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Andreu-Carbó M, Egoldt C, Aumeier C. Microtubule shaft integrity emerges as a crucial determinant of the acetylation pattern. Cytoskeleton (Hoboken) 2024. [PMID: 38923402 DOI: 10.1002/cm.21887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024]
Affiliation(s)
- Mireia Andreu-Carbó
- School of Pharmaceutical Sciences, University of Geneva, Geneva, Switzerland
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Cornelia Egoldt
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Charlotte Aumeier
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
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2
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Cada AK, Mizuno N. Molecular cartography within axons. Curr Opin Cell Biol 2024; 88:102358. [PMID: 38608424 DOI: 10.1016/j.ceb.2024.102358] [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: 11/28/2023] [Revised: 03/22/2024] [Accepted: 03/24/2024] [Indexed: 04/14/2024]
Abstract
Recent advances in imaging methods begin to further illuminate the inner workings of neurons. Views of the axonal landscape through the lens of in situ cryo-electron tomography (cryo-ET) provide a high-resolution atlas of the macromolecular organization in near-native conditions, leading to our growing understanding of the vital roles of compositional and structural organization in maintaining neuronal homeostasis. In this review, we discuss the latest observations concerning the fundamental components found within neuronal compartments, with special emphasis on the axon, branch points, and growth cone. We describe the similarity and difference in organization of organelles and molecules in varying compartments. Finally, we highlight outstanding questions on the dynamics and localization of various components along the axon that may be answered using orthogonal approaches.
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Affiliation(s)
- A King Cada
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA
| | - Naoko Mizuno
- Laboratory of Structural Cell Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA; National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, 50 South Drive, Bethesda, MD, 20892, USA.
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3
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Seo D, Brito Oliveira S, Rex EA, Ye X, Rice LM, da Fonseca FG, Gammon DB. Poxvirus A51R proteins regulate microtubule stability and antagonize a cell-intrinsic antiviral response. Cell Rep 2024; 43:113882. [PMID: 38457341 PMCID: PMC11023057 DOI: 10.1016/j.celrep.2024.113882] [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: 07/26/2023] [Revised: 01/28/2024] [Accepted: 02/13/2024] [Indexed: 03/10/2024] Open
Abstract
Numerous viruses alter host microtubule (MT) networks during infection, but how and why they induce these changes is unclear in many cases. We show that the vaccinia virus (VV)-encoded A51R protein is a MT-associated protein (MAP) that directly binds MTs and stabilizes them by both promoting their growth and preventing their depolymerization. Furthermore, we demonstrate that A51R-MT interactions are conserved across A51R proteins from multiple poxvirus genera, and highly conserved, positively charged residues in A51R proteins mediate these interactions. Strikingly, we find that viruses encoding MT interaction-deficient A51R proteins fail to suppress a reactive oxygen species (ROS)-dependent antiviral response in macrophages that leads to a block in virion morphogenesis. Moreover, A51R-MT interactions are required for VV virulence in mice. Collectively, our data show that poxviral MAP-MT interactions overcome a cell-intrinsic antiviral ROS response in macrophages that would otherwise block virus morphogenesis and replication in animals.
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Affiliation(s)
- Dahee Seo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sabrynna Brito Oliveira
- Laboratório de Virologia Básica e Aplicada, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Emily A Rex
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xuecheng Ye
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Luke M Rice
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Flávio Guimarães da Fonseca
- Laboratório de Virologia Básica e Aplicada, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil
| | - Don B Gammon
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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4
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Reber S, Singer M, Frischknecht F. Cytoskeletal dynamics in parasites. Curr Opin Cell Biol 2024; 86:102277. [PMID: 38048658 DOI: 10.1016/j.ceb.2023.102277] [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: 07/03/2023] [Revised: 10/12/2023] [Accepted: 10/17/2023] [Indexed: 12/06/2023]
Abstract
Cytoskeletal dynamics are essential for cellular homeostasis and development for both metazoans and protozoans. The function of cytoskeletal elements in protozoans can diverge from that of metazoan cells, with microtubules being more stable and actin filaments being more dynamic. This is particularly striking in protozoan parasites that evolved to enter metazoan cells. Here, we review recent progress towards understanding cytoskeletal dynamics in protozoan parasites, with a focus on divergent properties compared to classic model organisms.
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Affiliation(s)
- Simone Reber
- Max Planck Institute for Infection Biology, 10117 Berlin, Germany; University of Applied Sciences Berlin, 13353 Berlin, Germany
| | - Mirko Singer
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical Faculty, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, DZIF Partner Site Heidelberg, Heidelberg, Germany.
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical Faculty, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; German Center for Infection Research, DZIF Partner Site Heidelberg, Heidelberg, Germany
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5
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Sun X, Ogbolu VC, Baas PW, Qiang L. Reevaluating tau reduction as a therapeutic approach for tauopathies: Insights and perspectives. Cytoskeleton (Hoboken) 2024; 81:57-62. [PMID: 37819557 PMCID: PMC10843461 DOI: 10.1002/cm.21790] [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: 07/25/2023] [Revised: 08/24/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023]
Abstract
Tau, one of the most abundant microtubule-associated protein in neurons plays a role in regulating microtubule dynamics in axons, as well as shaping the overall morphology of the axon. Recent studies challenge the traditional view of tau as a microtubule stabilizer and shed new light on the complexity of its role in regulating various properties of the microtubule. While reducing tau levels shows therapeutic promise for early tauopathies, efficacy wanes in later stages due to resilient toxic tau aggregates and neurofibrillary tangles. Notably, tauopathies involve factors beyond toxic tau alone, necessitating a broader therapeutic approach. Overexpression of human tau in mouse models, although useful for answering some questions, may not accurately reflect disease mechanisms in patients with tauopathies. Furthermore, the interplay between tau and MAP6, another microtubule-associated protein, adds complexity to tau's regulation of microtubule dynamics. Tau promotes the formation and elongation of labile microtubule domains, vital for cellular processes, while MAP6 stabilizes microtubules. A delicate balance between these proteins is important for neuronal function. Therefore, tau reduction therapies require a comprehensive understanding of disease progression, considering functional tau loss, toxic aggregates, and microtubule dynamics. Stage-dependent application and potential unintended consequences must be carefully evaluated. Restoring microtubule dynamics in late-stage tauopathies may necessitate alternative strategies. This knowledge is valuable for developing effective and safe treatments for tauopathies.
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Affiliation(s)
- Xiaohuan Sun
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Victor C. Ogbolu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Peter W. Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
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6
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Romeiro Motta M, Biswas S, Schaedel L. Beyond uniformity: Exploring the heterogeneous and dynamic nature of the microtubule lattice. Eur J Cell Biol 2023; 102:151370. [PMID: 37922811 DOI: 10.1016/j.ejcb.2023.151370] [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: 08/14/2023] [Revised: 10/17/2023] [Accepted: 10/26/2023] [Indexed: 11/07/2023] Open
Abstract
A fair amount of research on microtubules since their discovery in 1963 has focused on their dynamic tips. In contrast, the microtubule lattice was long believed to be highly regular and static, and consequently received far less attention. Yet, as it turned out, the microtubule lattice is neither as regular, nor as static as previously believed: structural studies uncovered the remarkable wealth of different conformations the lattice can accommodate. In the last decade, the microtubule lattice was shown to be labile and to spontaneously undergo renovation, a phenomenon that is intimately linked to structural defects and was called "microtubule self-repair". Following this breakthrough discovery, further recent research provided a deeper understanding of the lattice self-repair mechanism, which we review here. Instrumental to these discoveries were in vitro microtubule reconstitution assays, in which microtubules are grown from the minimal components required for their dynamics. In this review, we propose a shift from the term "lattice self-repair" to "lattice dynamics", since this phenomenon is an inherent property of microtubules and can happen without microtubule damage. We focus on how in vitro microtubule reconstitution assays helped us learn (1) which types of structural variations microtubules display, (2) how these structural variations influence lattice dynamics and microtubule damage caused by mechanical stress, (3) how lattice dynamics impact tip dynamics, and (4) how microtubule-associated proteins (MAPs) can play a role in structuring the lattice. Finally, we discuss the unanswered questions about lattice dynamics and how technical advances will help us tackle these questions.
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Affiliation(s)
- Mariana Romeiro Motta
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany; Laboratoire Reproduction et Développement des Plantes, Université de Lyon, École normale supérieure de Lyon, Lyon 69364, France
| | - Subham Biswas
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany
| | - Laura Schaedel
- Department of Physics, Center for Biophysics, Campus A2 4, Saarland University, 66123 Saarbrücken, Germany.
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7
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Sasaki T, Saito K, Inoue D, Serk H, Sugiyama Y, Pesquet E, Shimamoto Y, Oda Y. Confined-microtubule assembly shapes three-dimensional cell wall structures in xylem vessels. Nat Commun 2023; 14:6987. [PMID: 37957173 PMCID: PMC10643555 DOI: 10.1038/s41467-023-42487-w] [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: 02/17/2023] [Accepted: 10/12/2023] [Indexed: 11/15/2023] Open
Abstract
Properly patterned deposition of cell wall polymers is prerequisite for the morphogenesis of plant cells. A cortical microtubule array guides the two-dimensional pattern of cell wall deposition. Yet, the mechanism underlying the three-dimensional patterning of cell wall deposition is poorly understood. In metaxylem vessels, cell wall arches are formed over numerous pit membranes, forming highly organized three-dimensional cell wall structures. Here, we show that the microtubule-associated proteins, MAP70-5 and MAP70-1, regulate arch development. The map70-1 map70-5 plants formed oblique arches in an abnormal orientation in pits. Microtubules fit the aperture of developing arches in wild-type cells, whereas microtubules in map70-1 map70-5 cells extended over the boundaries of pit arches. MAP70 caused the bending and bundling of microtubules. These results suggest that MAP70 confines microtubules within the pit apertures by altering the physical properties of microtubules, thereby directing the growth of pit arches in the proper orientation. This study provides clues to understanding how plants develop three-dimensional structure of cell walls.
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Affiliation(s)
- Takema Sasaki
- Department of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Kei Saito
- Department of Chromosome Science, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI University, Mishima, Shizuoka, Japan
| | - Daisuke Inoue
- Factuly of Design, Kyusyu University, Fukuoka, Japan
| | - Henrik Serk
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Yuki Sugiyama
- Department of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
- Institute for Advanced Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Edouard Pesquet
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, Umeå, Sweden
- Arrhenius laboratories, Department of Ecology, Environment and Plant Sciences (DEEP), Stockholm University, Stockholm, Sweden
| | - Yuta Shimamoto
- Department of Chromosome Science, National Institute of Genetics, Mishima, Shizuoka, Japan
- Department of Genetics, SOKENDAI University, Mishima, Shizuoka, Japan
| | - Yoshihisa Oda
- Department of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan.
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8
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Ventura Santos C, Rogers SL, Carter AP. CryoET shows cofilactin filaments inside the microtubule lumen. EMBO Rep 2023; 24:e57264. [PMID: 37702953 PMCID: PMC10626427 DOI: 10.15252/embr.202357264] [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: 03/29/2023] [Revised: 08/25/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
Cytoplasmic microtubules are tubular polymers that can harbor small proteins or filaments inside their lumen. The identities of these objects and mechanisms for their accumulation have not been conclusively established. Here, we used cryogenic electron tomography of Drosophila S2 cell protrusions and found filaments inside the microtubule lumen, which resemble those reported recently in human HAP1 cells. The frequency of these filaments increased upon inhibition of the sarco/endoplasmic reticulum Ca2+ ATPase with the small molecule drug thapsigargin. Subtomogram averaging showed that the luminal filaments adopt a helical structure reminiscent of cofilin-bound actin (cofilactin). Consistent with this, we observed cofilin dephosphorylation, an activating modification, in cells under the same conditions that increased luminal filament occurrence. Furthermore, RNA interference knock-down of cofilin reduced the frequency of luminal filaments with cofilactin morphology. These results suggest that cofilin activation stimulates its accumulation on actin filaments inside the microtubule lumen.
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Affiliation(s)
| | - Stephen L Rogers
- Department of Biology and Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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9
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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10
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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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11
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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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12
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Li XX, Li H, Jin LQ, Tan YB. Exploration and Validation of Pancreatic Cancer Hub Genes Based on Weighted Gene Co-Expression Network Analysis and Immune Infiltration Score Analysis. Pharmgenomics Pers Med 2023; 16:467-480. [PMID: 37252337 PMCID: PMC10216855 DOI: 10.2147/pgpm.s403116] [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: 01/12/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023] Open
Abstract
Objective To find pancreatic cancer (PC)-related hub genes based on weighted gene co-expression network analysis (WGCNA) construction and immune infiltration score analysis and validate them immunohistochemically by clinical cases, to generate new concepts or therapeutic targets for the early diagnosis and treatment of PC. Material and Methods In this study, WGCNA and immune infiltration score were utilized to identify the relevant core modules of PC and the hub genes within these core modules. Results Using WGCNA analysis, data from PC and normal pancreas integrated with TCGA and GTEX were analyzed and brown modules were chosen from the six modules. Five hub genes, including DPYD, FXYD6, MAP6, FAM110B, and ANK2, were discovered to have differential survival significance via validation tests utilizing survival analysis curves and the GEPIA database. The DPYD gene was the only gene associated with PC survival side effects. Validation of the Human Protein Atlas (HPA) database and immunohistochemical testing of clinical samples showed positive results for DPYD expression in PC. Conclusion In this study, we identified DPYD, FXYD6, MAP6, FAM110B, and ANK2, as immune-related candidate markers for PC. Only the DPYD gene had a negative impact on the survival of PC patients. Through validation of the HPA database and immunohistochemical testing of clinical cases, we believe that the DPYD gene brings novel ideas and therapeutic targets in the diagnosis and treatment of PC.
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Affiliation(s)
- Xiao-Xi Li
- Dali University of Clinical Medicine School, Dali, Yunnan, 671000, People’s Republic of China
| | - Hong Li
- Department of Radiology, Affiliated Renhe Hospital of China Three Gorges University, Hubei, 443001, People’s Republic of China
| | - Li-Quan Jin
- Department of General Surgery, The First of Affiliated Hospital of Dali University, Dali, Yunnan, 671000, People’s Republic of China
| | - Yun-Bo Tan
- Dali University of Clinical Medicine School, Dali, Yunnan, 671000, People’s Republic of China
- Department of General Surgery, The First of Affiliated Hospital of Dali University, Dali, Yunnan, 671000, People’s Republic of China
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13
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Atkins M, Nicol X, Fassier C. Microtubule remodelling as a driving force of axon guidance and pruning. Semin Cell Dev Biol 2023; 140:35-53. [PMID: 35710759 DOI: 10.1016/j.semcdb.2022.05.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/26/2022] [Accepted: 05/31/2022] [Indexed: 01/28/2023]
Abstract
The establishment of neuronal connectivity relies on the microtubule (MT) cytoskeleton, which provides mechanical support, roads for axonal transport and mediates signalling events. Fine-tuned spatiotemporal regulation of MT functions by tubulin post-translational modifications and MT-associated proteins is critical for the coarse wiring and subsequent refinement of neuronal connectivity. The defective regulation of these processes causes a wide range of neurodevelopmental disorders associated with connectivity defects. This review focuses on recent studies unravelling how MT composition, post-translational modifications and associated proteins influence MT functions in axon guidance and/or pruning to build functional neuronal circuits. We here summarise experimental evidence supporting the key role of this network as a driving force for growth cone steering and branch-specific axon elimination. We further provide a global overview of the MT-interactors that tune developing axon behaviours, with a special emphasis on their emerging versatility in the regulation of MT dynamics/structure. Recent studies establishing the key and highly selective role of the tubulin code in the regulation of MT functions in axon pathfinding are also reported. Finally, our review highlights the emerging molecular links between these MT regulation processes and guidance signals that wire the nervous system.
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Affiliation(s)
- Melody Atkins
- INSERM, UMR-S 1270, Institut du Fer à Moulin, Sorbonne Université, F-75005 Paris, France
| | - Xavier Nicol
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
| | - Coralie Fassier
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France.
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14
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Santos CV, Rogers SL, Carter AP. CryoET shows cofilactin filaments inside the microtubule lumen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535077. [PMID: 37034688 PMCID: PMC10081314 DOI: 10.1101/2023.03.31.535077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Cytoplasmic microtubules are tubular polymers that can harbor small proteins or filaments inside their lumen. The identity of these objects and what causes their accumulation has not been conclusively established. Here, we used cryogenic electron tomography (cryoET) of Drosophila S2 cell protrusions and found filaments inside the microtubule lumen, which resemble those reported recently in human HAP1 cells. The frequency of these filaments increased upon inhibition of the sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) with the small-molecule drug thapsigargin. Subtomogram averaging showed that the luminal filaments adopt a helical structure reminiscent of cofilin-bound actin (cofilactin). Consistent with this, cofilin was activated in cells under the same conditions that increased luminal filament occurrence. Furthermore, RNAi knock-down of cofilin reduced the frequency of luminal filaments with cofilactin morphology. These results suggest that cofilin activation stimulates its accumulation on actin filaments inside the microtubule lumen.
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Affiliation(s)
| | - Stephen L. Rogers
- Department of Biology and Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill
| | - Andrew P. Carter
- MRC Laboratory of Molecular Biology, Francis Crick Ave, Cambridge, CB2 0QH, UK
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15
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Dynamics of RNA m 5C modification during brain development. Genomics 2023; 115:110604. [PMID: 36889368 DOI: 10.1016/j.ygeno.2023.110604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/26/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023]
Abstract
Post-transcriptional RNA modifications have been recognized as key regulators of neuronal differentiation and synapse development in the mammalian brain. While distinct sets of 5-methylcytosine (m5C) modified mRNAs have been detected in neuronal cells and brain tissues, no study has been performed to characterize methylated mRNA profiles in the developing brain. Here, together with regular RNA-seq, we performed transcriptome-wide bisulfite sequencing to compare RNA cytosine methylation patterns in neural stem cells (NSCs), cortical neuronal cultures, and brain tissues at three postnatal stages. Among 501 m5C sites identified, approximately 6% are consistently methylated across all five conditions. Compared to m5C sites identified in NSCs, 96% of them were hypermethylated in neurons and enriched for genes involved in positive transcriptional regulation and axon extension. In addition, brains at the early postnatal stage demonstrated substantial changes in both RNA cytosine methylation and gene expression of RNA cytosine methylation readers, writers, and erasers. Furthermore, differentially methylated transcripts were significantly enriched for genes regulating synaptic plasticity. Altogether, this study provides a brain epitranscriptomic dataset as a new resource and lays the foundation for further investigations into the role of RNA cytosine methylation during brain development.
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16
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van den Berg CM, Volkov VA, Schnorrenberg S, Huang Z, Stecker KE, Grigoriev I, Gilani S, Frikstad KAM, Patzke S, Zimmermann T, Dogterom M, Akhmanova A. CSPP1 stabilizes growing microtubule ends and damaged lattices from the luminal side. J Cell Biol 2023; 222:213861. [PMID: 36752787 PMCID: PMC9948759 DOI: 10.1083/jcb.202208062] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 12/14/2022] [Accepted: 01/13/2023] [Indexed: 02/09/2023] Open
Abstract
Microtubules are dynamic cytoskeletal polymers, and their organization and stability are tightly regulated by numerous cellular factors. While regulatory proteins controlling the formation of interphase microtubule arrays and mitotic spindles have been extensively studied, the biochemical mechanisms responsible for generating stable microtubule cores of centrioles and cilia are poorly understood. Here, we used in vitro reconstitution assays to investigate microtubule-stabilizing properties of CSPP1, a centrosome and cilia-associated protein mutated in the neurodevelopmental ciliopathy Joubert syndrome. We found that CSPP1 preferentially binds to polymerizing microtubule ends that grow slowly or undergo growth perturbations and, in this way, resembles microtubule-stabilizing compounds such as taxanes. Fluorescence microscopy and cryo-electron tomography showed that CSPP1 is deposited in the microtubule lumen and inhibits microtubule growth and shortening through two separate domains. CSPP1 also specifically recognizes and stabilizes damaged microtubule lattices. These data help to explain how CSPP1 regulates the elongation and stability of ciliary axonemes and other microtubule-based structures.
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Affiliation(s)
- Cyntha M. van den Berg
- https://ror.org/04pp8hn57Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Vladimir A. Volkov
- https://ror.org/04pp8hn57Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands,https://ror.org/02e2c7k09Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | | | - Ziqiang Huang
- EMBL Imaging Centre, EMBL-Heidelberg, Heidelberg, Germany
| | - Kelly E. Stecker
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands,Netherlands Proteomics Center, Utrecht, The Netherlands
| | - Ilya Grigoriev
- https://ror.org/04pp8hn57Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Sania Gilani
- https://ror.org/00j9c2840Department of Radiation Biology, Institute of Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway,Department of Molecular Cell Biology, Institute of Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Kari-Anne M. Frikstad
- https://ror.org/00j9c2840Department of Radiation Biology, Institute of Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | - Sebastian Patzke
- https://ror.org/00j9c2840Department of Radiation Biology, Institute of Cancer Research, Norwegian Radium Hospital, Oslo University Hospital, Oslo, Norway
| | | | - Marileen Dogterom
- https://ror.org/02e2c7k09Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Anna Akhmanova
- https://ror.org/04pp8hn57Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands,Correspondence to Anna Akhmanova:
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17
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Iwanski MK, Kapitein LC. Cellular cartography: Towards an atlas of the neuronal microtubule cytoskeleton. Front Cell Dev Biol 2023; 11:1052245. [PMID: 37035244 PMCID: PMC10073685 DOI: 10.3389/fcell.2023.1052245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 02/28/2023] [Indexed: 04/11/2023] Open
Abstract
Microtubules, one of the major components of the cytoskeleton, play a crucial role during many aspects of neuronal development and function, such as neuronal polarization and axon outgrowth. Consequently, the microtubule cytoskeleton has been implicated in many neurodevelopmental and neurodegenerative disorders. The polar nature of microtubules is quintessential for their function, allowing them to serve as tracks for long-distance, directed intracellular transport by kinesin and dynein motors. Most of these motors move exclusively towards either the plus- or minus-end of a microtubule and some have been shown to have a preference for either dynamic or stable microtubules, those bearing a particular post-translational modification or those decorated by a specific microtubule-associated protein. Thus, it becomes important to consider the interplay of these features and their combinatorial effects on transport, as well as how different types of microtubules are organized in the cell. Here, we discuss microtubule subsets in terms of tubulin isotypes, tubulin post-translational modifications, microtubule-associated proteins, microtubule stability or dynamicity, and microtubule orientation. We highlight techniques used to study these features of the microtubule cytoskeleton and, using the information from these studies, try to define the composition, role, and organization of some of these subsets in neurons.
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18
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Tsuji C, Dodding MP. Lumenal components of cytoplasmic microtubules. Biochem Soc Trans 2022; 50:1953-1962. [PMID: 36524962 DOI: 10.1042/bst20220851] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/30/2022] [Accepted: 12/01/2022] [Indexed: 07/30/2023]
Abstract
The lumen of cytoplasmic microtubules is a poorly explored expanse of intracellular space. Although typically represented in textbooks as a hollow tube, studies over several decades have shown that the microtubule lumen is occupied by a range of morphologically diverse components. These are predominantly globular particles of varying sizes which appear to exist either in isolation, bind to the microtubule wall, or form discontinuous columns that extend through the lumenal space. Actin filaments with morphologies distinct from the canonical cytoplasmic forms have also now been found within the microtubule lumen. In this review, we examine the historic literature that observed these lumenal components in tissues from diverse species and integrate it with recent cryo-electron tomography studies that have begun to identify lumenal proteins. We consider their cell and tissue distribution, possible mechanisms of incorporation, and potential functions. It is likely that continuing work in this area will open a new frontier in cytoskeletal biology.
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Affiliation(s)
- Chisato Tsuji
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, U.K
| | - Mark P Dodding
- School of Biochemistry, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, U.K
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19
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Lin Z, He Y, Qiu C, Yu Q, Huang H, Yiwen Zhang, Li W, Qiu T, Xiaoping Li. A multi-omics signature to predict the prognosis of invasive ductal carcinoma of the breast. Comput Biol Med 2022; 151:106291. [PMID: 36395590 DOI: 10.1016/j.compbiomed.2022.106291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 10/04/2022] [Accepted: 11/06/2022] [Indexed: 11/13/2022]
Abstract
BACKGROUND Precisely evaluating the prognosis of invasive ductal carcinoma (IDC) of the breast is challenging as most prognostic signatures use single-omics data based on gene or clinical information. METHODS Whole-slide images (WSIs), transcriptome, and clinical data of breast IDC were collected from the Cancer Genome Atlas Database. The cancer-associated fibroblast (CAF) gene sets were downloaded from the Molecular Signatures Database. The WSI feature was extracted by artificial feature engineering. The CAF prognostic genes were determined by the Gene Set Enrichment Analysis, the Wilcoxon test, and univariate Cox regression. The IDC patients were divided into the training and test sets. The prognostic signatures based on WSIs, IDC-CAFs, bi-omics, and tri-omics were constructed using multivariate Cox regression. The samples were divided into low- and high-risk groups according to the median risk score. The Kaplan-Meier survival and receiver operating characteristic curves were applied to validate the prediction performance of the four signatures. RESULTS In total, 508 IDC patients with complete data were included. The area under the curve (AUC) of single-omics signature based on WSI characteristics and CAFs was 0.765 and 0.775, whereas the AUC of bi-omics was 0.823. The tri-omics signature based on WSIs, CAFs, and lymph node status demonstrated the best predictive value with an AUC of 0.897. CONCLUSION The multi-omics signature based on WSIs, CAFs, and clinical characteristics showed excellent prediction ability in breast IDC patients, whose risk factors can also provide a valuable diagnostic reference for the clinical course.
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Affiliation(s)
- Zhiquan Lin
- Wuyi University, 99 Yinbin Avenue, Jiangmen, Guangdong, China
| | - Yu He
- National Drug Clinical Trial Institution, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Chaoran Qiu
- Department of Breast, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Qihe Yu
- Department of Oncology, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Hui Huang
- Department of Breast Surgery, Jiangmen Maternity & Child Health Care Hospital, Jiangmen, Guangdong, China
| | - Yiwen Zhang
- Department of Breast, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Weiwen Li
- Department of Breast, Jiangmen Central Hospital, Jiangmen, Guangdong, China
| | - Tian Qiu
- Wuyi University, 99 Yinbin Avenue, Jiangmen, Guangdong, China.
| | - Xiaoping Li
- Department of Breast, Jiangmen Central Hospital, Jiangmen, Guangdong, China.
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20
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Chai P, Rao Q, Zhang K. Multi-curve fitting and tubulin-lattice signal removal for structure determination of large microtubule-based motors. J Struct Biol 2022; 214:107897. [PMID: 36089228 DOI: 10.1016/j.jsb.2022.107897] [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: 01/23/2022] [Revised: 08/05/2022] [Accepted: 09/03/2022] [Indexed: 12/30/2022]
Abstract
Revealing high-resolution structures of microtubule-associated proteins (MAPs) is critical for understanding their fundamental roles in various cellular activities, such as cell motility and intracellular cargo transport. Nevertheless, large flexible molecular motors that dynamically bind and release microtubule networks are challenging for cryo-electron microscopy (cryo-EM). Traditional structure determination of MAPs bound to microtubules needs alignment information from the reconstruction of microtubules, which cannot be readily applied to large MAPs without a fixed binding pattern. Here, we developed a comprehensive approach to estimate the microtubule networks (multi-curve fitting), model the tubulin-lattice signals, and remove them (tubulin-lattice subtraction) from the raw cryo-EM micrographs. The approach does not require an ordered binding pattern of MAPs on microtubules, nor does it need a reconstruction of the microtubules. We demonstrated the capability of our approach using the reconstituted outer-arm dynein (OAD) bound to microtubule doublets. The tubulin-lattice subtraction improves the OAD alignment, thus leading to high-resolution reconstructions. In addition, the multi-curve fitting approach provides an accurate automatic alternative method to pick or segment filaments in 2D images and potentially in 3D tomograms. The accuracy of our approach has been demonstrated by using several other biological filaments. Our work provides a new tool to determine high-resolution structures of large MAPs bound to curved microtubule networks.
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Affiliation(s)
- Pengxin Chai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Qinhui Rao
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA.
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21
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Gasic I. Regulation of Tubulin Gene Expression: From Isotype Identity to Functional Specialization. Front Cell Dev Biol 2022; 10:898076. [PMID: 35721507 PMCID: PMC9204600 DOI: 10.3389/fcell.2022.898076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/11/2022] [Indexed: 12/14/2022] Open
Abstract
Genomes of higher eukaryotes encode a large tubulin gene superfamily consisting of at least six α and six β-tubulin isotypes. While some α and β-tubulin isotypes are ubiquitously expressed, others are cell-type specific. The subset of α and β-tubulins that is expressed in a given cell type is defined transcriptionally. But the precise mechanisms of how cells choose which α and β isotypes to express and at what level remain poorly understood. Differential expression of tubulin isotypes is particularly prominent during development and in specialized cells, suggesting that some isotypes are better suited for certain cell type-specific functions. Recent studies begin to rationalize this phenomenon, uncovering important differences in tubulin isotype behavior and their impact on the biomechanical properties of the microtubule cytoskeleton. I summarize our understanding of the regulation of tubulin isotype expression, focusing on the role of these complex regulatory pathways in building a customized microtubule network best suited for cellular needs.
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Affiliation(s)
- Ivana Gasic
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
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22
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Joshi FM, Viar GA, Pigino G, Drechsler H, Diez S. Fabrication of High Aspect Ratio Gold Nanowires within the Microtubule Lumen. NANO LETTERS 2022; 22:3659-3667. [PMID: 35446032 DOI: 10.1021/acs.nanolett.2c00255] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gold nanowires have great potential use as interconnects in electronic, photonic, and optoelectronic devices. To date, there are various fabrication strategies for gold nanowires, each one associated with particular drawbacks as they utilize high temperatures, toxic chemicals, or expensive compounds to produce nanowires of suboptimal quality. Inspired by nanowire fabrication strategies that used higher-order biopolymer structures as molds for electroless deposition of gold, we here report a strategy for the growth of gold nanowires from seed nanoparticles within the lumen of microtubules. Luminal targeting of seed particles occurs through covalently linked Fab fragments of an antibody recognizing the acetylated lysine 40 on the luminal side of α-tubulin. Gold nanowires grown by electroless deposition within the microtubule lumen exhibit a homogeneous morphology and high aspect ratios with a mean diameter of 20 nm. Our approach is fast, simple, and inexpensive and does not require toxic chemicals or other harsh conditions.
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Affiliation(s)
- Foram M Joshi
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Gonzalo Alvarez Viar
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Gaia Pigino
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Human Technopole, 20157 Milan, Italy
| | - Hauke Drechsler
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, Technische Universität Dresden, 01307 Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
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23
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Kulkarni R, Thakur A, Kumar H. Microtubule Dynamics Following Central and Peripheral Nervous System Axotomy. ACS Chem Neurosci 2022; 13:1358-1369. [PMID: 35451811 DOI: 10.1021/acschemneuro.2c00189] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Disturbance in the neuronal network leads to instability in the microtubule (MT) railroad of axons, causing hindrance in the intra-axonal transport and making it difficult to re-establish the broken network. Peripheral nervous system (PNS) neurons can stabilize their MTs, leading to the formation of regeneration-promoting structures called "growth cones". However, central nervous system (CNS) neurons lack this intrinsic reparative capability and, instead, form growth-incompetent structures called "retraction bulbs", which have a disarrayed MT network. It is evident from various studies that although axonal regeneration depends on both cell-extrinsic and cell-intrinsic factors, any therapy that aims at axonal regeneration ultimately converges onto MTs. Understanding the neuronal MT dynamics will help develop effective therapeutic strategies in diseases where the MT network gets disrupted, such as spinal cord injury, traumatic brain injury, multiple sclerosis, and amyotrophic lateral sclerosis. It is also essential to know the factors that aid or inhibit MT stabilization. In this review, we have discussed the MT dynamics postaxotomy in the CNS and PNS, and factors that can directly influence MT stability in various diseases.
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Affiliation(s)
- Riya Kulkarni
- National Institute of Pharmaceutical Education and Research, Ahmedabad, Opposite Air Force Station, Palaj, Gandhinagar, Gujarat 382355, India
| | - Akshata Thakur
- National Institute of Pharmaceutical Education and Research, Ahmedabad, Opposite Air Force Station, Palaj, Gandhinagar, Gujarat 382355, India
| | - Hemant Kumar
- National Institute of Pharmaceutical Education and Research, Ahmedabad, Opposite Air Force Station, Palaj, Gandhinagar, Gujarat 382355, India
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24
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Akhmanova A, Kapitein LC. Mechanisms of microtubule organization in differentiated animal cells. Nat Rev Mol Cell Biol 2022; 23:541-558. [PMID: 35383336 DOI: 10.1038/s41580-022-00473-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2022] [Indexed: 02/08/2023]
Abstract
Microtubules are polarized cytoskeletal filaments that serve as tracks for intracellular transport and form a scaffold that positions organelles and other cellular components and modulates cell shape and mechanics. In animal cells, the geometry, density and directionality of microtubule networks are major determinants of cellular architecture, polarity and proliferation. In dividing cells, microtubules form bipolar spindles that pull chromosomes apart, whereas in interphase cells, microtubules are organized in a cell type-specific fashion, which strongly correlates with cell physiology. In motile cells, such as fibroblasts and immune cells, microtubules are organized as radial asters, whereas in immotile epithelial and neuronal cells and in muscles, microtubules form parallel or antiparallel arrays and cortical meshworks. Here, we review recent work addressing how the formation of such microtubule networks is driven by the plethora of microtubule regulatory proteins. These include proteins that nucleate or anchor microtubule ends at different cellular structures and those that sever or move microtubules, as well as regulators of microtubule elongation, stability, bundling or modifications. The emerging picture, although still very incomplete, shows a remarkable diversity of cell-specific mechanisms that employ conserved building blocks to adjust microtubule organization in order to facilitate different cellular functions.
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Affiliation(s)
- Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands.
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25
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Atherton J, Stouffer M, Francis F, Moores CA. Visualising the cytoskeletal machinery in neuronal growth cones using cryo-electron tomography. J Cell Sci 2022; 135:274968. [PMID: 35383828 PMCID: PMC9016625 DOI: 10.1242/jcs.259234] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/02/2022] [Indexed: 12/12/2022] Open
Abstract
Neurons extend axons to form the complex circuitry of the mature brain. This depends on the coordinated response and continuous remodelling of the microtubule and F-actin networks in the axonal growth cone. Growth cone architecture remains poorly understood at nanoscales. We therefore investigated mouse hippocampal neuron growth cones using cryo-electron tomography to directly visualise their three-dimensional subcellular architecture with molecular detail. Our data showed that the hexagonal arrays of actin bundles that form filopodia penetrate and terminate deep within the growth cone interior. We directly observed the modulation of these and other growth cone actin bundles by alteration of individual F-actin helical structures. Microtubules with blunt, slightly flared or gently curved ends predominated in the growth cone, frequently contained lumenal particles and exhibited lattice defects. Investigation of the effect of absence of doublecortin, a neurodevelopmental cytoskeleton regulator, on growth cone cytoskeleton showed no major anomalies in overall growth cone organisation or in F-actin subpopulations. However, our data suggested that microtubules sustained more structural defects, highlighting the importance of microtubule integrity during growth cone migration. Summary: Cryo-electron tomographic reconstruction of neuronal growth cone subdomains reveals distinctive F-actin and microtubule cytoskeleton architectures and modulation at molecular detail.
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Affiliation(s)
- Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King's College, London SE1 1YR, UK.,Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
| | - Melissa Stouffer
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France.,Institute of Science and Technology Austria, Am campus 1, 3400 Klosterneuberg, Austria
| | - Fiona Francis
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
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26
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Foster HE, Ventura Santos C, Carter AP. A cryo-ET survey of microtubules and intracellular compartments in mammalian axons. J Cell Biol 2022; 221:e202103154. [PMID: 34878519 PMCID: PMC7612188 DOI: 10.1083/jcb.202103154] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 09/28/2021] [Accepted: 11/16/2021] [Indexed: 12/16/2022] Open
Abstract
The neuronal axon is packed with cytoskeletal filaments, membranes, and organelles, many of which move between the cell body and axon tip. Here, we used cryo-electron tomography to survey the internal components of mammalian sensory axons. We determined the polarity of the axonal microtubules (MTs) by combining subtomogram classification and visual inspection, finding MT plus and minus ends are structurally similar. Subtomogram averaging of globular densities in the MT lumen suggests they have a defined structure, which is surprising given they likely contain the disordered protein MAP6. We found the endoplasmic reticulum in axons is tethered to MTs through multiple short linkers. We surveyed membrane-bound cargos and describe unexpected internal features such as granules and broken membranes. In addition, we detected proteinaceous compartments, including numerous virus-like capsid particles. Our observations outline novel features of axonal cargos and MTs, providing a platform for identification of their constituents.
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27
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Flores-Martin JB, Bonnet LV, Palandri A, Zamanillo Hermida S, Hallak MH, Galiano MR. The 19S proteasome subunit Rpt5 reversibly associates with cold-stable microtubules in glial cells at low temperatures. FEBS Lett 2022; 596:1165-1177. [PMID: 35114005 DOI: 10.1002/1873-3468.14307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/19/2022] [Indexed: 11/12/2022]
Abstract
The ubiquitin-proteasome system (UPS) degrades intracellular proteins through the 26S proteasome. We analyzed how cold stress affects the UPS in glial cells. Together with a reduction in the 20S proteolytic activity and increased levels of polyubiquitinated proteins, exposure of glial cell cultures to cold induces a partial disassembly of the 26S proteasome. In particular, we found that Rpt5, a subunit of the 19S proteasome, relocates to cold-stable microtubules, although no apparent cytoskeletal redistribution was detected for other analyzed subunits of the 19S or 20S complexes. Furthermore, we demonstrate that both the expression of the microtubule-associated protein MAP6 and the post-translational acetylation of α-tubulin modulate the association of Rpt5 with microtubules. This reversible association could be related to functional preservation of the proteolytic complex during cold stress.
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Affiliation(s)
- Jésica B Flores-Martin
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Laura V Bonnet
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Anabela Palandri
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Sofía Zamanillo Hermida
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Marta H Hallak
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
| | - Mauricio R Galiano
- Facultad de Ciencias Químicas, Departamento de Química Biológica Ranwel Caputto, Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Universidad Nacional de Córdoba, 5000, Córdoba, Argentina
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28
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Jijumon AS, Bodakuntla S, Genova M, Bangera M, Sackett V, Besse L, Maksut F, Henriot V, Magiera MM, Sirajuddin M, Janke C. Lysate-based pipeline to characterize microtubule-associated proteins uncovers unique microtubule behaviours. Nat Cell Biol 2022; 24:253-267. [PMID: 35102268 DOI: 10.1038/s41556-021-00825-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 11/23/2021] [Indexed: 12/22/2022]
Abstract
The microtubule cytoskeleton forms complex macromolecular assemblies with a range of microtubule-associated proteins (MAPs) that have fundamental roles in cell architecture, division and motility. Determining how an individual MAP modulates microtubule behaviour is an important step in understanding the physiological roles of various microtubule assemblies. To characterize how MAPs control microtubule properties and functions, we developed an approach allowing for medium-throughput analyses of MAPs in cell-free conditions using lysates of mammalian cells. Our pipeline allows for quantitative as well as ultrastructural analyses of microtubule-MAP assemblies. Analysing 45 bona fide and potential mammalian MAPs, we uncovered previously unknown activities that lead to distinct and unique microtubule behaviours such as microtubule coiling or hook formation, or liquid-liquid phase separation along the microtubule lattice that initiates microtubule branching. We have thus established a powerful tool for a thorough characterization of a wide range of MAPs and MAP variants, thus opening avenues for the determination of mechanisms underlying their physiological roles and pathological implications.
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Affiliation(s)
- A S Jijumon
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Satish Bodakuntla
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Mariya Genova
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Mamata Bangera
- Institute for Stem Cell Science and Regenerative Medicine (inStem), Bangalore, India
| | - Violet Sackett
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | - Laetitia Besse
- Institut Curie, Université Paris-Saclay, Centre d'Imagerie Multimodale INSERM US43, CNRS UMS2016, Orsay, France
| | - Fatlinda Maksut
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Veronique Henriot
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | - Maria M Magiera
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France
- Université Paris-Saclay, CNRS UMR3348, Orsay, France
| | | | - Carsten Janke
- Institut Curie, Université PSL, CNRS UMR3348, Orsay, France.
- Université Paris-Saclay, CNRS UMR3348, Orsay, France.
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29
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Gory-Fauré S, Delaroche J, Cuveillier C, Delphin C, Arnal I. Cryo-EM Visualization of Neuronal Particles Inside Microtubules. Methods Mol Biol 2022; 2430:375-383. [PMID: 35476345 DOI: 10.1007/978-1-0716-1983-4_24] [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] [Indexed: 06/14/2023]
Abstract
Neuronal microtubules have long been known to contain intraluminal particles, called MIPs (microtubule inner proteins), most likely involved in the extreme stability of microtubules in neurons. This chapter describes a cryo-electron microscopy-based assay to visualize microtubules containing neuronal MIPs. We present two protocols to prepare MIPs-containing microtubules, using either in vitro microtubule polymerization assays or extraction of microtubules from mouse hippocampal neurons in culture.
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Affiliation(s)
- Sylvie Gory-Fauré
- Univ. Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, Grenoble, France
| | - Julie Delaroche
- Univ. Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, Grenoble, France
| | - Camille Cuveillier
- Univ. Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, Grenoble, France
| | - Christian Delphin
- Univ. Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, Grenoble, France
| | - Isabelle Arnal
- Univ. Grenoble Alpes, Inserm U1216, CNRS, Grenoble Institut Neurosciences, Grenoble, France.
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30
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Inaba H, Matsuura K. Encapsulation of Nanomaterials Inside Microtubules by Using a Tau-Derived Peptide. Methods Mol Biol 2022; 2430:243-260. [PMID: 35476337 DOI: 10.1007/978-1-0716-1983-4_16] [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] [Indexed: 06/14/2023]
Abstract
Microtubules (MTs) are tubular cytoskeletons, which are used for the various applications such as active matters and therapeutic targets. Although modification of the exterior surface of MTs is frequently used for functionalization of MTs, there was no approach to introduce molecules inside MTs. We previously developed a unique peptide binding to the inner surface of MT, which is derived from a MT-associated protein, Tau. The Tau-derived peptide (TP) can be used to introduce various nanomaterials inside MTs. Here we describe the TP-based encapsulation of fluorescent dye, gold nanoparticle, green fluorescent protein, and magnetic CoPt nanoparticles inside MTs.
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Affiliation(s)
- Hiroshi Inaba
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori, Japan.
- Centre for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan.
| | - Kazunori Matsuura
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori, Japan.
- Centre for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan.
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31
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Zuber B, Lučić V. Neurons as a model system for cryo-electron tomography. J Struct Biol X 2022; 6:100067. [PMID: 35310407 PMCID: PMC8924422 DOI: 10.1016/j.yjsbx.2022.100067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cryo-ET imaging of neurons is a versatile system for cell biology in situ. Structural and spatial localization analysis yields new insights into synaptic transmission. The synapse provides a rich environment for the development of image processing tools.
Cryo-electron tomography (Cryo-ET) provides unique opportunities to image cellular components at high resolution in their native state and environment. While many different cell types were investigated by cryo-ET, here we review application to neurons. We show that neurons are a versatile system that can be used to investigate general cellular components such as the cytoskeleton and membrane-bound organelles, in addition to neuron-specific processes such as synaptic transmission. Furthermore, the synapse provides a rich environment for the development of cryo-ET image processing tools suitable to elucidate the functional and spatial organization of compositionally and morphologically heterogeneous macromolecular complexes involved in biochemical signaling cascades, within their native, crowded cellular environments.
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32
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Boulan B, Ravanello C, Peyrel A, Bosc C, Delphin C, Appaix F, Denarier E, Kraut A, Jacquier-Sarlin M, Fournier A, Andrieux A, Gory-Fauré S, Deloulme JC. CRMP4-mediated fornix development involves Semaphorin-3E signaling pathway. eLife 2021; 10:e70361. [PMID: 34860155 PMCID: PMC8683083 DOI: 10.7554/elife.70361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 12/02/2021] [Indexed: 12/25/2022] Open
Abstract
Neurodevelopmental axonal pathfinding plays a central role in correct brain wiring and subsequent cognitive abilities. Within the growth cone, various intracellular effectors transduce axonal guidance signals by remodeling the cytoskeleton. Semaphorin-3E (Sema3E) is a guidance cue implicated in development of the fornix, a neuronal tract connecting the hippocampus to the hypothalamus. Microtubule-associated protein 6 (MAP6) has been shown to be involved in the Sema3E growth-promoting signaling pathway. In this study, we identified the collapsin response mediator protein 4 (CRMP4) as a MAP6 partner and a crucial effector in Sema3E growth-promoting activity. CRMP4-KO mice displayed abnormal fornix development reminiscent of that observed in Sema3E-KO mice. CRMP4 was shown to interact with the Sema3E tripartite receptor complex within detergent-resistant membrane (DRM) domains, and DRM domain integrity was required to transduce Sema3E signaling through the Akt/GSK3 pathway. Finally, we showed that the cytoskeleton-binding domain of CRMP4 is required for Sema3E's growth-promoting activity, suggesting that CRMP4 plays a role at the interface between Sema3E receptors, located in DRM domains, and the cytoskeleton network. As the fornix is affected in many psychiatric diseases, such as schizophrenia, our results provide new insights to better understand the neurodevelopmental components of these diseases.
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Affiliation(s)
- Benoît Boulan
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Charlotte Ravanello
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Amandine Peyrel
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Christophe Bosc
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Christian Delphin
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Florence Appaix
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Eric Denarier
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Alexandra Kraut
- Univ. Grenoble Alpes, Inserm, CEA, UMR BioSanté U1292, CNRS, CEAGrenobleFrance
| | | | - Alyson Fournier
- Department of Neurology and Neurosurgery, Montréal Neurological Institute, McGill UniversityMontréalCanada
| | - Annie Andrieux
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
| | - Sylvie Gory-Fauré
- Univ. Grenoble Alpes, Inserm, U1216, CEA, Grenoble Institut NeurosciencesGrenobleFrance
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33
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Atypical laminin spots and pull-generated microtubule-actin projections mediate Drosophila wing adhesion. Cell Rep 2021; 36:109667. [PMID: 34496252 DOI: 10.1016/j.celrep.2021.109667] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 06/11/2021] [Accepted: 08/13/2021] [Indexed: 12/12/2022] Open
Abstract
During Drosophila metamorphosis, dorsal and ventral wing surfaces adhere, separate, and reappose in a paradoxical process involving cell-matrix adhesion, matrix production and degradation, and long cellular projections. The identity of the intervening matrix, the logic behind the adhesion-reapposition cycle, and the role of projections are unknown. We find that laminin matrix spots devoid of other main basement membrane components mediate wing adhesion. Through live imaging, we show that long microtubule-actin cables grow from those adhesion spots because of hydrostatic pressure that pushes wing surfaces apart. Formation of cables resistant to pressure requires spectraplakin, Patronin, septins, and Sdb, a SAXO1/2 microtubule stabilizer expressed under control of wing intervein-selector SRF. Silkworms and dead-leaf butterflies display similar dorso-ventral projections and expression of Sdb in intervein SRF-like patterns. Our study supports the morphogenetic importance of atypical basement-membrane-related matrices and dissects matrix-cytoskeleton coordination in a process of great evolutionary significance.
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34
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Inaba H, Matsuura K. Modulation of Microtubule Properties and Functions by Encapsulation of Nanomaterials Using a Tau-Derived Peptide. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210202] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Hiroshi Inaba
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan
- Centre for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan
| | - Kazunori Matsuura
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan
- Centre for Research on Green Sustainable Chemistry, Tottori University, 4-101 Koyama-Minami, Tottori 680-8552, Japan
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35
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Nihongaki Y, Matsubayashi HT, Inoue T. A molecular trap inside microtubules probes luminal access by soluble proteins. Nat Chem Biol 2021; 17:888-895. [PMID: 33941924 PMCID: PMC8319117 DOI: 10.1038/s41589-021-00791-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 03/30/2021] [Indexed: 02/02/2023]
Abstract
The uniquely hollow structure of microtubules (MTs) confers characteristic mechanical and biological properties. Although most regulatory processes take place at the outer surface, molecular events inside MTs, such as α-tubulin acetylation, also play a critical role. However, how regulatory proteins reach the site of action remains obscure. To assess luminal accessibility, we first identified luminally positioned residues of β-tubulin that can be fused to a protein of interest. We then developed a chemically inducible technique with which cytosolic proteins can be rapidly trapped at the lumen of intact MTs in cells. A luminal trapping assay revealed that soluble proteins of moderate size can enter the lumen via diffusion through openings at the MT ends and sides. Additionally, proteins forming a complex with tubulins can be incorporated to the lumen through the plus ends. Our approach may not only illuminate this understudied territory, but may also help understand its roles in MT-mediated functions.
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Affiliation(s)
- Yuta Nihongaki
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,To whom correspondence should be addressed. ,
| | - Hideaki T. Matsubayashi
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Takanari Inoue
- Department of Cell Biology and Center for Cell Dynamics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA,To whom correspondence should be addressed. ,
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36
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Multiple layers of spatial regulation coordinate axonal cargo transport. Curr Opin Neurobiol 2021; 69:241-246. [PMID: 34171618 DOI: 10.1016/j.conb.2021.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 11/23/2022]
Abstract
Nerve axons are shaped similar to long electric wires to quickly transmit information from one end of the body to the other. To remain healthy and functional, axons depend on a wide range of cellular cargos to be transported from the neuronal cell body to its distal processes. Because of the extended distance, a sophisticated and well-organized trafficking network is required to move cargos up and down the axon. Besides motor proteins driving cargo transport, recent data revealed that subcellular membrane specializations, including the axon initial segment at the beginning of the axon and the membrane-associated periodic skeleton, which extends throughout the axonal length, are important spatial regulators of cargo traffic. In addition, tubulin modifications and microtubule-associated proteins present along the axonal cytoskeleton have been proposed to bias cargo movements. Here, we discuss the recent advances in understanding these multiple layers of regulatory mechanisms controlling axonal transport.
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37
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Wang X, Fu Y, Beatty WL, Ma M, Brown A, Sibley LD, Zhang R. Cryo-EM structure of cortical microtubules from human parasite Toxoplasma gondii identifies their microtubule inner proteins. Nat Commun 2021; 12:3065. [PMID: 34031406 PMCID: PMC8144581 DOI: 10.1038/s41467-021-23351-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/21/2021] [Indexed: 02/04/2023] Open
Abstract
In living cells, microtubules (MTs) play pleiotropic roles, which require very different mechanical properties. Unlike the dynamic MTs found in the cytoplasm of metazoan cells, the specialized cortical MTs from Toxoplasma gondii, a prevalent human pathogen, are extraordinarily stable and resistant to detergent and cold treatments. Using single-particle cryo-EM, we determine their ex vivo structure and identify three proteins (TrxL1, TrxL2 and SPM1) as bona fide microtubule inner proteins (MIPs). These three MIPs form a mesh on the luminal surface and simultaneously stabilize the tubulin lattice in both longitudinal and lateral directions. Consistent with previous observations, deletion of the identified MIPs compromises MT stability and integrity under challenges by chemical treatments. We also visualize a small molecule like density at the Taxol-binding site of β-tubulin. Our results provide the structural basis to understand the stability of cortical MTs and suggest an evolutionarily conserved mechanism of MT stabilization from the inside.
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Affiliation(s)
- Xiangli Wang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Yong Fu
- Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA
| | - Meisheng Ma
- 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
| | - L David Sibley
- Department of Molecular Microbiology, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, School of Medicine, St. Louis, MO, USA.
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38
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Cuveillier C, Boulan B, Ravanello C, Denarier E, Deloulme JC, Gory-Fauré S, Delphin C, Bosc C, Arnal I, Andrieux A. Beyond Neuronal Microtubule Stabilization: MAP6 and CRMPS, Two Converging Stories. Front Mol Neurosci 2021; 14:665693. [PMID: 34025352 PMCID: PMC8131560 DOI: 10.3389/fnmol.2021.665693] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/09/2021] [Indexed: 12/21/2022] Open
Abstract
The development and function of the central nervous system rely on the microtubule (MT) and actin cytoskeletons and their respective effectors. Although the structural role of the cytoskeleton has long been acknowledged in neuronal morphology and activity, it was recently recognized to play the role of a signaling platform. Following this recognition, research into Microtubule Associated Proteins (MAPs) diversified. Indeed, historically, structural MAPs—including MAP1B, MAP2, Tau, and MAP6 (also known as STOP);—were identified and described as MT-binding and -stabilizing proteins. Extensive data obtained over the last 20 years indicated that these structural MAPs could also contribute to a variety of other molecular roles. Among multi-role MAPs, MAP6 provides a striking example illustrating the diverse molecular and cellular properties of MAPs and showing how their functional versatility contributes to the central nervous system. In this review, in addition to MAP6’s effect on microtubules, we describe its impact on the actin cytoskeleton, on neuroreceptor homeostasis, and its involvement in signaling pathways governing neuron development and maturation. We also discuss its roles in synaptic plasticity, brain connectivity, and cognitive abilities, as well as the potential relationships between the integrated brain functions of MAP6 and its molecular activities. In parallel, the Collapsin Response Mediator Proteins (CRMPs) are presented as examples of how other proteins, not initially identified as MAPs, fall into the broader MAP family. These proteins bind MTs as well as exhibiting molecular and cellular properties very similar to MAP6. Finally, we briefly summarize the multiple similarities between other classical structural MAPs and MAP6 or CRMPs.In summary, this review revisits the molecular properties and the cellular and neuronal roles of the classical MAPs, broadening our definition of what constitutes a MAP.
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39
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Spinks GM, Martino ND, Naficy S, Shepherd DJ, Foroughi J. Dual high-stroke and high-work capacity artificial muscles inspired by DNA supercoiling. Sci Robot 2021; 6:6/53/eabf4788. [PMID: 34043569 DOI: 10.1126/scirobotics.abf4788] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/06/2021] [Indexed: 11/02/2022]
Abstract
Powering miniature robots using actuating materials that mimic skeletal muscle is attractive because conventional mechanical drive systems cannot be readily downsized. However, muscle is not the only mechanically active system in nature, and the thousandfold contraction of eukaryotic DNA into the cell nucleus suggests an alternative mechanism for high-stroke artificial muscles. Our analysis reveals that the compaction of DNA generates a mass-normalized mechanical work output exceeding that of skeletal muscle, and this result inspired the development of composite double-helix fibers that reversibly convert twist to DNA-like plectonemic or solenoidal supercoils by simple swelling and deswelling. Our modeling-optimized twisted fibers give contraction strokes as high as 90% with a maximum gravimetric work 36 times higher than skeletal muscle. We found that our supercoiling coiled fibers simultaneously provide high stroke and high work capacity, which is rare in other artificial muscles.
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Affiliation(s)
- Geoffrey M Spinks
- Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia.
| | - Nicolas D Martino
- Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Sina Naficy
- School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia
| | - David J Shepherd
- Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Javad Foroughi
- Australian Institute for Innovative Materials, University of Wollongong, Wollongong, NSW 2522, Australia
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40
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Deurveilher S, Ko KR, Saumure BSC, Robertson GS, Rusak B, Semba K. Altered circadian activity and sleep/wake rhythms in the stable tubule only polypeptide (STOP) null mouse model of schizophrenia. Sleep 2021; 44:5981350. [PMID: 33186470 DOI: 10.1093/sleep/zsaa237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/14/2020] [Indexed: 12/27/2022] Open
Abstract
Sleep and circadian rhythm disruptions commonly occur in individuals with schizophrenia. Stable tubule only polypeptide (STOP) knockout (KO) mice show behavioral impairments resembling symptoms of schizophrenia. We previously reported that STOP KO mice slept less and had more fragmented sleep and waking than wild-type littermates under a light/dark (LD) cycle. Here, we assessed the circadian phenotype of male STOP KO mice by examining wheel-running activity rhythms and EEG/EMG-defined sleep/wake states under both LD and constant darkness (DD) conditions. Wheel-running activity rhythms in KO and wild-type mice were similarly entrained in LD, and had similar free-running periods in DD. The phase delay shift in response to a light pulse given early in the active phase under DD was preserved in KO mice. KO mice had markedly lower activity levels, lower amplitude activity rhythms, less stable activity onsets, and more fragmented activity than wild-type mice in both lighting conditions. KO mice also spent more time awake and less time in rapid eye movement sleep (REMS) and non-REMS (NREMS) in both LD and DD conditions, with the decrease in NREMS concentrated in the active phase. KO mice also showed altered EEG features and higher amplitude rhythms in wake and NREMS (but not REMS) amounts in both lighting conditions, with a longer free-running period in DD, compared to wild-type mice. These results indicate that the STOP null mutation in mice altered the regulation of sleep/wake physiology and activity rhythm expression, but did not grossly disrupt circadian mechanisms.
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Affiliation(s)
- Samuel Deurveilher
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kristin Robin Ko
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada
| | - Brock St C Saumure
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - George S Robertson
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Pharmacology, Dalhousie University, Halifax, NS, Canada
| | - Benjamin Rusak
- Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
| | - Kazue Semba
- Department of Medical Neuroscience, Dalhousie University, Halifax, NS, Canada.,Department of Psychiatry, Dalhousie University, Halifax, NS, Canada.,Department of Psychology & Neuroscience, Dalhousie University, Halifax, NS, Canada
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41
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Cuveillier C, Saoudi Y, Arnal I, Delphin C. Imaging Microtubules in vitro at High Resolution while Preserving their Structure. Bio Protoc 2021; 11:e3968. [PMID: 33889662 DOI: 10.21769/bioprotoc.3968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 11/02/2022] Open
Abstract
Microtubules (MT) are the most rigid component of the cytoskeleton. Nevertheless, they often appear highly curved in the cellular context and the mechanisms governing their overall shape are poorly understood. Currently, in vitro microtubule analysis relies primarily on electron microscopy for its high resolution and Total Internal Reflection Fluorescence (TIRF) microscopy for its ability to image live fluorescently-labelled microtubules and associated proteins. For three-dimensional analyses of microtubules with micrometer curvatures, we have developed an assay in which MTs are polymerized in vitro from MT seeds adhered to a glass slide in a manner similar to conventional TIRF microscopy protocols. Free fluorescent molecules are removed and the MTs are fixed by perfusion. The MTs can then be observed using a confocal microscope with an Airyscan module for higher resolution. This protocol allows the imaging of microtubules that have retained their original three-dimensional shape and is compatible with high-resolution immunofluorescence detection.
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Affiliation(s)
- Camille Cuveillier
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, GIN, France
| | - Yasmina Saoudi
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, GIN, France
| | - Isabelle Arnal
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, GIN, France
| | - Christian Delphin
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, GIN, France
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Parato J, Bartolini F. The microtubule cytoskeleton at the synapse. Neurosci Lett 2021; 753:135850. [PMID: 33775740 DOI: 10.1016/j.neulet.2021.135850] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 12/13/2022]
Abstract
In neurons, microtubules (MTs) provide routes for transport throughout the cell and structural support for dendrites and axons. Both stable and dynamic MTs are necessary for normal neuronal functions. Research in the last two decades has demonstrated that MTs play additional roles in synaptic structure and function in both pre- and postsynaptic elements. Here, we review current knowledge of the functions that MTs perform in excitatory and inhibitory synapses, as well as in the neuromuscular junction and other specialized synapses, and discuss the implications that this knowledge may have in neurological disease.
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Affiliation(s)
- Julie Parato
- Columbia University Medical Center, Department of Pathology & Cell Biology, 630 West 168(th)Street, P&S 15-421, NY, NY, 10032, United States; SUNY Empire State College, Department of Natural Sciences, 177 Livingston Street, Brooklyn, NY, 11201, United States
| | - Francesca Bartolini
- Columbia University Medical Center, Department of Pathology & Cell Biology, 630 West 168(th)Street, P&S 15-421, NY, NY, 10032, United States.
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43
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Regulation of actin dynamics in dendritic spines: Nanostructure, molecular mobility, and signaling mechanisms. Mol Cell Neurosci 2020; 109:103564. [DOI: 10.1016/j.mcn.2020.103564] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/04/2020] [Indexed: 12/16/2022] Open
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Borys F, Joachimiak E, Krawczyk H, Fabczak H. Intrinsic and Extrinsic Factors Affecting Microtubule Dynamics in Normal and Cancer Cells. Molecules 2020; 25:E3705. [PMID: 32823874 PMCID: PMC7464520 DOI: 10.3390/molecules25163705] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/03/2020] [Accepted: 08/08/2020] [Indexed: 12/18/2022] Open
Abstract
Microtubules (MTs), highly dynamic structures composed of α- and β-tubulin heterodimers, are involved in cell movement and intracellular traffic and are essential for cell division. Within the cell, MTs are not uniform as they can be composed of different tubulin isotypes that are post-translationally modified and interact with different microtubule-associated proteins (MAPs). These diverse intrinsic factors influence the dynamics of MTs. Extrinsic factors such as microtubule-targeting agents (MTAs) can also affect MT dynamics. MTAs can be divided into two main categories: microtubule-stabilizing agents (MSAs) and microtubule-destabilizing agents (MDAs). Thus, the MT skeleton is an important target for anticancer therapy. This review discusses factors that determine the microtubule dynamics in normal and cancer cells and describes microtubule-MTA interactions, highlighting the importance of tubulin isoform diversity and post-translational modifications in MTA responses and the consequences of such a phenomenon, including drug resistance development.
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Affiliation(s)
- Filip Borys
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
- Department of Organic Chemistry, Faculty of Chemistry, Warsaw University of Technology, 3 Noakowskiego Street, 00-664 Warsaw, Poland;
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
| | - Hanna Krawczyk
- Department of Organic Chemistry, Faculty of Chemistry, Warsaw University of Technology, 3 Noakowskiego Street, 00-664 Warsaw, Poland;
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland;
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Boulan B, Beghin A, Ravanello C, Deloulme JC, Gory-Fauré S, Andrieux A, Brocard J, Denarier E. AutoNeuriteJ: An ImageJ plugin for measurement and classification of neuritic extensions. PLoS One 2020; 15:e0234529. [PMID: 32673338 PMCID: PMC7365462 DOI: 10.1371/journal.pone.0234529] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 06/29/2020] [Indexed: 01/02/2023] Open
Abstract
Morphometry characterization is an important procedure in describing neuronal cultures and identifying phenotypic differences. This task usually requires labor-intensive measurements and the classification of numerous neurites from large numbers of neurons in culture. To automate these measurements, we wrote AutoNeuriteJ, an imageJ/Fiji plugin that measures and classifies neurites from a very large number of neurons. We showed that AutoNeuriteJ is able to detect variations of neuritic growth induced by several compounds known to affect the neuronal growth. In these experiments measurement of more than 5000 mouse neurons per conditions was obtained within a few hours. Moreover, by analyzing mouse neurons deficient for the microtubule associated protein 6 (MAP6) and wild type neurons we illustrate that AutoNeuriteJ is capable to detect subtle phenotypic difference in axonal length. Overall the use of AutoNeuriteJ will provide rapid, unbiased and accurate measurement of neuron morphologies.
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Affiliation(s)
- Benoit Boulan
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
| | - Anne Beghin
- MechanoBiology Institute (MBI) at NUS Singapore MBI, T-Lab, Singapore
| | - Charlotte Ravanello
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
| | | | - Sylvie Gory-Fauré
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
| | - Annie Andrieux
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
| | - Jacques Brocard
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
| | - Eric Denarier
- Univ. Grenoble Alpes, Inserm U1216, CEA, Grenoble Institut Neurosciences, Grenoble, France
- * E-mail:
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Prokop A. Cytoskeletal organization of axons in vertebrates and invertebrates. J Cell Biol 2020; 219:e201912081. [PMID: 32369543 PMCID: PMC7337489 DOI: 10.1083/jcb.201912081] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 04/13/2020] [Accepted: 04/14/2020] [Indexed: 12/11/2022] Open
Abstract
The maintenance of axons for the lifetime of an organism requires an axonal cytoskeleton that is robust but also flexible to adapt to mechanical challenges and to support plastic changes of axon morphology. Furthermore, cytoskeletal organization has to adapt to axons of dramatically different dimensions, and to their compartment-specific requirements in the axon initial segment, in the axon shaft, at synapses or in growth cones. To understand how the cytoskeleton caters to these different demands, this review summarizes five decades of electron microscopic studies. It focuses on the organization of microtubules and neurofilaments in axon shafts in both vertebrate and invertebrate neurons, as well as the axon initial segments of vertebrate motor- and interneurons. Findings from these ultrastructural studies are being interpreted here on the basis of our contemporary molecular understanding. They strongly suggest that axon architecture in animals as diverse as arthropods and vertebrates is dependent on loosely cross-linked bundles of microtubules running all along axons, with only minor roles played by neurofilaments.
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Affiliation(s)
- Andreas Prokop
- School of Biology, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
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