1
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Cox RM, Papoulas O, Shril S, Lee C, Gardner T, Battenhouse AM, Lee M, Drew K, McWhite CD, Yang D, Leggere JC, Durand D, Hildebrandt F, Wallingford JB, Marcotte EM. Ancient eukaryotic protein interactions illuminate modern genetic traits and disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.26.595818. [PMID: 38853926 PMCID: PMC11160598 DOI: 10.1101/2024.05.26.595818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
All eukaryotes share a common ancestor from roughly 1.5 - 1.8 billion years ago, a single-celled, swimming microbe known as LECA, the Last Eukaryotic Common Ancestor. Nearly half of the genes in modern eukaryotes were present in LECA, and many current genetic diseases and traits stem from these ancient molecular systems. To better understand these systems, we compared genes across modern organisms and identified a core set of 10,092 shared protein-coding gene families likely present in LECA, a quarter of which are uncharacterized. We then integrated >26,000 mass spectrometry proteomics analyses from 31 species to infer how these proteins interact in higher-order complexes. The resulting interactome describes the biochemical organization of LECA, revealing both known and new assemblies. We analyzed these ancient protein interactions to find new human gene-disease relationships for bone density and congenital birth defects, demonstrating the value of ancestral protein interactions for guiding functional genetics today.
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Affiliation(s)
- Rachael M Cox
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ophelia Papoulas
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Shirlee Shril
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - Chanjae Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tynan Gardner
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Anna M Battenhouse
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Muyoung Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Kevin Drew
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Claire D McWhite
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - David Yang
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Janelle C Leggere
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Dannie Durand
- Department of Biological Sciences, Carnegie Mellon University, 4400 5th Avenue Pittsburgh, PA 15213, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA 02215, USA
| | - John B Wallingford
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Edward M Marcotte
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
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2
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Patel MB, Griffin PJ, Olson SF, Dai J, Hou Y, Malik T, Das P, Zhang G, Zhao W, Witman GB, Lechtreck KF. Distribution and bulk flow analyses of the intraflagellar transport (IFT) motor kinesin-2 support an "on-demand" model for Chlamydomonas ciliary length control. Cytoskeleton (Hoboken) 2024. [PMID: 38456596 DOI: 10.1002/cm.21851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/09/2024]
Abstract
Most cells tightly control the length of their cilia. The regulation likely involves intraflagellar transport (IFT), a bidirectional motility of multi-subunit particles organized into trains that deliver building blocks into the organelle. In Chlamydomonas, the anterograde IFT motor kinesin-2 consists of the motor subunits FLA8 and FLA10 and the nonmotor subunit KAP. KAP dissociates from IFT at the ciliary tip and diffuses back to the cell body. This observation led to the diffusion-as-a-ruler model of ciliary length control, which postulates that KAP is progressively sequestered into elongating cilia because its return to the cell body will require increasingly more time, limiting motor availability at the ciliary base, train assembly, building block supply, and ciliary growth. Here, we show that Chlamydomonas FLA8 also returns to the cell body by diffusion. However, more than 95% of KAP and FLA8 are present in the cell body and, at a given time, just ~1% of the motor participates in IFT. After repeated photobleaching of both cilia, IFT of fluorescent kinesin subunits continued indicating that kinesin-2 cycles from the large cell-body pool through the cilia and back. Furthermore, growing and full-length cilia contained similar amounts of kinesin-2 subunits and the size of the motor pool at the base changed only slightly with ciliary length. These observations are incompatible with the diffusion-as-a-ruler model, but rather support an "on-demand model," in which the cargo load of the trains is regulated to assemble cilia of the desired length.
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Affiliation(s)
- Mansi B Patel
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Paul J Griffin
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Spencer F Olson
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Jin Dai
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Yuqing Hou
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Tara Malik
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Poulomi Das
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Gui Zhang
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
| | - Winston Zhao
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - George B Witman
- Department of Radiology, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia, USA
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3
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Bachmaier S, Gould MK, Polatoglou E, Omelianczyk R, Brennand AE, Aloraini MA, Munday JC, Horn D, Boshart M, de Koning HP. Novel kinetoplastid-specific cAMP binding proteins identified by RNAi screening for cAMP resistance in Trypanosoma brucei. Front Cell Infect Microbiol 2023; 13:1204707. [PMID: 37475965 PMCID: PMC10354285 DOI: 10.3389/fcimb.2023.1204707] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/14/2023] [Indexed: 07/22/2023] Open
Abstract
Cyclic AMP signalling in trypanosomes differs from most eukaryotes due to absence of known cAMP effectors and cAMP independence of PKA. We have previously identified four genes from a genome-wide RNAi screen for resistance to the cAMP phosphodiesterase (PDE) inhibitor NPD-001. The genes were named cAMP Response Protein (CARP) 1 through 4. Here, we report an additional six CARP candidate genes from the original sample, after deep sequencing of the RNA interference target pool retrieved after NPD-001 selection (RIT-seq). The resistance phenotypes were confirmed by individual RNAi knockdown. Highest level of resistance to NPD-001, approximately 17-fold, was seen for knockdown of CARP7 (Tb927.7.4510). CARP1 and CARP11 contain predicted cyclic AMP binding domains and bind cAMP as evidenced by capture and competition on immobilised cAMP. CARP orthologues are strongly enriched in kinetoplastid species, and CARP3 and CARP11 are unique to Trypanosoma. Localization data and/or domain architecture of all CARPs predict association with the T. brucei flagellum. This suggests a crucial role of cAMP in flagellar function, in line with the cell division phenotype caused by high cAMP and the known role of the flagellum for cytokinesis. The CARP collection is a resource for discovery of unusual cAMP pathways and flagellar biology.
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Affiliation(s)
- Sabine Bachmaier
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Matthew K. Gould
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Eleni Polatoglou
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Radoslaw Omelianczyk
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Ana E. Brennand
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Maha A. Aloraini
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jane C. Munday
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David Horn
- The Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael Boshart
- Faculty of Biology, Genetics, Ludwig-Maximillians University Munich (LMU), Martinsried, Germany
| | - Harry P. de Koning
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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4
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Kubo S, Black CS, Joachimiak E, Yang SK, Legal T, Peri K, Khalifa AAZ, Ghanaeian A, McCafferty CL, Valente-Paterno M, De Bellis C, Huynh PM, Fan Z, Marcotte EM, Wloga D, Bui KH. Native doublet microtubules from Tetrahymena thermophila reveal the importance of outer junction proteins. Nat Commun 2023; 14:2168. [PMID: 37061538 PMCID: PMC10105768 DOI: 10.1038/s41467-023-37868-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 04/03/2023] [Indexed: 04/17/2023] Open
Abstract
Cilia are ubiquitous eukaryotic organelles responsible for cellular motility and sensory functions. The ciliary axoneme is a microtubule-based cytoskeleton consisting of two central singlets and nine outer doublet microtubules. Cryo-electron microscopy-based studies have revealed a complex network inside the lumen of both tubules composed of microtubule-inner proteins (MIPs). However, the functions of most MIPs remain unknown. Here, we present single-particle cryo-EM-based analyses of the Tetrahymena thermophila native doublet microtubule and identify 42 MIPs. These data shed light on the evolutionarily conserved and diversified roles of MIPs. In addition, we identified MIPs potentially responsible for the assembly and stability of the doublet outer junction. Knockout of the evolutionarily conserved outer junction component CFAP77 moderately diminishes Tetrahymena swimming speed and beat frequency, indicating the important role of CFAP77 and outer junction stability in cilia beating generation and/or regulation.
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Affiliation(s)
- Shintaroh Kubo
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Corbin S Black
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Shun Kai Yang
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Thibault Legal
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Katya Peri
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Ahmad Abdelzaher Zaki Khalifa
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Avrin Ghanaeian
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Caitlyn L McCafferty
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada
| | - Chelsea De Bellis
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Phuong M Huynh
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Zhe Fan
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas, Austin, TX, 78712, USA
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093, Warsaw, Poland.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada.
- Centre de Recherche en Biologie Structurale, McGill University, Montreal, QC, Canada.
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5
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The inner junction protein CFAP20 functions in motile and non-motile cilia and is critical for vision. Nat Commun 2022; 13:6595. [PMID: 36329026 PMCID: PMC9633640 DOI: 10.1038/s41467-022-33820-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/03/2022] [Indexed: 11/06/2022] Open
Abstract
Motile and non-motile cilia are associated with mutually-exclusive genetic disorders. Motile cilia propel sperm or extracellular fluids, and their dysfunction causes primary ciliary dyskinesia. Non-motile cilia serve as sensory/signalling antennae on most cell types, and their disruption causes single-organ ciliopathies such as retinopathies or multi-system syndromes. CFAP20 is a ciliopathy candidate known to modulate motile cilia in unicellular eukaryotes. We demonstrate that in zebrafish, cfap20 is required for motile cilia function, and in C. elegans, CFAP-20 maintains the structural integrity of non-motile cilia inner junctions, influencing sensory-dependent signalling and development. Human patients and zebrafish with CFAP20 mutations both exhibit retinal dystrophy. Hence, CFAP20 functions within a structural/functional hub centered on the inner junction that is shared between motile and non-motile cilia, and is distinct from other ciliopathy-associated domains or macromolecular complexes. Our findings suggest an uncharacterised pathomechanism for retinal dystrophy, and potentially for motile and non-motile ciliopathies in general.
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6
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Gilsoul M, Grisar T, Delgado-Escueta AV, de Nijs L, Lakaye B. Subtle Brain Developmental Abnormalities in the Pathogenesis of Juvenile Myoclonic Epilepsy. Front Cell Neurosci 2019; 13:433. [PMID: 31611775 PMCID: PMC6776584 DOI: 10.3389/fncel.2019.00433] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME), a lifelong disorder that starts during adolescence, is the most common of genetic generalized epilepsy syndromes. JME is characterized by awakening myoclonic jerks and myoclonic-tonic-clonic (m-t-c) grand mal convulsions. Unfortunately, one third of JME patients have drug refractory m-t-c convulsions and these recur in 70-80% who attempt to stop antiepileptic drugs (AEDs). Behavioral studies documented impulsivity, but also impairment of executive functions relying on organization and feedback, which points to prefrontal lobe dysfunction. Quantitative voxel-based morphometry (VBM) revealed abnormalities of gray matter (GM) volumes in cortical (frontal and parietal) and subcortical structures (thalamus, putamen, and hippocampus). Proton magnetic resonance spectroscopy (MRS) found evidence of dysfunction of thalamic neurons. White matter (WM) integrity was disrupted in corpus callosum and frontal WM tracts. Magnetic resonance imaging (MRI) further unveiled anomalies in both GM and WM structures that were already present at the time of seizure onset. Aberrant growth trajectories of brain development occurred during the first 2 years of JME diagnosis. Because of genetic origin, disease causing variants were sought, first by positional cloning, and most recently, by next generation sequencing. To date, only six genes harboring pathogenic variants (GABRA1, GABRD, EFHC1, BRD2, CASR, and ICK) with Mendelian and complex inheritance and covering a limited proportion of the world population, are considered as major susceptibility alleles for JME. Evidence on the cellular role, developmental and cell-type expression profiles of these six diverse JME genes, point to their pathogenic variants driving the first steps of brain development when cell division, expansion, axial, and tangential migration of progenitor cells (including interneuron cortical progenitors) sculpture subtle alterations in brain networks and microcircuits during development. These alterations may explain "microdysgenesis" neuropathology, impulsivity, executive dysfunctions, EEG polyspike waves, and awakening m-t-c convulsions observed in JME patients.
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Affiliation(s)
- Maxime Gilsoul
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Thierry Grisar
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Antonio V. Delgado-Escueta
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Laurence de Nijs
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands
| | - Bernard Lakaye
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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7
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Osinka A, Poprzeczko M, Zielinska MM, Fabczak H, Joachimiak E, Wloga D. Ciliary Proteins: Filling the Gaps. Recent Advances in Deciphering the Protein Composition of Motile Ciliary Complexes. Cells 2019; 8:cells8070730. [PMID: 31319499 PMCID: PMC6678824 DOI: 10.3390/cells8070730] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 07/12/2019] [Accepted: 07/16/2019] [Indexed: 12/15/2022] Open
Abstract
Cilia are highly evolutionarily conserved, microtubule-based cell protrusions present in eukaryotic organisms from protists to humans, with the exception of fungi and higher plants. Cilia can be broadly divided into non-motile sensory cilia, called primary cilia, and motile cilia, which are locomotory organelles. The skeleton (axoneme) of primary cilia is formed by nine outer doublet microtubules distributed on the cilium circumference. In contrast, the skeleton of motile cilia is more complex: in addition to outer doublets, it is composed of two central microtubules and several diverse multi-protein complexes that are distributed periodically along both types of microtubules. For many years, researchers have endeavored to fully characterize the protein composition of ciliary macro-complexes and the molecular basis of signal transduction between these complexes. Genetic and biochemical analyses have suggested that several hundreds of proteins could be involved in the assembly and function of motile cilia. Within the last several years, the combined efforts of researchers using cryo-electron tomography, genetic and biochemical approaches, and diverse model organisms have significantly advanced our knowledge of the ciliary structure and protein composition. Here, we summarize the recent progress in the identification of the subunits of ciliary complexes, their precise intraciliary localization determined by cryo-electron tomography data, and the role of newly identified proteins in cilia.
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Affiliation(s)
- Anna Osinka
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Martyna Poprzeczko
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Magdalena M Zielinska
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
| | - Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
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8
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Loucks CM, Park K, Walker DS, McEwan AH, Timbers TA, Ardiel EL, Grundy LJ, Li C, Johnson JL, Kennedy J, Blacque OE, Schafer W, Rankin CH, Leroux MR. EFHC1, implicated in juvenile myoclonic epilepsy, functions at the cilium and synapse to modulate dopamine signaling. eLife 2019; 8:37271. [PMID: 30810526 PMCID: PMC6392500 DOI: 10.7554/elife.37271] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 02/06/2019] [Indexed: 01/03/2023] Open
Abstract
Neurons throughout the mammalian brain possess non-motile cilia, organelles with varied functions in sensory physiology and cellular signaling. Yet, the roles of cilia in these neurons are poorly understood. To shed light into their functions, we studied EFHC1, an evolutionarily conserved protein required for motile cilia function and linked to a common form of inherited epilepsy in humans, juvenile myoclonic epilepsy (JME). We demonstrate that C. elegans EFHC-1 functions within specialized non-motile mechanosensory cilia, where it regulates neuronal activation and dopamine signaling. EFHC-1 also localizes at the synapse, where it further modulates dopamine signaling in cooperation with the orthologue of an R-type voltage-gated calcium channel. Our findings unveil a previously undescribed dual-regulation of neuronal excitability at sites of neuronal sensory input (cilium) and neuronal output (synapse). Such a distributed regulatory mechanism may be essential for establishing neuronal activation thresholds under physiological conditions, and when impaired, may represent a novel pathomechanism for epilepsy.
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Affiliation(s)
- Catrina M Loucks
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
| | - Kwangjin Park
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
| | - Denise S Walker
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Andrea H McEwan
- Djavad Mowfaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Tiffany A Timbers
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
| | - Evan L Ardiel
- Djavad Mowfaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Laura J Grundy
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
| | - Jacque-Lynne Johnson
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
| | - Julie Kennedy
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - William Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Catharine H Rankin
- Djavad Mowfaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada.,Department of Psychology, University of British Columbia, Vancouver, Canada
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, Canada.,Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
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9
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Stoddard D, Zhao Y, Bayless BA, Gui L, Louka P, Dave D, Suryawanshi S, Tomasi RFX, Dupuis-Williams P, Baroud CN, Gaertig J, Winey M, Nicastro D. Tetrahymena RIB72A and RIB72B are microtubule inner proteins in the ciliary doublet microtubules. Mol Biol Cell 2018; 29:2566-2577. [PMID: 30133348 PMCID: PMC6254578 DOI: 10.1091/mbc.e18-06-0405] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Doublet and triplet microtubules are essential and highly stable core structures of centrioles, basal bodies, cilia, and flagella. In contrast to dynamic cytoplasmic microtubules, their luminal surface is coated with regularly arranged microtubule inner proteins (MIPs). However, the protein composition and biological function(s) of MIPs remain poorly understood. Using genetic, biochemical, and imaging techniques, we identified Tetrahymena RIB72A and RIB72B proteins as ciliary MIPs. Fluorescence imaging of tagged RIB72A and RIB72B showed that both proteins colocalize to Tetrahymena cilia and basal bodies but assemble independently. Cryoelectron tomography of RIB72A and/or RIB72B knockout strains revealed major structural defects in the ciliary A-tubule involving MIP1, MIP4, and MIP6 structures. The defects of individual mutants were complementary in the double mutant. All mutants had reduced swimming speed and ciliary beat frequencies, and high-speed video imaging revealed abnormal highly curved cilia during power stroke. Our results show that RIB72A and RIB72B are crucial for the structural assembly of ciliary A-tubule MIPs and are important for proper ciliary motility.
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Affiliation(s)
- Daniel Stoddard
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02453.,Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ying Zhao
- Department of Molecular, Cellular & Developmental Biology University of Colorado Boulder, Boulder, CO 80309
| | - Brian A Bayless
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Long Gui
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Panagiota Louka
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Drashti Dave
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Swati Suryawanshi
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Raphaël F-X Tomasi
- Department of Mechanics, LadHyX, CNRS and Ecole Polytechnique, 91128 Palaiseau Cedex, France.,Physical Microfluidics and Bioengineering, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Pascale Dupuis-Williams
- UMR-S 1174 Inserm, Universite Paris-Sud, 91405 Orsay Cedex, France.,Ecole Supérieure de Physique et de Chimie Industrielles ParisTech, 75005 Paris, France
| | - Charles N Baroud
- Department of Mechanics, LadHyX, CNRS and Ecole Polytechnique, 91128 Palaiseau Cedex, France.,Physical Microfluidics and Bioengineering, Department of Genomes and Genetics, Institut Pasteur, 75015 Paris, France
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Mark Winey
- Department of Molecular, Cellular & Developmental Biology University of Colorado Boulder, Boulder, CO 80309.,Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Daniela Nicastro
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02453.,Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
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10
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Ichikawa M, Bui KH. Microtubule Inner Proteins: A Meshwork of Luminal Proteins Stabilizing the Doublet Microtubule. Bioessays 2018; 40. [PMID: 29430673 DOI: 10.1002/bies.201700209] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 01/05/2018] [Indexed: 11/11/2022]
Abstract
Motile eukaryotic cilia and flagella are hair-like organelles responsible for cell motility and mucociliary clearance. Using cryo-electron tomography, it has been shown that the doublet microtubule, the cytoskeleton core of the cilia and flagella, has microtubule inner protein structures binding periodically inside its lumen. More recently, single-particle cryo-electron microscopy analyses of isolated doublet microtubules have shown that microtubule inner proteins form a meshwork inside the doublet microtubule. High-resolution structures revealed new types of interactions between the microtubule inner proteins and the tubulin lattice. In addition, they offered insights into the potential roles of microtubule inner proteins in the stabilization and assembly of the doublet microtubule. Herein, we review our new insights into microtubule inner proteins from the doublet microtubule together with the current body of literature on microtubule inner proteins.
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Affiliation(s)
- Muneyoshi Ichikawa
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec, Canada H3A 0C7
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montréal, Québec, Canada H3A 0C7.,Groupe de Recherche Axé sur la Structure des Protéines (GRASP), Montréal, Québec, Canada H3A 0C7
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11
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Kirima J, Oiwa K. Flagellar-associated Protein FAP85 Is a Microtubule Inner Protein That Stabilizes Microtubules. Cell Struct Funct 2017; 43:1-14. [PMID: 29311430 DOI: 10.1247/csf.17023] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Genomics and proteomics studies in Chlamydomonas have revealed that an axoneme is composed of 200-600 types of proteins, including uncharacterized proteins collectively named flagellar-associated proteins (FAPs). Nine FAPs contain the EF-hand motif; however, they have not yet been well characterized. To find components responsible for Chlamydomonas-specific waveform changes coupled with intracellular Ca2+ concentrations, we focused on FAP85, an EF-hand motif-containing FAP specific to Chlamydomonas and its relatives. We cloned the cDNA encoding FAP85, expressed it in Escherichia coli cells, and generated a polyclonal antibody against the expressed protein. Immunoblotting showed that FAP85 was present in every axoneme of several flagellar mutants lacking major axonemal components. Immuno-electron microscopy revealed that anti-FAP85 antibodies were found only on the inner wall of A-tubules of the doublets exposed by N-lauroylsarcosine (Sarkosyl) treatment. The zero-length cross-linker 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) applied to 0.6 M KCl-extracted axonemes generated a 75-kDa complex containing β-tubulin and FAP85. Further characterization of FAP85 and its effects on microtubule dynamics showed that FAP85 binds to tubulin and stabilized microtubules. According to these results, we conclude that FAP85 is a novel member of microtubule-binding proteins, localizing on the inner wall of the A-tubule and stabilizing microtubules.Key words: Chlamydomonas, flagella, doublet microtubule, microtubule inner proteins.
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Affiliation(s)
- Junya Kirima
- Department of Picobiology, Graduate School of Life Science, University of Hyogo
| | - Kazuhiro Oiwa
- Department of Picobiology, Graduate School of Life Science, University of Hyogo.,Advanced ICT Research Institute, National Institute of Information and Communications Technology
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12
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Bower R, Tritschler D, Mills KV, Heuser T, Nicastro D, Porter ME. DRC2/CCDC65 is a central hub for assembly of the nexin-dynein regulatory complex and other regulators of ciliary and flagellar motility. Mol Biol Cell 2017; 29:137-153. [PMID: 29167384 PMCID: PMC5909927 DOI: 10.1091/mbc.e17-08-0510] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 11/13/2017] [Accepted: 11/15/2017] [Indexed: 02/01/2023] Open
Abstract
DRC2 is a subunit of the nexin–dynein regulatory complex linked to primary ciliary dyskinesia. Little is known about the impact of drc2 mutations on axoneme composition and structure. We used proteomic and structural approaches to reveal that DRC2 coassembles with DRC1 to attach the N-DRC to the A-tubule and mediate interactions with other regulatory structures. The nexin–dynein regulatory complex (N-DRC) plays a central role in the regulation of ciliary and flagellar motility. In most species, the N-DRC contains at least 11 subunits, but the specific function of each subunit is unknown. Mutations in three subunits (DRC1, DRC2/CCDC65, DRC4/GAS8) have been linked to defects in ciliary motility in humans and lead to a ciliopathy known as primary ciliary dyskinesia (PCD). Here we characterize the biochemical, structural, and motility phenotypes of two mutations in the DRC2 gene of Chlamydomonas. Using high-resolution proteomic and structural approaches, we find that the C-terminal region of DRC2 is critical for the coassembly of DRC2 and DRC1 to form the base plate of N-DRC and its attachment to the outer doublet microtubule. Loss of DRC2 in drc2 mutants disrupts the assembly of several other N-DRC subunits and also destabilizes the assembly of several closely associated structures such as the inner dynein arms, the radial spokes, and the calmodulin- and spoke-associated complex. Our study provides new insights into the range of ciliary defects that can lead to PCD.
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Affiliation(s)
- Raqual Bower
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Douglas Tritschler
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Kristyn VanderWaal Mills
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
| | - Thomas Heuser
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454.,Vienna Biocenter Core Facilities, 1030 Vienna, Austria
| | - Daniela Nicastro
- Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454.,Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mary E Porter
- Department of Genetics, Cell Biology, and Development, University of Minnesota Medical School, Minneapolis, MN 55455
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13
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Abstract
The axoneme is the main extracellular part of cilia and flagella in eukaryotes. It consists of a microtubule cytoskeleton, which normally comprises nine doublets. In motile cilia, dynein ATPase motor proteins generate sliding motions between adjacent microtubules, which are integrated into a well-orchestrated beating or rotational motion. In primary cilia, there are a number of sensory proteins functioning on membranes surrounding the axoneme. In both cases, as the study of proteomics has elucidated, hundreds of proteins exist in this compartmentalized biomolecular system. In this article, we review the recent progress of structural studies of the axoneme and its components using electron microscopy and X-ray crystallography, mainly focusing on motile cilia. Structural biology presents snapshots (but not live imaging) of dynamic structural change and gives insights into the force generation mechanism of dynein, ciliary bending mechanism, ciliogenesis, and evolution of the axoneme.
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Affiliation(s)
- Takashi Ishikawa
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.,Department of Biology, ETH Zurich, 5232 Villigen PSI, Switzerland
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14
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Mizuno K, Dymek EE, Smith EF. Microtubule binding protein PACRG plays a role in regulating specific ciliary dyneins during microtubule sliding. Cytoskeleton (Hoboken) 2016; 73:703-711. [PMID: 27770595 DOI: 10.1002/cm.21340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 11/11/2022]
Abstract
The complex waveforms characteristic of motile eukaryotic cilia and flagella are produced by the temporally and spatially regulated action of multiple dynein subforms generating sliding between subsets of axonemal microtubules. Multiple protein complexes have been identified that are associated with the doublet microtubules and that mediate regulatory signals between key axonemal structures, such as the radial spokes and central apparatus, and the dynein arm motors; these complexes include the N-DRC, MIA, and CSC complexes. Previous studies have shown that PACRG (parkin co-regulated gene) forms a complex that is anchored to the axonemal doublet microtubules. Loss of PACRG causes defects in ciliary motility and cilia related diseases. Here, we use an in vitro microtubule sliding assay to demonstrate that PACRG and its interactors are part of a signaling pathway that includes the central apparatus, radial spokes and specific inner dynein arm subforms to control dynein-driven microtubule sliding. Using a biochemical approach, our studies also indicate that PACRG interacts with the radial spokes. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Katsutoshi Mizuno
- Center for Developmental Biology, RIKEN 2-2-3 Minatojima-minamimachi, Chuou-ku, Kobe, Japan
| | - Erin E Dymek
- Department of Biological Sciences, Class of 1978 Life Sciences Center Dartmouth College, Hanover, New Hampshire
| | - Elizabeth F Smith
- Department of Biological Sciences, Class of 1978 Life Sciences Center Dartmouth College, Hanover, New Hampshire
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15
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Loucks CM, Bialas NJ, Dekkers MPJ, Walker DS, Grundy LJ, Li C, Inglis PN, Kida K, Schafer WR, Blacque OE, Jansen G, Leroux MR. PACRG, a protein linked to ciliary motility, mediates cellular signaling. Mol Biol Cell 2016; 27:2133-44. [PMID: 27193298 PMCID: PMC4927285 DOI: 10.1091/mbc.e15-07-0490] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 05/09/2016] [Indexed: 01/15/2023] Open
Abstract
Cilia are cellular projections that can be motile to generate fluid flow or nonmotile to enable signaling. Both forms are based on shared components, and proteins involved in ciliary motility, like PACRG, may also function in ciliary signaling. Caenorhabditis elegans PACRG acts in a subset of nonmotile cilia to influence a learning behavior and promote longevity. Cilia are microtubule-based organelles that project from nearly all mammalian cell types. Motile cilia generate fluid flow, whereas nonmotile (primary) cilia are required for sensory physiology and modulate various signal transduction pathways. Here we investigate the nonmotile ciliary signaling roles of parkin coregulated gene (PACRG), a protein linked to ciliary motility. PACRG is associated with the protofilament ribbon, a structure believed to dictate the regular arrangement of motility-associated ciliary components. Roles for protofilament ribbon–associated proteins in nonmotile cilia and cellular signaling have not been investigated. We show that PACRG localizes to a small subset of nonmotile cilia in Caenorhabditis elegans, suggesting an evolutionary adaptation for mediating specific sensory/signaling functions. We find that it influences a learning behavior known as gustatory plasticity, in which it is functionally coupled to heterotrimeric G-protein signaling. We also demonstrate that PACRG promotes longevity in C. elegans by acting upstream of the lifespan-promoting FOXO transcription factor DAF-16 and likely upstream of insulin/IGF signaling. Our findings establish previously unrecognized sensory/signaling functions for PACRG and point to a role for this protein in promoting longevity. Furthermore, our work suggests additional ciliary motility-signaling connections, since EFHC1 (EF-hand containing 1), a potential PACRG interaction partner similarly associated with the protofilament ribbon and ciliary motility, also positively regulates lifespan.
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Affiliation(s)
- Catrina M Loucks
- Department of Molecular Biology and Biochemistry and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Nathan J Bialas
- Department of Molecular Biology and Biochemistry and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | | | - Denise S Walker
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Laura J Grundy
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Chunmei Li
- Department of Molecular Biology and Biochemistry and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - P Nick Inglis
- Department of Molecular Biology and Biochemistry and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Katarzyna Kida
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - William R Schafer
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Oliver E Blacque
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gert Jansen
- Department of Cell Biology, Erasmus MC, 3000 CA, Rotterdam, The Netherlands
| | - Michel R Leroux
- Department of Molecular Biology and Biochemistry and Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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16
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Oda T, Abe T, Yanagisawa H, Kikkawa M. Structure and function of outer dynein arm intermediate and light chain complex. Mol Biol Cell 2016; 27:1051-9. [PMID: 26864626 PMCID: PMC4814214 DOI: 10.1091/mbc.e15-10-0723] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/03/2016] [Indexed: 11/11/2022] Open
Abstract
Cryo–electron tomography and structural labeling show that the intermediate and light chains of the outer dynein arm (ODA) form a distinct complex, designated ODA-Beak, which can transmit mechanosignals from the nexin–dynein regulatory complex to the heavy chains of ODA. The outer dynein arm (ODA) is a molecular complex that drives the beating motion of cilia/flagella. Chlamydomonas ODA is composed of three heavy chains (HCs), two ICs, and 11 light chains (LCs). Although the three-dimensional (3D) structure of the whole ODA complex has been investigated, the 3D configurations of the ICs and LCs are largely unknown. Here we identified the 3D positions of the two ICs and three LCs using cryo–electron tomography and structural labeling. We found that these ICs and LCs were all localized at the root of the outer-inner dynein (OID) linker, designated the ODA-Beak complex. Of interest, the coiled-coil domain of IC2 extended from the ODA-Beak to the outer surface of ODA. Furthermore, we investigated the molecular mechanisms of how the OID linker transmits signals to the ODA-Beak, by manipulating the interaction within the OID linker using a chemically induced dimerization system. We showed that the cross-linking of the OID linker strongly suppresses flagellar motility in vivo. These results suggest that the ICs and LCs of the ODA form the ODA-Beak, which may be involved in mechanosignaling from the OID linker to the HCs.
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Affiliation(s)
- Toshiyuki Oda
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Tatsuki Abe
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan
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17
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Linck RW, Chemes H, Albertini DF. The axoneme: the propulsive engine of spermatozoa and cilia and associated ciliopathies leading to infertility. J Assist Reprod Genet 2016; 33:141-56. [PMID: 26825807 PMCID: PMC4759005 DOI: 10.1007/s10815-016-0652-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/03/2016] [Indexed: 01/08/2023] Open
Affiliation(s)
- Richard W Linck
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Hector Chemes
- Center for Research in Endocrinology, National Research Council, CEDIE-CONICET, Endocrinology Division, Buenos Aires Children's Hospital, Gallo 1330, C1425SEFD, Buenos Aires, Argentina.
| | - David F Albertini
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, 66160, USA. .,The Center for Human Reproduction, New York, NY, USA.
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18
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Zhao Y, Shi J, Winey M, Klymkowsky MW. Identifying domains of EFHC1 involved in ciliary localization, ciliogenesis, and the regulation of Wnt signaling. Dev Biol 2016; 411:257-265. [PMID: 26783883 DOI: 10.1016/j.ydbio.2016.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/16/2015] [Accepted: 01/07/2016] [Indexed: 12/24/2022]
Abstract
EFHC1 encodes a ciliary protein that has been linked to Juvenile Myoclonic Epilepsy. In ectodermal explants, derived from Xenopus laevis embryos, the morpholino-mediated down-regulation of EFHC1b inhibited multiciliated cell formation. In those ciliated cells that did form, axoneme but not basal body formation was inhibited. EFHC1b morphant embryos displayed defects in central nervous system (CNS) and neural crest patterning that were rescued by a EFHC1b-GFP chimera. EFHC1b-GFP localized to ciliary axonemes in epidermal, gastrocoele roof plate, and neural tube cells. In X. laevis there is a link between Wnt signaling and multiciliated cell formation. While down-regulation of EFHC1b led to a ~2-fold increase in the activity of the β-catenin/Wnt-responsive TOPFLASH reporter, EFHC1b-GFP did not inhibit β-catenin activation of TOPFLASH. Wnt8a RNA levels were increased in EFHC1b morphant ectodermal explants and intact embryos, analyzed prior to the on-set of ciliogenesis. Rescue of the EFHC1b MO's ciliary axonemal phenotypes required the entire protein; in contrast, the EFHC1b morpholino's Wnt8a, CNS, and neural crest phenotypes were rescued by a truncated form of EFHC1b. The EFHC1b morpholino's Wnt8a phenotype was also rescued by the injection of RNAs encoding secreted Wnt inhibitors, suggesting that these phenotypes are due to effects on Wnt signaling, rather than the loss of cilia, an observation of potential relevance to understanding EFHC1's role in human neural development.
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Affiliation(s)
- Ying Zhao
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Jianli Shi
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Mark Winey
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Michael W Klymkowsky
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA.
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19
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Williams CL, McIntyre JC, Norris SR, Jenkins PM, Zhang L, Pei Q, Verhey K, Martens JR. Direct evidence for BBSome-associated intraflagellar transport reveals distinct properties of native mammalian cilia. Nat Commun 2014; 5:5813. [PMID: 25504142 PMCID: PMC4284812 DOI: 10.1038/ncomms6813] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 11/07/2014] [Indexed: 01/16/2023] Open
Abstract
Cilia dysfunction underlies a class of human diseases with variable penetrance in different organ systems. Across eukaryotes, intraflagellar transport (IFT) facilitates cilia biogenesis and cargo trafficking, but our understanding of mammalian IFT is insufficient. Here we perform live analysis of cilia ultrastructure, composition and cargo transport in native mammalian tissue using olfactory sensory neurons. Proximal and distal axonemes of these neurons show no bias towards IFT kinesin-2 choice, and Kif17 homodimer is dispensable for distal segment IFT. We identify Bardet-Biedl syndrome proteins (BBSome) as bona fide constituents of IFT in olfactory sensory neurons, and show that they exist in 1:1 stoichiometry with IFT particles. Conversely, subpopulations of peripheral membrane proteins, as well as transmembrane olfactory signalling pathway components, are capable of IFT but with significantly less frequency and/or duration. Our results yield a model for IFT and cargo trafficking in native mammalian cilia and may explain the penetrance of specific ciliopathy phenotypes in olfactory neurons.
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Affiliation(s)
- Corey L. Williams
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, 1200 Newell Drive, PO Box 100267, Gainesville, Florida 32610, USA
| | - Jeremy C. McIntyre
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, 1200 Newell Drive, PO Box 100267, Gainesville, Florida 32610, USA
| | - Stephen R. Norris
- Department of Cell and Developmental Biology, University of Michigan, 109 Zina Pitcher Place, 3041 Biomedical Science Research Building (BSRB), Ann Arbor, Michigan 48109, USA
| | - Paul M. Jenkins
- Department of Pharmacology, University of Michigan Medical School, 1301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109-5632, USA
| | - Lian Zhang
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, 1200 Newell Drive, PO Box 100267, Gainesville, Florida 32610, USA
| | - Qinglin Pei
- Department of Biostatistics, University of Florida, RM5225, 2004 Mowry Road, Gainesville, Florida 32611, USA
| | - Kristen Verhey
- Department of Cell and Developmental Biology, University of Michigan, 109 Zina Pitcher Place, 3041 Biomedical Science Research Building (BSRB), Ann Arbor, Michigan 48109, USA
| | - Jeffrey R. Martens
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, 1200 Newell Drive, PO Box 100267, Gainesville, Florida 32610, USA
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20
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Oda T, Yanagisawa H, Kamiya R, Kikkawa M. A molecular ruler determines the repeat length in eukaryotic cilia and flagella. Science 2014; 346:857-60. [DOI: 10.1126/science.1260214] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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21
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Cavalier-Smith T. The neomuran revolution and phagotrophic origin of eukaryotes and cilia in the light of intracellular coevolution and a revised tree of life. Cold Spring Harb Perspect Biol 2014; 6:a016006. [PMID: 25183828 PMCID: PMC4142966 DOI: 10.1101/cshperspect.a016006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Three kinds of cells exist with increasingly complex membrane-protein targeting: Unibacteria (Archaebacteria, Posibacteria) with one cytoplasmic membrane (CM); Negibacteria with a two-membrane envelope (inner CM; outer membrane [OM]); eukaryotes with a plasma membrane and topologically distinct endomembranes and peroxisomes. I combine evidence from multigene trees, palaeontology, and cell biology to show that eukaryotes and archaebacteria are sisters, forming the clade neomura that evolved ~1.2 Gy ago from a posibacterium, whose DNA segregation and cell division were destabilized by murein wall loss and rescued by the evolving novel neomuran endoskeleton, histones, cytokinesis, and glycoproteins. Phagotrophy then induced coevolving serial major changes making eukaryote cells, culminating in two dissimilar cilia via a novel gliding-fishing-swimming scenario. I transfer Chloroflexi to Posibacteria, root the universal tree between them and Heliobacteria, and argue that Negibacteria are a clade whose OM, evolving in a green posibacterium, was never lost.
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22
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Linck R, Fu X, Lin J, Ouch C, Schefter A, Steffen W, Warren P, Nicastro D. Insights into the structure and function of ciliary and flagellar doublet microtubules: tektins, Ca2+-binding proteins, and stable protofilaments. J Biol Chem 2014; 289:17427-44. [PMID: 24794867 PMCID: PMC4067180 DOI: 10.1074/jbc.m114.568949] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Cilia and flagella are conserved, motile, and sensory cell organelles involved in signal transduction and human disease. Their scaffold consists of a 9-fold array of remarkably stable doublet microtubules (DMTs), along which motor proteins transmit force for ciliary motility and intraflagellar transport. DMTs possess Ribbons of three to four hyper-stable protofilaments whose location, organization, and specialized functions have been elusive. We performed a comprehensive analysis of the distribution and structural arrangements of Ribbon proteins from sea urchin sperm flagella, using quantitative immunobiochemistry, proteomics, immuno-cryo-electron microscopy, and tomography. Isolated Ribbons contain acetylated α-tubulin, β-tubulin, conserved protein Rib45, >95% of the axonemal tektins, and >95% of the calcium-binding proteins, Rib74 and Rib85.5, whose human homologues are related to the cause of juvenile myoclonic epilepsy. DMTs contain only one type of Ribbon, corresponding to protofilaments A11-12-13-1 of the A-tubule. Rib74 and Rib85.5 are associated with the Ribbon in the lumen of the A-tubule. Ribbons contain a single ∼5-nm wide filament, composed of equimolar tektins A, B, and C, which interact with the nexin-dynein regulatory complex. A summary of findings is presented, and the functions of Ribbon proteins are discussed in terms of the assembly and stability of DMTs, ciliary motility, and other microtubule systems.
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Affiliation(s)
- Richard Linck
- From the Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455,
| | - Xiaofeng Fu
- the Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, and
| | - Jianfeng Lin
- the Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, and
| | - Christna Ouch
- From the Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Alexandra Schefter
- From the Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Walter Steffen
- the Institute of Molecular and Cell Physiology, Medical School, Hannover, 30625 Hannover, Germany
| | - Peter Warren
- the Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, and
| | - Daniela Nicastro
- the Biology Department and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, and
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Yanagisawa HA, Mathis G, Oda T, Hirono M, Richey EA, Ishikawa H, Marshall WF, Kikkawa M, Qin H. FAP20 is an inner junction protein of doublet microtubules essential for both the planar asymmetrical waveform and stability of flagella in Chlamydomonas. Mol Biol Cell 2014; 25:1472-83. [PMID: 24574454 PMCID: PMC4004596 DOI: 10.1091/mbc.e13-08-0464] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The question of what proteins compose the junctions between two tubules in doublet microtubules is long-standing. Here a conserved flagellar protein, FAP20, is shown to be an inner junction component important for stabilizing the axoneme and scaffolding intra–B-tubular structures required for a planar asymmetrical waveform. The axoneme—the conserved core of eukaryotic cilia and flagella—contains highly specialized doublet microtubules (DMTs). A long-standing question is what protein(s) compose the junctions between two tubules in DMT. Here we identify a highly conserved flagellar-associated protein (FAP), FAP20, as an inner junction (IJ) component. The flagella of Chlamydomonas FAP20 mutants have normal length but beat with an abnormal symmetrical three-dimensional pattern. In addition, the mutant axonemes are liable to disintegrate during beating, implying that interdoublet connections may be weakened. Conventional electron microscopy shows that the mutant axonemes lack the IJ, and cryo–electron tomography combined with a structural labeling method reveals that the labeled FAP20 localizes at the IJ. The mutant axonemes also lack doublet-specific beak structures, which are localized in the proximal portion of the axoneme and may be involved in planar asymmetric flagellar bending. FAP20 itself, however, may not be a beak component, because uniform localization of FAP20 along the entire length of all nine DMTs is inconsistent with the beak's localization. FAP20 is the first confirmed component of the IJ. Our data also suggest that the IJ is important for both stabilizing the axoneme and scaffolding intra–B-tubular substructures required for a planar asymmetrical waveform.
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Affiliation(s)
- Haru-aki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Biology, Texas A&M University, College Station, TX 77843 Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158
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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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25
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Bower R, Tritschler D, Vanderwaal K, Perrone CA, Mueller J, Fox L, Sale WS, Porter ME. The N-DRC forms a conserved biochemical complex that maintains outer doublet alignment and limits microtubule sliding in motile axonemes. Mol Biol Cell 2013; 24:1134-52. [PMID: 23427265 PMCID: PMC3623635 DOI: 10.1091/mbc.e12-11-0801] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The nexin–dynein regulatory complex (N-DRC) is implicated in the control of dynein activity as a structural component of the nexin link. This study identifies several new subunits of the N-DRC and demonstrates for the first time that it forms a discrete biochemical complex that maintains outer doublet integrity and regulates microtubule sliding. The nexin–dynein regulatory complex (N-DRC) is proposed to coordinate dynein arm activity and interconnect doublet microtubules. Here we identify a conserved region in DRC4 critical for assembly of the N-DRC into the axoneme. At least 10 subunits associate with DRC4 to form a discrete complex distinct from other axonemal substructures. Transformation of drc4 mutants with epitope-tagged DRC4 rescues the motility defects and restores assembly of missing DRC subunits and associated inner-arm dyneins. Four new DRC subunits contain calcium-signaling motifs and/or AAA domains and are nearly ubiquitous in species with motile cilia. However, drc mutants are motile and maintain the 9 + 2 organization of the axoneme. To evaluate the function of the N-DRC, we analyzed ATP-induced reactivation of isolated axonemes. Rather than the reactivated bending observed with wild-type axonemes, ATP addition to drc-mutant axonemes resulted in splaying of doublets in the distal region, followed by oscillatory bending between pairs of doublets. Thus the N-DRC provides some but not all of the resistance to microtubule sliding and helps to maintain optimal alignment of doublets for productive flagellar motility. These findings provide new insights into the mechanisms that regulate motility and further highlight the importance of the proximal region of the axoneme in generating flagellar bending.
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Affiliation(s)
- Raqual Bower
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
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26
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Wirschell M, Olbrich H, Werner C, Tritschler D, Bower R, Sale WS, Loges NT, Pennekamp P, Lindberg S, Stenram U, Carlén B, Horak E, Köhler G, Nürnberg P, Nürnberg G, Porter ME, Omran H. The nexin-dynein regulatory complex subunit DRC1 is essential for motile cilia function in algae and humans. Nat Genet 2013; 45:262-8. [PMID: 23354437 DOI: 10.1038/ng.2533] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/21/2012] [Indexed: 01/26/2023]
Abstract
Primary ciliary dyskinesia (PCD) is characterized by dysfunction of respiratory cilia and sperm flagella and random determination of visceral asymmetry. Here, we identify the DRC1 subunit of the nexin-dynein regulatory complex (N-DRC), an axonemal structure critical for the regulation of dynein motors, and show that mutations in the gene encoding DRC1, CCDC164, are involved in PCD pathogenesis. Loss-of-function mutations disrupting DRC1 result in severe defects in assembly of the N-DRC structure and defective ciliary movement in Chlamydomonas reinhardtii and humans. Our results highlight a role for N-DRC integrity in regulating ciliary beating and provide the first direct evidence that mutations in DRC genes cause human disease.
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Affiliation(s)
- Maureen Wirschell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia, USA
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27
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Cryo-electron tomography reveals conserved features of doublet microtubules in flagella. Proc Natl Acad Sci U S A 2011; 108:E845-53. [PMID: 21930914 DOI: 10.1073/pnas.1106178108] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The axoneme forms the essential and conserved core of cilia and flagella. We have used cryo-electron tomography of Chlamydomonas and sea urchin flagella to answer long-standing questions and to provide information about the structure of axonemal doublet microtubules (DMTs). Solving an ongoing controversy, we show that B-tubules of DMTs contain exactly 10 protofilaments (PFs) and that the inner junction (IJ) and outer junction between the A- and B-tubules are fundamentally different. The outer junction, crucial for the initiation of doublet formation, appears to be formed by close interactions between the tubulin subunits of three PFs with unusual tubulin interfaces; other investigators have reported that this junction is weakened by mutations affecting posttranslational modifications of tubulin. The IJ consists of an axially periodic ladder-like structure connecting tubulin PFs of the A- and B-tubules. The recently discovered microtubule inner proteins (MIPs) on the inside of the A- and B-tubules are more complex than previously thought. They are composed of alternating small and large subunits with periodicities of 16 and/or 48 nm. MIP3 forms arches connecting B-tubule PFs, contrary to an earlier report that MIP3 forms the IJ. Finally, the "beak" structures within the B-tubules of Chlamydomonas DMT1, DMT5, and DMT6 are clearly composed of a longitudinal band of proteins repeating with a periodicity of 16 nm. These findings, discussed in relation to genetic and biochemical data, provide a critical foundation for future work on the molecular assembly and stability of the axoneme, as well as its function in motility and sensory transduction.
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Lauwaet T, Smith AJ, Reiner DS, Romijn EP, Wong CCL, Davids BJ, Shah SA, Yates JR, Gillin FD. Mining the Giardia genome and proteome for conserved and unique basal body proteins. Int J Parasitol 2011; 41:1079-92. [PMID: 21723868 DOI: 10.1016/j.ijpara.2011.06.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 05/25/2011] [Accepted: 06/01/2011] [Indexed: 12/27/2022]
Abstract
Giardia lamblia is a flagellated protozoan parasite and a major cause of diarrhoea in humans. Its microtubular cytoskeleton mediates trophozoite motility, attachment and cytokinesis, and is characterised by an attachment disk and eight flagella that are each nucleated in a basal body. To date, only 10 giardial basal body proteins have been identified, including universal signalling proteins that are important for regulating mitosis or differentiation. In this study, we have exploited bioinformatics and proteomic approaches to identify new Giardia basal body proteins and confocal microscopy to confirm their localisation in interphase trophozoites. This approach identified 75 homologs of conserved basal body proteins in the genome including 65 not previously known to be associated with Giardia basal bodies. Thirteen proteins were confirmed to co-localise with centrin to the Giardia basal bodies. We also demonstrate that most basal body proteins localise to additional cytoskeletal structures in interphase trophozoites. This might help to explain the roles of the four pairs of flagella and Giardia-specific organelles in motility and differentiation. A deeper understanding of the composition of the Giardia basal bodies will contribute insights into the complex signalling pathways that regulate its unique cytoskeleton and the biological divergence of these conserved organelles.
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Affiliation(s)
- Tineke Lauwaet
- Department of Pathology, University of California San Diego, San Diego, CA 92103, USA.
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29
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Nakachi M, Nakajima A, Nomura M, Yonezawa K, Ueno K, Endo T, Inaba K. Proteomic profiling reveals compartment-specific, novel functions of ascidian sperm proteins. Mol Reprod Dev 2011; 78:529-49. [DOI: 10.1002/mrd.21341] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 05/18/2011] [Indexed: 11/11/2022]
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Ikeda T. NDP kinase 7 is a conserved microtubule-binding protein preferentially expressed in ciliated cells. Cell Struct Funct 2010; 35:23-30. [PMID: 20215702 DOI: 10.1247/csf.09016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Nucleoside diphosphate (NDP) kinase is an enzyme that synthesizes the nucleoside triphosphates. In mammals, nine sequences (NDK1-NDK9) have been found with domain(s) homologous to the catalytic domain of NDP kinase, and some of them have been shown to associate with sperm flagella. The present study examines the localization of NDK7, for which little information has been available. Database analysis showed that the NDK7 gene is present in organisms with cilia and flagella. Western blotting analyses of various mouse tissues consistently indicated that NDK7 is preferentially expressed in tissues with motile cilia as well as in sperm. Immunofluorescence microscopy revealed that this protein is localized along the entire length of the TritonX-100-insoluble fraction of sperm flagella, possibly in the axonemes. Unexpectedly, however, NDK7 in tracheal epithelia was found in the cell body but not in cilia. Finally, in vitro co-sedimentation assays using recombinant proteins showed that both mouse and Chlamydomonas NDK7 directly bind to microtubules.
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Affiliation(s)
- Takashi Ikeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan
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32
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Abstract
Tektins are insoluble a-helical proteins essential for the construction of cilia and flagella and are found throughout the eukaryotes apart from higher plants.
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Affiliation(s)
- Linda A Amos
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK.
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33
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Are the local adjustments of the relative spatial frequencies of the dynein arms and the β-tubulin monomers involved in the regulation of the “9+2” axoneme? J Theor Biol 2008; 253:74-89. [DOI: 10.1016/j.jtbi.2008.01.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 12/17/2007] [Accepted: 01/24/2008] [Indexed: 11/17/2022]
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34
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Murai MJ, Sassonia RC, Zamboni AH, Conte FF, Martins-de-Souza D, Aparicio R, de Oliveira MG, Lopes-Cendes I. Characterization of the C-terminal half of human juvenile myoclonic epilepsy protein EFHC1: dimer formation blocks Ca2+ and Mg2+ binding to its functional EF-hand. Arch Biochem Biophys 2008; 477:131-8. [PMID: 18593566 DOI: 10.1016/j.abb.2008.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 06/12/2008] [Accepted: 06/12/2008] [Indexed: 10/22/2022]
Abstract
Human EFHC1 is a member of the EF-hand superfamily of Ca(2+)-binding proteins with three DM10 domains of unclear function. Point mutations in the EFHC1 gene are related to juvenile myoclonic epilepsy, a fairly common idiopathic generalized epilepsy. Here, we report the first structural and thermodynamic analyses of the EFHC1C-terminus (residues 403-640; named EFHC1C), comprising the last DM10 domain and the EF-hand motif. Circular dichroism spectroscopy revealed that the secondary structure of EFHC1C is composed by 34% of alpha-helices and 17% of beta-strands. Size exclusion chromatography and mass spectrometry showed that under oxidizing condition EFHC1C dimerizes through the formation of disulfide bond. Tandem mass spectrometry (MS/MS) analysis of peptides generated by trypsin digestion suggests that the Cys575 is involved in intermolecular S-S bond. In addition, DTNB assay showed that each reduced EFHC1C molecule has one accessible free thiol. Isothermal titration calorimetry (ITC) showed that while the interaction between Ca(2+) and EFHC1C is enthalpically driven (DeltaH=-58.6 to -67 kJ/mol and TDeltaS=-22.5 to -31 kJ/mol) the interaction between Mg(2+) and EFHC1C involves an entropic gain, and is approximately 5 times less enthalpically favorable (DeltaH=-11.7 to -14 kJ/mol and TDeltaS=21.9 to 19 kJ/mol) than for Ca(2+) binding. It was also found that under reducing condition Ca(2+) or Mg(2+) ions bind to EFHC1C in a 1/1 molar ratio, while under oxidizing condition this ratio is reduced, showing that EFHC1C dimerization blocks Ca(2+) and Mg(2+) binding.
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Affiliation(s)
- Marcelo J Murai
- Department of Medical Genetics, Faculty of Medical Sciences, Tessália Vieira de Camargo, 126, CEP 13083-970, University of Campinas, UNICAMP, Campinas, SP, Brazil
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35
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Ralston KS, Hill KL. The flagellum of Trypanosoma brucei: new tricks from an old dog. Int J Parasitol 2008; 38:869-84. [PMID: 18472102 DOI: 10.1016/j.ijpara.2008.03.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/03/2008] [Accepted: 03/03/2008] [Indexed: 11/30/2022]
Abstract
African trypanosomes, i.e. Trypanosoma brucei and related sub-species, are devastating human and animal pathogens that cause significant human mortality and limit sustained economic development in sub-Saharan Africa. T. brucei is a highly motile protozoan parasite and coordinated motility is central to both disease pathogenesis in the mammalian host and parasite development in the tsetse fly vector. Therefore, understanding unique aspects of the T. brucei flagellum may uncover novel targets for therapeutic intervention in African sleeping sickness. Moreover, studies of conserved features of the T. brucei flagellum are directly relevant to understanding fundamental aspects of flagellum and cilium function in other eukaryotes, making T. brucei an important model system. The T. brucei flagellum contains a canonical 9+2 axoneme, together with additional features that are unique to kinetoplastids and a few closely-related organisms. Until recently, much of our knowledge of the structure and function of the trypanosome flagellum was based on analogy and inference from other organisms. There has been an explosion in functional studies in T. brucei in recent years, revealing conserved as well as novel and unexpected structural and functional features of the flagellum. Most notably, the flagellum has been found to be an essential organelle, with critical roles in parasite motility, morphogenesis, cell division and immune evasion. This review highlights recent discoveries on the T. brucei flagellum.
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Affiliation(s)
- Katherine S Ralston
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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36
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Suzuki T, Inoue I, Yamagata T, Morita N, Furuichi T, Yamakawa K. Sequential expression of Efhc1/myoclonin1 in choroid plexus and ependymal cell cilia. Biochem Biophys Res Commun 2007; 367:226-33. [PMID: 18164683 DOI: 10.1016/j.bbrc.2007.12.126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 12/19/2007] [Indexed: 11/19/2022]
Abstract
EFHC1 is a gene mutated in patients with idiopathic epilepsies, and encodes the myoclonin1 protein. We here report the distribution of myoclonin1 in mouse. Immunohistochemical analyses revealed that the myoclonin1 first appeared at the roof of hindbrain at embryonic day 10 (E10), and moved on to choroid plexus at E14. At E18, it moved to ventricle walls and disappeared from choroid plexus. From neonatal to adult stages, myoclonin1 was concentrated in the cilia of ependymal cells at ventricle walls. At adult stages, myoclonin1 expression was also observed at tracheal epithelial cilia in lung and at sperm flagella in testis. Specificities of these immunohistochemical signals were verified by using Efhc1-deficient mice as negative controls. Results of Efhc1 mRNA in situ hybridization were also consistent with the immunohistochemical observations. Our findings raise "choroid plexusopathy" or "ciliopathy" as intriguing candidate cascades for the molecular pathology of epilepsies caused by the EFHC1 mutations.
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Affiliation(s)
- Toshimitsu Suzuki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
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37
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Ikeda K, Ikeda T, Morikawa K, Kamiya R. Axonemal localization ofChlamydomonasPACRG, a homologue of the humanParkin-coregulated gene product. ACTA ACUST UNITED AC 2007; 64:814-21. [PMID: 17654607 DOI: 10.1002/cm.20225] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A homologue of mammalian PACRG was identified in Sarkosyl-extracted Chlamydomonas axonemes as a protein that may interact with Rib72 (a component of the protofilament ribbon within the outer doublet microtubules). PACRG is a protein whose expression is co-regulated with the Parkin gene implicated in Parkinson's disease. Although subsequent analyses did not confirm a Rib72-PACRG interaction, both proteins display similar localization in the axoneme. Immuno-localization of PACRG required pretreatment of the axoneme with Sarkosyl, suggesting that the antigen is buried in the wall of the microtubule. Indirect immunofluorescence localized PACRG to the entire length of the axoneme and the basal body, and immuno-electron microscopy showed that the PACRG antigen is densely distributed along the outer doublets in frayed axonemes. In thin-section images, the PACRG signals were frequently found between the A- and B-tubules of adjacent outer doublets. From these and other results, we propose that PACRG is a structural component of the doublet and triplet microtubules possibly involved in inter-tubule linkage.
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Affiliation(s)
- Kazuho Ikeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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38
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Abstract
One by one, mutation-containing mendelian genes that cause monogenic juvenile myoclonic epilepsies (JME) and single nucleotide polymorphisms (SNP)-susceptibility alleles that increase risks for nonmendelian complex JME should fall to the power of molecular genetics. Of 15 chromosome loci, 3 mendelian genes (alpha1-subunit of the GABA(A) receptor [GABRA1], chloride channel 2 gene [CLCN2], and Myoclonin1/EFHC1) and 2 SNP-susceptibility alleles of putative JME genes in epistases (bromodomain-containing protein 2 [BRD2] and connexin [Cx]-36) have been identified, so far. Antiepileptic drugs now can be designed against the specific molecular defects of JME.
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Affiliation(s)
- Antonio V Delgado-Escueta
- David Geffen School of Medicine, University of California Los Angeles Comprehensive Epilepsy Program, VA Greater Los Angeles Healthcare System West Los Angeles, CA, USA
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39
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Downing KH, Sui H. Structural insights into microtubule doublet interactions in axonemes. Curr Opin Struct Biol 2007; 17:253-9. [PMID: 17387011 DOI: 10.1016/j.sbi.2007.03.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2007] [Revised: 02/06/2007] [Accepted: 03/16/2007] [Indexed: 11/28/2022]
Abstract
Coordinated sliding of microtubule doublets, driven by dynein motors, produces periodic beating of eukaryotic cilia and flagella. Recent structural studies of the axoneme, which forms the core of cilia and flagella, have used cryo-electron tomography to reveal new details of the interactions between some of the multitude of proteins that form the axoneme and regulate its movement. Connections between the several types of dyneins, in particular, suggest ways in which their action might be coordinated. Study of the molecular architecture of isolated doublets has provided a structural basis for understanding mechanical properties related to the bending of the axoneme, and has also offered insight into the potential role of doublets in the mechanism of dynein activity regulation.
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Affiliation(s)
- Kenneth H Downing
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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40
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Inaba K. Molecular basis of sperm flagellar axonemes: structural and evolutionary aspects. Ann N Y Acad Sci 2007; 1101:506-26. [PMID: 17363437 DOI: 10.1196/annals.1389.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The axonemes serve as motile machineries in sperm flagella. Although atypical axonemal structures are observed in some cases, 9 + 2 microtubule structure of the axoneme is predominant in many organisms. Several structures are bound to these microtubules and comprise a highly organized protein network. Extensive proteomic analysis of the axonemes has led to find several repeats, domains, and motifs in axonemal proteins. Molecular comparison of subunit composition of axonemal substructures between the ascidian Ciona intestinalis and the green algae Chlamydomonas reinhardtti leads to an intriguing molecular aspect concerning the evolution of intracellular functional complex: The architecture of the axonemes has been well conserved through evolution, but the molecular structure of each axonemal component is not always conserved. In light of domain structure in the axonemal proteins, substructures like outer arm dynein and radial spoke contain a set of domain structures, although some domain-containing subunits are different between these two organisms. Thus, conservation of protein domains within a substructure seems to take precedence over that of each protein ("module-dominant conservation"), which may ultimately result in morphological and functional conservation of the axonemes through evolution.
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Affiliation(s)
- Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, Shizuoka 415-0025, Japan.
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41
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Baron DM, Ralston KS, Kabututu ZP, Hill KL. Functional genomics in Trypanosoma brucei identifies evolutionarily conserved components of motile flagella. J Cell Sci 2007; 120:478-91. [PMID: 17227795 DOI: 10.1242/jcs.03352] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cilia and flagella are highly conserved, complex organelles involved in a variety of important functions. Flagella are required for motility of several human pathogens and ciliary defects lead to a variety of fatal and debilitating human diseases. Many of the major structural components of cilia and flagella are known, but little is known about regulation of flagellar beat. Trypanosoma brucei, the causative agent of African sleeping sickness, provides an excellent model for studying flagellar motility. We have used comparative genomics to identify a core group of 50 genes unique to organisms with motile flagella. These genes, referred to as T. brucei components of motile flagella (TbCMF) include 30 novel genes, and human homologues of many of the TbCMF genes map to loci associated with human ciliary diseases. To characterize TbCMF protein function we used RNA interference to target 41 TbCMF genes. Sedimentation assays and direct observation demonstrated clear motility defects in a majority of these knockdown mutants. Epitope tagging, fluorescence localization and biochemical fractionation demonstrated flagellar localization for several TbCMF proteins. Finally, ultrastructural analysis identified a family of novel TbCMF proteins that function to maintain connections between outer doublet microtubules, suggesting that they are the first identified components of nexin links. Overall, our results provide insights into the workings of the eukaryotic flagellum, identify several novel human disease gene candidates, reveal unique aspects of the trypanosome flagellum and underscore the value of T. brucei as an experimental system for studying flagellar biology.
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Affiliation(s)
- Desiree M Baron
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
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Grisar T, de Nijs L, Chanas G, Léon C, Coumans B, Foidart A, Lakaye B. Some genetic and biochemical aspects of myoclonus. Neurophysiol Clin 2006; 36:271-9. [PMID: 17336771 DOI: 10.1016/j.neucli.2006.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Can a gene defect be responsible for the occurrence in an individual, at a particular age, of such a muscle twitch followed by relaxation called: "myoclonus" and defined as sudden, brief, shock-like movements? Genetic defects could indeed determine a subsequent cascade of molecular events (caused by abnormal encoded proteins) that would produce new aberrant cellular relationships in a particular area of the CNS leading to re-built "myoclonogenic" neuronal networks. This can be illustrated reviewing some inherited neurological entities that are characterized by a predominant myoclonic picture and among which a clear gene defect has been identified. In the second part of this chapter, we will also propose a new point of view on how some structural genes could, under certain conditions, when altered, produced idiopathic generalized epilepsy with myoclonic jerks, taking juvenile myoclonic epilepsy (JME) and the myoclonin (EFHC-1) gene as examples.
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Affiliation(s)
- T Grisar
- Center for Cellular and Molecular Neurobiology, University of Liege, 1, avenue de l'Hôpital, B-36, 4000 Liège, Belgium.
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43
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Setter PW, Malvey-Dorn E, Steffen W, Stephens RE, Linck RW. Tektin interactions and a model for molecular functions. Exp Cell Res 2006; 312:2880-96. [PMID: 16831421 DOI: 10.1016/j.yexcr.2006.05.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 05/25/2006] [Accepted: 05/28/2006] [Indexed: 10/24/2022]
Abstract
Tektins from echinoderm flagella were analyzed for microheterogeneity, self-associations and association with tubulin, resulting in a general model of tektin filament structure and function applicable to most eukaryotic cilia and flagella. Using a new antibody to tektin consensus peptide RPNVELCRD, well-characterized chain-specific antibodies and quantitative gel densitometry, tektins A, B and C were found to be present in equimolar amounts in Sarkosyl-urea-stable filaments. In addition, two isoforms of tektin A are present in half-molar ratios to tektins B and C. Cross-linking of AB filaments indicates in situ nearest neighbor associations of tektin A1B and A2B heterodimers, -trimers, -tetramers and higher oligomers. Soluble purified tektin C is cross-linked as homodimers, trimers and tetramers, but not higher oligomers. Tektin filaments associate with both loosely bound and tightly bound tubulin, and with the latter in a 1:1 molar ratio, implying a specific, periodic association of tightly bound tubulin along the tektin axis. Similarly, in tektin-containing Sarkosyl-stable protofilament ribbons, two polypeptides ( approximately 67/73 kDa, homologues of rib72, efhc1 and efhc2) are present in equimolar ratios to each other and to individual tektins, co-fractionating with loosely bound tubulin. These results suggest a super-coiled arrangement of tektin filaments, the organization of which has important implications for the evolution, assembly and functions of cilia and flagella.
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Affiliation(s)
- Peter W Setter
- Department of Genetics, Cell Biology and Development, University of Minnesota, 321 Church St., Minneapolis, MN 55455, USA
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King SM. Axonemal protofilament ribbons, DM10 domains, and the link to juvenile myoclonic epilepsy. ACTA ACUST UNITED AC 2006; 63:245-53. [PMID: 16572395 DOI: 10.1002/cm.20129] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is a common neurological disorder that results in short uncontrolled muscle contractions and sometimes more severe seizures. Genetic studies have suggested that JME may be caused by mutations in EFHC1. The Efhc1 protein consists of three DM10 domains and a C-terminal region containing a potential Ca2+ -binding motif. In Chlamydomonas, a protein (Rib72) of almost identical domain structure is a component of the protofilament ribbons within the doublet microtubules of the flagellar axoneme. Here I discuss recent work that supports assignment of human Efhc1 as a ciliary component and the resulting implications for the mechanism of disease causation.
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Affiliation(s)
- Stephen M King
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut, USA.
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45
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Sui H, Downing KH. Molecular architecture of axonemal microtubule doublets revealed by cryo-electron tomography. Nature 2006; 442:475-8. [PMID: 16738547 DOI: 10.1038/nature04816] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 04/21/2006] [Indexed: 11/09/2022]
Abstract
The axoneme, which forms the core of eukaryotic flagella and cilia, is one of the largest macromolecular machines, with a structure that is largely conserved from protists to mammals. Microtubule doublets are structural components of axonemes that contain a number of proteins besides tubulin, and are usually found in arrays of nine doublets arranged around two singlet microtubules. Coordinated sliding of adjacent doublets, which involves a host of other proteins in the axoneme, produces periodic beating movements of the axoneme. We have obtained a three-dimensional density map of intact microtubule doublets using cryo-electron tomography and image averaging. Our map, with a resolution of about 3 nm, provides insights into locations of particular proteins within the doublets and the structural features of the doublets that define their mechanical properties. We identify likely candidates for several of these non-tubulin components of the doublets. This work offers insight on how tubulin protofilaments and accessory proteins attach together to form the doublets and provides a structural basis for understanding doublet function in axonemes.
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Affiliation(s)
- Haixin Sui
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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de Nijs L, Lakaye B, Coumans B, Léon C, Ikeda T, Delgado-Escueta AV, Grisar T, Chanas G. EFHC1, a protein mutated in juvenile myoclonic epilepsy, associates with the mitotic spindle through its N-terminus. Exp Cell Res 2006; 312:2872-9. [PMID: 16824517 DOI: 10.1016/j.yexcr.2006.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 04/25/2006] [Accepted: 05/22/2006] [Indexed: 01/23/2023]
Abstract
A novel gene, EFHC1, mutated in juvenile myoclonic epilepsy (JME) encodes a protein with three DM10 domains of unknown function and one putative EF-hand motif. To study the properties of EFHC1, we expressed EGFP-tagged protein in various cell lines. In interphase cells, the fusion protein was present in the cytoplasm and in the nucleus with specific accumulation at the centrosome. During mitosis EGFP-EFHC1 colocalized with the mitotic spindle, especially at spindle poles and with the midbody during cytokinesis. Using a specific antibody, we demonstrated the same distribution of the endogenous protein. Deletion analyses revealed that the N-terminal region of EFHC1 is crucial for the association with the mitotic spindle and the midbody. Our results suggest that EFHC1 could play an important role during cell division.
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Affiliation(s)
- Laurence de Nijs
- Center for Cellular and Molecular Neurobiology, University of Liège, Avenue de l'Hôpital 1, B-36, 4000 Liège, Belgium
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47
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Keller LC, Romijn EP, Zamora I, Yates JR, Marshall WF. Proteomic analysis of isolated chlamydomonas centrioles reveals orthologs of ciliary-disease genes. Curr Biol 2005; 15:1090-8. [PMID: 15964273 DOI: 10.1016/j.cub.2005.05.024] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Revised: 05/06/2005] [Accepted: 05/06/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND The centriole is one of the most enigmatic organelles in the cell. Centrioles are cylindrical, microtubule-based barrels found in the core of the centrosome. Centrioles also act as basal bodies during interphase to nucleate the assembly of cilia and flagella. There are currently only a handful of known centriole proteins. RESULTS We used mass-spectrometry-based MudPIT (multidimensional protein identification technology) to identify the protein composition of basal bodies (centrioles) isolated from the green alga Chlamydomonas reinhardtii. This analysis detected the majority of known centriole proteins, including centrin, epsilon tubulin, and the cartwheel protein BLD10p. By combining proteomic data with information about gene expression and comparative genomics, we identified 45 cross-validated centriole candidate proteins in two classes. Members of the first class of proteins (BUG1-BUG27) are encoded by genes whose expression correlates with flagellar assembly and which therefore may play a role in ciliogenesis-related functions of basal bodies. Members of the second class (POC1-POC18) are implicated by comparative-genomics and -proteomics studies to be conserved components of the centriole. We confirmed centriolar localization for the human homologs of four candidate proteins. Three of the cross-validated centriole candidate proteins are encoded by orthologs of genes (OFD1, NPHP-4, and PACRG) implicated in mammalian ciliary function and disease, suggesting that oral-facial-digital syndrome and nephronophthisis may involve a dysfunction of centrioles and/or basal bodies. CONCLUSIONS By analyzing isolated Chlamydomonas basal bodies, we have been able to obtain the first reported proteomic analysis of the centriole.
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Affiliation(s)
- Lani C Keller
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
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48
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Lindemann CB, Macauley LJ, Lesich KA. The counterbend phenomenon in dynein-disabled rat sperm flagella and what it reveals about the interdoublet elasticity. Biophys J 2005; 89:1165-74. [PMID: 15923232 PMCID: PMC1366601 DOI: 10.1529/biophysj.105.060681] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rat sperm that have been rendered passive by disabling the dynein motors with 50 muM sodium metavanadate and 0.1 mM ATP exhibit an interesting response to imposed bending. When the proximal flagellum is bent with a microprobe, the portion of the flagellum distal to the probe contact point develops a bend in the direction opposite the imposed bend. This "counterbend" is not compatible with a simple elastic beam. It can be satisfactorily explained by the sliding tubule model of flagellar structure but only if there are permanent elastic connections between the outer doublets of the axoneme. The elastic component that contributes the bending torque for the counterbend does not reset to a new equilibrium position after an imposed bend but returns the flagellum to a nearly straight or slightly curved final position after release from the probe. This suggests it is based on fixed, rather than mobile, attachments. It is also disrupted by elastase or trypsin digestion, confirming that it is dependent on a protein linkage. Adopting the assumption that the elasticity is attributed to the nexin links that repeat at 96 nm intervals, we find an apparent elasticity for each link that ranges from 1.6 to 10 x 10(-5) N/m. However, the elasticity is nonlinear and does not follow Hooke's law but appears to decrease with increased stretch. In addition, the responsible elastic elements must be able to stretch to more than 10 times their resting length without breakage to account for the observed counterbend formation. Elasticity created by some type of protein unfolding may be the only viable explanation consistent with both the extreme capacity for extension and the nonlinear character of the restoring force that is observed.
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Affiliation(s)
- Charles B Lindemann
- Department of Biological Sciences, Oakland University, Rochester, Michigan 48309-4476, USA.
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Ikeda T, Ikeda K, Enomoto M, Park MK, Hirono M, Kamiya R. The mouse ortholog of EFHC1 implicated in juvenile myoclonic epilepsy is an axonemal protein widely conserved among organisms with motile cilia and flagella. FEBS Lett 2005; 579:819-22. [PMID: 15670853 DOI: 10.1016/j.febslet.2004.12.070] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Revised: 12/06/2004] [Accepted: 12/20/2004] [Indexed: 11/23/2022]
Abstract
The gene product of EFHC1 recently implicated in juvenile myoclonic epilepsy (JME) was found to be a homolog of Chlamydomonas axonemal protein Rib72, whose homologs are present in a wide variety of organisms that have motile cilia and flagella. Western blot analyses and immunofluorescence localization of the mouse ortholog mRib72-1/Efhc1 indicated that it is indeed abundantly present in sperm flagella and tracheal cilia but only in a small amount in the brain. It is not present in immotile primary cilia. These observations raise the possibility that malfunction of motile cilia is involved in the development of JME.
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Affiliation(s)
- Takashi Ikeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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50
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Arango NA, Pearson EJ, Donahoe PK, Teixeira J. Genomic structure and expression analysis of the mouse testis-specific ribbon protein (Trib) gene. Gene 2005; 343:221-7. [PMID: 15563848 DOI: 10.1016/j.gene.2004.09.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Revised: 08/12/2004] [Accepted: 09/10/2004] [Indexed: 11/17/2022]
Abstract
During our analyses of genes required for the development and function of the mouse gonads, we identified a novel testis-specific mRNA, transcribed from a gene that we have named testis-specific ribbon protein (Trib). In the mouse, Trib is located on chromosome 15, overlapping with and transcribed in the opposite orientation of the meiosis specific gene Smc1beta. The deduced amino acid sequence of testis ribbon (TRIB) protein is highly conserved between human, mouse, and rat and contains the ribbon motifs found in the largely uncharacterized microtubule ribbon protein ribbon43a (RIB43A). We show by Northern blot analyses and reverse transcription-polymerase chain reaction (RT-PCR) that Trib mRNA is specifically expressed in the adult testis. In situ hybridization indicates that Trib is expressed solely in germ cells during the leptotene-pachytene stages of spermatogenesis. The high level of evolutionary conservation and the cellular and temporal expression suggest that Trib may be required for mouse spermatogenesis and male fertility. Here, we describe the genomic structure and expression profile of mouse Trib and compare its homology with other ribbon proteins.
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Affiliation(s)
- Nelson A Arango
- Pediatric Surgical Research Laboratories/WRN1024, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA.
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