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Ahmed M, Wheeler R, Týč J, Shafiq S, Sunter J, Vaughan S. Identification of 30 transition fibre proteins in Trypanosoma brucei reveals a complex and dynamic structure. J Cell Sci 2024; 137:jcs261692. [PMID: 38572631 PMCID: PMC11190437 DOI: 10.1242/jcs.261692] [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: 09/29/2023] [Accepted: 03/26/2024] [Indexed: 04/05/2024] Open
Abstract
Transition fibres and distal appendages surround the distal end of mature basal bodies and are essential for ciliogenesis, but only a few of the proteins involved have been identified and functionally characterised. Here, through genome-wide analysis, we have identified 30 transition fibre proteins (TFPs) and mapped their arrangement in the flagellated eukaryote Trypanosoma brucei. We discovered that TFPs are recruited to the mature basal body before and after basal body duplication, with differential expression of five TFPs observed at the assembling new flagellum compared to the existing fixed-length old flagellum. RNAi-mediated depletion of 17 TFPs revealed six TFPs that are necessary for ciliogenesis and a further three TFPs that are necessary for normal flagellum length. We identified nine TFPs that had a detectable orthologue in at least one basal body-forming eukaryotic organism outside of the kinetoplastid parasites. Our work has tripled the number of known transition fibre components, demonstrating that transition fibres are complex and dynamic in their composition throughout the cell cycle, which relates to their essential roles in ciliogenesis and flagellum length regulation.
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Affiliation(s)
- Manu Ahmed
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Richard Wheeler
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford OX1 3SY, UK
| | - Jiří Týč
- Biology Centre CAS, Institute of Parasitology, Branišovská 1160/31, 370 05 České Budějovice, Czech Republic
| | - Shahaan Shafiq
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Jack Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
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Vinay L, Belleannée C. EV duty vehicles: Features and functions of ciliary extracellular vesicles. Front Genet 2022; 13:916233. [PMID: 36061180 PMCID: PMC9438925 DOI: 10.3389/fgene.2022.916233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/08/2022] [Indexed: 12/12/2022] Open
Abstract
The primary cilium is a microtubule-based organelle that extends from a basal body at the surface of most cells. This antenna is an efficient sensor of the cell micro-environment and is instrumental to the proper development and homeostatic control of organs. Recent compelling studies indicate that, in addition to its role as a sensor, the primary cilium also emits signals through the release of bioactive extracellular vesicles (EVs). While some primary-cilium derived EVs are released through an actin-dependent ectocytosis and are called ectosomes (or large EVs, 350–500 nm), others originate from the exocytosis of multivesicular bodies and are smaller (small EVs, 50–100 nm). Ciliary EVs carry unique signaling factors, including protein markers and microRNAs (miRNAs), and participate in intercellular communication in different organism models. This review discusses the mechanism of release, the molecular features, and functions of EVs deriving from cilia, based on the existing literature.
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Atkins M, Týč J, Shafiq S, Ahmed M, Bertiaux E, De Castro Neto AL, Sunter J, Bastin P, Dean SD, Vaughan S. CEP164C regulates flagellum length in stable flagella. J Cell Biol 2021; 220:211523. [PMID: 33165561 PMCID: PMC7833213 DOI: 10.1083/jcb.202001160] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 08/11/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022] Open
Abstract
Cilia and flagella are required for cell motility and sensing the external environment and can vary in both length and stability. Stable flagella maintain their length without shortening and lengthening and are proposed to “lock” at the end of growth, but molecular mechanisms for this lock are unknown. We show that CEP164C contributes to the locking mechanism at the base of the flagellum in Trypanosoma brucei. CEP164C localizes to mature basal bodies of fully assembled old flagella, but not to growing new flagella, and basal bodies only acquire CEP164C in the third cell cycle after initial assembly. Depletion of CEP164C leads to dysregulation of flagellum growth, with continued growth of the old flagellum, consistent with defects in a flagellum locking mechanism. Inhibiting cytokinesis results in CEP164C acquisition on the new flagellum once it reaches the old flagellum length. These results provide the first insight into the molecular mechanisms regulating flagella growth in cells that must maintain existing flagella while growing new flagella.
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Affiliation(s)
- Madison Atkins
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Jiří Týč
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Shahaan Shafiq
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Manu Ahmed
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Eloïse Bertiaux
- Trypanosome Cell Biology Unit and Institut National de la Santé et de la Recherche Médicale U1201, Institut Pasteur, Paris, France.,Sorbonne Université école doctorale complexité du vivant, Paris, France
| | | | - Jack Sunter
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
| | - Philippe Bastin
- Trypanosome Cell Biology Unit and Institut National de la Santé et de la Recherche Médicale U1201, Institut Pasteur, Paris, France
| | | | - Sue Vaughan
- Biological and Medical Sciences, Oxford Brookes University, Oxford, UK
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Angelici MC, Walochnik J, Calderaro A, Saxinger L, Dacks JB. Free-living amoebae and other neglected protistan pathogens: Health emergency signals? Eur J Protistol 2020; 77:125760. [PMID: 33340850 DOI: 10.1016/j.ejop.2020.125760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 10/25/2020] [Accepted: 11/13/2020] [Indexed: 02/08/2023]
Abstract
Protistan parasites have an undisputed global health impact. However, outside of a few key exceptions, e.g. the agent of malaria, most of these infectious agents are neglected as important health threats. The Symposium entitled "Free-living amoebae and neglected pathogenic protozoa: health emergency signals?" held at the European Congress of Protistology in Rome, July 2019, brought together researchers addressing scientific and clinical questions about some of these fascinating organisms. Topics presented included the molecular basis of pathogenicity in Acanthamoeba; genomics of Naegleria fowleri; and epidemiology of poorly diagnosed enteric protistan species, including Giardia, Cryptosporidium, Blastocystis, Dientamoeba. The Symposium aim was to excite the audience about the opportunities and challenges of research in these underexplored organisms and to underline the public health implications of currently under-appreciated protistan infections. The major take home message is that any knowledge that we gain about these organisms will allow us to better address them, in terms of monitoring and treatment, as sources of future health emergencies.
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Affiliation(s)
| | - Julia Walochnik
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Adriana Calderaro
- Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Lynora Saxinger
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, University of Alberta, Alberta, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences České Budějovice, Czech Republic.
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Bertiaux E, Mallet A, Rotureau B, Bastin P. Intraflagellar transport during assembly of flagella of different length in Trypanosoma brucei isolated from tsetse flies. J Cell Sci 2020; 133:jcs248989. [PMID: 32843573 DOI: 10.1242/jcs.248989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 08/10/2020] [Indexed: 11/20/2022] Open
Abstract
Multicellular organisms assemble cilia and flagella of precise lengths differing from one cell to another, yet little is known about the mechanisms governing these differences. Similarly, protists assemble flagella of different lengths according to the stage of their life cycle. Trypanosoma brucei assembles flagella of 3 to 30 µm during its development in the tsetse fly. This provides an opportunity to examine how cells naturally modulate organelle length. Flagella are constructed by addition of new blocks at their distal end via intraflagellar transport (IFT). Immunofluorescence assays, 3D electron microscopy and live-cell imaging revealed that IFT was present in all T. brucei life cycle stages. IFT proteins are concentrated at the base, and IFT trains are located along doublets 3-4 and 7-8 and travel bidirectionally in the flagellum. Quantitative analysis demonstrated that the total amount of flagellar IFT proteins correlates with the length of the flagellum. Surprisingly, the shortest flagellum exhibited a supplementary large amount of dynamic IFT material at its distal end. The contribution of IFT and other factors to the regulation of flagellum length is discussed.
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Affiliation(s)
- Eloïse Bertiaux
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 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
| | - Adeline Mallet
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 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
- Ultrastructural Bio Imaging Unit, C2RT, Institut Pasteur, 25 Rue du Docteur Roux, 75015 Paris, France
| | - Brice Rotureau
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015 Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015 Paris, France
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Petriman NA, Lorentzen E. Structural insights into the architecture and assembly of eukaryotic flagella. MICROBIAL CELL (GRAZ, AUSTRIA) 2020; 7:289-299. [PMID: 33150161 PMCID: PMC7590530 DOI: 10.15698/mic2020.11.734] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/16/2022]
Abstract
Cilia and flagella are slender projections found on most eukaryotic cells including unicellular organisms such as Chlamydomonas, Trypanosoma and Tetrahymena, where they serve motility and signaling functions. The cilium is a large molecular machine consisting of hundreds of different proteins that are trafficked into the organelle to organize a repetitive microtubule-based axoneme. Several recent studies took advantage of improved cryo-EM methodology to unravel the high-resolution structures of ciliary complexes. These include the recently reported purification and structure determination of axonemal doublet microtubules from the green algae Chlamydomonas reinhardtii, which allows for the modeling of more than 30 associated protein factors to provide deep molecular insight into the architecture and repetitive nature of doublet microtubules. In addition, we will review several recent contributions that dissect the structure and function of ciliary trafficking complexes that ferry structural and signaling components between the cell body and the cilium organelle.
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Affiliation(s)
- Narcis-Adrian Petriman
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
| | - Esben Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10c, DK-8000 Aarhus C, Denmark
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Teves ME, Roldan ERS, Krapf D, Strauss III JF, Bhagat V, Sapao P. Sperm Differentiation: The Role of Trafficking of Proteins. Int J Mol Sci 2020; 21:E3702. [PMID: 32456358 PMCID: PMC7279445 DOI: 10.3390/ijms21103702] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/10/2020] [Accepted: 05/20/2020] [Indexed: 12/15/2022] Open
Abstract
Sperm differentiation encompasses a complex sequence of morphological changes that takes place in the seminiferous epithelium. In this process, haploid round spermatids undergo substantial structural and functional alterations, resulting in highly polarized sperm. Hallmark changes during the differentiation process include the formation of new organelles, chromatin condensation and nuclear shaping, elimination of residual cytoplasm, and assembly of the sperm flagella. To achieve these transformations, spermatids have unique mechanisms for protein trafficking that operate in a coordinated fashion. Microtubules and filaments of actin are the main tracks used to facilitate the transport mechanisms, assisted by motor and non-motor proteins, for delivery of vesicular and non-vesicular cargos to specific sites. This review integrates recent findings regarding the role of protein trafficking in sperm differentiation. Although a complete characterization of the interactome of proteins involved in these temporal and spatial processes is not yet known, we propose a model based on the current literature as a framework for future investigations.
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Affiliation(s)
- Maria E. Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Eduardo R. S. Roldan
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales (CSIC), 28006-Madrid, Spain
| | - Diego Krapf
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA;
| | - Jerome F. Strauss III
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Virali Bhagat
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond VA 23298, USA;
| | - Paulene Sapao
- Department of Chemistry, Virginia Commonwealth University, Richmond VA, 23298, USA;
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