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Kelkar M, Bohec P, Smith MB, Sreenivasan V, Lisica A, Valon L, Ferber E, Baum B, Salbreux G, Charras G. Spindle reorientation in response to mechanical stress is an emergent property of the spindle positioning mechanisms. Proc Natl Acad Sci U S A 2022; 119:e2121868119. [PMID: 35727980 PMCID: PMC9245638 DOI: 10.1073/pnas.2121868119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 04/28/2022] [Indexed: 11/18/2022] Open
Abstract
Proper orientation of the mitotic spindle plays a crucial role in embryos, during tissue development, and in adults, where it functions to dissipate mechanical stress to maintain tissue integrity and homeostasis. While mitotic spindles have been shown to reorient in response to external mechanical stresses, the subcellular cues that mediate spindle reorientation remain unclear. Here, we used a combination of optogenetics and computational modeling to investigate how mitotic spindles respond to inhomogeneous tension within the actomyosin cortex. Strikingly, we found that the optogenetic activation of RhoA only influences spindle orientation when it is induced at both poles of the cell. Under these conditions, the sudden local increase in cortical tension induced by RhoA activation reduces pulling forces exerted by cortical regulators on astral microtubules. This leads to a perturbation of the balance of torques exerted on the spindle, which causes it to rotate. Thus, spindle rotation in response to mechanical stress is an emergent phenomenon arising from the interaction between the spindle positioning machinery and the cell cortex.
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Affiliation(s)
- Manasi Kelkar
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | - Pierre Bohec
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | | | - Varun Sreenivasan
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London SE1 1UL, United Kingdom
- Medical Research Council Centre for Neurodevelopmental Disorders, King’s College London, London SE1 1UL, United Kingdom
| | - Ana Lisica
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | - Léo Valon
- Department of Developmental and Stem Cell Biology, Institut Pasteur, CNRS UMR 3738, 75015 Paris , France
| | - Emma Ferber
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
| | - Buzz Baum
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, United Kingdom
- Division of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
| | - Guillaume Salbreux
- The Francis Crick Institute, London NW1 1AT, United Kingdom
- Department of Genetics and Evolution, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1H 0AH, United Kingdom
- Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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2
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Lam MSY, Lisica A, Ramkumar N, Hunter G, Mao Y, Charras G, Baum B. Isotropic myosin-generated tissue tension is required for the dynamic orientation of the mitotic spindle. Mol Biol Cell 2020; 31:1370-1379. [PMID: 32320325 PMCID: PMC7353144 DOI: 10.1091/mbc.e19-09-0545] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/19/2020] [Accepted: 04/14/2020] [Indexed: 12/01/2022] Open
Abstract
The ability of cells to divide along their longest axis has been proposed to play an important role in maintaining epithelial tissue homeostasis in many systems. Because the division plane is largely set by the position of the anaphase spindle, it is important to understand how spindles become oriented. While several molecules have been identified that play key roles in spindle orientation across systems, most notably Mud/NuMA and cortical dynein, the precise mechanism by which spindles detect and align with the long cell axis remain poorly understood. Here, in exploring the dynamics of spindle orientation in mechanically distinct regions of the fly notum, we find that the ability of cells to properly reorient their divisions depends on local tissue tension. Thus, spindles reorient to align with the long cell axis in regions where isotropic tension is elevated, but fail to do so in elongated cells within the crowded midline, where tension is low, or in regions that have been mechanically isolated from the rest of the tissue via laser ablation. Importantly, these differences in spindle behavior outside and inside the midline can be recapitulated by corresponding changes in tension induced by perturbations that alter nonmuscle myosin II activity. These data lead us to propose that isotropic tension within an epithelium provides cells with a mechanically stable substrate upon which localized cortical motor complexes can act on astral microtubules to orient the spindle.
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Affiliation(s)
| | - Ana Lisica
- London Centre for Nanotechnology
- Institute for the Physics of Living Systems, and
| | | | | | - Yanlan Mao
- MRC Laboratory for Molecular Cell Biology
- Institute for the Physics of Living Systems, and
| | - Guillaume Charras
- London Centre for Nanotechnology
- Institute for the Physics of Living Systems, and
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology
- Institute for the Physics of Living Systems, and
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3
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Fouchard J, Wyatt TPJ, Proag A, Lisica A, Khalilgharibi N, Recho P, Suzanne M, Kabla A, Charras G. Curling of epithelial monolayers reveals coupling between active bending and tissue tension. Proc Natl Acad Sci U S A 2020; 117:9377-9383. [PMID: 32284424 PMCID: PMC7196817 DOI: 10.1073/pnas.1917838117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Epithelial monolayers are two-dimensional cell sheets which compartmentalize the body and organs of multicellular organisms. Their morphogenesis during development or pathology results from patterned endogenous and exogenous forces and their interplay with tissue mechanical properties. In particular, bending of epithelia is thought to result from active torques generated by the polarization of myosin motors along their apicobasal axis. However, the contribution of these out-of-plane forces to morphogenesis remains challenging to evaluate because of the lack of direct mechanical measurement. Here we use epithelial curling to characterize the out-of-plane mechanics of epithelial monolayers. We find that curls of high curvature form spontaneously at the free edge of epithelial monolayers devoid of substrate in vivo and in vitro. Curling originates from an enrichment of myosin in the basal domain that generates an active spontaneous curvature. By measuring the force necessary to flatten curls, we can then estimate the active torques and the bending modulus of the tissue. Finally, we show that the extent of curling is controlled by the interplay between in-plane and out-of-plane stresses in the monolayer. Such mechanical coupling emphasizes a possible role for in-plane stresses in shaping epithelia during morphogenesis.
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Affiliation(s)
- Jonathan Fouchard
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Tom P J Wyatt
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Amsha Proag
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, CNRS, Université Toulouse III Paul Sabatier, Université de Toulouse, 31062 Toulouse, France
| | - Ana Lisica
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Nargess Khalilgharibi
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom
| | - Pierre Recho
- Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom
- Laboratoire Interdisciplinaire de Physique, CNRS, Université Grenoble Alpes, F-38000 Grenoble, France
| | - Magali Suzanne
- Laboratoire de Biologie Cellulaire et Moléculaire du Controle de la Prolifération, Centre de Biologie Intégrative, CNRS, Université Toulouse III Paul Sabatier, Université de Toulouse, 31062 Toulouse, France
| | - Alexandre Kabla
- Department of Engineering, Cambridge University, Cambridge CB2 1PZ, United Kingdom;
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom;
- Institute for the Physics of Living Systems, University College London, London WC1E 6BT, United Kingdom
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
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4
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Wyatt TPJ, Fouchard J, Lisica A, Khalilgharibi N, Baum B, Recho P, Kabla AJ, Charras GT. Actomyosin controls planarity and folding of epithelia in response to compression. Nat Mater 2020; 19:109-117. [PMID: 31451778 DOI: 10.1038/s41563-019-0461-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 07/09/2019] [Indexed: 06/10/2023]
Abstract
Throughout embryonic development and adult life, epithelia are subjected to compressive deformations. While these have been shown to trigger mechanosensitive responses such as cell extrusion and differentiation, which span tens of minutes, little is known about how epithelia adapt to compression over shorter timescales. Here, using suspended epithelia, we uncover the immediate response of epithelial tissues to the application of in-plane compressive strains (5-80%). We show that fast compression induces tissue buckling followed by actomyosin-dependent tissue flattening that erases the buckle within tens of seconds, in both mono- and multi-layered epithelia. Strikingly, we identify a well-defined limit to this response, so that stable folds form in the tissue when compressive strains exceed a 'buckling threshold' of ~35%. A combination of experiment and modelling shows that this behaviour is orchestrated by adaptation of the actomyosin cytoskeleton as it re-establishes tissue tension following compression. Thus, tissue pre-tension allows epithelia to both buffer against deformation and sets their ability to form and retain folds during morphogenesis.
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Affiliation(s)
- Tom P J Wyatt
- London Centre for Nanotechnology, University College London, London, UK
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, UK
| | - Jonathan Fouchard
- London Centre for Nanotechnology, University College London, London, UK
| | - Ana Lisica
- London Centre for Nanotechnology, University College London, London, UK
| | - Nargess Khalilgharibi
- London Centre for Nanotechnology, University College London, London, UK
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
| | - Pierre Recho
- LIPhy, CNRS-UMR 5588, Université Grenoble Alpes, Grenoble, France
- Department of Engineering, Cambridge University, Cambridge, UK
| | | | - Guillaume T Charras
- London Centre for Nanotechnology, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
- Department of Cell and Developmental Biology, University College London, London, UK.
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5
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Wyatt TPJ, Fouchard J, Lisica A, Khalilgharibi N, Baum B, Recho P, Kabla AJ, Charras GT. Actomyosin controls planarity and folding of epithelia in response to compression. Nat Mater 2020; 19:109-117. [PMID: 31451778 DOI: 10.1101/422196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 07/09/2019] [Indexed: 05/20/2023]
Abstract
Throughout embryonic development and adult life, epithelia are subjected to compressive deformations. While these have been shown to trigger mechanosensitive responses such as cell extrusion and differentiation, which span tens of minutes, little is known about how epithelia adapt to compression over shorter timescales. Here, using suspended epithelia, we uncover the immediate response of epithelial tissues to the application of in-plane compressive strains (5-80%). We show that fast compression induces tissue buckling followed by actomyosin-dependent tissue flattening that erases the buckle within tens of seconds, in both mono- and multi-layered epithelia. Strikingly, we identify a well-defined limit to this response, so that stable folds form in the tissue when compressive strains exceed a 'buckling threshold' of ~35%. A combination of experiment and modelling shows that this behaviour is orchestrated by adaptation of the actomyosin cytoskeleton as it re-establishes tissue tension following compression. Thus, tissue pre-tension allows epithelia to both buffer against deformation and sets their ability to form and retain folds during morphogenesis.
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Affiliation(s)
- Tom P J Wyatt
- London Centre for Nanotechnology, University College London, London, UK
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, UK
| | - Jonathan Fouchard
- London Centre for Nanotechnology, University College London, London, UK
| | - Ana Lisica
- London Centre for Nanotechnology, University College London, London, UK
| | - Nargess Khalilgharibi
- London Centre for Nanotechnology, University College London, London, UK
- Centre for Computation, Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, UK
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
| | - Pierre Recho
- LIPhy, CNRS-UMR 5588, Université Grenoble Alpes, Grenoble, France
- Department of Engineering, Cambridge University, Cambridge, UK
| | | | - Guillaume T Charras
- London Centre for Nanotechnology, University College London, London, UK.
- Institute for the Physics of Living Systems, University College London, London, UK.
- Department of Cell and Developmental Biology, University College London, London, UK.
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6
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Lisica A, Grill SW. Optical tweezers studies of transcription by eukaryotic RNA polymerases. Biomol Concepts 2017; 8:1-11. [PMID: 28222010 DOI: 10.1515/bmc-2016-0028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/10/2017] [Indexed: 11/15/2022] Open
Abstract
Transcription is the first step in the expression of genetic information and it is carried out by large macromolecular enzymes called RNA polymerases. Transcription has been studied for many years and with a myriad of experimental techniques, ranging from bulk studies to high-resolution transcript sequencing. In this review, we emphasise the advantages of using single-molecule techniques, particularly optical tweezers, to study transcription dynamics. We give an overview of the latest results in the single-molecule transcription field, focusing on transcription by eukaryotic RNA polymerases. Finally, we evaluate recent quantitative models that describe the biophysics of RNA polymerase translocation and backtracking dynamics.
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Affiliation(s)
- Ana Lisica
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
| | - Stephan W Grill
- BIOTEC, Technical University Dresden, Tatzberg 47/49, D-01307 Dresden, Germany; and Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, D-01307 Dresden, Germany
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7
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Abstract
Transcription is a key process in gene expression, in which RNA polymerases produce a complementary RNA copy from a DNA template. RNA polymerization is frequently interrupted by backtracking, a process in which polymerases perform a random walk along the DNA template. Recovery of polymerases from the transcriptionally inactive backtracked state is determined by a kinetic competition between one-dimensional diffusion and RNA cleavage. Here we describe backtrack recovery as a continuous-time random walk, where the time for a polymerase to recover from a backtrack of a given depth is described as a first-passage time of a random walker to reach an absorbing state. We represent RNA cleavage as a stochastic resetting process and derive exact expressions for the recovery time distributions and mean recovery times from a given initial backtrack depth for both continuous and discrete-lattice descriptions of the random walk. We show that recovery time statistics do not depend on the discreteness of the DNA lattice when the rate of one-dimensional diffusion is large compared to the rate of cleavage.
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Affiliation(s)
- Édgar Roldán
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,Center for Advancing Electronics Dresden, cfaed, Dresden, Germany.,GISC - Grupo Interdisciplinar de Sistemas Complejos, Madrid, Spain
| | - Ana Lisica
- BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | | | - Stephan W Grill
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.,BIOTEC, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
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Malnar M, Lisica A, Hecimovic SK. P2‐245: Lipid traffic jam in Niemann Pick type C disease causes altered endocytosis of APP. Alzheimers Dement 2011. [DOI: 10.1016/j.jalz.2011.05.1128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lisica A, Krolo A, Malnar M, Kosicek M, Hecimovic S. P2‐135: Loss of NPC1 leads to decreased expression of APP at the cell surface and alters APP distribution within endosome compartments. Alzheimers Dement 2009. [DOI: 10.1016/j.jalz.2009.04.446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Ana Krolo
- Rudjer Boskovic InstituteZagrebCroatia
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