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Hargreaves D, Woolner S, Jensen OE. Relaxation and Noise-Driven Oscillations in a Model of Mitotic Spindle Dynamics. Bull Math Biol 2024; 86:113. [PMID: 39096399 PMCID: PMC11297845 DOI: 10.1007/s11538-024-01341-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 07/11/2024] [Indexed: 08/05/2024]
Abstract
During cell division, the mitotic spindle moves dynamically through the cell to position the chromosomes and determine the ultimate spatial position of the two daughter cells. These movements have been attributed to the action of cortical force generators which pull on the astral microtubules to position the spindle, as well as pushing events by these same microtubules against the cell cortex and plasma membrane. Attachment and detachment of cortical force generators working antagonistically against centring forces of microtubules have been modelled previously (Grill et al. in Phys Rev Lett 94:108104, 2005) via stochastic simulations and mean-field Fokker-Planck equations (describing random motion of force generators) to predict oscillations of a spindle pole in one spatial dimension. Using systematic asymptotic methods, we reduce the Fokker-Planck system to a set of ordinary differential equations (ODEs), consistent with a set proposed by Grill et al., which can provide accurate predictions of the conditions for the Fokker-Planck system to exhibit oscillations. In the limit of small restoring forces, we derive an algebraic prediction of the amplitude of spindle-pole oscillations and demonstrate the relaxation structure of nonlinear oscillations. We also show how noise-induced oscillations can arise in stochastic simulations for conditions in which the mean-field Fokker-Planck system predicts stability, but for which the period can be estimated directly by the ODE model and the amplitude by a related stochastic differential equation that incorporates random binding kinetics.
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Affiliation(s)
- Dionn Hargreaves
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
| | - Sarah Woolner
- Faculty of Biology, Medicine and Health, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
| | - Oliver E Jensen
- Department of Mathematics, University of Manchester, Oxford Road, Manchester, M13 9PL, UK
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2
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de-Carvalho J, Tlili S, Saunders TE, Telley IA. The positioning mechanics of microtubule asters in Drosophila embryo explants. eLife 2024; 12:RP90541. [PMID: 38426416 PMCID: PMC10911390 DOI: 10.7554/elife.90541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
Microtubule asters are essential in localizing the action of microtubules in processes including mitosis and organelle positioning. In large cells, such as the one-cell sea urchin embryo, aster dynamics are dominated by hydrodynamic pulling forces. However, in systems with more densely positioned nuclei such as the early Drosophila embryo, which packs around 6000 nuclei within the syncytium in a crystalline-like order, it is unclear what processes dominate aster dynamics. Here, we take advantage of a cell cycle regulation Drosophila mutant to generate embryos with multiple asters, independent from nuclei. We use an ex vivo assay to further simplify this biological system to explore the forces generated by and between asters. Through live imaging, drug and optical perturbations, and theoretical modeling, we demonstrate that these asters likely generate an effective pushing force over short distances.
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Affiliation(s)
- Jorge de-Carvalho
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
| | - Sham Tlili
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
| | - Timothy E Saunders
- Mechanobiology Institute and Department of Biological Sciences, National University of SingaporeSingaporeSingapore
- Institute of Molecular and Cellular Biology, A*Star, ProteosSingaporeSingapore
- Centre for Mechanochemical Cell Biology, Warwick Medical School, University of WarwickWarwickUnited Kingdom
| | - Ivo A Telley
- Instituto Gulbenkian de Ciência, Fundação Calouste GulbenkianOeirasPortugal
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3
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Sen A, Chowdhury D, Kunwar A. Coordination, cooperation, competition, crowding and congestion of molecular motors: Theoretical models and computer simulations. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 141:563-650. [PMID: 38960486 DOI: 10.1016/bs.apcsb.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Cytoskeletal motor proteins are biological nanomachines that convert chemical energy into mechanical work to carry out various functions such as cell division, cell motility, cargo transport, muscle contraction, beating of cilia and flagella, and ciliogenesis. Most of these processes are driven by the collective operation of several motors in the crowded viscous intracellular environment. Imaging and manipulation of the motors with powerful experimental probes have been complemented by mathematical analysis and computer simulations of the corresponding theoretical models. In this article, we illustrate some of the key theoretical approaches used to understand how coordination, cooperation and competition of multiple motors in the crowded intra-cellular environment drive the processes that are essential for biological function of a cell. In spite of the focus on theory, experimentalists will also find this article as an useful summary of the progress made so far in understanding multiple motor systems.
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Affiliation(s)
- Aritra Sen
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
| | - Debashish Chowdhury
- Department of Physics, Indian Institute of Technology Kanpur, Kanpur, Uttar Pradesh, India
| | - Ambarish Kunwar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.
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4
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Saleh J, Fardin MA, Barai A, Soleilhac M, Frenoy O, Gaston C, Cui H, Dang T, Gaudin N, Vincent A, Minc N, Delacour D. Length limitation of astral microtubules orients cell divisions in murine intestinal crypts. Dev Cell 2023; 58:1519-1533.e6. [PMID: 37419117 DOI: 10.1016/j.devcel.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 05/25/2023] [Accepted: 06/14/2023] [Indexed: 07/09/2023]
Abstract
Planar spindle orientation is critical for epithelial tissue organization and is generally instructed by the long cell-shape axis or cortical polarity domains. We introduced mouse intestinal organoids in order to study spindle orientation in a monolayered mammalian epithelium. Although spindles were planar, mitotic cells remained elongated along the apico-basal (A-B) axis, and polarity complexes were segregated to basal poles, so that spindles oriented in an unconventional manner, orthogonal to both polarity and geometric cues. Using high-resolution 3D imaging, simulations, and cell-shape and cytoskeleton manipulations, we show that planar divisions resulted from a length limitation in astral microtubules (MTs) which precludes them from interacting with basal polarity, and orient spindles from the local geometry of apical domains. Accordingly, lengthening MTs affected spindle planarity, cell positioning, and crypt arrangement. We conclude that MT length regulation may serve as a key mechanism for spindles to sense local cell shapes and tissue forces to preserve mammalian epithelial architecture.
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Affiliation(s)
- Jad Saleh
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | | | - Amlan Barai
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Matis Soleilhac
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Olivia Frenoy
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Cécile Gaston
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Hongyue Cui
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Tien Dang
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Noémie Gaudin
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France
| | - Audrey Vincent
- Université de Lille, CNRS, INSERM, CHU Lille, UMR9020-U1277, 59000 Lille, France; ORGALille Core Facility, CANTHER, Université de Lille, CNRS, INSERM, CHU Lille, UMR9020-U1277, 59000 Lille, France
| | - Nicolas Minc
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France; Equipe Labellisée La Ligue Contre le Cancer, France.
| | - Delphine Delacour
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France.
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5
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Yang S, Au FK, Li G, Lin J, Li XD, Qi RZ. Autoinhibitory mechanism controls binding of centrosomin motif 1 to γ-tubulin ring complex. J Cell Biol 2023; 222:e202007101. [PMID: 37213089 PMCID: PMC10202828 DOI: 10.1083/jcb.202007101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/03/2023] [Accepted: 03/24/2023] [Indexed: 05/23/2023] Open
Abstract
The γ-tubulin ring complex (γTuRC) is the principal nucleator of cellular microtubules, and the microtubule-nucleating activity of the complex is stimulated by binding to the γTuRC-mediated nucleation activator (γTuNA) motif. The γTuNA is part of the centrosomin motif 1 (CM1), which is widely found in γTuRC stimulators, including CDK5RAP2. Here, we show that a conserved segment within CM1 binds to the γTuNA and blocks its association with γTuRCs; therefore, we refer to this segment as the γTuNA inhibitor (γTuNA-In). Mutational disruption of the interaction between the γTuNA and the γTuNA-In results in a loss of autoinhibition, which consequently augments microtubule nucleation on centrosomes and the Golgi complex, the two major microtubule-organizing centers. This also causes centrosome repositioning, leads to defects in Golgi assembly and organization, and affects cell polarization. Remarkably, phosphorylation of the γTuNA-In, probably by Nek2, counteracts the autoinhibition by disrupting the γTuNA‒γTuNA-In interaction. Together, our data reveal an on-site mechanism for controlling γTuNA function.
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Affiliation(s)
- Shaozhong Yang
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Franco K.C. Au
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Gefei Li
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jianwei Lin
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Xiang David Li
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Robert Z. Qi
- Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
- Bioscience and Biomedical Engineering Thrust, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou, China
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6
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Som S, Paul R. Mechanistic model for nuclear migration in hyphae during mitosis. Phys Rev E 2023; 108:014401. [PMID: 37583222 DOI: 10.1103/physreve.108.014401] [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: 03/02/2023] [Accepted: 06/13/2023] [Indexed: 08/17/2023]
Abstract
Saccharomyces cerevisiae and Candida albicans, the two well-known human pathogens, can be found in all three morphologies, i.e., yeast, pseudohyphae, and true hyphae. The cylindrical daughter-bud (germ tube) grows very long for true hyphae, and the cell cycle is delayed compared to the other two morphologies. The place of the nuclear division is specific for true hyphae determined by the position of the septin ring. However, the septin ring can localize anywhere inside the germ tube, unlike the mother-bud junction in budding yeast. Since the nucleus often migrates a long path in the hyphae, the underlying mechanism must be robust for executing mitosis in a timely manner. We explore the mechanism of nuclear migration through hyphae in light of mechanical interactions between astral microtubules and the cell cortex. We report that proper migration through constricted hyphae requires a large dynein pull applied on the astral microtubules from the hyphal cortex. This is achieved when the microtubules frequently slide along the hyphal cortex so that a large population of dyneins actively participate, pulling on them. Simulation shows timely migration when the dyneins from the mother cortex do not participate in pulling on the microtubules. These findings are robust for long migration and positioning of the nucleus in the germ tube at the septin ring.
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Affiliation(s)
- Subhendu Som
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Raja Paul
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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7
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Carmona B, Marinho HS, Matos CL, Nolasco S, Soares H. Tubulin Post-Translational Modifications: The Elusive Roles of Acetylation. BIOLOGY 2023; 12:biology12040561. [PMID: 37106761 PMCID: PMC10136095 DOI: 10.3390/biology12040561] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/27/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023]
Abstract
Microtubules (MTs), dynamic polymers of α/β-tubulin heterodimers found in all eukaryotes, are involved in cytoplasm spatial organization, intracellular transport, cell polarity, migration and division, and in cilia biology. MTs functional diversity depends on the differential expression of distinct tubulin isotypes and is amplified by a vast number of different post-translational modifications (PTMs). The addition/removal of PTMs to α- or β-tubulins is catalyzed by specific enzymes and allows combinatory patterns largely enriching the distinct biochemical and biophysical properties of MTs, creating a code read by distinct proteins, including microtubule-associated proteins (MAPs), which allow cellular responses. This review is focused on tubulin-acetylation, whose cellular roles continue to generate debate. We travel through the experimental data pointing to α-tubulin Lys40 acetylation role as being a MT stabilizer and a typical PTM of long lived MTs, to the most recent data, suggesting that Lys40 acetylation enhances MT flexibility and alters the mechanical properties of MTs, preventing MTs from mechanical aging characterized by structural damage. Additionally, we discuss the regulation of tubulin acetyltransferases/desacetylases and their impacts on cell physiology. Finally, we analyze how changes in MT acetylation levels have been found to be a general response to stress and how they are associated with several human pathologies.
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Affiliation(s)
- Bruno Carmona
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
| | - H Susana Marinho
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Catarina Lopes Matos
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Sofia Nolasco
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Helena Soares
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
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8
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Yamamoto S, Gaillard J, Vianay B, Guerin C, Orhant-Prioux M, Blanchoin L, Théry M. Actin network architecture can ensure robust centering or sensitive decentering of the centrosome. EMBO J 2022; 41:e111631. [PMID: 35916262 PMCID: PMC9574749 DOI: 10.15252/embj.2022111631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/24/2022] [Accepted: 07/06/2022] [Indexed: 01/17/2023] Open
Abstract
The orientation of cell polarity depends on the position of the centrosome, the main microtubule-organizing center (MTOC). Microtubules (MTs) transmit pushing forces to the MTOC as they grow against the cell periphery. How the actin network regulates these forces remains unclear. Here, in a cell-free assay, we used purified proteins to reconstitute the interaction of a microtubule aster with actin networks of various architectures in cell-sized microwells. In the absence of actin filaments, MTOC positioning was highly sensitive to variations in microtubule length. The presence of a bulk actin network limited microtubule displacement, and MTOCs were held in place. In contrast, the assembly of a branched actin network along the well edges centered the MTOCs by maintaining an isotropic balance of pushing forces. An anisotropic peripheral actin network caused the MTOC to decenter by focusing the pushing forces. Overall, our results show that actin networks can limit the sensitivity of MTOC positioning to microtubule length and enforce robust MTOC centering or decentering depending on the isotropy of its architecture.
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Affiliation(s)
- Shohei Yamamoto
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Jérémie Gaillard
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Benoit Vianay
- Institut de Recherche Saint Louis, UMRS1160-HIPI, CytoMorpho Lab, University of Paris, CEA, INSERM, Paris, France
| | - Christophe Guerin
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Magali Orhant-Prioux
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Laurent Blanchoin
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.,Institut de Recherche Saint Louis, UMRS1160-HIPI, CytoMorpho Lab, University of Paris, CEA, INSERM, Paris, France
| | - Manuel Théry
- Interdisciplinary Research Institute of Grenoble, UMR5168-LPCV, CytoMorpho Lab, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.,Institut de Recherche Saint Louis, UMRS1160-HIPI, CytoMorpho Lab, University of Paris, CEA, INSERM, Paris, France
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9
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Willantarra I, Leung S, Choi YS, Chhana A, McGlashan SR. Chondrocyte-specific response to stiffness-mediated primary cilia formation and centriole positioning. Am J Physiol Cell Physiol 2022; 323:C236-C247. [PMID: 35649254 DOI: 10.1152/ajpcell.00135.2022] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mechanical stress and the stiffness of the extracellular matrix are key drivers of tissue development and homeostasis. Aberrant mechanosensation is associated with a wide range of pathologies, including osteoarthritis. Matrix (or substrate) stiffness plays a major role in cell spreading, adhesion, proliferation and differentiation. However, how specific cells sense substrate stiffness still remains unclude. The primary cilium is an essential cellular organelle that senses and integrates mechanical and chemical signals from the extracellular environment. We hypothesised that the primary cilium dynamically alters its length and position to fine-tune cell mechanosignalling based on substrate stiffness alone. We used a hydrogel system of varying substrate stiffness to examine the role of stiffness on cilia frequency, length and centriole position as well as cell and nuclei area over time. Contrary to other cell types, we show that chondrocyte primary cilia shorten on softer substrates demonstrating tissue-specific mechanosensing which is aligned with the tissue stiffness the cells originate from. We further show that stiffness determines centriole positioning to either the basal or apical membrane during attachment and spreading, with centriole positioned towards the basal membrane on stiffer substrates. These phenomena are mediated by force generation actin-myosin stress fibres in a time-dependent manner. Finally we show on stiff substrates, that primary cilia are involved in tension-mediated cell spreading. We propose that substrate stiffness plays a role in cilia positioning, regulating cellular responses to external forces, and may be a key driver of mechanosignalling-associated diseases.
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Affiliation(s)
- Ivanna Willantarra
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Sophia Leung
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Yu Suk Choi
- School of Human Sciences, University of Western Australia, Perth, Australia
| | - Ashika Chhana
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Sue R McGlashan
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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10
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Sai X, Ikawa Y, Nishimura H, Mizuno K, Kajikawa E, Katoh TA, Kimura T, Shiratori H, Takaoka K, Hamada H, Minegishi K. Planar cell polarity-dependent asymmetric organization of microtubules for polarized positioning of the basal body in node cells. Development 2022; 149:275058. [PMID: 35420656 DOI: 10.1242/dev.200315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 03/30/2022] [Indexed: 12/31/2022]
Abstract
For left-right symmetry breaking in the mouse embryo, the basal body must become positioned at the posterior side of node cells, but the precise mechanism for this has remained unknown. Here, we examined the role of microtubules (MTs) and actomyosin in this basal body positioning. Exposure of mouse embryos to agents that stabilize or destabilize MTs or F-actin impaired such positioning. Active myosin II was detected at the anterior side of node cells before the posterior shift of the basal body, and this asymmetric activation was lost in Prickle and dachsous mutant embryos. The organization of basal-body associated MTs (baMTs) was asymmetric between the anterior and posterior sides of node cells, with anterior baMTs extending horizontally and posterior baMTs extending vertically. This asymmetry became evident after polarization of the PCP core protein Vangl1 and before the posterior positioning of the basal body, and it also required the PCP core proteins Prickle and dachsous. Our results suggest that the asymmetry in baMT organization may play a role in correct positioning of the basal body for left-right symmetry breaking.
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Affiliation(s)
- Xiaorei Sai
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Yayoi Ikawa
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
| | - Hiromi Nishimura
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
| | - Katsutoshi Mizuno
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Eriko Kajikawa
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Takanobu A Katoh
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Toshiya Kimura
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan
| | - Hidetaka Shiratori
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
| | - Katsuyoshi Takaoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
| | - Hiroshi Hamada
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
| | - Katsura Minegishi
- Laboratory for Organismal Patterning, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo 650-0047, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 560-0011, Japan
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11
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Khetan N, Pruliere G, Hebras C, Chenevert J, Athale CA. Self-organized optimal packing of kinesin-5-driven microtubule asters scales with cell size. J Cell Sci 2021; 134:jcs257543. [PMID: 34080632 DOI: 10.1242/jcs.257543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 04/18/2021] [Indexed: 12/18/2022] Open
Abstract
Radial microtubule (MT) arrays or asters determine cell geometry in animal cells. Multiple asters interacting with motors, such as those in syncytia, form intracellular patterns, but the mechanical principles behind this are not clear. Here, we report that oocytes of the marine ascidian Phallusia mammillata treated with the drug BI-D1870 spontaneously form cytoplasmic MT asters, or cytasters. These asters form steady state segregation patterns in a shell just under the membrane. Cytaster centers tessellate the oocyte cytoplasm, that is divide it into polygonal structures, dominated by hexagons, in a kinesin-5-dependent manner, while inter-aster MTs form 'mini-spindles'. A computational model of multiple asters interacting with kinesin-5 can reproduce both tessellation patterns and mini-spindles in a manner specific to the number of MTs per aster, MT lengths and kinesin-5 density. Simulations predict that the hexagonal tessellation patterns scale with increasing cell size, when the packing fraction of asters in cells is ∼1.6. This self-organized in vivo tessellation by cytasters is comparable to the 'circle packing problem', suggesting that there is an intrinsic mechanical pattern-forming module that is potentially relevant to understanding the role of collective mechanics of cytoskeletal elements in embryogenesis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Neha Khetan
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Gérard Pruliere
- LBDV, Sorbonne Universite/CNRS, 06230 Villefranche-sur-Mer, France
| | - Celine Hebras
- LBDV, Sorbonne Universite/CNRS, 06230 Villefranche-sur-Mer, France
| | - Janet Chenevert
- LBDV, Sorbonne Universite/CNRS, 06230 Villefranche-sur-Mer, France
| | - Chaitanya A Athale
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
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12
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Bouvrais H, Chesneau L, Le Cunff Y, Fairbrass D, Soler N, Pastezeur S, Pécot T, Kervrann C, Pécréaux J. The coordination of spindle-positioning forces during the asymmetric division of the Caenorhabditis elegans zygote. EMBO Rep 2021; 22:e50770. [PMID: 33900015 DOI: 10.15252/embr.202050770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 12/28/2022] Open
Abstract
In Caenorhabditis elegans zygote, astral microtubules generate forces essential to position the mitotic spindle, by pushing against and pulling from the cortex. Measuring microtubule dynamics there, we revealed the presence of two populations, corresponding to pulling and pushing events. It offers a unique opportunity to study, under physiological conditions, the variations of both spindle-positioning forces along space and time. We propose a threefold control of pulling force, by polarity, spindle position and mitotic progression. We showed that the sole anteroposterior asymmetry in dynein on-rate, encoding pulling force imbalance, is sufficient to cause posterior spindle displacement. The positional regulation, reflecting the number of microtubule contacts in the posterior-most region, reinforces this imbalance only in late anaphase. Furthermore, we exhibited the first direct proof that dynein processivity increases along mitosis. It reflects the temporal control of pulling forces, which strengthens at anaphase onset following mitotic progression and independently from chromatid separation. In contrast, the pushing force remains constant and symmetric and contributes to maintaining the spindle at the cell centre during metaphase.
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Affiliation(s)
| | | | - Yann Le Cunff
- CNRS, IGDR - UMR 6290, University of Rennes, Rennes, France
| | | | - Nina Soler
- CNRS, IGDR - UMR 6290, University of Rennes, Rennes, France
| | | | - Thierry Pécot
- INRIA, Centre Rennes - Bretagne Atlantique, Rennes, France
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13
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Gavriljuk K, Scocozza B, Ghasemalizadeh F, Seidel H, Nandan AP, Campos-Medina M, Schmick M, Koseska A, Bastiaens PIH. A self-organized synthetic morphogenic liposome responds with shape changes to local light cues. Nat Commun 2021; 12:1548. [PMID: 33750780 PMCID: PMC7943604 DOI: 10.1038/s41467-021-21679-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/29/2021] [Indexed: 12/02/2022] Open
Abstract
Reconstituting artificial proto-cells capable of transducing extracellular signals into cytoskeletal changes can reveal fundamental principles of how non-equilibrium phenomena in cellular signal transduction affect morphogenesis. Here, we generated a Synthetic Morphogenic Membrane System (SynMMS) by encapsulating a dynamic microtubule (MT) aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. Responding to light cues in analogy to morphogens, this biomimetic design embodies basic principles of localized Rho-GTPase signal transduction that generate an intracellular MT-regulator signaling gradient. Light-induced signaling promotes membrane-deforming growth of MT-filaments by dynamically elevating the membrane-proximal tubulin concentration. The resulting membrane deformations enable recursive coupling of the MT-aster with the signaling system, which generates global self-organized morphologies that reorganize towards local external cues in dependence on prior shape. SynMMS thereby signifies a step towards bio-inspired engineering of self-organized cellular morphogenesis. The authors generated a Synthetic Morphogenic Membrane System by encapsulating a dynamic microtubule aster and a light-inducible signaling system driven by GTP/ATP chemical potential into cell-sized liposomes. This reconstitution of artificial proto-cells reveals how non-equilibrium phenomena affect cellular information processing in morphogenesis.
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Affiliation(s)
- Konstantin Gavriljuk
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Bruno Scocozza
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Farid Ghasemalizadeh
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Hans Seidel
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Akhilesh P Nandan
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany.,Cellular Computations and Learning, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Manuel Campos-Medina
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Malte Schmick
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Aneta Koseska
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany.,Cellular Computations and Learning, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Philippe I H Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany. .,Faculty of Chemistry and Chemical Biology, TU Dortmund, Dortmund, Germany.
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14
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Jimenez AJ, Schaeffer A, De Pascalis C, Letort G, Vianay B, Bornens M, Piel M, Blanchoin L, Théry M. Acto-myosin network geometry defines centrosome position. Curr Biol 2021; 31:1206-1220.e5. [DOI: 10.1016/j.cub.2021.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 11/20/2020] [Accepted: 01/04/2021] [Indexed: 10/22/2022]
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15
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Sulerud T, Sami AB, Li G, Kloxin A, Oakey J, Gatlin J. Microtubule-dependent pushing forces contribute to long-distance aster movement and centration in Xenopus laevis egg extracts. Mol Biol Cell 2020; 31:2791-2802. [PMID: 33026931 PMCID: PMC7851858 DOI: 10.1091/mbc.e20-01-0088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During interphase of the eukaryotic cell cycle, the microtubule (MT) cytoskeleton serves as both a supportive scaffold for organelles and an arborized system of tracks for intracellular transport. At the onset of mitosis, the position of the astral MT network, specifically its center, determines the eventual location of the spindle apparatus and ultimately the cytokinetic furrow. Positioning of the MT aster often results in its movement to the center of a cell, even in large blastomeres hundreds of microns in diameter. This translocation requires positioning forces, yet how these forces are generated and then integrated within cells of various sizes and geometries remains an open question. Here we describe a method that combines microfluidics, hydrogels, and Xenopus laevis egg extract to investigate the mechanics of aster movement and centration. We determined that asters were able to find the center of artificial channels and annular cylinders, even when cytoplasmic dynein-dependent pulling mechanisms were inhibited. Characterization of aster movement away from V-shaped hydrogel barriers provided additional evidence for a MT-based pushing mechanism. Importantly, the distance over which this mechanism seemed to operate was longer than that predicted by radial aster growth models, agreeing with recent models of a more complex MT network architecture within the aster.
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Affiliation(s)
- Taylor Sulerud
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Cell Organization and Division Group, Marine Biological Laboratory, Woods Hole, MA 02543
| | | | - Guihe Li
- Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071
| | - April Kloxin
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716
| | - John Oakey
- Department of Chemical Engineering, University of Wyoming, Laramie, WY 82071.,Cell Organization and Division Group, Marine Biological Laboratory, Woods Hole, MA 02543
| | - Jesse Gatlin
- Department of Molecular Biology, University of Wyoming, Laramie, WY 82071.,Cell Organization and Division Group, Marine Biological Laboratory, Woods Hole, MA 02543
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16
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Farhadifar R, Yu CH, Fabig G, Wu HY, Stein DB, Rockman M, Müller-Reichert T, Shelley MJ, Needleman DJ. Stoichiometric interactions explain spindle dynamics and scaling across 100 million years of nematode evolution. eLife 2020; 9:e55877. [PMID: 32966209 PMCID: PMC7511230 DOI: 10.7554/elife.55877] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 08/31/2020] [Indexed: 01/17/2023] Open
Abstract
The spindle shows remarkable diversity, and changes in an integrated fashion, as cells vary over evolution. Here, we provide a mechanistic explanation for variations in the first mitotic spindle in nematodes. We used a combination of quantitative genetics and biophysics to rule out broad classes of models of the regulation of spindle length and dynamics, and to establish the importance of a balance of cortical pulling forces acting in different directions. These experiments led us to construct a model of cortical pulling forces in which the stoichiometric interactions of microtubules and force generators (each force generator can bind only one microtubule), is key to explaining the dynamics of spindle positioning and elongation, and spindle final length and scaling with cell size. This model accounts for variations in all the spindle traits we studied here, both within species and across nematode species spanning over 100 million years of evolution.
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Affiliation(s)
- Reza Farhadifar
- Department of Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard UniversityCambridgeUnited States
- Center for Computational Biology, Flatiron InstituteNew YorkUnited States
| | - Che-Hang Yu
- Department of Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard UniversityCambridgeUnited States
| | - Gunar Fabig
- Experimental Center, Faculty of Medicine Carl Gustav CarusDresdenGermany
| | - Hai-Yin Wu
- Department of Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard UniversityCambridgeUnited States
| | - David B Stein
- Center for Computational Biology, Flatiron InstituteNew YorkUnited States
| | - Matthew Rockman
- Department of Biology and Center for Genomics & Systems Biology, New York UniversityNew YorkUnited States
| | | | - Michael J Shelley
- Center for Computational Biology, Flatiron InstituteNew YorkUnited States
- Courant Institute, New York UniversityNew YorkUnited States
| | - Daniel J Needleman
- Department of Molecular and Cellular Biology and School of Engineering and Applied Sciences, Harvard UniversityCambridgeUnited States
- Center for Computational Biology, Flatiron InstituteNew YorkUnited States
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17
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Burakov AV, Nadezhdina ES. Centering and Shifting of Centrosomes in Cells. Cells 2020; 9:E1351. [PMID: 32485978 PMCID: PMC7348834 DOI: 10.3390/cells9061351] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 05/24/2020] [Accepted: 05/27/2020] [Indexed: 12/16/2022] Open
Abstract
Centrosomes have a nonrandom localization in the cells: either they occupy the centroid of the zone free of the actomyosin cortex or they are shifted to the edge of the cell, where their presence is justified from a functional point of view, for example, to organize additional microtubules or primary cilia. This review discusses centrosome placement options in cultured and in situ cells. It has been proven that the central arrangement of centrosomes is due mainly to the pulling microtubules forces developed by dynein located on the cell cortex and intracellular vesicles. The pushing forces from dynamic microtubules and actomyosin also contribute, although the molecular mechanisms of their action have not yet been elucidated. Centrosomal displacement is caused by external cues, depending on signaling, and is drawn through the redistribution of dynein, the asymmetrization of microtubules through the capture of their plus ends, and the redistribution of actomyosin, which, in turn, is associated with basal-apical cell polarization.
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Affiliation(s)
- Anton V. Burakov
- A. N. Belozersky Institute of Physico-Chemical Biology, M. V. Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Elena S. Nadezhdina
- Institute of Protein Research of Russian Academy of Science, Pushchino, 142290 Moscow Region, Russia
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18
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Stiff T, Echegaray-Iturra FR, Pink HJ, Herbert A, Reyes-Aldasoro CC, Hochegger H. Prophase-Specific Perinuclear Actin Coordinates Centrosome Separation and Positioning to Ensure Accurate Chromosome Segregation. Cell Rep 2020; 31:107681. [PMID: 32460023 PMCID: PMC7262599 DOI: 10.1016/j.celrep.2020.107681] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 02/11/2020] [Accepted: 05/01/2020] [Indexed: 12/30/2022] Open
Abstract
Centrosome separation in late G2/ early prophase requires precise spatial coordination that is determined by a balance of forces promoting and antagonizing separation. The major effector of centrosome separation is the kinesin Eg5. However, the identity and regulation of Eg5-antagonizing forces is less well characterized. By manipulating candidate components, we find that centrosome separation is reversible and that separated centrosomes congress toward a central position underneath the flat nucleus. This positioning mechanism requires microtubule polymerization, as well as actin polymerization. We identify perinuclear actin structures that form in late G2/early prophase and interact with microtubules emanating from the centrosomes. Disrupting these structures by breaking the interactions of the linker of nucleoskeleton and cytoskeleton (LINC) complex with perinuclear actin filaments abrogates this centrosome positioning mechanism and causes an increase in subsequent chromosome segregation errors. Our results demonstrate how geometrical cues from the cell nucleus coordinate the orientation of the emanating spindle poles before nuclear envelope breakdown.
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Affiliation(s)
- Tom Stiff
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN19RQ, UK
| | - Fabio R Echegaray-Iturra
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN19RQ, UK
| | - Harry J Pink
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN19RQ, UK
| | - Alex Herbert
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN19RQ, UK
| | | | - Helfrid Hochegger
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN19RQ, UK.
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19
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Ierushalmi N, Malik-Garbi M, Manhart A, Abu Shah E, Goode BL, Mogilner A, Keren K. Centering and symmetry breaking in confined contracting actomyosin networks. eLife 2020; 9:55368. [PMID: 32314730 PMCID: PMC7173961 DOI: 10.7554/elife.55368] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/19/2020] [Indexed: 11/13/2022] Open
Abstract
Centering and decentering of cellular components is essential for internal organization of cells and their ability to perform basic cellular functions such as division and motility. How cells achieve proper localization of their organelles is still not well-understood, especially in large cells such as oocytes. Here, we study actin-based positioning mechanisms in artificial cells with persistently contracting actomyosin networks, generated by encapsulating cytoplasmic Xenopus egg extracts into cell-sized ‘water-in-oil’ droplets. We observe size-dependent localization of the contraction center, with a symmetric configuration in larger cells and a polar one in smaller cells. Centering is achieved via a hydrodynamic mechanism based on Darcy friction between the contracting network and the surrounding cytoplasm. During symmetry breaking, transient attachments to the cell boundary drive the contraction center to a polar location. The centering mechanism is cell-cycle dependent and weakens considerably during interphase. Our findings demonstrate a robust, yet tunable, mechanism for subcellular localization. In order to survive, cells need to react to their environment and change their shape or the localization of their internal components. For example, the nucleus – the compartment that contains the genetic information – is often localized at the center of the cell, but it can also be positioned at the side, for instance when cells move or divide asymmetrically. Cells use multiple positioning mechanisms to move their internal components, including a process that relies on networks of filaments made of a protein known as actin. These networks are constantly remodeled as actin proteins are added and removed from the network. Embedded molecular motors can cause the network of actin filaments to contract and push or pull on the compartments. Yet, the exact way these networks localize components in the cell remains unclear, especially in eggs and other large cells. To investigate this question, Ierushalmi et al. studied the actin networks in artificial cells that they created by enclosing the contents of frog eggs in small droplets surrounded by oil. This showed that the networks contracted either to the center of the cell or to its side. Friction between the contracting actin network and the fluid in the cell generated a force that tends to push the contraction center towards the middle of the cell. In larger cells, this led to the centering of the actin network. In smaller cells however, the network transiently attached to the boundary of the cell, leading the contraction center to be pulled to one side. By developing simpler artificial cells that mimic the positioning processes seen in real-life cells, Ierushalmi et al. discovered new mechanisms for how cells may center or de-center their components. This knowledge may be useful to understand diseases that can emerge when the nucleus or other compartments fail to move to the right location, and which are associated with certain organs developing incorrectly.
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Affiliation(s)
- Niv Ierushalmi
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel
| | - Maya Malik-Garbi
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel
| | - Angelika Manhart
- Department of Mathematics, University College London, London, United Kingdom
| | - Enas Abu Shah
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel.,Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, United States
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences and Department of Biology, New York University, New York, United States
| | - Kinneret Keren
- Department of Physics, Technion- Israel Institute of Technology, Haifa, Israel.,Network Biology Research Laboratories and Russell Berrie Nanotechnology Institute, Technion - Israel Institute of Technology, Haifa, Israel
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20
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Ge S, Li J, Huang D, Cai Y, Fang J, Jiang H, Hu B. Strong static magnetic field delayed the early development of zebrafish. Open Biol 2019; 9:190137. [PMID: 31662097 PMCID: PMC6833226 DOI: 10.1098/rsob.190137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
One of the major topics in magnetobiology is the biological effects of strong static magnetic field (SMF) on living organisms. However, there has been a paucity of the comprehensive study of the long-term effects of strong SMF on an animal's development. Here, we explored this question with zebrafish, an excellent model organism for developmental study. In our research, zebrafish eggs, just after fertilization, were exposed to a 9.0 T SMF for 24 h, the critical period of post-fertilization development from cleavage to segmentation. The effects of strong SMF exposure on the following developmental progress of zebrafish were studied until 6 days post-fertilization (dpf). Results showed that 9.0 T SMF exposure did not influence the survival or the general developmental scenario of zebrafish embryos. However, it slowed down the developmental pace of the whole animal, and the late developers would catch up with their control peers after the SMF was removed. We proposed a mechanical model and deduced that the development delaying effect was caused by the interference of SMF in microtubule and spindle positioning during mitosis, especially in early cleavages. Our research data provide insights into how strong SMF influences the developing organisms through basic physical interactions with intracellular macromolecules.
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Affiliation(s)
- Shuchao Ge
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Jingchen Li
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Dengfeng Huang
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Yuan Cai
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Jun Fang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Science, Hefei, Anhui 230031, People's Republic of China
| | - Hongyuan Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Bing Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, CAS Key Laboratory of Brain Function and Disease, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
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21
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Li J, Cheng L, Jiang H. Cell shape and intercellular adhesion regulate mitotic spindle orientation. Mol Biol Cell 2019; 30:2458-2468. [PMID: 31411941 PMCID: PMC6743358 DOI: 10.1091/mbc.e19-04-0227] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cell division orientation plays an essential role in tissue morphogenesis and cell fate decision. Recent studies showed that either cell shape or adhesion geometry can regulate the orientation of mitotic spindles and thereby the cell division orientation. However, how they together regulate the spindle orientation remains largely unclear. In this work, we use a general computational model to investigate the competitive mechanism of determining the spindle orientation between cell shape and intercellular adhesion in epithelial cells. We find the spindle orientation is dominated by the intercellular adhesion when the cell shape anisotropy is small, but dominated by the cell shape when the shape anisotropy is large. A strong adhesion and moderate adhesive size can ensure the planar division of epithelial cells with large apico-basal elongation. We also find the spindle orientation could be perpendicular to the adhesive region when only one side of the cell is adhered to an E-cadherin-coated matrix. But after the cell is compressed, the spindle orientation is governed by the cell shape and the spindle will be parallel to the adhesive region when the cell shape anisotropy is large. Finally, we demonstrate the competition between cell shape and tricellular junctions can also effectively regulate the spindle orientation.
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Affiliation(s)
- Jingchen Li
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Longcan Cheng
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hongyuan Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Hefei National Laboratory for Physical Science at the Microscale, Department of Modern Mechanics, CAS Center for Excellence in Complex System Mechanics, University of Science and Technology of China, Hefei, Anhui 230026, China
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22
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Odell J, Sikirzhytski V, Tikhonenko I, Cobani S, Khodjakov A, Koonce M. Force balances between interphase centrosomes as revealed by laser ablation. Mol Biol Cell 2019; 30:1705-1715. [PMID: 31067156 PMCID: PMC6727758 DOI: 10.1091/mbc.e19-01-0034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Numerous studies have highlighted the self-centering activities of individual microtubule (MT) arrays in animal cells, but relatively few works address the behavior of multiple arrays that coexist in a common cytoplasm. In multinucleated Dictyostelium discoideum cells, each centrosome organizes a radial MT network, and these networks remain separate from one another. This feature offers an opportunity to reveal the mechanism(s) responsible for the positioning of multiple centrosomes. Using a laser microbeam to eliminate one of the two centrosomes in binucleate cells, we show that the unaltered array is rapidly repositioned at the cell center. This result demonstrates that each MT array is constantly subject to centering forces and infers a mechanism to balance the positions of multiple arrays. Our results address the limited actions of three kinesins and a cross-linking MAP that are known to have effects in maintaining MT organization and suggest a simple means used to keep the arrays separated.
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Affiliation(s)
- Jacob Odell
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
| | - Vitali Sikirzhytski
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
| | - Irina Tikhonenko
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
| | - Sonila Cobani
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
| | - Alexey Khodjakov
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
| | - Michael Koonce
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509
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23
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Sarkar A, Rieger H, Paul R. Search and Capture Efficiency of Dynamic Microtubules for Centrosome Relocation during IS Formation. Biophys J 2019; 116:2079-2091. [PMID: 31084903 DOI: 10.1016/j.bpj.2019.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 04/08/2019] [Indexed: 11/29/2022] Open
Abstract
Upon contact with antigen-presenting cells, cytotoxic T lymphocytes (T cells) establish a highly organized contact zone denoted as the immunological synapse (IS). The formation of the IS implies relocation of the microtubule organizing center (MTOC) toward the contact zone, which necessitates a proper connection between the MTOC and the IS via dynamic microtubules (MTs). The efficiency of the MTs finding the IS within the relevant timescale is, however, still illusive. We investigate how MTs search the three-dimensional constrained cellular volume for the IS and bind upon encounter to dynein anchored at the IS cortex. The search efficiency is estimated by calculating the time required for the MTs to reach the dynein-enriched region of the IS. In this study, we develop simple mathematical and numerical models incorporating relevant components of a cell and propose an optimal search strategy. Using the mathematical model, we have quantified the average search time for a wide range of model parameters and proposed an optimized set of values leading to the minimal capture time. Our results show that search times are minimal when the IS formed at the nearest or at the farthest sites on the cell surface with respect to the perinuclear MTOC. The search time increases monotonically away from these two specific sites and is maximal at an intermediate position near the equator of the cell. We observed that search time strongly depends on the number of searching MTs and distance of the MTOC from the nuclear surface.
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Affiliation(s)
- Apurba Sarkar
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Kolkata, West Bengal, India.
| | - Heiko Rieger
- Department of Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany.
| | - Raja Paul
- School of Mathematical & Computational Sciences, Indian Association for the Cultivation of Science, Kolkata, West Bengal, India.
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24
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Som S, Chatterjee S, Paul R. Mechanistic three-dimensional model to study centrosome positioning in the interphase cell. Phys Rev E 2019; 99:012409. [PMID: 30780383 DOI: 10.1103/physreve.99.012409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Indexed: 01/28/2023]
Abstract
During the interphase in mammalian cells, the position of the centrosome is actively maintained at a small but finite distance away from the nucleus. The perinuclear positioning of the centrosome is crucial for cellular trafficking and progression into mitosis. Although the literature suggests that the contributions of the microtubule-associated forces bring the centrosome to the center of the cell, the position of the centrosome was merely investigated in the absence of the nucleus. Upon performing a coarse-grained simulation study with mathematical analysis, we show that the combined effect of the forces due to the cell cortex and the nucleus facilitate the centrosome positioning. Our study also demonstrates that in the absence of nucleus-based forces, the centrosome collapses on the nucleus due to cortical forces. Depending upon the magnitudes of the cortical forces and the nucleus-based forces, the centrosome appears to stay at various distances away from the nucleus. Such null force regions are found to be stable as well as unstable fixed points. This study uncovers a set of redundant schemes that the cell may adopt to produce the required cortical and nucleus-based forces stabilizing the centrosome at a finite distance away from the nucleus.
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Affiliation(s)
- Subhendu Som
- Indian Association for the Cultivation of Science, Kolkata - 700032, India
| | | | - Raja Paul
- Indian Association for the Cultivation of Science, Kolkata - 700032, India
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25
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Abstract
For over a century, the centrosome has been an organelle more easily tracked than understood, and the study of its peregrinations within the cell remains a chief underpinning of its functional investigation. Increasing attention and new approaches have been brought to bear on mechanisms that control centrosome localization in the context of cleavage plane determination, ciliogenesis, directional migration, and immunological synapse formation, among other cellular and developmental processes. The Golgi complex, often linked with the centrosome, presents a contrasting case of a pleiomorphic organelle for which functional studies advanced somewhat more rapidly than positional tracking. However, Golgi orientation and distribution has emerged as an area of considerable interest with respect to polarized cellular function. This chapter will review our current understanding of the mechanism and significance of the positioning of these organelles.
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26
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Roman AC, Garrido-Jimenez S, Diaz-Chamorro S, Centeno F, Carvajal-Gonzalez JM. Centriole Positioning: Not Just a Little Dot in the Cell. Results Probl Cell Differ 2019; 67:201-221. [PMID: 31435796 DOI: 10.1007/978-3-030-23173-6_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Organelle positioning as many other morphological parameters in a cell is not random. Centriole positioning as centrosomes or ciliary basal bodies is not an exception to this rule in cell biology. Indeed, centriole positioning is a tightly regulated process that occurs during development, and it is critical for many organs to function properly, not just during development but also in the adulthood. In this book chapter, we overview our knowledge on centriole positioning in different and highly specialized animal cells like photoreceptor or ependymal cells. We will also discuss recent advances in the discovery of molecular pathways involved in this process, mostly related to the cytoskeleton and the cell polarity pathways. And finally, we present quantitative methods that have been used to assess centriole positioning in different cell types although mostly in epithelial cells.
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Affiliation(s)
- Angel-Carlos Roman
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Sergio Garrido-Jimenez
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Selene Diaz-Chamorro
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Francisco Centeno
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Jose Maria Carvajal-Gonzalez
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain.
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27
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Tanimoto H, Sallé J, Dodin L, Minc N. Physical Forces Determining the Persistency and Centering Precision of Microtubule Asters. NATURE PHYSICS 2018; 14:848-854. [PMID: 30079097 PMCID: PMC6071857 DOI: 10.1038/s41567-018-0154-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 04/24/2018] [Indexed: 05/24/2023]
Abstract
In early embryos, microtubules form star-shaped aster structures that can measure up to hundreds of micrometres, and move at high speeds to find the geometrical centre of the cell. This process, known as aster centration, is essential for the fidelity of cell division and development, but how cells succeed in moving these large structures through their crowded and fluctuating cytoplasm remains unclear. Here, we demonstrate that the positional fluctuations of migrating sea urchin sperm asters are small, anisotropic, and associated with the stochasticity of dynein-dependent forces moving the aster. Using in vivo magnetic tweezers to directly measure aster forces inside cells, we derive a linear aster force-velocity relationship and provide evidence for a spring-like active mechanism stabilizing the transverse position of the asters. The large frictional coefficient and spring constant quantitatively account for the amplitude and growth characteristics of athermal positional fluctuations, demonstrating that aster mechanics ensure noise suppression to promote persistent and precise centration. These findings define generic biophysical regimes of active cytoskeletal mechanics underlying the accuracy of cell division and early embryonic development.
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Affiliation(s)
- Hirokazu Tanimoto
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Jeremy Sallé
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Louise Dodin
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Nicolas Minc
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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28
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Zulkipli I, Clark J, Hart M, Shrestha RL, Gul P, Dang D, Kasichiwin T, Kujawiak I, Sastry N, Draviam VM. Spindle rotation in human cells is reliant on a MARK2-mediated equatorial spindle-centering mechanism. J Cell Biol 2018; 217:3057-3070. [PMID: 29941476 PMCID: PMC6122980 DOI: 10.1083/jcb.201804166] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/18/2018] [Accepted: 05/24/2018] [Indexed: 12/11/2022] Open
Abstract
Unlike man-made wheels that are centered and rotated via an axle, the mitotic spindle of a human cell is rotated by external cortical pulling mechanisms. Zulkipli et al. identify MARK2’s role in equatorial spindle centering and astral microtubule length, which in turn control spindle rotation. The plane of cell division is defined by the final position of the mitotic spindle. The spindle is pulled and rotated to the correct position by cortical dynein. However, it is unclear how the spindle’s rotational center is maintained and what the consequences of an equatorially off centered spindle are in human cells. We analyzed spindle movements in 100s of cells exposed to protein depletions or drug treatments and uncovered a novel role for MARK2 in maintaining the spindle at the cell’s geometric center. Following MARK2 depletion, spindles glide along the cell cortex, leading to a failure in identifying the correct division plane. Surprisingly, spindle off centering in MARK2-depleted cells is not caused by excessive pull by dynein. We show that MARK2 modulates mitotic microtubule growth and length and that codepleting mitotic centromere-associated protein (MCAK), a microtubule destabilizer, rescues spindle off centering in MARK2-depleted cells. Thus, we provide the first insight into a spindle-centering mechanism needed for proper spindle rotation and, in turn, the correct division plane in human cells.
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Affiliation(s)
- Ihsan Zulkipli
- Department of Genetics, University of Cambridge, Cambridge, England, UK
| | - Joanna Clark
- Department of Genetics, University of Cambridge, Cambridge, England, UK
| | - Madeleine Hart
- School of Biological and Chemical Sciences, Queen Mary University of London, London, England, UK
| | - Roshan L Shrestha
- Department of Genetics, University of Cambridge, Cambridge, England, UK
| | - Parveen Gul
- School of Biological and Chemical Sciences, Queen Mary University of London, London, England, UK
| | - David Dang
- School of Biological and Chemical Sciences, Queen Mary University of London, London, England, UK.,Department of Informatics, King's College, London, England, UK
| | - Tami Kasichiwin
- School of Biological and Chemical Sciences, Queen Mary University of London, London, England, UK
| | - Izabela Kujawiak
- Department of Genetics, University of Cambridge, Cambridge, England, UK
| | - Nishanth Sastry
- Department of Informatics, King's College, London, England, UK
| | - Viji M Draviam
- School of Biological and Chemical Sciences, Queen Mary University of London, London, England, UK .,Department of Genetics, University of Cambridge, Cambridge, England, UK
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29
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Haupt A, Minc N. How cells sense their own shape - mechanisms to probe cell geometry and their implications in cellular organization and function. J Cell Sci 2018; 131:131/6/jcs214015. [PMID: 29581183 DOI: 10.1242/jcs.214015] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Cells come in a variety of shapes that most often underlie their functions. Regulation of cell morphogenesis implies that there are mechanisms for shape sensing that still remain poorly appreciated. Global and local cell geometry features, such as aspect ratio, size or membrane curvature, may be probed by intracellular modules, such as the cytoskeleton, reaction-diffusion systems or molecular complexes. In multicellular tissues, cell shape emerges as an important means to transduce tissue-inherent chemical and mechanical cues into intracellular organization. One emergent paradigm is that cell-shape sensing is most often based upon mechanisms of self-organization, rather than determinism. Here, we review relevant work that has elucidated some of the core principles of how cellular geometry may be conveyed into spatial information to guide processes, such as polarity, signaling, morphogenesis and division-plane positioning.
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Affiliation(s)
- Armin Haupt
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Nicolas Minc
- Institut Jacques Monod, CNRS UMR7592 and Université Paris Diderot, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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30
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De Simone A, Spahr A, Busso C, Gönczy P. Uncovering the balance of forces driving microtubule aster migration in C. elegans zygotes. Nat Commun 2018; 9:938. [PMID: 29507295 PMCID: PMC5838244 DOI: 10.1038/s41467-018-03118-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 01/18/2018] [Indexed: 11/09/2022] Open
Abstract
Microtubule asters must be positioned precisely within cells. How forces generated by molecular motors such as dynein are integrated in space and time to enable such positioning remains unclear. In particular, whereas aster movements depend on the drag caused by cytoplasm viscosity, in vivo drag measurements are lacking, precluding a thorough understanding of the mechanisms governing aster positioning. Here, we investigate this fundamental question during the migration of asters and pronuclei in C. elegans zygotes, a process essential for the mixing of parental genomes. Detailed quantification of these movements using the female pronucleus as an in vivo probe establish that the drag coefficient of the male-asters complex is approximately five times that of the female pronucleus. Further analysis of embryos lacking cortical dynein, the connection between asters and male pronucleus, or the male pronucleus altogether, uncovers the balance of dynein-driven forces that accurately position microtubule asters in C. elegans zygotes. Microtubule asters are positioned precisely within cells by forces generated by molecular motors, but it is unclear how these are integrated in space and time. Here the authors perform in vivo drag measurements and genetic manipulations to determine the balance of forces that position microtubule asters in C. elegans zygotes.
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Affiliation(s)
- A De Simone
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland.,Department of Cell Biology, Duke University Medical Center, Durham, NC, 27710, USA
| | - A Spahr
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - C Busso
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - P Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology Lausanne (EPFL), 1015, Lausanne, Switzerland.
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31
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Li J, Jiang H. Regulating positioning and orientation of mitotic spindles via cell size and shape. Phys Rev E 2018; 97:012407. [PMID: 29448469 DOI: 10.1103/physreve.97.012407] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Indexed: 06/08/2023]
Abstract
Proper location of the mitotic spindle is critical for chromosome segregation and the selection of the cell division plane. However, how mitotic spindles sense cell size and shape to regulate their own position and orientation is still largely unclear. To investigate this question systematically, we used a general model by considering chromosomes, microtubule dynamics, and forces of various molecular motors. Our results show that in cells of various sizes and shapes, spindles can always be centered and oriented along the long axis robustly in the absence of other specified mechanisms. We found that the characteristic time of positioning and orientation processes increases with cell size. Spindles sense the cell size mainly by the cortical force in small cells and by the cytoplasmic force in large cells. In addition to the cell size, the cell shape mainly influences the orientation process. We found that more slender cells have a faster orientation process, and the final orientation is not necessarily along the longest axis but is determined by the radial profile and the symmetry of the cell shape. Finally, our model also reproduces the separation and repositioning of the spindle poles during the anaphase. Therefore, our work provides a general tool for studying the mitotic spindle across the whole mitotic phase.
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Affiliation(s)
- Jingchen Li
- Department of Modern Mechanics, CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Hongyuan Jiang
- Department of Modern Mechanics, CAS Key Laboratory of Mechanical Behavior and Design of Materials, University of Science and Technology of China, Hefei, Anhui 230027, China
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32
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Ghosh S, Pradeep VNS, Muhuri S, Pagonabarraga I, Chaudhuri D. Bidirectional motion of filaments: the role of motor proteins and passive cross linkers. SOFT MATTER 2017; 13:7129-7140. [PMID: 28858369 DOI: 10.1039/c7sm01110e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In eukaryotic cells, motor proteins (MPs) bind to cytoskeletal filaments and move along them in a directed manner generating active stresses. During cell division a spindle structure of overlapping antiparallel microtubules forms whose stability and dynamics under the influence of MPs have been studied extensively. Although passive cross linkers (PCLs) are known to provide structural stability to a filamentous network, consequences of the interplay between ATP dependent active forces of MPs and passive entropic forces of PCLs on filamentous overlap remain largely unexplored. Here, we formulate and characterize a model to study this, using linear stability analysis and numerical integration. In the presence of PCLs, we find dynamic phase transitions with changing activity exhibiting regimes of stable partial overlap with or without oscillations, instability towards complete overlap, and stable limit cycle oscillations that emerge via a supercritical Hopf bifurcation characterized by an oscillation frequency determined by the MP and PCL parameters. We show that the overlap dynamics and stability depend crucially on whether both the filaments of an overlapping pair are movable or one is immobilized, having potential implications for in vivo and in vitro studies.
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Affiliation(s)
- Subhadip Ghosh
- Institute of Physics, Sachivalaya Marg, Bhubaneswar 751005, India.
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33
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Pitaval A, Senger F, Letort G, Gidrol X, Guyon L, Sillibourne J, Théry M. Microtubule stabilization drives 3D centrosome migration to initiate primary ciliogenesis. J Cell Biol 2017; 216:3713-3728. [PMID: 28993469 PMCID: PMC5674878 DOI: 10.1083/jcb.201610039] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 06/02/2017] [Accepted: 08/17/2017] [Indexed: 01/09/2023] Open
Abstract
The classical view of centrosome decentering and migration to the cell periphery during ciliogenesis is that it is pulled toward its final destination. Here, Pitaval et al. argue that microtubule stabilization in the early stages of ciliogenesis generates pushing forces that propel the centrosome toward the apical pole. Primary cilia are sensory organelles located at the cell surface. Their assembly is primed by centrosome migration to the apical surface, yet surprisingly little is known about this initiating step. To gain insight into the mechanisms driving centrosome migration, we exploited the reproducibility of cell architecture on adhesive micropatterns to investigate the cytoskeletal remodeling supporting it. Microtubule network densification and bundling, with the transient formation of an array of cold-stable microtubules, and actin cytoskeleton asymmetrical contraction participate in concert to drive apical centrosome migration. The distal appendage protein Cep164 appears to be a key actor involved in the cytoskeleton remodeling and centrosome migration, whereas intraflagellar transport 88’s role seems to be restricted to axoneme elongation. Together, our data elucidate the hitherto unexplored mechanism of centrosome migration and show that it is driven by the increase and clustering of mechanical forces to push the centrosome toward the cell apical pole.
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Affiliation(s)
- Amandine Pitaval
- UMR_S 1038, Biomics Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Santé et de la Recherche, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France.,UMR 5168, CytoMorpho Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France
| | - Fabrice Senger
- UMR 5168, CytoMorpho Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France
| | - Gaëlle Letort
- UMR 5168, CytoMorpho Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France
| | - Xavier Gidrol
- UMR_S 1038, Biomics Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Santé et de la Recherche, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France
| | - Laurent Guyon
- UMR_S 1036, Biologie du Cancer et de l'Infection, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Santé et de la Recherche, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France
| | - James Sillibourne
- UMR 5168, CytoMorpho Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France .,UMRS 1160, CytoMorpho Lab, University Paris Diderot, Institut National de la Santé et de la Recherche, Hôpital Saint Louis, Institut Universitaire d'Hematologie, Paris, France
| | - Manuel Théry
- UMR 5168, CytoMorpho Lab, University Grenoble-Alpes, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble, France .,UMRS 1160, CytoMorpho Lab, University Paris Diderot, Institut National de la Santé et de la Recherche, Hôpital Saint Louis, Institut Universitaire d'Hematologie, Paris, France
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Zhang J, Wang YL. Centrosome defines the rear of cells during mesenchymal migration. Mol Biol Cell 2017; 28:3240-3251. [PMID: 28855377 PMCID: PMC5687026 DOI: 10.1091/mbc.e17-06-0366] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 11/12/2022] Open
Abstract
Taking advantage of the strong polarity of cells migrating along micropatterned lines, combined with computational modeling and microsurgery, we found that the centrosome must be localized toward the rear of a cell, likely for controlling the distribution of tail formation signals. This discovery clarifies a long-standing controversy in cell biology. The importance of centrosome in directional cell migration has long been recognized. However, the conventional view that centrosome determines cell’s front, based on its often-observed position in front of the nucleus, has been challenged by contradictory observations. Here we show that centrosome defines the rear instead of the front, using cells plated on micropatterned adhesive strips to facilitate directional migration. We found that centrosome is always located proximal to the future rear before polarity is established through symmetry breaking or reversed as the cell reaches a dead end. In addition, using microsurgery to alter the distance of centrosomes from cells’ ends, we show that centrosomal proximity is predictive of the placement of the rear. Removal of centrosome impairs directional cell migration, whereas the removal of nucleus alone makes no difference in most cells. Computer modeling under the framework of a local-enhancement/global-inhibition mechanism further demonstrates that positioning of rear retraction, mediated by signals concentrated near the centrosome, recapitulates all the experimental observations. Our results resolve a long-standing controversy and explain how cells use centrosome and microtubules to maintain directional migration.
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Affiliation(s)
- Jian Zhang
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Yu-Li Wang
- Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213
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35
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Mechanosensing in the immune response. Semin Cell Dev Biol 2017; 71:137-145. [PMID: 28830744 DOI: 10.1016/j.semcdb.2017.08.031] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/11/2017] [Accepted: 08/14/2017] [Indexed: 01/16/2023]
Abstract
Cells have a remarkable ability to sense and respond to the mechanical properties of their environment. Mechanosensing is essential for many phenomena, ranging from cell movements and tissue rearrangements to cell differentiation and the immune response. Cells of the immune system get activated when membrane receptors bind to cognate antigen on the surface of antigen presenting cells. Both T and B lymphocyte signaling has been shown to be responsive to physical forces and mechanical cues. Cytoskeletal forces exerted by cells likely mediate this mechanical modulation. Here, we discuss recent advances in the field of immune cell mechanobiology at the molecular and cellular scale.
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36
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Geometric Asymmetry Induces Upper Limit of Mitotic Spindle Size. Biophys J 2017; 112:1503-1516. [PMID: 28402892 DOI: 10.1016/j.bpj.2017.02.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 02/10/2017] [Accepted: 02/23/2017] [Indexed: 01/10/2023] Open
Abstract
Proper organelle size is critical for many cell functions. However, how cells sense and control their organelle size remains elusive. Here, we develop a general model to study the size control of mitotic spindles by considering both extrinsic and intrinsic factors, such as the limited number of building blocks of the spindle, the interaction between the spindle and cell boundary, the DNA content, the forces generated by various molecular motors, and the dynamics of microtubules. We show that multiple pairs of chromatids, two centrosomes, and microtubules can self-assemble to form a mitotic spindle robustly. We also show that the boundary-sensing and volume-sensing mechanisms coexist in small cells, but both break down in large cells. Strikingly, we find that the upper limit of spindle length naturally arises from the geometric asymmetry of the spindle structure. Thus, our findings reveal, to our knowledge, a novel intrinsic mechanism that limits the organelle size.
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37
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Carvajal-Gonzalez JM, Mulero-Navarro S, Mlodzik M. Centriole positioning in epithelial cells and its intimate relationship with planar cell polarity. Bioessays 2016; 38:1234-1245. [PMID: 27774671 DOI: 10.1002/bies.201600154] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Planar cell polarity (PCP)-signaling and associated tissue polarization are evolutionarily conserved. A well documented feature of PCP-signaling in vertebrates is its link to centriole/cilia positioning, although the relationship of PCP and ciliogenesis is still debated. A recent report in Drosophila established that Frizzled (Fz)-PCP core signaling has an instructive input to polarized centriole positioning in non-ciliated Drosophila wing epithelia as a PCP read-out. Here, we review the impact of this observation in the context of recent descriptions of the relationship(s) of core Fz-PCP signaling and cilia/centriole positioning in epithelial and non-epithelial cells. All existing data are consistent with a model where Fz-PCP signaling functions upstream of centriole/cilia positioning, independent of ciliogenesis. The combined data sets indicate that the Fz-Dsh PCP complex is instructive for centriole/ciliary positioning via an actin-based mechanism. Thereby, centriole/cilia/centrosome positioning can be considered an evolutionarily conserved readout and common downstream effect of PCP-signaling from flies to mammals.
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Affiliation(s)
- Jose Maria Carvajal-Gonzalez
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Sonia Mulero-Navarro
- Departamento de Bioquímica, Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Marek Mlodzik
- Department of Developmental and Regenerative Biology and Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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38
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Kent IA, Lele TP. Microtubule-based force generation. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2016; 9. [PMID: 27562344 DOI: 10.1002/wnan.1428] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/20/2016] [Accepted: 07/30/2016] [Indexed: 11/11/2022]
Abstract
Microtubules are vital to many important cell processes, such as cell division, transport of cellular cargo, organelle positioning, and cell migration. Owing to their diverse functions, understanding microtubule function is an important part of cell biological research that can help in combating various diseases. For example, microtubules are an important target of chemotherapeutic drugs such as paclitaxel because of their pivotal role in cell division. Many functions of microtubules relate to the generation of mechanical forces. These forces are generally either a direct result of microtubule polymerization/depolymerization or generated by motor proteins that move processively along microtubules. In this review, we summarize recent efforts to quantify and model force generation by microtubules in the context of microtubule function. WIREs Nanomed Nanobiotechnol 2017, 9:e1428. doi: 10.1002/wnan.1428 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Ian A Kent
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
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39
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Letort G, Nedelec F, Blanchoin L, Théry M. Centrosome centering and decentering by microtubule network rearrangement. Mol Biol Cell 2016; 27:2833-43. [PMID: 27440925 PMCID: PMC5025270 DOI: 10.1091/mbc.e16-06-0395] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 07/11/2016] [Indexed: 11/11/2022] Open
Abstract
Numerical simulations are used to investigate the role of microtubule network architecture in centrosome positioning. Microtubule gliding along cell edges and pivoting around the centrosome are key regulators of the orientation of pushing forces, the magnitude of which depends on the number, dynamics, and stiffness of microtubules. The centrosome is positioned at the cell center by pushing and pulling forces transmitted by microtubules (MTs). Centrosome decentering is often considered to result from asymmetric, cortical pulling forces exerted in particular by molecular motors on MTs and controlled by external cues affecting the cell cortex locally. Here we used numerical simulations to investigate the possibility that it could equally result from the redistribution of pushing forces due to a reorientation of MTs. We first showed that MT gliding along cell edges and pivoting around the centrosome regulate MT rearrangement and thereby direct the spatial distribution of pushing forces, whereas the number, dynamics, and stiffness of MTs determine the magnitude of these forces. By modulating these parameters, we identified different regimes, involving both pushing and pulling forces, characterized by robust centrosome centering, robust off-centering, or “reactive” positioning. In the last-named conditions, weak asymmetric cues can induce a misbalance of pushing and pulling forces, resulting in an abrupt transition from a centered to an off-centered position. Taken together, these results point to the central role played by the configuration of the MTs on the distribution of pushing forces that position the centrosome. We suggest that asymmetric external cues should not be seen as direct driver of centrosome decentering and cell polarization but instead as inducers of an effective reorganization of the MT network, fostering centrosome motion to the cell periphery.
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Affiliation(s)
- Gaëlle Letort
- CytoMorpho Lab, Biosciences and Biotechnology Institute of Grenoble, UMR5168, CEA/INRA/CNRS/Université Grenoble-Alpes, 38054 Grenoble, France
| | - Francois Nedelec
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Laurent Blanchoin
- CytoMorpho Lab, Biosciences and Biotechnology Institute of Grenoble, UMR5168, CEA/INRA/CNRS/Université Grenoble-Alpes, 38054 Grenoble, France CytoMorpho Lab, Hopital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/Université Paris Diderot, 75010 Paris, France
| | - Manuel Théry
- CytoMorpho Lab, Biosciences and Biotechnology Institute of Grenoble, UMR5168, CEA/INRA/CNRS/Université Grenoble-Alpes, 38054 Grenoble, France CytoMorpho Lab, Hopital Saint Louis, Institut Universitaire d'Hematologie, UMRS1160, INSERM/Université Paris Diderot, 75010 Paris, France
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40
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Ou Y, Chan G, Zuo J, Rattner JB, van der Hoorn FA. Purinergic A2b Receptor Activation by Extracellular Cues Affects Positioning of the Centrosome and Nucleus and Causes Reduced Cell Migration. J Biol Chem 2016; 291:15388-403. [PMID: 27226580 DOI: 10.1074/jbc.m116.721241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Indexed: 12/20/2022] Open
Abstract
The tight, relative positioning of the nucleus and centrosome in mammalian cells is important for the regulation of cell migration. Under pathophysiological conditions, the purinergic A2b receptor can regulate cell motility, but the underlying mechanism remains unknown. Expression of A2b, normally low, is increased in tissues experiencing adverse physiological conditions, including hypoxia and inflammation. ATP is released from such cells. We investigated whether extracellular cues can regulate centrosome-nucleus positioning and cell migration. We discovered that hypoxia as well as extracellular ATP cause a reversible increase in the distance between the centrosome and nucleus and reduced cell motility. We uncovered the underlying pathway: both treatments act through the A2b receptor and specifically activate the Epac1/RapGef3 pathway. We show that cells lacking A2b do not respond in this manner to hypoxia or ATP but transfection of A2b restores this response, that Epac1 is critically involved, and that Rap1B is important for the relative positioning of the centrosome and nucleus. Our results represent, to our knowledge, the first report demonstrating that pathophysiological conditions can impact the distance between the centrosome and nucleus. Furthermore, we identify the A2b receptor as a central player in this process.
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Affiliation(s)
- Young Ou
- From the Departments of Biochemistry and Molecular Biology and
| | - Gordon Chan
- the Department of Oncology and Cancer Research Institute of Northern Alberta, University of Alberta, Edmonton, Alberta T6G 1Z2, Canada
| | - Jeremy Zuo
- From the Departments of Biochemistry and Molecular Biology and
| | - Jerome B Rattner
- Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, Alberta T2N 4N1, Canada and
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41
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Tanimoto H, Kimura A, Minc N. Shape-motion relationships of centering microtubule asters. J Cell Biol 2016; 212:777-87. [PMID: 27022090 PMCID: PMC4810306 DOI: 10.1083/jcb.201510064] [Citation(s) in RCA: 50] [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: 10/15/2015] [Accepted: 02/17/2016] [Indexed: 11/22/2022] Open
Abstract
Although mechanisms that contribute to microtubule (MT) aster positioning have been extensively studied, still little is known on how asters move inside cells to faithfully target a cellular location. Here, we study sperm aster centration in sea urchin eggs, as a stereotypical large-scale aster movement with extreme constraints on centering speed and precision. By tracking three-dimensional aster centration dynamics in eggs with manipulated shapes, we show that aster geometry resulting from MT growth and interaction with cell boundaries dictates aster instantaneous directionality, yielding cell shape-dependent centering trajectories. Aster laser surgery and modeling suggest that dynein-dependent MT cytoplasmic pulling forces that scale to MT length function to convert aster geometry into directionality. In contrast, aster speed remains largely independent of aster size, shape, or absolute dynein activity, which suggests it may be predominantly determined by aster growth rate rather than MT force amplitude. These studies begin to define the geometrical principles that control aster movements.
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Affiliation(s)
| | - Akatsuki Kimura
- Department of Genetics, The Graduate University for Advanced Studies (SOKENDAI), Mishima 411-8540, Japan National Institute of Genetics, Mishima 411-8540, Japan Institut Curie, Centre National de la Recherche Scientifique UMR 144, 75248 Paris, France
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42
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Corrigan AM, Shrestha R, Draviam VM, Donald AM. Modeling of Noisy Spindle Dynamics Reveals Separable Contributions to Achieving Correct Orientation. Biophys J 2015; 109:1398-409. [PMID: 26445440 PMCID: PMC4601064 DOI: 10.1016/j.bpj.2015.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/05/2015] [Accepted: 08/11/2015] [Indexed: 12/23/2022] Open
Abstract
The mechanisms by which the mammalian mitotic spindle is guided to a predefined orientation through microtubule-cortex interactions have recently received considerable interest, but there has been no dynamic model that describes spindle movements toward the preferred axis in human cells. Here, we develop a dynamic model based on stochastic activity of cues anisotropically positioned around the cortex of the mitotic cell and we show that the mitotic spindle does not reach equilibrium before chromosome segregation. Our model successfully captures the characteristic experimental behavior of noisy spindle rotation dynamics in human epithelial cells, including a weak underlying bias in the direction of rotation, suppression of motion close to the alignment axis, and the effect of the aspect ratio of the interphase cell shape in defining the final alignment axis. We predict that the force exerted per cue has a value that minimizes the deviation of the spindle from the predefined axis. The model has allowed us to systematically explore the parameter space around experimentally relevant configurations, and predict the mechanistic function of a number of established regulators of spindle orientation, highlighting how physical modeling of a noisy system can lead to functional biological understanding. We provide key insights into measurable parameters in live cells that can help distinguish between mechanisms of microtubule and cortical-cue interactions that jointly control the final orientation of the spindle.
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Affiliation(s)
- Adam M Corrigan
- Department of Genetics, University of Cambridge, UK; Cavendish Laboratory, Department of Physics, University of Cambridge, UK
| | | | | | - Athene M Donald
- Cavendish Laboratory, Department of Physics, University of Cambridge, UK.
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43
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Cell size modulates oscillation, positioning and length of mitotic spindles. Sci Rep 2015; 5:10504. [PMID: 26015263 PMCID: PMC4444851 DOI: 10.1038/srep10504] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/15/2015] [Indexed: 02/05/2023] Open
Abstract
Mitotic spindle is the main subcellular structure that accomplishes the chromosome segregation between daughter cells during cell division. However, how mitotic spindles sense and control their size, position and movement inside the cell still remains unclear. In this paper, we focus on the size effects of mitotic spindles, i.e., how cell size controls various interesting phenomena in the metaphase, such as oscillation, positioning and size limit of mitotic spindles. We systematically studied the frequency doubling phenomenon during chromosome oscillation and found that cell size can regulate the period and amplitude of chromosome oscillation. We found that the relaxation time of the positioning process increases exponentially with cell size. We also showed that the stabler microtubule-kinetochore attachments alone can directly lead to an upper limit of spindle size. Our work not only explains the existing experimental observations, but also provides some interesting predictions that can be verified or rejected by further experiments.
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44
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Elric J, Etienne-Manneville S. Centrosome positioning in polarized cells: common themes and variations. Exp Cell Res 2014; 328:240-8. [PMID: 25218948 DOI: 10.1016/j.yexcr.2014.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 09/01/2014] [Indexed: 12/17/2022]
Abstract
The centrosome position is tightly regulated during the cell cycle and during differentiated cellular functions. Because centrosome organizes the microtubule network to coordinate both intracellular organization and cell signaling, centrosome positioning is crucial to determine either the axis of cell division, the direction of cell migration or the polarized immune response of lymphocytes. Since alteration of centrosome positioning seems to promote cell transformation and tumor spreading, the molecular mechanisms controlling centrosome movement in response to extracellular and intracellular cues are under intense investigation. Evolutionary conserved pathways involving polarity proteins and cytoskeletal rearrangements are emerging as common regulators of centrosome positioning in a wide variety of cellular contexts.
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Affiliation(s)
- Julien Elric
- Institut Pasteur - CNRS URA 2582, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; Université Pierre et Marie Curie, Cellule Pasteur UPMC, rue du Dr Roux, 75015 Paris, France
| | - Sandrine Etienne-Manneville
- Institut Pasteur - CNRS URA 2582, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France.
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Kiss A, Horvath P, Rothballer A, Kutay U, Csucs G. Nuclear motility in glioma cells reveals a cell-line dependent role of various cytoskeletal components. PLoS One 2014; 9:e93431. [PMID: 24691067 PMCID: PMC3972233 DOI: 10.1371/journal.pone.0093431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 03/05/2014] [Indexed: 12/31/2022] Open
Abstract
Nuclear migration is a general term for the movement of the nucleus towards a specific site in the cell. These movements are involved in a number of fundamental biological processes, such as fertilization, cell division, and embryonic development. Despite of its importance, the mechanism of nuclear migration is still poorly understood in mammalian cells. In order to shed light on the mechanical processes underlying nuclear movements, we adapted a micro-patterning based assay. C6 rat and U87 human glioma cells seeded on fibronectin patterns - thereby forced into a bipolar morphology - displayed oscillatory movements of the nucleus or the whole cell, respectively. We found that both the actomyosin system and microtubules are involved in the nuclear/cellular movements of both cell lines, but their contributions are cell-/migration-type specific. Dynein activity was necessary for nuclear migration of C6 cells but active myosin-II was dispensable. On the other hand, coupled nuclear and cellular movements of U87 cells were driven by actomyosin contraction. We explain these cell-line dependent effects by the intrinsic differences in the overall mechanical tension due to the various cytoskeletal elements inside the cell. Our observations showed that the movements of the nucleus and the centrosome are strongly correlated and display large variation, indicating a tight but flexible coupling between them. The data also indicate that the forces responsible for nuclear movements are not acting directly via the centrosome. Based on our observations, we propose a new model for nuclear oscillations in C6 cells in which dynein and microtubule dynamics are the main drivers of nuclear movements. This mechanism is similar to the meiotic nuclear oscillations of Schizosaccharomyces pombe and may be evolutionary conserved.
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Affiliation(s)
- Alexa Kiss
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
| | - Peter Horvath
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
| | | | - Ulrike Kutay
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland
| | - Gabor Csucs
- Institute of Biochemistry, ETH Zurich, Zurich, Switzerland; Light Microscopy and Screening Centre, ETH Zurich, Zurich, Switzerland
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Kloc M, Kubiak JZ, Li XC, Ghobrial RM. The newly found functions of MTOC in immunological response. J Leukoc Biol 2013; 95:417-30. [DOI: 10.1189/jlb.0813468] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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47
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Mazel T, Biesemann A, Krejczy M, Nowald J, Müller O, Dehmelt L. Direct observation of microtubule pushing by cortical dynein in living cells. Mol Biol Cell 2013; 25:95-106. [PMID: 24173713 PMCID: PMC3873897 DOI: 10.1091/mbc.e13-07-0376] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Single-molecule speckle microscopy and computational modeling reveal the relation between cortical dynein complex dynamics and microtubule behavior in mammalian cells. Experimentally observed rapid turnover of dynein complexes at the cell cortex facilitates their search to efficiently capture and push microtubules with leading plus ends. Microtubules are under the influence of forces mediated by cytoplasmic dynein motors associated with the cell cortex. If such microtubules are free to move, they are rapidly transported inside cells. Here we directly observe fluorescent protein–labeled cortical dynein speckles and motile microtubules. We find that several dynein complex subunits, including the heavy chain, the intermediate chain, and the associated dynactin subunit Dctn1 (also known as p150glued) form spatially resolved, dynamic speckles at the cell cortex, which are preferentially associated with microtubules. Measurements of bleaching and dissociation kinetics at the cell cortex reveal that these speckles often contain multiple labeled dynein heavy-chain molecules and turn over rapidly within seconds. The dynamic behavior of microtubules, such as directional movement, bending, or rotation, is influenced by association with dynein speckles, suggesting a direct physical and functional interaction. Our results support a model in which rapid turnover of cell cortex–associated dynein complexes facilitates their search to efficiently capture and push microtubules directionally with leading plus ends.
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Affiliation(s)
- Tomáš Mazel
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, and Fakultät Chemie, Chemische Biologie, Dortmund University of Technology, 44227 Dortmund, Germany
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48
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Teamwork in microtubule motors. Trends Cell Biol 2013; 23:575-82. [PMID: 23877011 DOI: 10.1016/j.tcb.2013.06.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/11/2013] [Accepted: 06/17/2013] [Indexed: 01/10/2023]
Abstract
Diverse cellular processes are driven by the collective force from multiple motor proteins. Disease-causing mutations cause aberrant function of motors, but the impact is observed at a cellular level and beyond, therefore necessitating an understanding of cell mechanics at the level of motor molecules. One way to do this is by measuring the force generated by ensembles of motors in vivo at single-motor resolution. This has been possible for microtubule motor teams that transport intracellular organelles, revealing unexpected differences between collective and single-molecule function. Here we review how the biophysical properties of single motors, and differences therein, may translate into collective motor function during organelle transport and perhaps in other processes outside transport.
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49
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Longoria RA, Shubeita GT. Cargo transport by cytoplasmic Dynein can center embryonic centrosomes. PLoS One 2013; 8:e67710. [PMID: 23840877 PMCID: PMC3698173 DOI: 10.1371/journal.pone.0067710] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/22/2013] [Indexed: 01/06/2023] Open
Abstract
To complete meiosis II in animal cells, the male DNA material needs to meet the female DNA material contained in the female pronucleus at the egg center, but it is not known how the male pronucleus, deposited by the sperm at the periphery of the cell, finds the cell center in large eggs. Pronucleus centering is an active process that appears to involve microtubules and molecular motors. For small and medium-sized cells, the force required to move the centrosome can arise from either microtubule pushing on the cortex, or cortically-attached dynein pulling on microtubules. However, in large cells, such as the fertilized Xenopus laevis embryo, where microtubules are too long to support pushing forces or they do not reach all boundaries before centrosome centering begins, a different force generating mechanism must exist. Here, we present a centrosome positioning model in which the cytosolic drag experienced by cargoes hauled by cytoplasmic dynein on the sperm aster microtubules can move the centrosome towards the cell's center. We find that small, fast cargoes (diameter ∼100 nm, cargo velocity ∼2 µm/s) are sufficient to move the centrosome in the geometry of the Xenopus laevis embryo within the experimentally observed length and time scales.
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Affiliation(s)
- Rafael A. Longoria
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, United States of America
| | - George T. Shubeita
- Center for Nonlinear Dynamics and Department of Physics, The University of Texas at Austin, Austin, Texas, United States of America
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, United States of America
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50
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Diacylglycerol promotes centrosome polarization in T cells via reciprocal localization of dynein and myosin II. Proc Natl Acad Sci U S A 2013; 110:11976-81. [PMID: 23818610 DOI: 10.1073/pnas.1306180110] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Centrosome reorientation to the immunological synapse maintains the specificity of T-cell effector function by facilitating the directional release of cytokines and cytolytic factors toward the antigen-presenting cell. This polarization response is driven by the localized accumulation of diacylglycerol, which recruits multiple protein kinase (PK)C isozymes to the synaptic membrane. Here, we used T-cell receptor (TCR) photoactivation and imaging methodology to demonstrate that PKCs control centrosome dynamics through the reciprocal localization of two motor complexes, dynein and nonmuscle myosin (NM)II. Dynein accumulated in the region of TCR stimulation, whereas NMII clustered in the back of the cell, behind the polarizing centrosome. PKC activity, which shaped both dynein and NMII accumulation within this framework, controlled NMII localization directly by phosphorylating inhibitory sites within the myosin regulatory light chain, thereby suppressing NMII clustering in the region of TCR stimulation. Concurrently, phosphorylation of distinct sites within myosin regulatory light chain by Rho kinase drove NMII clustering in areas behind the centrosome. These results reveal a role for NMII in T-cell polarity and demonstrate how it is regulated by upstream signals.
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