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Hou Y, Zhao L, Kubo T, Cheng X, McNeill N, Oda T, Witman GB. Chlamydomonas FAP70 is a component of the previously uncharacterized ciliary central apparatus projection C2a. J Cell Sci 2021; 134:jcs258540. [PMID: 33988244 PMCID: PMC8272932 DOI: 10.1242/jcs.258540] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022] Open
Abstract
Cilia are essential organelles required for cell signaling and motility. Nearly all motile cilia have a '9+2' axoneme composed of nine outer doublet microtubules plus two central microtubules; the central microtubules together with their projections are termed the central apparatus (CA). In Chlamydomonas reinhardtii, a model organism for studying cilia, 30 proteins are known CA components, and ∼36 more are predicted to be CA proteins. Among the candidate CA proteins is the highly conserved FAP70 (CFAP70 in humans), which also has been reported to be associated with the doublet microtubules. Here, we determined by super-resolution structured illumination microscopy that FAP70 is located exclusively in the CA, and show by cryo-electron microscopy that its N-terminus is located at the base of the C2a projection of the CA. We also found that fap70-1 mutant axonemes lack most of the C2a projection. Mass spectrometry revealed that fap70-1 axonemes lack not only FAP70 but two other conserved candidate CA proteins, FAP65 (CFAP65 in humans) and FAP147 (MYCBPAP in humans). Finally, FAP65 and FAP147 co-immunoprecipitated with HA-tagged FAP70. Taken together, these data identify FAP70, FAP65 and FAP147 as the first defining components of the C2a projection.
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Affiliation(s)
- Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Lei Zhao
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - Xi Cheng
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Nathan McNeill
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medicine, University of Yamanashi, Chuo, Yamanashi 409-3898, Japan
| | - George B. Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655, USA
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Oda T, Yanagisawa H. Cryo-electron tomography of cardiac myofibrils reveals a 3D lattice spring within the Z-discs. Commun Biol 2020; 3:585. [PMID: 33067529 PMCID: PMC7567829 DOI: 10.1038/s42003-020-01321-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 09/25/2020] [Indexed: 01/29/2023] Open
Abstract
The Z-disc forms a boundary between sarcomeres, which constitute structural and functional units of striated muscle tissue. Actin filaments from adjacent sarcomeres are cross-bridged by α-actinin in the Z-disc, allowing transmission of tension across the myofibril. Despite decades of studies, the 3D structure of Z-disc has remained elusive due to the limited resolution of conventional electron microscopy. Here, we observed porcine cardiac myofibrils using cryo-electron tomography and reconstructed the 3D structures of the actin-actinin cross-bridging complexes within the Z-discs in relaxed and activated states. We found that the α-actinin dimers showed contraction-dependent swinging and sliding motions in response to a global twist in the F-actin lattice. Our observation suggests that the actin-actinin complex constitutes a molecular lattice spring, which maintains the integrity of the Z-disc during the muscle contraction cycle.
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Affiliation(s)
- Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medicine, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan.
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
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Thompson MC, Yeates TO, Rodriguez JA. Advances in methods for atomic resolution macromolecular structure determination. F1000Res 2020; 9:F1000 Faculty Rev-667. [PMID: 32676184 PMCID: PMC7333361 DOI: 10.12688/f1000research.25097.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/25/2020] [Indexed: 12/13/2022] Open
Abstract
Recent technical advances have dramatically increased the power and scope of structural biology. New developments in high-resolution cryo-electron microscopy, serial X-ray crystallography, and electron diffraction have been especially transformative. Here we highlight some of the latest advances and current challenges at the frontiers of atomic resolution methods for elucidating the structures and dynamical properties of macromolecules and their complexes.
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Affiliation(s)
- Michael C. Thompson
- Department of Chemistry and Chemical Biology, University of California, Merced, CA, USA
| | - Todd O. Yeates
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
| | - Jose A. Rodriguez
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA, USA
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Zhao L, Hou Y, Picariello T, Craige B, Witman GB. Proteome of the central apparatus of a ciliary axoneme. J Cell Biol 2019; 218:2051-2070. [PMID: 31092556 PMCID: PMC6548120 DOI: 10.1083/jcb.201902017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 04/13/2019] [Accepted: 04/17/2019] [Indexed: 12/15/2022] Open
Abstract
The central apparatus is an essential component of “9+2” cilia. Zhao et al. identify more than 40 new potential components of the central apparatus of Chlamydomonas. Many are conserved and will facilitate genetic screening of patients with a form of primary ciliary dyskinesia that is difficult to diagnose. Nearly all motile cilia have a “9+2” axoneme containing a central apparatus (CA), consisting of two central microtubules with projections, that is essential for motility. To date, only 22 proteins are known to be CA components. To identify new candidate CA proteins, we used mass spectrometry to compare axonemes of wild-type Chlamydomonas and a CA-less mutant. We identified 44 novel candidate CA proteins, of which 13 are conserved in humans. Five of the latter were studied more closely, and all five localized to the CA; therefore, most of the other candidates are likely to also be CA components. Our results reveal that the CA is far more compositionally complex than previously recognized and provide a greatly expanded knowledge base for studies to understand the architecture of the CA and how it functions. The discovery of the new conserved CA proteins will facilitate genetic screening to identify patients with a form of primary ciliary dyskinesia that has been difficult to diagnose.
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Affiliation(s)
- Lei Zhao
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Tyler Picariello
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - Branch Craige
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA
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Lechtreck KF, Mengoni I, Okivie B, Hilderhoff KB. In vivo analyses of radial spoke transport, assembly, repair and maintenance. Cytoskeleton (Hoboken) 2018; 75:352-362. [PMID: 30070024 DOI: 10.1002/cm.21457] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 01/15/2023]
Abstract
Radial spokes (RSs) are multiprotein complexes that regulate dynein activity. In the cell body, RS proteins (RSPs) are present in a 12S precursor, which enters the flagella and converts into the axoneme-bound 20S spokes consisting of a head and stalk. To study RS dynamics in vivo, we expressed fluorescent protein (FP)-tagged versions of the head protein RSP4 and the stalk protein RSP3 to rescue the corresponding Chlamydomonas mutants pf1, lacking spoke heads, and pf14, lacking RSs entirely. RSP3 and RSP4 mostly co-migrated by intraflagellar transport (IFT). The transport was elevated during flagellar assembly and IFT of RSP4-FP depended on RSP3. To study RS assembly independently of ciliogenesis, strains expressing FP-tagged RSPs were mated to untagged cells with, without, or with partial RSs. Tagged RSPs were incorporated in a spotted fashion along wild-type-derived flagella indicating an exchange of RSs. During the repair of pf1-derived axonemes, RSP4-FP is added onto the preexisting spoke stalks with little exchange of RSP3. Thus, RSP3 and RSP4 are transported together but appear to separate inside flagella during the repair of RSs. The 12S RS precursor encompassing both proteins could represent a transport form to ensure stoichiometric delivery of RSPs into flagella by IFT.
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Affiliation(s)
- Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | - Ilaria Mengoni
- Department of Cellular Biology, University of Georgia, Athens, Georgia
| | - Batare Okivie
- Department of Cellular Biology, University of Georgia, Athens, Georgia
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Kubo T, Hou Y, Cochran DA, Witman GB, Oda T. A microtubule-dynein tethering complex regulates the axonemal inner dynein f (I1). Mol Biol Cell 2018. [PMID: 29540525 PMCID: PMC5921573 DOI: 10.1091/mbc.e17-11-0689] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
FAP44 and FAP43/FAP244 form a complex that tethers the Inner dynein subspecies f to the microtubule in Chlamydomonas flagella. The tether complex regulates flagellar motility by restraining conformational change in the dynein motor. Motility of cilia/flagella is generated by a coordinated activity of thousands of dyneins. Inner dynein arms (IDAs) are particularly important for the formation of ciliary/flagellar waveforms, but the molecular mechanism of IDA regulation is poorly understood. Here we show using cryoelectron tomography and biochemical analyses of Chlamydomonas flagella that a conserved protein FAP44 forms a complex that tethers IDA f (I1 dynein) head domains to the A-tubule of the axonemal outer doublet microtubule. In wild-type flagella, IDA f showed little nucleotide-dependent movement except for a tilt in the f β head perpendicular to the microtubule-sliding direction. In the absence of the tether complex, however, addition of ATP and vanadate caused a large conformational change in the IDA f head domains, suggesting that the movement of IDA f is mechanically restricted by the tether complex. Motility defects in flagella missing the tether demonstrates the importance of the IDA f-tether interaction in the regulation of ciliary/flagellar beating.
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Affiliation(s)
- Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
| | - Yuqing Hou
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Deborah A Cochran
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - George B Witman
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi 409-3898, Japan
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Peabody JE, Shei RJ, Bermingham BM, Phillips SE, Turner B, Rowe SM, Solomon GM. Seeing cilia: imaging modalities for ciliary motion and clinical connections. Am J Physiol Lung Cell Mol Physiol 2018; 314:L909-L921. [PMID: 29493257 DOI: 10.1152/ajplung.00556.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The respiratory tract is lined with multiciliated epithelial cells that function to move mucus and trapped particles via the mucociliary transport apparatus. Genetic and acquired ciliopathies result in diminished mucociliary clearance, contributing to disease pathogenesis. Recent innovations in imaging technology have advanced our understanding of ciliary motion in health and disease states. Application of imaging modalities including transmission electron microscopy, high-speed video microscopy, and micron-optical coherence tomography could improve diagnostics and be applied for precision medicine. In this review, we provide an overview of ciliary motion, imaging modalities, and ciliopathic diseases of the respiratory system including primary ciliary dyskinesia, cystic fibrosis, chronic obstructive pulmonary disease, and idiopathic pulmonary fibrosis.
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Affiliation(s)
- Jacelyn E Peabody
- Department of Medicine, University of Alabama at Birmingham, Alabama.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama
| | - Ren-Jay Shei
- Department of Medicine, University of Alabama at Birmingham, Alabama.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama
| | | | - Scott E Phillips
- Department of Medicine, University of Alabama at Birmingham, Alabama
| | - Brett Turner
- Departments of Pediatrics and Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Alabama
| | - Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Alabama.,Departments of Pediatrics and Cell Developmental and Integrative Biology, University of Alabama at Birmingham, Alabama.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama
| | - George M Solomon
- Department of Medicine, University of Alabama at Birmingham, Alabama.,Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham , Birmingham, Alabama
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Kubo T, Oda T. Electrostatic interaction between polyglutamylated tubulin and the nexin-dynein regulatory complex regulates flagellar motility. Mol Biol Cell 2017. [PMID: 28637765 PMCID: PMC5555654 DOI: 10.1091/mbc.e17-05-0285] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The 3D localization of polyglutamylated tubulin in eukaryotic flagella is identified. Polyglutamylated tubulins are located on the interface between the microtubule and its cross-bridging structure, the N-DRC. Flagellar motility is regulated by electrostatic interaction between negatively charged tubulins and positively charged N-DRC. Tubulins undergo various posttranslational modifications. Among them, polyglutamylation is involved in the motility of eukaryotic flagella and the stability of the axonemal microtubules. However, it remains unclear where polyglutamylated tubulin localizes precisely within the axoneme and how tubulin polyglutamylation affects flagellar motility. In this study, we identified the three-dimensional localization of the polyglutamylated tubulin in Chlamydomonas flagella using antibody labeling and cryo–electron tomography. Polyglutamylated tubulins specifically located in close proximity to a microtubule-cross-bridging structure called the nexin–dynein regulatory complex (N-DRC). Because N-DRC is positively charged, we hypothesized that there is an electrostatic interaction between the polyglutamylated tubulin and the N-DRC, and therefore we mutated the amino acid sequences of DRC4 to modify the charge of the N-DRC. We found that both augmentation and reduction of the positive charge on DRC4 resulted in reduced flagellar motility. Moreover, reduced motility in a mutant with a structurally defective N-DRC was partially restored by increasing the positive charge on DRC4. These results clearly indicate that beating motion of flagella is maintained by the electrostatic cross-bridge formed between the negatively charged polyglutamylated tubulins and the positively charged N-DRC.
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Affiliation(s)
- Tomohiro Kubo
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Toshiyuki Oda
- Department of Anatomy and Structural Biology, Graduate School of Medical Science, University of Yamanashi, Yamanashi 409-3898, Japan
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