infectious sporozoites were only formed in parasite lines featuring at least 10 microtubules, while parasites with 9 or fewer microtubules failed to transmit.
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Affiliation(s)
- Benjamin Spreng
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Hannah Fleckenstein
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Patrick Kübler
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Claudia Di Biagio
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Madlen Benz
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Pintu Patra
- Institute for Theoretical Physics and BioquantHeidelberg UniversityHeidelbergGermany
| | - Ulrich S Schwarz
- Institute for Theoretical Physics and BioquantHeidelberg UniversityHeidelbergGermany
| | - Marek Cyrklaff
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
| | - Friedrich Frischknecht
- Integrative ParasitologyCenter for Infectious DiseasesHeidelberg University Medical SchoolHeidelbergGermany
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Leishmania flagellum attachment zone is critical for flagellar pocket shape, development in the sand fly, and pathogenicity in the host. Proc Natl Acad Sci U S A 2019; 116:6351-6360. [PMID: 30850532 PMCID: PMC6442623 DOI: 10.1073/pnas.1812462116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Leishmania alternates between an insect vector and human host; in these different environments, the parasite adopts different forms. There are important commonalities between these different forms, particularly the flagellar pocket (FP) and associated flagellum attachment zone (FAZ). We show that the FAZ is important in different forms of Leishmania for FP shape and function, which are altered in mutants lacking a FAZ protein, FAZ5. FAZ5 deletion did not affect parasite proliferation and differentiation in culture; however, it dramatically reduced parasite proliferation in the sand fly and mouse. These results demonstrate the importance of the FAZ for FP function and architecture, and show that deletion of one FAZ protein can have a dramatic effect on Leishmania development and pathogenicity. Leishmania kinetoplastid parasites infect millions of people worldwide and have a distinct cellular architecture depending on location in the host or vector and specific pathogenicity functions. An invagination of the cell body membrane at the base of the flagellum, the flagellar pocket (FP), is an iconic kinetoplastid feature, and is central to processes that are critical for Leishmania pathogenicity. The Leishmania FP has a bulbous region posterior to the FP collar and a distal neck region where the FP membrane surrounds the flagellum more closely. The flagellum is attached to one side of the FP neck by the short flagellum attachment zone (FAZ). We addressed whether targeting the FAZ affects FP shape and its function as a platform for host–parasite interactions. Deletion of the FAZ protein, FAZ5, clearly altered FP architecture and had a modest effect in endocytosis but did not compromise cell proliferation in culture. However, FAZ5 deletion had a dramatic impact in vivo: Mutants were unable to develop late-stage infections in sand flies, and parasite burdens in mice were reduced by >97%. Our work demonstrates the importance of the FAZ for FP function and architecture. Moreover, we show that deletion of a single FAZ protein can have a large impact on parasite development and pathogenicity.
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Halliday C, Billington K, Wang Z, Madden R, Dean S, Sunter JD, Wheeler RJ. Cellular landmarks of Trypanosoma brucei and Leishmania mexicana. Mol Biochem Parasitol 2018; 230:24-36. [PMID: 30550896 PMCID: PMC6529878 DOI: 10.1016/j.molbiopara.2018.12.003] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 11/29/2022]
Abstract
Trypanosoma and Leishmania are single cell eukaryotic parasites. The cell organisation of these human pathogens is complex and highly structured. This describes an inventory of reliable reference markers for 32 cell structures. These light microscopy landmarks are a valuable resource for researchers.
The kinetoplastids Trypanosoma brucei and Leishmania mexicana are eukaryotes with a highly structured cellular organisation that is reproduced with great fidelity in each generation. The pattern of signal from a fluorescently tagged protein can define the specific structure/organelle that this protein localises to, and can be extremely informative in phenotype analysis in experimental perturbations, life cycle tracking, post-genomic assays and functional analysis of organelles. Using the vast coverage of protein subcellular localisations provided by the TrypTag project, an ongoing project to determine the localisation of every protein encoded in the T. brucei genome, we have generated an inventory of reliable reference organelle markers for both parasites that combines epifluorescence images with a detailed description of the key features of each localisation. We believe this will be a useful comparative resource that will enable researchers to quickly and accurately pinpoint the localisation of their proteins of interest and will provide cellular markers for many types of cell biology studies. We see this as another important step in the post-genomic era analyses of these parasites, in which ever expanding datasets generate numerous candidates to analyse. Adoption of these reference proteins by the community is likely to enhance research studies and enable better comparison of data.
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Affiliation(s)
- Clare Halliday
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK; Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK
| | - Karen Billington
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Ziyin Wang
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Ross Madden
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Samuel Dean
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK.
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford, OX3 0BP, UK.
| | - Richard John Wheeler
- The Peter Medawar Building for Pathogen Research, University of Oxford, South Parks Road, Oxford, OX1 3SY, UK.
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Sunter JD, Moreira-Leite F, Gull K. Dependency relationships between IFT-dependent flagellum elongation and cell morphogenesis in Leishmania. Open Biol 2018; 8:rsob.180124. [PMID: 30463910 PMCID: PMC6282073 DOI: 10.1098/rsob.180124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/26/2018] [Indexed: 01/03/2023] Open
Abstract
Flagella have multiple functions that are associated with different axonemal structures. Motile flagella typically have a 9 + 2 arrangement of microtubules, whereas sensory flagella normally have a 9 + 0 arrangement. Leishmania exhibits both of these flagellum forms and differentiation between these two flagellum forms is associated with cytoskeletal and cell shape changes. We disrupted flagellum elongation in Leishmania by deleting the intraflagellar transport (IFT) protein IFT140 and examined the effects on cell morphogenesis. Δift140 cells have no external flagellum, having only a very short flagellum within the flagellar pocket. This short flagellum had a collapsed 9 + 0 (9v) axoneme configuration reminiscent of that in the amastigote and was not attached to the pocket membrane. Although amastigote-like changes occurred in the flagellar cytoskeleton, the cytoskeletal structures of Δift140 cells retained their promastigote configurations, as examined by fluorescence microscopy of tagged proteins and serial electron tomography. Thus, Leishmania promastigote cell morphogenesis does not depend on the formation of a long flagellum attached at the neck. Furthermore, our data show that disruption of the IFT system is sufficient to produce a switch from the 9 + 2 to the collapsed 9 + 0 (9v) axonemal structure, echoing the process that occurs during the promastigote to amastigote differentiation.
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Affiliation(s)
- Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Flavia Moreira-Leite
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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Boundary behaviours of Leishmania mexicana: A hydrodynamic simulation study. J Theor Biol 2018; 462:311-320. [PMID: 30465777 PMCID: PMC6333917 DOI: 10.1016/j.jtbi.2018.11.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023]
Abstract
It is well established that the parasites of the genus Leishmania exhibit complex surface interactions with the sandfly vector midgut epithelium, but no prior study has considered the details of their hydrodynamics. Here, the boundary behaviours of motile Leishmania mexicana promastigotes are explored in a computational study using the boundary element method, with a model flagellar beating pattern that has been identified from digital videomicroscopy. In particular a simple flagellar kinematics is observed and quantified using image processing and mode identification techniques, suggesting a simple mechanical driver for the Leishmania beat. Phase plane analysis and long-time simulation of a range of Leishmania swimming scenarios demonstrate an absence of stable boundary motility for an idealised model promastigote, with behaviours ranging from boundary capture to deflection into the bulk both with and without surface forces between the swimmer and the boundary. Indeed, the inclusion of a short-range repulsive surface force results in the deflection of all surface-bound promastigotes, suggesting that the documented surface detachment of infective metacyclic promastigotes may be the result of their particular morphology and simple hydrodynamics. Further, simulation elucidates a remarkable morphology-dependent hydrodynamic mechanism of boundary approach, hypothesised to be the cause of the well-established phenomenon of tip-first epithelial attachment of Leishmania promastigotes to the sandfly vector midgut.
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Bonnefoy S, Watson CM, Kernohan KD, Lemos M, Hutchinson S, Poulter JA, Crinnion LA, Berry I, Simmonds J, Vasudevan P, O'Callaghan C, Hirst RA, Rutman A, Huang L, Hartley T, Grynspan D, Moya E, Li C, Carr IM, Bonthron DT, Leroux M, Boycott KM, Bastin P, Sheridan EG. Biallelic Mutations in LRRC56, Encoding a Protein Associated with Intraflagellar Transport, Cause Mucociliary Clearance and Laterality Defects. Am J Hum Genet 2018; 103:727-739. [PMID: 30388400 PMCID: PMC6218757 DOI: 10.1016/j.ajhg.2018.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 10/01/2018] [Indexed: 01/15/2023] Open
Abstract
Primary defects in motile cilia result in dysfunction of the apparatus responsible for generating fluid flows. Defects in these mechanisms underlie disorders characterized by poor mucus clearance, resulting in susceptibility to chronic recurrent respiratory infections, often associated with infertility; laterality defects occur in about 50% of such individuals. Here we report biallelic variants in LRRC56 (known as oda8 in Chlamydomonas) identified in three unrelated families. The phenotype comprises laterality defects and chronic pulmonary infections. High-speed video microscopy of cultured epithelial cells from an affected individual showed severely dyskinetic cilia but no obvious ultra-structural abnormalities on routine transmission electron microscopy (TEM). Further investigation revealed that LRRC56 interacts with the intraflagellar transport (IFT) protein IFT88. The link with IFT was interrogated in Trypanosoma brucei. In this protist, LRRC56 is recruited to the cilium during axoneme construction, where it co-localizes with IFT trains and is required for the addition of dynein arms to the distal end of the flagellum. In T. brucei carrying LRRC56-null mutations, or a variant resulting in the p.Leu259Pro substitution corresponding to the p.Leu140Pro variant seen in one of the affected families, we observed abnormal ciliary beat patterns and an absence of outer dynein arms restricted to the distal portion of the axoneme. Together, our findings confirm that deleterious variants in LRRC56 result in a human disease and suggest that this protein has a likely role in dynein transport during cilia assembly that is evolutionarily important for cilia motility.
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Affiliation(s)
- Serge Bonnefoy
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France
| | - Christopher M Watson
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK; School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Kristin D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Moara Lemos
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France
| | - Sebastian Hutchinson
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France
| | - James A Poulter
- School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Laura A Crinnion
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK; School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Ian Berry
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Jennifer Simmonds
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Pradeep Vasudevan
- Centre for PCD Diagnosis and Research, Department of Infection, Immunity and Inflammation, RKCSB, University of Leicester, Leicester LE2 7LX, UK
| | - Chris O'Callaghan
- Centre for PCD Diagnosis and Research, Department of Infection, Immunity and Inflammation, RKCSB, University of Leicester, Leicester LE2 7LX, UK; Respiratory, Critical Care & Anaesthesia, Institute of Child Health, University College London & Great Ormond Street Children's Hospital, 30 Guilford Street, London WC1N 1EH, UK
| | - Robert A Hirst
- Centre for PCD Diagnosis and Research, Department of Infection, Immunity and Inflammation, RKCSB, University of Leicester, Leicester LE2 7LX, UK
| | - Andrew Rutman
- Centre for PCD Diagnosis and Research, Department of Infection, Immunity and Inflammation, RKCSB, University of Leicester, Leicester LE2 7LX, UK
| | - Lijia Huang
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Taila Hartley
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - David Grynspan
- Department of Pathology, Children's Hospital of Eastern Ontario, 401 Smyth Road, Ottawa, ON K1H 8L1, Canada
| | - Eduardo Moya
- Bradford Royal Infirmary, Bradford, West Yorkshire BD9 6R, UK
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Ian M Carr
- School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK
| | - David T Bonthron
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK; School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK
| | - Michel Leroux
- Department of Molecular Biology and Biochemistry, and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC, Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON K1H 8L1, Canada
| | - Philippe Bastin
- Trypanosome Cell Biology Unit & INSERM U1201, Institut Pasteur, 25, rue du Docteur Roux, 75015 Paris, France.
| | - Eamonn G Sheridan
- Yorkshire Regional Genetics Service, St. James's University Hospital, Leeds LS9 7TF, UK; School of Medicine, University of Leeds, St. James's University Hospital, Leeds LS9 7TF, UK.
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45
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Bertiaux E, Mallet A, Fort C, Blisnick T, Bonnefoy S, Jung J, Lemos M, Marco S, Vaughan S, Trépout S, Tinevez JY, Bastin P. Bidirectional intraflagellar transport is restricted to two sets of microtubule doublets in the trypanosome flagellum. J Cell Biol 2018; 217:4284-4297. [PMID: 30275108 PMCID: PMC6279389 DOI: 10.1083/jcb.201805030] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/06/2018] [Accepted: 09/21/2018] [Indexed: 12/22/2022] Open
Abstract
Intraflagellar transport (IFT) is the movement of large protein complexes responsible for the construction of cilia and flagella. Using a combination of three-dimensional electron microscopy and high-resolution live imaging, Bertiaux et al. show that IFT takes place on only four microtubule doublets out of the nine available in the trypanosome flagellum. Intraflagellar transport (IFT) is the rapid bidirectional movement of large protein complexes driven by kinesin and dynein motors along microtubule doublets of cilia and flagella. In this study, we used a combination of high-resolution electron and light microscopy to investigate how and where these IFT trains move within the flagellum of the protist Trypanosoma brucei. Focused ion beam scanning electron microscopy (FIB-SEM) analysis of trypanosomes showed that trains are found almost exclusively along two sets of doublets (3–4 and 7–8) and distribute in two categories according to their length. High-resolution live imaging of cells expressing mNeonGreen::IFT81 or GFP::IFT52 revealed for the first time IFT trafficking on two parallel lines within the flagellum. Anterograde and retrograde IFT occurs on each of these lines. At the distal end, a large individual anterograde IFT train is converted in several smaller retrograde trains in the space of 3–4 s while remaining on the same side of the axoneme.
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Affiliation(s)
- Eloïse Bertiaux
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France.,Université Pierre et Marie Curie Paris 6, Cellule Pasteur, Paris, France
| | - Adeline Mallet
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France.,Université Pierre et Marie Curie Paris 6, Cellule Pasteur, Paris, France.,UtechS Ultrastructural Bioimaging (Ultrapole), Institut Pasteur, Paris, France
| | - Cécile Fort
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France.,Université Pierre et Marie Curie Paris 6, Cellule Pasteur, Paris, France
| | - Thierry Blisnick
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France
| | - Serge Bonnefoy
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France
| | - Jamin Jung
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France
| | - Moara Lemos
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France
| | - Sergio Marco
- Université Paris Sud, Université Paris-Saclay, Centre National de la Recherche Scientifique, UMR 9187, Orsay, France.,Institut Curie, Paris Sciences et Lettres Research University, INSERM U1196, Orsay, France
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford, UK
| | - Sylvain Trépout
- Université Paris Sud, Université Paris-Saclay, Centre National de la Recherche Scientifique, UMR 9187, Orsay, France.,Institut Curie, Paris Sciences et Lettres Research University, INSERM U1196, Orsay, France
| | - Jean-Yves Tinevez
- UtechS Photonic Bioimaging (Imagopole), Institut Pasteur, Paris, France.,Image Analysis Hub, Institut Pasteur, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, Paris, France
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46
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Schneider A, Ochsenreiter T. Failure is not an option - mitochondrial genome segregation in trypanosomes. J Cell Sci 2018; 131:131/18/jcs221820. [PMID: 30224426 DOI: 10.1242/jcs.221820] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Unlike most other model eukaryotes, Trypanosoma brucei and its relatives have a single mitochondrion with a single-unit mitochondrial genome that is termed kinetoplast DNA (kDNA). Replication of the kDNA is coordinated with the cell cycle. During binary mitochondrial fission and prior to cytokinesis, the replicated kDNA has to be faithfully segregated to the daughter organelles. This process depends on the tripartite attachment complex (TAC) that physically links the kDNA across the two mitochondrial membranes with the basal body of the flagellum. Thus, the TAC couples segregation of the replicated kDNA with segregation of the basal bodies of the old and the new flagellum. In this Review, we provide an overview of the role of the TAC in kDNA inheritance in T. brucei We focus on recent advances regarding the molecular composition of the TAC, and discuss how the TAC is assembled and how its subunits are targeted to their respective TAC subdomains. Finally, we will contrast the segregation of the single-unit kDNA in trypanosomes to mitochondrial genome inheritance in yeast and mammals, both of which have numerous mitochondria that each contain multiple genomes.
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Affiliation(s)
- André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland
| | - Torsten Ochsenreiter
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Bern CH-3012, Switzerland
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47
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Hilton NA, Sladewski TE, Perry JA, Pataki Z, Sinclair-Davis AN, Muniz RS, Tran HL, Wurster JI, Seo J, de Graffenried CL. Identification of TOEFAZ1-interacting proteins reveals key regulators of Trypanosoma brucei cytokinesis. Mol Microbiol 2018; 109:306-326. [PMID: 29781112 PMCID: PMC6359937 DOI: 10.1111/mmi.13986] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2018] [Indexed: 01/07/2023]
Abstract
The protist parasite Trypanosoma brucei is an obligate extracellular pathogen that retains its highly polarized morphology during cell division and has evolved a novel cytokinetic process independent of non-muscle myosin II. The polo-like kinase homolog TbPLK is essential for transmission of cell polarity during division and for cytokinesis. We previously identified a putative TbPLK substrate named Tip of the Extending FAZ 1 (TOEFAZ1) as an essential kinetoplastid-specific component of the T. brucei cytokinetic machinery. We performed a proximity-dependent biotinylation identification (BioID) screen using TOEFAZ1 as a means to identify additional proteins that are involved in cytokinesis. Using quantitative proteomic methods, we identified nearly 500 TOEFAZ1-proximal proteins and characterized 59 in further detail. Among the candidates, we identified an essential putative phosphatase that regulates the expression level and localization of both TOEFAZ1 and TbPLK, a previously uncharacterized protein that is necessary for the assembly of a new cell posterior, and a microtubule plus-end directed orphan kinesin that is required for completing cleavage furrow ingression. The identification of these proteins provides new insight into T. brucei cytokinesis and establishes TOEFAZ1 as a key component of this essential and uniquely configured process in kinetoplastids.
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Affiliation(s)
- Nicholas A. Hilton
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Thomas E. Sladewski
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Jenna A. Perry
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Zemplen Pataki
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Amy N. Sinclair-Davis
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Richard S. Muniz
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Holly L. Tran
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Jenna I. Wurster
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912
| | - Jiwon Seo
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02912
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48
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Abstract
Trypanosoma brucei is a highly invasive pathogen capable of penetrating deeply into host tissues. To understand how flagellar motility facilitates cell penetration, we used cryo-electron tomography (cryo-ET) to visualize two genetically anucleate mutants with different flagellar motility behaviors. We found that the T. brucei cell body is highly deformable as defined by changes in cytoskeletal twist and spacing, in response to flagellar beating and environmental conditions. Based on the cryo-ET models, we proposed a mechanism of how flagellum motility is coupled to cell shape changes, which may facilitate penetration through size-limiting barriers. In the unicellular parasite Trypanosoma brucei, the causative agent of human African sleeping sickness, complex swimming behavior is driven by a flagellum laterally attached to the long and slender cell body. Using microfluidic assays, we demonstrated that T. brucei can penetrate through an orifice smaller than its maximum diameter. Efficient motility and penetration depend on active flagellar beating. To understand how active beating of the flagellum affects the cell body, we genetically engineered T. brucei to produce anucleate cytoplasts (zoids and minis) with different flagellar attachment configurations and different swimming behaviors. We used cryo-electron tomography (cryo-ET) to visualize zoids and minis vitrified in different motility states. We showed that flagellar wave patterns reflective of their motility states are coupled to cytoskeleton deformation. Based on these observations, we propose a mechanism for how flagellum beating can deform the cell body via a flexible connection between the flagellar axoneme and the cell body. This mechanism may be critical for T. brucei to disseminate in its host through size-limiting barriers.
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49
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Sunter J, Gull K. Shape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding. Open Biol 2018; 7:rsob.170165. [PMID: 28903998 PMCID: PMC5627057 DOI: 10.1098/rsob.170165] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/04/2017] [Indexed: 12/16/2022] Open
Abstract
The shape and form of protozoan parasites are inextricably linked to their pathogenicity. The evolutionary pressure associated with establishing and maintaining an infection and transmission to vector or host has shaped parasite morphology. However, there is not a 'one size fits all' morphological solution to these different pressures, and parasites exhibit a range of different morphologies, reflecting the diversity of their complex life cycles. In this review, we will focus on the shape and form of Leishmania spp., a group of very successful protozoan parasites that cause a range of diseases from self-healing cutaneous leishmaniasis to visceral leishmaniasis, which is fatal if left untreated.
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Affiliation(s)
- Jack Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 0BP, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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50
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Nachury MV. The molecular machines that traffic signaling receptors into and out of cilia. Curr Opin Cell Biol 2018; 51:124-131. [PMID: 29579578 PMCID: PMC5949257 DOI: 10.1016/j.ceb.2018.03.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
Cilia are surface-exposed organelles that dynamically concentrate signaling molecules to organize sensory, developmental and homeostatic pathways. Entry and exit of signaling receptors is germane to the processing of signals and the molecular machines for entry and exit have started to emerge. The IFT-A complex and its membrane recruitment factor Tulp3 complex promotes the entry of signaling receptors into cilia while the BBSome and its membrane recruitment factor Arl6GTP ferry activated signaling receptors out of cilia. Ciliary exit is a surprisingly complex process entailing passage through a first diffusion barrier at the transition zone, diffusion inside an intermediate compartment and crossing of a periciliary diffusion barrier. The two barriers may organize a privileged compartment where activated signaling receptors transiently reside.
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Affiliation(s)
- Maxence V Nachury
- UCSF School of Medicine, Department of Ophthalmology, United States.
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