1
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Gray S, Fort C, Wheeler RJ. Intraflagellar transport speed is sensitive to genetic and mechanical perturbations to flagellar beating. J Cell Biol 2024; 223:e202401154. [PMID: 38829962 PMCID: PMC11148470 DOI: 10.1083/jcb.202401154] [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: 01/31/2024] [Revised: 05/01/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024] Open
Abstract
Two sets of motor proteins underpin motile cilia/flagella function. The axoneme-associated inner and outer dynein arms drive sliding of adjacent axoneme microtubule doublets to periodically bend the flagellum for beating, while intraflagellar transport (IFT) kinesins and dyneins carry IFT trains bidirectionally along the axoneme. Despite assembling motile cilia and flagella, IFT train speeds have only previously been quantified in immobilized flagella-mechanical immobilization or genetic paralysis. This has limited investigation of the interaction between IFT and flagellar beating. Here, in uniflagellate Leishmania parasites, we use high-frequency, dual-color fluorescence microscopy to visualize IFT train movement in beating flagella. We discovered that adhesion of flagella to a microscope slide is detrimental, reducing IFT train speed and increasing train stalling. In flagella free to move, IFT train speed is not strongly dependent on flagella beat type; however, permanent disruption of flagella beating by deletion of genes necessary for formation or regulation of beating showed an inverse correlation of beat frequency and IFT train speed.
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Affiliation(s)
- Sophie Gray
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Cecile Fort
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
| | - Richard John Wheeler
- Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, University of Oxford, Oxford, UK
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2
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De Niz M, Frachon E, Gobaa S, Bastin P. Spatial confinement of Trypanosoma brucei in microfluidic traps provides a new tool to study free swimming parasites. PLoS One 2023; 18:e0296257. [PMID: 38134042 PMCID: PMC10745224 DOI: 10.1371/journal.pone.0296257] [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: 07/04/2023] [Accepted: 12/09/2023] [Indexed: 12/24/2023] Open
Abstract
Trypanosoma brucei is the causative agent of African trypanosomiasis and is transmitted by the tsetse fly (Glossina spp.). All stages of this extracellular parasite possess a single flagellum that is attached to the cell body and confers a high degree of motility. While several stages are amenable to culture in vitro, longitudinal high-resolution imaging of free-swimming parasites has been challenging, mostly due to the rapid flagellar beating that constantly twists the cell body. Here, using microfabrication, we generated various microfluidic devices with traps of different geometrical properties. Investigation of trap topology allowed us to define the one most suitable for single T. brucei confinement within the field of view of an inverted microscope while allowing the parasite to remain motile. Chips populated with V-shaped traps allowed us to investigate various phenomena in cultured procyclic stage wild-type parasites, and to compare them with parasites whose motility was altered upon knockdown of a paraflagellar rod component. Among the properties that we investigated were trap invasion, parasite motility, and the visualization of organelles labelled with fluorescent dyes. We envisage that this tool we have named "Tryp-Chip" will be a useful tool for the scientific community, as it could allow high-throughput, high-temporal and high-spatial resolution imaging of free-swimming T. brucei parasites.
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Affiliation(s)
- Mariana De Niz
- Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, INSERM U1201, Paris, France
| | - Emmanuel Frachon
- Institut Pasteur, Université de Paris, Biomaterials and Microfluidics Core Facility, Paris, France
| | - Samy Gobaa
- Institut Pasteur, Université de Paris, Biomaterials and Microfluidics Core Facility, Paris, France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, INSERM U1201, Paris, France
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3
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Dacheux D, Martinez G, Broster Reix CE, Beurois J, Lores P, Tounkara M, Dupuy JW, Robinson DR, Loeuillet C, Lambert E, Wehbe Z, Escoffier J, Amiri-Yekta A, Daneshipour A, Hosseini SH, Zouari R, Mustapha SFB, Halouani L, Jiang X, Shen Y, Liu C, Thierry-Mieg N, Septier A, Bidart M, Satre V, Cazin C, Kherraf ZE, Arnoult C, Ray PF, Toure A, Bonhivers M, Coutton C. Novel axonemal protein ZMYND12 interacts with TTC29 and DNAH1, and is required for male fertility and flagellum function. eLife 2023; 12:RP87698. [PMID: 37934199 PMCID: PMC10629824 DOI: 10.7554/elife.87698] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Male infertility is common and complex, presenting a wide range of heterogeneous phenotypes. Although about 50% of cases are estimated to have a genetic component, the underlying cause often remains undetermined. Here, from whole-exome sequencing on samples from 168 infertile men with asthenoteratozoospermia due to severe sperm flagellum, we identified homozygous ZMYND12 variants in four unrelated patients. In sperm cells from these individuals, immunofluorescence revealed altered localization of DNAH1, DNALI1, WDR66, and TTC29. Axonemal localization of ZMYND12 ortholog TbTAX-1 was confirmed using the Trypanosoma brucei model. RNAi knock-down of TbTAX-1 dramatically affected flagellar motility, with a phenotype similar to the sperm from men bearing homozygous ZMYND12 variants. Co-immunoprecipitation and ultrastructure expansion microscopy in T. brucei revealed TbTAX-1 to form a complex with TTC29. Comparative proteomics with samples from Trypanosoma and Ttc29 KO mice identified a third member of this complex: DNAH1. The data presented revealed that ZMYND12 is part of the same axonemal complex as TTC29 and DNAH1, which is critical for flagellum function and assembly in humans, and Trypanosoma. ZMYND12 is thus a new asthenoteratozoospermia-associated gene, bi-allelic variants of which cause severe flagellum malformations and primary male infertility.
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Affiliation(s)
- Denis Dacheux
- University of Bordeaux, CNRSBordeauxFrance
- Bordeaux INP, Microbiologie Fondamentale et PathogénicitéBordeauxFrance
| | | | | | - Julie Beurois
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Patrick Lores
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris CiteParisFrance
| | | | | | | | - Corinne Loeuillet
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Emeline Lambert
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Zeina Wehbe
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Jessica Escoffier
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Amir Amiri-Yekta
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECRTehranIslamic Republic of Iran
| | - Abbas Daneshipour
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECRTehranIslamic Republic of Iran
| | - Seyedeh-Hanieh Hosseini
- Department of Andrology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECRTehranIslamic Republic of Iran
| | - Raoudha Zouari
- Polyclinique les Jasmins, Centre d'Aide Médicale à la Procréation, Centre Urbain NordTunisTunisia
| | | | - Lazhar Halouani
- Polyclinique les Jasmins, Centre d'Aide Médicale à la Procréation, Centre Urbain NordTunisTunisia
| | - Xiaohui Jiang
- Human Sperm Bank, West China Second University Hospital of Sichuan UniversitySichuanChina
- NHC Key Laboratory of Chronobiology, Sichuan UniversitySichuanChina
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of EducationSichuanChina
| | - Ying Shen
- NHC Key Laboratory of Chronobiology, Sichuan UniversitySichuanChina
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of EducationSichuanChina
| | - Chunyu Liu
- Obstetrics and Gynecology Hospital, Fudan UniversityFudanChina
| | | | | | - Marie Bidart
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
- CHU Grenoble Alpes, Laboratoire de Génétique Moléculaire: Maladies Héréditaires et OncologieGrenobleFrance
| | - Véronique Satre
- CHU Grenoble-Alpes, UM de Génétique ChromosomiqueGrenobleFrance
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Caroline Cazin
- CHU Grenoble-Alpes, UM de Génétique ChromosomiqueGrenobleFrance
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
- CHU de Grenoble, UM GI-DPIGrenobleFrance
| | - Zine Eddine Kherraf
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
- CHU de Grenoble, UM GI-DPIGrenobleFrance
| | - Christophe Arnoult
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
| | - Pierre F Ray
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
- CHU de Grenoble, UM GI-DPIGrenobleFrance
| | - Aminata Toure
- Institute for Advanced Biosciences, INSERM U 1209, CNRS UMR 5309, Université Grenoble Alpes, Team Physiology and Pathophysiology of Sperm cellsGrenobleFrance
| | | | - Charles Coutton
- Institute for Advanced Biosciences, INSERM U1209, CNRS UMR 5309, Université Grenoble Alpes, Team Genetics Epigenetics and Therapies of InfertilityGrenobleFrance
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4
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Godar S, Oristian J, Hinsch V, Wentworth K, Lopez E, Amlashi P, Enverso G, Markley S, Alper JD. Light chain 2 is a Tctex-type related axonemal dynein light chain that regulates directional ciliary motility in Trypanosoma brucei. PLoS Pathog 2022; 18:e1009984. [PMID: 36155669 PMCID: PMC9536576 DOI: 10.1371/journal.ppat.1009984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/06/2022] [Accepted: 08/26/2022] [Indexed: 01/04/2023] Open
Abstract
Flagellar motility is essential for the cell morphology, viability, and virulence of pathogenic kinetoplastids. Trypanosoma brucei flagella beat with a bending wave that propagates from the flagellum's tip to its base, rather than base-to-tip as in other eukaryotes. Thousands of dynein motor proteins coordinate their activity to drive ciliary bending wave propagation. Dynein-associated light and intermediate chains regulate the biophysical mechanisms of axonemal dynein. Tctex-type outer arm dynein light chain 2 (LC2) regulates flagellar bending wave propagation direction, amplitude, and frequency in Chlamydomonas reinhardtii. However, the role of Tctex-type light chains in regulating T. brucei motility is unknown. Here, we used a combination of bioinformatics, in-situ molecular tagging, and immunofluorescence microscopy to identify a Tctex-type light chain in the procyclic form of T. brucei (TbLC2). We knocked down TbLC2 expression using RNAi in both wild-type and FLAM3, a flagellar attachment zone protein, knockdown cells and quantified TbLC2's effects on trypanosome cell biology and biophysics. We found that TbLC2 knockdown reduced the directional persistence of trypanosome cell swimming, induced an asymmetric ciliary bending waveform, modulated the bias between the base-to-tip and tip-to-base beating modes, and increased the beating frequency. Together, our findings are consistent with a model of TbLC2 as a down-regulator of axonemal dynein activity that stabilizes the forward tip-to-base beating ciliary waveform characteristic of trypanosome cells. Our work sheds light on axonemal dynein regulation mechanisms that contribute to pathogenic kinetoplastids' unique tip-to-base ciliary beating nature and how those mechanisms underlie dynein-driven ciliary motility more generally.
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Affiliation(s)
- Subash Godar
- Department of Physics and Astronomy, College of Science, Clemson University, Clemson, South Carolina, United States of America
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
| | - James Oristian
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Genetics and Biochemistry, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Valerie Hinsch
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Genetics and Biochemistry, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Katherine Wentworth
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Biological Sciences, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Ethan Lopez
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Genetics and Biochemistry, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Parastoo Amlashi
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Biological Sciences, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Gerald Enverso
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Biological Sciences, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Samantha Markley
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Biological Sciences, College of Science, Clemson University, Clemson, South Carolina, United States of America
| | - Joshua Daniel Alper
- Department of Physics and Astronomy, College of Science, Clemson University, Clemson, South Carolina, United States of America
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, United States of America
- Department of Biological Sciences, College of Science, Clemson University, Clemson, South Carolina, United States of America
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5
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Sáez Conde J, Dean S. Structure, function and druggability of the African trypanosome flagellum. J Cell Physiol 2022; 237:2654-2667. [PMID: 35616248 PMCID: PMC9323424 DOI: 10.1002/jcp.30778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 11/29/2022]
Abstract
African trypanosomes are early branching protists that cause human and animal diseases, termed trypanosomiases. They have been under intensive study for more than 100 years and have contributed significantly to our understanding of eukaryotic biology. The combination of conserved and parasite‐specific features mean that their flagellum has gained particular attention. Here, we discuss the different structural features of the flagellum and their role in transmission and virulence. We highlight the possibilities of targeting flagellar function to cure trypanosome infections and help in the fight to eliminate trypanosomiases.
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Affiliation(s)
- Julia Sáez Conde
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Samuel Dean
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK
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6
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Rao Q, Han L, Wang Y, Chai P, Kuo YW, Yang R, Hu F, Yang Y, Howard J, Zhang K. Structures of outer-arm dynein array on microtubule doublet reveal a motor coordination mechanism. Nat Struct Mol Biol 2021; 28:799-810. [PMID: 34556869 PMCID: PMC8500839 DOI: 10.1038/s41594-021-00656-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022]
Abstract
Thousands of outer-arm dyneins (OADs) are arrayed in the axoneme to drive a rhythmic ciliary beat. Coordination among multiple OADs is essential for generating mechanical forces to bend microtubule doublets (MTDs). Using electron microscopy, we determined high-resolution structures of Tetrahymena thermophila OAD arrays bound to MTDs in two different states. OAD preferentially binds to MTD protofilaments with a pattern resembling the native tracks for its distinct microtubule-binding domains. Upon MTD binding, free OADs are induced to adopt a stable parallel conformation, primed for array formation. Extensive tail-to-head (TTH) interactions between OADs are observed, which need to be broken for ATP turnover by the dynein motor. We propose that OADs in an array sequentially hydrolyze ATP to slide the MTDs. ATP hydrolysis in turn relaxes the TTH interfaces to effect free nucleotide cycles of downstream OADs. These findings lead to a model explaining how conformational changes in the axoneme produce coordinated action of dyneins.
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Affiliation(s)
- Qinhui Rao
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Long Han
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Yue Wang
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Pengxin Chai
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Yin-wei Kuo
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Renbin Yang
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Fangheng Hu
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Yuchen Yang
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Jonathon Howard
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
| | - Kai Zhang
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT USA
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7
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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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8
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Miller JC, Delzell SB, Concepción-Acevedo J, Boucher MJ, Klingbeil MM. A DNA polymerization-independent role for mitochondrial DNA polymerase I-like protein C in African trypanosomes. J Cell Sci 2020; 133:jcs.233072. [PMID: 32079654 DOI: 10.1242/jcs.233072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/10/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial DNA of Trypanosoma brucei and related parasites is a catenated network containing thousands of minicircles and tens of maxicircles, called kinetoplast DNA (kDNA). Replication of a single nucleoid requires at least three DNA polymerase I-like proteins (i.e. POLIB, POLIC and POLID), each showing discrete localizations near the kDNA during S phase. POLIB and POLID have roles in minicircle replication but the specific role of POLIC in kDNA maintenance is less clear. Here, we use an RNA interference (RNAi)-complementation system to dissect the functions of two distinct POLIC regions, i.e. the conserved family A DNA polymerase (POLA) domain and the uncharacterized N-terminal region (UCR). While RNAi complementation with wild-type POLIC restored kDNA content and cell cycle localization of kDNA, active site point mutations in the POLA domain impaired minicircle replication similar to that of POLIB and POLID depletions. Complementation with POLA domain alone abolished the formation of POLIC foci and partially rescued the RNAi phenotype. Furthermore, we provide evidence that the UCR is crucial in cell cycle-dependent protein localization and facilitates proper distribution of progeny networks. This is the first report of a DNA polymerase that impacts on mitochondrial nucleoid distribution.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Jonathan C Miller
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Stephanie B Delzell
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Jeniffer Concepción-Acevedo
- Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Michael J Boucher
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Michele M Klingbeil
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA .,Division of Foodborne,Waterborne, and Environmental Diseases, The Institute of Applied Life Sciences, University of Massachusetts, Amherst, MA 01003, USA
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9
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Zhang X, Hu H, Lun ZR, Li Z. Functional analyses of an axonemal inner-arm dynein complex in the bloodstream form of Trypanosoma brucei uncover its essential role in cytokinesis initiation. Mol Microbiol 2019; 112:1718-1730. [PMID: 31515877 DOI: 10.1111/mmi.14385] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2019] [Indexed: 01/26/2023]
Abstract
The flagellated eukaryote Trypanosoma brucei alternates between the insect vector and the mammalian host and proliferates through an unusual mode of cell division. Cell division requires flagellum motility-generated forces, but flagellum motility exerts distinct effects between different life cycle forms. Motility is required for the final cell abscission of the procyclic form in the insect vector, but is necessary for the initiation of cell division of the bloodstream form in the mammalian host. The underlying mechanisms remain elusive. Here we carried out functional analyses of a flagellar axonemal inner-arm dynein complex in the bloodstream form and investigated its mechanistic role in cytokinesis initiation. We showed that the axonemal inner-arm dynein heavy chain TbIAD5-1 and TbCentrin3 form a complex, localize to the flagellum, and are required for viability in the bloodstream form. We further demonstrated the interdependence between TbIAD5-1 and TbCentrin3 for maintenance of protein stability. Finally, we showed that depletion of TbIAD5-1 and TbCentrin3 arrested cytokinesis initiation and disrupted the localization of multiple cytokinesis initiation regulators. These findings identified the essential role of an axonemal inner-arm dynein complex in cell division, and provided molecular insights into the flagellum motility-mediated cytokinesis initiation in the bloodstream form of T. brucei.
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Affiliation(s)
- Xuan Zhang
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.,Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - Huiqing Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Zhao-Rong Lun
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, China
| | - 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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10
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Parasite motility is critical for virulence of African trypanosomes. Sci Rep 2018; 8:9122. [PMID: 29904094 PMCID: PMC6002391 DOI: 10.1038/s41598-018-27228-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/23/2018] [Indexed: 12/19/2022] Open
Abstract
African trypanosomes, Trypanosoma brucei spp., are lethal pathogens that cause substantial human suffering and limit economic development in some of the world's most impoverished regions. The name Trypanosoma ("auger cell") derives from the parasite's distinctive motility, which is driven by a single flagellum. However, despite decades of study, a requirement for trypanosome motility in mammalian host infection has not been established. LC1 is a conserved dynein subunit required for flagellar motility. Prior studies with a conditional RNAi-based LC1 mutant, RNAi-K/R, revealed that parasites with defective motility could infect mice. However, RNAi-K/R retained residual expression of wild-type LC1 and residual motility, thus precluding definitive interpretation. To overcome these limitations, here we generate constitutive mutants in which both LC1 alleles are replaced with mutant versions. These double knock-in mutants show reduced motility compared to RNAi-K/R and are viable in culture, but are unable to maintain bloodstream infection in mice. The virulence defect is independent of infection route but dependent on an intact host immune system. By comparing different mutants, we also reveal a critical dependence on the LC1 N-terminus for motility and virulence. Our findings demonstrate that trypanosome motility is critical for establishment and maintenance of bloodstream infection, implicating dynein-dependent flagellar motility as a potential drug target.
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Mutations in CFAP43 and CFAP44 cause male infertility and flagellum defects in Trypanosoma and human. Nat Commun 2018; 9:686. [PMID: 29449551 PMCID: PMC5814398 DOI: 10.1038/s41467-017-02792-7] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/28/2017] [Indexed: 11/09/2022] Open
Abstract
Spermatogenesis defects concern millions of men worldwide, yet the vast majority remains undiagnosed. Here we report men with primary infertility due to multiple morphological abnormalities of the sperm flagella with severe disorganization of the sperm axoneme, a microtubule-based structure highly conserved throughout evolution. Whole-exome sequencing was performed on 78 patients allowing the identification of 22 men with bi-allelic mutations in DNAH1 (n = 6), CFAP43 (n = 10), and CFAP44 (n = 6). CRISPR/Cas9 created homozygous CFAP43/44 male mice that were infertile and presented severe flagellar defects confirming the human genetic results. Immunoelectron and stimulated-emission-depletion microscopy performed on CFAP43 and CFAP44 orthologs in Trypanosoma brucei evidenced that both proteins are located between the doublet microtubules 5 and 6 and the paraflagellar rod. Overall, we demonstrate that CFAP43 and CFAP44 have a similar structure with a unique axonemal localization and are necessary to produce functional flagella in species ranging from Trypanosoma to human. Asthenozoospermia is a major cause of male infertility, and multiple morphological abnormalities of the flagella (MMAF) is a particularly severe form. Here, using whole-exome sequencing of 78 MMAF patients, the authors identify mutations in two WDR proteins, CFAP43 and CFAP44, and confirm that these proteins are required for flagellogenesis in mouse and Trypanosoma brucei.
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Vincensini L, Blisnick T, Bertiaux E, Hutchinson S, Georgikou C, Ooi CP, Bastin P. Flagellar incorporation of proteins follows at least two different routes in trypanosomes. Biol Cell 2017; 110:33-47. [DOI: 10.1111/boc.201700052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/19/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Laetitia Vincensini
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Thierry Blisnick
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Eloïse Bertiaux
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Sebastian Hutchinson
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Christina Georgikou
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Cher-Pheng Ooi
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
| | - Philippe Bastin
- Trypanosome Cell Biology Unit; Institut Pasteur & INSERM U1201; Paris 75015 France
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Wilson CS, Chang AJ, Greene R, Machado S, Parsons MW, Takats TA, Zambetti LJ, Springer AL. Knockdown of Inner Arm Protein IC138 in Trypanosoma brucei Causes Defective Motility and Flagellar Detachment. PLoS One 2015; 10:e0139579. [PMID: 26555902 PMCID: PMC4640498 DOI: 10.1371/journal.pone.0139579] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 09/15/2015] [Indexed: 12/23/2022] Open
Abstract
Motility in the protozoan parasite Trypanosoma brucei is conferred by a single flagellum, attached alongside the cell, which moves the cell forward using a beat that is generated from tip-to-base. We are interested in characterizing components that regulate flagellar beating, in this study we extend the characterization of TbIC138, the ortholog of a dynein intermediate chain that regulates axonemal inner arm dynein f/I1. TbIC138 was tagged In situ-and shown to fractionate with the inner arm components of the flagellum. RNAi knockdown of TbIC138 resulted in significantly reduced protein levels, mild growth defect and significant motility defects. These cells tended to cluster, exhibited slow and abnormal motility and some cells had partially or fully detached flagella. Slight but significant increases were observed in the incidence of mis-localized or missing kinetoplasts. To document development of the TbIC138 knockdown phenotype over time, we performed a detailed analysis of flagellar detachment and motility changes over 108 hours following induction of RNAi. Abnormal motility, such as slow twitching or irregular beating, was observed early, and became progressively more severe such that by 72 hours-post-induction, approximately 80% of the cells were immotile. Progressively more cells exhibited flagellar detachment over time, but this phenotype was not as prevalent as immotility, affecting less than 60% of the population. Detached flagella had abnormal beating, but abnormal beating was also observed in cells with no flagellar detachment, suggesting that TbIC138 has a direct, or primary, effect on the flagellar beat, whereas detachment is a secondary phenotype of TbIC138 knockdown. Our results are consistent with the role of TbIC138 as a regulator of motility, and has a phenotype amenable to more extensive structure-function analyses to further elucidate its role in the control of flagellar beat in T. brucei.
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Affiliation(s)
- Corinne S. Wilson
- Department of Biology, Siena College, Loudonville, New York, United States of America
| | - Alex J. Chang
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Rebecca Greene
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts, United States of America
| | - Sulynn Machado
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Matthew W. Parsons
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Taylor A. Takats
- Department of Biology, Siena College, Loudonville, New York, United States of America
| | - Luke J. Zambetti
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Amy L. Springer
- Department of Biology, Siena College, Loudonville, New York, United States of America
- * E-mail:
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Mukhopadhyay AG, Dey CS. Two-headed outer- and inner-arm dyneins of Leishmania sp bear conserved IQ-like motifs. Biochem Biophys Rep 2015; 4:283-290. [PMID: 29124215 PMCID: PMC5669419 DOI: 10.1016/j.bbrep.2015.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/01/2015] [Accepted: 10/06/2015] [Indexed: 11/25/2022] Open
Abstract
Dyneins are high molecular weight microtubule based motor proteins responsible for beating of the flagellum. The flagellum is important for the viability of trypanosomes like Leishmania. However, very little is known about dynein and its role in flagellar motility in such trypanosomatid species. Here, we have identified genes in five species of Leishmania that code for outer-arm dynein (OAD) heavy chains α and β, and inner-arm dynein (IAD) heavy chains 1α and 1β using BLAST and MSA. Our sequence analysis indicates that unlike the three-headed outer-arm dyneins of Chlamydomonas and Tetrahymena, the outer-arm dyneins of the genus Leishmania are two-headed, lacking the γ chain like that of metazoans. N-terminal sequence analysis revealed a conserved IQ-like calmodulin binding motif in the outer-arm α and inner-arm 1α dynein heavy chain in the five species of Leishmania similar to Chlamydomonas reinhardtii outer-arm γ. It was predicted that both motifs were incapable of binding calmodulin. Phosphorylation site prediction revealed conserved serine and threonine residues in outer-arm dynein α and inner-arm 1α as putative phosphorylation sites exclusive to Leishmania but not in Trypanosoma brucei suggesting that regulation of dynein activity might be via phosphorylation of these IQ-like motifs in Leishmania sp. Identified outer and inner-arm dynein heavy chain genes in five Leishmania species. Outer-arm dyneins of the genus Leishmania are two-headed like metazoans. Conserved IQ-like motif present in outer-arm α and inner-arm 1α in Leishmania sp. Conserved serine and threonine residues in dynein arms exclusive to Leishmania sp. Possible regulation of dynein activity via phosphorylation of these IQ-like motifs.
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15
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Kalel VC, Schliebs W, Erdmann R. Identification and functional characterization of Trypanosoma brucei peroxin 16. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2326-37. [PMID: 26025675 DOI: 10.1016/j.bbamcr.2015.05.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 05/22/2015] [Accepted: 05/24/2015] [Indexed: 12/01/2022]
Abstract
Protozoan parasites of the family Trypanosomatidae infect humans as well as livestock causing devastating diseases like sleeping sickness, Chagas disease, and Leishmaniasis. These parasites compartmentalize glycolytic enzymes within unique organelles, the glycosomes. Glycosomes represent a subclass of peroxisomes and they are essential for the parasite survival. Hence, disruption of glycosome biogenesis is an attractive drug target for these Neglected Tropical Diseases (NTDs). Peroxin 16 (PEX16) plays an essential role in peroxisomal membrane protein targeting and de novo biogenesis of peroxisomes from endoplasmic reticulum (ER). We identified trypanosomal PEX16 based on specific sequence characteristics and demonstrate that it is an integral glycosomal membrane protein of procyclic and bloodstream form trypanosomes. RNAi mediated partial knockdown of Trypanosoma brucei PEX16 in bloodstream form trypanosomes led to severe ATP depletion, motility defects and cell death. Microscopic and biochemical analysis revealed drastic reduction in glycosome number and mislocalization of the glycosomal matrix enzymes to the cytosol. Asymmetry of the localization of the remaining glycosomes was observed with a severe depletion in the posterior part. The results demonstrate that trypanosomal PEX16 is essential for glycosome biogenesis and thereby, provides a potential drug target for sleeping sickness and related diseases.
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Affiliation(s)
- Vishal C Kalel
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Germany
| | - Wolfgang Schliebs
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Germany
| | - Ralf Erdmann
- Department of Systems Biochemistry, Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Ruhr-University Bochum, Germany.
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Insect stage-specific adenylate cyclases regulate social motility in African trypanosomes. EUKARYOTIC CELL 2014; 14:104-12. [PMID: 25416239 DOI: 10.1128/ec.00217-14] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sophisticated systems for cell-cell communication enable unicellular microbes to act as multicellular entities capable of group-level behaviors that are not evident in individuals. These group behaviors influence microbe physiology, and the underlying signaling pathways are considered potential drug targets in microbial pathogens. Trypanosoma brucei is a protozoan parasite that causes substantial human suffering and economic hardship in some of the most impoverished regions of the world. T. brucei lives on host tissue surfaces during transmission through its tsetse fly vector, and cultivation on surfaces causes the parasites to assemble into multicellular communities in which individual cells coordinate their movements in response to external signals. This behavior is termed "social motility," based on its similarities with surface-induced social motility in bacteria, and it demonstrates that trypanosomes are capable of group-level behavior. Mechanisms governing T. brucei social motility are unknown. Here we report that a subset of receptor-type adenylate cyclases (ACs) in the trypanosome flagellum regulate social motility. RNA interference-mediated knockdown of adenylate cyclase 6 (AC6), or dual knockdown of AC1 and AC2, causes a hypersocial phenotype but has no discernible effect on individual cells in suspension culture. Mutation of the AC6 catalytic domain phenocopies AC6 knockdown, demonstrating that loss of adenylate cyclase activity is responsible for the phenotype. Notably, knockdown of other ACs did not affect social motility, indicating segregation of AC functions. These studies reveal interesting parallels in systems that control social behavior in trypanosomes and bacteria and provide insight into a feature of parasite biology that may be exploited for novel intervention strategies.
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Abstract
Trypanosoma brucei is a pathogenic unicellular eukaryote that infects humans and other mammals in sub-Saharan Africa. A central feature of trypanosome biology is the single flagellum of the parasite, which is an essential and multifunctional organelle that facilitates cell propulsion, controls cell morphogenesis and directs cytokinesis. Moreover, the flagellar membrane is a specialized subdomain of the cell surface that mediates attachment to host tissues and harbours multiple virulence factors. In this Review, we discuss the structure, assembly and function of the trypanosome flagellum, including canonical roles in cell motility as well as novel and emerging roles in cell morphogenesis and host-parasite interactions.
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Affiliation(s)
- Gerasimos Langousis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095
| | - Kent L. Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095
- Molecular Biology Institute, University of California, Los Angeles, CA90095
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18
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Subota I, Julkowska D, Vincensini L, Reeg N, Buisson J, Blisnick T, Huet D, Perrot S, Santi-Rocca J, Duchateau M, Hourdel V, Rousselle JC, Cayet N, Namane A, Chamot-Rooke J, Bastin P. Proteomic analysis of intact flagella of procyclic Trypanosoma brucei cells identifies novel flagellar proteins with unique sub-localization and dynamics. Mol Cell Proteomics 2014; 13:1769-86. [PMID: 24741115 DOI: 10.1074/mcp.m113.033357] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Cilia and flagella are complex organelles made of hundreds of proteins of highly variable structures and functions. Here we report the purification of intact flagella from the procyclic stage of Trypanosoma brucei using mechanical shearing. Structural preservation was confirmed by transmission electron microscopy that showed that flagella still contained typical elements such as the membrane, the axoneme, the paraflagellar rod, and the intraflagellar transport particles. It also revealed that flagella severed below the basal body, and were not contaminated by other cytoskeletal structures such as the flagellar pocket collar or the adhesion zone filament. Mass spectrometry analysis identified a total of 751 proteins with high confidence, including 88% of known flagellar components. Comparison with the cell debris fraction revealed that more than half of the flagellum markers were enriched in flagella and this enrichment criterion was taken into account to identify 212 proteins not previously reported to be associated to flagella. Nine of these were experimentally validated including a 14-3-3 protein not yet reported to be associated to flagella and eight novel proteins termed FLAM (FLAgellar Member). Remarkably, they localized to five different subdomains of the flagellum. For example, FLAM6 is restricted to the proximal half of the axoneme, no matter its length. In contrast, FLAM8 is progressively accumulating at the distal tip of growing flagella and half of it still needs to be added after cell division. A combination of RNA interference and Fluorescence Recovery After Photobleaching approaches demonstrated very different dynamics from one protein to the other, but also according to the stage of construction and the age of the flagellum. Structural proteins are added to the distal tip of the elongating flagellum and exhibit slow turnover whereas membrane proteins such as the arginine kinase show rapid turnover without a detectible polarity.
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Affiliation(s)
- Ines Subota
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Daria Julkowska
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | | | - Nele Reeg
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Johanna Buisson
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Thierry Blisnick
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Diego Huet
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Sylvie Perrot
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Julien Santi-Rocca
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581
| | - Magalie Duchateau
- §Proteomics Platform, Institut Pasteur, ¶Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur & CNRS UMR3528
| | - Véronique Hourdel
- §Proteomics Platform, Institut Pasteur, ¶Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur & CNRS UMR3528
| | | | - Nadège Cayet
- ‖Imagopole Platform, Institut Pasteur, Paris, France
| | | | - Julia Chamot-Rooke
- §Proteomics Platform, Institut Pasteur, ¶Structural Mass Spectrometry and Proteomics Unit, Institut Pasteur & CNRS UMR3528
| | - Philippe Bastin
- From the ‡Trypanosome Cell Biology Unit, Institut Pasteur & CNRS URA2581,
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Kisalu NK, Langousis G, Bentolila LA, Ralston KS, Hill KL. Mouse infection and pathogenesis by Trypanosoma brucei motility mutants. Cell Microbiol 2014; 16:912-24. [PMID: 24286532 DOI: 10.1111/cmi.12244] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/14/2013] [Accepted: 11/15/2013] [Indexed: 12/27/2022]
Abstract
The flagellum of Trypanosoma brucei is an essential and multifunctional organelle that drives parasite motility and is receiving increased attention as a potential drug target. In the mammalian host, parasite motility is suspected to contribute to infection and disease pathogenesis. However, it has not been possible to test this hypothesis owing to lack of motility mutants that are viable in the bloodstream life cycle stage that infects the mammalian host. We recently identified a bloodstream-form motility mutant in 427-derived T. brucei in which point mutations in the LC1 dynein subunit disrupt propulsive motility but do not affect viability. These mutants have an actively beating flagellum, but cannot translocate. Here we demonstrate that the LC1 point mutant fails to show enhanced cell motility upon increasing viscosity of the surrounding medium, which is a hallmark of wild type T. brucei, thus indicating that motility of the mutant is fundamentally altered compared with wild type cells. We next used the LC1 point mutant to assess the influence of trypanosome motility on infection in mice. Wesurprisingly found that disrupting parasite motility has no discernible effect on T. brucei bloodstream infection. Infection time-course, maximum parasitaemia, number of waves of parasitaemia, clinical features and disease outcome are indistinguishable between motility mutant and control parasites. Our studies provide an important step toward understanding the contribution of parasite motility to infection and a foundation for future investigations of T. brucei interaction with the mammalian host.
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Affiliation(s)
- Neville K Kisalu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
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20
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Rotureau B, Ooi CP, Huet D, Perrot S, Bastin P. Forward motility is essential for trypanosome infection in the tsetse fly. Cell Microbiol 2013; 16:425-33. [PMID: 24134537 DOI: 10.1111/cmi.12230] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 10/08/2013] [Accepted: 10/09/2013] [Indexed: 11/29/2022]
Abstract
African trypanosomes are flagellated protozoan parasites transmitted by the bite of tsetse flies and responsible for sleeping sickness in humans. Their complex development in the tsetse digestive tract requires several differentiation and migration steps that are thought to rely on trypanosome motility. We used a functional approach in vivo to demonstrate that motility impairment prevents trypanosomes from developing in their vector. Deletion of the outer dynein arm component DNAI1 results in strong motility defects but cells remain viable in culture. However, although these mutant trypanosomes could infect the tsetse fly midgut, they were neither able to reach the foregut nor able to differentiate into the next stage, thus failing to complete their parasite cycle. This is the first in vivo demonstration that trypanosome motility is essential for the accomplishment of the parasite cycle.
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Affiliation(s)
- Brice Rotureau
- Trypanosome Cell Biology Unit, Institut Pasteur & CNRS, URA 2581, 25, rue du Docteur Roux, 75015, Paris, France
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Nguyen HT, Sandhu J, Langousis G, Hill KL. CMF22 is a broadly conserved axonemal protein and is required for propulsive motility in Trypanosoma brucei. EUKARYOTIC CELL 2013; 12:1202-13. [PMID: 23851336 PMCID: PMC3811564 DOI: 10.1128/ec.00068-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 07/02/2013] [Indexed: 12/23/2022]
Abstract
The eukaryotic flagellum (or cilium) is a broadly conserved organelle that provides motility for many pathogenic protozoa and is critical for normal development and physiology in humans. Therefore, defining core components of motile axonemes enhances understanding of eukaryotic biology and provides insight into mechanisms of inherited and infectious diseases in humans. In this study, we show that component of motile flagella 22 (CMF22) is tightly associated with the flagellar axoneme and is likely to have been present in the last eukaryotic common ancestor. The CMF22 amino acid sequence contains predicted IQ and ATPase associated with a variety of cellular activities (AAA) motifs that are conserved among CMF22 orthologues in diverse organisms, hinting at the importance of these domains in CMF22 function. Knockdown by RNA interference (RNAi) and rescue with an RNAi-immune mRNA demonstrated that CMF22 is required for propulsive cell motility in Trypanosoma brucei. Loss of propulsive motility in CMF22-knockdown cells was due to altered flagellar beating patterns, rather than flagellar paralysis, indicating that CMF22 is essential for motility regulation and likely functions as a fundamental regulatory component of motile axonemes. CMF22 association with the axoneme is weakened in mutants that disrupt the nexin-dynein regulatory complex, suggesting potential interaction with this complex. Our results provide insight into the core machinery required for motility of eukaryotic flagella.
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Affiliation(s)
- HoangKim T. Nguyen
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Jaspreet Sandhu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Gerasimos Langousis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Kent L. Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, California, USA
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22
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Novel bilobe components in Trypanosoma brucei identified using proximity-dependent biotinylation. EUKARYOTIC CELL 2012; 12:356-67. [PMID: 23264645 DOI: 10.1128/ec.00326-12] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The trypanosomes are a family of parasitic protists of which the African trypanosome, Trypanosoma brucei, is the best characterized. The complex and highly ordered cytoskeleton of T. brucei has been shown to play vital roles in its biology but remains difficult to study, in large part owing to the intractability of its constituent proteins. Existing methods of protein identification, such as bioinformatic analysis, generation of monoclonal antibody panels, proteomics, affinity purification, and yeast two-hybrid screens, all have drawbacks. Such deficiencies-troublesome proteins and technical limitations-are common not only to T. brucei but also to many other protists, many of which are even less well studied. Proximity-dependent biotin identification (BioID) is a recently developed technique that allows forward screens for interaction partners and near neighbors in a native environment with no requirement for solubility in nonionic detergent. As such, it is extremely well suited to the exploration of the cytoskeleton. In this project, BioID was adapted for use in T. brucei. The trypanosome bilobe, a discrete cytoskeletal structure with few known protein components, represented an excellent test subject. Use of the bilobe protein TbMORN1 as a probe resulted in the identification of seven new bilobe constituents and two new flagellum attachment zone proteins. This constitutes the first usage of BioID on a largely uncharacterized structure, and demonstrates its utility in identifying new components of such a structure. This remarkable success validates BioID as a new tool for the study of unicellular eukaryotes in particular and the eukaryotic cytoskeleton in general.
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Yu Z, Liu Y, Li Z. Structure-function relationship of the Polo-like kinase in Trypanosoma brucei. J Cell Sci 2012; 125:1519-30. [PMID: 22275435 PMCID: PMC3336379 DOI: 10.1242/jcs.094243] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2011] [Indexed: 12/19/2022] Open
Abstract
Polo-like kinases (Plks) play multiple roles in mitosis and cytokinesis in eukaryotes and are characterized by the C-terminal Polo-box domain (PBD), which is implicated in binding to Plk substrates, targeting Plk and regulating Plk activity. The Plk homolog in Trypanosoma brucei (TbPLK) possesses a similar architecture, but it lacks the crucial residues involved in substrate binding and regulates cytokinesis but not mitosis. Little is known about the regulation of TbPLK and the role of the PBD in TbPLK localization and function. Here, we addressed the requirement of the kinase activity and the PBD for TbPLK localization and function through coupling RNAi of endogenous TbPLK with ectopic expression of TbPLK mutants. We demonstrate that the kinase activity and phosphorylation of two threonine residues, Thr198 and Thr202, in the activation loop (T-loop) of the kinase domain are essential for TbPLK function but not for TbPLK localization. Deletion of the PBD abolishes TbPLK localization, but the PBD itself is not correctly targeted, indicating that TbPLK localization requires both the PBD and the kinase domain. Surprisingly, the kinase domain of TbPLK, but not the PBD, binds to its substrates TbCentrin2 and p110, suggesting that TbPLK might interact with its substrate through different mechanisms. Finally, the PBD interacts with the kinase domain of TbPLK and inhibits its activity, and this inhibition is relieved when Thr198 is phosphorylated. Together, these results suggest an essential role of T-loop phosphorylation in TbPLK activation and crucial roles of the PBD in regulating TbPLK activity and localization.
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Affiliation(s)
- Zhonglian Yu
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Yi Liu
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
| | - Ziyin Li
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin Street, Houston, TX 77030, USA
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King SM. Integrated control of axonemal dynein AAA(+) motors. J Struct Biol 2012; 179:222-8. [PMID: 22406539 DOI: 10.1016/j.jsb.2012.02.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/13/2012] [Accepted: 02/16/2012] [Indexed: 11/17/2022]
Abstract
Axonemal dyneins are AAA(+) enzymes that convert ATP hydrolysis to mechanical work. This leads to the sliding of doublet microtubules with respect to each other and ultimately the generation of ciliary/flagellar beating. However, in order for useful work to be generated, the action of individual dynein motors must be precisely controlled. In addition, cells modulate the motility of these organelles through a variety of second messenger systems and these signals too must be integrated by the dynein motors to yield an appropriate output. This review describes the current status of efforts to understand dynein control mechanisms and their connectivity focusing mainly on studies of the outer dynein arm from axonemes of the unicellular biflagellate green alga Chlamydomonas.
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Affiliation(s)
- Stephen M King
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
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Dacheux D, Landrein N, Thonnus M, Gilbert G, Sahin A, Wodrich H, Robinson DR, Bonhivers M. A MAP6-related protein is present in protozoa and is involved in flagellum motility. PLoS One 2012; 7:e31344. [PMID: 22355359 PMCID: PMC3280300 DOI: 10.1371/journal.pone.0031344] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 01/06/2012] [Indexed: 12/25/2022] Open
Abstract
In vertebrates the microtubule-associated proteins MAP6 and MAP6d1 stabilize cold-resistant microtubules. Cilia and flagella have cold-stable microtubules but MAP6 proteins have not been identified in these organelles. Here, we describe TbSAXO as the first MAP6-related protein to be identified in a protozoan, Trypanosoma brucei. Using a heterologous expression system, we show that TbSAXO is a microtubule stabilizing protein. Furthermore we identify the domains of the protein responsible for microtubule binding and stabilizing and show that they share homologies with the microtubule-stabilizing Mn domains of the MAP6 proteins. We demonstrate, in the flagellated parasite, that TbSAXO is an axonemal protein that plays a role in flagellum motility. Lastly we provide evidence that TbSAXO belongs to a group of MAP6-related proteins (SAXO proteins) present only in ciliated or flagellated organisms ranging from protozoa to mammals. We discuss the potential roles of the SAXO proteins in cilia and flagella function.
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Affiliation(s)
- Denis Dacheux
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, Institut Polytechnique de Bordeaux, UMR 5234, Bordeaux, France
| | - Nicolas Landrein
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Magali Thonnus
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Guillaume Gilbert
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Annelise Sahin
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Harald Wodrich
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Derrick R. Robinson
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
| | - Mélanie Bonhivers
- Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, UMR 5234, Bordeaux, France
- Microbiologie Fondamentale et Pathogénicité, CNRS, UMR 5234, Bordeaux, France
- * E-mail:
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Lacomble S, Vaughan S, Deghelt M, Moreira-Leite FF, Gull K. A Trypanosoma brucei protein required for maintenance of the flagellum attachment zone and flagellar pocket ER domains. Protist 2011; 163:602-15. [PMID: 22186015 PMCID: PMC3405529 DOI: 10.1016/j.protis.2011.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 10/31/2011] [Accepted: 10/31/2011] [Indexed: 01/24/2023]
Abstract
Trypanosomes and Leishmanias are important human parasites whose cellular architecture is centred on the single flagellum. In trypanosomes, this flagellum is attached to the cell along a complex flagellum attachment zone (FAZ), comprising flagellar and cytoplasmic components, the integrity of which is required for correct cell morphogenesis and division. The cytoplasmic FAZ cytoskeleton is conspicuously associated with a sheet of endoplasmic reticulum termed the ‘FAZ ER’. In the present work, 3D electron tomography of bloodstream form trypanosomes was used to clarify the nature of the FAZ ER. We also identified TbVAP, a T. brucei protein whose knockdown by RNAi in procyclic form cells leads to a dramatic reduction in the FAZ ER, and in the ER associated with the flagellar pocket. TbVAP is an orthologue of VAMP-associated proteins (VAPs), integral ER membrane proteins whose mutation in humans has been linked to familial motor neuron disease. The localisation of tagged TbVAP and the phenotype of TbVAP RNAi in procyclic form trypanosomes are consistent with a function for TbVAP in the maintenance of sub-populations of the ER associated with the FAZ and the flagellar pocket. Nevertheless, depletion of TbVAP did not affect cell viability or cell cycle progression.
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Affiliation(s)
- Sylvain Lacomble
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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King SM, Patel-King RS. Functional architecture of the outer arm dynein conformational switch. J Biol Chem 2011; 287:3108-22. [PMID: 22157010 DOI: 10.1074/jbc.m111.286211] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Dynein light chain 1 (LC1/DNAL1) is one of the most highly conserved components of ciliary axonemal outer arm dyneins, and it associates with both a heavy chain motor unit and tubulin located within the A-tubule of the axonemal outer doublet microtubules. In a variety of model systems, lack of LC1 or expression of mutant forms leads to profound defects in ciliary motility, including the failure of the hydrodynamic coupling needed for ciliary metachronal synchrony, random stalling during the power/recovery stroke transition, an aberrant response to imposed viscous load, and in some cases partial failure of motor assembly. These phenotypes have led to the proposal that LC1 acts as part of a mechanical switch to control motor function in response to alterations in axonemal curvature. Here we have used NMR chemical shift mapping to define the regions perturbed by a series of mutations in the C-terminal domain that yield a range of phenotypic effects on motility. In addition, we have identified the subdomain of LC1 involved in binding microtubules and characterized the consequences of an Asn → Ser alteration within the terminal leucine-rich repeat that in humans causes primary ciliary dyskinesia. Together, these data define a series of functional subdomains within LC1 and allow us to propose a structural model for the organization of the dynein heavy chain-LC1-microtubule ternary complex that is required for the coordinated activity of dynein motors in cilia.
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Affiliation(s)
- Stephen M King
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3305, USA.
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