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Miyata H, Shimada K, Kaneda Y, Ikawa M. Development of functional spermatozoa in mammalian spermiogenesis. Development 2024; 151:dev202838. [PMID: 39036999 DOI: 10.1242/dev.202838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Infertility is a global health problem affecting one in six couples, with 50% of cases attributed to male infertility. Spermatozoa are male gametes, specialized cells that can be divided into two parts: the head and the flagellum. The head contains a vesicle called the acrosome that undergoes exocytosis and the flagellum is a motility apparatus that propels the spermatozoa forward and can be divided into two components, axonemes and accessory structures. For spermatozoa to fertilize oocytes, the acrosome and flagellum must be formed correctly. In this Review, we describe comprehensively how functional spermatozoa develop in mammals during spermiogenesis, including the formation of acrosomes, axonemes and accessory structures by focusing on analyses of mouse models.
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Affiliation(s)
- 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
| | - Yuki Kaneda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan
- The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
- Center for Infectious Disease Education and Research, Osaka University, Suita, Osaka 565-0871, Japan
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2
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Tani Y, Yanagisawa H, Yagi T, Kikkawa M. Structure and function of FAP47 in the central pair apparatus of Chlamydomonas flagella. Cytoskeleton (Hoboken) 2024. [PMID: 38899546 DOI: 10.1002/cm.21882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024]
Abstract
Motile cilia have a so-called "9 + 2" structure, which consists of nine doublet microtubules and a central pair apparatus. The central pair apparatus (CA) is thought to interact mechanically with radial spokes and to control the flagellar beating. Recently, the components of the CA have been identified by proteomic and genomic analyses. Still, the mechanism of how the CA contributes to ciliary motility has much to be revealed. Here, we focused on one CA component with a large molecular weight: FAP47, and its relationship with two other CA components with large molecular weight: HYDIN, and CPC1. The analyses of motility of the Chlamydomonas mutants revealed that in contrast to cpc1 or hydin, which swam more slowly than the wild type, fap47 cells displayed wild-type swimming velocity and flagellar beat frequency, yet interestingly, fap47 cells have phototaxis defects and swim straighter than the wild-type cells. Furthermore, the double mutant fap47cpc1 and fap47hydin showed significantly slower swimming than cpc1 and hydin cells, and the motility defect of fap47cpc1 was rescued to the cpc1 level with GFP-tagged FAP47, indicating that the lack of FAP47 makes the motility defect of cpc1 worse. Cryo-electron tomography demonstrated that the fap47 lacks a part of the C1-C2 bridge of CA. Taken together, these observations indicate that FAP47 maintains the structural stiffness of the CA, which is important for flagellar regulation.
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Affiliation(s)
- Yuma Tani
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruaki Yanagisawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Toshiki Yagi
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Hiroshima, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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3
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Jurisch-Yaksi N, Wachten D, Gopalakrishnan J. The neuronal cilium - a highly diverse and dynamic organelle involved in sensory detection and neuromodulation. Trends Neurosci 2024; 47:383-394. [PMID: 38580512 DOI: 10.1016/j.tins.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/04/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
Cilia are fascinating organelles that act as cellular antennae, sensing the cellular environment. Cilia gained significant attention in the late 1990s after their dysfunction was linked to genetic diseases known as ciliopathies. Since then, several breakthrough discoveries have uncovered the mechanisms underlying cilia biogenesis and function. Like most cells in the animal kingdom, neurons also harbor cilia, which are enriched in neuromodulatory receptors. Yet, how neuronal cilia modulate neuronal physiology and animal behavior remains poorly understood. By comparing ciliary biology between the sensory and central nervous systems (CNS), we provide new perspectives on the functions of cilia in brain physiology.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Department of Clinical and Molecular Medicine (IKOM), Faculty of Medicine and Health Science, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7491 Trondheim, Norway.
| | - Dagmar Wachten
- Department of Biophysical Imaging, Institute of Innate Immunity, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Jay Gopalakrishnan
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany; Institute for Human Genetics, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07740 Jena, Germany
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4
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Dai J, Ma M, Niu Q, Eisert RJ, Wang X, Das P, Lechtreck KF, Dutcher SK, Zhang R, Brown A. Mastigoneme structure reveals insights into the O-linked glycosylation code of native hydroxyproline-rich helices. Cell 2024; 187:1907-1921.e16. [PMID: 38552624 PMCID: PMC11015965 DOI: 10.1016/j.cell.2024.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 02/06/2024] [Accepted: 03/05/2024] [Indexed: 04/14/2024]
Abstract
Hydroxyproline-rich glycoproteins (HRGPs) are a ubiquitous class of protein in the extracellular matrices and cell walls of plants and algae, yet little is known of their native structures or interactions. Here, we used electron cryomicroscopy (cryo-EM) to determine the structure of the hydroxyproline-rich mastigoneme, an extracellular filament isolated from the cilia of the alga Chlamydomonas reinhardtii. The structure demonstrates that mastigonemes are formed from two HRGPs (a filament of MST1 wrapped around a single copy of MST3) that both have hyperglycosylated poly(hydroxyproline) helices. Within the helices, O-linked glycosylation of the hydroxyproline residues and O-galactosylation of interspersed serine residues create a carbohydrate casing. Analysis of the associated glycans reveals how the pattern of hydroxyproline repetition determines the type and extent of glycosylation. MST3 possesses a PKD2-like transmembrane domain that forms a heteromeric polycystin-like cation channel with PKD2 and SIP, explaining how mastigonemes are tethered to ciliary membranes.
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Affiliation(s)
- Jin Dai
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Meisheng Ma
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Qingwei Niu
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO, USA; Molecular Cell Biology (MCB) graduate program, Division of Biology & Biomedical Sciences, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Robyn J Eisert
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Poulomi Das
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Karl F Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St Louis, MO, USA
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis School of Medicine, St. Louis, MO, USA.
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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5
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Walton T, Doran MH, Brown A. Structural determination and modeling of ciliary microtubules. Acta Crystallogr D Struct Biol 2024; 80:220-231. [PMID: 38451206 PMCID: PMC10994176 DOI: 10.1107/s2059798324001815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 02/24/2024] [Indexed: 03/08/2024] Open
Abstract
The axoneme, a microtubule-based array at the center of every cilium, has been the subject of structural investigations for decades, but only recent advances in cryo-EM and cryo-ET have allowed a molecular-level interpretation of the entire complex to be achieved. The unique properties of the nine doublet microtubules and central pair of singlet microtubules that form the axoneme, including the highly decorated tubulin lattice and the docking of massive axonemal complexes, provide opportunities and challenges for sample preparation, 3D reconstruction and atomic modeling. Here, the approaches used for cryo-EM and cryo-ET of axonemes are reviewed, while highlighting the unique opportunities provided by the latest generation of AI-guided tools that are transforming structural biology.
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Affiliation(s)
- Travis Walton
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Matthew H. Doran
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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6
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Jamali K, Käll L, Zhang R, Brown A, Kimanius D, Scheres SHW. Automated model building and protein identification in cryo-EM maps. Nature 2024; 628:450-457. [PMID: 38408488 PMCID: PMC11006616 DOI: 10.1038/s41586-024-07215-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 02/19/2024] [Indexed: 02/28/2024]
Abstract
Interpreting electron cryo-microscopy (cryo-EM) maps with atomic models requires high levels of expertise and labour-intensive manual intervention in three-dimensional computer graphics programs1,2. Here we present ModelAngelo, a machine-learning approach for automated atomic model building in cryo-EM maps. By combining information from the cryo-EM map with information from protein sequence and structure in a single graph neural network, ModelAngelo builds atomic models for proteins that are of similar quality to those generated by human experts. For nucleotides, ModelAngelo builds backbones with similar accuracy to those built by humans. By using its predicted amino acid probabilities for each residue in hidden Markov model sequence searches, ModelAngelo outperforms human experts in the identification of proteins with unknown sequences. ModelAngelo will therefore remove bottlenecks and increase objectivity in cryo-EM structure determination.
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Affiliation(s)
| | - Lukas Käll
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Rui Zhang
- Washington University in St Louis, St Louis, MO, USA
| | - Alan Brown
- Blavatnik Institute, Harvard Medical School, Boston, MA, USA
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7
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Brody SL, Pan J, Huang T, Xu J, Xu H, Koenitizer J, Brennan SK, Nanjundappa R, Saba TG, Berical A, Hawkins FJ, Wang X, Zhang R, Mahjoub MR, Horani A, Dutcher SK. Loss of an extensive ciliary connectome induces proteostasis and cell fate switching in a severe motile ciliopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.20.585965. [PMID: 38562900 PMCID: PMC10983967 DOI: 10.1101/2024.03.20.585965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Motile cilia have essential cellular functions in development, reproduction, and homeostasis. Genetic causes for motile ciliopathies have been identified, but the consequences on cellular functions beyond impaired motility remain unknown. Variants in CCDC39 and CCDC40 cause severe disease not explained by loss of motility. Using human cells with pathological variants in these genes, Chlamydomonas genetics, cryo-electron microscopy, single cell RNA transcriptomics, and proteomics, we identified perturbations in multiple cilia-independent pathways. Absence of the axonemal CCDC39/CCDC40 heterodimer results in loss of a connectome of over 90 proteins. The undocked connectome activates cell quality control pathways, switches multiciliated cell fate, impairs microtubule architecture, and creates a defective periciliary barrier. Both cilia-dependent and independent defects are likely responsible for the disease severity. Our findings provide a foundation for reconsidering the broad cellular impact of pathologic variants in ciliopathies and suggest new directions for therapies.
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Affiliation(s)
- Steven L Brody
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jiehong Pan
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Tao Huang
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jian Xu
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Huihui Xu
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Jeffrey Koenitizer
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Steven K Brennan
- Department of Pediatrics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Rashmi Nanjundappa
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Thomas G Saba
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, 48108, USA
| | - Andrew Berical
- Center for Regenerative Medicine, Boston University, Boston, MA, 02118, USA
| | - Finn J Hawkins
- Center for Regenerative Medicine, Boston University, Boston, MA, 02118, USA
| | - Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Moe R Mahjoub
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, 63110, USA
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Amjad Horani
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, 48108, USA
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Susan K Dutcher
- Department of Cell Biology and Physisology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110, USA
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8
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Garg A, Jansen S, Zhang R, Lavine KJ, Greenberg MJ. Dilated cardiomyopathy-associated skeletal muscle actin (ACTA1) mutation R256H disrupts actin structure and function and causes cardiomyocyte hypocontractility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.10.583979. [PMID: 38559046 PMCID: PMC10979883 DOI: 10.1101/2024.03.10.583979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Skeletal muscle actin (ACTA1) mutations are a prevalent cause of skeletal myopathies consistent with ACTA1's high expression in skeletal muscle. Rare de novo mutations in ACTA1 associated with combined cardiac and skeletal myopathies have been reported, but ACTA1 represents only ~20% of the total actin pool in cardiomyocytes, making its role in cardiomyopathy controversial. Here we demonstrate how a mutation in an actin isoform expressed at low levels in cardiomyocytes can cause cardiomyopathy by focusing on a unique ACTA1 mutation, R256H. We previously identified this mutation in multiple family members with dilated cardiomyopathy (DCM), who had reduced systolic function without clinical skeletal myopathy. Using a battery of multiscale biophysical tools, we show that R256H has potent functional effects on ACTA1 function at the molecular scale and in human cardiomyocytes. Importantly, we demonstrate that R256H acts in a dominant manner, where the incorporation of small amounts of mutant protein into thin filaments is sufficient to disrupt molecular contractility, and that this effect is dependent on the presence of troponin and tropomyosin. To understand the structural basis of this change in regulation, we resolved a structure of R256H filaments using Cryo-EM, and we see alterations in actin's structure that have the potential to disrupt interactions with tropomyosin. Finally, we show that ACTA1R256H/+ human induced pluripotent stem cell cardiomyocytes demonstrate reduced contractility and sarcomeric disorganization. Taken together, we demonstrate that R256H has multiple effects on ACTA1 function that are sufficient to cause reduced contractility and establish a likely causative relationship between ACTA1 R256H and clinical cardiomyopathy.
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Affiliation(s)
- Ankit Garg
- Division of Cardiology, Department of Medicine Johns Hopkins University Baltimore MD USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Silvia Jansen
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kory J. Lavine
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Michael J. Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
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Penny GM, Dutcher SK. Gene dosage of independent dynein arm motor preassembly factors influences cilia assembly in Chlamydomonas reinhardtii. PLoS Genet 2024; 20:e1011038. [PMID: 38498551 PMCID: PMC11020789 DOI: 10.1371/journal.pgen.1011038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 04/16/2024] [Accepted: 02/26/2024] [Indexed: 03/20/2024] Open
Abstract
Motile cilia assembly utilizes over 800 structural and cytoplasmic proteins. Variants in approximately 58 genes cause primary ciliary dyskinesia (PCD) in humans, including the dynein arm (pre)assembly factor (DNAAF) gene DNAAF4. In humans, outer dynein arms (ODAs) and inner dynein arms (IDAs) fail to assemble motile cilia when DNAAF4 function is disrupted. In Chlamydomonas reinhardtii, a ciliated unicellular alga, the DNAAF4 ortholog is called PF23. The pf23-1 mutant assembles short cilia and lacks IDAs, but partially retains ODAs. The cilia of a new null allele (pf23-4) completely lack ODAs and IDAs and are even shorter than cilia from pf23-1. In addition, PF23 plays a role in the cytoplasmic modification of IC138, a protein of the two-headed IDA (I1/f). As most PCD variants in humans are recessive, we sought to test if heterozygosity at two genes affects ciliary function using a second-site non-complementation (SSNC) screening approach. We asked if phenotypes were observed in diploids with pairwise heterozygous combinations of 21 well-characterized ciliary mutant Chlamydomonas strains. Vegetative cultures of single and double heterozygous diploid cells did not show SSNC for motility phenotypes. When protein synthesis is inhibited, wild-type Chlamydomonas cells utilize the pool of cytoplasmic proteins to assemble half-length cilia. In this sensitized assay, 8 double heterozygous diploids with pf23 and other DNAAF mutations show SSNC; they assemble shorter cilia than wild-type. In contrast, double heterozygosity of the other 203 strains showed no effect on ciliary assembly. Immunoblots of diploids heterozygous for pf23 and wdr92 or oda8 show that PF23 is reduced by half in these strains, and that PF23 dosage affects phenotype severity. Reductions in PF23 and another DNAAF in diploids affect the ability to assemble ODAs and IDAs and impedes ciliary assembly. Thus, dosage of multiple DNAAFs is an important factor in cilia assembly and regeneration.
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Affiliation(s)
- Gervette M. Penny
- Department of Genetics, Washington University in Saint Louis, Saint Louis,Missouri, United States of America
| | - Susan K. Dutcher
- Department of Genetics, Washington University in Saint Louis, Saint Louis,Missouri, United States of America
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10
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Rao L, Gennerich A. Structure and Function of Dynein's Non-Catalytic Subunits. Cells 2024; 13:330. [PMID: 38391943 PMCID: PMC10886578 DOI: 10.3390/cells13040330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/05/2024] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Dynein, an ancient microtubule-based motor protein, performs diverse cellular functions in nearly all eukaryotic cells, with the exception of land plants. It has evolved into three subfamilies-cytoplasmic dynein-1, cytoplasmic dynein-2, and axonemal dyneins-each differentiated by their cellular functions. These megadalton complexes consist of multiple subunits, with the heavy chain being the largest subunit that generates motion and force along microtubules by converting the chemical energy of ATP hydrolysis into mechanical work. Beyond this catalytic core, the functionality of dynein is significantly enhanced by numerous non-catalytic subunits. These subunits are integral to the complex, contributing to its stability, regulating its enzymatic activities, targeting it to specific cellular locations, and mediating its interactions with other cofactors. The diversity of non-catalytic subunits expands dynein's cellular roles, enabling it to perform critical tasks despite the conservation of its heavy chains. In this review, we discuss recent findings and insights regarding these non-catalytic subunits.
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Affiliation(s)
- Lu Rao
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Arne Gennerich
- Department of Biochemistry and Gruss Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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11
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Rao VG, Shendge AA, D'Gama PP, Martis EAF, Mehta S, Coutinho EC, D'Souza JS. A-kinase anchoring proteins are enriched in the central pair microtubules of motile cilia in Chlamydomonas reinhardtii. FEBS Lett 2024; 598:457-476. [PMID: 38140814 DOI: 10.1002/1873-3468.14791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 12/24/2023]
Abstract
Cilia are microtubule-based sensory organelles present in a number of eukaryotic cells. Mutations in the genes encoding ciliary proteins cause ciliopathies in humans. A-kinase anchoring proteins (AKAPs) tether ciliary signaling proteins such as protein kinase A (PKA). The dimerization and docking domain (D/D) on the RIIα subunit of PKA interacts with AKAPs. Here, we show that AKAP240 from the central-pair microtubules of Chlamydomonas reinhardtii cilia uses two C-terminal amphipathic helices to bind to its partner FAP174, an RIIα-like protein with a D/D domain at the N-terminus. Co-immunoprecipitation using anti-FAP174 antibody with an enriched central-pair microtubule fraction isolated seven interactors whose mass spectrometry analysis revealed proteins from the C2a (FAP65, FAP70, and FAP147) and C1b (CPC1, HSP70A, and FAP42) microtubule projections and FAP75, a protein whose sub-ciliary localization is unknown. Using RII D/D and FAP174 as baits, we identified two additional AKAPs (CPC1 and FAP297) in the central-pair microtubules.
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Affiliation(s)
- Venkatramanan G Rao
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai, India
| | - Amruta A Shendge
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai, India
| | - Percival P D'Gama
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai, India
| | - Elvis A F Martis
- Molecular Simulations Group, Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Santacruz (E), Mumbai, India
| | - Shraddha Mehta
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai, India
| | - Evans C Coutinho
- Molecular Simulations Group, Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Santacruz (E), Mumbai, India
- St John Institute of Pharmacy and Research, Palghar (E), Maharashtra, India
| | - Jacinta S D'Souza
- School of Biological Sciences, UM-DAE Centre for Excellence in Basic Sciences, Kalina Campus, Santacruz (E), Mumbai, India
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12
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Shimogawa MM, Jonnalagadda K, Hill KL. FAP20 is required for flagellum assembly in Trypanosoma brucei. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.19.576295. [PMID: 38293126 PMCID: PMC10827224 DOI: 10.1101/2024.01.19.576295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Trypanosoma brucei is a human and animal pathogen that depends on flagellar motility for transmission and infection. The trypanosome flagellum is built around a canonical "9+2" axoneme, containing nine doublet microtubules (DMTs) surrounding two singlet microtubules. Each DMT contains a 13-protofilament A-tubule and a 10-protofilament B-tubule, connected to the A-tubule by a conserved, non-tubulin inner junction (IJ) filament made up of alternating PACRG and FAP20 subunits. Here we investigate FAP20 in procyclic form T. brucei. A FAP20-NeonGreen fusion protein localized to the axoneme as expected. Surprisingly, FAP20 knockdown led to a catastrophic failure in flagellum assembly and concomitant lethal cell division defect. This differs from other organisms, where FAP20 is required for normal flagellum motility, but generally dispensable for flagellum assembly and viability. Transmission electron microscopy demonstrates failed flagellum assembly in FAP20 mutants is associated with a range of DMT defects and defective assembly of the paraflagellar rod, a lineage-specific flagellum filament that attaches to DMT 4-7 in trypanosomes. Our studies reveal a lineage-specific requirement for FAP20 in trypanosomes, offering insight into adaptations for flagellum stability and motility in these parasites and highlighting pathogen versus host differences that might be considered for therapeutic intervention in trypanosome diseases.
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Affiliation(s)
- Michelle M. Shimogawa
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Keya Jonnalagadda
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Kent L. Hill
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, CA, 90095, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 90095, USA
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13
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Bangera M, Dungdung A, Prabhu S, Sirajuddin M. Doublet microtubule inner junction protein FAP20 recruits tubulin to the microtubule lattice. Structure 2023; 31:1535-1544.e4. [PMID: 37816351 PMCID: PMC7615566 DOI: 10.1016/j.str.2023.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/12/2023] [Accepted: 09/13/2023] [Indexed: 10/12/2023]
Abstract
Doublet microtubules of eukaryotic cilia and flagella are made up of a complete A- and an incomplete B-tubule that are fused together. Of the two fusion points, the outer junction is made of tripartite tubulin connections, while the inner junction contains non-tubulin elements. The latter includes flagellar-associated protein 20 (FAP20) and Parkin co-regulated gene protein (PACRG) that together link the A- and B-tubule at the inner junction. While structures of doublet microtubules reveal molecular details, their assembly is poorly understood. In this study, we purified recombinant FAP20 and characterized its effects on microtubule dynamics. We use in vitro reconstitution and cryo-electron microscopy to show that FAP20 recruits free tubulin to the existing microtubule lattice. Our cryo-electron microscopy reconstruction of microtubule:FAP20:tubulin complex reveals the mode of tubulin recruitment by FAP20 onto microtubules, providing insights into assembly steps of B-tubule closure during doublet microtubule formation.
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Affiliation(s)
- Mamata Bangera
- Institute for Stem Cell Science and Regenerative Medicine, GKVK Campus, Bengaluru 560065, India
| | - Archita Dungdung
- Institute for Stem Cell Science and Regenerative Medicine, GKVK Campus, Bengaluru 560065, India
| | - Sujana Prabhu
- Institute for Stem Cell Science and Regenerative Medicine, GKVK Campus, Bengaluru 560065, India
| | - Minhajuddin Sirajuddin
- Institute for Stem Cell Science and Regenerative Medicine, GKVK Campus, Bengaluru 560065, India.
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14
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Black CS, Bui KH. Unveiling the intriguing role of FAP20 in tubulin recruitment at the doublet microtubule inner junctions. Structure 2023; 31:1518-1519. [PMID: 38065073 DOI: 10.1016/j.str.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/10/2023] [Accepted: 11/10/2023] [Indexed: 12/18/2023]
Abstract
In this issue of Structure, Bangera et al. investigate the role of the inner junction protein FAP20 in doublet microtubule assembly. Using cryo-EM and microtubule dynamic assays, they demonstrate that FAP20 recruits free tubulins to existing microtubule lattices, shedding light on B-tubule closure during doublet microtubule formation.
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Affiliation(s)
- Corbin S Black
- Facility for Electron Microscopy Research, McGill University, Montreal, QC, Canada.
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada.
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15
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Wang Y, Yang J, Hu F, Yang Y, Huang K, Zhang K. Cryo-EM reveals how the mastigoneme assembles and responds to environmental signal changes. J Cell Biol 2023; 222:e202301066. [PMID: 37882754 PMCID: PMC10602792 DOI: 10.1083/jcb.202301066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 08/24/2023] [Accepted: 09/19/2023] [Indexed: 10/27/2023] Open
Abstract
Mastigonemes are thread-like structures adorning the flagella of protists. In Chlamydomonas reinhardtii, filamentous mastigonemes find their roots in the flagella's distal region, associated with the channel protein PKD2, implying their potential contribution to external signal sensing and flagellar motility control. Here, we present the single-particle cryo-electron microscopy structure of the mastigoneme at 3.4 Å. The filament unit, MST1, consists of nine immunoglobulin-like domains and six Sushi domains, trailed by an elastic polyproline-II helix. Our structure demonstrates that MST1 subunits are periodically assembled to form a centrosymmetric, non-polar filament. Intriguingly, numerous clustered disulfide bonds within a ladder-like spiral configuration underscore structural resilience. While defects in the mastigoneme structure did not noticeably affect general attributes of cell swimming, they did impact specific swimming properties, particularly under varied environmental conditions such as redox shifts and heightened viscosity. Our findings illuminate the potential role of mastigonemes in flagellar motility and suggest their involvement in diverse environmental responses.
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Affiliation(s)
- Yue Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jun Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Fangheng Hu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Yuchen Yang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Kaiyao Huang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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16
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Zhao X, Ge H, Xu W, Cheng C, Zhou W, Xu Y, Fan J, Liu Y, Tian X, Xu KF, Zhang X. Lack of CFAP54 causes primary ciliary dyskinesia in a mouse model and human patients. Front Med 2023; 17:1236-1249. [PMID: 37725231 DOI: 10.1007/s11684-023-0997-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 03/06/2023] [Indexed: 09/21/2023]
Abstract
Primary ciliary dyskinesia (PCD) is a highly heterogeneous recessive inherited disorder. FAP54, the homolog of CFAP54 in Chlamydomonas reinhardtii, was previously demonstrated as the C1d projection of the central microtubule apparatus of flagella. A Cfap54 knockout mouse model was then reported to have PCD-relevant phenotypes. Through whole-exome sequencing, compound heterozygous variants c.2649_2657delinC (p. E883Dfs*47) and c.7312_7313insCGCAGGCTGAATTCTTGG (p. T2438delinsTQAEFLA) in a new suspected PCD-relevant gene, CFAP54, were identified in an individual with PCD. Two missense variants, c.4112A>C (p. E1371A) and c.6559C>T (p. P2187S), in CFAP54 were detected in another unrelated patient. In this study, a minigene assay was conducted on the frameshift mutation showing a reduction in mRNA expression. In addition, a CFAP54 in-frame variant knock-in mouse model was established, which recapitulated the typical symptoms of PCD, including hydrocephalus, infertility, and mucus accumulation in nasal sinuses. Correspondingly, two missense variants were deleterious, with a dramatic reduction in mRNA abundance from bronchial tissue and sperm. The identification of PCD-causing variants of CFAP54 in two unrelated patients with PCD for the first time provides strong supportive evidence that CFAP54 is a new PCD-causing gene. This study further helps expand the disease-associated gene spectrum and improve genetic testing for PCD diagnosis in the future.
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Affiliation(s)
- Xinyue Zhao
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China
| | - Haijun Ge
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China
| | - Wenshuai Xu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China
| | - Chongsheng Cheng
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Wangji Zhou
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Yan Xu
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Junping Fan
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Yaping Liu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China.
| | - Xinlun Tian
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China.
| | - Kai-Feng Xu
- Department of Pulmonary and Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100730, China
| | - Xue Zhang
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100005, China
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17
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Legal T, Parra M, Tong M, Black CS, Joachimiak E, Valente-Paterno M, Lechtreck K, Gaertig J, Bui KH. CEP104/FAP256 and associated cap complex maintain stability of the ciliary tip. J Cell Biol 2023; 222:e202301129. [PMID: 37756660 PMCID: PMC10522465 DOI: 10.1083/jcb.202301129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/13/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show that the microtubules at the tip are highly crosslinked with each other and stabilized by luminal proteins, plugs, and cap proteins at the plus ends. In the tip region, the central pair lacks typical projections and twists significantly. By analyzing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explained the potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and the mechanisms of ciliary assembly and length regulation.
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Affiliation(s)
- Thibault Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Mireya Parra
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Maxwell Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Corbin S. Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, Warsaw, Poland
| | - Melissa Valente-Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - Karl Lechtreck
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
| | - Khanh Huy Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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18
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Jamali K, Käll L, Zhang R, Brown A, Kimanius D, Scheres SH. Automated model building and protein identification in cryo-EM maps. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.541002. [PMID: 37292681 PMCID: PMC10245678 DOI: 10.1101/2023.05.16.541002] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Interpreting electron cryo-microscopy (cryo-EM) maps with atomic models requires high levels of expertise and labour-intensive manual intervention. We present ModelAngelo, a machine-learning approach for automated atomic model building in cryo-EM maps. By combining information from the cryo-EM map with information from protein sequence and structure in a single graph neural network, ModelAngelo builds atomic models for proteins that are of similar quality as those generated by human experts. For nucleotides, ModelAngelo builds backbones with similar accuracy as humans. By using its predicted amino acid probabilities for each residue in hidden Markov model sequence searches, ModelAngelo outperforms human experts in the identification of proteins with unknown sequences. ModelAngelo will thus remove bottlenecks and increase objectivity in cryo-EM structure determination.
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Affiliation(s)
| | - Lukas Käll
- Science for Life Laboratory, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Rui Zhang
- Washington University in St. Louis, St. Louis, MO, USA
| | - Alan Brown
- Blavatnik Institute, Harvard Medical School, Boston, MA, USA
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19
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Salve BG, Kurian AM, Vijay N. Concurrent loss of ciliary genes WDR93 and CFAP46 in phylogenetically distant birds. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230801. [PMID: 37621660 PMCID: PMC10445033 DOI: 10.1098/rsos.230801] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/01/2023] [Indexed: 08/26/2023]
Abstract
The respiratory system is the primary route of infection for many contagious pathogens. Mucociliary clearance of inhaled pathogens is an important innate defence mechanism sustained by the rhythmic movement of epithelial cilia. To counter host defences, viral pathogens target epithelial cells and cilia. For instance, the avian influenza virus that targets ciliated cells modulates the expression of WDR93, a central ciliary apparatus C1d projection component. Lineage-specific prevalence of such host defence genes results in differential susceptibility. In this study, the comparative analysis of approximately 500 vertebrate genomes from seven taxonomic classes spanning 73 orders confirms the widespread conservation of WDR93 across these different vertebrate groups. However, we established loss of the WDR93 in landfowl, geese and other phylogenetically independent bird species due to gene-disrupting changes. The lack of WDR93 transcripts in species with gene loss in contrast to its expression in species with an intact gene confirms gene loss. Notably, species with WDR93 loss have concurrently lost another C1d component, CFAP46, through large segmental deletions. Understanding the consequences of such gene loss may provide insight into their role in host-pathogen interactions and benefit global pathogen surveillance efforts by prioritizing species missing host defence genes and identifying putative zoonotic reservoirs.
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Affiliation(s)
- Buddhabhushan Girish Salve
- Computational Evolutionary Genomics Lab, Department of Biological Sciences, IISER Bhopal, Bhauri, Madhya Pradesh, India
| | - Amia Miriam Kurian
- Computational Evolutionary Genomics Lab, Department of Biological Sciences, IISER Bhopal, Bhauri, Madhya Pradesh, India
| | - Nagarjun Vijay
- Computational Evolutionary Genomics Lab, Department of Biological Sciences, IISER Bhopal, Bhauri, Madhya Pradesh, India
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20
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Leung MR, Zeng J, Wang X, Roelofs MC, Huang W, Zenezini Chiozzi R, Hevler JF, Heck AJR, Dutcher SK, Brown A, Zhang R, Zeev-Ben-Mordehai T. Structural specializations of the sperm tail. Cell 2023; 186:2880-2896.e17. [PMID: 37327785 PMCID: PMC10948200 DOI: 10.1016/j.cell.2023.05.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 03/16/2023] [Accepted: 05/17/2023] [Indexed: 06/18/2023]
Abstract
Sperm motility is crucial to reproductive success in sexually reproducing organisms. Impaired sperm movement causes male infertility, which is increasing globally. Sperm are powered by a microtubule-based molecular machine-the axoneme-but it is unclear how axonemal microtubules are ornamented to support motility in diverse fertilization environments. Here, we present high-resolution structures of native axonemal doublet microtubules (DMTs) from sea urchin and bovine sperm, representing external and internal fertilizers. We identify >60 proteins decorating sperm DMTs; at least 15 are sperm associated and 16 are linked to infertility. By comparing DMTs across species and cell types, we define core microtubule inner proteins (MIPs) and analyze evolution of the tektin bundle. We identify conserved axonemal microtubule-associated proteins (MAPs) with unique tubulin-binding modes. Additionally, we identify a testis-specific serine/threonine kinase that links DMTs to outer dense fibers in mammalian sperm. Our study provides structural foundations for understanding sperm evolution, motility, and dysfunction at a molecular level.
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Affiliation(s)
- Miguel Ricardo Leung
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Jianwei Zeng
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Marc C Roelofs
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, USA
| | - Riccardo Zenezini Chiozzi
- Biomolecular Mass Spectrometry & Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Johannes F Hevler
- Biomolecular Mass Spectrometry & Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry & Proteomics, Bijvoet Centre for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Susan K Dutcher
- Department of Genetics, Washington University in St. Louis, St Louis, MO, USA
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
| | - Tzviya Zeev-Ben-Mordehai
- Structural Biochemistry, Bijvoet Centre for Biomolecular Research, Utrecht University, 3584 CG Utrecht, the Netherlands.
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21
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Zhou L, Liu H, Liu S, Yang X, Dong Y, Pan Y, Xiao Z, Zheng B, Sun Y, Huang P, Zhang X, Hu J, Sun R, Feng S, Zhu Y, Liu M, Gui M, Wu J. Structures of sperm flagellar doublet microtubules expand the genetic spectrum of male infertility. Cell 2023; 186:2897-2910.e19. [PMID: 37295417 DOI: 10.1016/j.cell.2023.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 04/08/2023] [Accepted: 05/10/2023] [Indexed: 06/12/2023]
Abstract
Sperm motility is crucial for successful fertilization. Highly decorated doublet microtubules (DMTs) form the sperm tail skeleton, which propels the movement of spermatozoa. Using cryo-electron microscopy (cryo-EM) and artificial intelligence (AI)-based modeling, we determined the structures of mouse and human sperm DMTs and built an atomic model of the 48-nm repeat of the mouse sperm DMT. Our analysis revealed 47 DMT-associated proteins, including 45 microtubule inner proteins (MIPs). We identified 10 sperm-specific MIPs, including seven classes of Tektin5 in the lumen of the A tubule and FAM166 family members that bind the intra-tubulin interfaces. Interestingly, the human sperm DMT lacks some MIPs compared with the mouse sperm DMT. We also discovered variants in 10 distinct MIPs associated with a subtype of asthenozoospermia characterized by impaired sperm motility without evident morphological abnormalities. Our study highlights the conservation and tissue/species specificity of DMTs and expands the genetic spectrum of male infertility.
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Affiliation(s)
- Lunni Zhou
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Haobin Liu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Siyu Liu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Xiaoyu Yang
- State Key Laboratory of Reproductive Medicine and Offspring Health, The Center for Clinical Reproductive Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Yue Dong
- State Key Laboratory of Reproductive Medicine and Offspring Health, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Yun Pan
- State Key Laboratory of Reproductive Medicine and Offspring Health, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Zhuang Xiao
- State Key Laboratory of Reproductive Medicine and Offspring Health, Department of Histology and Embryology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China
| | - Beihong Zheng
- Center of Reproductive Medicine, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, China
| | - Yan Sun
- Center of Reproductive Medicine, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, China
| | - Pengyu Huang
- Center of Reproductive Medicine, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou 350001, China
| | - Xixi Zhang
- Liangzhu Laboratory, Zhejiang University, Hangzhou 311121, Zhejiang, China
| | - Jin Hu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Rui Sun
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Shan Feng
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Yi Zhu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China
| | - Mingxi Liu
- State Key Laboratory of Reproductive Medicine and Offspring Health, The Affiliated Taizhou People's Hospital of Nanjing Medical University, Taizhou School of Clinical Medicine, Nanjing Medical University, Nanjing 211166, China.
| | - Miao Gui
- Liangzhu Laboratory, Zhejiang University, Hangzhou 311121, Zhejiang, China; Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Zhejiang Provincial Clinical Research Center for Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310016, Zhejiang, China.
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou 310024, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, Zhejiang, China; Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, Zhejiang, China.
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22
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Erickson T, Biggers WP, Williams K, Butland SE, Venuto A. Regionalized Protein Localization Domains in the Zebrafish Hair Cell Kinocilium. J Dev Biol 2023; 11:28. [PMID: 37367482 DOI: 10.3390/jdb11020028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 05/05/2023] [Accepted: 06/02/2023] [Indexed: 06/28/2023] Open
Abstract
Sensory hair cells are the receptors for auditory, vestibular, and lateral line sensory organs in vertebrates. These cells are distinguished by "hair"-like projections from their apical surface collectively known as the hair bundle. Along with the staircase arrangement of the actin-filled stereocilia, the hair bundle features a single, non-motile, true cilium called the kinocilium. The kinocilium plays an important role in bundle development and the mechanics of sensory detection. To understand more about kinocilial development and structure, we performed a transcriptomic analysis of zebrafish hair cells to identify cilia-associated genes that have yet to be characterized in hair cells. In this study, we focused on three such genes-ankef1a, odf3l2a, and saxo2-because human or mouse orthologs are either associated with sensorineural hearing loss or are located near uncharacterized deafness loci. We made transgenic fish that express fluorescently tagged versions of their proteins, demonstrating their localization to the kinocilia of zebrafish hair cells. Furthermore, we found that Ankef1a, Odf3l2a, and Saxo2 exhibit distinct localization patterns along the length of the kinocilium and within the cell body. Lastly, we have reported a novel overexpression phenotype of Saxo2. Overall, these results suggest that the hair cell kinocilium in zebrafish is regionalized along its proximal-distal axis and set the groundwork to understand more about the roles of these kinocilial proteins in hair cells.
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Affiliation(s)
- Timothy Erickson
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | | | - Kevin Williams
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
| | - Shyanne E Butland
- Department of Biology, University of New Brunswick, Fredericton, NB E3B 5A3, Canada
| | - Alexandra Venuto
- Department of Biology, East Carolina University, Greenville, NC 27858, USA
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23
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Walton T, Gui M, Velkova S, Fassad MR, Hirst RA, Haarman E, O'Callaghan C, Bottier M, Burgoyne T, Mitchison HM, Brown A. Axonemal structures reveal mechanoregulatory and disease mechanisms. Nature 2023; 618:625-633. [PMID: 37258679 PMCID: PMC10266980 DOI: 10.1038/s41586-023-06140-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 04/27/2023] [Indexed: 06/02/2023]
Abstract
Motile cilia and flagella beat rhythmically on the surface of cells to power the flow of fluid and to enable spermatozoa and unicellular eukaryotes to swim. In humans, defective ciliary motility can lead to male infertility and a congenital disorder called primary ciliary dyskinesia (PCD), in which impaired clearance of mucus by the cilia causes chronic respiratory infections1. Ciliary movement is generated by the axoneme, a molecular machine consisting of microtubules, ATP-powered dynein motors and regulatory complexes2. The size and complexity of the axoneme has so far prevented the development of an atomic model, hindering efforts to understand how it functions. Here we capitalize on recent developments in artificial intelligence-enabled structure prediction and cryo-electron microscopy (cryo-EM) to determine the structure of the 96-nm modular repeats of axonemes from the flagella of the alga Chlamydomonas reinhardtii and human respiratory cilia. Our atomic models provide insights into the conservation and specialization of axonemes, the interconnectivity between dyneins and their regulators, and the mechanisms that maintain axonemal periodicity. Correlated conformational changes in mechanoregulatory complexes with their associated axonemal dynein motors provide a mechanism for the long-hypothesized mechanotransduction pathway to regulate ciliary motility. Structures of respiratory-cilia doublet microtubules from four individuals with PCD reveal how the loss of individual docking factors can selectively eradicate periodically repeating structures.
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Affiliation(s)
- Travis Walton
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Miao Gui
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
- Liangzhu Laboratory, Zhejiang University, Hangzhou, China
| | - Simona Velkova
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Mahmoud R Fassad
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Robert A Hirst
- Centre for PCD Diagnosis and Research, Department of Respiratory Sciences, University of Leicester, Leicester, UK
| | - Eric Haarman
- Department of Pediatric Respiratory Medicine and Allergy, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Christopher O'Callaghan
- Infection, Immunity & Inflammation Department, NIHR GOSH BRC, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Mathieu Bottier
- Royal Brompton Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Thomas Burgoyne
- Royal Brompton Hospital, Guy's and St Thomas' NHS Foundation Trust, London, UK
- Institute of Ophthalmology, University College London, London, UK
| | - Hannah M Mitchison
- Genetics and Genomic Medicine Department, UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Alan Brown
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
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24
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Payne ZL, Penny GM, Turner TN, Dutcher SK. A gap-free genome assembly of Chlamydomonas reinhardtii and detection of translocations induced by CRISPR-mediated mutagenesis. PLANT COMMUNICATIONS 2023; 4:100493. [PMID: 36397679 PMCID: PMC10030371 DOI: 10.1016/j.xplc.2022.100493] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/26/2022] [Accepted: 11/15/2022] [Indexed: 05/04/2023]
Abstract
Genomic assemblies of the unicellular green alga Chlamydomonas reinhardtii have provided important resources for researchers. However, assembly errors, large gaps, and unplaced scaffolds as well as strain-specific variants currently impede many types of analysis. By combining PacBio HiFi and Oxford Nanopore long-read technologies, we generated a de novo genome assembly for strain CC-5816, derived from crosses of strains CC-125 and CC-124. Multiple methods of evaluating genome completeness and base-pair error rate suggest that the final telomere-to-telomere assembly is highly accurate. The CC-5816 assembly enabled previously difficult analyses that include characterization of the 17 centromeres, rDNA arrays on three chromosomes, and 56 insertions of organellar DNA into the nuclear genome. Using Nanopore sequencing, we identified sites of cytosine (CpG) methylation, which are enriched at centromeres. We analyzed CRISPR-Cas9 insertional mutants in the PF23 gene. Two of the three alleles produced progeny that displayed patterns of meiotic inviability that suggested the presence of a chromosomal aberration. Mapping Nanopore reads from pf23-2 and pf23-3 onto the CC-5816 genome showed that these two strains each carry a translocation that was initiated at the PF23 gene locus on chromosome 11 and joined with chromosomes 5 or 3, respectively. The translocations were verified by demonstrating linkage between loci on the two translocated chromosomes in meiotic progeny. The three pf23 alleles display the expected short-cilia phenotype, and immunoblotting showed that pf23-2 lacks the PF23 protein. Our CC-5816 genome assembly will undoubtedly provide an important tool for the Chlamydomonas research community.
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Affiliation(s)
- Zachary L Payne
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Gervette M Penny
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Tychele N Turner
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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25
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Chen Z, Greenan GA, Shiozaki M, Liu Y, Skinner WM, Zhao X, Zhao S, Yan R, Yu Z, Lishko PV, Agard DA, Vale RD. In situ cryo-electron tomography reveals the asymmetric architecture of mammalian sperm axonemes. Nat Struct Mol Biol 2023; 30:360-369. [PMID: 36593309 PMCID: PMC10023559 DOI: 10.1038/s41594-022-00861-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 10/11/2022] [Indexed: 01/04/2023]
Abstract
The flagella of mammalian sperm display non-planar, asymmetric beating, in contrast to the planar, symmetric beating of flagella from sea urchin sperm and unicellular organisms. The molecular basis of this difference is unclear. Here, we perform in situ cryo-electron tomography of mouse and human sperm, providing the highest-resolution structural information to date. Our subtomogram averages reveal mammalian sperm-specific protein complexes within the microtubules, the radial spokes and nexin-dynein regulatory complexes. The locations and structures of these complexes suggest potential roles in enhancing the mechanical strength of mammalian sperm axonemes and regulating dynein-based axonemal bending. Intriguingly, we find that each of the nine outer microtubule doublets is decorated with a distinct combination of sperm-specific complexes. We propose that this asymmetric distribution of proteins differentially regulates the sliding of each microtubule doublet and may underlie the asymmetric beating of mammalian sperm.
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Affiliation(s)
- Zhen Chen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Garrett A Greenan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Momoko Shiozaki
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yanxin Liu
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Will M Skinner
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Xiaowei Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Shumei Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Rui Yan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Zhiheng Yu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Polina V Lishko
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Center for Reproductive Longevity and Equality, Buck Institute for Research on Aging, Novato, CA, USA
| | - David A Agard
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, USA.
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
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26
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Towards an atomic model of a beating ciliary axoneme. Curr Opin Struct Biol 2023; 78:102516. [PMID: 36586349 DOI: 10.1016/j.sbi.2022.102516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/15/2022] [Accepted: 11/23/2022] [Indexed: 12/30/2022]
Abstract
The axoneme of motile cilia and eukaryotic flagella is an ordered assembly of hundreds of proteins that powers the locomotion of single cells and generates flow of liquid and particles across certain mammalian tissues. The symmetric and organized structure of the axoneme has invited structural biologists to unravel its intricate architecture at different scales. In the last few years, single-particle cryo-electron microscopy provided high-resolution structures of axonemal complexes that comprise dozens of proteins and are key to cilia function. This review summarizes unique structural features of the axoneme and the framework they provide to understand cilia assembly, the mechanism of ciliary beating, and clinical conditions associated with impaired cilia motility.
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27
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Legal T, Tong M, Black C, Valente Paterno M, Gaertig J, Bui KH. Molecular architecture of the ciliary tip revealed by cryo-electron tomography. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.03.522627. [PMID: 36711791 PMCID: PMC9881849 DOI: 10.1101/2023.01.03.522627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show the microtubules in the tip are highly cross-linked with each other and stabilised by luminal proteins, plugs and cap proteins at the plus ends. In the tip region, the central pair lacks the typical projections and twists significantly. By analysing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explain potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and inform about the mechanisms of ciliary assembly and length regulation.
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Affiliation(s)
- T Legal
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - M Tong
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - C Black
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - M Valente Paterno
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
| | - J Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, United States of America
| | - K H Bui
- Department of Anatomy and Cell Biology, Faculty of Medicine and Health Sciences, McGill University, Québec, Canada
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28
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Abstract
Cilia are cell-surface organelles with cytoskeletons formed by different microtubule types. These microtubules are decorated inside and out by proteins that alter microtubule stability and elasticity and allow cilia to beat. Mutations in these proteins are associated with human ciliopathies such as primary ciliary dyskinesia. Here, we used cryo-EM to reveal the structures of two distinct types of human ciliary microtubule: the doublet microtubules of respiratory tract cilia and the distal singlet microtubules of the sperm tail. Among the microtubule-binding proteins identified is SPACA9, which we show is capable of forming both spirals and striations within human ciliary microtubules. The ability to resolve human ciliary microtubule composition improves our understanding of ciliary complexes and the potential causes of human ciliopathies. The cilium-centrosome complex contains triplet, doublet, and singlet microtubules. The lumenal surfaces of each microtubule within this diverse array are decorated by microtubule inner proteins (MIPs). Here, we used single-particle cryo-electron microscopy methods to build atomic models of two types of human ciliary microtubule: the doublet microtubules of multiciliated respiratory cells and the distal singlet microtubules of monoflagellated human spermatozoa. We discover that SPACA9 is a polyspecific MIP capable of binding both microtubule types. SPACA9 forms intralumenal striations in the B tubule of respiratory doublet microtubules and noncontinuous spirals in sperm singlet microtubules. By acquiring new and reanalyzing previous cryo-electron tomography data, we show that SPACA9-like intralumenal striations are common features of different microtubule types in animal cilia. Our structures provide detailed references to help rationalize ciliopathy-causing mutations and position cryo-EM as a tool for the analysis of samples obtained directly from ciliopathy patients.
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29
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Mechanisms of Regulation in Intraflagellar Transport. Cells 2022; 11:cells11172737. [PMID: 36078145 PMCID: PMC9454703 DOI: 10.3390/cells11172737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 08/30/2022] [Accepted: 08/31/2022] [Indexed: 11/30/2022] Open
Abstract
Cilia are eukaryotic organelles essential for movement, signaling or sensing. Primary cilia act as antennae to sense a cell’s environment and are involved in a wide range of signaling pathways essential for development. Motile cilia drive cell locomotion or liquid flow around the cell. Proper functioning of both types of cilia requires a highly orchestrated bi-directional transport system, intraflagellar transport (IFT), which is driven by motor proteins, kinesin-2 and IFT dynein. In this review, we explore how IFT is regulated in cilia, focusing from three different perspectives on the issue. First, we reflect on how the motor track, the microtubule-based axoneme, affects IFT. Second, we focus on the motor proteins, considering the role motor action, cooperation and motor-train interaction plays in the regulation of IFT. Third, we discuss the role of kinases in the regulation of the motor proteins. Our goal is to provide mechanistic insights in IFT regulation in cilia and to suggest directions of future research.
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30
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Abstract
Flagellar-driven motility grants unicellular organisms the ability to gather more food and avoid predators, but the energetic costs of construction and operation of flagella are considerable. Paths of flagellar evolution depend on the deviations between fitness gains and energy costs. Using structural data available for all three major flagellar types (bacterial, archaeal, and eukaryotic), flagellar construction costs were determined for Escherichia coli, Pyrococcus furiosus, and Chlamydomonas reinhardtii. Estimates of cell volumes, flagella numbers, and flagellum lengths from the literature yield flagellar costs for another ~200 species. The benefits of flagellar investment were analysed in terms of swimming speed, nutrient collection, and growth rate; showing, among other things, that the cost-effectiveness of bacterial and eukaryotic flagella follows a common trend. However, a comparison of whole-cell costs and flagellum costs across the Tree of Life reveals that only cells with larger cell volumes than the typical bacterium could evolve the more expensive eukaryotic flagellum. These findings provide insight into the unsolved evolutionary question of why the three domains of life each carry their own type of flagellum.
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Affiliation(s)
- Paul E Schavemaker
- Biodesign Center for Mechanisms of Evolution, Arizona State UniversityTempeUnited States
| | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State UniversityTempeUnited States
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31
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Zehr EA, Roll-Mecak A. A look under the hood of the machine that makes cilia beat. Nat Struct Mol Biol 2022; 29:416-418. [PMID: 35578025 DOI: 10.1038/s41594-022-00778-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Elena A Zehr
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA.
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA. .,Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD, USA.
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