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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Smithson L, Ihuoma Akazue P, Findlater L, Gwira TM, Vaughan S, Sunter JD. Diversity in new flagellum tip attachment in bloodstream form African trypanosomes. Mol Microbiol 2022; 118:510-525. [PMID: 36056717 PMCID: PMC9826329 DOI: 10.1111/mmi.14979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 01/11/2023]
Abstract
The closely related parasites Trypanosoma brucei, T. congolense, and T. vivax cause neglected tropical diseases collectively known as African Trypanosomiasis. A characteristic feature of bloodstream form T. brucei is the flagellum that is laterally attached to the side of the cell body. During the cell cycle, the new flagellum is formed alongside the old flagellum, with the new flagellum tip embedded within a mobile transmembrane junction called the groove. The molecular composition of the groove is currently unknown, which limits the analysis of this junction and assessment of its conservation in related trypanosomatids. Here, we identified 13 proteins that localize to the flagellar groove through a small-scale tagging screen. Functional analysis of a subset of these proteins by RNAi and gene deletion revealed three proteins, FCP4/TbKin15, FCP7, and FAZ45, that are involved in new flagellum tip attachment to the groove. Despite possessing orthologues of all 13 groove proteins, T. congolense and T. vivax did not assemble a canonical groove around the new flagellum tip according to 3D electron microscopy. This diversity in new flagellum tip attachment points to the rapid evolution of membrane-cytoskeleton structures that can occur without large changes in gene complement and likely reflects the niche specialization of each species.
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Affiliation(s)
- Laura Smithson
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
| | - Pearl Ihuoma Akazue
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied SciencesUniversity of GhanaAccraGhana,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied SciencesUniversity of GhanaAccraGhana,Department of Biochemistry, Faculty of Life SciencesUniversity of BeninBenin CityNigeria
| | - Lucy Findlater
- Sir William Dunn School of PathologyUniversity of OxfordOxfordUK
| | - Theresa Manful Gwira
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied SciencesUniversity of GhanaAccraGhana,Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied SciencesUniversity of GhanaAccraGhana
| | - 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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4
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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6
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Calvo-Álvarez E, Bonnefoy S, Salles A, Benson FE, McKean PG, Bastin P, Rotureau B. Redistribution of FLAgellar Member 8 during the trypanosome life cycle: Consequences for cell fate prediction. Cell Microbiol 2021; 23:e13347. [PMID: 33896083 PMCID: PMC8459223 DOI: 10.1111/cmi.13347] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 04/17/2021] [Accepted: 04/22/2021] [Indexed: 11/28/2022]
Abstract
The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian‐infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta‐marker of the flagellum stage and maturation state in trypanosomes.
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Affiliation(s)
- Estefanía Calvo-Álvarez
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France.,Trypanosome Transmission Group, Institut Pasteur, Paris, France
| | - Serge Bonnefoy
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France
| | - Audrey Salles
- Unit of Technology and Service Photonic BioImaging (UTechS PBI), C2RT, Institut Pasteur, Paris, France
| | - Fiona E Benson
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, UK
| | - Paul G McKean
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, UK
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France.,Trypanosome Transmission Group, Institut Pasteur, Paris, France
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7
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Vélez-Ramírez DE, Shimogawa MM, Ray SS, Lopez A, Rayatpisheh S, Langousis G, Gallagher-Jones M, Dean S, Wohlschlegel JA, Hill KL. APEX2 Proximity Proteomics Resolves Flagellum Subdomains and Identifies Flagellum Tip-Specific Proteins in Trypanosoma brucei. mSphere 2021; 6:e01090-20. [PMID: 33568455 DOI: 10.1128/mSphere.01090-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Trypanosoma brucei is the protozoan parasite responsible for sleeping sickness, a lethal vector-borne disease. T. brucei has a single flagellum (cilium) that plays critical roles in transmission and pathogenesis. An emerging concept is that the flagellum is organized into subdomains, each having specialized composition and function. The overall flagellum proteome has been well studied, but a critical knowledge gap is the protein composition of individual subdomains. We have tested whether APEX-based proximity proteomics could be used to examine the protein composition of T. brucei flagellum subdomains. As APEX-based labeling has not previously been described in T. brucei, we first fused APEX2 to the DRC1 subunit of the nexin-dynein regulatory complex, a well-characterized axonemal complex. We found that DRC1-APEX2 directs flagellum-specific biotinylation, and purification of biotinylated proteins yields a DRC1 “proximity proteome” having good overlap with published proteomes obtained from purified axonemes. Having validated the use of APEX2 in T. brucei, we next attempted to distinguish flagellar subdomains by fusing APEX2 to a flagellar membrane protein that is restricted to the flagellum tip, AC1, and another one that is excluded from the tip, FS179. Fluorescence microscopy demonstrated subdomain-specific biotinylation, and principal-component analysis showed distinct profiles between AC1-APEX2 and FS179-APEX2. Comparing these two profiles allowed us to identify an AC1 proximity proteome that is enriched for tip proteins, including proteins involved in signaling. Our results demonstrate that APEX2-based proximity proteomics is effective in T. brucei and can be used to resolve the proteome composition of flagellum subdomains that cannot themselves be readily purified. IMPORTANCE Sleeping sickness is a neglected tropical disease caused by the protozoan parasite Trypanosoma brucei. The disease disrupts the sleep-wake cycle, leading to coma and death if left untreated. T. brucei motility, transmission, and virulence depend on its flagellum (cilium), which consists of several different specialized subdomains. Given the essential and multifunctional role of the T. brucei flagellum, there is need for approaches that enable proteomic analysis of individual subdomains. Our work establishes that APEX2 proximity labeling can, indeed, be implemented in the biochemical environment of T. brucei and has allowed identification of proximity proteomes for different flagellar subdomains that cannot be purified. This capacity opens the possibility to study the composition and function of other compartments. We expect this approach may be extended to other eukaryotic pathogens and will enhance the utility of T. brucei as a model organism to study ciliopathies, heritable human diseases in which cilium function is impaired.
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Butenko A, Hammond M, Field MC, Ginger ML, Yurchenko V, Lukeš J. Reductionist Pathways for Parasitism in Euglenozoans? Expanded Datasets Provide New Insights. Trends Parasitol 2020; 37:100-116. [PMID: 33127331 DOI: 10.1016/j.pt.2020.10.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/21/2022]
Abstract
The unicellular trypanosomatids belong to the phylum Euglenozoa and all known species are obligate parasites. Distinct lineages infect plants, invertebrates, and vertebrates, including humans. Genome data for marine diplonemids, together with freshwater euglenids and free-living kinetoplastids, the closest known nonparasitic relatives to trypanosomatids, recently became available. Robust phylogenetic reconstructions across Euglenozoa are now possible and place the results of parasite-focused studies into an evolutionary context. Here we discuss recent advances in identifying the factors shaping the evolution of Euglenozoa, focusing on ancestral features generally considered parasite-specific. Remarkably, most of these predate the transition(s) to parasitism, suggesting that the presence of certain preconditions makes a significant lifestyle change more likely.
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Affiliation(s)
- Anzhelika Butenko
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
| | - Michael Hammond
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Mark C Field
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; School of Life Sciences, University of Dundee, Dundee, UK
| | - Michael L Ginger
- School of Applied Sciences, University of Huddersfield, Huddersfield, UK
| | - Vyacheslav Yurchenko
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic; Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
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Halliday C, Yanase R, Catta-Preta CMC, Moreira-Leite F, Myskova J, Pruzinova K, Volf P, Mottram JC, Sunter JD. Role for the flagellum attachment zone in Leishmania anterior cell tip morphogenesis. PLoS Pathog 2020; 16:e1008494. [PMID: 33091070 PMCID: PMC7608989 DOI: 10.1371/journal.ppat.1008494] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 11/03/2020] [Accepted: 09/23/2020] [Indexed: 11/25/2022] Open
Abstract
The shape and form of the flagellated eukaryotic parasite Leishmania is sculpted to its ecological niches and needs to be transmitted to each generation with great fidelity. The shape of the Leishmania cell is defined by the sub-pellicular microtubule array and the positioning of the nucleus, kinetoplast and the flagellum within this array. The flagellum emerges from the anterior end of the cell body through an invagination of the cell body membrane called the flagellar pocket. Within the flagellar pocket the flagellum is laterally attached to the side of the flagellar pocket by a cytoskeletal structure called the flagellum attachment zone (FAZ). During the cell cycle single copy organelles duplicate with a new flagellum assembling alongside the old flagellum. These are then segregated between the two daughter cells by cytokinesis, which initiates at the anterior cell tip. Here, we have investigated the role of the FAZ in the morphogenesis of the anterior cell tip. We have deleted the FAZ filament protein, FAZ2 and investigated its function using light and electron microscopy and infection studies. The loss of FAZ2 caused a disruption to the membrane organisation at the anterior cell tip, resulting in cells that were connected to each other by a membranous bridge structure between their flagella. Moreover, the FAZ2 null mutant was unable to develop and proliferate in sand flies and had a reduced parasite burden in mice. Our study provides a deeper understanding of membrane-cytoskeletal interactions that define the shape and form of an individual cell and the remodelling of that form during cell division. Leishmania are parasites that cause leishmaniasis in humans with symptoms ranging from mild cutaneous lesions to severe visceral disease. The life cycle of these parasites alternates between the human host and the sand fly vector, with distinct forms in both. These different forms have different cell shapes that are adapted for survival in these different environments. Leishmania parasites have an elongated cell shape with a flagellum extending from one end and this shape is due to a protein skeleton beneath the cell membrane. This skeleton is made up of different units one of which is called the flagellum attachment zone (FAZ), that connects the flagellum to the cell body. We have found that one of the proteins in the FAZ called FAZ2 is important for generating the shape of the cell at the point where the flagellum exits the cell. When we deleted FAZ2 we found that the cell membrane at the end of the cell was distorted resulting in unusual connections between the flagella of different cells. We found that the disruption to the cell shape reduces the ability of the parasite to infect mice and develop in the sand fly, which shows the importance of the parasite shape.
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Affiliation(s)
- Clare Halliday
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Ryuji Yanase
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | | | - Flavia Moreira-Leite
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Jitka Myskova
- Department of Parasitology, Charles University, Prague, Czech Republic
| | | | - 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
| | - Jack D. Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- * E-mail:
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10
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An T, Zhou Q, Hu H, Cormaty H, Li Z. FAZ27 cooperates with FLAM3 and ClpGM6 to maintain cell morphology in Trypanosoma brucei. J Cell Sci 2020; 133:jcs245258. [PMID: 32393602 PMCID: PMC7295586 DOI: 10.1242/jcs.245258] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/21/2020] [Indexed: 11/20/2022] Open
Abstract
The human parasite Trypanosoma brucei transitions from the trypomastigote form to the epimastigote form in the insect vector by repositioning its mitochondrial genome and flagellum-associated cytoskeleton. The molecular mechanisms underlying such changes in cell morphology remain elusive, but recent works demonstrated the involvement of three flagellar proteins, FLAM3, ClpGM6 and KIN-E, in this process by controlling the elongation of the flagellum attachment zone (FAZ). In this report, we identified a FAZ flagellum domain-localizing protein named FAZ27 and characterized its role in cell morphogenesis. Depletion of FAZ27 in the trypomastigote form caused major morphological changes and repositioning of the mitochondrial genome and flagellum-associated cytoskeleton, generating epimastigote-like cells. Furthermore, proximity biotinylation and co-immunoprecipitation identified FLAM3 and ClpGM6 as FAZ27-interacting proteins, and analyses of their functional interplay revealed an interdependency for assembly into the FAZ flagellum domain. Finally, we showed that assembly of FAZ27 occurred proximally, identical to the assembly pattern of other FAZ sub-domain proteins. Taken together, these results demonstrate a crucial role for the FAZ flagellum domain in controlling cell morphogenesis and suggest a coordinated assembly of all the FAZ sub-domains at the proximal end of the FAZ.
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Affiliation(s)
- Tai An
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Qing Zhou
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Huiqing Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Harshini Cormaty
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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11
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Dong X, Lim TK, Lin Q, He CY. Basal Body Protein TbSAF1 Is Required for Microtubule Quartet Anchorage to the Basal Bodies in Trypanosoma brucei. mBio 2020; 11:e00668-20. [PMID: 32518185 DOI: 10.1128/mBio.00668-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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12
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Kelly FD, Sanchez MA, Landfear SM. Touching the Surface: Diverse Roles for the Flagellar Membrane in Kinetoplastid Parasites. Microbiol Mol Biol Rev 2020; 84:e00079-19. [PMID: 32238446 DOI: 10.1128/MMBR.00079-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
While flagella have been studied extensively as motility organelles, with a focus on internal structures such as the axoneme, more recent research has illuminated the roles of the flagellar surface in a variety of biological processes. Parasitic protists of the order Kinetoplastida, which include trypanosomes and Leishmania species, provide a paradigm for probing the role of flagella in host-microbe interactions and illustrate that this interface between the flagellar surface and the host is of paramount importance. An increasing body of knowledge indicates that the flagellar membrane serves a multitude of functions at this interface: attachment of parasites to tissues within insect vectors, close interactions with intracellular organelles of vertebrate cells, transactions between flagella from different parasites, junctions between the flagella and the parasite cell body, emergence of nanotubes and exosomes from the parasite directed to either host or microbial targets, immune evasion, and sensing of the extracellular milieu. Recent whole-organelle or genome-wide studies have begun to identify protein components of the flagellar surface that must mediate these diverse host-parasite interactions. The increasing corpus of knowledge on kinetoplastid flagella will likely prove illuminating for other flagellated or ciliated pathogens as well.
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13
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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: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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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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15
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Verma A, Ghosh S, Salotra P, Singh R. Artemisinin-resistant Leishmania parasite modulates host cell defense mechanism and exhibits altered expression of unfolded protein response genes. Parasitol Res 2019; 118:2705-2713. [PMID: 31359134 DOI: 10.1007/s00436-019-06404-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 07/19/2019] [Indexed: 02/01/2023]
Abstract
Artemisinin, extracted from a medicinal herb Artemisia annua, is widely used to treat malaria and has shown potent anticancer activity. Artemisinin has been found to be effective against experimental visceral and cutaneous leishmaniasis. Despite extensive research to understand the complex mechanism of resistance to artemisinin, several questions remain unanswered. The artesunate (ART)-resistant line of Leishmania donovani was selected and cellular mechanisms associated with resistance to artemisinin were investigated. ART-resistant (AS-R) parasites showed reduced susceptibility towards ART both at promastigote and amastigote stage compared with ART sensitive (WT) parasites. WT and AS-R parasites were both more susceptible to ART at the early log phase of growth compared with late log phase. AS-R parasites were more infective to the host macrophages (p < 0.05). Evaluation of parasites' tolerance towards host microbicidal mechanisms revealed that AS-R parasites were more tolerant to complement-mediated lysis and nitrosative stress. ROS levels were modulated in presence of ART in AS-R parasites infected macrophages. Interestingly, infection of macrophages by AS-R parasites led to modulated levels of host interleukins, IL-2 and IL-10, in addition to nitric oxide. Additionally, AS-R parasites showed upregulated expression of genes of unfolded protein response pathway including methyltransferase domain-containing protein (HSP40) and flagellar attachment zone protein (prefoldin), that are reported to be associated with ART resistance in Plasmodium falciparum malaria. This study presents in vitro model of artemisinin-resistant Leishmania parasite and cellular mechanisms associated with ART resistance in Leishmania.
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Affiliation(s)
- Aditya Verma
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India
| | - Sushmita Ghosh
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India
| | - Poonam Salotra
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India
| | - Ruchi Singh
- ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi, 110029, India.
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16
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Harmer J, Towers K, Addison M, Vaughan S, Ginger ML, McKean PG. A centriolar FGR1 oncogene partner-like protein required for paraflagellar rod assembly, but not axoneme assembly in African trypanosomes. Open Biol 2019; 8:rsob.170218. [PMID: 30045883 PMCID: PMC6070722 DOI: 10.1098/rsob.170218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/21/2018] [Indexed: 01/21/2023] Open
Abstract
Proteins of the FGR1 oncogene partner (or FOP) family are found at microtubule organizing centres (MTOCs) including, in flagellate eukaryotes, the centriole or flagellar basal body from which the axoneme extends. We report conservation of FOP family proteins, TbFOPL and TbOFD1, in the evolutionarily divergent sleeping sickness parasite Trypanosoma brucei, showing (in contrast with mammalian cells, where FOP is essential for flagellum assembly) depletion of a trypanosome FOP homologue, TbFOPL, affects neither axoneme nor flagellum elongation. Instead, TbFOPL depletion causes catastrophic failure in assembly of a lineage-specific, extra-axonemal structure, the paraflagellar rod (PFR). That depletion of centriolar TbFOPL causes failure in PFR assembly is surprising because PFR nucleation commences approximately 2 µm distal from the basal body. When over-expressed with a C-terminal myc-epitope, TbFOPL was also observed at mitotic spindle poles. Little is known about bi-polar spindle assembly during closed trypanosome mitosis, but indication of a possible additional MTOC function for TbFOPL parallels MTOC localization of FOP-like protein TONNEAU1 in acentriolar plants. More generally, our functional analysis of TbFOPL emphasizes significant differences in evolutionary cell biology trajectories of FOP-family proteins. We discuss how at the molecular level FOP homologues may contribute to flagellum assembly and function in diverse flagellates.
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Affiliation(s)
- Jane Harmer
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Katie Towers
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Max Addison
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Michael L Ginger
- Department of Biological and Geographical Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, UK
| | - Paul G McKean
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
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17
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Sunter JD, Yanase R, Wang Z, Catta-Preta CMC, Moreira-Leite F, Myskova J, Pruzinova K, Volf P, Mottram JC, Gull K. 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; 116:6351-60. [PMID: 30850532 DOI: 10.1073/pnas.1812462116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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18
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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19
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Sun SY, Kaelber JT, Chen M, Dong X, Nematbakhsh Y, Shi J, Dougherty M, Lim CT, Schmid MF, Chiu W, He CY. Flagellum couples cell shape to motility in Trypanosoma brucei. Proc Natl Acad Sci U S A 2018; 115:E5916-25. [PMID: 29891682 DOI: 10.1073/pnas.1722618115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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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20
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An T, Li Z. An orphan kinesin controls trypanosome morphology transitions by targeting FLAM3 to the flagellum. PLoS Pathog 2018; 14:e1007101. [PMID: 29813136 PMCID: PMC5993322 DOI: 10.1371/journal.ppat.1007101] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 06/08/2018] [Accepted: 05/15/2018] [Indexed: 02/05/2023] Open
Abstract
Trypanosoma brucei undergoes life cycle form transitions from trypomastigotes to epimastigotes in the insect vector by re-positioning the mitochondrial genome and re-locating the flagellum and flagellum-associated cytoskeletal structures. The mechanism underlying these dramatic morphology transitions remains poorly understood. Here we report the regulatory role of the orphan kinesin KIN-E in controlling trypanosome morphology transitions. KIN-E localizes to the flagellum and is enriched at the flagellar tip, and this localization depends on the C-terminal m-calpain domain III-like domains. Depletion of KIN-E in the trypomastigote form of T. brucei causes major morphology changes and a gradual increase in the level of EP procyclin, generating epimastigote-like cells. Mechanistically, through its C-terminal importin α-like domain, KIN-E targets FLAM3, a flagellar protein involved in morphology transitions, to the flagellum to promote elongation of the flagellum attachment zone and positioning of the flagellum and flagellum-associated cytoskeletal structure, thereby maintaining trypomastigote cell morphology. Our findings suggest that morphology transitions in trypanosomes require KIN-E-mediated transport of FLAM3 to the flagellum. Trypanosoma brucei, the causative agent of sleeping sickness in humans and nagana in cattle in sub-Saharan Africa, has a complex life cycle by alternating between the tsetse fly vector and the mammalian hosts. In the gut of tsetse flies, trypanosomes undergo life cycle transitions from the trypomastigote form to the epimastigote form by re-positioning the mitochondrial genome and re-locating the flagellum and flagellum-associated cytoskeletal structures. Previous work demonstrated that elongation of the flagellum attachment zone plays an important role in controlling morphology transitions, but how it is regulated remains poorly understood. This work discovered that an orphan kinesin plays an essential role in regulating trypanosome morphology transitions. This novel kinesin localizes to the flagellum and targets FLAM3, one of the two flagellar proteins involved in morphology transitions, to the flagellum. This work suggests that trypanosome morphology transitions require kinesin-mediated transport of FLAM3 to the flagellum to promote the elongation of the flagellum attachment zone, thereby maintaining flagellum-cell body attachment and positioning the flagellum and flagellum-associated cytoskeletal structures to assume trypomastigote cell morphology.
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Affiliation(s)
- Tai An
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States of America
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, United States of America
- * E-mail:
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21
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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: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Harmer J, Qi X, Toniolo G, Patel A, Shaw H, Benson FE, Ginger ML, McKean PG. Variation in Basal Body Localisation and Targeting of Trypanosome RP2 and FOR20 Proteins. Protist 2017; 168:452-466. [PMID: 28822909 DOI: 10.1016/j.protis.2017.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 06/28/2017] [Accepted: 07/01/2017] [Indexed: 12/22/2022]
Abstract
TOF-LisH-PLL motifs define FOP family proteins; some members are involved in flagellum assembly. The critical role of FOP family protein FOR20 is poorly understood. Here, we report relative localisations of the four FOP family proteins in parasitic Trypanosoma brucei: TbRP2, TbOFD1 and TbFOP/FOP1-like are mature basal body proteins whereas TbFOR20 is present on pro- and mature basal bodies - on the latter it localises distal to TbRP2. We discuss how the data, together with published work for another protist Giardia intestinalis, informs on likely FOR20 function. Moreover, our localisation study provides convincing evidence that the antigen recognised by monoclonal antibody YL1/2 at trypanosome mature basal bodies is FOP family protein TbRP2, not tyrosinated α-tubulin as widely stated in the literature. Curiously, FOR20 proteins from T. brucei and closely related African trypanosomes possess short, negatively-charged N-terminal extensions absent from FOR20 in other trypanosomatids and other eukaryotes. The extension is necessary for protein targeting, but insufficient to re-direct TbRP2 to probasal bodies. Yet, FOR20 from the American trypanosome T. cruzi, which lacks any extension, localises to pro- and mature basal bodies when expressed in T. brucei. This identifies unexpected variation in FOR20 architecture that is presently unique to one clade of trypanosomatids.
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Affiliation(s)
- Jane Harmer
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Xin Qi
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Gabriella Toniolo
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Aysha Patel
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Hannah Shaw
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Fiona E Benson
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK
| | - Michael L Ginger
- Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DH, UK.
| | - Paul G McKean
- Faculty of Health and Medicine, Division of Biomedical and Life Sciences, Lancaster University, Lancaster LA1 4YQ, UK.
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23
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Peña-Diaz P, Vancová M, Resl C, Field MC, Lukeš J. A leucine aminopeptidase is involved in kinetoplast DNA segregation in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006310. [PMID: 28388690 PMCID: PMC5397073 DOI: 10.1371/journal.ppat.1006310] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 04/19/2017] [Accepted: 03/23/2017] [Indexed: 12/29/2022] Open
Abstract
The kinetoplast (k), the uniquely packaged mitochondrial DNA of trypanosomatid protists is formed by a catenated network of minicircles and maxicircles that divide and segregate once each cell cycle. Although many proteins involved in kDNA replication and segregation are now known, several key steps in the replication mechanism remain uncharacterized at the molecular level, one of which is the nabelschnur or umbilicus, a prominent structure which in the mammalian parasite Trypanosoma brucei connects the daughter kDNA networks prior to their segregation. Here we characterize an M17 family leucyl aminopeptidase metalloprotease, termed TbLAP1, which specifically localizes to the kDNA disk and the nabelschur and represents the first described protein found in this structure. We show that TbLAP1 is required for correct segregation of kDNA, with knockdown resulting in delayed cytokinesis and ectopic expression leading to kDNA loss and decreased cell proliferation. We propose that TbLAP1 is required for efficient kDNA division and specifically participates in the separation of daughter kDNA networks.
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Affiliation(s)
- Priscila Peña-Diaz
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Marie Vancová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Christian Resl
- Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Mark C. Field
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
- Canadian Institute for Advanced Research, Toronto, ON, Canada
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Moreira BP, Fonseca CK, Hammarton TC, Baqui MMA. Giant FAZ10 is required for flagellum attachment zone stabilization and furrow positioning in Trypanosoma brucei. J Cell Sci 2017; 130:1179-1193. [PMID: 28193733 PMCID: PMC5358337 DOI: 10.1242/jcs.194308] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 02/02/2017] [Indexed: 01/09/2023] Open
Abstract
The flagellum and flagellum attachment zone (FAZ) are important cytoskeletal structures in trypanosomatids, being required for motility, cell division and cell morphogenesis. Trypanosomatid cytoskeletons contain abundant high molecular mass proteins (HMMPs), but many of their biological functions are still unclear. Here, we report the characterization of the giant FAZ protein, FAZ10, in Trypanosoma brucei, which, using immunoelectron microscopy, we show localizes to the intermembrane staples in the FAZ intracellular domain. Our data show that FAZ10 is a giant cytoskeletal protein essential for normal growth and morphology in both procyclic and bloodstream parasite life cycle stages, with its depletion leading to defects in cell morphogenesis, flagellum attachment, and kinetoplast and nucleus positioning. We show that the flagellum attachment defects are probably brought about by reduced tethering of the proximal domain of the paraflagellar rod to the FAZ filament. Further, FAZ10 depletion also reduces abundance of FAZ flagellum domain protein, ClpGM6. Moreover, ablation of FAZ10 impaired the timing and placement of the cleavage furrow during cytokinesis, resulting in premature or asymmetrical cell division.
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Affiliation(s)
- Bernardo P Moreira
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil
| | - Carol K Fonseca
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil
| | - Tansy C Hammarton
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Munira M A Baqui
- Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil
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25
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Horáková E, Changmai P, Vancová M, Sobotka R, Van Den Abbeele J, Vanhollebeke B, Lukeš J. The Trypanosoma brucei TbHrg protein is a heme transporter involved in the regulation of stage-specific morphological transitions. J Biol Chem 2017; 292:6998-7010. [PMID: 28232490 DOI: 10.1074/jbc.m116.762997] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 02/21/2017] [Indexed: 12/27/2022] Open
Abstract
The human parasite Trypanosoma brucei does not synthesize heme de novo and instead relies entirely on heme supplied by its vertebrate host or its insect vector, the tsetse fly. In the host bloodstream T. brucei scavenges heme via haptoglobin-hemoglobin (HpHb) receptor-mediated endocytosis occurring in the flagellar pocket. However, in the procyclic developmental stage, in which T. brucei is confined to the tsetse fly midgut, this receptor is apparently not expressed, suggesting that T. brucei takes up heme by a different, unknown route. To define this alternative route, we functionally characterized heme transporter TbHrg in the procyclic stage. RNAi-induced down-regulation of TbHrg in heme-limited culture conditions resulted in slower proliferation, decreased cellular heme, and marked changes in cellular morphology so that the cells resemble mesocyclic trypomastigotes. Nevertheless, the TbHrg KO developed normally in the tsetse flies at rates comparable with wild-type cells. T. brucei cells overexpressing TbHrg displayed up-regulation of the early procyclin GPEET and down-regulation of the late procyclin EP1, two proteins coating the T. brucei surface in the procyclic stage. Light microscopy of immunostained TbHrg indicated localization to the flagellar membrane, and scanning electron microscopy revealed more intense TbHrg accumulation toward the flagellar pocket. Based on these findings, we postulate that T. brucei senses heme levels via the flagellar TbHrg protein. Heme deprivation in the tsetse fly anterior midgut might represent an environmental stimulus involved in the transformation of this important human parasite, possibly through metabolic remodeling.
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Affiliation(s)
- Eva Horáková
- From the Institute of Parasitology, Biology Center, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
| | - Piya Changmai
- From the Institute of Parasitology, Biology Center, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic
| | - Marie Vancová
- From the Institute of Parasitology, Biology Center, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic.,Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Roman Sobotka
- Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic.,Institute of Microbiology, Czech Academy of Sciences, 37981 Třeboň, Czech Republic
| | - Jan Van Den Abbeele
- Department of Biomedical Sciences, Unit of Veterinary Protozoology, Institute of Tropical Medicine, B2000 Antwerp, Belgium
| | - Benoit Vanhollebeke
- Institut de Biologie et de Médecine Moléculaires, Université Libre de Bruxelles, B6041 Gosselies, Belgium, and
| | - Julius Lukeš
- From the Institute of Parasitology, Biology Center, Czech Academy of Sciences, 37005 České Budějovice (Budweis), Czech Republic, .,Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic.,Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada
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26
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Sanchez MA, Tran KD, Valli J, Hobbs S, Johnson E, Gluenz E, Landfear SM. KHARON Is an Essential Cytoskeletal Protein Involved in the Trafficking of Flagellar Membrane Proteins and Cell Division in African Trypanosomes. J Biol Chem 2016; 291:19760-73. [PMID: 27489106 DOI: 10.1074/jbc.m116.739235] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Indexed: 11/06/2022] Open
Abstract
African trypanosomes and related kinetoplastid parasites selectively traffic specific membrane proteins to the flagellar membrane, but the mechanisms for this trafficking are poorly understood. We show here that KHARON, a protein originally identified in Leishmania parasites, interacts with a putative trypanosome calcium channel and is required for its targeting to the flagellar membrane. KHARON is located at the base of the flagellar axoneme, where it likely mediates targeting of flagellar membrane proteins, but is also on the subpellicular microtubules and the mitotic spindle. Hence, KHARON is probably a multifunctional protein that associates with several components of the trypanosome cytoskeleton. RNA interference-mediated knockdown of KHARON mRNA results in failure of the calcium channel to enter the flagellar membrane, detachment of the flagellum from the cell body, and disruption of mitotic spindles. Furthermore, knockdown of KHARON mRNA induces a lethal failure of cytokinesis in both bloodstream (mammalian host) and procyclic (insect vector) life cycle stages, and KHARON is thus critical for parasite viability.
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Affiliation(s)
- Marco A Sanchez
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Khoa D Tran
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Jessica Valli
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Sam Hobbs
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
| | - Errin Johnson
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Eva Gluenz
- the Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Scott M Landfear
- From the Department of Molecular Microbiology & Immunology, Oregon Health & Science University, Portland, Oregon 97239 and
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27
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Perdomo D, Bonhivers M, Robinson DR. The Trypanosome Flagellar Pocket Collar and Its Ring Forming Protein-TbBILBO1. Cells 2016; 5:cells5010009. [PMID: 26950156 PMCID: PMC4810094 DOI: 10.3390/cells5010009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 12/11/2022] Open
Abstract
Sub-species of Trypanosoma brucei are the causal agents of human African sleeping sickness and Nagana in domesticated livestock. These pathogens have developed an organelle-like compartment called the flagellar pocket (FP). The FP carries out endo- and exocytosis and is the only structure this parasite has evolved to do so. The FP is essential for parasite viability, making it an interesting structure to evaluate as a drug target, especially since it has an indispensible cytoskeleton component called the flagellar pocket collar (FPC). The FPC is located at the neck of the FP where the flagellum exits the cell. The FPC has a complex architecture and division cycle, but little is known concerning its organization. Recent work has focused on understanding how the FP and the FPC are formed and as a result of these studies an important calcium-binding, polymer-forming protein named TbBILBO1 was identified. Cellular biology analysis of TbBILBO1 has demonstrated its uniqueness as a FPC component and until recently, it was unknown what structural role it played in forming the FPC. This review summarizes the recent data on the polymer forming properties of TbBILBO1 and how these are correlated to the FP cytoskeleton.
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Affiliation(s)
- Doranda Perdomo
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
| | - Mélanie Bonhivers
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
| | - Derrick R Robinson
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
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28
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Sunter JD, Gull K. The Flagellum Attachment Zone: 'The Cellular Ruler' of Trypanosome Morphology. Trends Parasitol 2016; 32:309-324. [PMID: 26776656 PMCID: PMC4827413 DOI: 10.1016/j.pt.2015.12.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/27/2015] [Accepted: 12/15/2015] [Indexed: 12/17/2022]
Abstract
A defining feature of Trypanosoma brucei cell shape is the lateral attachment of the flagellum to the cell body, mediated by the flagellum attachment zone (FAZ). The FAZ is a complex cytoskeletal structure that connects the flagellum skeleton through two membranes to the cytoskeleton. The FAZ acts as a ‘cellular ruler’ of morphology by regulating cell length and organelle position and is therefore critical for both cell division and life cycle differentiations. Here we provide an overview of the advances in our understanding of the composition, assembly, and function of the FAZ. The flagellum attachment zone (FAZ) is a large cytoskeletal structure that connects the flagellum skeleton to the cell body cytoskeleton through the membrane of both the flagellum and the cell body. The structure can be divided into eight zones. The FAZ is a key morphogenetic structure regulating both cell length and organelle positioning. Recent studies have identified numerous FAZ proteins. The function of a subset of these proteins has been studied by RNAi, revealing a range of different phenotypes from flagellum detachment to organelle positioning effects. The assembly of the FAZ occurs at its proximal end – the opposite polarity to that of the flagellar axoneme and paraflagellar rod.
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Affiliation(s)
- Jack D Sunter
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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29
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Wilson CS, Chang AJ, Greene R, Machado S, Parsons MW, Takats TA, Zambetti LJ, Springer AL. Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment. PLoS One 2015; 10:e0139579. [PMID: 26555902 PMCID: PMC4640498 DOI: 10.1371/journal.pone.0139579] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 09/15/2015] [Indexed: 12/23/2022] Open
Abstract
Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.
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Affiliation(s)
- Corinne S. Wilson
- Department of Biology, Siena College, Loudonville, New York, United States of America
| | - Alex J. Chang
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Rebecca Greene
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Sulynn Machado
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Matthew W. Parsons
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Taylor A. Takats
- Department of Biology, Siena College, Loudonville, New York, United States of America
| | - Luke J. Zambetti
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Amy L. Springer
- Department of Biology, Siena College, Loudonville, New York, United States of America
- * E-mail:
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30
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Hu H, Zhou Q, Li Z. SAS-4 Protein in Trypanosoma brucei Controls Life Cycle Transitions by Modulating the Length of the Flagellum Attachment Zone Filament. J Biol Chem 2015; 290:30453-63. [PMID: 26504079 DOI: 10.1074/jbc.m115.694109] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Indexed: 01/05/2023] Open
Abstract
The evolutionarily conserved centriole/basal body protein SAS-4 regulates centriole duplication in metazoa and basal body duplication in flagellated and ciliated organisms. Here, we report that the SAS-4 homolog in the flagellated protozoan Trypanosoma brucei, TbSAS-4, plays an unusual role in controlling life cycle transitions by regulating the length of the flagellum attachment zone (FAZ) filament, a specialized cytoskeletal structure required for flagellum adhesion and cell morphogenesis. TbSAS-4 is concentrated at the distal tip of the FAZ filament, and depletion of TbSAS-4 in the trypomastigote form disrupts the elongation of the new FAZ filament, generating cells with a shorter FAZ associated with a longer unattached flagellum and repositioned kinetoplast and basal body, reminiscent of epimastigote-like morphology. Further, we show that TbSAS-4 associates with six additional FAZ tip proteins, and depletion of TbSAS-4 disrupts the enrichment of these FAZ tip proteins at the new FAZ tip, suggesting a role of TbSAS-4 in maintaining the integrity of this FAZ tip protein complex. Together, these results uncover a novel function of TbSAS-4 in regulating the length of the FAZ filament to control basal body positioning and life cycle transitions in T. brucei.
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Affiliation(s)
- Huiqing Hu
- From the Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas 77030
| | - Qing Zhou
- From the Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas 77030
| | - Ziyin Li
- From the Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas 77030
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