1
|
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: 13] [Impact Index Per Article: 13.0] [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.
Collapse
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.
| |
Collapse
|
2
|
Abstract
The assembly and maintenance of most cilia and eukaryotic flagella depends on intraflagellar transport (IFT), the bidirectional movement of multi-megadalton IFT trains along the axonemal microtubules. These IFT trains function as carriers, moving ciliary proteins between the cell body and the organelle. Whereas tubulin, the principal protein of cilia, binds directly to IFT particle proteins, the transport of other ciliary proteins and complexes requires adapters that link them to the trains. Large axonemal substructures, such as radial spokes, outer dynein arms and inner dynein arms, assemble in the cell body before attaching to IFT trains, using the adapters ARMC2, ODA16 and IDA3, respectively. Ciliary import of several membrane proteins involves the putative adapter tubby-like protein 3 (TULP3), whereas membrane protein export involves the BBSome, an octameric complex that co-migrates with IFT particles. Thus, cells employ a variety of adapters, each of which is substoichiometric to the core IFT machinery, to expand the cargo range of the IFT trains. This Review summarizes the individual and shared features of the known cargo adapters and discusses their possible role in regulating the transport capacity of the IFT pathway.
Collapse
Affiliation(s)
- Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
3
|
Differential requirements of IQUB for the assembly of radial spoke 1 and the motility of mouse cilia and flagella. Cell Rep 2022; 41:111683. [DOI: 10.1016/j.celrep.2022.111683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/31/2022] [Accepted: 10/27/2022] [Indexed: 11/23/2022] Open
|
4
|
Lechtreck KF, Liu Y, Dai J, Alkhofash RA, Butler J, Alford L, Yang P. Chlamydomonas ARMC2/PF27 is an obligate cargo adapter for intraflagellar transport of radial spokes. eLife 2022; 11:74993. [PMID: 34982025 PMCID: PMC8789290 DOI: 10.7554/elife.74993] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 01/03/2022] [Indexed: 12/19/2022] Open
Abstract
Intraflagellar transport (IFT) carries proteins into flagella but how IFT trains interact with the large number of diverse proteins required to assemble flagella remains largely unknown. Here, we show that IFT of radial spokes in Chlamydomonas requires ARMC2/PF27, a conserved armadillo repeat protein associated with male infertility and reduced lung function. Chlamydomonas ARMC2 was highly enriched in growing flagella and tagged ARMC2 and the spoke protein RSP3 co-migrated on anterograde trains. In contrast, a cargo and an adapter of inner and outer dynein arms moved independently of ARMC2, indicating that unrelated cargoes distribute stochastically onto the IFT trains. After concomitant unloading at the flagellar tip, RSP3 attached to the axoneme whereas ARMC2 diffused back to the cell body. In armc2/pf27 mutants, IFT of radial spokes was abolished and the presence of radial spokes was limited to the proximal region of flagella. We conclude that ARMC2 is a cargo adapter required for IFT of radial spokes to ensure their assembly along flagella. ARMC2 belongs to a growing class of cargo-specific adapters that enable flagellar transport of preassembled axonemal substructures by IFT.
Collapse
Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Yi Liu
- Department of Biological Sciences, Marquette University, Milwaukee, United States
| | - Jin Dai
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Rama A Alkhofash
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Jack Butler
- Department of Cellular Biology, University of Georgia, Athens, United States
| | - Lea Alford
- Division of Natural Sciences,, Oglethorpe University, Atlanta, United States
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, United States
| |
Collapse
|
5
|
Zhang X, Sun J, Lu Y, Zhang J, Shimada K, Noda T, Zhao S, Koyano T, Matsuyama M, Zhou S, Wu J, Ikawa M, Liu M. LRRC23 is a conserved component of the radial spoke that is necessary for sperm motility and male fertility in mice. J Cell Sci 2021; 134:jcs259381. [PMID: 34585727 PMCID: PMC10658914 DOI: 10.1242/jcs.259381] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 01/22/2023] Open
Abstract
Cilia and flagella are ancient structures that achieve controlled motor functions through the coordinated interaction based on microtubules and some attached projections. Radial spokes (RSs) facilitate the beating motion of these organelles by mediating signal transduction between dyneins and a central pair (CP) of singlet microtubules. RS complex isolation from Chlamydomonas axonemes enabled the detection of 23 radial spoke proteins (RSP1-RSP23), although the roles of some radial spoke proteins remain unknown. Recently, RSP15 has been reported to be bound to the stalk of RS2, but its homolog in mammals has not been identified. Herein, we show that Lrrc23 is an evolutionarily conserved testis-enriched gene encoding an RSP15 homolog in mice. We found that LRRC23 localizes to the RS complex within murine sperm flagella and interacts with RSPH3A and RSPH3B. The knockout of Lrrc23 resulted in male infertility due to RS disorganization and impaired motility in murine spermatozoa, whereas the ciliary beating was not significantly affected. These data indicate that LRRC23 is a key regulator that underpins the integrity of the RS complex within the flagella of mammalian spermatozoa, whereas it is dispensable in cilia. This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Xin Zhang
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Jiang Sun
- Research Institute for Microbial Diseases, Osaka University, Suita 565-0871 Osaka, Japan
- Graduate School of Medicine, Osaka University, Suita, 565-0871 Osaka, Japan
| | - Yonggang Lu
- Research Institute for Microbial Diseases, Osaka University, Suita 565-0871 Osaka, Japan
| | - Jintao Zhang
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Keisuke Shimada
- Research Institute for Microbial Diseases, Osaka University, Suita 565-0871 Osaka, Japan
| | - Taichi Noda
- Research Institute for Microbial Diseases, Osaka University, Suita 565-0871 Osaka, Japan
| | - Shuqin Zhao
- State Key Laboratory of Reproductive Medicine, Animal Core Facility of Nanjing Medical University, Nanjing 211166, China
| | - Takayuki Koyano
- Division of Molecular Genetics, Shigei Medical Research Institute, 701-0202 Okayama, Japan
| | - Makoto Matsuyama
- Division of Molecular Genetics, Shigei Medical Research Institute, 701-0202 Okayama, Japan
| | - Shushu Zhou
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Jiayan Wu
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita 565-0871 Osaka, Japan
- Graduate School of Medicine, Osaka University, Suita, 565-0871 Osaka, Japan
- The Institute of Medical Science, The University of Tokyo, Minato-ku, 108-8639 Tokyo, Japan
| | - Mingxi Liu
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| |
Collapse
|
6
|
Heme-binding protein CYB5D1 is a radial spoke component required for coordinated ciliary beating. Proc Natl Acad Sci U S A 2021; 118:2015689118. [PMID: 33875586 DOI: 10.1073/pnas.2015689118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coordinated beating is crucial for the function of multiple cilia. However, the molecular mechanism is poorly understood. Here, we characterize a conserved ciliary protein CYB5D1 with a heme-binding domain and a cordon-bleu ubiquitin-like domain. Mutation or knockdown of Cyb5d1 in zebrafish impaired coordinated ciliary beating in the otic vesicle and olfactory epithelium. Similarly, the two flagella of an insertional mutant of the CYB5D1 ortholog in Chlamydomonas (Crcyb5d1) showed an uncoordinated pattern due to a defect in the cis-flagellum. Biochemical analyses revealed that CrCYB5D1 is a radial spoke stalk protein that binds heme only under oxidizing conditions. Lack of CrCYB5D1 resulted in a reductive shift in flagellar redox state and slowing down of the phototactic response. Treatment of Crcyb5d1 with oxidants restored coordinated flagellar beating. Taken together, these data suggest that CrCYB5D1 may integrate environmental and intraciliary signals and regulate the redox state of cilia, which is crucial for the coordinated beating of multiple cilia.
Collapse
|
7
|
Distinct architecture and composition of mouse axonemal radial spoke head revealed by cryo-EM. Proc Natl Acad Sci U S A 2021; 118:2021180118. [PMID: 34871179 DOI: 10.1073/pnas.2021180118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The radial spoke (RS) heads of motile cilia and flagella contact projections of the central pair (CP) apparatus to coordinate motility, but the morphology is distinct for protozoa and metazoa. Here we show the murine RS head is compositionally distinct from that of Chlamydomonas Our reconstituted murine RS head core complex consists of Rsph1, Rsph3b, Rsph4a, and Rsph9, lacking Rsph6a and Rsph10b, whose orthologs exist in the protozoan RS head. We resolve its cryo-electron microscopy (cryo-EM) structure at 3.2-Å resolution. Our atomic model further reveals a twofold symmetric brake pad-shaped structure, in which Rsph4a and Rsph9 form a compact body extended laterally with two long arms of twisted Rsph1 β-sheets and potentially connected dorsally via Rsph3b to the RS stalk. Furthermore, our modeling suggests that the core complex contacts the periodic CP projections either rigidly through its tooth-shaped Rsph4a regions or elastically through both arms for optimized RS-CP interactions and mechanosignal transduction.
Collapse
|
8
|
Grossman-Haham I, Coudray N, Yu Z, Wang F, Zhang N, Bhabha G, Vale RD. Structure of the radial spoke head and insights into its role in mechanoregulation of ciliary beating. Nat Struct Mol Biol 2021; 28:20-28. [PMID: 33318704 PMCID: PMC7855469 DOI: 10.1038/s41594-020-00519-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 09/16/2020] [Indexed: 11/14/2022]
Abstract
Motile cilia power cell locomotion and drive extracellular fluid flow by propagating bending waves from their base to tip. The coordinated bending of cilia requires mechanoregulation by the radial spoke (RS) protein complexes and the microtubule central pair (CP). Despite their importance for ciliary motility across eukaryotes, the molecular function of the RSs is unknown. Here, we reconstituted the Chlamydomonas reinhardtii RS head that abuts the CP and determined its structure using single-particle cryo-EM to 3.1-Å resolution, revealing a flat, negatively charged surface supported by a rigid core of tightly intertwined proteins. Mutations in this core, corresponding to those involved in human ciliopathies, compromised the stability of the recombinant complex, providing a molecular basis for disease. Partially reversing the negative charge on the RS surface impaired motility in C. reinhardtii. We propose that the RS-head architecture is well-suited for mechanoregulation of ciliary beating through physical collisions with the CP.
Collapse
Affiliation(s)
- Iris Grossman-Haham
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
| | - Nicolas Coudray
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
- Applied Bioinformatics Laboratories, New York University School of Medicine, New York, NY, USA
| | - Zanlin Yu
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Feng Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Nan Zhang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
| | - Gira Bhabha
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | - Ronald D Vale
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
| |
Collapse
|
9
|
Poghosyan E, Iacovache I, Faltova L, Leitner A, Yang P, Diener DR, Aebersold R, Zuber B, Ishikawa T. The structure and symmetry of the radial spoke protein complex in Chlamydomonas flagella. J Cell Sci 2020; 133:jcs245233. [PMID: 32694165 DOI: 10.1242/jcs.245233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/25/2020] [Indexed: 12/27/2022] Open
Abstract
The radial spoke is a key element in a transducer apparatus controlling the motility of eukaryotic cilia. The transduction biomechanics is a long-standing question in cilia biology. The radial spoke has three regions - a spoke head, a bifurcated neck and a stalk. Although the neck and the stalk are asymmetric, twofold symmetry of the head has remained controversial. In this work we used single particle cryo-electron microscopy (cryo-EM) analysis to generate a 3D structure of the whole radial spoke at unprecedented resolution. We show the head region at 15 Å (1.5 nm) resolution and confirm twofold symmetry. Using distance constraints generated by cross-linking mass spectrometry, we locate two components, RSP2 and RSP4, at the head and neck regions. Our biophysical analysis of isolated RSP4, RSP9, and RSP10 affirmed their oligomeric state. Our results enable us to redefine the boundaries of the regions and propose a model of organization of the radial spoke component proteins.
Collapse
Affiliation(s)
- Emiliya Poghosyan
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
- ETH Zurich, Department of Biology, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Ioan Iacovache
- University of Bern, Institute of Anatomy, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Lenka Faltova
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Alexander Leitner
- ETH Zurich, Department of Biology, Institute of Molecular Systems Biology, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Dennis R Diener
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Ruedi Aebersold
- ETH Zurich, Department of Biology, Institute of Molecular Systems Biology, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
- University of Zurich, Faculty of Science, Rämistrasse 71, 8006 Zürich, Switzerland
| | - Benoit Zuber
- University of Bern, Institute of Anatomy, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Takashi Ishikawa
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
- ETH Zurich, Department of Biology, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| |
Collapse
|
10
|
Folcik AM, Haire T, Cutshaw K, Riddle M, Shola C, Nassani S, Rice P, Richardson B, Shah P, Nazamoddini-Kachouie N, Palmer A. Computer-Assisted Tracking of Chlamydomonas Species. FRONTIERS IN PLANT SCIENCE 2020; 10:1616. [PMID: 32076424 PMCID: PMC7006616 DOI: 10.3389/fpls.2019.01616] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/18/2019] [Indexed: 06/10/2023]
Abstract
The green algae Chlamydomonas reinhardtii is a model system for motility in unicellular organisms. Photo-, gravi-, and chemotaxis have previously been associated with C. reinhardtii, and observing the extent of these responses within a population of cells is crucial for refining our understanding of how this organism responds to changing environmental conditions. However, manually tracking and modeling a statistically viable number of samples of these microorganisms is an unreasonable task. We hypothesized that automated particle tracking systems are now sufficiently advanced to effectively characterize such populations. Here, we present an automated method to observe C. reinhardtii motility that allows us to identify individual cells as well as global information on direction, speed, and size. Nutrient availability effects on wild-type C. reinhardtii swimming speeds, as well as changes in speed and directionality in response to light, were characterized using this method. We also provide for the first time the swimming speeds of several motility-deficient mutant lines. While our present effort is focused around the unicellular green algae, C. reinhardtii, we confirm the general utility of this approach using Chlamydomonas moewusii, another member of this genus which contains over 300 species. Our work provides new tools for evaluating and modeling motility in this model organism and establishes the methodology for conducting similar experiments on other unicellular microorganisms.
Collapse
Affiliation(s)
- Alexandra M. Folcik
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Timothy Haire
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Kirstin Cutshaw
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Melissa Riddle
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Catherine Shola
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Sararose Nassani
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Paul Rice
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Brianna Richardson
- Department of Aerospace, Physics, and Space Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | - Pooja Shah
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
| | | | - Andrew Palmer
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, United States
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, Melbourne, FL, United States
- Aldrin Space Institute, Florida Institute of Technology, Melbourne, FL, United States
| |
Collapse
|
11
|
Rare Human Diseases: Model Organisms in Deciphering the Molecular Basis of Primary Ciliary Dyskinesia. Cells 2019; 8:cells8121614. [PMID: 31835861 PMCID: PMC6952885 DOI: 10.3390/cells8121614] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 12/02/2019] [Accepted: 12/10/2019] [Indexed: 12/17/2022] Open
Abstract
Primary ciliary dyskinesia (PCD) is a recessive heterogeneous disorder of motile cilia, affecting one per 15,000-30,000 individuals; however, the frequency of this disorder is likely underestimated. Even though more than 40 genes are currently associated with PCD, in the case of approximately 30% of patients, the genetic cause of the manifested PCD symptoms remains unknown. Because motile cilia are highly evolutionarily conserved organelles at both the proteomic and ultrastructural levels, analyses in the unicellular and multicellular model organisms can help not only to identify new proteins essential for cilia motility (and thus identify new putative PCD-causative genes), but also to elucidate the function of the proteins encoded by known PCD-causative genes. Consequently, studies involving model organisms can help us to understand the molecular mechanism(s) behind the phenotypic changes observed in the motile cilia of PCD affected patients. Here, we summarize the current state of the art in the genetics and biology of PCD and emphasize the impact of the studies conducted using model organisms on existing knowledge.
Collapse
|
12
|
Steinhauer J, Statman B, Fagan JK, Borck J, Surabhi S, Yarikipati P, Edelman D, Jenny A. Combover interacts with the axonemal component Rsp3 and is required for Drosophila sperm individualization. Development 2019; 146:dev179275. [PMID: 31391193 PMCID: PMC6765124 DOI: 10.1242/dev.179275] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/24/2019] [Indexed: 12/24/2022]
Abstract
Gamete formation is key to survival of higher organisms. In male animals, spermatogenesis gives rise to interconnected spermatids that differentiate and individualize into mature sperm, each tightly enclosed by a plasma membrane. In Drosophila melanogaster, individualization of sister spermatids requires the formation of specialized actin cones that synchronously move along the sperm tails, removing inter-spermatid bridges and most of the cytoplasm. Here, we show that Combover (Cmb), originally identified as an effector of planar cell polarity (PCP) under control of Rho kinase, is essential for sperm individualization. cmb mutants are male sterile, with actin cones that fail to move in a synchronized manner along the flagella, despite being correctly formed and polarized initially. These defects are germline autonomous, independent of PCP genes, and can be rescued by wild-type Cmb, but not by a version of Cmb in which known Rho kinase phosphorylation sites are mutated. Furthermore, Cmb binds to the axonemal component Radial spoke protein 3, knockdown of which causes similar individualization defects, suggesting that Cmb coordinates the individualization machinery with the microtubular axonemes.
Collapse
Affiliation(s)
| | - Benjamin Statman
- Department of Biology, Yeshiva University, New York, NY 10033, USA
| | - Jeremy K Fagan
- Department of Developmental and Molecular Biology and Department of Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Jacob Borck
- Department of Biology, Yeshiva University, New York, NY 10033, USA
| | - Satya Surabhi
- Department of Developmental and Molecular Biology and Department of Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Prathibha Yarikipati
- Department of Developmental and Molecular Biology and Department of Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Daniel Edelman
- Department of Biology, Yeshiva University, New York, NY 10033, USA
| | - Andreas Jenny
- Department of Developmental and Molecular Biology and Department of Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA
| |
Collapse
|
13
|
Zhu L, Liu H, Chen Y, Yan X, Zhu X. Rsph9 is critical for ciliary radial spoke assembly and central pair microtubule stability. Biol Cell 2018; 111:29-38. [PMID: 30383886 DOI: 10.1111/boc.201800060] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/26/2018] [Accepted: 10/30/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND INFORMATION In the "9+2"-type motile cilia, radial spokes (RSs) protruded from the nine peripheral microtubule doublets surround and interact with the central pair (CP) apparatus to regulate ciliary beat. RSPH9 is the human homologue of the essential protozoan RS head protein Rsp9. Its mutations in human primary ciliary dyskinesia patients, however, cause CP loss in a small portion of airway cilia without affecting the ciliary localization of other head proteins. RESULTS We characterized mouse Rsph9 and investigated its function in ependymal motile cilia. Rsph9 was specifically expressed in mouse tissues containing motile cilia and upregulated during multiciliation. Its ciliary localization complied with its putative role as an RS subunit. Depletion of Rsph9 by RNAi in mouse ependymal cilia resulted in a near complete CP loss and altered the ciliary beat pattern from planar to rotational. Multiple RS proteins, including those in the head, were also markedly downregulated in the Rsph9-depleted cilia. CONCLUSION Rsph9 is essential for both the RS head assembly and the CP maintenance in mammalian ependymal cilia. SIGNIFICANCE Our results help to understand the assembly and functions of mammalian RS and pathology of RS-related ciliopathy.
Collapse
Affiliation(s)
- Lei Zhu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Hao Liu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Yawen Chen
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Xiumin Yan
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China.,University of Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
14
|
Zhu X, Poghosyan E, Rezabkova L, Mehall B, Sakakibara H, Hirono M, Kamiya R, Ishikawa T, Yang P. The roles of a flagellar HSP40 ensuring rhythmic beating. Mol Biol Cell 2018; 30:228-241. [PMID: 30427757 PMCID: PMC6589562 DOI: 10.1091/mbc.e18-01-0047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
HSP40s are regarded as cochaperones, perpetually shuttling client polypeptides to HSP70s for refolding. However, many HSP40s that are central for disparate processes diverge from this paradigm. To elucidate the noncanonical mechanisms, we investigated HSP40 in the radial spoke (RS) complex in flagella. Disruption of the gene by the MRC1 transposon in Chlamydomonas resulted in jerky flagella. Traditional electron microscopy, cryo-electron tomography, and sub-tomogram analysis revealed RSs of various altered morphologies that, unexpectedly, differed between the two RS species. This indicates that HSP40 locks the RS into a functionally rigid conformation, facilitating its interactions with the adjacent central pair apparatus for transducing locally varied mechanical feedback, which permits rhythmic beating. Missing HSP40, like missing RSs, could be restored in a tip-to-base direction when HSP40 mutants fused with a HSP40 donor cell. However, without concomitant de novo RS assembly, the repair was exceedingly slow, suggesting HSP40/RS-coupled intraflagellar trafficking and assembly. Biochemical analysis and modeling uncovered spoke HSP40’s cochaperone traits. On the basis of our data, we propose that HSP40 accompanies its client RS precursor when traveling to the flagellar tip. Upon arrival, both refold in concert to assemble into the mature configuration. HSP40’s roles in chaperoning and structural maintenance shed new light on its versatility and flagellar biology.
Collapse
Affiliation(s)
- Xiaoyan Zhu
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Emiliya Poghosyan
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Lenka Rezabkova
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Bridget Mehall
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Hitoshi Sakakibara
- National Institute of Information and Communications Technology (NICT), Advanced ICT Research Institute, Hyogo 651-2492, Japan
| | - Masafumi Hirono
- Department of Frontier Bioscience, Hosei University, Tokyo 184-8584, Japan
| | - Ritsu Kamiya
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo 171-8588, Japan
| | - Takashi Ishikawa
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| |
Collapse
|
15
|
Sekiguchi M, Kameda S, Kurosawa S, Yoshida M, Yoshimura K. Thermotaxis in Chlamydomonas is brought about by membrane excitation and controlled by redox conditions. Sci Rep 2018; 8:16114. [PMID: 30382191 PMCID: PMC6208428 DOI: 10.1038/s41598-018-34487-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/18/2018] [Indexed: 11/09/2022] Open
Abstract
Temperature is physiologically critical for all living organisms, which cope with temperature stress using metabolic and behavioral responses. In unicellular and some multicellular organisms, thermotaxis is a behavioral response to avoid stressful thermal environments and promote accumulation in an optimal thermal environment. In this study, we examined whether Chlamydomonas reinhardtii, a unicellular green alga, demonstrated thermotaxis. We found that between 10 °C and 30 °C, Chlamydomonas cells migrated toward lower temperatures independent of cultivation temperature. Interestingly, when we applied reagents to change intracellular reduction-oxidation (redox) conditions, we saw that thermotaxis was enhanced, suppressed, or reversed, depending on the redox conditions and cultivation temperature. Thermotaxis was almost absent in ppr2 and ppr3 mutants, which cannot swim backward because of a defect in generating calcium current in flagella. The frequency of spontaneous backward swimming was lower at more favorable temperature, suggesting a pivotal role of spontaneous backward swimming generated by flagellar membrane excitation.
Collapse
Affiliation(s)
- Masaya Sekiguchi
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Shigetoshi Kameda
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Satoshi Kurosawa
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Megumi Yoshida
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan
| | - Kenjiro Yoshimura
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, 337-8570, Japan.
| |
Collapse
|
16
|
Abbasi F, Miyata H, Shimada K, Morohoshi A, Nozawa K, Matsumura T, Xu Z, Pratiwi P, Ikawa M. RSPH6A is required for sperm flagellum formation and male fertility in mice. J Cell Sci 2018; 131:jcs.221648. [PMID: 30185526 DOI: 10.1242/jcs.221648] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/23/2018] [Indexed: 01/09/2023] Open
Abstract
The flagellum is an evolutionarily conserved appendage used for sensing and locomotion. Its backbone is the axoneme and a component of the axoneme is the radial spoke (RS), a protein complex implicated in flagellar motility regulation. Numerous diseases occur if the axoneme is improperly formed, such as primary ciliary dyskinesia (PCD) and infertility. Radial spoke head 6 homolog A (RSPH6A) is an ortholog of Chlamydomonas RSP6 in the RS head and is evolutionarily conserved. While some RS head proteins have been linked to PCD, little is known about RSPH6A. Here, we show that mouse RSPH6A is testis-enriched and localized in the flagellum. Rsph6a knockout (KO) male mice are infertile as a result of their short immotile spermatozoa. Observation of the KO testis indicates that the axoneme can elongate but is disrupted before accessory structures are formed. Manchette removal is also impaired in the KO testis. Further, RSPH9, another radial spoke protein, disappeared in the Rsph6a KO flagella. These data indicate that RSPH6A is essential for sperm flagellar assembly and male fertility in mice.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Ferheen Abbasi
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Haruhiko Miyata
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Keisuke Shimada
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Akane Morohoshi
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kaori Nozawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Takafumi Matsumura
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Zoulan Xu
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Putri Pratiwi
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan .,Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan.,Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan.,The Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan
| |
Collapse
|
17
|
Dumas L, Zito F, Auroy P, Johnson X, Peltier G, Alric J. Structure-Function Analysis of Chloroplast Proteins via Random Mutagenesis Using Error-Prone PCR. PLANT PHYSIOLOGY 2018; 177:465-475. [PMID: 29703866 PMCID: PMC6001340 DOI: 10.1104/pp.17.01618] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 03/31/2018] [Indexed: 05/14/2023]
Abstract
Site-directed mutagenesis of chloroplast genes was developed three decades ago and has greatly advanced the field of photosynthesis research. Here, we describe a new approach for generating random chloroplast gene mutants that combines error-prone polymerase chain reaction of a gene of interest with chloroplast complementation of the knockout Chlamydomonas reinhardtii mutant. As a proof of concept, we targeted a 300-bp sequence of the petD gene that encodes subunit IV of the thylakoid membrane-bound cytochrome b6f complex. By sequencing chloroplast transformants, we revealed 149 mutations in the 300-bp target petD sequence that resulted in 92 amino acid substitutions in the 100-residue target subunit IV sequence. Our results show that this method is suited to the study of highly hydrophobic, multisubunit, and chloroplast-encoded proteins containing cofactors such as hemes, iron-sulfur clusters, and chlorophyll pigments. Moreover, we show that mutant screening and sequencing can be used to study photosynthetic mechanisms or to probe the mutational robustness of chloroplast-encoded proteins, and we propose that this method is a valuable tool for the directed evolution of enzymes in the chloroplast.
Collapse
Affiliation(s)
- Louis Dumas
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Aix-Marseille Université, Unité Mixte de Recherche 7265, BIAM, Commissariat à l'Energie Atomique Cadarache, 13115 Saint-Paul-lez-Durance, France
| | - Francesca Zito
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7099, University Paris Diderot, Sorbonne Paris Cité, PSL Research University, F-75005 Paris, France
| | - Pascaline Auroy
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Aix-Marseille Université, Unité Mixte de Recherche 7265, BIAM, Commissariat à l'Energie Atomique Cadarache, 13115 Saint-Paul-lez-Durance, France
| | - Xenie Johnson
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Aix-Marseille Université, Unité Mixte de Recherche 7265, BIAM, Commissariat à l'Energie Atomique Cadarache, 13115 Saint-Paul-lez-Durance, France
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Aix-Marseille Université, Unité Mixte de Recherche 7265, BIAM, Commissariat à l'Energie Atomique Cadarache, 13115 Saint-Paul-lez-Durance, France
| | - Jean Alric
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Aix-Marseille Université, Unité Mixte de Recherche 7265, BIAM, Commissariat à l'Energie Atomique Cadarache, 13115 Saint-Paul-lez-Durance, France jean.alric@cea
| |
Collapse
|
18
|
Zhu X, Poghosyan E, Gopal R, Liu Y, Ciruelas KS, Maizy Y, Diener DR, King SM, Ishikawa T, Yang P. General and specific promotion of flagellar assembly by a flagellar nucleoside diphosphate kinase. Mol Biol Cell 2017; 28:3029-3042. [PMID: 28877983 PMCID: PMC5662260 DOI: 10.1091/mbc.e17-03-0156] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 08/25/2017] [Accepted: 08/30/2017] [Indexed: 12/20/2022] Open
Abstract
NDK5 promotes assembly of motile cilia and flagella with its structure and protein phosphorylation–related reactions instead of the canonical NDK activity. The novel mechanisms and dominant-negative effect of mutated functional NDK5 reveal the remarkable versatility of a molecular platform that is used in diverse cellular processes. Nucleoside diphosphate kinases (NDKs) play a central role in diverse cellular processes using the canonical NDK activity or alternative mechanisms that remain poorly defined. Our study of dimeric NDK5 in a flagellar motility control complex, the radial spoke (RS), has revealed new modalities. The flagella in Chlamydomonas ndk5 mutant were paralyzed, albeit only deficient in three RS subunits. RS morphology appeared severely changed in averaged cryo-electron tomograms, suggesting that NDK5 is crucial for the intact spokehead formation as well as RS structural stability. Intriguingly, ndk5’s flagella were also short, resembling those of an allelic spoke-less mutant. All ndk5’s phenotypes were rescued by expressions of NDK5 or a mutated NDK5 lacking the canonical kinase activity. Importantly, the mutated NDK5 that appeared fully functional in ndk5 cells elicited a dominant-negative effect in wild-type cells, causing paralyzed short flagella with hypophosphorylated, less abundant, but intact RSs, and accumulated hypophosphorylated NDK5 in the cell body. We propose that NDK5 dimer is an RS structural subunit with an additional mechanism that uses cross-talk between the two NDK monomers to accelerate phosphorylation-related assembly of RSs and entire flagella.
Collapse
Affiliation(s)
- Xiaoyan Zhu
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Emiliya Poghosyan
- Biomolecular Research Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Radhika Gopal
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Yi Liu
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Kristine S Ciruelas
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Yousif Maizy
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| | - Dennis R Diener
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030-3305
| | - Takashi Ishikawa
- Biomolecular Research Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233
| |
Collapse
|
19
|
Zhu X, Liu Y, Yang P. Radial Spokes-A Snapshot of the Motility Regulation, Assembly, and Evolution of Cilia and Flagella. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a028126. [PMID: 27940518 DOI: 10.1101/cshperspect.a028126] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Propulsive forces generated by cilia and flagella are used in events that are critical for the thriving of diverse eukaryotic organisms in their environments. Despite distinctive strokes and regulations, the majority of them adopt the 9+2 axoneme that is believed to exist in the last eukaryotic common ancestor. Only a few outliers have opted for a simpler format that forsakes the signature radial spokes and the central pair apparatus, although both are unnecessary for force generation or rhythmicity. Extensive evidence has shown that they operate as an integral system for motility control. Recent studies have made remarkable progress on the radial spoke. This review will trace how the new structural, compositional, and evolutional insights pose significant implications on flagella biology and, conversely, ciliopathy.
Collapse
Affiliation(s)
- Xiaoyan Zhu
- The Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Yi Liu
- The Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Pinfen Yang
- The Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53201
| |
Collapse
|
20
|
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.
Collapse
Affiliation(s)
- Takashi Ishikawa
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.,Department of Biology, ETH Zurich, 5232 Villigen PSI, Switzerland
| |
Collapse
|
21
|
Linck RW, Chemes H, Albertini DF. The axoneme: the propulsive engine of spermatozoa and cilia and associated ciliopathies leading to infertility. J Assist Reprod Genet 2016; 33:141-56. [PMID: 26825807 PMCID: PMC4759005 DOI: 10.1007/s10815-016-0652-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 01/03/2016] [Indexed: 01/08/2023] Open
Affiliation(s)
- Richard W Linck
- Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Hector Chemes
- Center for Research in Endocrinology, National Research Council, CEDIE-CONICET, Endocrinology Division, Buenos Aires Children's Hospital, Gallo 1330, C1425SEFD, Buenos Aires, Argentina.
| | - David F Albertini
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, 66160, USA. .,The Center for Human Reproduction, New York, NY, USA.
| |
Collapse
|
22
|
Jeanson L, Copin B, Papon JF, Dastot-Le Moal F, Duquesnoy P, Montantin G, Cadranel J, Corvol H, Coste A, Désir J, Souayah A, Kott E, Collot N, Tissier S, Louis B, Tamalet A, de Blic J, Clement A, Escudier E, Amselem S, Legendre M. RSPH3 Mutations Cause Primary Ciliary Dyskinesia with Central-Complex Defects and a Near Absence of Radial Spokes. Am J Hum Genet 2015; 97:153-62. [PMID: 26073779 PMCID: PMC4571005 DOI: 10.1016/j.ajhg.2015.05.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/05/2015] [Indexed: 01/16/2023] Open
Abstract
Primary ciliary dyskinesia (PCD) is a rare autosomal-recessive condition resulting from structural and/or functional defects of the axoneme in motile cilia and sperm flagella. The great majority of mutations identified so far involve genes whose defects result in dynein-arm anomalies. By contrast, PCD due to CC/RS defects (those in the central complex [CC] and radial spokes [RSs]), which might be difficult to diagnose, remains mostly unexplained. We identified non-ambiguous RSPH3 mutations in 5 of 48 independent families affected by CC/RS defects. RSPH3, whose ortholog in the flagellated alga Chlamydomonas reinhardtii encodes a RS-stalk protein, is mainly expressed in respiratory and testicular cells. Its protein product, which localizes within the cilia of respiratory epithelial cells, was undetectable in airway cells from an individual with RSPH3 mutations and in whom RSPH23 (a RS-neck protein) and RSPH1 and RSPH4A (RS-head proteins) were found to be still present within cilia. In the case of RSPH3 mutations, high-speed-videomicroscopy analyses revealed the coexistence of immotile cilia and motile cilia with movements of reduced amplitude. A striking feature of the ultrastructural phenotype associated with RSPH3 mutations is the near absence of detectable RSs in all cilia in combination with a variable proportion of cilia with CC defects. Overall, this study shows that RSPH3 mutations contribute to disease in more than 10% of PCD-affected individuals with CC/RS defects, thereby allowing an accurate diagnosis to be made in such cases. It also unveils the key role of RSPH3 in the proper building of RSs and the CC in humans.
Collapse
Affiliation(s)
- Ludovic Jeanson
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France
| | - Bruno Copin
- Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Jean-François Papon
- INSERM UMR S955, Equipe 13, Université Paris-Est Créteil, Créteil 94000, France; Service d'Oto-Rhino-Laryngologie et de Chirurgie Cervico-Maxillo-Faciale, Hôpital Bicêtre, Assistance Publique - Hôpitaux de Paris, Le Kremlin-Bicêtre 94275, France
| | - Florence Dastot-Le Moal
- Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Philippe Duquesnoy
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France
| | - Guy Montantin
- Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Jacques Cadranel
- Service de Pneumologie-Centre Expert Maladies Pulmonaires Rares, Hôpital Tenon, Assistance Publique - Hôpitaux de Paris, Paris 75020, France; Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75020, France
| | - Harriet Corvol
- Service de Pneumologie Pédiatrique, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris and Centre National de Référence des Maladies Respiratoires Rares, Paris 75012, France; INSERM UMR S938, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France
| | - André Coste
- INSERM UMR S955, Equipe 13, Université Paris-Est Créteil, Créteil 94000, France; Service d'Oto-Rhino-Laryngologie et de Chirurgie Cervico-Faciale, Hôpital Intercommunal et Groupe Hospitalier Henri Mondor-Albert Chenevier, Assistance Publique - Hôpitaux de Paris, Créteil 94000, France
| | - Julie Désir
- Département de Génétique Médicale, Université Libre de Bruxelles and Hôpital Erasme, Brussels 1020, Belgium
| | - Anissa Souayah
- Service d'Oto-Rhino-Laryngologie, Hôpital Universitaire des Enfants Reine Fabiola, Brussels 1020, Belgium
| | - Esther Kott
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France
| | - Nathalie Collot
- Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Sylvie Tissier
- Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Bruno Louis
- INSERM UMR S955, Equipe 13, Université Paris-Est Créteil, Créteil 94000, France
| | - Aline Tamalet
- Service de Pneumologie Pédiatrique, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris and Centre National de Référence des Maladies Respiratoires Rares, Paris 75012, France
| | - Jacques de Blic
- Service de Pneumologie et Allergologie Pédiatriques, Groupe Hospitalier Necker-Enfants Malades, Assistance Publique - Hôpitaux de Paris and Université Paris Descartes, Paris 75015, France
| | - Annick Clement
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France; Service de Pneumologie Pédiatrique, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris and Centre National de Référence des Maladies Respiratoires Rares, Paris 75012, France
| | - Estelle Escudier
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France; Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| | - Serge Amselem
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France; Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France.
| | - Marie Legendre
- INSERM UMR S933, Université Pierre et Marie Curie (Paris 6), Sorbonne Universités, Paris 75012, France; Service de Génétique et Embryologie Médicales, Hôpital Armand Trousseau, Assistance Publique - Hôpitaux de Paris, Paris 75012, France
| |
Collapse
|
23
|
van Tilburg MF, Salles MGF, Silva MM, Moreira RA, Moreno FB, Monteiro-Moreira ACO, Martins JAM, Cândido MJD, Araújo AA, Moura AAA. Semen variables and sperm membrane protein profile of Saanen bucks (Capra hircus) in dry and rainy seasons of the northeastern Brazil (3°S). INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2015; 59:561-573. [PMID: 25086569 DOI: 10.1007/s00484-014-0869-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 07/01/2014] [Accepted: 07/02/2014] [Indexed: 06/03/2023]
Abstract
The Saanen is a highly productive breed, and for this reason, it has been raised in Brazil, but mostly under climate conditions completely different from where the breed originated. The objective of this study was to investigate variations in semen parameters and sperm membrane proteins from Saanen bucks (n = 7) raised in Northeastern Brazil, during dry season (September, October, and November) and rainy season (March, April, and May). We showed that during the dry season, sperm motility, concentration, and the percentage of normal sperm decreased as compared to the rainy season. Rectal temperatures of bucks had no significant (p > 0.05) variations during the dry and rainy seasons. However, temperatures of left and right skin testis were higher (p < 0.05) during the dry as compared to the rainy season. Expression of three proteins (lysine-specific demethylase 5D, adenosine triphosphate (ATP) synthase subunit d, and radial spoke head protein 9 homolog) in sperm membrane were more intense in rainy season and only one protein (cytosol aminopeptidase) had greater expression in the dry season of the year. Our results show that mechanisms of testicular thermoregulation of Saanen bucks did not prevent a decrease in seminal parameters during the dry season. This deterioration may be related to reduced expression of proteins associated with important functions in sperm membrane.
Collapse
Affiliation(s)
- M F van Tilburg
- Department of Animal Science, Federal University of Ceará, Av. Mister Hull S/N, Campus Pici, Fortaleza, CE, Brazil, 60021-970
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Lin H, Dutcher SK. Genetic and genomic approaches to identify genes involved in flagellar assembly in Chlamydomonas reinhardtii. Methods Cell Biol 2015; 127:349-86. [PMID: 25837400 DOI: 10.1016/bs.mcb.2014.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Flagellar assembly requires intraflagellar transport of components from the cell body to the flagellar tip for assembly. The understanding of flagellar assembly has been aided by the ease of biochemistry and the availability of mutants in the unicellular green alga, Chlamydomonas reinhardtii. In this chapter, we discuss means to identify genes involved in these processes using forward and reverse genetics. In particular, the ease and low cost of whole genome sequencing (WGS) will help to make gene identification easier and promote the understanding of this important process.
Collapse
Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University, St. Louis, MO, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University, St. Louis, MO, USA.
| |
Collapse
|
25
|
Vasudevan KK, Song K, Alford LM, Sale WS, Dymek EE, Smith EF, Hennessey T, Joachimiak E, Urbanska P, Wloga D, Dentler W, Nicastro D, Gaertig J. FAP206 is a microtubule-docking adapter for ciliary radial spoke 2 and dynein c. Mol Biol Cell 2014; 26:696-710. [PMID: 25540426 PMCID: PMC4325840 DOI: 10.1091/mbc.e14-11-1506] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Radial spokes are conserved macromolecular complexes that are essential for ciliary motility. Little is known about the assembly and functions of the three individual radial spokes, RS1, RS2, and RS3. In Tetrahymena, a conserved ciliary protein, FAP206, docks RS2 and dynein c to the doublet microtubule. Radial spokes are conserved macromolecular complexes that are essential for ciliary motility. A triplet of three radial spokes, RS1, RS2, and RS3, repeats every 96 nm along the doublet microtubules. Each spoke has a distinct base that docks to the doublet and is linked to different inner dynein arms. Little is known about the assembly and functions of individual radial spokes. A knockout of the conserved ciliary protein FAP206 in the ciliate Tetrahymena resulted in slow cell motility. Cryo–electron tomography showed that in the absence of FAP206, the 96-nm repeats lacked RS2 and dynein c. Occasionally, RS2 assembled but lacked both the front prong of its microtubule base and dynein c, whose tail is attached to the front prong. Overexpressed GFP-FAP206 decorated nonciliary microtubules in vivo. Thus FAP206 is likely part of the front prong and docks RS2 and dynein c to the microtubule.
Collapse
Affiliation(s)
| | - Kangkang Song
- Department of Biology, Rosenstiel Center, Brandeis University, Waltham, MA 02454
| | - Lea M Alford
- Department of Cell Biology, Emory University, Atlanta, GA 30303
| | - Winfield S Sale
- Department of Cell Biology, Emory University, Atlanta, GA 30303
| | - Erin E Dymek
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Elizabeth F Smith
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755
| | - Todd Hennessey
- Department of Biological Sciences, State University of New York, Buffalo, NY 14260
| | - Ewa Joachimiak
- Department of Cell Biology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland Department of Animal Physiology, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland
| | - Paulina Urbanska
- Department of Cell Biology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - Dorota Wloga
- Department of Cell Biology, Nencki Institute of Experimental Biology, 02-093 Warsaw, Poland
| | - William Dentler
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045
| | - Daniela Nicastro
- Department of Biology, Rosenstiel Center, Brandeis University, Waltham, MA 02454
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA 30602
| |
Collapse
|
26
|
Cryo-electron tomography reveals ciliary defects underlying human RSPH1 primary ciliary dyskinesia. Nat Commun 2014; 5:5727. [PMID: 25473808 PMCID: PMC4267722 DOI: 10.1038/ncomms6727] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/30/2014] [Indexed: 12/21/2022] Open
Abstract
Cilia play essential roles in normal human development and health; cilia dysfunction results in diseases such as primary ciliary dyskinesia (PCD). Despite their importance, the native structure of human cilia is unknown, and structural defects in the cilia of patients are often undetectable or remain elusive because of heterogeneity. Here we develop an approach that enables visualization of human (patient) cilia at high-resolution using cryo-electron tomography of samples obtained noninvasively by nasal scrape biopsy. We present the native 3D structures of normal and PCD-causing RSPH1-mutant human respiratory cilia in unprecedented detail; this allows comparisons of cilia structure across evolutionarily distant species and reveals the previously unknown primary defect and the heterogeneous secondary defects in RSPH1-mutant cilia. Our data provide evidence for structural and functional heterogeneity in radial spokes, suggest a mechanism for the milder RSPH1 PCD phenotype and demonstrate that cryo-electron tomography can be applied to human disease by directly imaging patient samples.
Collapse
|
27
|
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.
Collapse
|
28
|
Alford LM, Mattheyses AL, Hunter EL, Lin H, Dutcher SK, Sale WS. The Chlamydomonas mutant pf27 reveals novel features of ciliary radial spoke assembly. Cytoskeleton (Hoboken) 2014; 70:804-18. [PMID: 24124175 DOI: 10.1002/cm.21144] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/10/2013] [Accepted: 09/12/2013] [Indexed: 01/05/2023]
Abstract
To address the mechanisms of ciliary radial spoke assembly, we took advantage of the Chlamydomonas pf27 mutant. The radial spokes that assemble in pf27 are localized to the proximal quarter of the axoneme, but otherwise are fully assembled into 20S radial spoke complexes competent to bind spokeless axonemes in vitro. Thus, pf27 is not defective in radial spoke assembly or docking to the axoneme. Rather, our results suggest that pf27 is defective in the transport of spoke complexes. During ciliary regeneration in pf27, radial spoke assembly occurs asynchronously from other axonemal components. In contrast, during ciliary regeneration in wild-type Chlamydomonas, radial spokes and other axonemal components assemble concurrently as the axoneme grows. Complementation in temporary dikaryons between wild-type and pf27 reveals rescue of radial spoke assembly that begins at the distal tip, allowing further assembly to proceed from tip to base of the axoneme. Notably, rescued assembly of radial spokes occurred independently of the established proximal radial spokes in pf27 axonemes in dikaryons. These results reveal that 20S radial spokes can assemble proximally in the pf27 cilium but as the cilium lengthens, spoke assembly requires transport. We postulate that PF27 encodes an adaptor or modifier protein required for radial spoke–IFT interaction.
Collapse
|
29
|
Oda T, Yanagisawa H, Yagi T, Kikkawa M. Mechanosignaling between central apparatus and radial spokes controls axonemal dynein activity. ACTA ACUST UNITED AC 2014; 204:807-19. [PMID: 24590175 PMCID: PMC3941055 DOI: 10.1083/jcb.201312014] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Nonspecific intermolecular collision between the central pair apparatus and radial spokes underlies a mechanosensing mechanism that regulates dynein activity in Chlamydomonas flagella. Cilia/flagella are conserved organelles that generate fluid flow in eukaryotes. The bending motion of flagella requires concerted activity of dynein motors. Although it has been reported that the central pair apparatus (CP) and radial spokes (RSs) are important for flagellar motility, the molecular mechanism underlying CP- and RS-mediated dynein regulation has not been identified. In this paper, we identified nonspecific intermolecular collision between CP and RS as one of the regulatory mechanisms for flagellar motility. By combining cryoelectron tomography and motility analyses of Chlamydomonasreinhardtii flagella, we show that binding of streptavidin to RS heads paralyzed flagella. Moreover, the motility defect in a CP projection mutant could be rescued by the addition of exogenous protein tags on RS heads. Genetic experiments demonstrated that outer dynein arms are the major downstream effectors of CP- and RS-mediated regulation of flagellar motility. These results suggest that mechanosignaling between CP and RS regulates dynein activity in eukaryotic flagella.
Collapse
Affiliation(s)
- Toshiyuki Oda
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | |
Collapse
|
30
|
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.
Collapse
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
| |
Collapse
|
31
|
Dutcher SK. The awesome power of dikaryons for studying flagella and basal bodies in Chlamydomonas reinhardtii. Cytoskeleton (Hoboken) 2013; 71:79-94. [PMID: 24272949 DOI: 10.1002/cm.21157] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 11/19/2013] [Indexed: 11/08/2022]
Abstract
Cilia/flagella and basal bodies/centrioles play key roles in human health and homeostasis. Among the organisms used to study these microtubule-based organelles, the green alga Chlamydomonas reinhardtii has several advantages. One is the existence of a temporary phase of the life cycle, termed the dikaryon. These cells are formed during mating when the cells fuse and the behavior of flagella from two genetically distinguishable parents can be observed. During this stage, the cytoplasms mix allowing for a defect in the flagella of one parent to be rescued by proteins from the other parent. This offers the unique advantage of adding back wild-type gene product or labeled protein at endogenous levels that can used to monitor various flagellar and basal body phenotypes. Mutants that show rescue and ones that fail to show rescue are both informative about the nature of the flagella and basal body defects. When rescue occurs, it can be used to determine the mutant gene product and to follow the temporal and spatial patterns of flagellar assembly. This review describes many examples of insights into basal body and flagellar proteins' function and assembly that have been discovered using dikaryons and discusses the potential for further analyses.
Collapse
Affiliation(s)
- Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
| |
Collapse
|
32
|
Lin H, Miller ML, Granas DM, Dutcher SK. Whole genome sequencing identifies a deletion in protein phosphatase 2A that affects its stability and localization in Chlamydomonas reinhardtii. PLoS Genet 2013; 9:e1003841. [PMID: 24086163 PMCID: PMC3784568 DOI: 10.1371/journal.pgen.1003841] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/13/2013] [Indexed: 11/19/2022] Open
Abstract
Whole genome sequencing is a powerful tool in the discovery of single nucleotide polymorphisms (SNPs) and small insertions/deletions (indels) among mutant strains, which simplifies forward genetics approaches. However, identification of the causative mutation among a large number of non-causative SNPs in a mutant strain remains a big challenge. In the unicellular biflagellate green alga Chlamydomonas reinhardtii, we generated a SNP/indel library that contains over 2 million polymorphisms from four wild-type strains, one highly polymorphic strain that is frequently used in meiotic mapping, ten mutant strains that have flagellar assembly or motility defects, and one mutant strain, imp3, which has a mating defect. A comparison of polymorphisms in the imp3 strain and the other 15 strains allowed us to identify a deletion of the last three amino acids, Y313F314L315, in a protein phosphatase 2A catalytic subunit (PP2A3) in the imp3 strain. Introduction of a wild-type HA-tagged PP2A3 rescues the mutant phenotype, but mutant HA-PP2A3 at Y313 or L315 fail to rescue. Our immunoprecipitation results indicate that the Y313, L315, or YFLΔ mutations do not affect the binding of PP2A3 to the scaffold subunit, PP2A-2r. In contrast, the Y313, L315, or YFLΔ mutations affect both the stability and the localization of PP2A3. The PP2A3 protein is less abundant in these mutants and fails to accumulate in the basal body area as observed in transformants with either wild-type HA-PP2A3 or a HA-PP2A3 with a V310T change. The accumulation of HA-PP2A3 in the basal body region disappears in mated dikaryons, which suggests that the localization of PP2A3 may be essential to the mating process. Overall, our results demonstrate that the terminal YFL tail of PP2A3 is important in the regulation on Chlamydomonas mating.
Collapse
Affiliation(s)
- Huawen Lin
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Michelle L. Miller
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - David M. Granas
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Center for Genomic Sciences and System Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Susan K. Dutcher
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
| |
Collapse
|
33
|
Sivadas P, Dienes JM, St Maurice M, Meek WD, Yang P. A flagellar A-kinase anchoring protein with two amphipathic helices forms a structural scaffold in the radial spoke complex. ACTA ACUST UNITED AC 2013; 199:639-51. [PMID: 23148234 PMCID: PMC3494852 DOI: 10.1083/jcb.201111042] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amphipathic helices in the A-kinase anchoring protein RSP3 bind to spoke proteins involved in the assembly and modulation of the flagellar radial spoke complex, expanding the repertoire of these versatile helical protein motifs. A-kinase anchoring proteins (AKAPs) contain an amphipathic helix (AH) that binds the dimerization and docking (D/D) domain, RIIa, in cAMP-dependent protein kinase A (PKA). Many AKAPs were discovered solely based on the AH–RIIa interaction in vitro. An RIIa or a similar Dpy-30 domain is also present in numerous diverged molecules that are implicated in critical processes as diverse as flagellar beating, membrane trafficking, histone methylation, and stem cell differentiation, yet these molecules remain poorly characterized. Here we demonstrate that an AKAP, RSP3, forms a dimeric structural scaffold in the flagellar radial spoke complex, anchoring through two distinct AHs, the RIIa and Dpy-30 domains, in four non-PKA spoke proteins involved in the assembly and modulation of the complex. Interestingly, one AH can bind both RIIa and Dpy-30 domains in vitro. Thus, AHs and D/D domains constitute a versatile yet potentially promiscuous system for localizing various effector mechanisms. These results greatly expand the current concept about anchoring mechanisms and AKAPs.
Collapse
Affiliation(s)
- Priyanka Sivadas
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | | | | | | | | |
Collapse
|
34
|
Tam LW, Ranum PT, Lefebvre PA. CDKL5 regulates flagellar length and localizes to the base of the flagella in Chlamydomonas. Mol Biol Cell 2013; 24:588-600. [PMID: 23283985 PMCID: PMC3583663 DOI: 10.1091/mbc.e12-10-0718] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Two mutations in LF5, which encodes a protein kinase orthologous to human CDKL5, cause abnormally long flagella in Chlamydomonas. The localization of LF5p to the very proximal region of flagella in WT cells is regulated by three other LF gene products, which make up the cytoplasmic length regulatory complex. The length of Chlamydomonas flagella is tightly regulated. Mutations in four genes—LF1, LF2, LF3, and LF4—cause cells to assemble flagella up to three times wild-type length. LF2 and LF4 encode protein kinases. Here we describe a new gene, LF5, in which null mutations cause cells to assemble flagella of excess length. The LF5 gene encodes a protein kinase very similar in sequence to the protein kinase CDKL5. In humans, mutations in this kinase cause a severe form of juvenile epilepsy. The LF5 protein localizes to a unique location: the proximal 1 μm of the flagella. The proximal localization of the LF5 protein is lost when genes that make up the proteins in the cytoplasmic length regulatory complex (LRC)—LF1, LF2, and LF3—are mutated. In these mutants LF5p becomes localized either at the distal tip of the flagella or along the flagellar length, indicating that length regulation involves, at least in part, control of LF5p localization by the LRC.
Collapse
Affiliation(s)
- Lai-Wa Tam
- Department of Plant Biology, University of Minnesota, St. Paul, MN 55108, USA
| | | | | |
Collapse
|
35
|
Mizuno N, Taschner M, Engel BD, Lorentzen E. Structural studies of ciliary components. J Mol Biol 2012; 422:163-80. [PMID: 22683354 PMCID: PMC3426769 DOI: 10.1016/j.jmb.2012.05.040] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/23/2012] [Accepted: 05/24/2012] [Indexed: 11/24/2022]
Abstract
Cilia are organelles found on most eukaryotic cells, where they serve important functions in motility, sensory reception, and signaling. Recent advances in electron tomography have facilitated a number of ultrastructural studies of ciliary components that have significantly improved our knowledge of cilium architecture. These studies have produced nanometer-resolution structures of axonemal dynein complexes, microtubule doublets and triplets, basal bodies, radial spokes, and nexin complexes. In addition to these electron tomography studies, several recently published crystal structures provide insights into the architecture and mechanism of dynein as well as the centriolar protein SAS-6, important for establishing the 9-fold symmetry of centrioles. Ciliary assembly requires intraflagellar transport (IFT), a process that moves macromolecules between the tip of the cilium and the cell body. IFT relies on a large 20-subunit protein complex that is thought to mediate the contacts between ciliary motor and cargo proteins. Structural investigations of IFT complexes are starting to emerge, including the first three-dimensional models of IFT material in situ, revealing how IFT particles organize into larger train-like arrays, and the high-resolution structure of the IFT25/27 subcomplex. In this review, we cover recent advances in the structural and mechanistic understanding of ciliary components and IFT complexes.
Collapse
Key Words
- 2d, two‐dimensional
- 3d, three‐dimensional
- dic, differential interference contrast
- drc, dynein regulatory complex
- em, electron microscopy
- et, electron tomography
- ida, inner dynein arm
- ift, intraflagellar transport
- mt, microtubule
- mtbd, microtubule binding domain
- oda, outer dynein arm
- rs, radial spoke
- rsp, radial spoke protein
- cilium
- intraflagellar transport
- electron tomography
- ift complex
- flagellum
Collapse
Affiliation(s)
- Naoko Mizuno
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Michael Taschner
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Benjamin D. Engel
- Department of Molecular Structural Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Esben Lorentzen
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| |
Collapse
|
36
|
The DPY-30 domain and its flanking sequence mediate the assembly and modulation of flagellar radial spoke complexes. Mol Cell Biol 2012; 32:4012-24. [PMID: 22851692 DOI: 10.1128/mcb.06602-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RIIa is known as the dimerization and docking (D/D) domain of the cyclic AMP (cAMP)-dependent protein kinase. However, numerous molecules, including radial spoke protein 2 (RSP2) in Chlamydomonas flagella, also contain an RIIa or a similar DPY-30 domain. To elucidate new roles of D/D domain-containing proteins, we investigated a panel of RSP2 mutants. An RSP2 mutant had paralyzed flagella defective in RSP2 and multiple subunits near the spokehead. New transgenic strains lacking only the DPY-30 domain in RSP2 were also paralyzed. In contrast, motility was restored in strains that lacked only RSP2's calmodulin-binding C-terminal region. These cells swam normally in dim light but could not maintain typical swimming trajectories under bright illumination. In both deletion transgenic strains, the subunits near the spokehead were restored, but their firm attachment to the spokestalk required the DPY-30 domain. We postulate that the DPY-30-helix dimer is a conserved two-prong linker, required for normal motility, organizing duplicated subunits in the radial spoke stalk and formation of a symmetrical spokehead. Further, the dispensable calmodulin-binding region appears to fine-tune the spokehead for regulation of "steering" motility in the green algae. Thus, in general, D/D domains may function to localize molecular modules for both the assembly and modulation of macromolecular complexes.
Collapse
|
37
|
Gupta A, Diener DR, Sivadas P, Rosenbaum JL, Yang P. The versatile molecular complex component LC8 promotes several distinct steps of flagellar assembly. ACTA ACUST UNITED AC 2012; 198:115-26. [PMID: 22753897 PMCID: PMC3392930 DOI: 10.1083/jcb.201111041] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
LC8 is present in various molecular complexes. However, its role in these complexes remains unclear. We discovered that although LC8 is a subunit of the radial spoke (RS) complex in Chlamydomonas flagella, it was undetectable in the RS precursor that is converted into the mature RS at the tip of elongating axonemes. Interestingly, LC8 dimers bound in tandem to the N-terminal region of a spoke phosphoprotein, RS protein 3 (RSP3), that docks RSs to axonemes. LC8 enhanced the binding of RSP3 N-terminal fragments to purified axonemes. Likewise, the N-terminal fragments extracted from axonemes contained LC8 and putative spoke-docking proteins. Lastly, perturbations of RSP3's LC8-binding sites resulted in asynchronous flagella with hypophosphorylated RSP3 and defective associations between LC8, RSs, and axonemes. We propose that at the tip of flagella, an array of LC8 dimers binds to RSP3 in RS precursors, triggering phosphorylation, stalk base formation, and axoneme targeting. These multiple effects shed new light on fundamental questions about LC8-containing complexes and axoneme assembly.
Collapse
Affiliation(s)
- Anjali Gupta
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA
| | | | | | | | | |
Collapse
|
38
|
Heuser T, Dymek EE, Lin J, Smith EF, Nicastro D. The CSC connects three major axonemal complexes involved in dynein regulation. Mol Biol Cell 2012; 23:3143-55. [PMID: 22740634 PMCID: PMC3418309 DOI: 10.1091/mbc.e12-05-0357] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This study reveals the 3D structure of the CSC and its connections to three major axonemal complexes involved in dynein regulation, including the distal radial spoke and the nexin-DRC. The findings corroborate radial spoke heterogeneity and suggest a unique role for the distal spoke in calcium-mediated signal transduction and flagellar motility. Motile cilia and flagella are highly conserved organelles that play important roles in human health and development. We recently discovered a calmodulin- and spoke-associated complex (CSC) that is required for wild-type motility and for the stable assembly of a subset of radial spokes. Using cryo–electron tomography, we present the first structure-based localization model of the CSC. Chlamydomonas flagella have two full-length radial spokes, RS1 and RS2, and a shorter RS3 homologue, the RS3 stand-in (RS3S). Using newly developed techniques for analyzing samples with structural heterogeneity, we demonstrate that the CSC connects three major axonemal complexes involved in dynein regulation: RS2, the nexin–dynein regulatory complex (N-DRC), and RS3S. These results provide insights into how signals from the radial spokes may be transmitted to the N-DRC and ultimately to the dynein motors. Our results also indicate that although structurally very similar, RS1 and RS2 likely serve different functions in regulating flagellar motility.
Collapse
Affiliation(s)
- Thomas Heuser
- Biology Department, Rosenstiel Center, Brandeis University, Waltham, MA 02454, USA
| | | | | | | | | |
Collapse
|
39
|
Lin J, Heuser T, Carbajal-González BI, Song K, Nicastro D. The structural heterogeneity of radial spokes in cilia and flagella is conserved. Cytoskeleton (Hoboken) 2012; 69:88-100. [PMID: 22170736 DOI: 10.1002/cm.21000] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/02/2011] [Accepted: 12/05/2011] [Indexed: 01/05/2023]
Abstract
Radial spokes (RSs) are ubiquitous components of motile cilia and flagella and play an essential role in transmitting signals that regulate the activity of the dynein motors, and thus ciliary and flagellar motility. In some organisms, the 96 nm axonemal repeat unit contains only a pair of spokes, RS1 and RS2, while most organisms have spoke triplets with an additional spoke RS3. The spoke pairs in Chlamydomonas flagella have been well characterized, while spoke triplets have received less attention. Here, we used cryoelectron tomography and subtomogram averaging to visualize the three-dimensional structure of spoke triplets in Strongylocentrotus purpuratus (sea urchin) sperm flagella in unprecedented detail. Only small differences were observed between RS1 and RS2, but the structure of RS3 was surprisingly unique and structurally different from the other two spokes. We observed novel doublet specific features that connect RS2, RS3, and the nexin-dynein regulatory complex, three key ciliary and flagellar structures. The distribution of these doublet specific structures suggests that they could be important for establishing the asymmetry of dynein activity required for the oscillatory movement of cilia and flagella. Surprisingly, a comparison with other organisms demonstrated both that this considerable RS heterogeneity is conserved and that organisms with RS pairs contain the basal part of RS3. This conserved RS heterogeneity may also reflect functional differences between the spokes and their involvement in regulating ciliary and flagellar motility.
Collapse
Affiliation(s)
- Jianfeng Lin
- Department of Biology, Rosenstiel Center, MS029, Brandeis University, Waltham, Massachusetts 02454-9110, USA
| | | | | | | | | |
Collapse
|
40
|
Whole-Genome Sequencing to Identify Mutants and Polymorphisms in Chlamydomonas reinhardtii. G3-GENES GENOMES GENETICS 2012; 2:15-22. [PMID: 22384377 PMCID: PMC3276182 DOI: 10.1534/g3.111.000919] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 10/31/2011] [Indexed: 12/26/2022]
Abstract
Whole-genome sequencing (WGS) provides a new platform for the identification of mutations that produce a mutant phenotype. We used Illumina sequencing to identify the mutational profile of three Chlamydomonas reinhardtii mutant strains. The three strains have more than 38,000 changes from the reference genome. NG6 is aflagellate and maps to 269 kb with only one nonsynonymous change; the V(12)E mutation falls in the FLA8 gene. Evidence that NG6 is a fla8 allele comes from swimming revertants that are either true or pseudorevertants. NG30 is aflagellate and maps to 458 kb that has six nonsynonomous changes. Evidence that NG30 has a causative nonsense allele in IFT80 comes from rescue of the nonswimming phenotype with a fragment bearing only this gene. This gene has been implicated in Jeune asphyxiating thoracic dystrophy. Electron microscopy of ift80-1 (NG30) shows a novel basal body phenotype. A bar or cap is observed over the distal end of the transition zone, which may be an intermediate in preparing the basal body for flagellar assembly. In the acetate-requiring mutant ac17, we failed to find a nonsynonymous change in the 676 kb mapped region, which is incompletely assembled. In these strains, 43% of the changes occur on two of the 17 chromosomes. The excess on chromosome 6 surrounds the mating-type locus, which has numerous rearrangements and suppressed recombination, and the changes extend beyond the mating-type locus. Unexpectedly, chromosome 16 shows an unexplained excess of single nucleotide polymorphisms and indels. Overall, WGS in combination with limited mapping allows fast and accurate identification of point mutations in Chlamydomonas.
Collapse
|
41
|
Barber CF, Heuser T, Carbajal-González BI, Botchkarev VV, Nicastro D. Three-dimensional structure of the radial spokes reveals heterogeneity and interactions with dyneins in Chlamydomonas flagella. Mol Biol Cell 2011; 23:111-20. [PMID: 22072792 PMCID: PMC3248890 DOI: 10.1091/mbc.e11-08-0692] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Cryo–electron tomography of Chlamydomonas flagella reveals previously uncharacterized features of the radial spokes, including structural heterogeneity and direct interactions with dyneins and between the spoke heads. A “radial spoke 3 stand-in” occupies what would be the site of a third spoke in organisms with spoke triplets. Radial spokes (RSs) play an essential role in the regulation of axonemal dynein activity and thus of ciliary and flagellar motility. However, few details are known about the complexes involved. Using cryo–electron tomography and subtomogram averaging, we visualized the three-dimensional structure of the radial spokes in Chlamydomonas flagella in unprecedented detail. Unlike many other species, Chlamydomonas has only two spokes per axonemal repeat, RS1 and RS2. Our data revealed previously uncharacterized features, including two-pronged spoke bases that facilitate docking to the doublet microtubules, and that inner dyneins connect directly to the spokes. Structures of wild type and the headless spoke mutant pf17 were compared to define the morphology and boundaries of the head, including a direct RS1-to-RS2 interaction. Although the overall structures of the spokes are very similar, we also observed some differences, corroborating recent findings about heterogeneity in the docking of RS1 and RS2. In place of a third radial spoke we found an uncharacterized, shorter electron density named “radial spoke 3 stand-in,” which structurally bears no resemblance to RS1 and RS2 and is unaltered in the pf17 mutant. These findings demonstrate that radial spokes are heterogeneous in structure and may play functionally distinct roles in axoneme regulation.
Collapse
Affiliation(s)
- Cynthia F Barber
- Biology Department, Rosenstiel Center, Brandeis University, Waltham, MA 02454, USA
| | | | | | | | | |
Collapse
|
42
|
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.
Collapse
Affiliation(s)
- Gaia Pigino
- Biomolecular Research Laboratory, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland
| | | | | | | | | | | |
Collapse
|
43
|
Dymek EE, Heuser T, Nicastro D, Smith EF. The CSC is required for complete radial spoke assembly and wild-type ciliary motility. Mol Biol Cell 2011; 22:2520-31. [PMID: 21613541 PMCID: PMC3135477 DOI: 10.1091/mbc.e11-03-0271] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Structural and functional analyses of artificial micro RNA (amiRNA) mutants reveal that the CSC plays a role not only in generating wild-type motility, but also in assembly of at least a subset of radial spokes. This study also produced the unexpected finding that, contrary to current belief, the radial spokes may not be homogeneous. The ubiquitous calcium binding protein, calmodulin (CaM), plays a major role in regulating the motility of all eukaryotic cilia and flagella. We previously identified a CaM and Spoke associated Complex (CSC) and provided evidence that this complex mediates regulatory signals between the radial spokes and dynein arms. We have now used an artificial microRNA (amiRNA) approach to reduce expression of two CSC subunits in Chlamydomonas. For all amiRNA mutants, the entire CSC is lacking or severely reduced in flagella. Structural studies of mutant axonemes revealed that assembly of radial spoke 2 is defective. Furthermore, analysis of both flagellar beating and microtubule sliding in vitro demonstrates that the CSC plays a critical role in modulating dynein activity. Our results not only indicate that the CSC is required for spoke assembly and wild-type motility, but also provide evidence for heterogeneity among the radial spokes.
Collapse
Affiliation(s)
- Erin E Dymek
- Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA
| | | | | | | |
Collapse
|
44
|
Wirschell M, Yamamoto R, Alford L, Gokhale A, Gaillard A, Sale WS. Regulation of ciliary motility: conserved protein kinases and phosphatases are targeted and anchored in the ciliary axoneme. Arch Biochem Biophys 2011; 510:93-100. [PMID: 21513695 DOI: 10.1016/j.abb.2011.04.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 04/05/2011] [Accepted: 04/06/2011] [Indexed: 12/31/2022]
Abstract
Recent evidence has revealed that the dynein motors and highly conserved signaling proteins are localized within the ciliary 9+2 axoneme. One key mechanism for regulation of motility is phosphorylation. Here, we review diverse evidence, from multiple experimental organisms, that ciliary motility is regulated by phosphorylation/dephosphorylation of the dynein arms through kinases and phosphatases that are anchored immediately adjacent to their axonemal substrates.
Collapse
Affiliation(s)
- Maureen Wirschell
- Emory University School of Medicine, Department of Cell Biology, Atlanta, GA 30322, USA.
| | | | | | | | | | | |
Collapse
|
45
|
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.
Collapse
Affiliation(s)
- Takahiro Kohno
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
| | | | | | | | | |
Collapse
|
46
|
Structure-function analysis of dynein light chain 1 identifies viable motility mutants in bloodstream-form Trypanosoma brucei. EUKARYOTIC CELL 2011; 10:884-94. [PMID: 21378260 DOI: 10.1128/ec.00298-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The flagellum of Trypanosoma brucei is an essential and multifunctional organelle that is receiving increasing attention as a potential drug target and as a system for studying flagellum biology. RNA interference (RNAi) knockdown is widely used to test the requirement for a protein in flagellar motility and has suggested that normal flagellar motility is essential for viability in bloodstream-form trypanosomes. However, RNAi knockdown alone provides limited functional information because the consequence is often loss of a multiprotein complex. We therefore developed an inducible system that allows functional analysis of point mutations in flagellar proteins in T. brucei. Using this system, we identified point mutations in the outer dynein light chain 1 (LC1) that allow stable assembly of outer dynein motors but do not support propulsive motility. In procyclic-form trypanosomes, the phenotype of LC1 mutants with point mutations differs from the motility and structural defects of LC1 knockdowns, which lack the outer-arm dynein motor. Thus, our results distinguish LC1-specific functions from broader functions of outer-arm dynein. In bloodstream-form trypanosomes, LC1 knockdown blocks cell division and is lethal. In contrast, LC1 point mutations cause severe motility defects without affecting viability, indicating that the lethal phenotype of LC1 RNAi knockdown is not due to defective motility. Our results demonstrate for the first time that normal motility is not essential in bloodstream-form T. brucei and that the presumed connection between motility and viability is more complex than might be interpreted from knockdown studies alone. These findings open new avenues for dissecting mechanisms of flagellar protein function and provide an important step in efforts to exploit the potential of the flagellum as a therapeutic target in African sleeping sickness.
Collapse
|
47
|
Wei M, Sivadas P, Owen HA, Mitchell DR, Yang P. Chlamydomonas mutants display reversible deficiencies in flagellar beating and axonemal assembly. Cytoskeleton (Hoboken) 2010; 67:71-80. [PMID: 20169531 PMCID: PMC2835312 DOI: 10.1002/cm.20422] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 10/14/2009] [Indexed: 11/12/2022]
Abstract
Axonemal complexes in flagella are largely prepackaged in the cell body. As such, one mutation often results in the absence of the co-assembled components and permanent motility deficiencies. For example, a Chlamydomonas mutant defective in RSP4 in the radial spoke (RS), which is critical for bend propagation, has paralyzed flagella that also lack the paralogue RSP6 and three additional RS proteins. Intriguingly, recent studies showed that several mutant strains contain a mixed population of swimmers and paralyzed cells despite their identical genetic background. Here we report a cause underlying these variations. Two new mutants lacking RSP6 swim processively and other components appear normally assembled in early log phase indicating that, unlike RSP4, this paralogue is dispensable. However, swimmers cannot maintain the typical helical trajectory and reactivated cell models tend to spin. Interestingly the motile fraction and the spokehead content dwindle during stationary phase. These results suggest that (1) intact RS is critical for maintaining the rhythm of oscillatory beating and thus the helical trajectory; (2) assembly of the axonemal complex with subtle defects is less efficient and the inefficiency is accentuated in compromised conditions, leading to reversible dyskinesia. Consistently, several organisms only possess one RSP4/6 gene. Gene duplication in Chlamydomonas enhances RS assembly to maintain optimal motility in various environments.
Collapse
Affiliation(s)
- Mei Wei
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
| | - Priyanka Sivadas
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
| | - Heather A. Owen
- Department of Biological Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave, Milwaukee, WI 53211
| | - David R. Mitchell
- Department of Cell and Developmental Biology, Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, 530 N. 15 St. Milwaukee, WI 53233
| |
Collapse
|
48
|
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]
|
49
|
Abstract
The 9+2 axoneme that mediates the highly controlled oscillatory beating of cilia and flagella is an elaborate supramolecular complex. Proteomics and genomics have revealed more than 400 distinct polypeptides that presumably are built into axonemal subcomplexes for specific tasks. However, only a handful of proteins can be assigned to the most prominent structural modules visible by electron microscopy. Much less is known about the function and mechanism of individual molecules and complexes. Isolation of intact complexes will hasten discoveries and open the door to a wide range of analyses as showcased by axonemal dynein motors. However, many axonemal components, such as the radial spoke complex, either are not extracted by conditions that solubilize axonemal dynein or at best are only partially released. This chapter discusses strategies and methods to circumvent this problem in order to characterize radial spokes. With appropriate modifications, the lessons learned from the radial spoke complex may be applicable to other axonemal complexes.
Collapse
|
50
|
Yang P, Yang C, Wirschell M, Davis S. Novel LC8 mutations have disparate effects on the assembly and stability of flagellar complexes. J Biol Chem 2009; 284:31412-21. [PMID: 19696030 DOI: 10.1074/jbc.m109.050666] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
LC8 functions as a dimer crucial for a variety of molecular motors and non-motor complexes. Emerging models, founded on structural studies, suggest that the LC8 dimer promotes the stability and refolding of dimeric target proteins in molecular complexes, and its interactions with selective target proteins, including dynein subunits, is regulated by LC8 phosphorylation, which is proposed to prevent LC8 dimerization. To test these hypotheses in vivo, we determine the impacts of two new LC8 mutations on the assembly and stability of defined LC8-containing complexes in Chlamydomonas flagella. The three types of dyneins and the radial spoke are disparately affected by dimeric LC8 with a C-terminal extension. The defects include the absence of specific subunits, complex instability, and reduced incorporation into the axonemal super complex. Surprisingly, a phosphomimetic LC8 mutation, which is largely monomeric in vitro, is still dimeric in vivo and does not significantly change flagellar generation and motility. The differential defects in these flagellar complexes support the structural model and indicate that modulation of target proteins by LC8 leads to the proper assembly of complexes and ultimately higher level complexes. Furthermore, the ability of flagellar complexes to incorporate the phosphomimetic LC8 protein and the modest defects observed in the phosphomimetic LC8 mutant suggest that LC8 phosphorylation is not an effective mechanism for regulating molecular complexes.
Collapse
Affiliation(s)
- Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53233, USA.
| | | | | | | |
Collapse
|