1
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Saltini M, Deinum EE. Microtubule simulations in plant biology: A field coming to maturity. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102596. [PMID: 38981324 DOI: 10.1016/j.pbi.2024.102596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/24/2024] [Accepted: 06/10/2024] [Indexed: 07/11/2024]
Abstract
The plant cortical microtubule array is an important determinant of cell wall structure and, therefore, plant morphology and physiology. The array consists of dynamic microtubules interacting through frequent collisions. Since the discovery by Dixit and Cyr (2004) that the outcome of such collisions depends on the collision angle, computer simulations have been indispensable in studying array behaviour. Over the last decade, the available simulation tools have drastically improved: multiple high-quality simulation platforms exist with specific strengths and applications. Here, we review how these platforms differ on the critical aspects of microtubule nucleation, flexibility, and local orienting cues; and how such differences affect array behaviour. Building upon concepts and control parameters from theoretical models of collective microtubule behaviour, we conclude that all these factors matter in the debate about what is most important for orienting the array: local cues like mechanical stresses or global cues deriving from the cell geometry.
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Affiliation(s)
- Marco Saltini
- Mathematical & Statistical Methods (Biometris), Plant Science Group, Wageningen University, 6708 PB Wageningen, the Netherlands
| | - Eva E Deinum
- Mathematical & Statistical Methods (Biometris), Plant Science Group, Wageningen University, 6708 PB Wageningen, the Netherlands.
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2
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Coppini A, Falconieri A, Mualem O, Nasrin SR, Roudon M, Saper G, Hess H, Kakugo A, Raffa V, Shefi O. Can repetitive mechanical motion cause structural damage to axons? Front Mol Neurosci 2024; 17:1371738. [PMID: 38912175 PMCID: PMC11191579 DOI: 10.3389/fnmol.2024.1371738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/23/2024] [Indexed: 06/25/2024] Open
Abstract
Biological structures have evolved to very efficiently generate, transmit, and withstand mechanical forces. These biological examples have inspired mechanical engineers for centuries and led to the development of critical insights and concepts. However, progress in mechanical engineering also raises new questions about biological structures. The past decades have seen the increasing study of failure of engineered structures due to repetitive loading, and its origin in processes such as materials fatigue. Repetitive loading is also experienced by some neurons, for example in the peripheral nervous system. This perspective, after briefly introducing the engineering concept of mechanical fatigue, aims to discuss the potential effects based on our knowledge of cellular responses to mechanical stresses. A particular focus of our discussion are the effects of mechanical stress on axons and their cytoskeletal structures. Furthermore, we highlight the difficulty of imaging these structures and the promise of new microscopy techniques. The identification of repair mechanisms and paradigms underlying long-term stability is an exciting and emerging topic in biology as well as a potential source of inspiration for engineers.
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Affiliation(s)
| | | | - Oz Mualem
- Faculty of Engineering, Bar Ilan Institute of Nanotechnologies and Advanced Materials, Gonda Brain Research Center, Bar Ilan University, Ramat Gan, Israel
| | - Syeda Rubaiya Nasrin
- Graduate School of Science, Division of Physics and Astronomy, Kyoto University, Kyoto, Japan
| | - Marine Roudon
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Gadiel Saper
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Henry Hess
- Department of Biomedical Engineering, Columbia University, New York, NY, United States
| | - Akira Kakugo
- Graduate School of Science, Division of Physics and Astronomy, Kyoto University, Kyoto, Japan
| | | | - Orit Shefi
- Faculty of Engineering, Bar Ilan Institute of Nanotechnologies and Advanced Materials, Gonda Brain Research Center, Bar Ilan University, Ramat Gan, Israel
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3
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Hoermayer L, Montesinos JC, Trozzi N, Spona L, Yoshida S, Marhava P, Caballero-Mancebo S, Benková E, Heisenberg CP, Dagdas Y, Majda M, Friml J. Mechanical forces in plant tissue matrix orient cell divisions via microtubule stabilization. Dev Cell 2024; 59:1333-1344.e4. [PMID: 38579717 DOI: 10.1016/j.devcel.2024.03.009] [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: 04/09/2023] [Revised: 11/13/2023] [Accepted: 03/08/2024] [Indexed: 04/07/2024]
Abstract
Plant morphogenesis relies exclusively on oriented cell expansion and division. Nonetheless, the mechanism(s) determining division plane orientation remain elusive. Here, we studied tissue healing after laser-assisted wounding in roots of Arabidopsis thaliana and uncovered how mechanical forces stabilize and reorient the microtubule cytoskeleton for the orientation of cell division. We identified that root tissue functions as an interconnected cell matrix, with a radial gradient of tissue extendibility causing predictable tissue deformation after wounding. This deformation causes instant redirection of expansion in the surrounding cells and reorientation of microtubule arrays, ultimately predicting cell division orientation. Microtubules are destabilized under low tension, whereas stretching of cells, either through wounding or external aspiration, immediately induces their polymerization. The higher microtubule abundance in the stretched cell parts leads to the reorientation of microtubule arrays and, ultimately, informs cell division planes. This provides a long-sought mechanism for flexible re-arrangement of cell divisions by mechanical forces for tissue reconstruction and plant architecture.
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Affiliation(s)
- Lukas Hoermayer
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria; Department of Plant Molecular Biology (DMBV), University of Lausanne, 1015 Lausanne, Switzerland; Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Juan Carlos Montesinos
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria; Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Departamento de Bioquímica y Biología Molecular, Universitat de València, 46100 Burjassot, Spain
| | - Nicola Trozzi
- Department of Plant Molecular Biology (DMBV), University of Lausanne, 1015 Lausanne, Switzerland
| | - Leonhard Spona
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Saiko Yoshida
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria; Max Planck Institute for Plant Breeding Research, 50829 Carl-von-Linné-Weg 10, Cologne, Germany
| | - Petra Marhava
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria; Umeå Plant Science Centre (UPSC), Department of Forest Genetics and Plant Physiology, University of Agricultural Sciences (SLU), 90183 Umeå, Sweden
| | | | - Eva Benková
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | | | - Yasin Dagdas
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Mateusz Majda
- Department of Plant Molecular Biology (DMBV), University of Lausanne, 1015 Lausanne, Switzerland
| | - Jiří Friml
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria.
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4
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Halász H, Tárnai V, Matkó J, Nyitrai M, Szabó-Meleg E. Cooperation of Various Cytoskeletal Components Orchestrates Intercellular Spread of Mitochondria between B-Lymphoma Cells through Tunnelling Nanotubes. Cells 2024; 13:607. [PMID: 38607046 PMCID: PMC11011538 DOI: 10.3390/cells13070607] [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: 03/12/2024] [Accepted: 03/28/2024] [Indexed: 04/13/2024] Open
Abstract
Membrane nanotubes (NTs) are dynamic communication channels connecting spatially separated cells even over long distances and promoting the transport of different cellular cargos. NTs are also involved in the intercellular spread of different pathogens and the deterioration of some neurological disorders. Transport processes via NTs may be controlled by cytoskeletal elements. NTs are frequently observed membrane projections in numerous mammalian cell lines, including various immune cells, but their functional significance in the 'antibody factory' B cells is poorly elucidated. Here, we report that as active channels, NTs of B-lymphoma cells can mediate bidirectional mitochondrial transport, promoted by the cooperation of two different cytoskeletal motor proteins, kinesin along microtubules and myosin VI along actin, and bidirectional transport processes are also supported by the heterogeneous arrangement of the main cytoskeletal filament systems of the NTs. We revealed that despite NTs and axons being different cell extensions, the mitochondrial transport they mediate may exhibit significant similarities. Furthermore, we found that microtubules may improve the stability and lifespan of B-lymphoma-cell NTs, while F-actin strengthens NTs by providing a structural framework for them. Our results may contribute to a better understanding of the regulation of the major cells of humoral immune response to infections.
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Affiliation(s)
- Henriett Halász
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Viktória Tárnai
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - János Matkó
- Department of Immunology, Faculty of Science, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Miklós Nyitrai
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
| | - Edina Szabó-Meleg
- Department of Biophysics, Medical School, University of Pécs, H-7624 Pécs, Hungary
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5
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Falconieri A, Coppini A, Raffa V. Microtubules as a signal hub for axon growth in response to mechanical force. Biol Chem 2024; 405:67-77. [PMID: 37674311 DOI: 10.1515/hsz-2023-0173] [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: 04/04/2023] [Accepted: 08/12/2023] [Indexed: 09/08/2023]
Abstract
Microtubules are highly polar structures and are characterized by high anisotropy and stiffness. In neurons, they play a key role in the directional transport of vesicles and organelles. In the neuronal projections called axons, they form parallel bundles, mostly oriented with the plus-end towards the axonal termination. Their physico-chemical properties have recently attracted attention as a potential candidate in sensing, processing and transducing physical signals generated by mechanical forces. Here, we discuss the main evidence supporting the role of microtubules as a signal hub for axon growth in response to a traction force. Applying a tension to the axon appears to stabilize the microtubules, which, in turn, coordinate a modulation of axonal transport, local translation and their cross-talk. We speculate on the possible mechanisms modulating microtubule dynamics under tension, based on evidence collected in neuronal and non-neuronal cell types. However, the fundamental question of the causal relationship between these mechanisms is still elusive because the mechano-sensitive element in this chain has not yet been identified.
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Affiliation(s)
| | - Allegra Coppini
- Department of Biology, Università di Pisa, Pisa, 56127, Italy
| | - Vittoria Raffa
- Department of Biology, Università di Pisa, Pisa, 56127, Italy
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6
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Gudimchuk NB, Alexandrova VV. Measuring and modeling forces generated by microtubules. Biophys Rev 2023; 15:1095-1110. [PMID: 37974983 PMCID: PMC10643784 DOI: 10.1007/s12551-023-01161-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Tubulins are essential proteins, which are conserved across all eukaryotic species. They polymerize to form microtubules, cytoskeletal components of paramount importance for cellular mechanics. The microtubules combine an extraordinarily high flexural rigidity and a non-equilibrium behavior, manifested in their intermittent assembly and disassembly. These chemically fueled dynamics allow microtubules to generate significant pushing and pulling forces at their ends to reposition intracellular organelles, remodel membranes, bear compressive forces, and transport chromosomes during cell division. In this article, we review classical and recent studies, which have allowed the quantification of microtubule-generated forces. The measurements, to which we owe most of the quantitative information about microtubule forces, were carried out in biochemically reconstituted systems in vitro. We also discuss how mathematical and computational modeling has contributed to the interpretations of these results and shaped our understanding of the mechanisms of force production by tubulin polymerization and depolymerization.
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Affiliation(s)
- Nikita B. Gudimchuk
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia
- Pskov State University, Pskov, Russia
| | - Veronika V. Alexandrova
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia
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7
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Ghose A, Pullarkat P. The role of mechanics in axonal stability and development. Semin Cell Dev Biol 2023; 140:22-34. [PMID: 35786351 PMCID: PMC7615100 DOI: 10.1016/j.semcdb.2022.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/05/2022] [Accepted: 06/13/2022] [Indexed: 01/28/2023]
Abstract
Much of the focus of neuronal cell biology has been devoted to growth cone guidance, synaptogenesis, synaptic activity, plasticity, etc. The axonal shaft too has received much attention, mainly for its astounding ability to transmit action potentials and the transport of material over long distances. For these functions, the axonal cytoskeleton and membrane have been often assumed to play static structural roles. Recent experiments have changed this view by revealing an ultrastructure much richer in features than previously perceived and one that seems to be maintained at a dynamic steady state. The role of mechanics in this is only beginning to be broadly appreciated and appears to involve passive and active modes of coupling different biopolymer filaments, filament turnover dynamics and membrane biophysics. Axons, being unique cellular processes in terms of high aspect ratios and often extreme lengths, also exhibit unique passive mechanical properties that might have evolved to stabilize them under mechanical stress. In this review, we summarize the experiments that have exposed some of these features. It is our view that axonal mechanics deserves much more attention not only due to its significance in the development and maintenance of the nervous system but also due to the susceptibility of axons to injury and neurodegeneration.
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Affiliation(s)
- Aurnab Ghose
- Indian Institute of Science Education and Research, Pune 411 008, India.
| | - Pramod Pullarkat
- Raman Research Institute, C. V. Raman Avenue, Bengaluru 560 080, India.
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8
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Gcap14 is a microtubule plus-end-tracking protein coordinating microtubule-actin crosstalk during neurodevelopment. Proc Natl Acad Sci U S A 2023; 120:e2214507120. [PMID: 36795749 PMCID: PMC9974511 DOI: 10.1073/pnas.2214507120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Regulation of microtubule dynamics is required to properly control various steps of neurodevelopment. In this study, we identified granule cell antiserum-positive 14 (Gcap14) as a microtubule plus-end-tracking protein and as a regulator of microtubule dynamics during neurodevelopment. Gcap14 knockout mice exhibited impaired cortical lamination. Gcap14 deficiency resulted in defective neuronal migration. Moreover, nuclear distribution element nudE-like 1 (Ndel1), an interacting partner of Gcap14, effectively corrected the downregulation of microtubule dynamics and the defects in neuronal migration caused by Gcap14 deficiency. Finally, we found that the Gcap14-Ndel1 complex participates in the functional link between microtubule and actin filament, thereby regulating their crosstalks in the growth cones of cortical neurons. Taken together, we propose that the Gcap14-Ndel1 complex is fundamental for cytoskeletal remodeling during neurodevelopmental processes such as neuronal processes elongation and neuronal migration.
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9
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Xie P. A model for the catalytic activity of microtubule polymerases. Cytoskeleton (Hoboken) 2023; 80:7-20. [PMID: 36305831 DOI: 10.1002/cm.21734] [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: 06/13/2022] [Revised: 10/04/2022] [Accepted: 10/22/2022] [Indexed: 11/07/2022]
Abstract
A XMAP215/Stu2/Alp14 polymerase can catalyze processively the tubulin addition to the microtubule (MT) plus end. In this work, a model is proposed for the underlying molecular mechanism of the polymerase activity, where the polymerase can not only catalyze processively the tubulin addition to but also promote the tubulin removal from the MT plus end. Based on the model the dynamics of both the wild-type and mutant polymerases is studied theoretically, explaining consistently and well various available experimental data. To further test the model, predicted results are provided.
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Affiliation(s)
- Ping Xie
- Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, China
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10
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Falconieri A, De Vincentiis S, Cappello V, Convertino D, Das R, Ghignoli S, Figoli S, Luin S, Català-Castro F, Marchetti L, Borello U, Krieg M, Raffa V. Axonal plasticity in response to active forces generated through magnetic nano-pulling. Cell Rep 2022; 42:111912. [PMID: 36640304 PMCID: PMC9902337 DOI: 10.1016/j.celrep.2022.111912] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 11/16/2022] [Accepted: 12/12/2022] [Indexed: 12/30/2022] Open
Abstract
Mechanical force is crucial in guiding axon outgrowth before and after synapse formation. This process is referred to as "stretch growth." However, how neurons transduce mechanical input into signaling pathways remains poorly understood. Another open question is how stretch growth is coupled in time with the intercalated addition of new mass along the entire axon. Here, we demonstrate that active mechanical force generated by magnetic nano-pulling induces remodeling of the axonal cytoskeleton. Specifically, the increase in the axonal density of microtubules induced by nano-pulling leads to an accumulation of organelles and signaling vesicles, which, in turn, promotes local translation by increasing the probability of assembly of the "translation factories." Modulation of axonal transport and local translation sustains enhanced axon outgrowth and synapse maturation.
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Affiliation(s)
| | - Sara De Vincentiis
- Department of Biology, Università di Pisa, 56127 Pisa, Italy,The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Valentina Cappello
- Center for Materials Interfaces, Istituto Italiano di Tecnologia, 56025 Pontedera, Italy
| | - Domenica Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Ravi Das
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | | | - Sofia Figoli
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Stefano Luin
- National Enterprise for NanoScience and NanoTechnology (NEST) Laboratory, Scuola Normale Superiore, 56127 Pisa, Italy
| | - Frederic Català-Castro
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy,Department of Pharmacy, Università di Pisa, 56126 Pisa, Italy
| | - Ugo Borello
- Department of Biology, Università di Pisa, 56127 Pisa, Italy
| | - Michael Krieg
- The Barcelona Institute of Science and Technology, Institut de Ciències Fotòniques, ICFO, 08860 Castelldefels, Spain
| | - Vittoria Raffa
- Department of Biology, Università di Pisa, 56127 Pisa, Italy.
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11
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Kuo YW, Mahamdeh M, Tuna Y, Howard J. The force required to remove tubulin from the microtubule lattice by pulling on its α-tubulin C-terminal tail. Nat Commun 2022; 13:3651. [PMID: 35752623 PMCID: PMC9233703 DOI: 10.1038/s41467-022-31069-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 06/01/2022] [Indexed: 11/18/2022] Open
Abstract
Severing enzymes and molecular motors extract tubulin from the walls of microtubules by exerting mechanical force on subunits buried in the lattice. However, how much force is needed to remove tubulin from microtubules is not known, nor is the pathway by which subunits are removed. Using a site-specific functionalization method, we applied forces to the C-terminus of α-tubulin with an optical tweezer and found that a force of ~30 pN is required to extract tubulin from the microtubule wall. Additionally, we discovered that partial unfolding is an intermediate step in tubulin removal. The unfolding and extraction forces are similar to those generated by AAA-unfoldases. Lastly, we show that three kinesin-1 motor proteins can also extract tubulin from the microtubule lattice. Our results provide the first experimental investigation of how tubulin responds to mechanical forces exerted on its α-tubulin C-terminal tail and have implications for the mechanisms of severing enzymes and microtubule stability. Tubulin, the building blocks of microtubules, can be removed from the microtubule wall by mechanical forces. Using single-molecule methods, the authors show that tubulin partially unfolds prior to its removal and determined the tubulin-extraction force.
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Affiliation(s)
- Yin-Wei Kuo
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Mohammed Mahamdeh
- Harvard Medical School, Boston, MA, USA.,Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA, USA
| | - Yazgan Tuna
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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12
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Hornak I, Rieger H. Stochastic model of T Cell repolarization during target elimination (II). Biophys J 2022; 121:1246-1265. [PMID: 35196513 PMCID: PMC9034251 DOI: 10.1016/j.bpj.2022.02.029] [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: 06/28/2021] [Revised: 08/08/2021] [Accepted: 02/16/2022] [Indexed: 11/16/2022] Open
Abstract
Cytotoxic T lymphocytes (T cells) and natural killer cells form a tight contact, the immunological synapse (IS), with target cells, where they release their lytic granules containing perforin/granzyme and cytokine-containing vesicles. During this process the cell repolarizes and moves the microtubule organizing center (MTOC) toward the IS. In the first part of our work we developed a computational model for the molecular-motor-driven motion of the microtubule cytoskeleton during T cell polarization and analyzed the effects of cortical-sliding and capture-shrinkage mechanisms. Here we use this model to analyze the dynamics of the MTOC repositioning in situations in which 1) the IS is in an arbitrary position with respect to the initial position of the MTOC and 2) the T cell has two IS at two arbitrary positions. In the case of one IS, we found that the initial position determines which mechanism is dominant and that the time of repositioning does not rise monotonously with the MTOC-IS distance. In the case of two IS, we observe several scenarios that have also been reported experimentally: the MTOC alternates stochastically (but with a well-defined average transition time) between the two IS; it wiggles in between the two IS without transiting to one of the two; or it is at some point pulled to one of the two IS and stays there. Our model allows one to predict which scenario emerges in dependency of the mechanisms in action and the number of dyneins present. We report that the presence of capture-shrinkage mechanism in at least one IS is necessary to assure the transitions in every cell configuration. Moreover, the frequency of transitions does not decrease with the distance between the two IS and is the highest when both mechanisms are present in both IS.
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Affiliation(s)
- Ivan Hornak
- Department of Theoretical Physics, Center for Biophysics, Saarland University, Saarbrücken, Germany.
| | - Heiko Rieger
- Department of Theoretical Physics, Center for Biophysics, Saarland University, Saarbrücken, Germany
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13
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Halat LS, Bali B, Wasteneys G. Cytoplasmic Linker Protein-Associating Protein at the Nexus of Hormone Signaling, Microtubule Organization, and the Transition From Division to Differentiation in Primary Roots. FRONTIERS IN PLANT SCIENCE 2022; 13:883363. [PMID: 35574108 PMCID: PMC9096829 DOI: 10.3389/fpls.2022.883363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 04/07/2022] [Indexed: 05/13/2023]
Abstract
The transition from cell division to differentiation in primary roots is dependent on precise gradients of phytohormones, including auxin, cytokinins and brassinosteroids. The reorganization of microtubules also plays a key role in determining whether a cell will enter another round of mitosis or begin to rapidly elongate as the first step in terminal differentiation. In the last few years, progress has been made to establish connections between signaling pathways at distinct locations within the root. This review focuses on the different factors that influence whether a root cell remains in the division zone or transitions to elongation and differentiation using Arabidopsis thaliana as a model system. We highlight the role of the microtubule-associated protein CLASP as an intermediary between sustaining hormone signaling and controlling microtubule organization. We discuss new, innovative tools and methods, such as hormone sensors and computer modeling, that are allowing researchers to more accurately visualize the belowground growth dynamics of plants.
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14
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Malivert A, Erguvan Ö, Chevallier A, Dehem A, Friaud R, Liu M, Martin M, Peyraud T, Hamant O, Verger S. FERONIA and microtubules independently contribute to mechanical integrity in the Arabidopsis shoot. PLoS Biol 2021; 19:e3001454. [PMID: 34767544 PMCID: PMC8612563 DOI: 10.1371/journal.pbio.3001454] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 11/24/2021] [Accepted: 10/22/2021] [Indexed: 11/19/2022] Open
Abstract
To survive, cells must constantly resist mechanical stress. In plants, this involves the reinforcement of cell walls, notably through microtubule-dependent cellulose deposition. How wall sensing might contribute to this response is unknown. Here, we tested whether the microtubule response to stress acts downstream of known wall sensors. Using a multistep screen with 11 mutant lines, we identify FERONIA (FER) as the primary candidate for the cell’s response to stress in the shoot. However, this does not imply that FER acts upstream of the microtubule response to stress. In fact, when performing mechanical perturbations, we instead show that the expected microtubule response to stress does not require FER. We reveal that the feronia phenotype can be partially rescued by reducing tensile stress levels. Conversely, in the absence of both microtubules and FER, cells appear to swell and burst. Altogether, this shows that the microtubule response to stress acts as an independent pathway to resist stress, in parallel to FER. We propose that both pathways are required to maintain the mechanical integrity of plant cells. In all living organisms, cells must resist mechanical stress to survive. This study of the model plant Arabidopsis reveals that the candidate cell wall mechanoreceptor FERONIA and microtubules independently contribute to this mechanical feedback.
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Affiliation(s)
- Alice Malivert
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Özer Erguvan
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Antoine Chevallier
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Antoine Dehem
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Rodrigue Friaud
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Mengying Liu
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Marjolaine Martin
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Théophile Peyraud
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
| | - Olivier Hamant
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
- * E-mail: (OH); (SV)
| | - Stéphane Verger
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, UCB Lyon 1, ENS de Lyon, INRAE, CNRS, Lyon, France
- * E-mail: (OH); (SV)
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15
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Regulation of microtubule dynamics, mechanics and function through the growing tip. Nat Rev Mol Cell Biol 2021; 22:777-795. [PMID: 34408299 DOI: 10.1038/s41580-021-00399-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2021] [Indexed: 02/07/2023]
Abstract
Microtubule dynamics and their control are essential for the normal function and division of all eukaryotic cells. This plethora of functions is, in large part, supported by dynamic microtubule tips, which can bind to various intracellular targets, generate mechanical forces and couple with actin microfilaments. Here, we review progress in the understanding of microtubule assembly and dynamics, focusing on new information about the structure of microtubule tips. First, we discuss evidence for the widely accepted GTP cap model of microtubule dynamics. Next, we address microtubule dynamic instability in the context of structural information about assembly intermediates at microtubule tips. Three currently discussed models of microtubule assembly and dynamics are reviewed. These are considered in the context of established facts and recent data, which suggest that some long-held views must be re-evaluated. Finally, we review structural observations about the tips of microtubules in cells and describe their implications for understanding the mechanisms of microtubule regulation by associated proteins, by mechanical forces and by microtubule-targeting drugs, prominently including cancer chemotherapeutics.
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16
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External Mechanical Cues Reveal a Katanin-Independent Mechanism behind Auxin-Mediated Tissue Bending in Plants. Dev Cell 2021; 56:67-80.e3. [PMID: 33434527 DOI: 10.1016/j.devcel.2020.12.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 10/29/2020] [Accepted: 12/10/2020] [Indexed: 11/21/2022]
Abstract
Tissue folding is a central building block of plant and animal morphogenesis. In dicotyledonous plants, hypocotyl folds to form hooks after seedling germination that protects their aerial stem cell niche during emergence from soil. Auxin response factors and auxin transport are reported to play a key role in this process. Here, we show that the microtubule-severing enzyme katanin contributes to hook formation. However, by exposing hypocotyls to external mechanical cues mimicking the natural soil environment, we reveal that auxin response factors ARF7/ARF19, auxin influx carriers, and katanin are dispensable for apical hook formation, indicating that these factors primarily play the role of catalyzers of tissue bending in the absence of external mechanical cues. Instead, our results reveal the key roles of the non-canonical TMK-mediated auxin pathway, PIN efflux carriers, and cellulose microfibrils as components of the core pathway behind hook formation in the presence or absence of external mechanical cues.
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17
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McIntosh JR. Anaphase A. Semin Cell Dev Biol 2021; 117:118-126. [PMID: 33781672 DOI: 10.1016/j.semcdb.2021.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
Anaphase A is the motion of recently separated chromosomes to the spindle pole they face. It is accompanied by the shortening of kinetochore-attached microtubules. The requisite tubulin depolymerization may occur at kinetochores, at poles, or both, depending on the species and/or the time in mitosis. These depolymerization events are local and suggest that cells regulate microtubule dynamics in specific places, presumably by the localization of relevant enzymes and microtubule-associated proteins to specific loci, such as pericentriolar material and outer kinetochores. Motor enzymes can contribute to anaphase A, both by altering microtubule stability and by pushing or pulling microtubules through the cell. The generation of force on chromosomes requires couplings that can both withstand the considerable force that spindles can generate and simultaneously permit tubulin addition and loss. This chapter reviews literature on the molecules that regulate anaphase microtubule dynamics, couple dynamic microtubules to kinetochores and poles, and generate forces for microtubule and chromosome motion.
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Affiliation(s)
- J Richard McIntosh
- Dept. of Molecular, Cellular, and Developmental Biology University of Colorado, Boulder, CO 80309-0347, USA.
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18
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Shake It Off: The Elimination of Erroneous Kinetochore-Microtubule Attachments and Chromosome Oscillation. Int J Mol Sci 2021; 22:ijms22063174. [PMID: 33804687 PMCID: PMC8003821 DOI: 10.3390/ijms22063174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/18/2021] [Indexed: 01/17/2023] Open
Abstract
Cell proliferation and sexual reproduction require the faithful segregation of chromosomes. Chromosome segregation is driven by the interaction of chromosomes with the spindle, and the attachment of chromosomes to the proper spindle poles is essential. Initial attachments are frequently erroneous due to the random nature of the attachment process; however, erroneous attachments are selectively eliminated. Proper attachment generates greater tension at the kinetochore than erroneous attachments, and it is thought that attachment selection is dependent on this tension. However, studies of meiotic chromosome segregation suggest that attachment elimination cannot be solely attributed to tension, and the precise mechanism of selective elimination of erroneous attachments remains unclear. During attachment elimination, chromosomes oscillate between the spindle poles. A recent study on meiotic chromosome segregation in fission yeast has suggested that attachment elimination is coupled to chromosome oscillation. In this review, the possible contribution of chromosome oscillation in the elimination of erroneous attachment is discussed in light of the recent finding.
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19
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Wakiya M, Nishi E, Kawai S, Yamada K, Katsumata K, Hirayasu A, Itabashi Y, Yamamoto A. Chiasmata and the kinetochore component Dam1 are crucial for elimination of erroneous chromosome attachments and centromere oscillation at meiosis I. Open Biol 2021; 11:200308. [PMID: 33529549 PMCID: PMC8061696 DOI: 10.1098/rsob.200308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Establishment of proper chromosome attachments to the spindle requires elimination of erroneous attachments, but the mechanism of this process is not fully understood. During meiosis I, sister chromatids attach to the same spindle pole (mono-oriented attachment), whereas homologous chromosomes attach to opposite poles (bi-oriented attachment), resulting in homologous chromosome segregation. Here, we show that chiasmata that link homologous chromosomes and kinetochore component Dam1 are crucial for elimination of erroneous attachments and oscillation of centromeres between the spindle poles at meiosis I in fission yeast. In chiasma-forming cells, Mad2 and Aurora B kinase, which provides time for attachment correction and destabilizes erroneous attachments, respectively, caused elimination of bi-oriented attachments of sister chromatids, whereas in chiasma-lacking cells, they caused elimination of mono-oriented attachments. In chiasma-forming cells, in addition, homologous centromere oscillation was coordinated. Furthermore, Dam1 contributed to attachment elimination in both chiasma-forming and chiasma-lacking cells, and drove centromere oscillation. These results demonstrate that chiasmata alter attachment correction patterns by enabling error correction factors to eliminate bi-oriented attachment of sister chromatids, and suggest that Dam1 induces elimination of erroneous attachments. The coincidental contribution of chiasmata and Dam1 to centromere oscillation also suggests a potential link between centromere oscillation and attachment elimination.
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Affiliation(s)
- Misuzu Wakiya
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Eriko Nishi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Shinnosuke Kawai
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kazuhiro Katsumata
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ami Hirayasu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan.,Department of Chemistry, Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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20
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Trinh DC, Alonso-Serra J, Asaoka M, Colin L, Cortes M, Malivert A, Takatani S, Zhao F, Traas J, Trehin C, Hamant O. How Mechanical Forces Shape Plant Organs. Curr Biol 2021; 31:R143-R159. [PMID: 33561417 DOI: 10.1016/j.cub.2020.12.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Plants produce organs of various shapes and sizes. While much has been learned about genetic regulation of organogenesis, the integration of mechanics in the process is also gaining attention. Here, we consider the role of forces as instructive signals in organ morphogenesis. Turgor pressure is the primary cause of mechanical signals in developing organs. Because plant cells are glued to each other, mechanical signals act, in essence, at multiple scales, through cell wall contiguity and water flux. In turn, cells use such signals to resist mechanical stress, for instance, by reinforcing their cell walls. We show that the three elemental shapes behind plant organs - spheres, cylinders and lamina - can be actively maintained by such a mechanical feedback. Combinations of this 3-letter alphabet can generate more complex shapes. Furthermore, mechanical conflicts emerge at the boundary between domains exhibiting different growth rates or directions. These secondary mechanical signals contribute to three other organ shape features - folds, shape reproducibility and growth arrest. The further integration of mechanical signals with the molecular network offers many fruitful prospects for the scientific community, including the role of proprioception in organ shape robustness or the definition of cell and organ identities as a result of an interplay between biochemical and mechanical signals.
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Affiliation(s)
- Duy-Chi Trinh
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France; Department of Pharmacological, Medical and Agronomical Biotechnology, University of Science and Technology of Hanoi, Cau Giay District, Hanoi, Vietnam
| | - Juan Alonso-Serra
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Mariko Asaoka
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Leia Colin
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Matthieu Cortes
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Alice Malivert
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Shogo Takatani
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Feng Zhao
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Jan Traas
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Christophe Trehin
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Olivier Hamant
- Laboratoire de Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCBL, INRAE, CNRS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
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21
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Microtubules pull the strings: disordered sequences as efficient couplers of microtubule-generated force. Essays Biochem 2020; 64:371-382. [PMID: 32502246 DOI: 10.1042/ebc20190078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/01/2020] [Accepted: 05/14/2020] [Indexed: 11/17/2022]
Abstract
Microtubules are dynamic polymers that grow and shrink through addition or loss of tubulin subunits at their ends. Microtubule ends generate mechanical force that moves chromosomes and cellular organelles, and provides mechanical tension. Recent literature describes a number of proteins and protein complexes that couple dynamics of microtubule ends to movements of their cellular cargoes. These 'couplers' are quite diverse in their microtubule-binding domains (MTBDs), while sharing similarity in function, but a systematic understanding of the principles underlying their activity is missing. Here, I review various types of microtubule couplers, focusing on their essential activities: ability to follow microtubule ends and capture microtubule-generated force. Most of the couplers require presence of unstructured positively charged sequences and multivalency in their microtubule-binding sites to efficiently convert the microtubule-generated force into useful connection to a cargo. An overview of the microtubule features supporting end-tracking and force-coupling, and the experimental methods to assess force-coupling properties is also provided.
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22
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Gudimchuk NB, Ulyanov EV, O'Toole E, Page CL, Vinogradov DS, Morgan G, Li G, Moore JK, Szczesna E, Roll-Mecak A, Ataullakhanov FI, Richard McIntosh J. Mechanisms of microtubule dynamics and force generation examined with computational modeling and electron cryotomography. Nat Commun 2020; 11:3765. [PMID: 32724196 PMCID: PMC7387542 DOI: 10.1038/s41467-020-17553-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/08/2020] [Indexed: 01/15/2023] Open
Abstract
Microtubules are dynamic tubulin polymers responsible for many cellular processes, including the capture and segregation of chromosomes during mitosis. In contrast to textbook models of tubulin self-assembly, we have recently demonstrated that microtubules elongate by addition of bent guanosine triphosphate tubulin to the tips of curving protofilaments. Here we explore this mechanism of microtubule growth using Brownian dynamics modeling and electron cryotomography. The previously described flaring shapes of growing microtubule tips are remarkably consistent under various assembly conditions, including different tubulin concentrations, the presence or absence of a polymerization catalyst or tubulin-binding drugs. Simulations indicate that development of substantial forces during microtubule growth and shortening requires a high activation energy barrier in lateral tubulin-tubulin interactions. Modeling offers a mechanism to explain kinetochore coupling to growing microtubule tips under assisting force, and it predicts a load-dependent acceleration of microtubule assembly, providing a role for the flared morphology of growing microtubule ends.
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Affiliation(s)
- Nikita B Gudimchuk
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia.
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia.
- Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia.
| | - Evgeni V Ulyanov
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
| | - Eileen O'Toole
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Cynthia L Page
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Dmitrii S Vinogradov
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia
| | - Garry Morgan
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Gabriella Li
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ewa Szczesna
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
| | - Fazoil I Ataullakhanov
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, Moscow, Russia
- Dmitry Rogachev National Research Center of Pediatric Hematology, Oncology and Immunology, Moscow, Russia
| | - J Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
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23
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Extremely Low Forces Induce Extreme Axon Growth. J Neurosci 2020; 40:4997-5007. [PMID: 32444384 DOI: 10.1523/jneurosci.3075-19.2020] [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: 12/31/2019] [Revised: 04/16/2020] [Accepted: 04/21/2020] [Indexed: 12/27/2022] Open
Abstract
Stretch-growth has been defined as a process that extends axons via the application of mechanical forces. In the present article, we used a protocol based on magnetic nanoparticles (NPs) for labeling the entire axon tract of hippocampal neurons, and an external magnetic field gradient to generate a dragging force. We found that the application of forces below 10 pN induces growth at a rate of 0.66 ± 0.02 µm h-1 pN-1 Calcium imaging confirmed the strong increase in elongation rate, in comparison with the condition of tip-growth. Enhanced growth in stretched axons was also accompanied by endoplasmic reticulum (ER) accumulation and, accordingly, it was blocked by an inhibition of translation. Stretch-growth was also found to stimulate axonal branching, glutamatergic synaptic transmission, and neuronal excitability. Moreover, stretched axons showed increased microtubule (MT) density and MT assembly was key to sustaining stretch-growth, suggesting a possible role of tensile forces in MT translocation/assembly. Additionally, our data showed that stretched axons do not respond to BDNF signaling, suggesting interference between the two pathways. As these extremely low mechanical forces are physiologically relevant, stretch-growth could be an important endogenous mechanism of axon growth, with a potential for designing novel strategies for axonal regrowth.SIGNIFICANCE STATEMENT Axon growth involves motion, and motion is driven by forces. The growth cone (GC) itself can generate very low intracellular forces by inducing a drastic cytoskeleton remodeling, in response to signaling molecules. Here, we investigated the key role of intracellular force as an endogenous regulator of axon outgrowth, which it has been neglected for decades because of the lack of methodologies to investigate the topic. Our results indicate a critical role of force in promoting axon growth by facilitating microtubule (MT) polymerization.
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24
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Abstract
Mechanical signals play many roles in cell and developmental biology. Several mechanotransduction pathways have been uncovered, but the mechanisms identified so far only address the perception of stress intensity. Mechanical stresses are tensorial in nature, and thus provide dual mechanical information: stress magnitude and direction. Here we propose a parsimonious mechanism for the perception of the principal stress direction. In vitro experiments show that microtubules are stabilized under tension. Based on these results, we explore the possibility that such microtubule stabilization operates in vivo, most notably in plant cells where turgor-driven tensile stresses exceed greatly those observed in animal cells. Cellular mechanical stress is a key determinant of cell shape and function, but how the cell senses stress direction is unclear. In this Perspective the authors propose that microtubules autonomously sense stress directions in plant cells, where tensile stresses are higher than in animal cells.
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25
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Abstract
Microtubules are dynamic polymers of αβ-tubulin that are essential for intracellular organization, organelle trafficking and chromosome segregation. Microtubule growth and shrinkage occur via addition and loss of αβ-tubulin subunits, which are biochemical processes. Dynamic microtubules can also engage in mechanical processes, such as exerting forces by pushing or pulling against a load. Recent advances at the intersection of biochemistry and mechanics have revealed the existence of multiple conformations of αβ-tubulin subunits and their central role in dictating the mechanisms of microtubule dynamics and force generation. It has become apparent that microtubule-associated proteins (MAPs) selectively target specific tubulin conformations to regulate microtubule dynamics, and mechanical forces can also influence microtubule dynamics by altering the balance of tubulin conformations. Importantly, the conformational states of tubulin dimers are likely to be coupled throughout the lattice: the conformation of one dimer can influence the conformation of its nearest neighbours, and this effect can propagate over longer distances. This coupling provides a long-range mechanism by which MAPs and forces can modulate microtubule growth and shrinkage. These findings provide evidence that the interplay between biochemistry and mechanics is essential for the cellular functions of microtubules.
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Affiliation(s)
- Gary J Brouhard
- Department of Biology, McGill University, Montréal, Quebec, Canada.
| | - Luke M Rice
- Department of Biophysics, University of Texas Southwestern, Dallas, TX, USA.
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26
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Kanfer G, Peterka M, Arzhanik VK, Drobyshev AL, Ataullakhanov FI, Volkov VA, Kornmann B. CENP-F couples cargo to growing and shortening microtubule ends. Mol Biol Cell 2017; 28:2400-2409. [PMID: 28701340 PMCID: PMC5576903 DOI: 10.1091/mbc.e16-11-0756] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 06/20/2017] [Accepted: 06/27/2017] [Indexed: 12/03/2022] Open
Abstract
Unlike canonical transport, in which cargo is attached to molecular motors, CENP-F promotes the transport of cargoes such as mitochondria by directly attaching them to the tips of growing and shrinking microtubules. Dynamic microtubule ends exert pulling and pushing forces on intracellular membranes and organelles. However, the mechanical linkage of microtubule tips to their cargoes is poorly understood. CENP-F is a nonmotor microtubule-binding protein that participates in microtubule binding at kinetochores and in the mitotic redistribution of the mitochondrial network. CENP-F–driven mitochondrial transport is linked to growing microtubule tips, but the underlying molecular mechanisms are unknown. Here we show that CENP-F tracks growing microtubule ends in living cells. In vitro reconstitution demonstrates that microtubule tips can transport mitochondria and CENP-F–coated artificial cargoes over micrometer-long distances during both growing and shrinking phases. Based on these and previous observations, we suggest that CENP-F might act as a transporter of mitochondria and other cellular cargoes by attaching them to dynamic microtubule ends during both polymerization and depolymerization of tubulin.
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Affiliation(s)
- Gil Kanfer
- Institute of Biochemistry, ETH Zurich, ZH 8093 Zurich, Switzerland
| | - Martin Peterka
- Institute of Biochemistry, ETH Zurich, ZH 8093 Zurich, Switzerland
| | - Vladimir K Arzhanik
- Department of Bioengineering and Bioinformatics, Moscow State University, 119991 Moscow, Russia
| | - Alexei L Drobyshev
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Fazly I Ataullakhanov
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Vladimir A Volkov
- Center for Theoretical Problems of Physicochemical Pharmacology, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Benoît Kornmann
- Institute of Biochemistry, ETH Zurich, ZH 8093 Zurich, Switzerland
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27
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Tamrin SH, Majedi FS, Tondar M, Sanati-Nezhad A, Hasani-Sadrabadi MM. Electromagnetic Fields and Stem Cell Fate: When Physics Meets Biology. Rev Physiol Biochem Pharmacol 2017; 171:63-97. [PMID: 27515674 DOI: 10.1007/112_2016_4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Controlling stem cell (SC) fate is an extremely important topic in the realm of SC research. A variety of different external cues mainly mechanical, chemical, or electrical stimulations individually or in combination have been incorporated to control SC fate. Here, we will deconstruct the probable relationship between the functioning of electromagnetic (EMF) and SC fate of a variety of different SCs. The electromagnetic (EM) nature of the cells is discussed with the emphasis on the effects of EMF on the determinant factors that directly and/or indirectly influence cell fate. Based on the EM effects on a variety of cellular processes, it is believed that EMFs can be engineered to provide a controlled signal with the highest impact on the SC fate decision. Considering the novelty and broad applications of applying EMFs to change SC fate, it is necessary to shed light on many unclear mechanisms underlying this phenomenon.
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Affiliation(s)
- Sara Hassanpour Tamrin
- Center of Excellence in Biomaterials, Department of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | | | - Mahdi Tondar
- Department of Biochemistry and Molecular & Cellular Biology, School of Medicine, Georgetown University, Washington, DC, USA
| | - Amir Sanati-Nezhad
- BioMEMS and BioInspired Microfluidic Laboratory, Department of Mechanical and Manufacturing Engineering, Center for Bioengineering Research and Education, University of Calgary, Calgary, AB, Canada, T2N1N4.
| | - Mohammad Mahdi Hasani-Sadrabadi
- Department of Chemistry & Biochemistry, and California NanoSystems Institute, University of California at Los Angeles, Los Angeles, CA, 90095, USA.
- Parker H. Petit Institute for Bioengineering and Bioscience and G.W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
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28
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Asbury CL. Anaphase A: Disassembling Microtubules Move Chromosomes toward Spindle Poles. BIOLOGY 2017; 6:E15. [PMID: 28218660 PMCID: PMC5372008 DOI: 10.3390/biology6010015] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 02/04/2017] [Accepted: 02/10/2017] [Indexed: 11/16/2022]
Abstract
The separation of sister chromatids during anaphase is the culmination of mitosis and one of the most strikingly beautiful examples of cellular movement. It consists of two distinct processes: Anaphase A, the movement of chromosomes toward spindle poles via shortening of the connecting fibers, and anaphase B, separation of the two poles from one another via spindle elongation. I focus here on anaphase A chromosome-to-pole movement. The chapter begins by summarizing classical observations of chromosome movements, which support the current understanding of anaphase mechanisms. Live cell fluorescence microscopy studies showed that poleward chromosome movement is associated with disassembly of the kinetochore-attached microtubule fibers that link chromosomes to poles. Microtubule-marking techniques established that kinetochore-fiber disassembly often occurs through loss of tubulin subunits from the kinetochore-attached plus ends. In addition, kinetochore-fiber disassembly in many cells occurs partly through 'flux', where the microtubules flow continuously toward the poles and tubulin subunits are lost from minus ends. Molecular mechanistic models for how load-bearing attachments are maintained to disassembling microtubule ends, and how the forces are generated to drive these disassembly-coupled movements, are discussed.
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Affiliation(s)
- Charles L Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA.
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Grishchuk EL. Biophysics of Microtubule End Coupling at the Kinetochore. PROGRESS IN MOLECULAR AND SUBCELLULAR BIOLOGY 2017; 56:397-428. [PMID: 28840247 DOI: 10.1007/978-3-319-58592-5_17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The main physiological function of mitotic kinetochores is to provide durable attachment to spindle microtubules, which segregate chromosomes in order to partition them equally between the two daughter cells. Numerous kinetochore components that can bind directly to microtubules have been identified, including ATP-dependent motors and various microtubule-associated proteins with no motor activity. A major challenge facing the field is to explain chromosome motions based on the biochemical and structural properties of these individual kinetochore components and their assemblies. This chapter reviews the molecular mechanisms responsible for the motions associated with dynamic microtubule tips at the single-molecule level, as well as the activities of multimolecular ensembles called couplers. These couplers enable persistent kinetochore motion even under load, but their exact composition and structure remain unknown. Because no natural or artificial macro-machines function in an analogous manner to these molecular nano-devices, understanding their underlying biophysical mechanisms will require conceptual advances.
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Affiliation(s)
- Ekaterina L Grishchuk
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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30
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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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31
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Shaebani MR, Pasula A, Ott A, Santen L. Tracking of plus-ends reveals microtubule functional diversity in different cell types. Sci Rep 2016; 6:30285. [PMID: 27461361 PMCID: PMC4962100 DOI: 10.1038/srep30285] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/29/2016] [Indexed: 11/09/2022] Open
Abstract
Many cellular processes are tightly connected to the dynamics of microtubules (MTs). While in neuronal axons MTs mainly regulate intracellular trafficking, they participate in cytoskeleton reorganization in many other eukaryotic cells, enabling the cell to efficiently adapt to changes in the environment. We show that the functional differences of MTs in different cell types and regions is reflected in the dynamic properties of MT tips. Using plus-end tracking proteins EB1 to monitor growing MT plus-ends, we show that MT dynamics and life cycle in axons of human neurons significantly differ from that of fibroblast cells. The density of plus-ends, as well as the rescue and catastrophe frequencies increase while the growth rate decreases toward the fibroblast cell margin. This results in a rather stable filamentous network structure and maintains the connection between nucleus and membrane. In contrast, plus-ends are uniformly distributed along the axons and exhibit diverse polymerization run times and spatially homogeneous rescue and catastrophe frequencies, leading to MT segments of various lengths. The probability distributions of the excursion length of polymerization and the MT length both follow nearly exponential tails, in agreement with the analytical predictions of a two-state model of MT dynamics.
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Affiliation(s)
- M Reza Shaebani
- Department of Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany
| | - Aravind Pasula
- Department of Experimental Physics, Saarland University, 66041 Saarbrücken, Germany
| | - Albrecht Ott
- Department of Experimental Physics, Saarland University, 66041 Saarbrücken, Germany
| | - Ludger Santen
- Department of Theoretical Physics, Saarland University, 66041 Saarbrücken, Germany
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32
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Miller MP, Asbury CL, Biggins S. A TOG Protein Confers Tension Sensitivity to Kinetochore-Microtubule Attachments. Cell 2016; 165:1428-1439. [PMID: 27156448 DOI: 10.1016/j.cell.2016.04.030] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/25/2016] [Accepted: 04/07/2016] [Indexed: 01/10/2023]
Abstract
The development and survival of all organisms depends on equal partitioning of their genomes during cell division. Accurate chromosome segregation requires selective stabilization of kinetochore-microtubule attachments that come under tension due to opposing pulling forces exerted on sister kinetochores by dynamic microtubule tips. Here, we show that the XMAP215 family member, Stu2, makes a major contribution to kinetochore-microtubule coupling. Stu2 and its human ortholog, ch-TOG, exhibit a conserved interaction with the Ndc80 kinetochore complex that strengthens its attachment to microtubule tips. Strikingly, Stu2 can either stabilize or destabilize kinetochore attachments, depending on the level of kinetochore tension and whether the microtubule tip is assembling or disassembling. These dichotomous effects of Stu2 are independent of its previously studied regulation of microtubule dynamics. Altogether, our results demonstrate how a kinetochore-associated factor can confer opposing, tension-dependent effects to selectively stabilize tension-bearing attachments, providing mechanistic insight into the basis for accuracy during chromosome segregation.
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Affiliation(s)
- Matthew P Miller
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Charles L Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, USA.
| | - Sue Biggins
- Howard Hughes Medical Institute, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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33
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Bugiel M, Böhl E, Schäffer E. The Kinesin-8 Kip3 switches protofilaments in a sideward random walk asymmetrically biased by force. Biophys J 2016; 108:2019-27. [PMID: 25902441 DOI: 10.1016/j.bpj.2015.03.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 02/12/2015] [Accepted: 03/10/2015] [Indexed: 12/19/2022] Open
Abstract
Molecular motors translocate along cytoskeletal filaments, as in the case of kinesin motors on microtubules. Although conventional kinesin-1 tracks a single microtubule protofilament, other kinesins, akin to dyneins, switch protofilaments. However, the molecular trajectory-whether protofilament switching occurs in a directed or stochastic manner-is unclear. Here, we used high-resolution optical tweezers to track the path of single budding yeast kinesin-8, Kip3, motor proteins. Under applied sideward loads, we found that individual motors stepped sideward in both directions, with and against loads, with a broad distribution in measured step sizes. Interestingly, the force response depended on the direction. Based on a statistical analysis and simulations accounting for the geometry, we propose a diffusive sideward stepping motion of Kip3 on the microtubule lattice, asymmetrically biased by force. This finding is consistent with previous multimotor gliding assays and sheds light on the molecular switching mechanism. For kinesin-8, the diffusive switching mechanism may enable the motor to bypass obstacles and reach the microtubule end for length regulation. For other motors, such a mechanism may have implications for torque generation around the filament axis.
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Affiliation(s)
- Michael Bugiel
- Cellular Nanoscience Group, Center for Plant Molecular Biology, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Elisa Böhl
- Cellular Nanoscience Group, Center for Plant Molecular Biology, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Erik Schäffer
- Cellular Nanoscience Group, Center for Plant Molecular Biology, Eberhard Karls Universität Tübingen, Tübingen, Germany.
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Berger O, Adler-Abramovich L, Levy-Sakin M, Grunwald A, Liebes-Peer Y, Bachar M, Buzhansky L, Mossou E, Forsyth VT, Schwartz T, Ebenstein Y, Frolow F, Shimon LJW, Patolsky F, Gazit E. Light-emitting self-assembled peptide nucleic acids exhibit both stacking interactions and Watson-Crick base pairing. NATURE NANOTECHNOLOGY 2015; 10:353-360. [PMID: 25775151 DOI: 10.1038/nnano.2015.27] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 02/02/2015] [Indexed: 06/04/2023]
Abstract
The two main branches of bionanotechnology involve the self-assembly of either peptides or DNA. Peptide scaffolds offer chemical versatility, architectural flexibility and structural complexity, but they lack the precise base pairing and molecular recognition available with nucleic acid assemblies. Here, inspired by the ability of aromatic dipeptides to form ordered nanostructures with unique physical properties, we explore the assembly of peptide nucleic acids (PNAs), which are short DNA mimics that have an amide backbone. All 16 combinations of the very short di-PNA building blocks were synthesized and assayed for their ability to self-associate. Only three guanine-containing di-PNAs-CG, GC and GG-could form ordered assemblies, as observed by electron microscopy, and these di-PNAs efficiently assembled into discrete architectures within a few minutes. The X-ray crystal structure of the GC di-PNA showed the occurrence of both stacking interactions and Watson-Crick base pairing. The assemblies were also found to exhibit optical properties including voltage-dependent electroluminescence and wide-range excitation-dependent fluorescence in the visible region.
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Affiliation(s)
- Or Berger
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Lihi Adler-Abramovich
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Michal Levy-Sakin
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Assaf Grunwald
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Yael Liebes-Peer
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Mor Bachar
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Ludmila Buzhansky
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Estelle Mossou
- 1] Partnership for Structural Biology, Institut Laue Langevin, 71 Avenue des Martyrs, Grenoble Cedex 9 38042, France [2] Faculty of Natural Sciences, Keele University, Staffordshire ST5 5BG, UK
| | - V Trevor Forsyth
- 1] Partnership for Structural Biology, Institut Laue Langevin, 71 Avenue des Martyrs, Grenoble Cedex 9 38042, France [2] Faculty of Natural Sciences, Keele University, Staffordshire ST5 5BG, UK
| | - Tal Schwartz
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Yuval Ebenstein
- School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Felix Frolow
- 1] Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel [2] Daniella Rich Institute for Structural Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Linda J W Shimon
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Fernando Patolsky
- 1] School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Ramat Aviv 69978, Israel [2] Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978, Israel
| | - Ehud Gazit
- 1] Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel [2] Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978, Israel
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Sampathkumar A, Krupinski P, Wightman R, Milani P, Berquand A, Boudaoud A, Hamant O, Jönsson H, Meyerowitz EM. Subcellular and supracellular mechanical stress prescribes cytoskeleton behavior in Arabidopsis cotyledon pavement cells. eLife 2014; 3:e01967. [PMID: 24740969 PMCID: PMC3985187 DOI: 10.7554/elife.01967] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although it is a central question in biology, how cell shape controls intracellular dynamics largely remains an open question. Here, we show that the shape of Arabidopsis pavement cells creates a stress pattern that controls microtubule orientation, which then guides cell wall reinforcement. Live-imaging, combined with modeling of cell mechanics, shows that microtubules align along the maximal tensile stress direction within the cells, and atomic force microscopy demonstrates that this leads to reinforcement of the cell wall parallel to the microtubules. This feedback loop is regulated: cell-shape derived stresses could be overridden by imposed tissue level stresses, showing how competition between subcellular and supracellular cues control microtubule behavior. Furthermore, at the microtubule level, we identified an amplification mechanism in which mechanical stress promotes the microtubule response to stress by increasing severing activity. These multiscale feedbacks likely contribute to the robustness of microtubule behavior in plant epidermis. DOI:http://dx.doi.org/10.7554/eLife.01967.001 The surfaces of plants are covered in epithelial cells that come in many different shapes, suggesting that individual cells must have some control over their own shape. An unusually shaped epithelial cell is the pavement cell, which looks like a jigsaw puzzle piece and is found in the leaves of many flowering plants. Relatively little was known about the exact contribution of mechanical properties of the wall to this shape. Furthermore, although it was known that parts of pavement cells are rich in microtubules—tubes of protein that act as a scaffold inside the cell— the possibility that shape impacts the behavior of microtubules was not fully addressed. Now, using a combination of computer modelling and experiments, Sampathkumar et al. reveal that the shape of the pavement cells relies in part on the response of the microtubules to stress. In an individual cell, microtubules align along the direction of the largest stress, with a protein severing those microtubules that are not aligned in this direction. As the stress inside a cell is determined in part by the cell’s shape, this sets up a feedback loop: the stress resulting from the cell shape aligns the microtubules that reinforce the cell wall, thus maintaining the shape of the cell. An external stress applied to the epithelium can override this internal stress. Because all of the plant cells are under turgor pressure from the inside, pressure from the outside, like squeezing a balloon, changes the stress pattern, causing the realignment of the microtubules so as to resist the new stress. This shows that the microtubules respond to local stresses within a cell, and are continually responsive to stress changes. DOI:http://dx.doi.org/10.7554/eLife.01967.002
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Affiliation(s)
- Arun Sampathkumar
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
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36
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Louveaux M, Hamant O. The mechanics behind cell division. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:774-9. [PMID: 24211120 DOI: 10.1016/j.pbi.2013.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/07/2013] [Accepted: 10/17/2013] [Indexed: 05/24/2023]
Abstract
It is now well established that the orientation of the plane of cell division highly depends on cell geometry in plants. However, the related molecular mechanism remains largely unknown. Recent data in animal systems highlight the role of the cytoskeleton response to mechanical stress in this process. Interestingly, these results are consistent with some data obtained in parallel in plants. Here we review and confront these studies, across kingdoms, and we explore the possibility that the intrinsic mechanical properties of the cytoskeleton play a key role in the nexus between cell division and mechanical stress. This opens many avenues for future research that are also discussed in this review.
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Affiliation(s)
- Marion Louveaux
- Laboratoire de Reproduction et Developpement des Plantes, INRA, CNRS, ENS, UCB Lyon 1, 46 Allee d'Italie, Lyon Cedex 07 69364, France; Laboratoire Joliot Curie, CNRS, ENS Lyon, Universite de Lyon, 46 Allee d'Italie, Lyon Cedex 07 69364, France
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Cell division: control of the chromosomal passenger complex in time and space. Chromosoma 2013; 123:25-42. [PMID: 24091645 PMCID: PMC3967068 DOI: 10.1007/s00412-013-0437-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/19/2013] [Accepted: 09/20/2013] [Indexed: 12/11/2022]
Abstract
The ultimate goal of cell division is equal transmission of the duplicated genome to two new daughter cells. Multiple surveillance systems exist that monitor proper execution of the cell division program and as such ensure stability of our genome. One widely studied protein complex essential for proper chromosome segregation and execution of cytoplasmic division (cytokinesis) is the chromosomal passenger complex (CPC). This highly conserved complex consists of Borealin, Survivin, INCENP, and Aurora B kinase, and has a dynamic localization pattern during mitosis and cytokinesis. Not surprisingly, it also performs various functions during these phases of the cell cycle. In this review, we will give an overview of the latest insights into the regulation of CPC localization and discuss if and how specific localization impacts its diverse functions in the dividing cell.
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