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Hair M, Yanase R, Moreira-Leite F, Wheeler RJ, Sádlová J, Volf P, Vaughan S, Sunter JD. Whole cell reconstructions of Leishmania mexicana through the cell cycle. PLoS Pathog 2024; 20:e1012054. [PMID: 38416776 PMCID: PMC10927142 DOI: 10.1371/journal.ppat.1012054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/11/2024] [Accepted: 02/15/2024] [Indexed: 03/01/2024] Open
Abstract
The unicellular parasite Leishmania has a precisely defined cell architecture that is inherited by each subsequent generation, requiring a highly coordinated pattern of duplication and segregation of organelles and cytoskeletal structures. A framework of nuclear division and morphological changes is known from light microscopy, yet this has limited resolution and the intrinsic organisation of organelles within the cell body and their manner of duplication and inheritance is unknown. Using volume electron microscopy approaches, we have produced three-dimensional reconstructions of different promastigote cell cycle stages to give a spatial and quantitative overview of organelle positioning, division and inheritance. The first morphological indications seen in our dataset that a new cell cycle had begun were the assembly of a new flagellum, the duplication of the contractile vacuole and the increase in volume of the nucleus and kinetoplast. We showed that the progression of the cytokinesis furrow created a specific pattern of membrane indentations, while our analysis of sub-pellicular microtubule organisation indicated that there is likely a preferred site of new microtubule insertion. The daughter cells retained these indentations in their cell body for a period post-abscission. By comparing cultured and sand fly derived promastigotes, we found an increase in the number and overall volume of lipid droplets in the promastigotes from the sand fly, reflecting a change in their metabolism to ensure transmissibility to the mammalian host. Our insights into the cell cycle mechanics of Leishmania will support future molecular cell biology analyses of these parasites.
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Affiliation(s)
- Molly Hair
- 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
| | - Flávia Moreira-Leite
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Richard John Wheeler
- Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, United Kingdom
| | - Jovana Sádlová
- Department of Parasitology, Charles University, Prague, Czech Republic
| | - Petr Volf
- Department of Parasitology, Charles University, Prague, Czech Republic
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
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2
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Povelones ML, Holmes NA, Povelones M. A sticky situation: When trypanosomatids attach to insect tissues. PLoS Pathog 2023; 19:e1011854. [PMID: 38128049 PMCID: PMC10734937 DOI: 10.1371/journal.ppat.1011854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023] Open
Abstract
Transmission of trypanosomatids to their mammalian hosts requires a complex series of developmental transitions in their insect vectors, including stable attachment to an insect tissue. While there are many ultrastructural descriptions of attached cells, we know little about the signaling events and molecular mechanisms involved in this process. Each trypanosomatid species attaches to a specific tissue in the insect at a particular stage of its life cycle. Attachment is mediated by the flagellum, which is modified to accommodate a filament-rich plaque within an expanded region of the flagellar membrane. Attachment immediately precedes differentiation to the mammal-infectious stage and in some cases a direct mechanistic link has been demonstrated. In this review, we summarize the current state of knowledge of trypanosomatid attachment in insects, including structure, function, signaling, candidate molecules, and changes in gene expression. We also highlight remaining questions about this process and how the field is poised to address them through modern approaches.
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Affiliation(s)
- Megan L. Povelones
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Nikki A. Holmes
- Department of Biology, Villanova University, Villanova, Pennsylvania, United States of America
| | - Michael Povelones
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
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3
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Souza Onofre T, Pham KTM, Zhou Q, Li Z. The microtubule quartet protein SNAP1 in Trypanosoma brucei facilitates flagellum and cell division plane positioning by promoting basal body segregation. J Biol Chem 2023; 299:105340. [PMID: 37838178 PMCID: PMC10656233 DOI: 10.1016/j.jbc.2023.105340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/21/2023] [Accepted: 10/07/2023] [Indexed: 10/16/2023] Open
Abstract
The unicellular protozoan Trypanosoma brucei has a single flagellum that is involved in cell motility, cell morphogenesis, and cell division. Inheritance of the newly assembled flagellum during the cell cycle requires its correct positioning, which depends on the faithful duplication or segregation of multiple flagellum-associated cytoskeletal structures, including the basal body, the flagellum attachment zone, and the hook complex. Along the flagellum attachment zone sites a set of four microtubules termed the microtubule quartet (MtQ), whose molecular function remains enigmatic. We recently reported that the MtQ-localized protein NHL1 interacts with the microtubule-binding protein TbSpef1 and regulates flagellum inheritance by promoting basal body rotation and segregation. Here, we identified a TbSpef1- and NHL1-associated protein named SNAP1, which co-localizes with NHL1 and TbSpef1 at the proximal portion of the MtQ, depends on TbSpef1 for localization and is required for NHL1 localization to the MtQ. Knockdown of SNAP1 impairs the rotation and segregation of the basal body, the elongation of the flagellum attachment zone filament, and the positioning of the newly assembled flagellum, thereby causing mis-placement of the cell division plane, a halt in cleavage furrow ingression, and an inhibition of cytokinesis completion. Together, these findings uncover a coordinating role of SNAP1 with TbSpef1 and NHL1 in facilitating flagellum positioning and cell division plane placement for the completion of cytokinesis.
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Affiliation(s)
- Thiago Souza Onofre
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Kieu T M Pham
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Qing Zhou
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA.
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4
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Albisetti AC, Douglas RL, Welch MD. FAZ assembly in bloodstream form Trypanosoma brucei requires kinesin KIN-E. Mol Biol Cell 2023; 34:ar103. [PMID: 37531263 PMCID: PMC10551704 DOI: 10.1091/mbc.e23-01-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 08/04/2023] Open
Abstract
Trypanosoma brucei, the causative agent of African sleeping sickness, uses its flagellum for movement, cell division, and signaling. The flagellum is anchored to the cell body membrane via the flagellum attachment zone (FAZ), a complex of proteins, filaments, and microtubules that spans two membranes with elements on both flagellum and cell body sides. How FAZ components are carried into place to form this complex is poorly understood. Here, we show that the trypanosome-specific kinesin KIN-E is required for building the FAZ in bloodstream-form parasites. KIN-E is localized along the flagellum with a concentration at its distal tip. Depletion of KIN-E by RNAi rapidly inhibits flagellum attachment and leads to cell death. A detailed analysis reveals that KIN-E depletion phenotypes include failure in cytokinesis completion, kinetoplast DNA missegregation, and transport vesicle accumulation. Together with previously published results in procyclic form parasites, these data suggest KIN-E plays a critical role in FAZ assembly in T. brucei.
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Affiliation(s)
- Anna C. Albisetti
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Robert L. Douglas
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Matthew D. Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
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5
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Morales J, Ehret G, Poschmann G, Reinicke T, Maurya AK, Kröninger L, Zanini D, Wolters R, Kalyanaraman D, Krakovka M, Bäumers M, Stühler K, Nowack ECM. Host-symbiont interactions in Angomonas deanei include the evolution of a host-derived dynamin ring around the endosymbiont division site. Curr Biol 2023; 33:28-40.e7. [PMID: 36480982 DOI: 10.1016/j.cub.2022.11.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/09/2022] [Accepted: 11/09/2022] [Indexed: 12/12/2022]
Abstract
The trypanosomatid Angomonas deanei is a model to study endosymbiosis. Each cell contains a single β-proteobacterial endosymbiont that divides at a defined point in the host cell cycle and contributes essential metabolites to the host metabolism. Additionally, one endosymbiont gene, encoding an ornithine cyclodeaminase (OCD), was transferred by endosymbiotic gene transfer (EGT) to the nucleus. However, the molecular mechanisms mediating the intricate host/symbiont interactions are largely unexplored. Here, we used protein mass spectrometry to identify nucleus-encoded proteins that co-purify with the endosymbiont. Expression of fluorescent fusion constructs of these proteins in A. deanei confirmed seven host proteins to be recruited to specific sites within the endosymbiont. These endosymbiont-targeted proteins (ETPs) include two proteins annotated as dynamin-like protein and peptidoglycan hydrolase that form a ring-shaped structure around the endosymbiont division site that remarkably resembles organellar division machineries. The EGT-derived OCD was not among the ETPs, but instead localizes to the glycosome, likely enabling proline production in the glycosome. We hypothesize that recalibration of the metabolic capacity of the glycosomes that are closely associated with the endosymbiont helps to supply the endosymbiont with metabolites it is auxotrophic for and thus supports the integration of host and endosymbiont metabolic networks. Hence, scrutiny of endosymbiosis-induced protein re-localization patterns in A. deanei yielded profound insights into how an endosymbiotic relationship can stabilize and deepen over time far beyond the level of metabolite exchange.
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Affiliation(s)
- Jorge Morales
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Georg Ehret
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Gereon Poschmann
- Institute of Molecular Medicine, Proteome Research, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Tobias Reinicke
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Anay K Maurya
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Lena Kröninger
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Davide Zanini
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Rebecca Wolters
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Dhevi Kalyanaraman
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Michael Krakovka
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Miriam Bäumers
- Center for Advanced Imaging, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany
| | - Kai Stühler
- Institute of Molecular Medicine, Proteome Research, Medical Faculty and University Hospital, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany; Molecular Proteomics Laboratory, Biological and Medical Research Centre (BMFZ), Heinrich Heine University Düsseldorf, Universitätsstr 1, 40225 Düsseldorf, Germany
| | - Eva C M Nowack
- Institute of Microbial Cell Biology, Department of Biology, Heinrich Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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6
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Benz C, Müller N, Kaltenbrunner S, Váchová H, Vancová M, Lukeš J, Varga V, Hashimi H. Kinetoplastid-specific X2-family kinesins interact with a kinesin-like pleckstrin homology domain protein that localizes to the trypanosomal microtubule quartet. Mol Microbiol 2022; 118:155-174. [PMID: 35766104 DOI: 10.1111/mmi.14958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 11/28/2022]
Abstract
Kinesins are motor proteins found in all eukaryotic lineages that move along microtubules to mediate cellular processes such as mitosis and intracellular transport. In trypanosomatids, the kinesin superfamily has undergone a prominent expansion, resulting in one of the most diverse kinesin repertoires that includes the two kinetoplastid-restricted families X1 and X2. Here, we characterize in Trypanosoma brucei TbKifX2A, an orphaned X2 kinesin. TbKifX2A tightly interacts with TbPH1, a kinesin-like protein with a likely inactive motor domain, a rarely reported occurrence. Both TbKifX2A and TbPH1 localize to the microtubule quartet (MtQ), a characteristic but poorly understood cytoskeletal structure that wraps around the flagellar pocket as it extends to the cell body anterior. The proximal proteome of TbPH1 revealed two other interacting proteins, the flagellar pocket protein FP45 and intriguingly another X2 kinesin, TbKifX2C. Simultaneous ablation of TbKifX2A/TbPH1 results in the depletion of FP45 and TbKifX2C and also an expansion of the flagellar pocket, among other morphological defects. TbKifX2A is the first motor protein to be localized to the MtQ. The observation that TbKifX2C also associates with the MtQ suggests that the X2 kinesin family may have co-evolved with the MtQ, both kinetoplastid-specific traits.
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Affiliation(s)
- Corinna Benz
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia
| | - Nora Müller
- Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Sabine Kaltenbrunner
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia.,Johannes Kepler University, Medical Faculty, Linz, Austria
| | - Hana Váchová
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Marie Vancová
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Julius Lukeš
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
| | - Vladimír Varga
- Laboratory of Cell Motility, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czechia
| | - Hassan Hashimi
- Institute of Parasitology, Biology Center, Czech Academy of Sciences, České Budějovice, Czechia.,Faculty of Science, University of South Bohemia, České Budějovice, Czechia
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7
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A Spef1-interacting microtubule quartet protein in Trypanosoma brucei promotes flagellar inheritance by regulating basal body segregation. J Biol Chem 2022; 298:102125. [PMID: 35697071 PMCID: PMC9257412 DOI: 10.1016/j.jbc.2022.102125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 11/24/2022] Open
Abstract
The human parasite Trypanosoma brucei contains a motile flagellum that determines the plane of cell division, controls cell morphology, and mediates cell-cell communication. During the cell cycle, inheritance of the newly formed flagellum requires its correct positioning toward the posterior of the cell, which depends on the faithful segregation of multiple flagellum-associated cytoskeletal structures including the basal body, the flagellar pocket collar, the flagellum attachment zone, and the hook complex. A specialized group of four microtubules termed the microtubule quartet (MtQ) originates from the basal body and runs through the flagellar pocket collar and the hook complex to extend, along the flagellum attachment zone, toward the anterior of the cell. However, the physiological function of the MtQ is poorly understood, and few MtQ-associated proteins have been identified and functionally characterized. We report here that an MtQ-localized protein named NHL1 interacts with the microtubule-binding protein TbSpef1 and depends on TbSpef1 for its localization to the MtQ. We show that RNAi-mediated knockdown of NHL1 impairs the segregation of flagellum-associated cytoskeletal structures, resulting in mispositioning of the new flagellum. Furthermore, knockdown of NHL1 also causes misplacement of the cell division plane in dividing trypanosome cells, halts cleavage furrow ingression, and inhibits completion of cytokinesis. These findings uncover a crucial role for the MtQ-associated protein NHL1 in regulating basal body segregation to promote flagellar inheritance in T. brucei.
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8
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Ramanantsalama MR, Landrein N, Casas E, Salin B, Blancard C, Bonhivers M, Robinson DR, Dacheux D. TFK1, a basal body transition fibre protein that is essential for cytokinesis in Trypanosoma brucei. J Cell Sci 2022; 135:275643. [PMID: 35588197 DOI: 10.1242/jcs.259893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
In Trypanosoma brucei, transition fibres (TF) form a nine-bladed pattern-like structure connecting the base of the flagellum to the flagellar pocket membrane. Despite the characterization of two TF proteins, CEP164C and TbRP2, little is known about the organization of these fibres. Here, we report the identification and characterization of the first kinetoplastid-specific TF protein named TFK1 (Tb927.6.1180). Bioinformatics and functional domain analysis identified three TFK1 distinct domains: an N-terminal domain of an unpredicted function, a coiled-coil domain involved in TFK1-TFK1 interaction and a C-terminal intrinsically disordered region potentially involved in protein interaction. Cellular immuno-localization showed that TFK1 is a newly identified basal body maturation marker. Further, using ultrastructure expansion and immuno-electron microscopies we localized CEP164C and TbRP2 at the TF and TFK1 on the distal appendage matrix of the TF. Importantly, RNAi knockdown of TFK1 in bloodstream form cells induced misplacement of basal bodies, a defect in the furrow or fold generation and eventually cell death. We hypothesize that TFK1 is a basal body positioning specific actor and a key regulator of cytokinesis in the bloodstream form Trypanosoma brucei.
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Affiliation(s)
| | - Nicolas Landrein
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Elina Casas
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Bénédicte Salin
- University of Bordeaux, CNRS, Microscopy Department IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Corinne Blancard
- University of Bordeaux, CNRS, Microscopy Department IBGC, UMR 5095, F-33000 Bordeaux, France
| | - Mélanie Bonhivers
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Derrick R Robinson
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
| | - Denis Dacheux
- University of Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France.,Bordeaux INP, Microbiologie Fondamentale et Pathogénicité, UMR 5234, F-33000 Bordeaux, France
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9
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Cavalier-Smith T. Ciliary transition zone evolution and the root of the eukaryote tree: implications for opisthokont origin and classification of kingdoms Protozoa, Plantae, and Fungi. PROTOPLASMA 2022; 259:487-593. [PMID: 34940909 PMCID: PMC9010356 DOI: 10.1007/s00709-021-01665-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 05/03/2021] [Indexed: 05/19/2023]
Abstract
I thoroughly discuss ciliary transition zone (TZ) evolution, highlighting many overlooked evolutionarily significant ultrastructural details. I establish fundamental principles of TZ ultrastructure and evolution throughout eukaryotes, inferring unrecognised ancestral TZ patterns for Fungi, opisthokonts, and Corticata (i.e., kingdoms Plantae and Chromista). Typical TZs have a dense transitional plate (TP), with a previously overlooked complex lattice as skeleton. I show most eukaryotes have centriole/TZ junction acorn-V filaments (whose ancestral function was arguably supporting central pair microtubule-nucleating sites; I discuss their role in centriole growth). Uniquely simple malawimonad TZs (without TP, simpler acorn) pinpoint the eukaryote tree's root between them and TP-bearers, highlighting novel superclades. I integrate TZ/ciliary evolution with the best multiprotein trees, naming newly recognised major eukaryote clades and revise megaclassification of basal kingdom Protozoa. Recent discovery of non-photosynthetic phagotrophic flagellates with genome-free plastids (Rhodelphis), the sister group to phylum Rhodophyta (red algae), illuminates plant and chromist early evolution. I show previously overlooked marked similarities in cell ultrastructure between Rhodelphis and Picomonas, formerly considered an early diverging chromist. In both a nonagonal tube lies between their TP and an annular septum surrounding their 9+2 ciliary axoneme. Mitochondrial dense condensations and mitochondrion-linked smooth endomembrane cytoplasmic partitioning cisternae further support grouping Picomonadea and Rhodelphea as new plant phylum Pararhoda. As Pararhoda/Rhodophyta form a robust clade on site-heterogeneous multiprotein trees, I group Pararhoda and Rhodophyta as new infrakingdom Rhodaria of Plantae within subkingdom Biliphyta, which also includes Glaucophyta with fundamentally similar TZ, uniquely in eukaryotes. I explain how biliphyte TZs generated viridiplant stellate-structures.
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10
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A specific basal body linker protein provides the connection function for basal body inheritance in trypanosomes. Proc Natl Acad Sci U S A 2021; 118:2014040118. [PMID: 33597294 DOI: 10.1073/pnas.2014040118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Centrioles and basal bodies (CBBs) are found in physically linked pairs, and in mammalian cells intercentriole connections (G1-G2 tether and S-M linker) regulate centriole duplication and function. In trypanosomes BBs are not associated with the spindle and function in flagellum/cilia nucleation with an additional role in mitochondrial genome (kinetoplast DNA [kDNA]) segregation. Here, we describe BBLP, a BB/pro-BB (pBB) linker protein in Trypanosoma brucei predicted to be a large coiled-coil protein conserved in the kinetoplastida. Colocalization with the centriole marker SAS6 showed that BBLP localizes between the BB/pBB pair, throughout the cell cycle, with a stronger signal in the old flagellum BB/pBB pair. Importantly, RNA interference (RNAi) depletion of BBLP leads to a conspicuous splitting of the BB/pBB pair associated only with the new flagellum. BBLP RNAi is lethal in the bloodstream form of the parasite and perturbs mitochondrial kDNA inheritance. Immunogold labeling confirmed that BBLP is localized to a cytoskeletal component of the BB/pBB linker, and tagged protein induction showed that BBLP is incorporated de novo in both new and old flagella BB pairs of dividing cells. We show that the two aspects of CBB disengagement-loss of orthogonal orientation and ability to separate and move apart-are consistent but separable events in evolutionarily diverse cells and we provide a unifying model explaining centriole/BB linkage differences between such cells.
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11
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Campbell PC, de Graffenried CL. Alternate histories of cytokinesis: lessons from the trypanosomatids. Mol Biol Cell 2021; 31:2631-2639. [PMID: 33180676 PMCID: PMC7927182 DOI: 10.1091/mbc.e19-12-0696] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Popular culture has recently produced several “alternate histories” that describe worlds where key historical events had different outcomes. Beyond entertainment, asking “could this have happened a different way?” and “what would the consequences be?” are valuable approaches for exploring molecular mechanisms in many areas of research, including cell biology. Analogous to alternate histories, studying how the evolutionary trajectories of related organisms have been selected to provide a range of outcomes can tell us about the plasticity and potential contained within the genome of the ancestral cell. Among eukaryotes, a group of model organisms has been employed with great success to identify a core, conserved framework of proteins that segregate the duplicated cellular organelles into two daughter cells during cell division, a process known as cytokinesis. However, these organisms provide relatively sparse sampling across the broad evolutionary distances that exist, which has limited our understanding of the true potential of the ancestral eukaryotic toolkit. Recent work on the trypanosomatids, a group of eukaryotic parasites, exemplifies alternate historical routes for cytokinesis that illustrate the range of eukaryotic diversity, especially among unicellular organisms.
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Affiliation(s)
- Paul C Campbell
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
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12
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Casein kinase TbCK1.2 regulates division of kinetoplast DNA, and movement of basal bodies in the African trypanosome. PLoS One 2021; 16:e0249908. [PMID: 33861760 PMCID: PMC8051774 DOI: 10.1371/journal.pone.0249908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 03/26/2021] [Indexed: 01/15/2023] Open
Abstract
The single mitochondrial nucleoid (kinetoplast) of Trypanosoma brucei is found proximal to a basal body (mature (mBB)/probasal body (pBB) pair). Kinetoplast inheritance requires synthesis of, and scission of kinetoplast DNA (kDNA) generating two kinetoplasts that segregate with basal bodies into daughter cells. Molecular details of kinetoplast scission and the extent to which basal body separation influences the process are unavailable. To address this topic, we followed basal body movements in bloodstream trypanosomes following depletion of protein kinase TbCK1.2 which promotes kinetoplast division. In control cells we found that pBBs are positioned 0.4 um from mBBs in G1, and they mature after separating from mBBs by at least 0.8 um: mBB separation reaches ~2.2 um. These data indicate that current models of basal body biogenesis in which pBBs mature in close proximity to mBBs may need to be revisited. Knockdown of TbCK1.2 produced trypanosomes containing one kinetoplast and two nuclei (1K2N), increased the percentage of cells with uncleaved kDNA 400%, decreased mBB spacing by 15%, and inhibited cytokinesis 300%. We conclude that (a) separation of mBBs beyond a threshold of 1.8 um correlates with division of kDNA, and (b) TbCK1.2 regulates kDNA scission. We propose a Kinetoplast Division Factor hypothesis that integrates these data into a pathway for biogenesis of two daughter mitochondrial nucleoids.
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Halliday C, de Castro-Neto A, Alcantara CL, Cunha-E-Silva NL, Vaughan S, Sunter JD. Trypanosomatid Flagellar Pocket from Structure to Function. Trends Parasitol 2021; 37:317-329. [PMID: 33308952 DOI: 10.1016/j.pt.2020.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023]
Abstract
The trypanosomatids Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. are flagellate eukaryotic parasites that cause serious diseases in humans and animals. These parasites have cell shapes defined by a subpellicular microtubule array and all share a number of important cellular features. One of these is the flagellar pocket, an invagination of the cell membrane around the proximal end of the flagellum, which is an important organelle for endo/exocytosis. The flagellar pocket plays a crucial role in parasite pathogenicity and persistence in the host and has a great influence on cell morphogenesis and cell division. Here, we compare the morphology and function of the flagellar pockets between different trypanosomatids, with their life cycles and ecological niches likely influencing these differences.
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Affiliation(s)
- Clare Halliday
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Artur de Castro-Neto
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Carolina L Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Narcisa L Cunha-E-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-902, Brazil; Centro Nacional de Biologia Estrutural e Bioimagem (CENABIO), Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Jack D Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK.
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14
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An T, Hu H, Li Z. The kinetoplastid-specific phosphatase KPP1 attenuates PLK activity to facilitate flagellum inheritance in Trypanosoma brucei. Sci Signal 2021; 14:14/669/eabc6435. [PMID: 33563698 DOI: 10.1126/scisignal.abc6435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Trypanosoma brucei, an important human parasite, has a flagellum that controls cell motility, morphogenesis, proliferation, and cell-cell communication. Inheritance of the newly assembled flagellum during the cell cycle requires the Polo-like kinase homolog TbPLK and the kinetoplastid-specific protein phosphatase KPP1, although whether TbPLK acts on KPP1 or vice versa has been unclear. Here, we showed that dephosphorylation of TbPLK on Thr125 by KPP1 maintained low TbPLK activity in the flagellum-associated hook complex structure, thereby ensuring proper flagellum positioning and attachment. This dephosphorylation event required the recognition of phosphorylated Thr198 in the activation loop of TbPLK by the N-terminal Plus3 domain of KPP1 and the dephosphorylation of phosphorylated Thr125 in TbPLK by the C-terminal catalytic domain of KPP1. Dephosphorylation of TbPLK by KPP1 prevented hyperphosphorylation of the hook complex protein TbCentrin2, thereby allowing timely dephosphorylation of phosphorylated TbCentrin2 for hook complex duplication and flagellum positioning and attachment. Thus, KPP1 attenuates TbPLK activity by dephosphorylating TbPLK to facilitate flagellum inheritance.
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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
| | - Huiqing Hu
- 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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15
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Kurasawa Y, An T, Li Z. Polo-like kinase in trypanosomes: an odd member out of the Polo family. Open Biol 2020; 10:200189. [PMID: 33050792 PMCID: PMC7653357 DOI: 10.1098/rsob.200189] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/17/2020] [Indexed: 12/12/2022] Open
Abstract
Polo-like kinases (Plks) are evolutionarily conserved serine/threonine protein kinases playing crucial roles during multiple stages of mitosis and cytokinesis in yeast and animals. Plks are characterized by a unique Polo-box domain, which plays regulatory roles in controlling Plk activation, interacting with substrates and targeting Plk to specific subcellular locations. Plk activity and protein abundance are subject to temporal and spatial control through transcription, phosphorylation and proteolysis. In the early branching protists, Plk orthologues are present in some taxa, such as kinetoplastids and Giardia, but are lost in apicomplexans, such as Plasmodium. Works from characterizing a Plk orthologue in Trypanosoma brucei, a kinetoplastid protozoan, discover its essential roles in regulating the inheritance of flagellum-associated cytoskeleton and the initiation of cytokinesis, but not any stage of mitosis. These studies reveal evolutionarily conserved and species-specific features in the control of Plk activation, substrate recognition and protein abundance, and suggest the divergence of Plk function and regulation for specialized needs in this flagellated unicellular eukaryote.
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Affiliation(s)
| | | | - 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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16
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Trépout S. In situ structural analysis of the flagellum attachment zone in Trypanosoma brucei using cryo-scanning transmission electron tomography. JOURNAL OF STRUCTURAL BIOLOGY-X 2020; 4:100033. [PMID: 32775999 PMCID: PMC7394968 DOI: 10.1016/j.yjsbx.2020.100033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 07/06/2020] [Accepted: 07/16/2020] [Indexed: 11/26/2022]
Abstract
Flagellar and cellular membranes are in close contact next to the FAZ filament. Sticks are heterogeneously distributed along the FAZ filament length. Thin appendages are present between the sticks and the neighbouring microtubules. The FAZ could elongate thanks to the action of dynein on subpellicular microtubules.
The flagellum of Trypanosoma brucei is a 20 µm-long organelle responsible for locomotion and cell morphogenesis. The flagellum attachment zone (FAZ) is a multi-protein complex whose function is to attach the flagellum to the cell body but also to guide cytokinesis. Cryo-transmission electron microscopy is a tool of choice to access the structure of the FAZ in a close-to-native state. However, because of the large dimension of the cell body, the whole FAZ cannot be structurally studied in situ at the nanometre scale in 3D using classical transmission electron microscopy approaches. In the present work, cryo-scanning transmission electron tomography, a new method capable of investigating cryo-fixed thick biological samples, has been used to study whole T. brucei cells at the bloodstream stage. The method has been used to visualise and characterise the structure and organisation of the FAZ filament. It is composed of an array of cytoplasmic stick-like structures. These sticks are heterogeneously distributed between the posterior part and the anterior tip of the cell. This cryo-STET investigation provides new insights into the structure of the FAZ filament. In combination with protein structure predictions, this work proposes a new model for the elongation of the FAZ.
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Douglas RL, Haltiwanger BM, Albisetti A, Wu H, Jeng RL, Mancuso J, Cande WZ, Welch MD. Trypanosomes have divergent kinesin-2 proteins that function differentially in flagellum biosynthesis and cell viability. J Cell Sci 2020; 133:jcs129213. [PMID: 32503938 DOI: 10.1242/jcs.129213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
Trypanosoma brucei, the causative agent of African sleeping sickness, has a flagellum that is crucial for motility, pathogenicity, and viability. In most eukaryotes, the intraflagellar transport (IFT) machinery drives flagellum biogenesis, and anterograde IFT requires kinesin-2 motor proteins. In this study, we investigated the function of the two T. brucei kinesin-2 proteins, TbKin2a and TbKin2b, in bloodstream form trypanosomes. We found that, compared to kinesin-2 proteins across other phyla, TbKin2a and TbKin2b show greater variation in neck, stalk and tail domain sequences. Both kinesins contributed additively to flagellar lengthening. Silencing TbKin2a inhibited cell proliferation, cytokinesis and motility, whereas silencing TbKin2b did not. TbKin2a was localized on the flagellum and colocalized with IFT components near the basal body, consistent with it performing a role in IFT. TbKin2a was also detected on the flagellar attachment zone, a specialized structure that connects the flagellum to the cell body. Our results indicate that kinesin-2 proteins in trypanosomes play conserved roles in flagellar biosynthesis and exhibit a specialized localization, emphasizing the evolutionary flexibility of motor protein function in an organism with a large complement of kinesins.
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Affiliation(s)
- Robert L Douglas
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Brett M Haltiwanger
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Anna Albisetti
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Haiming Wu
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Robert L Jeng
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Joel Mancuso
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - W Zacheus Cande
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
| | - Matthew D Welch
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720, USA
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18
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Lemos M, Mallet A, Bertiaux E, Imbert A, Rotureau B, Bastin P. Timing and original features of flagellum assembly in trypanosomes during development in the tsetse fly. Parasit Vectors 2020; 13:169. [PMID: 32248844 PMCID: PMC7132888 DOI: 10.1186/s13071-020-04026-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 03/17/2020] [Indexed: 02/07/2023] Open
Abstract
Background Trypanosoma brucei exhibits a complex life-cycle alternating between tsetse flies and mammalian hosts. When parasites infect the fly, cells differentiate to adapt to life in various tissues, which is accompanied by drastic morphological and biochemical modifications especially in the proventriculus. This key step represents a bottleneck for salivary gland infection. Methods Here, we monitored flagellum assembly in trypanosomes during differentiation from the trypomastigote to the epimastigote stage, i.e. when the nucleus migrates to the posterior end of the cell, by using three-dimensional electron microscopy (focused ion beam scanning electron microscopy, FIB-SEM) and immunofluorescence assays. Results The combination of light and electron microscopy approaches provided structural and molecular evidence that the new flagellum is assembled while the nucleus migrates towards the posterior region of the body. Two major differences with well-known procyclic cells are reported. First, growth of the new flagellum begins when the associated basal body is found in a posterior position relative to the mature flagellum. Secondly, the new flagellum acquires its own flagellar pocket before rotating on the left side of the anterior-posterior axis. FIB-SEM revealed the presence of a structure connecting the new and mature flagellum and serial sectioning confirmed morphological similarities with the flagella connector of procyclic cells. We discuss the potential function of the flagella connector in trypanosomes from the proventriculus. Conclusions These findings show that T. brucei finely modulates its cytoskeletal components to generate highly variable morphologies.![]()
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Affiliation(s)
- Moara Lemos
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France
| | - Adeline Mallet
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.,UtechS Ultrastructural Bioimaging (Ultrapole), C2RT, Institut Pasteur, 75015, Paris, France.,Sorbonne Université école doctorale Complexité du Vivant, ED 515, 7, quai Saint-Bernard, case 32, 75252, Paris Cedex 05, France
| | - Eloïse Bertiaux
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.,Sorbonne Université école doctorale Complexité du Vivant, ED 515, 7, quai Saint-Bernard, case 32, 75252, Paris Cedex 05, France
| | | | - Brice Rotureau
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Institut Pasteur & INSERM U1201, 25, rue du Docteur Roux, 75015, Paris, France.
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19
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Pham KTM, Li Z. Regulated protein stabilization underpins the functional interplay among basal body components in Trypanosoma brucei. J Biol Chem 2020; 295:729-742. [PMID: 31819011 DOI: 10.1074/jbc.ra119.011352] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/03/2019] [Indexed: 11/06/2022] Open
Abstract
The basal body in the human parasite Trypanosoma brucei is structurally equivalent to the centriole in animals and functions in the nucleation of axonemal microtubules in the flagellum. T. brucei lacks many evolutionarily conserved centriolar protein homologs and constructs the basal body through unknown mechanisms. Two evolutionarily conserved centriole/basal body cartwheel proteins, TbSAS-6 and TbBLD10, and a trypanosome-specific protein, BBP65, play essential roles in basal body biogenesis in T. brucei, but how they cooperate in the regulation of basal body assembly remains elusive. Here using RNAi, endogenous epitope tagging, immunofluorescence microscopy, and 3D-structured illumination super-resolution microscopy, we identified a new trypanosome-specific protein named BBP164 and found that it has an essential role in basal body biogenesis in T. brucei Further investigation of the functional interplay among BBP164 and the other three regulators of basal body assembly revealed that BBP164 and BBP65 are interdependent for maintaining their stability and depend on TbSAS-6 and TbBLD10 for their stabilization in the basal body. Additionally, TbSAS-6 and TbBLD10 are independent from each other and from BBP164 and BBP65 for maintaining their stability in the basal body. These findings demonstrate that basal body cartwheel proteins are required for stabilizing other basal body components and uncover that regulation of protein stability is an unusual control mechanism for assembly of the basal body in T. brucei.
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Affiliation(s)
- Kieu T M Pham
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas 77030
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20
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Regulated protein stabilization underpins the functional interplay among basal body components in Trypanosoma brucei. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49931-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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21
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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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22
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Tomographic Collection of Block-Based Sparse STEM Images: Practical Implementation and Impact on the Quality of the 3D Reconstructed Volume. MATERIALS 2019; 12:ma12142281. [PMID: 31315199 PMCID: PMC6679239 DOI: 10.3390/ma12142281] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 01/18/2023]
Abstract
The reduction of the electron dose in electron tomography of biological samples is of high significance to diminish radiation damages. Simulations have shown that sparse data collection can perform efficient electron dose reduction. Frameworks based on compressive-sensing or inpainting algorithms have been proposed to accurately reconstruct missing information in sparse data. The present work proposes a practical implementation to perform tomographic collection of block-based sparse images in scanning transmission electron microscopy. The method has been applied on sections of chemically-fixed and resin-embedded Trypanosoma brucei cells. There are 3D reconstructions obtained from various amounts of downsampling, which are compared and eventually the limits of electron dose reduction using this method are explored.
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23
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Indirubin Analogues Inhibit Trypanosoma brucei Glycogen Synthase Kinase 3 Short and T. brucei Growth. Antimicrob Agents Chemother 2019; 63:AAC.02065-18. [PMID: 30910902 DOI: 10.1128/aac.02065-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 03/14/2019] [Indexed: 12/12/2022] Open
Abstract
The protozoan parasite Trypanosoma brucei is the causative agent of human African trypanosomiasis (HAT). The disease is fatal if it remains untreated, whereas most drug treatments are inadequate due to high toxicity, difficulties in administration, and low central nervous system penetration. T. brucei glycogen synthase kinase 3 short (TbGSK3s) is essential for parasite survival and thus represents a potential drug target that could be exploited for HAT treatment. Indirubins, effective leishmanicidals, provide a versatile scaffold for the development of potent GSK3 inhibitors. Herein, we report on the screening of 69 indirubin analogues against T. brucei bloodstream forms. Of these, 32 compounds had potent antitrypanosomal activity (half-maximal effective concentration = 0.050 to 3.2 μM) and good selectivity for the analogues over human HepG2 cells (range, 7.4- to over 641-fold). The majority of analogues were potent inhibitors of TbGSK3s, and correlation studies for an indirubin subset, namely, the 6-bromosubstituted 3'-oxime bearing an extra bulky substituent on the 3' oxime [(6-BIO-3'-bulky)-substituted indirubins], revealed a positive correlation between kinase inhibition and antitrypanosomal activity. Insights into this indirubin-TbGSK3s interaction were provided by structure-activity relationship studies. Comparison between 6-BIO-3'-bulky-substituted indirubin-treated parasites and parasites silenced for TbGSK3s by RNA interference suggested that the above-described compounds may target TbGSK3s in vivo To further understand the molecular basis of the growth arrest brought about by the inhibition or ablation of TbGSK3s, we investigated the intracellular localization of TbGSK3s. TbGSK3s was present in cytoskeletal structures, including the flagellum and basal body area. Overall, these results give insights into the mode of action of 6-BIO-3'-bulky-substituted indirubins that are promising hits for antitrypanosomal drug discovery.
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Cayla M, Rojas F, Silvester E, Venter F, Matthews KR. African trypanosomes. Parasit Vectors 2019; 12:190. [PMID: 31036044 PMCID: PMC6489224 DOI: 10.1186/s13071-019-3355-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/26/2019] [Indexed: 12/15/2022] Open
Abstract
African trypanosomes cause human African trypanosomiasis and animal African trypanosomiasis. They are transmitted by tsetse flies in sub-Saharan Africa. Although most famous for their mechanisms of immune evasion by antigenic variation, there have been recent important studies that illuminate important aspects of the biology of these parasites both in their mammalian host and during passage through their tsetse fly vector. This Primer overviews current research themes focused on these parasites and discusses how these biological insights and the development of new technologies to interrogate gene function are being used in the search for new approaches to control the parasite. The new insights into the biology of trypanosomes in their host and vector highlight that we are in a ‘golden age’ of discovery for these fascinating parasites.
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Affiliation(s)
- Mathieu Cayla
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Federico Rojas
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Frank Venter
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
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25
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Nnadi CO, Ebiloma GU, Black JA, Nwodo NJ, Lemgruber L, Schmidt TJ, de Koning HP. Potent Antitrypanosomal Activities of 3-Aminosteroids against African Trypanosomes: Investigation of Cellular Effects and of Cross-Resistance with Existing Drugs. Molecules 2019; 24:E268. [PMID: 30642032 PMCID: PMC6359104 DOI: 10.3390/molecules24020268] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 11/16/2022] Open
Abstract
Treatment of animal African trypanosomiasis (AAT) requires urgent need for safe, potent and affordable drugs and this has necessitated this study. We investigated the trypanocidal activities and mode of action of selected 3-aminosteroids against Trypanosoma brucei brucei. The in vitro activity of selected compounds of this series against T. congolense (Savannah-type, IL3000), T. b. brucei (bloodstream trypomastigote, Lister strain 427 wild-type (427WT)) and various multi-drug resistant cell lines was assessed using a resazurin-based cell viability assay. Studies on mode of antitrypanosomal activity of some selected 3-aminosteroids against Tbb 427WT were also carried out. The tested compounds mostly showed moderate-to-low in vitro activities and low selectivity to mammalian cells. Interestingly, a certain aminosteroid, holarrhetine (10, IC50 = 0.045 ± 0.03 µM), was 2 times more potent against T. congolense than the standard veterinary drug, diminazene aceturate, and 10 times more potent than the control trypanocide, pentamidine, and displayed an excellent in vitro selectivity index of 2130 over L6 myoblasts. All multi-drug resistant strains of T. b. brucei tested were not significantly cross-resistant with the purified compounds. The growth pattern of Tbb 427WT on long and limited exposure time revealed gradual but irrecoverable growth arrest at ≥ IC50 concentrations of 3-aminosteroids. Trypanocidal action was not associated with membrane permeabilization of trypanosome cells but instead with mitochondrial membrane depolarization, reduced adenosine triphosphate (ATP) levels and G₂/M cell cycle arrest which appear to be the result of mitochondrial accumulation of the aminosteroids. These findings provided insights for further development of this new and promising class of trypanocide against African trypanosomes.
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Affiliation(s)
- Charles O Nnadi
- Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of Münster, Pharma Campus Corrensstraße 48, D-48149 Münster, Germany.
- Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Nigeria Nsukka, Enugu 410001, Nigeria.
| | - Godwin U Ebiloma
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto 606-8585, Japan.
| | - Jennifer A Black
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK.
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil.
| | - Ngozi J Nwodo
- Department of Pharmaceutical and Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Nigeria Nsukka, Enugu 410001, Nigeria.
| | - Leandro Lemgruber
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
| | - Thomas J Schmidt
- Institute of Pharmaceutical Biology and Phytochemistry (IPBP), University of Münster, Pharma Campus Corrensstraße 48, D-48149 Münster, Germany.
| | - Harry P de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8TA, UK.
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Sunter JD, Moreira-Leite F, Gull K. Dependency relationships between IFT-dependent flagellum elongation and cell morphogenesis in Leishmania. Open Biol 2018; 8:rsob.180124. [PMID: 30463910 PMCID: PMC6282073 DOI: 10.1098/rsob.180124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 10/26/2018] [Indexed: 01/03/2023] Open
Abstract
Flagella have multiple functions that are associated with different axonemal structures. Motile flagella typically have a 9 + 2 arrangement of microtubules, whereas sensory flagella normally have a 9 + 0 arrangement. Leishmania exhibits both of these flagellum forms and differentiation between these two flagellum forms is associated with cytoskeletal and cell shape changes. We disrupted flagellum elongation in Leishmania by deleting the intraflagellar transport (IFT) protein IFT140 and examined the effects on cell morphogenesis. Δift140 cells have no external flagellum, having only a very short flagellum within the flagellar pocket. This short flagellum had a collapsed 9 + 0 (9v) axoneme configuration reminiscent of that in the amastigote and was not attached to the pocket membrane. Although amastigote-like changes occurred in the flagellar cytoskeleton, the cytoskeletal structures of Δift140 cells retained their promastigote configurations, as examined by fluorescence microscopy of tagged proteins and serial electron tomography. Thus, Leishmania promastigote cell morphogenesis does not depend on the formation of a long flagellum attached at the neck. Furthermore, our data show that disruption of the IFT system is sufficient to produce a switch from the 9 + 2 to the collapsed 9 + 0 (9v) axonemal structure, echoing the process that occurs during the promastigote to amastigote differentiation.
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Affiliation(s)
- Jack Daniel Sunter
- Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Oxford OX3 0BP, UK
| | - Flavia Moreira-Leite
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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Boundary behaviours of Leishmania mexicana: A hydrodynamic simulation study. J Theor Biol 2018; 462:311-320. [PMID: 30465777 PMCID: PMC6333917 DOI: 10.1016/j.jtbi.2018.11.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023]
Abstract
It is well established that the parasites of the genus Leishmania exhibit complex surface interactions with the sandfly vector midgut epithelium, but no prior study has considered the details of their hydrodynamics. Here, the boundary behaviours of motile Leishmania mexicana promastigotes are explored in a computational study using the boundary element method, with a model flagellar beating pattern that has been identified from digital videomicroscopy. In particular a simple flagellar kinematics is observed and quantified using image processing and mode identification techniques, suggesting a simple mechanical driver for the Leishmania beat. Phase plane analysis and long-time simulation of a range of Leishmania swimming scenarios demonstrate an absence of stable boundary motility for an idealised model promastigote, with behaviours ranging from boundary capture to deflection into the bulk both with and without surface forces between the swimmer and the boundary. Indeed, the inclusion of a short-range repulsive surface force results in the deflection of all surface-bound promastigotes, suggesting that the documented surface detachment of infective metacyclic promastigotes may be the result of their particular morphology and simple hydrodynamics. Further, simulation elucidates a remarkable morphology-dependent hydrodynamic mechanism of boundary approach, hypothesised to be the cause of the well-established phenomenon of tip-first epithelial attachment of Leishmania promastigotes to the sandfly vector midgut.
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Wiedeman J, Mensa-Wilmot K. A fixable probe for visualizing flagella and plasma membranes of the African trypanosome. PLoS One 2018; 13:e0197541. [PMID: 29768499 PMCID: PMC5955550 DOI: 10.1371/journal.pone.0197541] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/03/2018] [Indexed: 12/22/2022] Open
Abstract
The protozoan Trypanosoma brucei sp. cause diseases in humans and animals. Studies of T. brucei cell biology have revealed unique features, such as major endocytic events being limited to a single region, and mitochondrial genome segregation mediated via basal bodies. Further understanding of trypanosome cell biology can be facilitated with super-resolution fluorescence microscopy. Lack of a plasma membrane probe for fixed trypanosomes remains a persistent problem in need of a working solution. Herein, we report protocols developed using mCLING in super-resolution structured illumination fluorescence microscopy (SR-SIM). mCLING comprehensively labels flagellar membranes, including nascent intracellular stages. To extend its usefulness for trypanosome biology we optimized mCLING in combination with organelle-specific antibodies for immunofluorescence of basal bodies or mitochondria. Then in work with live trypanosomes, we demonstrated internalization of mCLING into endocytic stations that overlap with LysoTracker in acidic organelles. Greater detail of the intracellular location of mCLING was obtained with SR-SIM after pulsing trypanosomes with the probe, and allowing continuous uptake of fluorescent concanavalin A (ConA) destined for lysosomes. In most cases, ConA and mCLING vesicles were juxtaposed but not coincident. A video of the complete image stack at the 15 min time point shows zones of mCLING staining surrounding patches of ConA, consistent with persistence of mCLING in membranes of compartments that contain luminal ConA. In summary, these studies establish mCLING as a versatile trypanosome membrane probe compatible with super-resolution microscopy that can be used for detailed analysis of flagellar membrane biogenesis. In addition, mCLING can be used for immunofluorescence in fixed, permeabilized trypanosomes. Its robust staining of the plasma membrane eliminates a need to overlay transmitted light images on fluorescence pictures obtained from widefield, confocal, or super-resolution microscopy.
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Affiliation(s)
- Justin Wiedeman
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
| | - Kojo Mensa-Wilmot
- Department of Cellular Biology, University of Georgia, Athens, Georgia, United States of America
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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Perry JA, Sinclair-Davis AN, McAllaster MR, de Graffenried CL. TbSmee1 regulates hook complex morphology and the rate of flagellar pocket uptake in Trypanosoma brucei. Mol Microbiol 2018; 107:344-362. [PMID: 29178204 PMCID: PMC5777864 DOI: 10.1111/mmi.13885] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/20/2017] [Accepted: 11/22/2017] [Indexed: 01/26/2023]
Abstract
Trypanosoma brucei uses multiple mechanisms to evade detection by its insect and mammalian hosts. The flagellar pocket (FP) is the exclusive site of uptake from the environment in trypanosomes and shields receptors from exposure to the host. The FP neck is tightly associated with the flagellum via a series of cytoskeletal structures that include the hook complex (HC) and the centrin arm. These structures are implicated in facilitating macromolecule entry into the FP and nucleating the flagellum attachment zone (FAZ), which adheres the flagellum to the cell surface. TbSmee1 (Tb927.10.8820) is a component of the HC and a putative substrate of polo-like kinase (TbPLK), which is essential for centrin arm and FAZ duplication. We show that depletion of TbSmee1 in the insect-resident (procyclic) form of the parasite causes a 40% growth decrease and the appearance of multinucleated cells that result from defective cytokinesis. Cells lacking TbSmee1 contain HCs with aberrant morphology and show delayed uptake of both fluid-phase and membrane markers. TbPLK localization to the tip of the new FAZ is also blocked. These results argue that TbSmee1 is necessary for maintaining HC morphology, which is important for the parasite's ability to take up molecules from its environment.
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Affiliation(s)
- Jenna A. Perry
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Amy N. Sinclair-Davis
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
| | - Michael R. McAllaster
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, USA
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Morriswood B, Engstler M. Let's get fISSical: fast in silico synchronization as a new tool for cell division cycle analysis. Parasitology 2018; 145:196-209. [PMID: 28166845 PMCID: PMC5964468 DOI: 10.1017/s0031182017000038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/23/2016] [Accepted: 01/05/2017] [Indexed: 12/23/2022]
Abstract
Cell cycle progression is a question of fundamental biological interest. The coordinated duplication and segregation of all cellular structures and organelles is however an extremely complex process, and one which remains only partially understood even in the most intensively researched model organisms. Trypanosomes are in an unusual position in this respect - they are both outstanding model systems for fundamental questions in eukaryotic cell biology, and pathogens that are the causative agents of three of the neglected tropical diseases. As a failure to successfully complete cell division will be deleterious or lethal, analysis of the cell division cycle is of relevance both to basic biology and drug design efforts. Cell division cycle analysis is however experimentally challenging, as the analysis of phenotypes associated with it remains hypothesis-driven and therefore biased. Current methods of analysis are extremely labour-intensive, and cell synchronization remains difficult and unreliable. Consequently, there exists a need - both in basic and applied trypanosome biology - for a global, unbiased, standardized and high-throughput analysis of cell division cycle progression. In this review, the requirements - both practical and computational - for such a system are considered and compared with existing techniques for cell cycle analysis.
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Affiliation(s)
- Brooke Morriswood
- Department of Cell & Developmental Biology,University of Würzburg,Biocentre, Am Hubland, 97074 Würzburg,Germany
| | - Markus Engstler
- Department of Cell & Developmental Biology,University of Würzburg,Biocentre, Am Hubland, 97074 Würzburg,Germany
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Trépout S, Tassin AM, Marco S, Bastin P. STEM tomography analysis of the trypanosome transition zone. J Struct Biol 2017; 202:51-60. [PMID: 29248600 DOI: 10.1016/j.jsb.2017.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 11/20/2017] [Accepted: 12/10/2017] [Indexed: 02/06/2023]
Abstract
The protist Trypanosoma brucei is an emerging model for the study of cilia and flagella. Here, we used scanning transmission electron microscopy (STEM) tomography to describe the structure of the trypanosome transition zone (TZ). At the base of the TZ, nine transition fibres irradiate from the B microtubule of each doublet towards the membrane. The TZ adopts a 9 + 0 structure throughout its length of ∼300 nm and its lumen contains an electron-dense structure. The proximal portion of the TZ has an invariant length of 150 nm and is characterised by a collarette surrounding the membrane and the presence of electron-dense material between the membrane and the doublets. The distal portion exhibits more length variation (from 55 to 235 nm) and contains typical Y-links. STEM analysis revealed a more complex organisation of the Y-links compared to what was reported by conventional transmission electron microscopy. Observation of the very early phase of flagellum assembly demonstrated that the proximal portion and the collarette are assembled early during construction. The presence of the flagella connector that maintains the tip of the new flagellum to the side of the old was confirmed and additional filamentous structures making contact with the membrane of the flagellar pocket were also detected. The structure and potential functions of the TZ in trypanosomes are discussed, as well as its mode of assembly.
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Affiliation(s)
- Sylvain Trépout
- Université Paris Sud, Université Paris-Saclay, CNRS UMR9187, F-91405 Orsay, France; INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France
| | - Anne-Marie Tassin
- Université Paris Sud, Université Paris-Saclay, CNRS UMR9187, F-91405 Orsay, France; INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France; Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette Cedex, France
| | - Sergio Marco
- Université Paris Sud, Université Paris-Saclay, CNRS UMR9187, F-91405 Orsay, France; INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, INSERM U1201, Institut Pasteur, 25 Rue du Docteur Roux, 75015 Paris, France.
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McDowell G, Rajadurai S, Levin M. From cytoskeletal dynamics to organ asymmetry: a nonlinear, regulative pathway underlies left-right patterning. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0409. [PMID: 27821521 DOI: 10.1098/rstb.2015.0409] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 12/25/2022] Open
Abstract
Consistent left-right (LR) asymmetry is a fundamental aspect of the bodyplan across phyla, and errors of laterality form an important class of human birth defects. Its molecular underpinning was first discovered as a sequential pathway of left- and right-sided gene expression that controlled positioning of the heart and visceral organs. Recent data have revised this picture in two important ways. First, the physical origin of chirality has been identified; cytoskeletal dynamics underlie the asymmetry of single-cell behaviour and patterning of the LR axis. Second, the pathway is not linear: early disruptions that alter the normal sidedness of upstream asymmetric genes do not necessarily induce defects in the laterality of the downstream genes or in organ situs Thus, the LR pathway is a unique example of two fascinating aspects of biology: the interplay of physics and genetics in establishing large-scale anatomy, and regulative (shape-homeostatic) pathways that correct molecular and anatomical errors over time. Here, we review aspects of asymmetry from its intracellular, cytoplasmic origins to the recently uncovered ability of the LR control circuitry to achieve correct gene expression and morphology despite reversals of key 'determinant' genes. We provide novel functional data, in Xenopus laevis, on conserved elements of the cytoskeleton that drive asymmetry, and comparatively analyse it together with previously published results in the field. Our new observations and meta-analysis demonstrate that despite aberrant expression of upstream regulatory genes, embryos can progressively normalize transcriptional cascades and anatomical outcomes. LR patterning can thus serve as a paradigm of how subcellular physics and gene expression cooperate to achieve developmental robustness of a body axis.This article is part of the themed issue 'Provocative questions in left-right asymmetry'.
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Affiliation(s)
- Gary McDowell
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Suvithan Rajadurai
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA.,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
| | - Michael Levin
- Biology Department, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA .,Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155-4243, USA
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Albisetti A, Florimond C, Landrein N, Vidilaseris K, Eggenspieler M, Lesigang J, Dong G, Robinson DR, Bonhivers M. Interaction between the flagellar pocket collar and the hook complex via a novel microtubule-binding protein in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006710. [PMID: 29091964 PMCID: PMC5683654 DOI: 10.1371/journal.ppat.1006710] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 11/13/2017] [Accepted: 10/24/2017] [Indexed: 12/16/2022] Open
Abstract
Trypanosoma brucei belongs to a group of unicellular, flagellated parasites that are responsible for human African trypanosomiasis. An essential aspect of parasite pathogenicity is cytoskeleton remodelling, which occurs during the life cycle of the parasite and is accompanied by major changes in morphology and organelle positioning. The flagellum originates from the basal bodies and exits the cell body through the flagellar pocket (FP) but remains attached to the cell body via the flagellum attachment zone (FAZ). The FP is an invagination of the pellicular membrane and is the sole site for endo- and exocytosis. The FAZ is a large complex of cytoskeletal proteins, plus an intracellular set of four specialised microtubules (MtQ) that elongate from the basal bodies to the anterior end of the cell. At the distal end of the FP, an essential, intracellular, cytoskeletal structure called the flagellar pocket collar (FPC) circumvents the flagellum. Overlapping the FPC is the hook complex (HC) (a sub-structure of the previously named bilobe) that is also essential and is thought to be involved in protein FP entry. BILBO1 is the only functionally characterised FPC protein and is necessary for FPC and FP biogenesis. Here, we used a combination of in vitro and in vivo approaches to identify and characterize a new BILBO1 partner protein-FPC4. We demonstrate that FPC4 localises to the FPC, the HC, and possibly to a proximal portion of the MtQ. We found that the C-terminal domain of FPC4 interacts with the BILBO1 N-terminal domain, and we identified the key amino acids required for this interaction. Interestingly, the FPC4 N-terminal domain was found to bind microtubules. Over-expression studies highlight the role of FPC4 in its association with the FPC, HC and FPC segregation. Our data suggest a tripartite association between the FPC, the HC and the MtQ.
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Affiliation(s)
- Anna Albisetti
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Célia Florimond
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Nicolas Landrein
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Keni Vidilaseris
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Marie Eggenspieler
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Johannes Lesigang
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Gang Dong
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
| | - Derrick Roy Robinson
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
| | - Mélanie Bonhivers
- University of Bordeaux, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
- CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
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Cavalier-Smith T. Euglenoid pellicle morphogenesis and evolution in light of comparative ultrastructure and trypanosomatid biology: Semi-conservative microtubule/strip duplication, strip shaping and transformation. Eur J Protistol 2017; 61:137-179. [DOI: 10.1016/j.ejop.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 08/19/2017] [Accepted: 09/05/2017] [Indexed: 11/27/2022]
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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] [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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Cooper C, Thompson RCA, Botero A, Kristancic A, Peacock C, Kirilak Y, Clode PL. A comparative molecular and 3-dimensional structural investigation into cross-continental and novel avian Trypanosoma spp. in Australia. Parasit Vectors 2017; 10:234. [PMID: 28499405 PMCID: PMC5427604 DOI: 10.1186/s13071-017-2173-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/03/2017] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Molecular and structural information on avian Trypanosoma spp. throughout Australia is limited despite their intrinsic value in understanding trypanosomatid evolution, diversity, and structural biology. In Western Australia tissue samples (n = 429) extracted from 93 birds in 25 bird species were screened using generic PCR primers to investigate the diversity of Trypanosoma spp. To investigate avian trypanosome structural biology the first 3-dimensional ultrastructural models of a Trypanosoma spp. (Trypanosoma sp. AAT) isolated from a bird (currawong, Strepera spp.) were generated using focussed ion beam milling combined with scanning electron microscopy (FIB-SEM). RESULTS Here, we confirm four intercontinental species of avian trypanosomes in native Australian birds, and identify a new avian Trypanosoma. Trypanosome infection was identified in 18 birds from 13 different bird species (19%). A single new genotype was isolated and found to be closely related to T. culicavium (Trypanosoma sp. CC2016 B002). Other Trypanosoma spp. identified include T. avium, T. culicavium, T. thomasbancrofti, Trypanosoma sp. TL.AQ.22, Trypanosoma sp. AAT, and an uncharacterised Trypanosoma sp. (group C-III sensu Zidková et al. (Infect Genet Evol 12:102-112, 2012)), all previously identified in Australia or other continents. Serially-sectioning Trypanosoma sp. AAT epimastigotes using FIB-SEM revealed the disc-shaped kinetoplast pocket attached perpendicular to the branching mitochondrion. Additionally, the universal minicircle sequence within the kinetoplast DNA and the associated binding protein were determined in Trypanosoma sp. AAT. CONCLUSIONS These results indicate that bird trypanosomes are relatively conserved across continents, while being locally diverse, which supports the hypothesis that bird trypanosomes exist as fewer species than described in the literature. Evidence exists that avian Trypanosoma spp. are infecting mammals and could be transmitted by haemadipsid leeches. Trypanosoma sp. AAT is most likely a separate species currently found only in Australia and the first 3-dimentional ultrastructural analysis of an avian trypanosome provides interesting information on their morphology and organelle arrangement.
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Affiliation(s)
- Crystal Cooper
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
| | - R. C. Andrew Thompson
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Adriana Botero
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Amanda Kristancic
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150 Australia
| | - Christopher Peacock
- Marshall Centre, School of Pathology and Laboratory and Medical Sciences, University of Western Australia, Crawley, WA 6009 Australia
- Telethon Kids Institute, 100 Roberts Rd, Subiaco, WA 6008 Australia
| | - Yaowanuj Kirilak
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
| | - Peta L. Clode
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, WA 6009 Australia
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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: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [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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Sullenberger C, Piqué D, Ogata Y, Mensa-Wilmot K. AEE788 Inhibits Basal Body Assembly and Blocks DNA Replication in the African Trypanosome. Mol Pharmacol 2017; 91:482-498. [PMID: 28246189 PMCID: PMC5399642 DOI: 10.1124/mol.116.106906] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 02/17/2017] [Indexed: 12/15/2022] Open
Abstract
Trypanosoma brucei causes human African trypanosomiasis (HAT). The pyrrolopyrimidine AEE788 (a hit for anti-HAT drug discovery) associates with three trypanosome protein kinases. Herein we delineate the effects of AEE788 on T. brucei using chemical biology strategies. AEE788 treatment inhibits DNA replication in the kinetoplast (mitochondrial nucleoid) and nucleus. In addition, AEE788 blocks duplication of the basal body and the bilobe without affecting mitosis. Thus, AEE788 prevents entry into the S-phase of the cell division cycle. To study the kinetics of early events in trypanosome division, we employed an "AEE788 block and release" protocol to stage entry into the S-phase. A time-course of DNA synthesis (nuclear and kinetoplast DNA), duplication of organelles (basal body, bilobe, kinetoplast, nucleus), and cytokinesis was obtained. Unexpected findings include the following: 1) basal body and bilobe duplication are concurrent; 2) maturation of probasal bodies, marked by TbRP2 recruitment, is coupled with nascent basal body assembly, monitored by localization of TbSAS6 at newly forming basal bodies; and 3) kinetoplast division is observed in G2 after completion of nuclear DNA synthesis. Prolonged exposure of trypanosomes to AEE788 inhibited transferrin endocytosis, altered cell morphology, and decreased cell viability. To discover putative effectors for the pleiotropic effects of AEE788, proteome-wide changes in protein phosphorylation induced by the drug were determined. Putative effectors include an SR protein kinase, bilobe proteins, TbSAS4, TbRP2, and BILBO-1. Loss of function of one or more of these effectors can, from published literature, explain the polypharmacology of AEE788 on trypanosome biology.
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Affiliation(s)
- Catherine Sullenberger
- Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia (C.S., D.P., K.M.-W.); and the Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington (Y.O.)
| | - Daniel Piqué
- Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia (C.S., D.P., K.M.-W.); and the Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington (Y.O.)
| | - Yuko Ogata
- Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia (C.S., D.P., K.M.-W.); and the Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington (Y.O.)
| | - Kojo Mensa-Wilmot
- Department of Cellular Biology, and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia (C.S., D.P., K.M.-W.); and the Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington (Y.O.)
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Proximity Interactions among Basal Body Components in Trypanosoma brucei Identify Novel Regulators of Basal Body Biogenesis and Inheritance. mBio 2017; 8:mBio.02120-16. [PMID: 28049148 PMCID: PMC5210500 DOI: 10.1128/mbio.02120-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The basal body shares similar architecture with centrioles in animals and is involved in nucleating flagellar axonemal microtubules in flagellated eukaryotes. The early-branching Trypanosoma brucei possesses a motile flagellum nucleated from the basal body that consists of a mature basal body and an adjacent pro-basal body. Little is known about the basal body proteome and its roles in basal body biogenesis and flagellar axoneme assembly in T. brucei. Here, we report the identification of 14 conserved centriole/basal body protein homologs and 25 trypanosome-specific basal body proteins. These proteins localize to distinct subdomains of the basal body, and several of them form a ring-like structure surrounding the basal body barrel. Functional characterization of representative basal body proteins revealed distinct roles in basal body duplication/separation and flagellar axoneme assembly. Overall, this work identified novel proteins required for basal body duplication and separation and uncovered new functions of conserved basal body proteins in basal body duplication and separation, highlighting an unusual mechanism of basal body biogenesis and inheritance in this early divergent eukaryote. The basal body in the early-branching protozoan Trypanosoma brucei nucleates flagellum assembly and also regulates organelle segregation, cell morphogenesis, and cell division. However, the molecular composition and the assembly process of the basal body remain poorly understood. Here, we identify 14 conserved basal body proteins and 25 trypanosome-specific basal body proteins via bioinformatics, localization-based screening, and proximity-dependent biotin identification. We further localized these proteins to distinct subdomains of the basal body by using fluorescence microscopy and superresolution microscopy, discovered novel regulators of basal body duplication and separation, and uncovered new functions of conserved basal body proteins in basal body duplication and separation. This work lays the foundation for dissecting the mechanisms underlying basal body biogenesis and inheritance in T. brucei.
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40
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Two flagellar BAR domain proteins in Trypanosoma brucei with stage-specific regulation. Sci Rep 2016; 6:35826. [PMID: 27779220 PMCID: PMC5078803 DOI: 10.1038/srep35826] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 10/03/2016] [Indexed: 01/08/2023] Open
Abstract
Trypanosomes are masters of adaptation to different host environments during their complex life cycle. Large-scale proteomic approaches provide information on changes at the cellular level, and in a systematic way. However, detailed work on single components is necessary to understand the adaptation mechanisms on a molecular level. Here, we have performed a detailed characterization of a bloodstream form (BSF) stage-specific putative flagellar host adaptation factor Tb927.11.2400, identified previously in a SILAC-based comparative proteome study. Tb927.11.2400 shares 38% amino acid identity with TbFlabarin (Tb927.11.2410), a procyclic form (PCF) stage-specific flagellar BAR domain protein. We named Tb927.11.2400 TbFlabarin-like (TbFlabarinL), and demonstrate that it originates from a gene duplication event, which occurred in the African trypanosomes. TbFlabarinL is not essential for the growth of the parasites under cell culture conditions and it is dispensable for developmental differentiation from BSF to the PCF in vitro. We generated TbFlabarinL-specific antibodies, and showed that it localizes in the flagellum. Co-immunoprecipitation experiments together with a biochemical cell fractionation suggest a dual association of TbFlabarinL with the flagellar membrane and the components of the paraflagellar rod.
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41
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Cooper C, Clode PL, Peacock C, Thompson RCA. Host-Parasite Relationships and Life Histories of Trypanosomes in Australia. ADVANCES IN PARASITOLOGY 2016; 97:47-109. [PMID: 28325373 DOI: 10.1016/bs.apar.2016.06.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Trypanosomes constitute a group of flagellate protozoan parasites responsible for a number of important, yet neglected, diseases in both humans and livestock. The most significantly studied include the causative agents of African sleeping sickness (Trypanosoma brucei) and Chagas disease (Trypanosoma cruzi) in humans. Much of our knowledge about trypanosome host-parasite relationships and life histories has come from these two human pathogens. Recent investigations into the diversity and life histories of wildlife trypanosomes in Australia highlight that there exists a great degree of biological and behavioural variation within and between trypanosomes. In addition, the genetic relationships between some Australian trypanosomes show that they are unexpectedly more closely related to species outside Australia than within it. These findings have led to a growing focus on the importance of understanding parasites occurring naturally in wildlife to (1) better document parasite biodiversity, (2) determine evolutionary relationships and degree of host specificity, (3) understand host-parasite interactions and the role of parasites in the natural ecosystem and (4) identify biosecurity issues of emerging disease in both wildlife and human populations. Here we review what is known about the diversity, life histories, host-parasite interactions and evolutionary relationships of trypanosomes in Australian wildlife. In this context, we focus upon the genetic proximity of key Australian species to the pathogenic T. cruzi and discuss similarities in their biology and behaviour that present a potential risk of human disease transmission by Australian vectors and wildlife.
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Affiliation(s)
- C Cooper
- The University of Western Australia, Crawley, WA, Australia
| | - P L Clode
- The University of Western Australia, Crawley, WA, Australia
| | - C Peacock
- The University of Western Australia, Crawley, WA, Australia; Telethon Kids Institute, Subiaco, WA, Australia
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TAC102 Is a Novel Component of the Mitochondrial Genome Segregation Machinery in Trypanosomes. PLoS Pathog 2016; 12:e1005586. [PMID: 27168148 PMCID: PMC4864229 DOI: 10.1371/journal.ppat.1005586] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/30/2016] [Indexed: 11/19/2022] Open
Abstract
Trypanosomes show an intriguing organization of their mitochondrial DNA into a catenated network, the kinetoplast DNA (kDNA). While more than 30 proteins involved in kDNA replication have been described, only few components of kDNA segregation machinery are currently known. Electron microscopy studies identified a high-order structure, the tripartite attachment complex (TAC), linking the basal body of the flagellum via the mitochondrial membranes to the kDNA. Here we describe TAC102, a novel core component of the TAC, which is essential for proper kDNA segregation during cell division. Loss of TAC102 leads to mitochondrial genome missegregation but has no impact on proper organelle biogenesis and segregation. The protein is present throughout the cell cycle and is assembled into the newly developing TAC only after the pro-basal body has matured indicating a hierarchy in the assembly process. Furthermore, we provide evidence that the TAC is replicated de novo rather than using a semi-conservative mechanism. Lastly, we demonstrate that TAC102 lacks an N-terminal mitochondrial targeting sequence and requires sequences in the C-terminal part of the protein for its proper localization. Proper segregation of the mitochondrial genome during cell division is a prerequisite of healthy eukaryotic cells. However, the mechanism underlying the segregation process is only poorly understood. We use the single celled parasite Trypanosoma brucei, which, unlike most model organisms, harbors a single large mitochondrion with a single mitochondrial genome, also called kinetoplast DNA (kDNA), to study this question. In trypanosomes, kDNA replication and segregation are tightly integrated into the cell cycle and thus can be studied alongside cell cycle markers. Furthermore, previous studies using electron microscopy have characterized the tripartite attachment complex (TAC) as a structural element of the mitochondrial genome segregation machinery. Here, we characterize TAC102, a novel trypanosome protein localized to the TAC. The protein is essential for proper kDNA segregation and cell growth. We analyze the presence of this protein using super resolution microscopy and show that TAC102 is a mitochondrial protein localized between the kDNA and the basal body of the cell’s flagellum. In addition, we characterize different parts of the protein and show that the C-terminus of TAC102 is important for its proper localization. The data and resources presented will allow a more detailed characterization of the dynamics and hierarchy of the TAC in the future and might open new avenues for drug discovery targeting this structure.
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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] [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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Vaughan S, Gull K. Basal body structure and cell cycle-dependent biogenesis in Trypanosoma brucei. Cilia 2016; 5:5. [PMID: 26862392 PMCID: PMC4746817 DOI: 10.1186/s13630-016-0023-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/19/2016] [Indexed: 11/10/2022] Open
Abstract
Basal bodies are microtubule-based organelles that assemble cilia and flagella, which are critical for motility and sensory functions in all major eukaryotic lineages. The core structure of the basal body is highly conserved, but there is variability in biogenesis and additional functions that are organism and cell type specific. Work carried out in the protozoan parasite Trypanosoma brucei has arguably produced one of the most detailed dissections of basal body structure and biogenesis within the context of the flagellar pocket and associated organelles. In this review, we provide a detailed overview of the basic basal body structure in T. brucei along with the accessory structures and show how basal body movements during the basal body duplication cycle orchestrate cell and organelle morphogenesis. With this in-depth three-dimensional knowledge, identification of many basal body genes coupled with excellent genetic tools makes it an attractive model organism to study basal body biogenesis and maintenance.
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Affiliation(s)
- Sue Vaughan
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford, OX3 0BP UK
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE UK
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45
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Höög JL, Lacomble S, Bouchet-Marquis C, Briggs L, Park K, Hoenger A, Gull K. 3D Architecture of the Trypanosoma brucei Flagella Connector, a Mobile Transmembrane Junction. PLoS Negl Trop Dis 2016; 10:e0004312. [PMID: 26820516 PMCID: PMC4731218 DOI: 10.1371/journal.pntd.0004312] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/29/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Cellular junctions are crucial for the formation of multicellular organisms, where they anchor cells to each other and/or supportive tissue and enable cell-to-cell communication. Some unicellular organisms, such as the parasitic protist Trypanosoma brucei, also have complex cellular junctions. The flagella connector (FC) is a three-layered transmembrane junction that moves with the growing tip of a new flagellum and attaches it to the side of the old flagellum. The FC moves via an unknown molecular mechanism, independent of new flagellum growth. Here we describe the detailed 3D architecture of the FC suggesting explanations for how it functions and its mechanism of motility. METHODOLOGY/PRINCIPAL FINDINGS We have used a combination of electron tomography and cryo-electron tomography to reveal the 3D architecture of the FC. Cryo-electron tomography revealed layers of repetitive filamentous electron densities between the two flagella in the interstitial zone. Though the FC does not change in length and width during the growth of the new flagellum, the interstitial zone thickness decreases as the FC matures. This investigation also shows interactions between the FC layers and the axonemes of the new and old flagellum, sufficiently strong to displace the axoneme in the old flagellum. We describe a novel filament, the flagella connector fibre, found between the FC and the axoneme in the old flagellum. CONCLUSIONS/SIGNIFICANCE The FC is similar to other cellular junctions in that filamentous proteins bridge the extracellular space and are anchored to underlying cytoskeletal structures; however, it is built between different portions of the same cell and is unique because of its intrinsic motility. The detailed description of its structure will be an important tool to use in attributing structure / function relationships as its molecular components are discovered in the future. The FC is involved in the inheritance of cell shape, which is important for the life cycle of this human parasite.
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Affiliation(s)
- Johanna L. Höög
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
- The Boulder Laboratory for 3D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
- * E-mail: ,
| | - Sylvain Lacomble
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | | | - Laura Briggs
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Kristin Park
- The Boulder Laboratory for 3D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Andreas Hoenger
- The Boulder Laboratory for 3D Electron Microscopy of Cells, Department of MCD Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Keith Gull
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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46
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Wheeler RJ, Sunter JD, Gull K. Flagellar pocket restructuring through the Leishmania life cycle involves a discrete flagellum attachment zone. J Cell Sci 2016; 129:854-67. [PMID: 26746239 PMCID: PMC4760377 DOI: 10.1242/jcs.183152] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 12/29/2015] [Indexed: 01/10/2023] Open
Abstract
Leishmania promastigote parasites have a flagellum, which protrudes from the flagellar pocket at the cell anterior, yet, surprisingly, have homologs of many flagellum attachment zone (FAZ) proteins – proteins used in the related Trypanosoma species to laterally attach the flagellum to the cell body from the flagellar pocket to the cell posterior. Here, we use seven Leishmania mexicana cell lines that expressed eYFP fusions of FAZ protein homologs to show that the Leishmania flagellar pocket includes a FAZ structure. Electron tomography revealed a precisely defined 3D organisation for both the flagellar pocket and FAZ, with striking similarities to those of Trypanosoma brucei. Expression of two T. brucei FAZ proteins in L. mexicana showed that T. brucei FAZ proteins can assemble into the Leishmania FAZ structure. Leishmania therefore have a previously unrecognised FAZ structure, which we show undergoes major structural reorganisation in the transition from the promastigote (sandfly vector) to amastigote (in mammalian macrophages). Morphogenesis of the Leishmania flagellar pocket, a structure important for pathogenicity, is therefore intimately associated with a FAZ; a finding with implications for understanding shape changes involving component modules during evolution. Summary:Leishmania parasites have a highly structured flagellar pocket, including a structure homologous to the Trypanosoma brucei flagellum attachment zone, which undergoes structural adaptations in different life cycle stages.
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Affiliation(s)
- Richard J Wheeler
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, Dresden 01307, Germany Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | - Jack D Sunter
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
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Alcantara CDL, Vidal JC, de Souza W, Cunha-e-Silva NL. The cytostome-cytopharynx complex of Trypanosoma cruzi epimastigotes disassembles during cell division. J Cell Sci 2016; 130:164-176. [DOI: 10.1242/jcs.187419] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 06/27/2016] [Indexed: 01/11/2023] Open
Abstract
The cytostome-cytopharynx complex is the main site for endocytosis in epimastigotes of Trypanosoma cruzi. It consists of an opening at the plasma membrane surface – the cytostome - followed by a membrane invagination - the cytopharynx. In G1-S cells, this structure is associated with two specific sets of microtubules - a quartet and a triplet. Here, we used electron microscopy and electron tomography to build 3D models of the complex at different stages of the cell cycle. The cytostome-cytopharynx is absent in late G2 and M phase cells, while early G2 cells have either a short cytopharynx or no visible complex, with numerous vesicles aligned to the cytostome-cytopharynx microtubules. The microtubule quartet remains visible throughout cell division (albeit in a shorter form), and is duplicated during G2/M. In contrast, the microtubule triplet is absent during late G2/M. Cells in cytokinesis have an invagination of the flagellar pocket membrane likely to represent early stages in cytostome-cytopharynx assembly. Cells in late cytokinesis have two fully developed cytostome-cytopharynx complexes. Our data suggest that the microtubule quartet serves as a guide for new cytostome-cytopharynx assembly.
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Affiliation(s)
- Carolina de L. Alcantara
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro, Brazil
| | - Juliana C. Vidal
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro, Brazil
| | - Wanderley de Souza
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro, Brazil
| | - Narcisa L. Cunha-e-Silva
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro, Brazil
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Morriswood B. Form, Fabric, and Function of a Flagellum-Associated Cytoskeletal Structure. Cells 2015; 4:726-47. [PMID: 26540076 PMCID: PMC4695855 DOI: 10.3390/cells4040726] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 10/27/2015] [Accepted: 10/29/2015] [Indexed: 01/01/2023] Open
Abstract
Trypanosoma brucei is a uniflagellated protist and the causative agent of African trypanosomiasis, a neglected tropical disease. The single flagellum of T. brucei is essential to a number of cellular processes such as motility, and has been a longstanding focus of scientific enquiry. A number of cytoskeletal structures are associated with the flagellum in T. brucei, and one such structure—a multiprotein complex containing the repeat motif protein TbMORN1—is the focus of this review. The TbMORN1-containing complex, which was discovered less than ten years ago, is essential for the viability of the mammalian-infective form of T. brucei. The complex has an unusual asymmetric morphology, and is coiled around the flagellum to form a hook shape. Proteomic analysis using the proximity-dependent biotin identification (BioID) technique has elucidated a number of its components. Recent work has uncovered a role for TbMORN1 in facilitating protein entry into the cell, thus providing a link between the cytoskeleton and the endomembrane system. This review summarises the extant data on the complex, highlights the outstanding questions for future enquiry, and provides speculation as to its possible role in a size-exclusion mechanism for regulating protein entry. The review additionally clarifies the nomenclature associated with this topic, and proposes the adoption of the term “hook complex” to replace the former name “bilobe” to describe the complex.
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Affiliation(s)
- Brooke Morriswood
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, Am Hubland, D-97074, Würzburg, Germany.
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49
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Sphingosine Kinase Regulates Microtubule Dynamics and Organelle Positioning Necessary for Proper G1/S Cell Cycle Transition in Trypanosoma brucei. mBio 2015; 6:e01291-15. [PMID: 26443455 PMCID: PMC4611037 DOI: 10.1128/mbio.01291-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
UNLABELLED Sphingolipids are important constituents of cell membranes and also serve as mediators of cell signaling and cell recognition. Sphingolipid metabolites such as sphingosine-1-phosphate and ceramide regulate signaling cascades involved in cell proliferation and differentiation, autophagy, inflammation, and apoptosis. Little is known about how sphingolipids and their metabolites function in single-celled eukaryotes. In the present study, we investigated the role of sphingosine kinase (SPHK) in the biology of the protozoan parasite Trypanosoma brucei, the agent of African sleeping sickness. T. brucei SPHK (TbSPHK) is constitutively but differentially expressed during the life cycle of T. brucei. Depletion of TbSPHK in procyclic-form T. brucei causes impaired growth and attenuation in the G1/S phase of the cell cycle. TbSPHK-depleted cells also develop organelle positioning defects and an accumulation of tyrosinated α-tubulin at the elongated posterior end of the cell, known as the "nozzle" phenotype, caused by other molecular perturbations in this organism. Our studies indicate that TbSPHK is involved in G1-to-S cell cycle progression, organelle positioning, and maintenance of cell morphology. Cytotoxicity assays using TbSPHK inhibitors revealed a favorable therapeutic index between T. brucei and human cells, suggesting TbSPHK to be a novel drug target. IMPORTANCE Trypanosoma brucei is a single-celled parasite that is transmitted between humans and other animals by the tsetse fly. T. brucei is endemic in sub-Saharan Africa, where over 70 million people and countless livestock are at risk of developing T. brucei infection, called African sleeping sickness, resulting in economic losses of ~$35 million from the loss of cattle alone. New drugs for this infection are sorely needed and scientists are trying to identify essential enzymes in the parasite that can be targets for new therapies. One possible enzyme target is sphingosine kinase, an enzyme involved in the synthesis of lipids important for cell surface integrity and regulation of cell functions. In this study, we found that sphingosine kinase is essential for normal growth and structure of the parasite, raising the possibility that it could be a good target for new chemotherapy for sleeping sickness.
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50
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McAllaster MR, Ikeda KN, Lozano-Núñez A, Anrather D, Unterwurzacher V, Gossenreiter T, Perry JA, Crickley R, Mercadante CJ, Vaughan S, de Graffenried CL. Proteomic identification of novel cytoskeletal proteins associated with TbPLK, an essential regulator of cell morphogenesis in Trypanosoma brucei. Mol Biol Cell 2015; 26:3013-29. [PMID: 26133384 PMCID: PMC4551316 DOI: 10.1091/mbc.e15-04-0219] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 01/06/2023] Open
Abstract
Trypanosoma brucei is the causative agent of African sleeping sickness, a devastating disease endemic to sub-Saharan Africa with few effective treatment options. The parasite is highly polarized, including a single flagellum that is nucleated at the posterior of the cell and adhered along the cell surface. These features are essential and must be transmitted to the daughter cells during division. Recently we identified the T. brucei homologue of polo-like kinase (TbPLK) as an essential morphogenic regulator. In the present work, we conduct proteomic screens to identify potential TbPLK binding partners and substrates to better understand the molecular mechanisms of kinase function. These screens identify a cohort of proteins, most of which are completely uncharacterized, which localize to key cytoskeletal organelles involved in establishing cell morphology, including the flagella connector, flagellum attachment zone, and bilobe structure. Depletion of these proteins causes substantial changes in cell division, including mispositioning of the kinetoplast, loss of flagellar connection, and prevention of cytokinesis. The proteins identified in these screens provide the foundation for establishing the molecular networks through which TbPLK directs cell morphogenesis in T. brucei.
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Affiliation(s)
- Michael R McAllaster
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
| | - Kyojiro N Ikeda
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria
| | - Ana Lozano-Núñez
- Max F. Perutz Laboratories, Center for Molecular Biology, University of Vienna, 1030 Vienna, Austria
| | - Dorothea Anrather
- Max F. Perutz Laboratories, Mass Spectrometry Facility, University of Vienna, 1030 Vienna, Austria
| | - Verena Unterwurzacher
- Max F. Perutz Laboratories, Mass Spectrometry Facility, University of Vienna, 1030 Vienna, Austria
| | - Thomas Gossenreiter
- Max F. Perutz Laboratories, Mass Spectrometry Facility, University of Vienna, 1030 Vienna, Austria
| | - Jenna A Perry
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
| | - Robbie Crickley
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Courtney J Mercadante
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912
| | - Sue Vaughan
- Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
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