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Rabiasz A, Ziętkiewicz E. Schmidtea mediterranea as a Model Organism to Study the Molecular Background of Human Motile Ciliopathies. Int J Mol Sci 2023; 24:ijms24054472. [PMID: 36901899 PMCID: PMC10002865 DOI: 10.3390/ijms24054472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/12/2023] Open
Abstract
Cilia and flagella are evolutionarily conserved organelles that form protrusions on the surface of many growth-arrested or differentiated eukaryotic cells. Due to the structural and functional differences, cilia can be roughly classified as motile and non-motile (primary). Genetically determined dysfunction of motile cilia is the basis of primary ciliary dyskinesia (PCD), a heterogeneous ciliopathy affecting respiratory airways, fertility, and laterality. In the face of the still incomplete knowledge of PCD genetics and phenotype-genotype relations in PCD and the spectrum of PCD-like diseases, a continuous search for new causative genes is required. The use of model organisms has been a great part of the advances in understanding molecular mechanisms and the genetic basis of human diseases; the PCD spectrum is not different in this respect. The planarian model (Schmidtea mediterranea) has been intensely used to study regeneration processes, and-in the context of cilia-their evolution, assembly, and role in cell signaling. However, relatively little attention has been paid to the use of this simple and accessible model for studying the genetics of PCD and related diseases. The recent rapid development of the available planarian databases with detailed genomic and functional annotations prompted us to review the potential of the S. mediterranea model for studying human motile ciliopathies.
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2
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Park K, Leroux MR. Composition, organization and mechanisms of the transition zone, a gate for the cilium. EMBO Rep 2022; 23:e55420. [PMID: 36408840 PMCID: PMC9724682 DOI: 10.15252/embr.202255420] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/08/2022] [Accepted: 10/31/2022] [Indexed: 11/22/2022] Open
Abstract
The cilium evolved to provide the ancestral eukaryote with the ability to move and sense its environment. Acquiring these functions required the compartmentalization of a dynein-based motility apparatus and signaling proteins within a discrete subcellular organelle contiguous with the cytosol. Here, we explore the potential molecular mechanisms for how the proximal-most region of the cilium, termed transition zone (TZ), acts as a diffusion barrier for both membrane and soluble proteins and helps to ensure ciliary autonomy and homeostasis. These include a unique complement and spatial organization of proteins that span from the microtubule-based axoneme to the ciliary membrane; a protein picket fence; a specialized lipid microdomain; differential membrane curvature and thickness; and lastly, a size-selective molecular sieve. In addition, the TZ must be permissive for, and functionally integrates with, ciliary trafficking systems (including intraflagellar transport) that cross the barrier and make the ciliary compartment dynamic. The quest to understand the TZ continues and promises to not only illuminate essential aspects of human cell signaling, physiology, and development, but also to unravel how TZ dysfunction contributes to ciliopathies that affect multiple organ systems, including eyes, kidney, and brain.
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Affiliation(s)
- Kwangjin Park
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
- Present address:
Terry Fox LaboratoryBC CancerVancouverBCCanada
- Present address:
Department of Medical GeneticsUniversity of British ColumbiaVancouverBCCanada
| | - Michel R Leroux
- Department of Molecular Biology and BiochemistrySimon Fraser UniversityBurnabyBCCanada
- Centre for Cell Biology, Development, and DiseaseSimon Fraser UniversityBurnabyBCCanada
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Lechtreck KF, Liu Y, Dai J, Alkhofash RA, Butler J, Alford L, Yang P. Chlamydomonas ARMC2/PF27 is an obligate cargo adapter for intraflagellar transport of radial spokes. eLife 2022; 11:74993. [PMID: 34982025 PMCID: PMC8789290 DOI: 10.7554/elife.74993] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/03/2022] [Indexed: 12/19/2022] Open
Abstract
Intraflagellar transport (IFT) carries proteins into flagella but how IFT trains interact with the large number of diverse proteins required to assemble flagella remains largely unknown. Here, we show that IFT of radial spokes in Chlamydomonas requires ARMC2/PF27, a conserved armadillo repeat protein associated with male infertility and reduced lung function. Chlamydomonas ARMC2 was highly enriched in growing flagella and tagged ARMC2 and the spoke protein RSP3 co-migrated on anterograde trains. In contrast, a cargo and an adapter of inner and outer dynein arms moved independently of ARMC2, indicating that unrelated cargoes distribute stochastically onto the IFT trains. After concomitant unloading at the flagellar tip, RSP3 attached to the axoneme whereas ARMC2 diffused back to the cell body. In armc2/pf27 mutants, IFT of radial spokes was abolished and the presence of radial spokes was limited to the proximal region of flagella. We conclude that ARMC2 is a cargo adapter required for IFT of radial spokes to ensure their assembly along flagella. ARMC2 belongs to a growing class of cargo-specific adapters that enable flagellar transport of preassembled axonemal substructures by IFT.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Yi Liu
- Department of Biological Sciences, Marquette University, Milwaukee, United States
| | - Jin Dai
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Rama A Alkhofash
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Jack Butler
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Lea Alford
- Division of Natural Sciences,, Oglethorpe University, Atlanta, United States
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, United States
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Zhao Y, Pinskey J, Lin J, Yin W, Sears PR, Daniels LA, Zariwala MA, Knowles MR, Ostrowski LE, Nicastro D. Structural insights into the cause of human RSPH4A primary ciliary dyskinesia. Mol Biol Cell 2021; 32:1202-1209. [PMID: 33852348 PMCID: PMC8351563 DOI: 10.1091/mbc.e20-12-0806] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 03/25/2021] [Accepted: 04/06/2021] [Indexed: 11/30/2022] Open
Abstract
Cilia and flagella are evolutionarily conserved eukaryotic organelles involved in cell motility and signaling. In humans, mutations in Radial Spoke Head Component 4A (RSPH4A) can lead to primary ciliary dyskinesia (PCD), a life-shortening disease characterized by chronic respiratory tract infections, abnormal organ positioning, and infertility. Despite its importance for human health, the location of RSPH4A in human cilia has not been resolved, and the structural basis of RSPH4A-/- PCD remains elusive. Here, we present the native three-dimensional structure of RSPH4A-/- human respiratory cilia using samples collected noninvasively from a PCD patient. Using cryo-electron tomography (cryo-ET) and subtomogram averaging, we compared the structures of control and RSPH4A-/- cilia, revealing primary defects in two of the three radial spokes (RSs) within the axonemal repeat and secondary (heterogeneous) defects in the central pair complex. Similar to RSPH1-/- cilia, the radial spoke heads of RS1 and RS2, but not RS3, were missing in RSPH4A-/- cilia. However, RSPH4A-/- cilia also exhibited defects within the arch domains adjacent to the RS1 and RS2 heads, which were not observed with RSPH1 loss. Our results provide insight into the underlying structural basis for RSPH4A-/- PCD and highlight the benefits of applying cryo-ET directly to patient samples for molecular structure determination.
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Affiliation(s)
- Yanhe Zhao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Justine Pinskey
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jianfeng Lin
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Weining Yin
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
| | - Patrick R Sears
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
| | - Leigh A Daniels
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
- Department of Medicine
| | - Maimoona A Zariwala
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
- Department of Pathology and Laboratory Medicine, and
| | - Michael R Knowles
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
- Department of Medicine
| | - Lawrence E Ostrowski
- Marsico Lung Institute, University of North Carolina, Chapel Hill, NC 27599
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC 27599
| | - Daniela Nicastro
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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5
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Gui M, Ma M, Sze-Tu E, Wang X, Koh F, Zhong ED, Berger B, Davis JH, Dutcher SK, Zhang R, Brown A. Structures of radial spokes and associated complexes important for ciliary motility. Nat Struct Mol Biol 2021; 28:29-37. [PMID: 33318703 PMCID: PMC7855293 DOI: 10.1038/s41594-020-00530-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/28/2020] [Indexed: 12/20/2022]
Abstract
In motile cilia, a mechanoregulatory network is responsible for converting the action of thousands of dynein motors bound to doublet microtubules into a single propulsive waveform. Here, we use two complementary cryo-EM strategies to determine structures of the major mechanoregulators that bind ciliary doublet microtubules in Chlamydomonas reinhardtii. We determine structures of isolated radial spoke RS1 and the microtubule-bound RS1, RS2 and the nexin-dynein regulatory complex (N-DRC). From these structures, we identify and build atomic models for 30 proteins, including 23 radial-spoke subunits. We reveal how mechanoregulatory complexes dock to doublet microtubules with regular 96-nm periodicity and communicate with one another. Additionally, we observe a direct and dynamically coupled association between RS2 and the dynein motor inner dynein arm subform c (IDAc), providing a molecular basis for the control of motor activity by mechanical signals. These structures advance our understanding of the role of mechanoregulation in defining the ciliary waveform.
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Affiliation(s)
- Miao Gui
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Meisheng Ma
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Erica Sze-Tu
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Fujiet Koh
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Thermo Fisher Scientific, Eindhoven, Netherlands
| | - Ellen D Zhong
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Bonnie Berger
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joseph H Davis
- Computational and Systems Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St. Louis, MO, USA
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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Zhu L, Liu H, Chen Y, Yan X, Zhu X. Rsph9 is critical for ciliary radial spoke assembly and central pair microtubule stability. Biol Cell 2018; 111:29-38. [PMID: 30383886 DOI: 10.1111/boc.201800060] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/26/2018] [Accepted: 10/30/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND INFORMATION In the "9+2"-type motile cilia, radial spokes (RSs) protruded from the nine peripheral microtubule doublets surround and interact with the central pair (CP) apparatus to regulate ciliary beat. RSPH9 is the human homologue of the essential protozoan RS head protein Rsp9. Its mutations in human primary ciliary dyskinesia patients, however, cause CP loss in a small portion of airway cilia without affecting the ciliary localization of other head proteins. RESULTS We characterized mouse Rsph9 and investigated its function in ependymal motile cilia. Rsph9 was specifically expressed in mouse tissues containing motile cilia and upregulated during multiciliation. Its ciliary localization complied with its putative role as an RS subunit. Depletion of Rsph9 by RNAi in mouse ependymal cilia resulted in a near complete CP loss and altered the ciliary beat pattern from planar to rotational. Multiple RS proteins, including those in the head, were also markedly downregulated in the Rsph9-depleted cilia. CONCLUSION Rsph9 is essential for both the RS head assembly and the CP maintenance in mammalian ependymal cilia. SIGNIFICANCE Our results help to understand the assembly and functions of mammalian RS and pathology of RS-related ciliopathy.
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Affiliation(s)
- Lei Zhu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Hao Liu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Yawen Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Xiumin Yan
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
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8
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Lechtreck KF, Mengoni I, Okivie B, Hilderhoff KB. In vivo analyses of radial spoke transport, assembly, repair and maintenance. Cytoskeleton (Hoboken) 2018; 75:352-362. [PMID: 30070024 DOI: 10.1002/cm.21457] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 01/15/2023]
Abstract
Radial spokes (RSs) are multiprotein complexes that regulate dynein activity. In the cell body, RS proteins (RSPs) are present in a 12S precursor, which enters the flagella and converts into the axoneme-bound 20S spokes consisting of a head and stalk. To study RS dynamics in vivo, we expressed fluorescent protein (FP)-tagged versions of the head protein RSP4 and the stalk protein RSP3 to rescue the corresponding Chlamydomonas mutants pf1, lacking spoke heads, and pf14, lacking RSs entirely. RSP3 and RSP4 mostly co-migrated by intraflagellar transport (IFT). The transport was elevated during flagellar assembly and IFT of RSP4-FP depended on RSP3. To study RS assembly independently of ciliogenesis, strains expressing FP-tagged RSPs were mated to untagged cells with, without, or with partial RSs. Tagged RSPs were incorporated in a spotted fashion along wild-type-derived flagella indicating an exchange of RSs. During the repair of pf1-derived axonemes, RSP4-FP is added onto the preexisting spoke stalks with little exchange of RSP3. Thus, RSP3 and RSP4 are transported together but appear to separate inside flagella during the repair of RSs. The 12S RS precursor encompassing both proteins could represent a transport form to ensure stoichiometric delivery of RSPs into flagella by IFT.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | - Ilaria Mengoni
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | - Batare Okivie
- Department of Cellular Biology, University of Georgia, Athens, Georgia
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9
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CFAP70 Is a Novel Axoneme-Binding Protein That Localizes at the Base of the Outer Dynein Arm and Regulates Ciliary Motility. Cells 2018; 7:cells7090124. [PMID: 30158508 PMCID: PMC6162463 DOI: 10.3390/cells7090124] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/24/2018] [Accepted: 08/28/2018] [Indexed: 12/11/2022] Open
Abstract
In the present study, we characterized CFAP70, a candidate of cilia-related protein in mice. As this protein has a cluster of tetratricopeptide repeat (TPR) domains like many components of the intraflagellar transport (IFT) complex, we investigated the domain functions of particular interest in ciliary targeting and/or localization. RT-PCR and immunohistochemistry of various mouse tissues demonstrated the association of CFAP70 with motile cilia and flagella. A stepwise extraction of proteins from swine tracheal cilia showed that CFAP70 bound tightly to the ciliary axoneme. Fluorescence microscopy of the cultured ependyma expressing fragments of CFAP70 demonstrated that the N-terminus rather than the C-terminus with the TPR domains was more important for the ciliary localization. When CFAP70 was knocked down in cultured mouse ependyma, reductions in cilia beating frequency were observed. Consistent with these observations, a Chlamydomonas mutant lacking the CFAP70 homolog, FAP70, showed defects in outer dynein arm (ODA) activity and a reduction in flagellar motility. Cryo-electron tomography revealed that the N-terminus of FAP70 resided stably at the base of the ODA. These results demonstrated that CFAP70 is a novel regulatory component of the ODA in motile cilia and flagella, and that the N-terminus is important for its ciliary localization.
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10
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Kubo T, Hou Y, Cochran DA, Witman GB, Oda T. A microtubule-dynein tethering complex regulates the axonemal inner dynein f (I1). Mol Biol Cell 2018. [PMID: 29540525 PMCID: PMC5921573 DOI: 10.1091/mbc.e17-11-0689] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
FAP44 and FAP43/FAP244 form a complex that tethers the Inner dynein subspecies f to the microtubule in Chlamydomonas flagella. The tether complex regulates flagellar motility by restraining conformational change in the dynein motor. Motility of cilia/flagella is generated by a coordinated activity of thousands of dyneins. Inner dynein arms (IDAs) are particularly important for the formation of ciliary/flagellar waveforms, but the molecular mechanism of IDA regulation is poorly understood. Here we show using cryoelectron tomography and biochemical analyses of Chlamydomonas flagella that a conserved protein FAP44 forms a complex that tethers IDA f (I1 dynein) head domains to the A-tubule of the axonemal outer doublet microtubule. In wild-type flagella, IDA f showed little nucleotide-dependent movement except for a tilt in the f β head perpendicular to the microtubule-sliding direction. In the absence of the tether complex, however, addition of ATP and vanadate caused a large conformational change in the IDA f head domains, suggesting that the movement of IDA f is mechanically restricted by the tether complex. Motility defects in flagella missing the tether demonstrates the importance of the IDA f-tether interaction in the regulation of ciliary/flagellar beating.
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Affiliation(s)
- Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Deborah A Cochran
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
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11
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Kubo T, Oda T. Electrostatic interaction between polyglutamylated tubulin and the nexin-dynein regulatory complex regulates flagellar motility. Mol Biol Cell 2017. [PMID: 28637765 PMCID: PMC5555654 DOI: 10.1091/mbc.e17-05-0285] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The 3D localization of polyglutamylated tubulin in eukaryotic flagella is identified. Polyglutamylated tubulins are located on the interface between the microtubule and its cross-bridging structure, the N-DRC. Flagellar motility is regulated by electrostatic interaction between negatively charged tubulins and positively charged N-DRC. Tubulins undergo various posttranslational modifications. Among them, polyglutamylation is involved in the motility of eukaryotic flagella and the stability of the axonemal microtubules. However, it remains unclear where polyglutamylated tubulin localizes precisely within the axoneme and how tubulin polyglutamylation affects flagellar motility. In this study, we identified the three-dimensional localization of the polyglutamylated tubulin in Chlamydomonas flagella using antibody labeling and cryo–electron tomography. Polyglutamylated tubulins specifically located in close proximity to a microtubule-cross-bridging structure called the nexin–dynein regulatory complex (N-DRC). Because N-DRC is positively charged, we hypothesized that there is an electrostatic interaction between the polyglutamylated tubulin and the N-DRC, and therefore we mutated the amino acid sequences of DRC4 to modify the charge of the N-DRC. We found that both augmentation and reduction of the positive charge on DRC4 resulted in reduced flagellar motility. Moreover, reduced motility in a mutant with a structurally defective N-DRC was partially restored by increasing the positive charge on DRC4. These results clearly indicate that beating motion of flagella is maintained by the electrostatic cross-bridge formed between the negatively charged polyglutamylated tubulins and the positively charged N-DRC.
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Affiliation(s)
- Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Yamanashi 409-3898, Japan
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12
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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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13
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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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14
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Oda T, Abe T, Yanagisawa H, Kikkawa M. Docking complex-independent alignment of outer dynein arms with 24-nm periodicity in vitro. J Cell Sci 2016; 129:1547-51. [DOI: 10.1242/jcs.184598] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/25/2016] [Indexed: 12/13/2022] Open
Abstract
The docking complex (DC) is a molecular complex necessary for assembly of outer dynein arms (ODAs) on the axonemal doublet microtubules (DMTs) in cilia and flagella. The DC is hypothesized to be a 24-nm molecular ruler because ODAs align along the DMTs with 24-nm periodicity. In this study, we rigorously tested this hypothesis using structural and genetic methods. We found that the ODAs could bind to DMTs and porcine microtubules with 24-nm periodicities even in the absence of DC in vitro. Using cryo-electron tomography and structural labeling, we observed that the DC took an unexpectedly flexible conformation and did not lie along the length of DMTs. In the absence of DC, ODAs were released from the DMT at relatively low ionic strength, suggesting that DC strengthens the electrostatic interactions between the ODA and DMT. Based on these results, we concluded that the DC serves as a flexible stabilizer of the ODA rather than a molecular ruler.
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Affiliation(s)
- Toshiyuki Oda
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan
- Department of Anatomy and Structural Biology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 1110 Shimokatoh, Chuo, Yamanashi, 409-3898, Japan
| | - Tatsuki Abe
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo, 113-0033, Japan
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15
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Urbanska P, Song K, Joachimiak E, Krzemien-Ojak L, Koprowski P, Hennessey T, Jerka-Dziadosz M, Fabczak H, Gaertig J, Nicastro D, Wloga D. The CSC proteins FAP61 and FAP251 build the basal substructures of radial spoke 3 in cilia. Mol Biol Cell 2015; 26:1463-75. [PMID: 25694453 PMCID: PMC4395127 DOI: 10.1091/mbc.e14-11-1545] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/09/2015] [Indexed: 11/25/2022] Open
Abstract
Motile cilia have nine doublet microtubules, with hundreds of associated proteins that repeat in modules. Each module contains three radial spokes, which differ in their architecture, protein composition, and function. The conserved proteins FAP61 and FAP251 are crucial for the assembly and stable docking of RS3 and cilia motility. Dynein motors and regulatory complexes repeat every 96 nm along the length of motile cilia. Each repeat contains three radial spokes, RS1, RS2, and RS3, which transduct signals between the central microtubules and dynein arms. Each radial spoke has a distinct structure, but little is known about the mechanisms of assembly and function of the individual radial spokes. In Chlamydomonas, calmodulin and spoke-associated complex (CSC) is composed of FAP61, FAP91, and FAP251 and has been linked to the base of RS2 and RS3. We show that in Tetrahymena, loss of either FAP61 or FAP251 reduces cell swimming and affects the ciliary waveform and that RS3 is either missing or incomplete, whereas RS1 and RS2 are unaffected. Specifically, FAP251-null cilia lack an arch-like density at the RS3 base, whereas FAP61-null cilia lack an adjacent portion of the RS3 stem region. This suggests that the CSC proteins are crucial for stable and functional assembly of RS3 and that RS3 and the CSC are important for ciliary motility.
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Affiliation(s)
- Paulina Urbanska
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Kangkang Song
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Ewa Joachimiak
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland Department of Animal Physiology, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland
| | - Lucja Krzemien-Ojak
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Piotr Koprowski
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Todd Hennessey
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
| | - Maria Jerka-Dziadosz
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Hanna Fabczak
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| | - Daniela Nicastro
- Department of Biology and Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Dorota Wloga
- Department of Cell Biology, Nencki Institute of Experimental Biology PAS, 02-093 Warsaw, Poland
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16
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Cryo-electron tomography reveals ciliary defects underlying human RSPH1 primary ciliary dyskinesia. Nat Commun 2014; 5:5727. [PMID: 25473808 PMCID: PMC4267722 DOI: 10.1038/ncomms6727] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/30/2014] [Indexed: 12/21/2022] Open
Abstract
Cilia play essential roles in normal human development and health; cilia dysfunction results in diseases such as primary ciliary dyskinesia (PCD). Despite their importance, the native structure of human cilia is unknown, and structural defects in the cilia of patients are often undetectable or remain elusive because of heterogeneity. Here we develop an approach that enables visualization of human (patient) cilia at high-resolution using cryo-electron tomography of samples obtained noninvasively by nasal scrape biopsy. We present the native 3D structures of normal and PCD-causing RSPH1-mutant human respiratory cilia in unprecedented detail; this allows comparisons of cilia structure across evolutionarily distant species and reveals the previously unknown primary defect and the heterogeneous secondary defects in RSPH1-mutant cilia. Our data provide evidence for structural and functional heterogeneity in radial spokes, suggest a mechanism for the milder RSPH1 PCD phenotype and demonstrate that cryo-electron tomography can be applied to human disease by directly imaging patient samples.
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Abstract
In recent decades, cilia have moved from relative obscurity to a position of importance for understanding multiple complex human diseases. Now termed the ciliopathies, these diseases inflict devastating effects on millions of people worldwide. In this review, written primarily for teachers and students who may not yet be aware of the recent exciting developments in this field, we provide a general overview of our current understanding of cilia and human disease. We start with an introduction to cilia structure and assembly and indicate where they are found in the human body. We then discuss the clinical features of selected ciliopathies, with an emphasis on primary ciliary dyskinesia, polycystic kidney disease, and retinal degeneration. The history of ciliopathy research involves a fascinating interplay between basic and clinical sciences, highlighted in a timeline. Finally, we summarize the relative strengths of individual model organisms for ciliopathy research; many of these are suitable for classroom use.
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Affiliation(s)
- Jason M Brown
- George B. Witman ( ) is a professor of cell and developmental biology and the George F. Booth Chair in Basic Sciences at the University of Massachusetts Medical School. Jason M. Brown trained as a postdoctoral fellow with GBW and is an assistant professor of biology at Salem State University, in Salem, Massachusetts
| | - George B Witman
- George B. Witman ( ) is a professor of cell and developmental biology and the George F. Booth Chair in Basic Sciences at the University of Massachusetts Medical School. Jason M. Brown trained as a postdoctoral fellow with GBW and is an assistant professor of biology at Salem State University, in Salem, Massachusetts
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18
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Oda T, Yanagisawa H, Kikkawa M. Detailed structural and biochemical characterization of the nexin-dynein regulatory complex. Mol Biol Cell 2014; 26:294-304. [PMID: 25411337 PMCID: PMC4294676 DOI: 10.1091/mbc.e14-09-1367] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The nexin-dynein regulatory complex (N-DRC) is a microtubule-cross-bridging structure in cilia/flagella. The precise 3D positions of N-DRC subunits are identified using cryo–electron tomography and structural labeling. The N-DRC is purified and its composition and microtubule-binding properties were characterized. The nexin-dynein regulatory complex (N-DRC) forms a cross-bridge between the outer doublet microtubules of the axoneme and regulates dynein motor activity in cilia/flagella. Although the molecular composition and the three-dimensional structure of N-DRC have been studied using mutant strains lacking N-DRC subunits, more accurate approaches are necessary to characterize the structure and function of N-DRC. In this study, we precisely localized DRC1, DRC2, and DRC4 using cryo–electron tomography and structural labeling. All three N-DRC subunits had elongated conformations and spanned the length of N-DRC. Furthermore, we purified N-DRC and characterized its microtubule-binding properties. Purified N-DRC bound to the microtubule and partially inhibited microtubule sliding driven by the outer dynein arms (ODAs). Of interest, microtubule sliding was observed even in the presence of fourfold molar excess of N-DRC relative to ODA. These results provide insights into the role of N-DRC in generating the beating motions of cilia/flagella.
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Affiliation(s)
- Toshiyuki Oda
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo Bunkyo-ku, Tokyo 113-0033, Japan
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19
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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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20
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Nakazawa Y, Ariyoshi T, Noga A, Kamiya R, Hirono M. Space-dependent formation of central pair microtubules and their interactions with radial spokes. PLoS One 2014; 9:e110513. [PMID: 25333940 PMCID: PMC4204893 DOI: 10.1371/journal.pone.0110513] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 09/20/2014] [Indexed: 02/01/2023] Open
Abstract
Cilia and flagella contain nine outer doublet microtubules and a pair of central microtubules. The central pair of microtubules (CP) is important for cilia/flagella beating, as clearly shown by primary ciliary dyskinesia resulting from the loss of the CP. The CP is thought to regulate axonemal dyneins through interaction with radial spokes (RSs). However, the nature of the CP-RS interaction is poorly understood. Here we examine the appearance of CPs in the axonemes of a Chlamydomonas mutant, bld12, which produces axonemes with 8 to 11 outer-doublets. Most of its 8-doublet axonemes lack CPs. However, in the double mutant of bld12 and pf14, a mutant lacking the RS, most 8-doublet axonemes contain the CP. Thus formation of the CP apparently depends on the internal space limited by the outer doublets and RSs. In 10- or 11-doublet axonemes, only 3–5 RSs are attached to the CP and the doublet arrangement is distorted most likely because the RSs attached to the CP pull the outer doublets toward the axonemal center. The CP orientation in the axonemes varies in double mutants formed between bld12 and mutants lacking particular CP projections. The mutant bld12 thus provides the first direct and visual information about the CP-RS interaction, as well as about the mechanism of CP formation.
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Affiliation(s)
- Yuki Nakazawa
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tetsuro Ariyoshi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Akira Noga
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Ritsu Kamiya
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo, Japan
| | - Masafumi Hirono
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
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21
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Exploiting genomic data to identify proteins involved in abalone reproduction. J Proteomics 2014; 108:337-53. [DOI: 10.1016/j.jprot.2014.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/30/2014] [Accepted: 06/02/2014] [Indexed: 01/31/2023]
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Abstract
Trypanosoma brucei is a pathogenic unicellular eukaryote that infects humans and other mammals in sub-Saharan Africa. A central feature of trypanosome biology is the single flagellum of the parasite, which is an essential and multifunctional organelle that facilitates cell propulsion, controls cell morphogenesis and directs cytokinesis. Moreover, the flagellar membrane is a specialized subdomain of the cell surface that mediates attachment to host tissues and harbours multiple virulence factors. In this Review, we discuss the structure, assembly and function of the trypanosome flagellum, including canonical roles in cell motility as well as novel and emerging roles in cell morphogenesis and host-parasite interactions.
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Affiliation(s)
- Gerasimos Langousis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095
| | - Kent L. Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095
- Molecular Biology Institute, University of California, Los Angeles, CA90095
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23
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Oda T, Yanagisawa H, Yagi T, Kikkawa M. Mechanosignaling between central apparatus and radial spokes controls axonemal dynein activity. ACTA ACUST UNITED AC 2014; 204:807-19. [PMID: 24590175 PMCID: PMC3941055 DOI: 10.1083/jcb.201312014] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nonspecific intermolecular collision between the central pair apparatus and radial spokes underlies a mechanosensing mechanism that regulates dynein activity in Chlamydomonas flagella. Cilia/flagella are conserved organelles that generate fluid flow in eukaryotes. The bending motion of flagella requires concerted activity of dynein motors. Although it has been reported that the central pair apparatus (CP) and radial spokes (RSs) are important for flagellar motility, the molecular mechanism underlying CP- and RS-mediated dynein regulation has not been identified. In this paper, we identified nonspecific intermolecular collision between CP and RS as one of the regulatory mechanisms for flagellar motility. By combining cryoelectron tomography and motility analyses of Chlamydomonasreinhardtii flagella, we show that binding of streptavidin to RS heads paralyzed flagella. Moreover, the motility defect in a CP projection mutant could be rescued by the addition of exogenous protein tags on RS heads. Genetic experiments demonstrated that outer dynein arms are the major downstream effectors of CP- and RS-mediated regulation of flagellar motility. These results suggest that mechanosignaling between CP and RS regulates dynein activity in eukaryotic flagella.
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Affiliation(s)
- Toshiyuki Oda
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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24
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Bush A, Hogg C. Primary ciliary dyskinesia: recent advances in epidemiology, diagnosis, management and relationship with the expanding spectrum of ciliopathy. Expert Rev Respir Med 2014; 6:663-82. [DOI: 10.1586/ers.12.60] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Dutcher SK. The awesome power of dikaryons for studying flagella and basal bodies in Chlamydomonas reinhardtii. Cytoskeleton (Hoboken) 2013; 71:79-94. [PMID: 24272949 DOI: 10.1002/cm.21157] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/19/2013] [Indexed: 11/08/2022]
Abstract
Cilia/flagella and basal bodies/centrioles play key roles in human health and homeostasis. Among the organisms used to study these microtubule-based organelles, the green alga Chlamydomonas reinhardtii has several advantages. One is the existence of a temporary phase of the life cycle, termed the dikaryon. These cells are formed during mating when the cells fuse and the behavior of flagella from two genetically distinguishable parents can be observed. During this stage, the cytoplasms mix allowing for a defect in the flagella of one parent to be rescued by proteins from the other parent. This offers the unique advantage of adding back wild-type gene product or labeled protein at endogenous levels that can used to monitor various flagellar and basal body phenotypes. Mutants that show rescue and ones that fail to show rescue are both informative about the nature of the flagella and basal body defects. When rescue occurs, it can be used to determine the mutant gene product and to follow the temporal and spatial patterns of flagellar assembly. This review describes many examples of insights into basal body and flagellar proteins' function and assembly that have been discovered using dikaryons and discusses the potential for further analyses.
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Affiliation(s)
- Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
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26
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Meng D, Cao M, Oda T, Pan J. The conserved ciliary protein Bug22 controls planar beating of Chlamydomonas flagella. J Cell Sci 2013; 127:281-7. [PMID: 24259666 DOI: 10.1242/jcs.140723] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic flagella and cilia can exhibit planar and non-planar beating, and the mechanism controlling these beating patterns is not well understood. Chlamydomonas reinhardtii flagella beat in approximately the same plane with either an asymmetric ciliary-type or symmetric flagellar-type waveform. Each B-tubule of the number 1, 5 and 6 doublets of the flagellar axoneme possesses a beak-like structure. The number 5 and 6 beak structures are implicated in conversion of ciliary motion into flagellar motion. Here, we show that in a null mutant of Bug22, the asymmetric ciliary waveform is converted into a three-dimensional (non-planar) symmetric flagellar waveform. Bug22 is localized to approximately the proximal half to two-thirds of the flagellum, similar to localization of beak-like structures. However, as shown by immunogold labeling, Bug22 associates with axonemal microtubules without apparent preference for any particular doublets. Interestingly, bug22 mutants lack all beak-like structures. We propose that one function of Bug22 is to regulate the anchoring of the beak-like structures to the doublet microtubules and confine flagellar beating to a plane.
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Affiliation(s)
- Dan Meng
- MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084, China
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27
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Lin H, Nauman NP, Albee AJ, Hsu S, Dutcher SK. New mutations in flagellar motors identified by whole genome sequencing in Chlamydomonas. Cilia 2013; 2:14. [PMID: 24229452 PMCID: PMC4132587 DOI: 10.1186/2046-2530-2-14] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 10/02/2013] [Indexed: 02/01/2023] Open
Abstract
Background The building of a cilium or flagellum requires molecular motors and associated
proteins that allow the relocation of proteins from the cell body to the distal
end and the return of proteins to the cell body in a process termed intraflagellar
transport (IFT). IFT trains are carried out by kinesin and back to the cell body
by dynein. Methods We used whole genome sequencing to identify the causative mutations for two
temperature-sensitive flagellar assembly mutants in Chlamydomonas and
validated the changes using reversion analysis. We examined the effect of these
mutations on the localization of IFT81, an IFT complex B protein, the cytoplasmic
dynein heavy chain (DHC1b), and the dynein light intermediate chain (D1bLIC). Results The strains, fla18 and fla24, have mutations in kinesin-2 and
cytoplasmic dynein, respectively. The fla18 mutation alters the same
glutamic acid (E24G) mutated in the fla10-14 allele
(E24K). The fla18 strain loses flagella at 32?C more
rapidly than the E24K allele but less rapidly than the fla10-1
allele. The fla18 mutant loses its flagella by detachment rather than by
shortening. The fla24 mutation falls in cytoplasmic dynein and changes a
completely conserved amino acid (L3243P) in an alpha helix in the AAA5
domain. The fla24 mutant loses its flagella by shortening within 6 hours
at 32?C. DHC1b protein is reduced by 18-fold and D1bLIC is reduced by 16-fold at
21?C compared to wild-type cells. We identified two pseudorevertants
(L3243S and L3243R), which remain flagellated at 32?C.
Although fla24 cells assemble full-length flagella at 21?C, IFT81 protein
localization is dramatically altered. Instead of localizing at the basal body and
along the flagella, IFT81 is concentrated at the proximal end of the flagella. The
pseudorevertants show wild-type IFT81 localization at 21?C, but proximal end
localization of IFT81 at 32?C. Conclusions The change in the AAA5 domain of the cytoplasmic dynein in fla24 may
block the recycling of IFT trains after retrograde transport. It is clear that
different alleles in the flagellar motors reveal different functions and roles.
Multiple alleles will be important for understanding structure-function
relationships.
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Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University, 660 South Euclid Avenue, St Louis, MO 63110, USA.
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28
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Diniz MC, Pacheco ACL, Farias KM, de Oliveira DM. The eukaryotic flagellum makes the day: novel and unforeseen roles uncovered after post-genomics and proteomics data. Curr Protein Pept Sci 2013; 13:524-46. [PMID: 22708495 PMCID: PMC3499766 DOI: 10.2174/138920312803582951] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 05/22/2012] [Accepted: 05/23/2012] [Indexed: 12/21/2022]
Abstract
This review will summarize and discuss the current biological understanding of the motile eukaryotic flagellum,
as posed out by recent advances enabled by post-genomics and proteomics approaches. The organelle, which is crucial
for motility, survival, differentiation, reproduction, division and feeding, among other activities, of many eukaryotes,
is a great example of a natural nanomachine assembled mostly by proteins (around 350-650 of them) that have been conserved
throughout eukaryotic evolution. Flagellar proteins are discussed in terms of their arrangement on to the axoneme,
the canonical “9+2” microtubule pattern, and also motor and sensorial elements that have been detected by recent proteomic
analyses in organisms such as Chlamydomonas reinhardtii, sea urchin, and trypanosomatids. Such findings can be
remarkably matched up to important discoveries in vertebrate and mammalian types as diverse as sperm cells, ciliated
kidney epithelia, respiratory and oviductal cilia, and neuro-epithelia, among others. Here we will focus on some exciting
work regarding eukaryotic flagellar proteins, particularly using the flagellar proteome of C. reinhardtii as a reference map
for exploring motility in function, dysfunction and pathogenic flagellates. The reference map for the eukaryotic flagellar
proteome consists of 652 proteins that include known structural and intraflagellar transport (IFT) proteins, less well-characterized
signal transduction proteins and flagellar associated proteins (FAPs), besides almost two hundred unannotated
conserved proteins, which lately have been the subject of intense investigation and of our present examination.
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Affiliation(s)
- Michely C Diniz
- Programa de Pós-Graduação em Biotecnologia-RENORBIO-Rede Nordeste de Biotecnologia, Universidade Estadual do Ceará-UECE, Av. Paranjana, 1700, Campus do Itaperi, Fortaleza, CE 60740-000 Brasil
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29
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Kott E, Legendre M, Copin B, Papon JF, Dastot-Le Moal F, Montantin G, Duquesnoy P, Piterboth W, Amram D, Bassinet L, Beucher J, Beydon N, Deneuville E, Houdouin V, Journel H, Just J, Nathan N, Tamalet A, Collot N, Jeanson L, Le Gouez M, Vallette B, Vojtek AM, Epaud R, Coste A, Clement A, Housset B, Louis B, Escudier E, Amselem S. Loss-of-function mutations in RSPH1 cause primary ciliary dyskinesia with central-complex and radial-spoke defects. Am J Hum Genet 2013; 93:561-70. [PMID: 23993197 DOI: 10.1016/j.ajhg.2013.07.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/09/2013] [Accepted: 07/16/2013] [Indexed: 12/22/2022] Open
Abstract
Primary ciliary dyskinesia (PCD) is a rare autosomal-recessive respiratory disorder resulting from defects of motile cilia. Various axonemal ultrastructural phenotypes have been observed, including one with so-called central-complex (CC) defects, whose molecular basis remains unexplained in most cases. To identify genes involved in this phenotype, whose diagnosis can be particularly difficult to establish, we combined homozygosity mapping and whole-exome sequencing in a consanguineous individual with CC defects. This identified a nonsense mutation in RSPH1, a gene whose ortholog in Chlamydomonas reinhardtii encodes a radial-spoke (RS)-head protein and is mainly expressed in respiratory and testis cells. Subsequent analyses of RSPH1 identified biallelic mutations in 10 of 48 independent families affected by CC defects. These mutations include splicing defects, as demonstrated by the study of RSPH1 transcripts obtained from airway cells of affected individuals. Wild-type RSPH1 localizes within cilia of airway cells, but we were unable to detect it in an individual with RSPH1 loss-of-function mutations. High-speed-videomicroscopy analyses revealed the coexistence of different ciliary beating patterns-cilia with a normal beat frequency but abnormal motion alongside immotile cilia or cilia with a slowed beat frequency-in each individual. This study shows that this gene is mutated in 20.8% of individuals with CC defects, whose diagnosis could now be improved by molecular screening. RSPH1 mutations thus appear as a major etiology for this PCD phenotype, which in fact includes RS defects, thereby unveiling the importance of RSPH1 in the proper building of CCs and RSs in humans.
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Affiliation(s)
- Esther Kott
- INSERM/UMR S933, Université Pierre et Marie Curie-Paris 6, Paris, France
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Horani A, Brody SL, Ferkol TW, Shoseyov D, Wasserman MG, Ta-shma A, Wilson KS, Bayly PV, Amirav I, Cohen-Cymberknoh M, Dutcher SK, Elpeleg O, Kerem E. CCDC65 mutation causes primary ciliary dyskinesia with normal ultrastructure and hyperkinetic cilia. PLoS One 2013; 8:e72299. [PMID: 23991085 PMCID: PMC3753302 DOI: 10.1371/journal.pone.0072299] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 07/08/2013] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Primary ciliary dyskinesia (PCD) is a genetic disorder characterized by impaired ciliary function, leading to chronic sinopulmonary disease. The genetic causes of PCD are still evolving, while the diagnosis is often dependent on finding a ciliary ultrastructural abnormality and immotile cilia. Here we report a novel gene associated with PCD but without ciliary ultrastructural abnormalities evident by transmission electron microscopy, but with dyskinetic cilia beating. METHODS Genetic linkage analysis was performed in a family with a PCD subject. Gene expression was studied in Chlamydomonas reinhardtii and human airway epithelial cells, using RNA assays and immunostaining. The phenotypic effects of candidate gene mutations were determined in primary culture human tracheobronchial epithelial cells transduced with gene targeted shRNA sequences. Video-microscopy was used to evaluate cilia motion. RESULTS A single novel mutation in CCDC65, which created a termination codon at position 293, was identified in a subject with typical clinical features of PCD. CCDC65, an orthologue of the Chlamydomonas nexin-dynein regulatory complex protein DRC2, was localized to the cilia of normal nasal epithelial cells but was absent in those from the proband. CCDC65 expression was up-regulated during ciliogenesis in cultured airway epithelial cells, as was DRC2 in C. reinhardtii following deflagellation. Nasal epithelial cells from the affected individual and CCDC65-specific shRNA transduced normal airway epithelial cells had stiff and dyskinetic cilia beating patterns compared to control cells. Moreover, Gas8, a nexin-dynein regulatory complex component previously identified to associate with CCDC65, was absent in airway cells from the PCD subject and CCDC65-silenced cells. CONCLUSION Mutation in CCDC65, a nexin-dynein regulatory complex member, resulted in a frameshift mutation and PCD. The affected individual had altered cilia beating patterns, and no detectable ultrastructural defects of the ciliary axoneme, emphasizing the role of the nexin-dynein regulatory complex and the limitations of certain methods for PCD diagnosis.
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Affiliation(s)
- Amjad Horani
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA.
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Horani A, Druley TE, Zariwala MA, Patel AC, Levinson BT, Van Arendonk LG, Thornton KC, Giacalone JC, Albee AJ, Wilson KS, Turner EH, Nickerson DA, Shendure J, Bayly PV, Leigh MW, Knowles MR, Brody SL, Dutcher SK, Ferkol TW. Whole-exome capture and sequencing identifies HEATR2 mutation as a cause of primary ciliary dyskinesia. Am J Hum Genet 2012; 91:685-93. [PMID: 23040496 DOI: 10.1016/j.ajhg.2012.08.022] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Revised: 08/05/2012] [Accepted: 08/24/2012] [Indexed: 01/23/2023] Open
Abstract
Motile cilia are essential components of the mucociliary escalator and are central to respiratory-tract host defenses. Abnormalities in these evolutionarily conserved organelles cause primary ciliary dyskinesia (PCD). Despite recent strides characterizing the ciliome and sensory ciliopathies through exploration of the phenotype-genotype associations in model organisms, the genetic bases of most cases of PCD remain elusive. We identified nine related subjects with PCD from geographically dispersed Amish communities and performed exome sequencing of two affected individuals and their unaffected parents. A single autosomal-recessive nonsynonymous missense mutation was identified in HEATR2, an uncharacterized gene that belongs to a family not previously associated with ciliary assembly or function. Airway epithelial cells isolated from PCD-affected individuals had markedly reduced HEATR2 levels, absent dynein arms, and loss of ciliary beating. MicroRNA-mediated silencing of the orthologous gene in Chlamydomonas reinhardtii resulted in absent outer dynein arms, reduced flagellar beat frequency, and decreased cell velocity. These findings were recapitulated by small hairpin RNA-mediated knockdown of HEATR2 in airway epithelial cells from unaffected donors. Moreover, immunohistochemistry studies in human airway epithelial cells showed that HEATR2 was localized to the cytoplasm and not in cilia, which suggests a role in either dynein arm transport or assembly. The identification of HEATR2 contributes to the growing number of genes associated with PCD identified in both individuals and model organisms and shows that exome sequencing in family studies facilitates the discovery of novel disease-causing gene mutations.
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Affiliation(s)
- Amjad Horani
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110, USA
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Burgoyne T, Dixon M, Luther P, Hogg C, Shoemark A. Generation of a three-dimensional ultrastructural model of human respiratory cilia. Am J Respir Cell Mol Biol 2012; 47:800-6. [PMID: 22936404 DOI: 10.1165/rcmb.2011-0440oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The ultrastructures of cilia and flagella are highly similar and well conserved through evolution. Consequently, Chlamydomonas is commonly used as a model organism for the study of human respiratory cilia. Since detailed models of Chlamydomonas axonemes were generated using cryoelectron tomography, disparities among some of the ultrastructural features have become apparent when compared with human cilia. Extrapolating information on human disease from the Chlamydomonas model may lead to discrepancies in translational research. This study aimed to establish the first three-dimensional ultrastructural model of human cilia. Tomograms of transverse sections (n = 6) and longitudinal sections (n = 9) of human nasal respiratory cilia were generated from three healthy volunteers. Key features of the cilium were resolved using subatomic averaging, and were measured. For validation of the method, a model of the well characterized structure of Chlamydomonas reinhardtii was simultaneously generated. Data were combined to create a fully quantified three-dimensional reconstruction of human nasal respiratory cilia. We highlight key differences in the axonemal sheath, microtubular doublets, radial spokes, and dynein arms between the two structures. We show a decreased axial periodicity of the radial spokes, inner dynein arms, and central pair protrusions in the human model. We propose that this first human model will provide a basis for research into the function and structure of human respiratory cilia in health and in disease.
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Affiliation(s)
- Thomas Burgoyne
- Electron Microscopy Unit, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
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Abstract
Eukaryotic cilia/flagella are ancient organelles with motility and sensory functions. Cilia display significant ultrastructural conservation where present across the eukaryotic phylogeny; however, diversity in ciliary biology exists and the ability to produce cilia has been lost independently on a number of occasions. Land plants provide an excellent system for the investigation of cilia evolution and loss across a broad phylogeny, because early divergent land plant lineages produce cilia, whereas most seed plants do not. This review highlights the differences in cilia form and function across land plants and discusses how recent advances in genomics are providing novel insights into the evolutionary trajectory of ciliary proteins. We propose a renewed effort to adopt ciliated land plants as models to investigate the mechanisms underpinning complex ciliary processes, such as number control, the coordination of basal body placement and the regulation of beat patterns.
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Affiliation(s)
- Matthew E Hodges
- Department of Plant Sciences, South Parks Road, University of Oxford, Oxford OX1 3RB, UK
| | - Bill Wickstead
- Centre for Genetics and Genomics, University of Nottingham, Nottingham NG7 2UH, UK
| | - Keith Gull
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford OX1 3RE, UK
| | - Jane A Langdale
- Department of Plant Sciences, South Parks Road, University of Oxford, Oxford OX1 3RB, UK
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Heuser T, Dymek EE, Lin J, Smith EF, Nicastro D. The CSC connects three major axonemal complexes involved in dynein regulation. Mol Biol Cell 2012; 23:3143-55. [PMID: 22740634 PMCID: PMC3418309 DOI: 10.1091/mbc.e12-05-0357] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This study reveals the 3D structure of the CSC and its connections to three major axonemal complexes involved in dynein regulation, including the distal radial spoke and the nexin-DRC. The findings corroborate radial spoke heterogeneity and suggest a unique role for the distal spoke in calcium-mediated signal transduction and flagellar motility. Motile cilia and flagella are highly conserved organelles that play important roles in human health and development. We recently discovered a calmodulin- and spoke-associated complex (CSC) that is required for wild-type motility and for the stable assembly of a subset of radial spokes. Using cryo–electron tomography, we present the first structure-based localization model of the CSC. Chlamydomonas flagella have two full-length radial spokes, RS1 and RS2, and a shorter RS3 homologue, the RS3 stand-in (RS3S). Using newly developed techniques for analyzing samples with structural heterogeneity, we demonstrate that the CSC connects three major axonemal complexes involved in dynein regulation: RS2, the nexin–dynein regulatory complex (N-DRC), and RS3S. These results provide insights into how signals from the radial spokes may be transmitted to the N-DRC and ultimately to the dynein motors. Our results also indicate that although structurally very similar, RS1 and RS2 likely serve different functions in regulating flagellar motility.
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Affiliation(s)
- Thomas Heuser
- Biology Department, Rosenstiel Center, Brandeis University, Waltham, MA 02454, USA
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Lin J, Heuser T, Carbajal-González BI, Song K, Nicastro D. The structural heterogeneity of radial spokes in cilia and flagella is conserved. Cytoskeleton (Hoboken) 2012; 69:88-100. [PMID: 22170736 DOI: 10.1002/cm.21000] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/02/2011] [Accepted: 12/05/2011] [Indexed: 01/05/2023]
Abstract
Radial spokes (RSs) are ubiquitous components of motile cilia and flagella and play an essential role in transmitting signals that regulate the activity of the dynein motors, and thus ciliary and flagellar motility. In some organisms, the 96 nm axonemal repeat unit contains only a pair of spokes, RS1 and RS2, while most organisms have spoke triplets with an additional spoke RS3. The spoke pairs in Chlamydomonas flagella have been well characterized, while spoke triplets have received less attention. Here, we used cryoelectron tomography and subtomogram averaging to visualize the three-dimensional structure of spoke triplets in Strongylocentrotus purpuratus (sea urchin) sperm flagella in unprecedented detail. Only small differences were observed between RS1 and RS2, but the structure of RS3 was surprisingly unique and structurally different from the other two spokes. We observed novel doublet specific features that connect RS2, RS3, and the nexin-dynein regulatory complex, three key ciliary and flagellar structures. The distribution of these doublet specific structures suggests that they could be important for establishing the asymmetry of dynein activity required for the oscillatory movement of cilia and flagella. Surprisingly, a comparison with other organisms demonstrated both that this considerable RS heterogeneity is conserved and that organisms with RS pairs contain the basal part of RS3. This conserved RS heterogeneity may also reflect functional differences between the spokes and their involvement in regulating ciliary and flagellar motility.
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Affiliation(s)
- Jianfeng Lin
- Department of Biology, Rosenstiel Center, MS029, Brandeis University, Waltham, Massachusetts 02454-9110, USA
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36
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Diener DR, Yang P, Geimer S, Cole DG, Sale WS, Rosenbaum JL. Sequential assembly of flagellar radial spokes. Cytoskeleton (Hoboken) 2011; 68:389-400. [PMID: 21692193 DOI: 10.1002/cm.20520] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The unicellular alga Chlamydomonas can assemble two 10 μm flagella in 1 h from proteins synthesized in the cell body. Targeting and transporting these proteins to the flagella are simplified by preassembly of macromolecular complexes in the cell body. Radial spokes are flagellar complexes that are partially assembled in the cell body before entering the flagella. On the axoneme, radial spokes are "T" shaped structures with a head of five proteins and a stalk of 18 proteins that sediment together at 20S. In the cell body, radial spokes are partially assembled; about half of the radial spoke proteins (RSPs) form a 12S complex. In mutants lacking a single RSP, smaller spoke subassemblies were identified. When extracts from two such mutants were mixed in vitro the 12S complex was assembled from several smaller complexes demonstrating that portions of the stepwise assembly of radial spoke assembly can be carried out in vitro to elucidate the order of spoke assembly in the cell body.
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Affiliation(s)
- Dennis R Diener
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA
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37
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Barber CF, Heuser T, Carbajal-González BI, Botchkarev VV, Nicastro D. Three-dimensional structure of the radial spokes reveals heterogeneity and interactions with dyneins in Chlamydomonas flagella. Mol Biol Cell 2011; 23:111-20. [PMID: 22072792 PMCID: PMC3248890 DOI: 10.1091/mbc.e11-08-0692] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cryo–electron tomography of Chlamydomonas flagella reveals previously uncharacterized features of the radial spokes, including structural heterogeneity and direct interactions with dyneins and between the spoke heads. A “radial spoke 3 stand-in” occupies what would be the site of a third spoke in organisms with spoke triplets. Radial spokes (RSs) play an essential role in the regulation of axonemal dynein activity and thus of ciliary and flagellar motility. However, few details are known about the complexes involved. Using cryo–electron tomography and subtomogram averaging, we visualized the three-dimensional structure of the radial spokes in Chlamydomonas flagella in unprecedented detail. Unlike many other species, Chlamydomonas has only two spokes per axonemal repeat, RS1 and RS2. Our data revealed previously uncharacterized features, including two-pronged spoke bases that facilitate docking to the doublet microtubules, and that inner dyneins connect directly to the spokes. Structures of wild type and the headless spoke mutant pf17 were compared to define the morphology and boundaries of the head, including a direct RS1-to-RS2 interaction. Although the overall structures of the spokes are very similar, we also observed some differences, corroborating recent findings about heterogeneity in the docking of RS1 and RS2. In place of a third radial spoke we found an uncharacterized, shorter electron density named “radial spoke 3 stand-in,” which structurally bears no resemblance to RS1 and RS2 and is unaltered in the pf17 mutant. These findings demonstrate that radial spokes are heterogeneous in structure and may play functionally distinct roles in axoneme regulation.
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Affiliation(s)
- Cynthia F Barber
- Biology Department, Rosenstiel Center, Brandeis University, Waltham, MA 02454, USA
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38
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Pigino G, Bui KH, Maheshwari A, Lupetti P, Diener D, Ishikawa T. Cryoelectron tomography of radial spokes in cilia and flagella. ACTA ACUST UNITED AC 2011; 195:673-87. [PMID: 22065640 PMCID: PMC3257535 DOI: 10.1083/jcb.201106125] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cryo-EM tomography of wild-type and mutant cilia and flagella from Tetrahymena and Chlamydomonas reveals new information on the substructure of radial spokes. Radial spokes (RSs) are ubiquitous components in the 9 + 2 axoneme thought to be mechanochemical transducers involved in local control of dynein-driven microtubule sliding. They are composed of >23 polypeptides, whose interactions and placement must be deciphered to understand RS function. In this paper, we show the detailed three-dimensional (3D) structure of RS in situ in Chlamydomonas reinhardtii flagella and Tetrahymena thermophila cilia that we obtained using cryoelectron tomography (cryo-ET). We clarify similarities and differences between the three spoke species, RS1, RS2, and RS3, in T. thermophila and in C. reinhardtii and show that part of RS3 is conserved in C. reinhardtii, which only has two species of complete RSs. By analyzing C. reinhardtii mutants, we identified the specific location of subsets of RS proteins (RSPs). Our 3D reconstructions show a twofold symmetry, suggesting that fully assembled RSs are produced by dimerization. Based on our cryo-ET data, we propose models of subdomain organization within the RS as well as interactions between RSPs and with other axonemal components.
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Affiliation(s)
- Gaia Pigino
- Biomolecular Research Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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39
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Satir P, Dirksen ER. Function‐Structure Correlations in Cilia from Mammalian Respiratory Tract. Compr Physiol 2011. [DOI: 10.1002/cphy.cp030115] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Wei M, Sivadas P, Owen HA, Mitchell DR, Yang P. Chlamydomonas mutants display reversible deficiencies in flagellar beating and axonemal assembly. Cytoskeleton (Hoboken) 2010; 67:71-80. [PMID: 20169531 PMCID: PMC2835312 DOI: 10.1002/cm.20422] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 10/14/2009] [Indexed: 11/12/2022]
Abstract
Axonemal complexes in flagella are largely prepackaged in the cell body. As such, one mutation often results in the absence of the co-assembled components and permanent motility deficiencies. For example, a Chlamydomonas mutant defective in RSP4 in the radial spoke (RS), which is critical for bend propagation, has paralyzed flagella that also lack the paralogue RSP6 and three additional RS proteins. Intriguingly, recent studies showed that several mutant strains contain a mixed population of swimmers and paralyzed cells despite their identical genetic background. Here we report a cause underlying these variations. Two new mutants lacking RSP6 swim processively and other components appear normally assembled in early log phase indicating that, unlike RSP4, this paralogue is dispensable. However, swimmers cannot maintain the typical helical trajectory and reactivated cell models tend to spin. Interestingly the motile fraction and the spokehead content dwindle during stationary phase. These results suggest that (1) intact RS is critical for maintaining the rhythm of oscillatory beating and thus the helical trajectory; (2) assembly of the axonemal complex with subtle defects is less efficient and the inefficiency is accentuated in compromised conditions, leading to reversible dyskinesia. Consistently, several organisms only possess one RSP4/6 gene. Gene duplication in Chlamydomonas enhances RS assembly to maintain optimal motility in various environments.
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Affiliation(s)
- Mei Wei
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
| | - Priyanka Sivadas
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
| | - Heather A. Owen
- Department of Biological Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211
| | - David R. Mitchell
- Department of Cell and Developmental Biology, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
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Abstract
The 9+2 axoneme that mediates the highly controlled oscillatory beating of cilia and flagella is an elaborate supramolecular complex. Proteomics and genomics have revealed more than 400 distinct polypeptides that presumably are built into axonemal subcomplexes for specific tasks. However, only a handful of proteins can be assigned to the most prominent structural modules visible by electron microscopy. Much less is known about the function and mechanism of individual molecules and complexes. Isolation of intact complexes will hasten discoveries and open the door to a wide range of analyses as showcased by axonemal dynein motors. However, many axonemal components, such as the radial spoke complex, either are not extracted by conditions that solubilize axonemal dynein or at best are only partially released. This chapter discusses strategies and methods to circumvent this problem in order to characterize radial spokes. With appropriate modifications, the lessons learned from the radial spoke complex may be applicable to other axonemal complexes.
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Leigh MW, Pittman JE, Carson JL, Ferkol TW, Dell SD, Davis SD, Knowles MR, Zariwala MA. Clinical and genetic aspects of primary ciliary dyskinesia/Kartagener syndrome. Genet Med 2009; 11:473-87. [PMID: 19606528 PMCID: PMC3739704 DOI: 10.1097/gim.0b013e3181a53562] [Citation(s) in RCA: 274] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Primary ciliary dyskinesia is a genetically heterogeneous disorder of motile cilia. Most of the disease-causing mutations identified to date involve the heavy (dynein axonemal heavy chain 5) or intermediate(dynein axonemal intermediate chain 1) chain dynein genes in ciliary outer dynein arms, although a few mutations have been noted in other genes. Clinical molecular genetic testing for primary ciliary dyskinesia is available for the most common mutations. The respiratory manifestations of primary ciliary dyskinesia (chronic bronchitis leading to bronchiectasis, chronic rhino-sinusitis, and chronic otitis media)reflect impaired mucociliary clearance owing to defective axonemal structure. Ciliary ultrastructural analysis in most patients (>80%) reveals defective dynein arms, although defects in other axonemal components have also been observed. Approximately 50% of patients with primary ciliary dyskinesia have laterality defects (including situs inversus totalis and, less commonly, heterotaxy, and congenital heart disease),reflecting dysfunction of embryological nodal cilia. Male infertility is common and reflects defects in sperm tail axonemes. Most patients with primary ciliary dyskinesia have a history of neonatal respiratory distress, suggesting that motile cilia play a role in fluid clearance during the transition from a fetal to neonatal lung. Ciliopathies involving sensory cilia, including autosomal dominant or recessive polycystic kidney disease, Bardet-Biedl syndrome, and Alstrom syndrome, may have chronic respiratory symptoms and even bronchiectasis suggesting clinical overlap with primary ciliary dyskinesia.
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Affiliation(s)
- Margaret W. Leigh
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Jessica E. Pittman
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Johnny L. Carson
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Thomas W. Ferkol
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA
| | - Sharon D. Dell
- Child Health Evaluative Sciences, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stephanie D. Davis
- Department of Pediatrics, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Michael R. Knowles
- Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Maimoona A. Zariwala
- Department of Pathology/Lab Medicine, University of North Carolina School of Medicine, Chapel Hill, NC, USA
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Portman N, Lacomble S, Thomas B, McKean PG, Gull K. Combining RNA interference mutants and comparative proteomics to identify protein components and dependences in a eukaryotic flagellum. J Biol Chem 2009; 284:5610-9. [PMID: 19074134 PMCID: PMC2645819 DOI: 10.1074/jbc.m808859200] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Indexed: 01/23/2023] Open
Abstract
Eukaryotic flagella from organisms such as Trypanosoma brucei can be isolated and their protein components identified by mass spectrometry. Here we used a comparative approach utilizing two-dimensional difference gel electrophoresis and isobaric tags for relative and absolute quantitation to reveal protein components of flagellar structures via ablation by inducible RNA interference mutation. By this approach we identified 20 novel components of the paraflagellar rod (PFR). Using epitope tagging we validated a subset of these as being present within the PFR by immunofluorescence. Bioinformatic analysis of the PFR cohort reveals a likely calcium/calmodulin regulatory/signaling linkage between some components. We extended the RNA interference mutant/comparative proteomic analysis to individual novel components of our PFR proteome, showing that the approach has the power to reveal dependences between subgroups within the cohort.
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MESH Headings
- Animals
- Cells, Cultured
- Chromatography, Liquid
- DNA, Protozoan/genetics
- DNA, Protozoan/metabolism
- Electrophoresis, Gel, Two-Dimensional
- Flagella/genetics
- Flagella/metabolism
- Fluorescent Antibody Technique
- Proteomics
- Protozoan Proteins/antagonists & inhibitors
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
- RNA Interference
- RNA, Protozoan/genetics
- RNA, Protozoan/metabolism
- RNA, Small Interfering/pharmacology
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
- Trypanosoma brucei brucei/genetics
- Trypanosoma brucei brucei/metabolism
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Affiliation(s)
- Neil Portman
- Sir William Dunn School of Pathology and Oxford Centre for Integrative Systems Biology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom
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Rajagopalan V, Subramanian A, Wilkes DE, Pennock DG, Asai DJ. Dynein-2 affects the regulation of ciliary length but is not required for ciliogenesis in Tetrahymena thermophila. Mol Biol Cell 2009; 20:708-20. [PMID: 19019986 PMCID: PMC2626569 DOI: 10.1091/mbc.e08-07-0746] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 10/28/2008] [Accepted: 11/07/2008] [Indexed: 11/11/2022] Open
Abstract
Eukaryotic cilia and flagella are assembled and maintained by the bidirectional intraflagellar transport (IFT). Studies in alga, nematode, and mouse have shown that the heavy chain (Dyh2) and the light intermediate chain (D2LIC) of the cytoplasmic dynein-2 complex are essential for retrograde intraflagellar transport. In these organisms, disruption of either dynein-2 component results in short cilia/flagella with bulbous tips in which excess IFT particles have accumulated. In Tetrahymena, the expression of the DYH2 and D2LIC genes increases during reciliation, consistent with their roles in IFT. However, the targeted elimination of either DYH2 or D2LIC gene resulted in only a mild phenotype. Both knockout cell lines assembled motile cilia, but the cilia were of more variable lengths and less numerous than wild-type controls. Electron microscopy revealed normally shaped cilia with no swelling and no obvious accumulations of material in the distal ciliary tip. These results demonstrate that dynein-2 contributes to the regulation of ciliary length but is not required for ciliogenesis in Tetrahymena.
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Affiliation(s)
| | | | - David E. Wilkes
- *Department of Biology, Harvey Mudd College, Claremont, CA 91711
| | | | - David J. Asai
- *Department of Biology, Harvey Mudd College, Claremont, CA 91711
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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Abstract
In unicellular and multicellular eukaryotes, fast cell motility and rapid movement of material over cell surfaces are often mediated by ciliary or flagellar beating. The conserved defining structure in most motile cilia and flagella is the '9+2' microtubule axoneme. Our general understanding of flagellum assembly and the regulation of flagellar motility has been led by results from seminal studies of flagellate protozoa and algae. Here we review recent work relating to various aspects of protist physiology and cell biology. In particular, we discuss energy metabolism in eukaryotic flagella, modifications to the canonical assembly pathway and flagellum function in parasite virulence.
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Vucica Y, Diener DR, Rosenbaum JL, Koutoulis A. Ultrastructural and biochemical analysis of a new mutation in Chlamydomonas reinhardtii affecting the central pair apparatus. PROTOPLASMA 2007; 232:121-130. [PMID: 18157500 DOI: 10.1007/s00709-007-0273-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 04/19/2007] [Indexed: 05/25/2023]
Abstract
We present a new Chlamydomonas reinhardtii flagellar mutant in which central pair projections are missing and the central pair microtubules are twisted along the length of the flagellum. We have named this mutant tcp1 for twisted central pair. Immunoblots using an antibody that recognizes the heavy chain of sea urchin kinesin reveal that a 70 kDa protein present in wild-type and pf18 (central pairless) axonemes is absent in tcp1, suggesting the presence of an uncharacterized kinesin associated with the central pair apparatus. We demonstrate that the kinesin-like protein Klp1 is not attached to central pair microtubules in tcp1, but rather is located in, or is part of, a region we have termed the internal axonemal matrix. It is proposed that this matrix acts as a scaffold for axonemal proteins that may also be associated with the central pair apparatus.
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Affiliation(s)
- Y Vucica
- Cell Biology Group, School of Plant Science, University of Tasmania, Hobart, Tasmania, Australia
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Abstract
Cilia, hair-like structures extending from the cell membrane, perform diverse biological functions. Primary (genetic) defects in the structure and function of sensory and motile cilia result in multiple ciliopathies. The most prominent genetic abnormality involving motile cilia (and the respiratory tract) is primary ciliary dyskinesia (PCD). PCD is a rare, usually autosomal recessive, genetically heterogeneous disorder characterized by sino-pulmonary disease, laterality defects, and male infertility. Ciliary ultrastructural defects are identified in approximately 90% of PCD patients and involve the outer dynein arms, inner dynein arms, or both. Diagnosing PCD is challenging and requires a compatible clinical phenotype together with tests such as ciliary ultrastructural analysis, immunofluorescent staining, ciliary beat assessment, and/or nasal nitric oxide measurements. Recent mutational analysis demonstrated that 38% of PCD patients carry mutations of the dynein genes DNAI1 and DNAH5. Increased understanding of the pathogenesis will aid in better diagnosis and treatment of PCD.
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Affiliation(s)
- Maimoona A Zariwala
- Department of Medicine, Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
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Zariwala MA, Leigh MW, Ceppa F, Kennedy MP, Noone PG, Carson JL, Hazucha MJ, Lori A, Horvath J, Olbrich H, Loges NT, Bridoux AM, Pennarun G, Duriez B, Escudier E, Mitchison HM, Chodhari R, Chung EMK, Morgan LC, de Iongh RU, Rutland J, Pradal U, Omran H, Amselem S, Knowles MR. Mutations of DNAI1 in primary ciliary dyskinesia: evidence of founder effect in a common mutation. Am J Respir Crit Care Med 2006. [PMID: 16858015 DOI: 10.1164/rccm.200603-370oc.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Primary ciliary dyskinesia (PCD) is a rare, usually autosomal recessive, genetic disorder characterized by ciliary dysfunction, sino-pulmonary disease, and situs inversus. Disease-causing mutations have been reported in DNAI1 and DNAH5 encoding outer dynein arm (ODA) proteins of cilia. OBJECTIVES We analyzed DNAI1 to identify disease-causing mutations in PCD and to determine if the previously reported IVS1+2_3insT (219+3insT) mutation represents a "founder" or "hot spot" mutation. METHODS Patients with PCD from 179 unrelated families were studied. Exclusion mapping showed no linkage to DNAI1 for 13 families; the entire coding region was sequenced in a patient from the remaining 166 families. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed on nasal epithelial RNA in 14 families. RESULTS Mutations in DNAI1 including 12 novel mutations were identified in 16 of 179 (9%) families; 14 harbored biallelic mutations. Deep intronic splice mutations were not identified by reverse transcriptase-polymerase chain reaction. The prevalence of mutations in families with defined ODA defect was 13%; no mutations were found in patients without a defined ODA defect. The previously reported IVS1+2_3insT mutation accounted for 57% (17/30) of mutant alleles, and marker analysis indicates a common founder for this mutation. Seven mutations occurred in three exons (13, 16, and 17); taken together with previous reports, these three exons are emerging as mutation clusters harboring 29% (12/42) of mutant alleles. CONCLUSIONS A total of 10% of patients with PCD are estimated to harbor mutations in DNAI1; most occur as a common founder IVS1+2_3insT or in exons 13, 16, and 17. This information is useful for establishing a clinical molecular genetic test for PCD.
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Affiliation(s)
- Maimoona A Zariwala
- University of North Carolina at Chapel Hill 27599-7248, USA, and Department of Pediatrics and Adolescent Medicine, University Hospital Freiburg, Germany.
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Förster B, Mathesius U, Pogson BJ. Comparative proteomics of high light stress in the model algaChlamydomonas reinhardtii. Proteomics 2006; 6:4309-20. [PMID: 16800035 DOI: 10.1002/pmic.200500907] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
High light (HL) stress adversely affects growth, productivity and viability of photosynthetic organisms. The green alga Chlamydomonas reinhardtii is a model system to study photosynthesis and light stress. Comparative proteomics of wild-type and two very high light (VHL)-resistant mutants, VHL(R)-S4 and VHL(R)-S9, revealed complex alterations in response to excess light. A two-dimensional reference map of the soluble subproteome was constructed representing about 1500 proteins. A total of 83 proteins from various metabolic pathways were identified by peptide mass fingerprinting. Quantitative comparisons of 444 proteins showed 105 significantly changed proteins between wild type and mutants under different light conditions. Commonly, more proteins were decreased than increased, but different proteins were affected in each genotype. Proteins uniquely altered in either VHL(R) mutant may be involved in VHL resistance. Such candidate proteins similarly altered without light stress, thus possibly contributing to "pre-adaptation" of mutants to VHL, included decreased levels of a DEAD box RNA helicase (VHL(R)-S4) and NAB1 and RB38 proteins (VHL(R)-S9), and increased levels of an oxygen evolving enhancer 1 (OEE1) isoform and an unknown protein (VHL(R)-S4). Changes from increased levels in HL to decreased levels in excess light, included OEE1 (VHL(R)-S9) or the reverse change for NAB1, RB38, beta-carbonic anhydrase and an ABC transporter-like protein (VHL(R)-S4).
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Affiliation(s)
- Britta Förster
- ARC Centre of Excellence in Plant Energy Biology, School of Biochemistry and Molecular Biology, The Australian National University, Canberra, Australia
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