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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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2
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Voelzmann A, Sanchez-Soriano N. Drosophila Primary Neuronal Cultures as a Useful Cellular Model to Study and Image Axonal Transport. Methods Mol Biol 2022; 2431:429-449. [PMID: 35412291 DOI: 10.1007/978-1-0716-1990-2_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The use of primary neuronal cultures generated from Drosophila tissue provides a powerful model for studies of transport mechanisms. Cultured fly neurons provide similarly detailed subcellular resolution and applicability of pharmacology or fluorescent dyes as mammalian primary neurons. As an experimental advantage for the mechanistic dissection of transport, fly primary neurons can be combined with the fast and highly efficient combinatorial genetics of Drosophila, and genetic tools for the manipulation of virtually every fly gene are readily available. This strategy can be performed in parallel to in vivo transport studies to address relevance of any findings. Here we will describe the generation of primary neuronal cultures from Drosophila embryos and larvae, the use of external fluorescent dyes and genetic tools to label cargo, and the key strategies for live imaging and subsequent analysis.
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Affiliation(s)
- André Voelzmann
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
| | - Natalia Sanchez-Soriano
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool, UK.
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3
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Grintsevich EE, Ahmed G, Ginosyan AA, Wu H, Rich SK, Reisler E, Terman JR. Profilin and Mical combine to impair F-actin assembly and promote disassembly and remodeling. Nat Commun 2021; 12:5542. [PMID: 34545088 PMCID: PMC8452626 DOI: 10.1038/s41467-021-25781-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/24/2021] [Indexed: 11/30/2022] Open
Abstract
Cellular events require the spatiotemporal interplay between actin assembly and actin disassembly. Yet, how different factors promote the integration of these two opposing processes is unclear. In particular, cellular monomeric (G)-actin is complexed with profilin, which inhibits spontaneous actin nucleation but fuels actin filament (F-actin) assembly by elongation-promoting factors (formins, Ena/VASP). In contrast, site-specific F-actin oxidation by Mical promotes F-actin disassembly and release of polymerization-impaired Mical-oxidized (Mox)-G-actin. Here we find that these two opposing processes connect with one another to orchestrate actin/cellular remodeling. Specifically, we find that profilin binds Mox-G-actin, yet these complexes do not fuel elongation factors’-mediated F-actin assembly, but instead inhibit polymerization and promote further Mox-F-actin disassembly. Using Drosophila as a model system, we show that similar profilin–Mical connections occur in vivo – where they underlie F-actin/cellular remodeling that accompanies Semaphorin–Plexin cellular/axon repulsion. Thus, profilin and Mical combine to impair F-actin assembly and promote F-actin disassembly, while concomitantly facilitating cellular remodeling and plasticity. Actin-based structures in cells and tissues are built and maintained through a poorly understood balance between assembly and disassembly. Here, our findings provide insights into how factors known to promote these opposing effects dynamically integrate to shape cells and tissue systems.
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Affiliation(s)
- Elena E Grintsevich
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA. .,Department of Chemistry and Biochemistry, California State University, Long Beach (CSULB), Long Beach, CA, 90840, USA.
| | - Giasuddin Ahmed
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Anush A Ginosyan
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - Heng Wu
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Shannon K Rich
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA. .,Molecular Biology Institute, UCLA, Los Angeles, CA, 90095, USA.
| | - Jonathan R Terman
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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4
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Szikora S, Görög P, Kozma C, Mihály J. Drosophila Models Rediscovered with Super-Resolution Microscopy. Cells 2021; 10:1924. [PMID: 34440693 PMCID: PMC8391832 DOI: 10.3390/cells10081924] [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: 07/02/2021] [Revised: 07/22/2021] [Accepted: 07/27/2021] [Indexed: 11/25/2022] Open
Abstract
With the advent of super-resolution microscopy, we gained a powerful toolbox to bridge the gap between the cellular- and molecular-level analysis of living organisms. Although nanoscopy is broadly applicable, classical model organisms, such as fruit flies, worms and mice, remained the leading subjects because combining the strength of sophisticated genetics, biochemistry and electrophysiology with the unparalleled resolution provided by super-resolution imaging appears as one of the most efficient approaches to understanding the basic cell biological questions and the molecular complexity of life. Here, we summarize the major nanoscopic techniques and illustrate how these approaches were used in Drosophila model systems to revisit a series of well-known cell biological phenomena. These investigations clearly demonstrate that instead of simply achieving an improvement in image quality, nanoscopy goes far beyond with its immense potential to discover novel structural and mechanistic aspects. With the examples of synaptic active zones, centrosomes and sarcomeres, we will explain the instrumental role of super-resolution imaging pioneered in Drosophila in understanding fundamental subcellular constituents.
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Affiliation(s)
- Szilárd Szikora
- Institute of Genetics, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
| | - Péter Görög
- Institute of Genetics, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
- Doctoral School of Multidisciplinary Medical Science, Faculty of Medicine, University of Szeged, H-6725 Szeged, Hungary
| | - Csaba Kozma
- Foundation for the Future of Biomedical Sciences in Szeged, Szeged Scientists Academy, Pálfy u. 52/d, H-6725 Szeged, Hungary;
| | - József Mihály
- Institute of Genetics, Biological Research Centre, Temesvári krt. 62, H-6726 Szeged, Hungary;
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary
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5
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Hahn I, Voelzmann A, Parkin J, Fülle JB, Slater PG, Lowery LA, Sanchez-Soriano N, Prokop A. Tau, XMAP215/Msps and Eb1 co-operate interdependently to regulate microtubule polymerisation and bundle formation in axons. PLoS Genet 2021; 17:e1009647. [PMID: 34228717 PMCID: PMC8284659 DOI: 10.1371/journal.pgen.1009647] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/16/2021] [Accepted: 06/07/2021] [Indexed: 11/18/2022] Open
Abstract
The formation and maintenance of microtubules requires their polymerisation, but little is known about how this polymerisation is regulated in cells. Focussing on the essential microtubule bundles in axons of Drosophila and Xenopus neurons, we show that the plus-end scaffold Eb1, the polymerase XMAP215/Msps and the lattice-binder Tau co-operate interdependently to promote microtubule polymerisation and bundle organisation during axon development and maintenance. Eb1 and XMAP215/Msps promote each other's localisation at polymerising microtubule plus-ends. Tau outcompetes Eb1-binding along microtubule lattices, thus preventing depletion of Eb1 tip pools. The three factors genetically interact and show shared mutant phenotypes: reductions in axon growth, comet sizes, comet numbers and comet velocities, as well as prominent deterioration of parallel microtubule bundles into disorganised curled conformations. This microtubule curling is caused by Eb1 plus-end depletion which impairs spectraplakin-mediated guidance of extending microtubules into parallel bundles. Our demonstration that Eb1, XMAP215/Msps and Tau co-operate during the regulation of microtubule polymerisation and bundle organisation, offers new conceptual explanations for developmental and degenerative axon pathologies.
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Affiliation(s)
- Ines Hahn
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester, United Kingdom
| | - Andre Voelzmann
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester, United Kingdom
| | - Jill Parkin
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester, United Kingdom
| | - Judith B. Fülle
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester, United Kingdom
| | - Paula G. Slater
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Laura Anne Lowery
- Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Natalia Sanchez-Soriano
- Department of Molecular Physiology & Cell Signalling, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Andreas Prokop
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, Manchester, United Kingdom
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6
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Yaniv SP, Meltzer H, Alyagor I, Schuldiner O. Developmental axon regrowth and primary neuron sprouting utilize distinct actin elongation factors. J Cell Biol 2021; 219:151569. [PMID: 32191286 PMCID: PMC7199854 DOI: 10.1083/jcb.201903181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 11/06/2019] [Accepted: 02/14/2020] [Indexed: 01/23/2023] Open
Abstract
Intrinsic neurite growth potential is a key determinant of neuronal regeneration efficiency following injury. The stereotypical remodeling of Drosophila γ-neurons includes developmental regrowth of pruned axons to form adult specific connections, thereby offering a unique system to uncover growth potential regulators. Motivated by the dynamic expression in remodeling γ-neurons, we focus here on the role of actin elongation factors as potential regulators of developmental axon regrowth. We found that regrowth in vivo requires the actin elongation factors Ena and profilin, but not the formins that are expressed in γ-neurons. In contrast, primary γ-neuron sprouting in vitro requires profilin and the formin DAAM, but not Ena. Furthermore, we demonstrate that DAAM can compensate for the loss of Ena in vivo. Similarly, DAAM mutants express invariably high levels of Ena in vitro. Thus, we show that different linear actin elongation factors function in distinct contexts even within the same cell type and that they can partially compensate for each other.
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Affiliation(s)
- Shiri P Yaniv
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Hagar Meltzer
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Idan Alyagor
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
| | - Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, Rehovot, Israel
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7
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Pinto-Costa R, Sousa SC, Leite SC, Nogueira-Rodrigues J, Ferreira da Silva T, Machado D, Marques J, Costa AC, Liz MA, Bartolini F, Brites P, Costell M, Fässler R, Sousa MM. Profilin 1 delivery tunes cytoskeletal dynamics toward CNS axon regeneration. J Clin Invest 2020; 130:2024-2040. [PMID: 31945017 DOI: 10.1172/jci125771] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
After trauma, regeneration of adult CNS axons is abortive, causing devastating neurologic deficits. Despite progress in rehabilitative care, there is no effective treatment that stimulates axonal growth following injury. Using models with different regenerative capacities, followed by gain- and loss-of-function analysis, we identified profilin 1 (Pfn1) as a coordinator of actin and microtubules (MTs), powering axonal growth and regeneration. In growth cones, Pfn1 increased actin retrograde flow, MT growth speed, and invasion of filopodia by MTs, orchestrating cytoskeletal dynamics toward axonal growth. In vitro, active Pfn1 promoted MT growth in a formin-dependent manner, whereas localization of MTs to growth cone filopodia was facilitated by direct MT binding and interaction with formins. In vivo, Pfn1 ablation limited regeneration of growth-competent axons after sciatic nerve and spinal cord injury. Adeno-associated viral (AAV) delivery of constitutively active Pfn1 to rodents promoted axonal regeneration, neuromuscular junction maturation, and functional recovery of injured sciatic nerves, and increased the ability of regenerating axons to penetrate the inhibitory spinal cord glial scar. Thus, we identify Pfn1 as an important regulator of axonal regeneration and suggest that AAV-mediated delivery of constitutively active Pfn1, together with the identification of modulators of Pfn1 activity, should be considered to treat the injured nervous system.
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Affiliation(s)
- Rita Pinto-Costa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sara C Sousa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Sérgio C Leite
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Joana Nogueira-Rodrigues
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and.,Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Tiago Ferreira da Silva
- NeuroLipid Biology Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, Universidade do Porto, Porto, Portugal
| | - Diana Machado
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Joana Marques
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Ana Catarina Costa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Márcia A Liz
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
| | - Francesca Bartolini
- Department of Pathology and Cell Biology, Columbia University, New York, New York, USA
| | - Pedro Brites
- NeuroLipid Biology Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, Universidade do Porto, Porto, Portugal
| | - Mercedes Costell
- Department of Biochemistry and Molecular Biology and Estructura de Reserca Interdisciplinar en Biotecnologia i Biomedicina, Universitat de València, Valencia, Spain
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Plank Institute of Biochemistry, Martinsried, Germany
| | - Mónica M Sousa
- Nerve Regeneration Group, Program in Neurobiology and Neurologic Disorders, Instituto de Biologia Molecular e Celular (IBMC) and Instituto de Inovação e Investigação em Saúde, and
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8
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Transthyretin interacts with actin regulators in a Drosophila model of familial amyloid polyneuropathy. Sci Rep 2020; 10:13596. [PMID: 32788615 PMCID: PMC7423984 DOI: 10.1038/s41598-020-70377-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 07/23/2020] [Indexed: 11/23/2022] Open
Abstract
Familial amyloid polyneuropathy (FAP) is a neurodegenerative disorder whose major hallmark is the deposition of mutated transthyretin (TTR) in the form of amyloid fibrils in the peripheral nervous system (PNS). The exposure of PNS axons to extracellular TTR deposits leads to an axonopathy that culminates in neuronal death. However, the molecular mechanisms underlying TTR-induced neurodegeneration are still unclear, despite the extensive studies in vertebrate models. In this work we used a Drosophila FAP model, based on the expression of the amyloidogenic TTR (V30M) in the fly retina, to uncover genetic interactions with cytoskeleton regulators. We show that TTR interacts with actin regulators and induces cytoskeleton alterations, leading to axonal defects. Moreover, our study pinpoints an interaction between TTRV30M and members of Rho GTPase signaling pathways, the major actin regulators. Based on these findings we propose that actin cytoskeleton alterations may mediate the axonopathy observed in FAP patients, and highlight a molecular pathway, mediated by Rho GTPases, underlying TTR-induced neurodegeneration. We expect this work to prompt novel studies and approaches towards FAP therapy.
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9
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Pimm ML, Hotaling J, Henty-Ridilla JL. Profilin choreographs actin and microtubules in cells and cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 355:155-204. [PMID: 32859370 PMCID: PMC7461721 DOI: 10.1016/bs.ircmb.2020.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Actin and microtubules play essential roles in aberrant cell processes that define and converge in cancer including: signaling, morphology, motility, and division. Actin and microtubules do not directly interact, however shared regulators coordinate these polymers. While many of the individual proteins important for regulating and choreographing actin and microtubule behaviors have been identified, the way these molecules collaborate or fail in normal or disease contexts is not fully understood. Decades of research focus on Profilin as a signaling molecule, lipid-binding protein, and canonical regulator of actin assembly. Recent reports demonstrate that Profilin also regulates microtubule dynamics and polymerization. Thus, Profilin can coordinate both actin and microtubule polymer systems. Here we reconsider the biochemical and cellular roles for Profilin with a focus on the essential cytoskeletal-based cell processes that go awry in cancer. We also explore how the use of model organisms has helped to elucidate mechanisms that underlie the regulatory essence of Profilin in vivo and in the context of disease.
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Affiliation(s)
- Morgan L Pimm
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States
| | - Jessica Hotaling
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States
| | - Jessica L Henty-Ridilla
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States; Department of Biochemistry and Molecular Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States.
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10
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Qu Y, Hahn I, Lees M, Parkin J, Voelzmann A, Dorey K, Rathbone A, Friel CT, Allan VJ, Okenve-Ramos P, Sanchez-Soriano N, Prokop A. Efa6 protects axons and regulates their growth and branching by inhibiting microtubule polymerisation at the cortex. eLife 2019; 8:e50319. [PMID: 31718774 PMCID: PMC6884004 DOI: 10.7554/elife.50319] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 11/06/2019] [Indexed: 12/12/2022] Open
Abstract
Cortical collapse factors affect microtubule (MT) dynamics at the plasma membrane. They play important roles in neurons, as suggested by inhibition of axon growth and regeneration through the ARF activator Efa6 in C. elegans, and by neurodevelopmental disorders linked to the mammalian kinesin Kif21A. How cortical collapse factors influence axon growth is little understood. Here we studied them, focussing on the function of Drosophila Efa6 in experimentally and genetically amenable fly neurons. First, we show that Drosophila Efa6 can inhibit MTs directly without interacting molecules via an N-terminal 18 amino acid motif (MT elimination domain/MTED) that binds tubulin and inhibits microtubule growth in vitro and cells. If N-terminal MTED-containing fragments are in the cytoplasm they abolish entire microtubule networks of mouse fibroblasts and whole axons of fly neurons. Full-length Efa6 is membrane-attached, hence primarily blocks MTs in the periphery of fibroblasts, and explorative MTs that have left axonal bundles in neurons. Accordingly, loss of Efa6 causes an increase of explorative MTs: in growth cones they enhance axon growth, in axon shafts they cause excessive branching, as well as atrophy through perturbations of MT bundles. Efa6 over-expression causes the opposite phenotypes. Taken together, our work conceptually links molecular and sub-cellular functions of cortical collapse factors to axon growth regulation and reveals new roles in axon branching and in the prevention of axonal atrophy. Furthermore, the MTED delivers a promising tool that can be used to inhibit MTs in a compartmentalised fashion when fusing it to specifically localising protein domains.
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Affiliation(s)
- Yue Qu
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Ines Hahn
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Meredith Lees
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Jill Parkin
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - André Voelzmann
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Karel Dorey
- Faculty of Biology, Medicine and Health, School of Medical SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Alex Rathbone
- School of Life Sciences, Faculty of Medicine and Health SciencesThe University of NottinghamNottinghamUnited Kingdom
| | - Claire T Friel
- School of Life Sciences, Faculty of Medicine and Health SciencesThe University of NottinghamNottinghamUnited Kingdom
| | - Victoria J Allan
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
| | - Pilar Okenve-Ramos
- Department of Cellular and Molecular Physiology,Institute of Translational MedicineUniversity of LiverpoolLiverpoolUnited Kingdom
| | - Natalia Sanchez-Soriano
- Department of Cellular and Molecular Physiology,Institute of Translational MedicineUniversity of LiverpoolLiverpoolUnited Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological SciencesThe University of ManchesterManchesterUnited Kingdom
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11
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Hahn I, Voelzmann A, Liew YT, Costa-Gomes B, Prokop A. The model of local axon homeostasis - explaining the role and regulation of microtubule bundles in axon maintenance and pathology. Neural Dev 2019; 14:11. [PMID: 31706327 PMCID: PMC6842214 DOI: 10.1186/s13064-019-0134-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Axons are the slender, cable-like, up to meter-long projections of neurons that electrically wire our brains and bodies. In spite of their challenging morphology, they usually need to be maintained for an organism's lifetime. This makes them key lesion sites in pathological processes of ageing, injury and neurodegeneration. The morphology and physiology of axons crucially depends on the parallel bundles of microtubules (MTs), running all along to serve as their structural backbones and highways for life-sustaining cargo transport and organelle dynamics. Understanding how these bundles are formed and then maintained will provide important explanations for axon biology and pathology. Currently, much is known about MTs and the proteins that bind and regulate them, but very little about how these factors functionally integrate to regulate axon biology. As an attempt to bridge between molecular mechanisms and their cellular relevance, we explain here the model of local axon homeostasis, based on our own experiments in Drosophila and published data primarily from vertebrates/mammals as well as C. elegans. The model proposes that (1) the physical forces imposed by motor protein-driven transport and dynamics in the confined axonal space, are a life-sustaining necessity, but pose a strong bias for MT bundles to become disorganised. (2) To counterbalance this risk, MT-binding and -regulating proteins of different classes work together to maintain and protect MT bundles as necessary transport highways. Loss of balance between these two fundamental processes can explain the development of axonopathies, in particular those linking to MT-regulating proteins, motors and transport defects. With this perspective in mind, we hope that more researchers incorporate MTs into their work, thus enhancing our chances of deciphering the complex regulatory networks that underpin axon biology and pathology.
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Affiliation(s)
- Ines Hahn
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - André Voelzmann
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Yu-Ting Liew
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Beatriz Costa-Gomes
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK.
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12
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Mouly L, Gilhodes J, Lemarié A, Cohen-Jonathan Moyal E, Toulas C, Favre G, Sordet O, Monferran S. The RND1 Small GTPase: Main Functions and Emerging Role in Oncogenesis. Int J Mol Sci 2019; 20:ijms20153612. [PMID: 31344837 PMCID: PMC6696182 DOI: 10.3390/ijms20153612] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/10/2019] [Accepted: 07/21/2019] [Indexed: 02/07/2023] Open
Abstract
The Rho GTPase family can be classified into classic and atypical members. Classic members cycle between an inactive Guanosine DiPhosphate -bound state and an active Guanosine TriPhosphate-bound state. Atypical Rho GTPases, such as RND1, are predominantly in an active GTP-bound conformation. The role of classic members in oncogenesis has been the subject of numerous studies, while that of atypical members has been less explored. Besides the roles of RND1 in healthy tissues, recent data suggest that RND1 is involved in oncogenesis and response to cancer therapeutics. Here, we present the current knowledge on RND1 expression, subcellular localization, and functions in healthy tissues. Then, we review data showing that RND1 expression is dysregulated in tumors, the molecular mechanisms involved in this deregulation, and the role of RND1 in oncogenesis. For several aggressive tumors, RND1 presents the features of a tumor suppressor gene. In these tumors, low expression of RND1 is associated with a bad prognosis for the patients. Finally, we highlight that RND1 expression is induced by anticancer agents and modulates their response. Of note, RND1 mRNA levels in tumors could be used as a predictive marker of both patient prognosis and response to anticancer agents.
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Affiliation(s)
- Laetitia Mouly
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
- Faculty of Pharmacy and Medecine, Université Toulouse III, 31062 Toulouse, France
| | - Julia Gilhodes
- Institut Claudius Regaud, IUCT-O, 31059 Toulouse, France
| | - Anthony Lemarié
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
- Faculty of Pharmacy and Medecine, Université Toulouse III, 31062 Toulouse, France
| | - Elizabeth Cohen-Jonathan Moyal
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
- Faculty of Pharmacy and Medecine, Université Toulouse III, 31062 Toulouse, France
- Institut Claudius Regaud, IUCT-O, 31059 Toulouse, France
| | - Christine Toulas
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
- Institut Claudius Regaud, IUCT-O, 31059 Toulouse, France
| | - Gilles Favre
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
- Faculty of Pharmacy and Medecine, Université Toulouse III, 31062 Toulouse, France
- Institut Claudius Regaud, IUCT-O, 31059 Toulouse, France
| | - Olivier Sordet
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France
| | - Sylvie Monferran
- Cancer Research Center of Toulouse, INSERM UMR1037, 31037 Toulouse, France.
- Faculty of Pharmacy and Medecine, Université Toulouse III, 31062 Toulouse, France.
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13
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Transcriptome Response of Female Culicoides sonorensis Biting Midges (Diptera: Ceratopogonidae) to Early Infection with Epizootic Hemorrhagic Disease Virus (EHDV-2). Viruses 2019; 11:v11050473. [PMID: 31137627 PMCID: PMC6563219 DOI: 10.3390/v11050473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 12/13/2022] Open
Abstract
Female Culicoides sonorensis biting midges are vectors of epizootic hemorrhagic disease virus (EHDV), which causes morbidity and mortality in wild and domesticated ruminants. The aims in this study were to identify key changes in female midge transcriptome profiles occurring during early infection with EHDV-2. Midges were fed either negative control bloodmeals or bloodmeals containing EHDV-2 and transcriptomes were acquired at 36 h through deep sequencing. Reads were de novo assembled into a transcriptome comprised of 18,754 unigenes. Overall, there were 2401 differentially expressed unigenes and ~60% were downregulated in response to the virus (953 up; 1448 down). Downstream Gene Ontology enrichment, KEGG pathway mapping, and manual analyses were used to identify the effect of virus ingestion at both the gene and pathway levels. Downregulated unigenes were predominantly assigned to pathways related to cell/tissue structure and integrity (actin cytoskeleton, adherens junction, focal adhesion, hippo signaling), calcium signaling, eye morphogenesis and axon guidance. Unigenes attributed to sensory functions (especially vision), behavior, learning and memory were largely downregulated. Upregulated unigenes included those coding for innate immune processes, olfaction and photoreceptor pigments. Our results suggest that midges respond to virus infection as soon as 36 h post-ingestion, and that EHDV-2 may have a significant phenotypic effect on sensory and neural tissues.
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14
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Lynch-Godrei A, De Repentigny Y, Gagnon S, Trung MT, Kothary R. Dystonin-A3 upregulation is responsible for maintenance of tubulin acetylation in a less severe dystonia musculorum mouse model for hereditary sensory and autonomic neuropathy type VI. Hum Mol Genet 2019; 27:3598-3611. [PMID: 29982604 DOI: 10.1093/hmg/ddy250] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 07/02/2018] [Indexed: 12/14/2022] Open
Abstract
Hereditary sensory and autonomic neuropathy type VI (HSAN-VI) is a recessive human disease that arises from mutations in the dystonin gene (DST; also known as Bullous pemphigoid antigen 1 gene). A milder form of HSAN-VI was recently described, resulting from loss of a single dystonin isoform (DST-A2). Similarly, mutations in the mouse dystonin gene (Dst) result in severe sensory neuropathy, dystonia musculorum (Dstdt). Two Dstdt alleles, Dstdt-Tg4 and Dstdt-27J, differ in the severity of disease. The less severe Dstdt-Tg4 mice have disrupted expression of Dst-A1 and -A2 isoforms, while the more severe Dstdt-27J allele affects Dst-A1, -A2 and -A3 isoforms. As dystonin is a cytoskeletal-linker protein, we evaluated microtubule network integrity within sensory neurons from Dstdt-Tg4 and Dstdt-27J mice. There is a significant reduction in tubulin acetylation in Dstdt-27J indicative of microtubule instability and severe microtubule disorganization within sensory axons. However, Dstdt-Tg4 mice have no change in tubulin acetylation, and microtubule organization was only mildly impaired. Thus, microtubule instability is not central to initiation of Dstdt pathogenesis, though it may contribute to disease severity. Maintenance of microtubule stability in Dstdt-Tg4 dorsal root ganglia could be attributed to an upregulation in Dst-A3 expression as a compensation for the absence of Dst-A1 and -A2 in Dstdt-Tg4 sensory neurons. Indeed, knockdown of Dst-A3 in these neurons resulted in a decrease in tubulin acetylation. These findings shed light on the possible compensatory role of dystonin isoforms within HSAN-VI, which might explain the heterogeneity in symptoms within the reported forms of the disease.
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Affiliation(s)
- Anisha Lynch-Godrei
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Yves De Repentigny
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Sabrina Gagnon
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - My Tran Trung
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada.,Department of Medicine, University of Ottawa, Ottawa, Canada.,Centre for Neuromuscular Disease, University of Ottawa, Canada
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15
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Syed A, Lukacsovich T, Pomeroy M, Bardwell AJ, Decker GT, Waymire KG, Purcell J, Huang W, Gui J, Padilla EM, Park C, Paul A, Pham TBT, Rodriguez Y, Wei S, Worthge S, Zebarjedi R, Zhang B, Bardwell L, Marsh JL, MacGregor GR. Miles to go (mtgo) encodes FNDC3 proteins that interact with the chaperonin subunit CCT3 and are required for NMJ branching and growth in Drosophila. Dev Biol 2018; 445:37-53. [PMID: 30539716 DOI: 10.1016/j.ydbio.2018.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 09/01/2018] [Accepted: 10/17/2018] [Indexed: 11/17/2022]
Abstract
Analysis of mutants that affect formation and function of the Drosophila larval neuromuscular junction (NMJ) has provided valuable insight into genes required for neuronal branching and synaptic growth. We report that NMJ development in Drosophila requires both the Drosophila ortholog of FNDC3 genes; CG42389 (herein referred to as miles to go; mtgo), and CCT3, which encodes a chaperonin complex subunit. Loss of mtgo function causes late pupal lethality with most animals unable to escape the pupal case, while rare escapers exhibit an ataxic gait and reduced lifespan. NMJs in mtgo mutant larvae have dramatically reduced branching and growth and fewer synaptic boutons compared with control animals. Mutant larvae show normal locomotion but display an abnormal self-righting response and chemosensory deficits that suggest additional functions of mtgo within the nervous system. The pharate lethality in mtgo mutants can be rescued by both low-level pan- and neuronal-, but not muscle-specific expression of a mtgo transgene, supporting a neuronal-intrinsic requirement for mtgo in NMJ development. Mtgo encodes three similar proteins whose domain structure is most closely related to the vertebrate intracellular cytosolic membrane-anchored fibronectin type-III domain-containing protein 3 (FNDC3) protein family. Mtgo physically and genetically interacts with Drosophila CCT3, which encodes a subunit of the TRiC/CCT chaperonin complex required for maturation of actin, tubulin and other substrates. Drosophila larvae heterozygous for a mutation in CCT3 that reduces binding between CCT3 and MTGO also show abnormal NMJ development similar to that observed in mtgo null mutants. Hence, the intracellular FNDC3-ortholog MTGO and CCT3 can form a macromolecular complex, and are both required for NMJ development in Drosophila.
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Affiliation(s)
- Adeela Syed
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Tamás Lukacsovich
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Miles Pomeroy
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - A Jane Bardwell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Gentry Thomas Decker
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA
| | - Katrina G Waymire
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Judith Purcell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Weijian Huang
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - James Gui
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Emily M Padilla
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Cindy Park
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Antor Paul
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Thai Bin T Pham
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Yanete Rodriguez
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Stephen Wei
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Shane Worthge
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Ronak Zebarjedi
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211-7400, USA
| | - Lee Bardwell
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA
| | - J Lawrence Marsh
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA.
| | - Grant R MacGregor
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, Irvine, CA 92697-2300, USA.
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16
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Voelzmann A, Liew YT, Qu Y, Hahn I, Melero C, Sánchez-Soriano N, Prokop A. Drosophila Short stop as a paradigm for the role and regulation of spectraplakins. Semin Cell Dev Biol 2017; 69:40-57. [DOI: 10.1016/j.semcdb.2017.05.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/22/2017] [Accepted: 05/29/2017] [Indexed: 02/07/2023]
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17
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Sun W, Pei L, Liang Z. mRNA and Long Non-coding RNA Expression Profiles in Rats Reveal Inflammatory Features in Sepsis-Associated Encephalopathy. Neurochem Res 2017; 42:3199-3219. [DOI: 10.1007/s11064-017-2357-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/07/2017] [Accepted: 07/12/2017] [Indexed: 01/31/2023]
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18
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Physiological and pathophysiological functions of Swiprosin-1/EFhd2 in the nervous system. Biochem J 2017; 473:2429-37. [PMID: 27515255 DOI: 10.1042/bcj20160168] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/03/2016] [Indexed: 12/15/2022]
Abstract
Synaptic dysfunction and dysregulation of Ca(2+) are linked to neurodegenerative processes and behavioural disorders. Our understanding of the causes and factors involved in behavioural disorders and neurodegeneration, especially Alzheimer's disease (AD), a tau-related disease, is on the one hand limited and on the other hand controversial. Here, we review recent data about the links between the Ca(2+)-binding EF-hand-containing cytoskeletal protein Swiprosin-1/EFhd2 and neurodegeneration. Specifically, we summarize the functional biochemical data obtained in vitro with the use of recombinant EFhd2 protein, and integrated them with in vivo data in order to interpret the emerging role of EFhd2 in synaptic plasticity and in the pathophysiology of neurodegenerative disorders, particularly involving the tauopathies. We also discuss its functions in actin remodelling through cofilin and small GTPases, thereby linking EFhd2, synapses and the actin cytoskeleton. Expression data and functional experiments in mice and in humans have led to the hypothesis that down-regulation of EFhd2, especially in the cortex, is involved in dementia.
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19
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From Systems to Organisations. SYSTEMS 2017. [DOI: 10.3390/systems5010023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Carvajal-Gonzalez JM, Mulero-Navarro S, Smith M, Mlodzik M. A Novel Frizzled-Based Screening Tool Identifies Genetic Modifiers of Planar Cell Polarity in Drosophila Wings. G3 (BETHESDA, MD.) 2016; 6:3963-3973. [PMID: 27729438 PMCID: PMC5144966 DOI: 10.1534/g3.116.035535] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 09/24/2016] [Indexed: 01/25/2023]
Abstract
Most mutant alleles in the Fz-PCP pathway genes were discovered in classic Drosophila screens looking for recessive loss-of-function (LOF) mutations. Nonetheless, although Fz-PCP signaling is sensitive to increased doses of PCP gene products, not many screens have been performed in the wing under genetically engineered Fz overexpression conditions, mostly because the Fz phenotypes were strong and/or not easy to score and quantify. Here, we present a screen based on an unexpected mild Frizzled gain-of-function (GOF) phenotype. The leakiness of a chimeric Frizzled protein designed to be accumulated in the endoplasmic reticulum (ER) generated a reproducible Frizzled GOF phenotype in Drosophila wings. Using this genotype, we first screened a genome-wide collection of large deficiencies and found 16 strongly interacting genomic regions. Next, we narrowed down seven of those regions to finally test 116 candidate genes. We were, thus, able to identify eight new loci with a potential function in the PCP context. We further analyzed and confirmed krasavietz and its interactor short-stop as new genes acting during planar cell polarity establishment with a function related to actin and microtubule dynamics.
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Affiliation(s)
- Jose Maria Carvajal-Gonzalez
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Sonia Mulero-Navarro
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
| | - Michael Smith
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York 10029
| | - Marek Mlodzik
- Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York 10029
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York 10029
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21
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Qu Y, Hahn I, Webb SED, Pearce SP, Prokop A. Periodic actin structures in neuronal axons are required to maintain microtubules. Mol Biol Cell 2016; 28:296-308. [PMID: 27881663 PMCID: PMC5231898 DOI: 10.1091/mbc.e16-10-0727] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 11/09/2016] [Accepted: 11/15/2016] [Indexed: 12/31/2022] Open
Abstract
Drosophila genetics is combined with high-resolution microscopy and a number of functional readouts to demonstrate key factors required for the presence of regularly spaced rings of cortical actin in axons. The data suggest important roles for the actin rings in microtubule regulation, most likely by sustaining their polymerization. Axons are cable-like neuronal processes wiring the nervous system. They contain parallel bundles of microtubules as structural backbones, surrounded by regularly spaced actin rings termed the periodic membrane skeleton (PMS). Despite being an evolutionarily conserved, ubiquitous, highly ordered feature of axons, the function of PMS is unknown. Here we studied PMS abundance, organization, and function, combining versatile Drosophila genetics with superresolution microscopy and various functional readouts. Analyses with 11 actin regulators and three actin-targeting drugs suggest that PMS contains short actin filaments that are depolymerization resistant and sensitive to spectrin, adducin, and nucleator deficiency, consistent with microscopy-derived models proposing PMS as specialized cortical actin. Upon actin removal, we observed gaps in microtubule bundles, reduced microtubule polymerization, and reduced axon numbers, suggesting a role of PMS in microtubule organization. These effects become strongly enhanced when carried out in neurons lacking the microtubule-stabilizing protein Short stop (Shot). Combining the aforementioned actin manipulations with Shot deficiency revealed a close correlation between PMS abundance and microtubule regulation, consistent with a model in which PMS-dependent microtubule polymerization contributes to their maintenance in axons. We discuss potential implications of this novel PMS function along axon shafts for axon maintenance and regeneration.
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Affiliation(s)
- Yue Qu
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Ines Hahn
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Stephen E D Webb
- Rutherford Appleton Laboratory, Science and Technology Facilities Council, Didcot OX11 0QX, United Kingdom
| | - Simon P Pearce
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom.,School of Mathematics, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Andreas Prokop
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, United Kingdom
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22
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Voelzmann A, Hahn I, Pearce SP, Sánchez-Soriano N, Prokop A. A conceptual view at microtubule plus end dynamics in neuronal axons. Brain Res Bull 2016; 126:226-237. [PMID: 27530065 PMCID: PMC5090033 DOI: 10.1016/j.brainresbull.2016.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 08/08/2016] [Accepted: 08/11/2016] [Indexed: 12/02/2022]
Abstract
Axons are the cable-like protrusions of neurons which wire up the nervous system. Polar bundles of microtubules (MTs) constitute their structural backbones and are highways for life-sustaining transport between proximal cell bodies and distal synapses. Any morphogenetic changes of axons during development, plastic rearrangement, regeneration or degeneration depend on dynamic changes of these MT bundles. A key mechanism for implementing such changes is the coordinated polymerisation and depolymerisation at the plus ends of MTs within these bundles. To gain an understanding of how such regulation can be achieved at the cellular level, we provide here an integrated overview of the extensive knowledge we have about the molecular mechanisms regulating MT de/polymerisation. We first summarise insights gained from work in vitro, then describe the machinery which supplies the essential tubulin building blocks, the protein complexes associating with MT plus ends, and MT shaft-based mechanisms that influence plus end dynamics. We briefly summarise the contribution of MT plus end dynamics to important cellular functions in axons, and conclude by discussing the challenges and potential strategies of integrating the existing molecular knowledge into conceptual understanding at the level of axons.
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Affiliation(s)
- André Voelzmann
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Ines Hahn
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon P Pearce
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK; The University of Manchester, School of Mathematics, Alan Turing Building, Oxford Road, Manchester M13 9PL, UK
| | - Natalia Sánchez-Soriano
- University of Liverpool, Institute of Translational Medicine, Department of Cellular and Molecular Physiology, Crown Street, Liverpool, L69 3BX, UK
| | - Andreas Prokop
- The University of Manchester, Faculty of Biology, Medicine and Health, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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23
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Voelzmann A, Okenve-Ramos P, Qu Y, Chojnowska-Monga M, del Caño-Espinel M, Prokop A, Sanchez-Soriano N. Tau and spectraplakins promote synapse formation and maintenance through Jun kinase and neuronal trafficking. eLife 2016; 5:e14694. [PMID: 27501441 PMCID: PMC4977155 DOI: 10.7554/elife.14694] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 07/12/2016] [Indexed: 11/13/2022] Open
Abstract
The mechanisms regulating synapse numbers during development and ageing are essential for normal brain function and closely linked to brain disorders including dementias. Using Drosophila, we demonstrate roles of the microtubule-associated protein Tau in regulating synapse numbers, thus unravelling an important cellular requirement of normal Tau. In this context, we find that Tau displays a strong functional overlap with microtubule-binding spectraplakins, establishing new links between two different neurodegenerative factors. Tau and the spectraplakin Short Stop act upstream of a three-step regulatory cascade ensuring adequate delivery of synaptic proteins. This cascade involves microtubule stability as the initial trigger, JNK signalling as the central mediator, and kinesin-3 mediated axonal transport as the key effector. This cascade acts during development (synapse formation) and ageing (synapse maintenance) alike. Therefore, our findings suggest novel explanations for intellectual disability in Tau deficient individuals, as well as early synapse loss in dementias including Alzheimer's disease.
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Affiliation(s)
- Andre Voelzmann
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Pilar Okenve-Ramos
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Yue Qu
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Monika Chojnowska-Monga
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Manuela del Caño-Espinel
- Instituto de Biología y Genética Molecular-Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid-CSIC, Valladolid, Spain
| | - Andreas Prokop
- Faculty of Life Sciences, The University of Manchester, Manchester, United Kingdom
| | - Natalia Sanchez-Soriano
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
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24
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Mino RE, Rogers SL, Risinger AL, Rohena C, Banerjee S, Bhat MA. Drosophila Ringmaker regulates microtubule stabilization and axonal extension during embryonic development. J Cell Sci 2016; 129:3282-94. [PMID: 27422099 DOI: 10.1242/jcs.187294] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 07/13/2016] [Indexed: 11/20/2022] Open
Abstract
Axonal growth and targeting are fundamental to the organization of the nervous system, and require active engagement of the cytoskeleton. Polymerization and stabilization of axonal microtubules is central to axonal growth and maturation of neuronal connectivity. Studies have suggested that members of the tubulin polymerization promoting protein (TPPP, also known as P25α) family are involved in cellular process extension. However, no in vivo knockout data exists regarding its role in axonal growth during development. Here, we report the characterization of Ringmaker (Ringer; CG45057), the only Drosophila homolog of long p25α proteins. Immunohistochemical analyses indicate that Ringer expression is dynamically regulated in the embryonic central nervous system (CNS). ringer-null mutants show cell misplacement, and errors in axonal extension and targeting. Ultrastructural examination of ringer mutants revealed defective microtubule morphology and organization. Primary neuronal cultures of ringer mutants exhibit defective axonal extension, and Ringer expression in cells induced microtubule stabilization and bundling into rings. In vitro assays showed that Ringer directly affects tubulin, and promotes microtubule bundling and polymerization. Together, our studies uncover an essential function of Ringer in axonal extension and targeting through proper microtubule organization.
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Affiliation(s)
- Rosa E Mino
- Department of Physiology, University of Texas School of Medicine, Health Science Center, San Antonio, TX 78229, USA
| | - Stephen L Rogers
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - April L Risinger
- Department of Pharmacology, University of Texas School of Medicine, Health Science Center, San Antonio, TX 78229, USA
| | - Cristina Rohena
- Department of Pharmacology, University of Texas School of Medicine, Health Science Center, San Antonio, TX 78229, USA Department of Medicine, University of California, San Diego, CA 92093, USA
| | - Swati Banerjee
- Department of Physiology, University of Texas School of Medicine, Health Science Center, San Antonio, TX 78229, USA
| | - Manzoor A Bhat
- Department of Physiology, University of Texas School of Medicine, Health Science Center, San Antonio, TX 78229, USA
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Yaniv SP, Schuldiner O. A fly's view of neuronal remodeling. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:618-35. [PMID: 27351747 PMCID: PMC5086085 DOI: 10.1002/wdev.241] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/10/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
Developmental neuronal remodeling is a crucial step in sculpting the final and mature brain connectivity in both vertebrates and invertebrates. Remodeling includes degenerative events, such as neurite pruning, that may be followed by regeneration to form novel connections during normal development. Drosophila provides an excellent model to study both steps of remodeling since its nervous system undergoes massive and stereotypic remodeling during metamorphosis. Although pruning has been widely studied, our knowledge of the molecular and cellular mechanisms is far from complete. Our understanding of the processes underlying regrowth is even more fragmentary. In this review, we discuss recent progress by focusing on three groups of neurons that undergo stereotypic pruning and regrowth during metamorphosis, the mushroom body γ neurons, the dendritic arborization neurons and the crustacean cardioactive peptide peptidergic neurons. By comparing and contrasting the mechanisms involved in remodeling of these three neuronal types, we highlight the common themes and differences as well as raise key questions for future investigation in the field. WIREs Dev Biol 2016, 5:618–635. doi: 10.1002/wdev.241 For further resources related to this article, please visit the WIREs website
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Affiliation(s)
- Shiri P Yaniv
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Schuldiner
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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26
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Shamitko-Klingensmith N, W. Boyd J, Legleiter J. Microtubule modification influences cellular response to amyloid-β exposure. AIMS BIOPHYSICS 2016. [DOI: 10.3934/biophy.2016.2.261] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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27
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Dingyu W, Fanjie M, Zhengzheng D, Baosheng H, Chao Y, Yi P, Huiwen W, Jun G, Gang H. Regulation of Intracellular Structural Tension by Talin in the Axon Growth and Regeneration. Mol Neurobiol 2015; 53:4582-95. [DOI: 10.1007/s12035-015-9394-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/11/2015] [Indexed: 01/21/2023]
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Abstract
The cytoskeleton is a dynamic network of filamentous protein polymers required for virtually all cellular processes. It consists of three major classes, filamentous actin (F-actin), intermediate filaments, and microtubules, all displaying characteristic structural properties, functions, cellular distributions, and sets of interacting regulatory proteins. One unique class of proteins, the spectraplakins, bind, regulate, and integrate the functions of all three classes of cytoskeleton proteins. Spectraplakins are giant, evolutionary conserved multidomain proteins (spanning up to 9000 aa) that are true members of the plakin, spectrin, and Gas2-like protein families. They have OMIM-listed disease links to epidermolysis bullosa and hereditary sensory and autonomic neuropathy. Their role in disease is likely underrepresented since studies in model animal systems have revealed critical roles in polarity, morphogenesis, differentiation and maintenance, migration, signaling, and intracellular trafficking in a variety of tissues. This enormous diversity of spectraplakin function is consistent with the numerous isoforms produced from single genomic loci that combine different sets of functional domains in distinct cellular contexts. To study the broad range of functions and complexity of these proteins, Drosophila is a powerful model. Thus, the fly spectraplakin Short stop (Shot) acts as an actin-microtubule linker and plays important roles in many developmental processes, which provide experimentally amenable and relevant contexts in which to study spectraplakin functions. For these studies, a versatile range of relevant experimental resources that facilitate genetics and transgenic approaches, highly refined genomics tools, and an impressive set of spectraplakin-specific genetic and molecular tools are readily available. Here, we use the example of Shot to illustrate how the various tools and strategies available for Drosophila can be employed to decipher and dissect cellular roles and molecular mechanisms of spectraplakins.
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Beaven R, Dzhindzhev NS, Qu Y, Hahn I, Dajas-Bailador F, Ohkura H, Prokop A. Drosophila CLIP-190 and mammalian CLIP-170 display reduced microtubule plus end association in the nervous system. Mol Biol Cell 2015; 26:1491-508. [PMID: 25694447 PMCID: PMC4395129 DOI: 10.1091/mbc.e14-06-1083] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 02/10/2015] [Indexed: 11/11/2022] Open
Abstract
Usually, CLIPs promote microtubule growth by binding their plus ends. However, in neurons, mouse CLIP-170 and fly CLIP-190 are weak end binders, instead forming actin/myosin VI–dependent patches in the center of growth cones. Total CLIP-190 loss, even together with four other plus end binders, reveals no role in neuronal MT regulation. Axons act like cables, electrically wiring the nervous system. Polar bundles of microtubules (MTs) form their backbones and drive their growth. Plus end–tracking proteins (+TIPs) regulate MT growth dynamics and directionality at their plus ends. However, current knowledge about +TIP functions, mostly derived from work in vitro and in nonneuronal cells, may not necessarily apply to the very different context of axonal MTs. For example, the CLIP family of +TIPs are known MT polymerization promoters in nonneuronal cells. However, we show here that neither Drosophila CLIP-190 nor mammalian CLIP-170 is a prominent MT plus end tracker in neurons, which we propose is due to low plus end affinity of the CAP-Gly domain–containing N-terminus and intramolecular inhibition through the C-terminus. Instead, both CLIP-190 and CLIP-170 form F-actin–dependent patches in growth cones, mediated by binding of the coiled-coil domain to myosin-VI. Because our loss-of-function analyses in vivo and in culture failed to reveal axonal roles for CLIP-190, even in double-mutant combinations with four other +TIPs, we propose that CLIP-190 and -170 are not essential axon extension regulators. Our findings demonstrate that +TIP functions known from nonneuronal cells do not necessarily apply to the regulation of the very distinct MT networks in axons.
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Affiliation(s)
- Robin Beaven
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Nikola S Dzhindzhev
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Yue Qu
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
| | - Ines Hahn
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
| | | | - Hiroyuki Ohkura
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JR, United Kingdom
| | - Andreas Prokop
- Faculty of Life Sciences, The University of Manchester, Manchester M13 9PT, United Kingdom
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Cantera R, Ferreiro MJ, Aransay AM, Barrio R. Global gene expression shift during the transition from early neural development to late neuronal differentiation in Drosophila melanogaster. PLoS One 2014; 9:e97703. [PMID: 24830291 PMCID: PMC4022633 DOI: 10.1371/journal.pone.0097703] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 04/23/2014] [Indexed: 12/13/2022] Open
Abstract
Regulation of transcription is one of the mechanisms involved in animal development, directing changes in patterning and cell fate specification. Large temporal data series, based on microarrays across the life cycle of the fly Drosophila melanogaster, revealed the existence of groups of genes which expression increases or decreases temporally correlated during the life cycle. These groups of genes are enriched in different biological functions. Here, instead of searching for temporal coincidence in gene expression using the entire genome expression data, we searched for temporal coincidence in gene expression only within predefined catalogues of functionally related genes and investigated whether a catalogue's expression profile can be used to generate larger catalogues, enriched in genes necessary for the same function. We analyzed the expression profiles from genes already associated with early neurodevelopment and late neurodifferentiation, at embryonic stages 16 and 17 of Drosophila life cycle. We hypothesized that during this interval we would find global downregulation of genes important for early neuronal development together with global upregulation of genes necessary for the final differentiation of neurons. Our results were consistent with this hypothesis. We then investigated if the expression profile of gene catalogues representing particular processes of neural development matched the temporal sequence along which these processes occur. The profiles of genes involved in patterning, neurogenesis, axogenesis or synaptic transmission matched the prediction, with largest transcript values at the time when the corresponding biological process takes place in the embryo. Furthermore, we obtained catalogues enriched in genes involved in temporally matching functions by performing a genome-wide systematic search for genes with their highest expression levels at the corresponding embryonic intervals. These findings imply the use of gene expression data in combination with known biological information to predict the involvement of functionally uncharacterized genes in particular biological events.
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Affiliation(s)
- Rafael Cantera
- Zoology Department, Stockholm University, Stockholm, Sweden
- Developmental Neurobiology, IIBCE, Montevideo, Uruguay
- * E-mail: (RC); (RB)
| | | | | | - Rosa Barrio
- Functional Genomics, CIC bioGUNE, Derio, Spain
- * E-mail: (RC); (RB)
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Stroud MJ, Nazgiewicz A, McKenzie EA, Wang Y, Kammerer RA, Ballestrem C. GAS2-like proteins mediate communication between microtubules and actin through interactions with end-binding proteins. J Cell Sci 2014; 127:2672-82. [PMID: 24706950 PMCID: PMC4058111 DOI: 10.1242/jcs.140558] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Crosstalk between the microtubule (MT) and actin cytoskeletons is fundamental to many cellular processes including cell polarisation and cell motility. Previous work has shown that members of the growth-arrest-specific 2 (GAS2) family mediate the crosstalk between filamentous actin (F-actin) and MTs, but the molecular basis of this process remained unclear. By using fluorescence microscopy, we demonstrate that three members of this family, GAS2-like 1, GAS2-like 2 and GAS2-like 3 (G2L1, G2L2 and G2L3, also known as GAS2L1, GAS2L2 and GAS2L3, respectively) are differentially involved in mediating the crosstalk between F-actin and MTs. Although all localise to actin and MTs, only the exogenous expression of G2L1 and G2L2 influenced MT stability, dynamics and guidance along actin stress fibres. Biochemical analysis and live-cell imaging revealed that their functions are largely due to the association of these proteins with MT plus-end-binding proteins that bind to SxIP or SxLP motifs located at G2L C-termini. Our findings lead to a model in which end-binding (EB) proteins play a key role in mediating actin–MT crosstalk.
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Affiliation(s)
- Matthew J Stroud
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Alicja Nazgiewicz
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Edward A McKenzie
- Manchester Institute of Biotechnology, Faculty of Life Sciences, 131 Princess Street, Manchester M1 7DN, UK
| | - Yisu Wang
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Richard A Kammerer
- Laboratory of Biomolecular Research, OFLC 106, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland
| | - Christoph Ballestrem
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
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Roossien DH, Lamoureux P, Van Vactor D, Miller KE. Drosophila growth cones advance by forward translocation of the neuronal cytoskeletal meshwork in vivo. PLoS One 2013; 8:e80136. [PMID: 24244629 PMCID: PMC3823856 DOI: 10.1371/journal.pone.0080136] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 09/30/2013] [Indexed: 12/29/2022] Open
Abstract
In vitro studies conducted in Aplysia and chick sensory neurons indicate that in addition to microtubule assembly, long microtubules in the C-domain of the growth cone move forward as a coherent bundle during axonal elongation. Nonetheless, whether this mode of microtubule translocation contributes to growth cone motility in vivo is unknown. To address this question, we turned to the model system Drosophila. Using docked mitochondria as fiduciary markers for the translocation of long microtubules, we first examined motion along the axon to test if the pattern of axonal elongation is conserved between Drosophila and other species in vitro. When Drosophila neurons were cultured on Drosophila extracellular matrix proteins collected from the Drosophila Kc167 cell line, docked mitochondria moved in a pattern indicative of bulk microtubule translocation, similar to that observed in chick sensory neurons grown on laminin. To investigate whether the C-domain is stationary or advances in vivo, we tracked the movement of mitochondria during elongation of the aCC motor neuron in stage 16 Drosophila embryos. We found docked mitochondria moved forward along the axon shaft and in the growth cone C-domain. This work confirms that the physical mechanism of growth cone advance is similar between Drosophila and vertebrate neurons and suggests forward translocation of the microtubule meshwork in the axon underlies the advance of the growth cone C-domain in vivo. These results highlight the need for incorporating en masse microtubule translocation, in addition to assembly, into models of axonal elongation.
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Affiliation(s)
- Douglas H. Roossien
- Cell and Molecular Biology Program, Michigan State University, East Lansing, Michigan, United States of America
| | - Phillip Lamoureux
- Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America
| | - David Van Vactor
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kyle E. Miller
- Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America
- * E-mail:
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Prokop A. The intricate relationship between microtubules and their associated motor proteins during axon growth and maintenance. Neural Dev 2013; 8:17. [PMID: 24010872 PMCID: PMC3846809 DOI: 10.1186/1749-8104-8-17] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/14/2013] [Indexed: 12/15/2022] Open
Abstract
The hallmarks of neurons are their slender axons which represent the longest cellular processes of animals and which act as the cables that electrically wire the brain, and the brain to the body. Axons extend along reproducible paths during development and regeneration, and they have to be maintained for the lifetime of an organism. Both axon extension and maintenance essentially depend on the microtubule (MT) cytoskeleton. For this, MTs organize into parallel bundles that are established through extension at the leading axon tips within growth cones, and these bundles then form the architectural backbones, as well as the highways for axonal transport essential for supply and intracellular communication. Axon transport over these enormous distances takes days or even weeks and is a substantial logistical challenge. It is performed by kinesins and dynein/dynactin, which are molecular motors that form close functional links to the MTs they walk along. The intricate machinery which regulates MT dynamics, axonal transport and the motors is essential for nervous system development and function, and its investigation has huge potential to bring urgently required progress in understanding the causes of many developmental and degenerative brain disorders. During the last years new explanations for the highly specific properties of axonal MTs and for their close functional links to motor proteins have emerged, and it has become increasingly clear that motors play active roles also in regulating axonal MT networks. Here, I will provide an overview of these new developments.
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Affiliation(s)
- Andreas Prokop
- Faculty of Life Sciences, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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