1
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Lindemann CB, Lesich KA. The mechanics of cilia and flagella: What we know and what we need to know. Cytoskeleton (Hoboken) 2024. [PMID: 38780123 DOI: 10.1002/cm.21879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 05/25/2024]
Abstract
In this review, we provide a condensed overview of what is currently known about the mechanical functioning of the flagellar/ciliary axoneme. We also present a list of 10 specific areas where our current knowledge is incomplete and explain the benefits of further experimental investigation. Many of the physical parameters of the axoneme and its component parts have not been determined. This limits our ability to understand how the axoneme structure contributes to its functioning in several regards. It restricts our ability to understand how the mechanics of the structure contribute to the regulation of motor function. It also confines our ability to understand the three-dimensional workings of the axoneme and how various beating modes are accomplished. Lastly, it prevents accurate computational modeling of the axoneme in three-dimensions.
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Affiliation(s)
- Charles B Lindemann
- Department of Biological Sciences, Oakland University, Rochester, Michigan, USA
| | - Kathleen A Lesich
- Department of Biological Sciences, Oakland University, Rochester, Michigan, USA
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2
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Chen Z, Greenan GA, Shiozaki M, Liu Y, Skinner WM, Zhao X, Zhao S, Yan R, Yu Z, Lishko PV, Agard DA, Vale RD. In situ cryo-electron tomography reveals the asymmetric architecture of mammalian sperm axonemes. Nat Struct Mol Biol 2023; 30:360-369. [PMID: 36593309 PMCID: PMC10023559 DOI: 10.1038/s41594-022-00861-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/11/2022] [Indexed: 01/04/2023]
Abstract
The flagella of mammalian sperm display non-planar, asymmetric beating, in contrast to the planar, symmetric beating of flagella from sea urchin sperm and unicellular organisms. The molecular basis of this difference is unclear. Here, we perform in situ cryo-electron tomography of mouse and human sperm, providing the highest-resolution structural information to date. Our subtomogram averages reveal mammalian sperm-specific protein complexes within the microtubules, the radial spokes and nexin-dynein regulatory complexes. The locations and structures of these complexes suggest potential roles in enhancing the mechanical strength of mammalian sperm axonemes and regulating dynein-based axonemal bending. Intriguingly, we find that each of the nine outer microtubule doublets is decorated with a distinct combination of sperm-specific complexes. We propose that this asymmetric distribution of proteins differentially regulates the sliding of each microtubule doublet and may underlie the asymmetric beating of mammalian sperm.
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Affiliation(s)
- Zhen Chen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Garrett A Greenan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Momoko Shiozaki
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yanxin Liu
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Will M Skinner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Xiaowei Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Shumei Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Rui Yan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Zhiheng Yu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Polina V Lishko
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Center for Reproductive Longevity and Equality, Buck Institute for Research on Aging, Novato, CA, USA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
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3
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Towards an atomic model of a beating ciliary axoneme. Curr Opin Struct Biol 2023; 78:102516. [PMID: 36586349 DOI: 10.1016/j.sbi.2022.102516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/15/2022] [Accepted: 11/23/2022] [Indexed: 12/30/2022]
Abstract
The axoneme of motile cilia and eukaryotic flagella is an ordered assembly of hundreds of proteins that powers the locomotion of single cells and generates flow of liquid and particles across certain mammalian tissues. The symmetric and organized structure of the axoneme has invited structural biologists to unravel its intricate architecture at different scales. In the last few years, single-particle cryo-electron microscopy provided high-resolution structures of axonemal complexes that comprise dozens of proteins and are key to cilia function. This review summarizes unique structural features of the axoneme and the framework they provide to understand cilia assembly, the mechanism of ciliary beating, and clinical conditions associated with impaired cilia motility.
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4
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Ciliary central apparatus structure reveals mechanisms of microtubule patterning. Nat Struct Mol Biol 2022; 29:483-492. [PMID: 35578023 PMCID: PMC9930914 DOI: 10.1038/s41594-022-00770-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/30/2022] [Indexed: 02/05/2023]
Abstract
A pair of extensively modified microtubules form the central apparatus (CA) of the axoneme of most motile cilia, where they regulate ciliary motility. The external surfaces of both CA microtubules are patterned asymmetrically with large protein complexes that repeat every 16 or 32 nm. The composition of these projections and the mechanisms that establish asymmetry and longitudinal periodicity are unknown. Here, by determining cryo-EM structures of the CA microtubules, we identify 48 different CA-associated proteins, which in turn reveal mechanisms for asymmetric and periodic protein binding to microtubules. We identify arc-MIPs, a novel class of microtubule inner protein, that bind laterally across protofilaments and remodel tubulin structure and lattice contacts. The binding mechanisms utilized by CA proteins may be generalizable to other microtubule-associated proteins. These structures establish a foundation to elucidate the contributions of individual CA proteins to ciliary motility and ciliopathies.
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5
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Han L, Rao Q, Yang R, Wang Y, Chai P, Xiong Y, Zhang K. Cryo-EM structure of an active central apparatus. Nat Struct Mol Biol 2022; 29:472-482. [PMID: 35578022 PMCID: PMC9113940 DOI: 10.1038/s41594-022-00769-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/30/2022] [Indexed: 12/13/2022]
Abstract
Accurately regulated ciliary beating in time and space is critical for diverse cellular activities, which impact the survival and development of nearly all eukaryotic species. An essential beating regulator is the conserved central apparatus (CA) of motile cilia, composed of a pair of microtubules (C1 and C2) associated with hundreds of protein subunits per repeating unit. It is largely unclear how the CA plays its regulatory roles in ciliary motility. Here, we present high-resolution structures of Chlamydomonas reinhardtii CA by cryo-electron microscopy (cryo-EM) and its dynamic conformational behavior at multiple scales. The structures show how functionally related projection proteins of CA are clustered onto a spring-shaped scaffold of armadillo-repeat proteins, facilitated by elongated rachis-like proteins. The two halves of the CA are brought together by elastic chain-like bridge proteins to achieve coordinated activities. We captured an array of kinesin-like protein (KLP1) in two different stepping states, which are actively correlated with beating wave propagation of cilia. These findings establish a structural framework for understanding the role of the CA in cilia.
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Affiliation(s)
- Long Han
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Qinhui Rao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Renbin Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Center for Molecular Microscopy, Frederick National Laboratory for Cancer Research, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, USA
| | - Yue Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Pengxin Chai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Yong Xiong
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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6
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Abstract
Cilia are tail-like organelles responsible for motility, transportation, and sensory functions in eukaryotic cells. Cilia research has been providing multifaceted questions, attracting biologists of various areas and inducing interdisciplinary studies. In this chapter, we mainly focus on efforts to elucidate the molecular mechanism of ciliary beating motion, a field of research that has a long history and is still ongoing. We also overview topics closely related to the motility mechanism, such as ciliogenesis, cilia-related diseases, and sensory cilia. Subnanometer-scale to submillimeter-scale 3D imaging of the axoneme and the basal body resulted in a wide variety of insights into these questions.
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Affiliation(s)
- Takashi Ishikawa
- Department of Biology and Chemistry, Paul Scherrer Institute, Villigen, Switzerland.
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7
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Teng XJ, Ng WM, Chong WH, Chan DJC, Mohamud R, Ooi BS, Guo C, Liu C, Lim J. The Transport Behavior of a Biflagellated Microswimmer before and after Cargo Loading. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:9192-9201. [PMID: 34255525 DOI: 10.1021/acs.langmuir.1c01345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The changes in the transport behavior of a microswimmer before and after cargo loading are crucial to understanding and control of the motion of a biohybrid microbot. In this work, we show the change in swimming behavior of biflagellated microalgae Chlamydomonas reinhardtii picking up a 4.5 μm polystyrene microbead upon collision. The microswimmer changed from linear forward motion into helical motion upon the attachment of the cargo and swam with a decreased swimming velocity. We revealed the helical motion of the microswimmer upon cargo loading due to suppression of flagella by image analysis of magnified time-lapse images of C. reinhardtii with one microbead attached at the anterior end (between the flagella). Furthered suppression on the flagellum imposed by the loading of the second cargo has led to increased oscillation per displacement traveled and decreased swimming velocity. Moreover, the microswimmer with a microbead attached at the posterior end swam with swimming velocity close to free swimming microalgae and did not exhibit helical swimming behavior. The experimental results and analysis showed that the loading location of the cargo has a great influence over the swimming behavior of the microswimmer. Furthermore, the work balance calculation and mathematical analysis based on Lighthill's model are well consistent with our experimental findings.
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Affiliation(s)
- Xiau Jeong Teng
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
| | - Wei Ming Ng
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
| | - Wai Hong Chong
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
| | - Derek Juinn Chieh Chan
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
| | - Rohimah Mohamud
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, 16150 Kelantan, Malaysia
| | - Boon Seng Ooi
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
| | - Chen Guo
- State Key Laboratory of Biochemical Engineering & Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Chunzhao Liu
- State Key Laboratory of Biochemical Engineering & Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- State Key Laboratory of Bio-fibers and Eco-textiles, Institute of Biochemical Engineering, Affiliated Qingdao Central Hospital, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, P.R. China
| | - JitKang Lim
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, 14300 Penang, Malaysia
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Unites States
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8
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Gong A, Rode S, Gompper G, Kaupp UB, Elgeti J, Friedrich BM, Alvarez L. Reconstruction of the three-dimensional beat pattern underlying swimming behaviors of sperm. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:87. [PMID: 34196906 PMCID: PMC8249298 DOI: 10.1140/epje/s10189-021-00076-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/06/2021] [Indexed: 05/09/2023]
Abstract
The eukaryotic flagellum propels sperm cells and simultaneously detects physical and chemical cues that modulate the waveform of the flagellar beat. Most previous studies have characterized the flagellar beat and swimming trajectories in two space dimensions (2D) at a water/glass interface. Here, using refined holographic imaging methods, we report high-quality recordings of three-dimensional (3D) flagellar bending waves. As predicted by theory, we observed that an asymmetric and planar flagellar beat results in a circular swimming path, whereas a symmetric and non-planar flagellar beat results in a twisted-ribbon swimming path. During swimming in 3D, human sperm flagella exhibit torsion waves characterized by maxima at the low curvature regions of the flagellar wave. We suggest that these torsion waves are common in nature and that they are an intrinsic property of beating axonemes. We discuss how 3D beat patterns result in twisted-ribbon swimming paths. This study provides new insight into the axoneme dynamics, the 3D flagellar beat, and the resulting swimming behavior.
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Affiliation(s)
- A Gong
- Center of Advanced European Studies and Research (caesar), Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - S Rode
- Theoretical Physics of Living Matter, Institute of Biological Information Processing and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - G Gompper
- Theoretical Physics of Living Matter, Institute of Biological Information Processing and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - U B Kaupp
- Center of Advanced European Studies and Research (caesar), Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
| | - J Elgeti
- Theoretical Physics of Living Matter, Institute of Biological Information Processing and Institute for Advanced Simulation, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - B M Friedrich
- Biological Algorithms Group, TU Dresden, Cluster of Excellence 'Physics of Life' and Center for Advancing Electronics Dresden (cfaed), Helmholtzstr. 18, 01069, Dresden, Germany
| | - L Alvarez
- Center of Advanced European Studies and Research (caesar), Molecular Sensory Systems, Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
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9
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Hou Y, Zhao L, Kubo T, Cheng X, McNeill N, Oda T, Witman GB. Chlamydomonas FAP70 is a component of the previously uncharacterized ciliary central apparatus projection C2a. J Cell Sci 2021; 134:jcs258540. [PMID: 33988244 PMCID: PMC8272932 DOI: 10.1242/jcs.258540] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
Cilia are essential organelles required for cell signaling and motility. Nearly all motile cilia have a '9+2' axoneme composed of nine outer doublet microtubules plus two central microtubules; the central microtubules together with their projections are termed the central apparatus (CA). In Chlamydomonas reinhardtii, a model organism for studying cilia, 30 proteins are known CA components, and ∼36 more are predicted to be CA proteins. Among the candidate CA proteins is the highly conserved FAP70 (CFAP70 in humans), which also has been reported to be associated with the doublet microtubules. Here, we determined by super-resolution structured illumination microscopy that FAP70 is located exclusively in the CA, and show by cryo-electron microscopy that its N-terminus is located at the base of the C2a projection of the CA. We also found that fap70-1 mutant axonemes lack most of the C2a projection. Mass spectrometry revealed that fap70-1 axonemes lack not only FAP70 but two other conserved candidate CA proteins, FAP65 (CFAP65 in humans) and FAP147 (MYCBPAP in humans). Finally, FAP65 and FAP147 co-immunoprecipitated with HA-tagged FAP70. Taken together, these data identify FAP70, FAP65 and FAP147 as the first defining components of the C2a projection.
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Affiliation(s)
- Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Lei Zhao
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Xi Cheng
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Nathan McNeill
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - George B. Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
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10
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Central Apparatus, the Molecular Kickstarter of Ciliary and Flagellar Nanomachines. Int J Mol Sci 2021; 22:ijms22063013. [PMID: 33809498 PMCID: PMC7999657 DOI: 10.3390/ijms22063013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 02/07/2023] Open
Abstract
Motile cilia and homologous organelles, the flagella, are an early evolutionarily invention, enabling primitive eukaryotic cells to survive and reproduce. In animals, cilia have undergone functional and structural speciation giving raise to typical motile cilia, motile nodal cilia, and sensory immotile cilia. In contrast to other cilia types, typical motile cilia are able to beat in complex, two-phase movements. Moreover, they contain many additional structures, including central apparatus, composed of two single microtubules connected by a bridge-like structure and assembling numerous complexes called projections. A growing body of evidence supports the important role of the central apparatus in the generation and regulation of the motile cilia movement. Here we review data concerning the central apparatus structure, protein composition, and the significance of its components in ciliary beating regulation.
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11
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Dutcher SK. Asymmetries in the cilia of Chlamydomonas. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190153. [PMID: 31884924 PMCID: PMC7017335 DOI: 10.1098/rstb.2019.0153] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2019] [Indexed: 01/10/2023] Open
Abstract
The generation of ciliary waveforms requires the spatial and temporal regulation of dyneins. This review catalogues many of the asymmetric structures and proteins in the cilia of Chlamydomonas, a unicellular alga with two cilia that are used for motility in liquid medium. These asymmetries, which have been identified through mutant analysis, cryo-EM tomography and proteomics, provide a wealth of information to use for modelling how waveforms are generated and propagated. This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.
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Affiliation(s)
- Susan K. Dutcher
- Department of Genetics, Washington University in St Louis, Saint Louis, MO, USA
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12
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Intraflagellar transport 20: New target for the treatment of ciliopathies. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118641. [PMID: 31893523 DOI: 10.1016/j.bbamcr.2019.118641] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 12/17/2019] [Accepted: 12/25/2019] [Indexed: 11/22/2022]
Abstract
Cilia are ubiquitous in mammalian cells. The formation and assembly of cilia depend on the normal functioning of the ciliary transport system. In recent years, various proteins involved in the intracellular transport of the cilium have attracted attention, as many diseases are caused by disorders in cilia formation. Intraflagellar transport 20 (IFT20) is a subunit of IFT complex B, which contains approximately 20 protein particles. Studies have shown that defects in IFT20 are associated with numerous system -related diseases, such as those of the urinary system, cardiovascular system, skeletal system, nervous system, immune system, reproductive system, and respiratory system. This review summarizes current research on IFT20.We describe studies related to the role of IFT20 in cilia formation and discuss new targets for treating diseases associated with ciliary dysplasia.
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13
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Zhao L, Hou Y, Picariello T, Craige B, Witman GB. Proteome of the central apparatus of a ciliary axoneme. J Cell Biol 2019; 218:2051-2070. [PMID: 31092556 PMCID: PMC6548120 DOI: 10.1083/jcb.201902017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/13/2019] [Accepted: 04/17/2019] [Indexed: 12/15/2022] Open
Abstract
The central apparatus is an essential component of “9+2” cilia. Zhao et al. identify more than 40 new potential components of the central apparatus of Chlamydomonas. Many are conserved and will facilitate genetic screening of patients with a form of primary ciliary dyskinesia that is difficult to diagnose. Nearly all motile cilia have a “9+2” axoneme containing a central apparatus (CA), consisting of two central microtubules with projections, that is essential for motility. To date, only 22 proteins are known to be CA components. To identify new candidate CA proteins, we used mass spectrometry to compare axonemes of wild-type Chlamydomonas and a CA-less mutant. We identified 44 novel candidate CA proteins, of which 13 are conserved in humans. Five of the latter were studied more closely, and all five localized to the CA; therefore, most of the other candidates are likely to also be CA components. Our results reveal that the CA is far more compositionally complex than previously recognized and provide a greatly expanded knowledge base for studies to understand the architecture of the CA and how it functions. The discovery of the new conserved CA proteins will facilitate genetic screening to identify patients with a form of primary ciliary dyskinesia that has been difficult to diagnose.
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Affiliation(s)
- Lei Zhao
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Tyler Picariello
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Branch Craige
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
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14
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King SM. Turning dyneins off bends cilia. Cytoskeleton (Hoboken) 2018; 75:372-381. [PMID: 30176122 PMCID: PMC6249098 DOI: 10.1002/cm.21483] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 12/15/2022]
Abstract
Ciliary and flagellar motility is caused by the ensemble action of inner and outer dynein arm motors acting on axonemal doublet microtubules. The switch point or switching hypothesis, for which much experimental and computational evidence exists, requires that dyneins on only one side of the axoneme are actively working during bending, and that this active motor region propagate along the axonemal length. Generation of a reverse bend results from switching active sliding to the opposite side of the axoneme. However, the mechanochemical states of individual dynein arms within both straight and curved regions and how these change during beating has until now eluded experimental observation. Recently, Lin and Nicastro used high-resolution cryo-electron tomography to determine the power stroke state of dyneins along flagella of sea urchin sperm that were rapidly frozen while actively beating. The results reveal that axonemal dyneins are generally in a pre-power stroke conformation that is thought to yield a force-balanced state in straight regions; inhibition of this conformational state and microtubule release on specific doublets may then lead to a force imbalance across the axoneme allowing for microtubule sliding and consequently the initiation and formation of a ciliary bend. Propagation of this inhibitory signal from base-to-tip and switching the microtubule doublet subsets that are inhibited is proposed to result in oscillatory motion.
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Affiliation(s)
- Stephen M. King
- Department of Molecular Biology and BiophysicsUniversity of Connecticut Health CenterFarmingtonConnecticut
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15
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Reynolds MJ, Phetruen T, Fisher RL, Chen K, Pentecost BT, Gomez G, Ounjai P, Sui H. The Developmental Process of the Growing Motile Ciliary Tip Region. Sci Rep 2018; 8:7977. [PMID: 29789632 PMCID: PMC5964098 DOI: 10.1038/s41598-018-26111-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 05/01/2018] [Indexed: 11/09/2022] Open
Abstract
Eukaryotic motile cilia/flagella play vital roles in various physiological processes in mammals and some protists. Defects in cilia formation underlie multiple human disorders, known as ciliopathies. The detailed processes of cilia growth and development are still far from clear despite extensive studies. In this study, we characterized the process of cilium formation (ciliogenesis) by investigating the newly developed motile cilia of deciliated protists using complementary techniques in electron microscopy and image analysis. Our results demonstrated that the distal tip region of motile cilia exhibit progressive morphological changes as cilia develop. This developmental process is time-dependent and continues after growing cilia reach their full lengths. The structural analysis of growing ciliary tips revealed that B-tubules of axonemal microtubule doublets terminate far away from the tip end, which is led by the flagellar tip complex (FTC), demonstrating that the FTC might not directly mediate the fast turnover of intraflagellar transport (IFT).
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Affiliation(s)
- Matthew J Reynolds
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
- Biology Department, University of Scranton, Scranton, PA, 18510, USA
| | - Tanaporn Phetruen
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Rebecca L Fisher
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
| | - Ke Chen
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
| | - Brian T Pentecost
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA
| | - George Gomez
- Biology Department, University of Scranton, Scranton, PA, 18510, USA
| | - Puey Ounjai
- Department of Biology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Haixin Sui
- Wadsworth Center, New York State Department of Health, Albany, NY, 12201, USA.
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, 12201, USA.
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16
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Viswanadha R, Sale WS, Porter ME. Ciliary Motility: Regulation of Axonemal Dynein Motors. Cold Spring Harb Perspect Biol 2017; 9:9/8/a018325. [PMID: 28765157 DOI: 10.1101/cshperspect.a018325] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Ciliary motility is crucial for the development and health of many organisms. Motility depends on the coordinated activity of multiple dynein motors arranged in a precise pattern on the outer doublet microtubules. Although significant progress has been made in elucidating the composition and organization of the dyneins, a comprehensive understanding of dynein regulation is lacking. Here, we focus on two conserved signaling complexes located at the base of the radial spokes. These include the I1/f inner dynein arm associated with radial spoke 1 and the calmodulin- and spoke-associated complex and the nexin-dynein regulatory complex associated with radial spoke 2. Current research is focused on understanding how these two axonemal hubs coordinate and regulate the dynein motors and ciliary motility.
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Affiliation(s)
- Rasagnya Viswanadha
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Winfield S Sale
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Mary E Porter
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, Minnesota 55455
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17
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Loreng TD, Smith EF. The Central Apparatus of Cilia and Eukaryotic Flagella. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028118. [PMID: 27770014 DOI: 10.1101/cshperspect.a028118] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The motile cilium is a complex organelle that is typically comprised of a 9+2 microtubule skeleton; nine doublet microtubules surrounding a pair of central singlet microtubules. Like the doublet microtubules, the central microtubules form a scaffold for the assembly of protein complexes forming an intricate network of interconnected projections. The central microtubules and associated structures are collectively referred to as the central apparatus (CA). Studies using a variety of experimental approaches and model organisms have led to the discovery of a number of highly conserved protein complexes, unprecedented high-resolution views of projection structure, and new insights into regulation of dynein-driven microtubule sliding. Here, we review recent progress in defining mechanisms for the assembly and function of the CA and include possible implications for the importance of the CA in human health.
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Affiliation(s)
- Thomas D Loreng
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
| | - Elizabeth F Smith
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755
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18
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Abstract
Anton van Leeuwenhoek's startling microscopic observations in the 1600s first stimulated fascination with the way that cells use cilia to generate currents and to swim in a fluid environment. Research in recent decades has yielded deep knowledge about the mechanical and biochemical nature of these organelles but only opened a greater fascination about how such beautifully intricate and multifunctional structures arose during evolution. Answers to this evolutionary puzzle are not only sought to satisfy basic curiosity, but also, as stated so eloquently by Dobzhansky (Am Zool 4: 443 [1964]), because "nothing in biology makes sense except in the light of evolution." Here I attempt to summarize current knowledge of what ciliary organelles of the last eukaryotic common ancestor (LECA) were like, explore the ways in which cilia have evolved since that time, and speculate on the selective processes that might have generated these organelles during early eukaryotic evolution.
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Affiliation(s)
- David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York 13210
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19
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Abstract
The axoneme is the main extracellular part of cilia and flagella in eukaryotes. It consists of a microtubule cytoskeleton, which normally comprises nine doublets. In motile cilia, dynein ATPase motor proteins generate sliding motions between adjacent microtubules, which are integrated into a well-orchestrated beating or rotational motion. In primary cilia, there are a number of sensory proteins functioning on membranes surrounding the axoneme. In both cases, as the study of proteomics has elucidated, hundreds of proteins exist in this compartmentalized biomolecular system. In this article, we review the recent progress of structural studies of the axoneme and its components using electron microscopy and X-ray crystallography, mainly focusing on motile cilia. Structural biology presents snapshots (but not live imaging) of dynamic structural change and gives insights into the force generation mechanism of dynein, ciliary bending mechanism, ciliogenesis, and evolution of the axoneme.
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Affiliation(s)
- Takashi Ishikawa
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.,Department of Biology, ETH Zurich, 5232 Villigen PSI, Switzerland
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20
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Bayly PV, Dutcher SK. Steady dynein forces induce flutter instability and propagating waves in mathematical models of flagella. J R Soc Interface 2016; 13:20160523. [PMID: 27798276 PMCID: PMC5095214 DOI: 10.1098/rsif.2016.0523] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/26/2016] [Indexed: 12/26/2022] Open
Abstract
Cilia and flagella are highly conserved organelles that beat rhythmically with propulsive, oscillatory waveforms. The mechanism that produces these autonomous oscillations remains a mystery. It is widely believed that dynein activity must be dynamically regulated (switched on and off, or modulated) on opposite sides of the axoneme to produce oscillations. A variety of regulation mechanisms have been proposed based on feedback from mechanical deformation to dynein force. In this paper, we show that a much simpler interaction between dynein and the passive components of the axoneme can produce coordinated, propulsive oscillations. Steady, distributed axial forces, acting in opposite directions on coupled beams in viscous fluid, lead to dynamic structural instability and oscillatory, wave-like motion. This 'flutter' instability is a dynamic analogue to the well-known static instability, buckling. Flutter also occurs in slender beams subjected to tangential axial loads, in aircraft wings exposed to steady air flow and in flexible pipes conveying fluid. By analysis of the flagellar equations of motion and simulation of structural models of flagella, we demonstrate that dynein does not need to switch direction or inactivate to produce autonomous, propulsive oscillations, but must simply pull steadily above a critical threshold force.
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Affiliation(s)
- P V Bayly
- Department of Mechanical Engineering and Materials Science, 1 Brookings Drive, Box 1185, Saint Louis, MO 63130, USA
| | - S K Dutcher
- Department of Genetics, Washington University in Saint Louis, 1 Brookings Drive, Box 1185, Saint Louis, MO 63130, USA
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21
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Ishikawa T. Cryo-electron tomography of motile cilia and flagella. Cilia 2015; 4:3. [PMID: 25646146 PMCID: PMC4313461 DOI: 10.1186/s13630-014-0012-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 12/23/2014] [Indexed: 11/13/2022] Open
Abstract
Cryo-electron tomography has been a valuable tool in the analysis of 3D structures of cilia at molecular and cellular levels. It opened a way to reconstruct 3D conformations of proteins in cilia at 3-nm resolution, revealed networks of a number of component proteins in cilia, and has even allowed the study of component dynamics. In particular, we have identified the locations and conformations of all the regular inner and outer dyneins, as well as various regulators such as radial spokes. Since the mid 2000s, cryo-electron tomography has provided us with new knowledge, concepts, and questions in the area of cilia research. Now, after nearly 10 years of application of this technique, we are turning a corner and are at the stage to discuss the next steps. We expect further development of this technique for specimen preparation, data acquisition, and analysis. While combining this tool with other methodologies has already made cryo-electron tomography more biologically significant, we need to continue this cooperation using recently developed biotechnology and cell biology approaches. In this review, we will provide an up-to-date overview of the biological insights obtained by cryo-electron tomography and will discuss future possibilities of this technique in the context of cilia research.
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Affiliation(s)
- Takashi Ishikawa
- Group of Electron Microscopy of Complex Cellular System, Laboratory of Biomolecular Research, Paul Scherrer Institute, OFLG/010, 5232 Villigen PSI, Switzerland
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22
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Abstract
The motile cilium is a mechanical wonder, a cellular nanomachine that produces a high-speed beat based on a cycle of bends that move along an axoneme made of 9+2 microtubules. The molecular motors, dyneins, power the ciliary beat. The dyneins are compacted into inner and outer dynein arms, whose activity is highly regulated to produce microtubule sliding and axonemal bending. The switch point hypothesis was developed long ago to account for how sliding in the presence of axonemal radial spoke-central pair interactions causes the ciliary beat. Since then, a new genetic, biochemical, and structural complexity has been discovered, in part, with Chlamydomonas mutants, with high-speed, high-resolution analysis of movement and with cryoelectron tomography. We stand poised on the brink of new discoveries relating to the molecular control of motility that extend and refine our understanding of the basic events underlying the switching of arm activity and of bend formation and propagation.
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Affiliation(s)
- Peter Satir
- Peter Satir ( ) is affiliated with the Department of Anatomy and Structural Biology at Albert Einstein College of Medicine, in New York, New York. Thomas Heuser is affiliated with the Electron Microscopy Facility, in the Campus Science Support Facilities of the Campus Vienna Biocenter, in Vienna, Austria. Winfield S. Sale is affiliated with the Department of Cell Biology at Emory University, in Atlanta, Georgia
| | - Thomas Heuser
- Peter Satir ( ) is affiliated with the Department of Anatomy and Structural Biology at Albert Einstein College of Medicine, in New York, New York. Thomas Heuser is affiliated with the Electron Microscopy Facility, in the Campus Science Support Facilities of the Campus Vienna Biocenter, in Vienna, Austria. Winfield S. Sale is affiliated with the Department of Cell Biology at Emory University, in Atlanta, Georgia
| | - Winfield S Sale
- Peter Satir ( ) is affiliated with the Department of Anatomy and Structural Biology at Albert Einstein College of Medicine, in New York, New York. Thomas Heuser is affiliated with the Electron Microscopy Facility, in the Campus Science Support Facilities of the Campus Vienna Biocenter, in Vienna, Austria. Winfield S. Sale is affiliated with the Department of Cell Biology at Emory University, in Atlanta, Georgia
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23
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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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24
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Pigino G, Ishikawa T. Axonemal radial spokes: 3D structure, function and assembly. BIOARCHITECTURE 2014; 2:50-58. [PMID: 22754630 PMCID: PMC3383722 DOI: 10.4161/bioa.20394] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The radial spoke (RS) is a complex of at least 23 proteins that works as a mechanochemical transducer between the central‐pair apparatus and the peripheral microtubule doublets in eukaryotic flagella and motile cilia. The RS contributes to the regulation of the activity of dynein motors, and thus to flagellar motility. Despite numerous biochemical, physiological and structural studies, the mechanism of the function of the radial spoke remains unclear. Detailed knowledge of the 3D structure of the RS protein complex is needed in order to understand how RS regulates dynein activity. Here we review the most important findings on the structure of the RS, including results of our recent cryo‐electron tomographic analysis of the RS protein complex.
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25
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Abstract
In this issue, Oda et al. (2014. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201312014) use mutant analysis, protein tagging, and cryoelectron tomography to determine the detailed location of components in flagellar radial spokes-a complex of proteins that connect the peripheral microtubule doublets to the central pair. Remarkably, this approach revealed an interaction between radial spokes and the central pair based on geometry rather than a specific signaling mechanism, highlighting the importance of studying a system in three dimensions.
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Affiliation(s)
- Takashi Ishikawa
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
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26
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Onoufriadis A, Shoemark A, Schmidts M, Patel M, Jimenez G, Liu H, Thomas B, Dixon M, Hirst RA, Rutman A, Burgoyne T, Williams C, Scully J, Bolard F, Lafitte JJ, Beales PL, Hogg C, Yang P, Chung EMK, Emes RD, O'Callaghan C, Bouvagnet P, Mitchison HM. Targeted NGS gene panel identifies mutations in RSPH1 causing primary ciliary dyskinesia and a common mechanism for ciliary central pair agenesis due to radial spoke defects. Hum Mol Genet 2014; 23:3362-74. [PMID: 24518672 PMCID: PMC4049301 DOI: 10.1093/hmg/ddu046] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Primary ciliary dyskinesia (PCD) is an inherited chronic respiratory obstructive disease with randomized body laterality and infertility, resulting from cilia and sperm dysmotility. PCD is characterized by clinical variability and extensive genetic heterogeneity, associated with different cilia ultrastructural defects and mutations identified in >20 genes. Next generation sequencing (NGS) technologies therefore present a promising approach for genetic diagnosis which is not yet in routine use. We developed a targeted panel-based NGS pipeline to identify mutations by sequencing of selected candidate genes in 70 genetically undefined PCD patients. This detected loss-of-function RSPH1 mutations in four individuals with isolated central pair (CP) agenesis and normal body laterality, from two unrelated families. Ultrastructural analysis in RSPH1-mutated cilia revealed transposition of peripheral outer microtubules into the ‘empty’ CP space, accompanied by a distinctive intermittent loss of the central pair microtubules. We find that mutations in RSPH1, RSPH4A and RSPH9, which all encode homologs of components of the ‘head’ structure of ciliary radial spoke complexes identified in Chlamydomonas, cause clinical phenotypes that appear to be indistinguishable except at the gene level. By high-resolution immunofluorescence we identified a loss of RSPH4A and RSPH9 along with RSPH1 from RSPH1-mutated cilia, suggesting RSPH1 mutations may result in loss of the entire spoke head structure. CP loss is seen in up to 28% of PCD cases, in whom laterality determination specified by CP-less embryonic node cilia remains undisturbed. We propose this defect could arise from instability or agenesis of the ciliary central microtubules due to loss of their normal radial spoke head tethering.
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Affiliation(s)
- Alexandros Onoufriadis
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK Present address: Department of Medical and Molecular Genetics, Division of Genetics and Molecular Medicine, King's College London School of Medicine, Guy's Hospital, London SE1 9RT, UK
| | - Amelia Shoemark
- Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Trust, Sydney Street, London SW3 6NP, UK
| | - Miriam Schmidts
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Mitali Patel
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Gina Jimenez
- Laboratoire Cardiogénétique, Equipe d'Accueil 4173, Université Lyon 1, Hôpital Nord-Ouest, Villefranche sur Saône, Lyon, France Laboratoire Cardiogénétique, Hospices Civils de Lyon, Groupe Hospitalier Est, 69677 Bron, France
| | - Hui Liu
- Laboratoire Cardiogénétique, Equipe d'Accueil 4173, Université Lyon 1, Hôpital Nord-Ouest, Villefranche sur Saône, Lyon, France Laboratoire Cardiogénétique, Hospices Civils de Lyon, Groupe Hospitalier Est, 69677 Bron, France
| | - Biju Thomas
- Department of Infection, Immunity and Inflammation, Division of Child Health, CSB, University of Leicester, Leicester LE2 7LX, UK
| | - Mellisa Dixon
- Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Trust, Sydney Street, London SW3 6NP, UK
| | - Robert A Hirst
- Department of Infection, Immunity and Inflammation, Division of Child Health, CSB, University of Leicester, Leicester LE2 7LX, UK
| | - Andrew Rutman
- Department of Infection, Immunity and Inflammation, Division of Child Health, CSB, University of Leicester, Leicester LE2 7LX, UK
| | - Thomas Burgoyne
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Christopher Williams
- Department of Infection, Immunity and Inflammation, Division of Child Health, CSB, University of Leicester, Leicester LE2 7LX, UK
| | - Juliet Scully
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Florence Bolard
- Service de Pneumologie, Centre Hospitalier Régional de Roubaix, Hôpital Victor Provo, Roubaix, France
| | - Jean-Jacques Lafitte
- Département de Pneumologie, Centre Hospitalier Régional Universitaire de Lille, Hôpital Albert Calmette, Université Lille 2, Lille, France
| | - Philip L Beales
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Claire Hogg
- Department of Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Trust, Sydney Street, London SW3 6NP, UK
| | - Pinfen Yang
- Department of Biology, Marquette University, Milwaukee, WI 53233, USA
| | - Eddie M K Chung
- General and Adolescent Paediatric Unit, Institute of Child Health, University College London, London, UK
| | - Richard D Emes
- School of Veterinary Medicine and Science, University of Nottingham, Leicestershire LE12 5RD, UK Advanced Data Analysis Centre, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Christopher O'Callaghan
- Department of Infection, Immunity and Inflammation, Division of Child Health, CSB, University of Leicester, Leicester LE2 7LX, UK Department of Respiratory Medicine, Portex Unit, Institute of Child Health, University College London and Great Ormond Street Hospital, 30 Guilford Street, London WC1N 1EH, UK
| | | | - Patrice Bouvagnet
- Laboratoire Cardiogénétique, Equipe d'Accueil 4173, Université Lyon 1, Hôpital Nord-Ouest, Villefranche sur Saône, Lyon, France Laboratoire Cardiogénétique, Hospices Civils de Lyon, Groupe Hospitalier Est, 69677 Bron, France Service de Cardiologie Pédiatrique, Hospices Civils de Lyon, Groupe Hospitalier Est, 69677 Bron, France
| | - Hannah M Mitchison
- Molecular Medicine Unit and Birth Defects Research Centre, Institute of Child Health, University College London, London WC1N 1EH, UK
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27
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Cibert C. Bending, twisting and beating trunk robot bioinspired from the '3 + 0' axoneme. BIOINSPIRATION & BIOMIMETICS 2013; 8:026006. [PMID: 23579109 DOI: 10.1088/1748-3182/8/2/026006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The axoneme is the skeleton and motor axis of flagella and cilia in eukaryotic organisms. Basically it consists of a series of longitudinal fibers (outer doublets of microtubules) that design a cylinder and whose sliding, due to the coordinated activities of dedicated molecular motors (the dynein arms), is converted into a bending because outer doublets pairs are stabilized by elastic links (the nexine molecules). In spite of these interesting mechanical properties, mechanical and robotics engineers have never considered this amazing molecular machinery as a model. The aim of this paper is to propose the robotic design and the kinematic modeling of the '3 + 0' axoneme that makes motile the flagellum of Diplauxis hatti, the simplest that exists. The model that we propose bends and twists and combines the two movements. It is able to propagate wave trains that could be involved in the development of biomimetic actuators of various mechanisms such as (sub)aquatic robotic propellers as well as robotic trunks.
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Affiliation(s)
- Christian Cibert
- Institut des Sciences et Techniques des Yvelines - ISTY, 10-12, Avenue de l'Europe F-78140 Vélizy, France.
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28
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Carbajal-González BI, Heuser T, Fu X, Lin J, Smith BW, Mitchell DR, Nicastro D. Conserved structural motifs in the central pair complex of eukaryotic flagella. Cytoskeleton (Hoboken) 2013; 70:101-120. [PMID: 23281266 PMCID: PMC3914236 DOI: 10.1002/cm.21094] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/19/2012] [Accepted: 11/21/2012] [Indexed: 11/11/2022]
Abstract
Cilia and flagella are conserved hair-like appendages of eukaryotic cells that function as sensing and motility generating organelles. Motility is driven by thousands of axonemal dyneins that require precise regulation. One essential motility regulator is the central pair complex (CPC) and many CPC defects cause paralysis of cilia/flagella. Several human diseases, such as immotile cilia syndrome, show CPC abnormalities, but little is known about the detailed three-dimensional (3D) structure and function of the CPC. The CPC is located in the center of typical [9+2] cilia/flagella and is composed of two singlet microtubules (MTs), each with a set of associated projections that extend toward the surrounding nine doublet MTs. Using cryo-electron tomography coupled with subtomogram averaging, we visualized and compared the 3D structures of the CPC in both the green alga Chlamydomonas and the sea urchin Strongylocentrotus at the highest resolution published to date. Despite the evolutionary distance between these species, their CPCs exhibit remarkable structural conservation. We identified several new projections, including those that form the elusive sheath, and show that the bridge has a more complex architecture than previously thought. Organism-specific differences include the presence of MT inner proteins in Chlamydomonas, but not Strongylocentrotus, and different overall outlines of the highly connected projection network, which forms a round-shaped cylinder in algae, but is more oval in sea urchin. These differences could be adaptations to the mechanical requirements of the rotating CPC in Chlamydomonas, compared to the Strongylocentrotus CPC which has a fixed orientation.
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Affiliation(s)
| | - Thomas Heuser
- Biology Department, Rosenstiel Center, MS029, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Xiaofeng Fu
- Biology Department, Rosenstiel Center, MS029, Brandeis University, 415 South Street, Waltham, MA 02454, USA
- Howard Hughes Medical Institute, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Jianfeng Lin
- Biology Department, Rosenstiel Center, MS029, Brandeis University, 415 South Street, Waltham, MA 02454, USA
| | - Brandon W. Smith
- Department of Cell and Developmental Biology, Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
| | - David R. Mitchell
- Department of Cell and Developmental Biology, Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
| | - Daniela Nicastro
- Biology Department, Rosenstiel Center, MS029, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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29
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Electron Microscopy of Flagella, Primary Cilia, and Intraflagellar Transport in Flat-Embedded Cells. Methods Enzymol 2013; 524:243-63. [DOI: 10.1016/b978-0-12-397945-2.00014-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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30
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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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31
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Cryoelectron tomography reveals doublet-specific structures and unique interactions in the I1 dynein. Proc Natl Acad Sci U S A 2012; 109:E2067-76. [PMID: 22733763 DOI: 10.1073/pnas.1120690109] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Cilia and flagella are highly conserved motile and sensory organelles in eukaryotes, and defects in ciliary assembly and motility cause many ciliopathies. The two-headed I1 inner arm dynein is a critical regulator of ciliary and flagellar beating. To understand I1 architecture and function better, we analyzed the 3D structure and composition of the I1 dynein in Chlamydomonas axonemes by cryoelectron tomography and subtomogram averaging. Our data revealed several connections from the I1 dynein to neighboring structures that are likely to be important for assembly and/or regulation, including a tether linking one I1 motor domain to the doublet microtubule and doublet-specific differences potentially contributing to the asymmetrical distribution of dynein activity required for ciliary beating. We also imaged three I1 mutants and analyzed their polypeptide composition using 2D gel-based proteomics. Structural and biochemical comparisons revealed the likely location of the regulatory IC138 phosphoprotein and its associated subcomplex. Overall, our studies demonstrate that I1 dynein is connected to multiple structures within the axoneme, and therefore ideally positioned to integrate signals that regulate ciliary motility.
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Pigino G, Maheshwari A, Bui KH, Shingyoji C, Kamimura S, Ishikawa T. Comparative structural analysis of eukaryotic flagella and cilia from Chlamydomonas, Tetrahymena, and sea urchins. J Struct Biol 2012; 178:199-206. [PMID: 22406282 DOI: 10.1016/j.jsb.2012.02.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 10/22/2011] [Accepted: 02/17/2012] [Indexed: 10/28/2022]
Abstract
Although eukaryotic flagella and cilia all share the basic 9+2 microtubule-organization of their internal axonemes, and are capable of generating bending-motion, the waveforms, amplitudes, and velocities of the bending-motions are quite diverse. To explore the structural basis of this functional diversity of flagella and cilia, we here compare the axonemal structure of three different organisms with widely divergent bending-motions by electron cryo-tomography. We reconstruct the 3D structure of the axoneme of Tetrahymena cilia, and compare it with the axoneme of the flagellum of sea urchin sperm, as well as with the axoneme of Chlamydomonas flagella, which we analyzed previously. This comparative structural analysis defines the diversity of molecular architectures in these organisms, and forms the basis for future correlation with their different bending-motions.
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Affiliation(s)
- Gaia Pigino
- Biomolecular Research Laboratory, Paul Scherrer Institute, Switzerland
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Ultrastructure of Allapsa vibrans and the body plan of Glissomonadida (Cercozoa). Protist 2011; 163:165-87. [PMID: 22209009 DOI: 10.1016/j.protis.2011.10.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Accepted: 10/15/2011] [Indexed: 11/23/2022]
Abstract
Biciliate, gliding zooflagellate Cercozoa are globally the most abundant and genetically diverse predators in soil (glissomonads and cercomonads). We present the first detailed ultrastructural study of a phylogenetically well-characterized glissomonad, Allapsa vibrans. There are two ventral posterior centriolar roots as in Cercomonadida, but fewer other microtubular roots. Allapsa's centriolar roots and rhizoplast basically resemble those of the less well studied glissomonads Bodomorpha and Neoheteromita. The posterior centriole of Allapsa attaches laterally to the base of the anterior centriole and to the nucleus by striated fibrillar connectors and nests in a shallow cup-like ventrolateral depression; two broad fans of single microtubules line the cup's posterior and inner side. The anterior centriole has a dorsal two-microtubule root and probably also a singlet root. Its medium-length ciliary transition zones have a proximal hub-lattice and a prominent dense distal transverse plate/collar complex. Golgi bodies are anterior/paranuclear; isodiametric extrusomes are anterior mid-ventral. Tubulicristate mitochondria attach to the nucleus, as do prominent microbodies. We characterize the body plan of glissomonads, comparing it with other Sarcomonadea: their sister group (Pansomonadida) and the phylogenetically more distant Cercomonadida. We discuss glissomonad radiation into families Sandonidae, Proleptomonadidae, Dujardinidae, Bodomorphidae and Allapsidae, establishing Aurigamonadidae fam. n. for the amoeboflagellate pansomonad Aurigamonas.
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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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Kotov NV, Bates DG, Gizatullina AN, Gilaziev B, Khairullin RN, Chen MZQ, Drozdov I, Umezawa Y, Hundhausen C, Aleksandrov A, Yan XG, Spurgeon SK, Smales CM, Valeyev NV. Computational modelling elucidates the mechanism of ciliary regulation in health and disease. BMC SYSTEMS BIOLOGY 2011; 5:143. [PMID: 21920041 PMCID: PMC3224258 DOI: 10.1186/1752-0509-5-143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 09/15/2011] [Indexed: 12/23/2022]
Abstract
Background Ciliary dysfunction leads to a number of human pathologies, including primary ciliary dyskinesia, nephronophthisis, situs inversus pathology or infertility. The mechanism of cilia beating regulation is complex and despite extensive experimental characterization remains poorly understood. We develop a detailed systems model for calcium, membrane potential and cyclic nucleotide-dependent ciliary motility regulation. Results The model describes the intimate relationship between calcium and potassium ionic concentrations inside and outside of cilia with membrane voltage and, for the first time, describes a novel type of ciliary excitability which plays the major role in ciliary movement regulation. Our model describes a mechanism that allows ciliary excitation to be robust over a wide physiological range of extracellular ionic concentrations. The model predicts the existence of several dynamic modes of ciliary regulation, such as the generation of intraciliary Ca2+ spike with amplitude proportional to the degree of membrane depolarization, the ability to maintain stable oscillations, monostable multivibrator regimes, all of which are initiated by variability in ionic concentrations that translate into altered membrane voltage. Conclusions Computational investigation of the model offers several new insights into the underlying molecular mechanisms of ciliary pathologies. According to our analysis, the reported dynamic regulatory modes can be a physiological reaction to alterations in the extracellular environment. However, modification of the dynamic modes, as a result of genetic mutations or environmental conditions, can cause a life threatening pathology.
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Affiliation(s)
- Nikolay V Kotov
- Centre for Molecular Processing, School of Biosciences, University of Kent, Canterbury, Kent, UK
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Riedel-Kruse IH, Hilfinger A, Howard J, Jülicher F. How molecular motors shape the flagellar beat. HFSP JOURNAL 2011; 1:192-208. [PMID: 19404446 DOI: 10.2976/1.2773861] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 07/04/2007] [Indexed: 11/19/2022]
Abstract
Cilia and eukaryotic flagella are slender cellular appendages whose regular beating propels cells and microorganisms through aqueous media. The beat is an oscillating pattern of propagating bends generated by dynein motor proteins. A key open question is how the activity of the motors is coordinated in space and time. To elucidate the nature of this coordination we inferred the mechanical properties of the motors by analyzing the shape of beating sperm: Steadily beating bull sperm were imaged and their shapes were measured with high precision using a Fourier averaging technique. Comparing our experimental data with wave forms calculated for different scenarios of motor coordination we found that only the scenario of interdoublet sliding regulating motor activity gives rise to satisfactory fits. We propose that the microscopic origin of such "sliding control" is the load dependent detachment rate of motors. Agreement between observed and calculated wave forms was obtained only if significant sliding between microtubules occurred at the base. This suggests a novel mechanism by which changes in basal compliance could reverse the direction of beat propagation. We conclude that the flagellar beat patterns are determined by an interplay of the basal properties of the axoneme and the mechanical feedback of dynein motors.
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Kohno T, Wakabayashi KI, Diener DR, Rosenbaum JL, Kamiya R. Subunit interactions within the Chlamydomonas flagellar spokehead. Cytoskeleton (Hoboken) 2011; 68:237-46. [PMID: 21391306 DOI: 10.1002/cm.20507] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 02/08/2011] [Indexed: 11/10/2022]
Abstract
The radial spoke (RS)/central pair (CP) system in cilia and flagella plays an essential role in the regulation of force generation by dynein, the motor protein that drives cilia/flagella movements. Mechanical and mechanochemicl interactions between the CP and the distal part of the RS, the spokehead, should be crucial for this control; however, the details of interaction are totally unknown. As an initial step toward an understanding of the RS-CP interaction, we examined the protein-protein interactions between the five spokehead proteins (radial spoke protein (RSP)1, RSP4, RSP6, RSP9, and RSP10) and three spoke stalk proteins (RSP2, RSP5, and RSP23), all expressed as recombinant proteins. Three of them were shown to have physiological activities by electroporation-mediated protein delivery into mutants deficient in the respective proteins. Glutathione S-transferase pulldown assays in vitro detected interactions in 10 out of 64 pairs of recombinants. In addition, chemical crosslinking of axonemes using five reagents detected seven kinds of interactions between the RS subunits in situ. Finally, in the mixture of the recombinant spokehead subunits, RSP1, RSP4, RSP6, and RSP9 formed a 7-10S complex as detected by sucrose density gradient centrifugation. It may represent a partial assembly of the spokehead. From these results, we propose a model of interactions taking place between the spokehead subunits.
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Affiliation(s)
- Takahiro Kohno
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
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Bending of the "9+2" axoneme analyzed by the finite element method. J Theor Biol 2010; 264:1089-101. [PMID: 20380841 DOI: 10.1016/j.jtbi.2010.03.040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Revised: 03/26/2010] [Accepted: 03/29/2010] [Indexed: 11/21/2022]
Abstract
Many data demonstrate that the regulation of the bending polarity of the "9+2" axoneme is supported by the curvature itself, making the internal constraints central in this process, adjusting either the physical characteristics of the machinery or the activity of the enzymes involved in different pathways. Among them, the very integrated Geometric Clutch model founds this regulation on the convenient adjustments of the probability of interaction between the dynein arms and the beta-tubulin monomers of the outer doublet pairs on which they walk. Taking into consideration (i) the deviated bending of the outer doublets pairs (Cibert, C., Heck, J.-V., 2004. Cell Motil. Cytoskeleton 59, 153-168), (ii) the internal tensions of the radial spokes and the tangential links (nexin links, dynein arms), (iii) a theoretical 5 microm long proximal segment of the axoneme and (iv) the short proximal segment of the axoneme, we have reevaluated the adjustments of these intervals using a finite element approach. The movements we have calculated within the axonemal cylinder are consistent with the basic hypothesis that found the Geometric Clutch model, except that the axonemal side where the dynein arms are active increases the intervals between the two neighbor outer doublet pairs. This result allows us to propose a mechanism of bending reversion of the axoneme, involving the concerted ignition of the molecular engines along the two opposite sides of the axoneme delineated by the bending plane.
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Lindemann CB, Lesich KA. Flagellar and ciliary beating: the proven and the possible. J Cell Sci 2010; 123:519-28. [PMID: 20145000 DOI: 10.1242/jcs.051326] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The working mechanism of the eukaryotic flagellar axoneme remains one of nature's most enduring puzzles. The basic mechanical operation of the axoneme is now a story that is fairly complete; however, the mechanism for coordinating the action of the dynein motor proteins to produce beating is still controversial. Although a full grasp of the dynein switching mechanism remains elusive, recent experimental reports provide new insights that might finally disclose the secrets of the beating mechanism: the special role of the inner dynein arms, especially dynein I1 and the dynein regulatory complex, the importance of the dynein microtubule-binding affinity at the stalk, and the role of bending in the selection of the active dynein group have all been implicated by major new evidence. This Commentary considers this new evidence in the context of various hypotheses of how axonemal dynein coordination might work.
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Affiliation(s)
- Charles B Lindemann
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA.
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40
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DiPetrillo CG, Smith EF. Pcdp1 is a central apparatus protein that binds Ca(2+)-calmodulin and regulates ciliary motility. ACTA ACUST UNITED AC 2010; 189:601-12. [PMID: 20421426 PMCID: PMC2867295 DOI: 10.1083/jcb.200912009] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A complex that localizes to the C1d central pair projection of cilia controls flagellar waveform and beat frequency in response to calcium. For all motile eukaryotic cilia and flagella, beating is regulated by changes in intraciliary calcium concentration. Although the mechanism for calcium regulation is not understood, numerous studies have shown that calmodulin (CaM) is a key axonemal calcium sensor. Using anti-CaM antibodies and Chlamydomonas reinhardtii axonemal extracts, we precipitated a complex that includes four polypeptides and that specifically interacts with CaM in high [Ca2+]. One of the complex members, FAP221, is an orthologue of mammalian Pcdp1 (primary ciliary dyskinesia protein 1). Both FAP221 and mammalian Pcdp1 specifically bind CaM in high [Ca2+]. Reduced expression of Pcdp1 complex members in C. reinhardtii results in failure of the C1d central pair projection to assemble and significant impairment of motility including uncoordinated bends, severely reduced beat frequency, and altered waveforms. These combined results reveal that the central pair Pcdp1 (FAP221) complex is essential for control of ciliary motility.
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New Insights into the Roles of Molecular Chaperones in Chlamydomonas and Volvox. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 285:75-113. [DOI: 10.1016/b978-0-12-381047-2.00002-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Abstract
Eukaryotic flagella and cilia have a remarkably uniform internal 'engine' known as the '9+2' axoneme. With few exceptions, the function of cilia and flagella is to beat rhythmically and set up relative motion between themselves and the liquid that surrounds them. The molecular basis of axonemal movement is understood in considerable detail, with the exception of the mechanism that provides its rhythmical or oscillatory quality. Some kind of repetitive 'switching' event is assumed to occur; there are several proposals regarding the nature of the 'switch' and how it might operate. Herein I first summarise all the factors known to influence the rate of the oscillation (the beating frequency). Many of these factors exert their effect through modulating the mean sliding velocity between the nine doublet microtubules of the axoneme, this velocity being the determinant of bend growth rate and bend propagation rate. Then I explain six proposed mechanisms for flagellar oscillation and review the evidence on which they are based. Finally, I attempt to derive an economical synthesis, drawing for preference on experimental research that has been minimally disruptive of the intricate structure of the axoneme. The 'provisional synthesis' is that flagellar oscillation emerges from an effect of passive sliding direction on the dynein arms. Sliding in one direction facilitates force-generating cycles and dynein-to-dynein synchronisation along a doublet; sliding in the other direction is inhibitory. The direction of the initial passive sliding normally oscillates because it is controlled hydrodynamically through the alternating direction of the propulsive thrust. However, in the absence of such regulation, there can be a perpetual, mechanical self-triggering through a reversal of sliding direction due to the recoil of elastic structures that deform as a response to the prior active sliding. This provisional synthesis may be a useful basis for further examination of the problem.
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Affiliation(s)
- David M Woolley
- Department of Physiology and Pharmacology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, U.K.
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Abstract
Immunogold electron microscopy is a classic high-resolution method for the selective localization of macromolecules in the context of cells and subcellular structures. Specific antibodies are used to affix small particles of colloidal gold, which are easily visible in the electron microscope, to the macromolecule of interest. There are different immunogold-labeling techniques; in the postembedding immunogold-labeling technique, the biological material is first fixed, dehydrated, and embedded in resin and the antibody reactions are done on the sectioned material. In the preembedding immunogold-labeling technique, the antibody reactions are carried out prior to fixation, dehydration, and resin embedding of the biological specimen. The whole-mount immunogold-labeling technique does not involve resin embedding at all; the material is applied to an electron microscopy grid and the antibody reactions are carried out on the grid. The aim of this chapter is to describe in detail postembedding and preembedding techniques applicable for the immunogold labeling of components of Chlamydomonas flagella and basal bodies. Special emphasis is put on the flat embedding of Chlamydomonas cells, which allows the analysis of individual flagella along their whole length, a method especially suitable to the study of intraflagellar transport (IFT). Depending on the fixation protocol and resin used, such flat embeddings can be utilized for the localization of components of the IFT machinery by postembedding immunogold labeling or the ultrastructural analysis of the IFT complex by standard electron microscopy or electron tomography.
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Abstract
Eukaryotic flagella and cilia are alternative names, for the slender cylindrical protrusions of a cell (240nm diameter, approximately 12,800nm-long in Chlamydomonas reinhardtii) that propel a cell or move fluid. Cilia are extraordinarily successful complex organelles abundantly found in animals performing many tasks. They play a direct or developmental role in the sensors of fluid flow, light, sound, gravity, smells, touch, temperature, and taste in mammals. The failure of cilia can lead to hydrocephalus, infertility, and blindness. However, in spite of their large role in human function and pathology, there is as yet no consensus on how cilia beat and perform their many functions, such as moving fluids in brain ventricles and lungs and propelling and steering sperm, larvae, and many microorganisms. One needs to understand and analyze ciliary beating and its hydrodynamic interactions. This chapter provides a guide for measuring, analyzing, and interpreting ciliary behavior in various contexts studied in the model system of Chlamydomonas. It describes: (1) how cilia work as self-organized beating structures (SOBSs), (2) the overlaid control in the cilia that optimizes the SOBS to achieve cell dispersal, phototaxis steering, and avoidance of obstacles, (3) the assay of a model intracellular signal processing system that responds to multiple external and internal inputs, choosing mode of behavior and then controlling the cilia, (4) how cilia sense their environment, and (5) potentially an assay of ciliary performance for toxicology or medical assessment.
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Affiliation(s)
- Kenneth W Foster
- Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA
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45
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Mitchell DR, Smith B. Analysis of the central pair microtubule complex in Chlamydomonas reinhardtii. Methods Cell Biol 2009; 92:197-213. [PMID: 20409807 DOI: 10.1016/s0091-679x(08)92013-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The central pair microtubule complex in Chlamydomonas flagella has been well characterized as a regulator of flagellar dynein activity, but many aspects of this regulation depend on specific interactions between the asymmetric central pair structure and radial spokes, which appear symmetrically arranged along all nine outer doublet microtubules. Relationships between central pair-radial spoke interactions and dynein regulation have been difficult to understand because the Chlamydomonas central pair is twisted in vivo and rotates during bend propagation. Here we describe genetic and biochemical methods of dissecting the Chlamydomonas central pair and electron microscopic methods useful to determine structure-function relationships in this complex.
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Affiliation(s)
- David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
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46
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Elam CA, Sale WS, Wirschell M. The regulation of dynein-driven microtubule sliding in Chlamydomonas flagella by axonemal kinases and phosphatases. Methods Cell Biol 2009; 92:133-51. [PMID: 20409803 DOI: 10.1016/s0091-679x(08)92009-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The purpose of this chapter is to review the methodology and advances that have revealed conserved signaling proteins that are localized in the 9+2 ciliary axoneme for regulating motility. Diverse experimental systems have revealed that ciliary and eukaryotic flagellar motility is regulated by second messengers including calcium, pH, and cyclic nucleotides. In addition, recent advances in in vitro functional studies, taking advantage of isolated axonemes, pharmacological approaches, and biochemical analysis of axonemes have demonstrated that otherwise ubiquitous, conserved protein kinases and phosphatases are transported to and anchored in the axoneme. Here, we focus on the functional/pharmacological, genetic, and biochemical approaches in the model genetic system Chlamydomonas that have revealed highly conserved kinases, anchoring proteins (e.g., A-kinase anchoring proteins), and phosphatases that are physically located in the axoneme where they play a direct role in control of motility.
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Affiliation(s)
- Candice A Elam
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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Pigino G, Geimer S, Lanzavecchia S, Paccagnini E, Cantele F, Diener DR, Rosenbaum JL, Lupetti P. Electron-tomographic analysis of intraflagellar transport particle trains in situ. ACTA ACUST UNITED AC 2009; 187:135-48. [PMID: 19805633 PMCID: PMC2762096 DOI: 10.1083/jcb.200905103] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Ultrastructural study of Chlamydomonas cilia shows that anterograde IFT particles form trains that are long and narrow, while retrograde IFT form short, compact particle trains. Intraflagellar transport (IFT) is the bidirectional movement of multipolypeptide particles between the ciliary membrane and the axonemal microtubules, and is required for the assembly, maintenance, and sensory function of cilia and flagella. In this paper, we present the first high-resolution ultrastructural analysis of trains of flagellar IFT particles, using transmission electron microscopy and electron-tomographic analysis of sections from flat-embedded Chlamydomonas reinhardtii cells. Using wild-type and mutant cells with defects in IFT, we identified two different types of IFT trains: long, narrow trains responsible for anterograde transport; and short, compact trains underlying retrograde IFT. Both types of trains have characteristic repeats and patterns that vary as one sections longitudinally through the trains of particles. The individual IFT particles are highly complex, bridged to each other and to the outer doublet microtubules, and are closely apposed to the inner surface of the flagellar membrane.
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Affiliation(s)
- Gaia Pigino
- Dipartimento di Biologia Evolutiva, Università di Siena, 53100 Siena, Italy
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48
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Emergence of Animals from Heat Engines – Part 1. Before the Snowball Earths. ENTROPY 2009. [DOI: 10.3390/e11030463] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ralston KS, Kabututu ZP, Melehani JH, Oberholzer M, Hill KL. The Trypanosoma brucei flagellum: moving parasites in new directions. Annu Rev Microbiol 2009; 63:335-62. [PMID: 19575562 PMCID: PMC3821760 DOI: 10.1146/annurev.micro.091208.073353] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
African trypanosomes are devastating human and animal pathogens. Trypanosoma brucei rhodesiense and T. b. gambiense subspecies cause the fatal human disease known as African sleeping sickness. It is estimated that several hundred thousand new infections occur annually and the disease is fatal if untreated. T. brucei is transmitted by the tsetse fly and alternates between bloodstream-form and insect-form life cycle stages that are adapted to survive in the mammalian host and the insect vector, respectively. The importance of the flagellum for parasite motility and attachment to the tsetse fly salivary gland epithelium has been appreciated for many years. Recent studies have revealed both conserved and novel features of T. brucei flagellum structure and composition, as well as surprising new functions that are outlined here. These discoveries are important from the standpoint of understanding trypanosome biology and identifying novel drug targets, as well as for advancing our understanding of fundamental aspects of eukaryotic flagellum structure and function.
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Affiliation(s)
- Katherine S. Ralston
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095
| | - Zakayi P. Kabututu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095
| | - Jason H. Melehani
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095
| | - Michael Oberholzer
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095
| | - Kent L. Hill
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, California 90095
- Molecular Biology Institute, University of California, Los Angeles, California 90095
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50
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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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