1
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Ghosh S, Joshi C, Baskaran A, Hagan MF. Spatiotemporal control of structure and dynamics in a polar active fluid. SOFT MATTER 2024. [PMID: 39188251 DOI: 10.1039/d4sm00547c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
We apply optimal control theory to a model of a polar active fluid (the Toner-Tu model), with the objective of driving the system into particular emergent dynamical behaviors or programming switching between states on demand. We use the effective self-propulsion speed as the control parameter (i.e. the means of external actuation). We identify control protocols that achieve outcomes such as relocating asters to targeted positions, forcing propagating solitary waves to reorient to a particular direction, and switching between stationary asters and propagating fronts. We analyze the solutions to identify generic principles for controlling polar active fluids. Our findings have implications for achieving spatiotemporal control of active polar systems in experiments, particularly in vitro cytoskeletal systems. Additionally, this research paves the way for leveraging optimal control methods to engineer the structure and dynamics of active fluids more broadly.
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Affiliation(s)
- Saptorshi Ghosh
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA.
| | - Chaitanya Joshi
- Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155, USA
| | - Aparna Baskaran
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA.
| | - Michael F Hagan
- Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA.
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2
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Thekkethil N, Köry J, Guo M, Stewart PS, Hill NA, Luo X. Modelling the rheology of living cell cytoplasm: poroviscoelasticity and fluid-to-solid transition. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01854-2. [PMID: 38976113 DOI: 10.1007/s10237-024-01854-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/17/2024] [Indexed: 07/09/2024]
Abstract
Eukaryotic cell rheology has important consequences for vital processes such as adhesion, migration, and differentiation. Experiments indicate that cell cytoplasm can exhibit both elastic and viscous characteristics in different regimes, while the transport of fluid (cytosol) through the cross-linked filamentous scaffold (cytoskeleton) is reminiscent of mass transfer by diffusion through a porous medium. To gain insights into this complex rheological behaviour, we construct a computational model for the cell cytoplasm as a poroviscoelastic material formulated on the principles of nonlinear continuum mechanics, where we model the cytoplasm as a porous viscoelastic scaffold with an embedded viscous fluid flowing between the pores to model the cytosol. Baseline simulations (neglecting the viscosity of the cytosol) indicate that the system exhibits seven different regimes across the parameter space spanned by the viscoelastic relaxation timescale of the cytoskeleton and the poroelastic diffusion timescale; these regimes agree qualitatively with experimental measurements. Furthermore, the theoretical model also allows us to elucidate the additional role of pore fluid viscosity, which enters the system as a distinct viscous timescale. We show that increasing this viscous timescale hinders the passage of the pore fluid (reducing the poroelastic diffusion) and makes the cytoplasm rheology increasingly incompressible, shifting the phase boundaries between the regimes.
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Affiliation(s)
- Namshad Thekkethil
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK.
| | - Jakub Köry
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, USA
| | - Peter S Stewart
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Nicholas A Hill
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
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3
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Conboy JP, Istúriz Petitjean I, van der Net A, Koenderink GH. How cytoskeletal crosstalk makes cells move: Bridging cell-free and cell studies. BIOPHYSICS REVIEWS 2024; 5:021307. [PMID: 38840976 PMCID: PMC11151447 DOI: 10.1063/5.0198119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024]
Abstract
Cell migration is a fundamental process for life and is highly dependent on the dynamical and mechanical properties of the cytoskeleton. Intensive physical and biochemical crosstalk among actin, microtubules, and intermediate filaments ensures their coordination to facilitate and enable migration. In this review, we discuss the different mechanical aspects that govern cell migration and provide, for each mechanical aspect, a novel perspective by juxtaposing two complementary approaches to the biophysical study of cytoskeletal crosstalk: live-cell studies (often referred to as top-down studies) and cell-free studies (often referred to as bottom-up studies). We summarize the main findings from both experimental approaches, and we provide our perspective on bridging the two perspectives to address the open questions of how cytoskeletal crosstalk governs cell migration and makes cells move.
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Affiliation(s)
- James P. Conboy
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Irene Istúriz Petitjean
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Anouk van der Net
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Gijsje H. Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
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4
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Sakamoto R, Murrell MP. F-actin architecture determines the conversion of chemical energy into mechanical work. Nat Commun 2024; 15:3444. [PMID: 38658549 PMCID: PMC11043346 DOI: 10.1038/s41467-024-47593-x] [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: 10/13/2023] [Accepted: 04/03/2024] [Indexed: 04/26/2024] Open
Abstract
Mechanical work serves as the foundation for dynamic cellular processes, ranging from cell division to migration. A fundamental driver of cellular mechanical work is the actin cytoskeleton, composed of filamentous actin (F-actin) and myosin motors, where force generation relies on adenosine triphosphate (ATP) hydrolysis. F-actin architectures, whether bundled by crosslinkers or branched via nucleators, have emerged as pivotal regulators of myosin II force generation. However, it remains unclear how distinct F-actin architectures impact the conversion of chemical energy to mechanical work. Here, we employ in vitro reconstitution of distinct F-actin architectures with purified components to investigate their influence on myosin ATP hydrolysis (consumption). We find that F-actin bundles composed of mixed polarity F-actin hinder network contraction compared to non-crosslinked network and dramatically decelerate ATP consumption rates. Conversely, linear-nucleated networks allow network contraction despite reducing ATP consumption rates. Surprisingly, branched-nucleated networks facilitate high ATP consumption without significant network contraction, suggesting that the branched network dissipates energy without performing work. This study establishes a link between F-actin architecture and myosin energy consumption, elucidating the energetic principles underlying F-actin structure formation and the performance of mechanical work.
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Affiliation(s)
- Ryota Sakamoto
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA.
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5
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Waechtler BE, Jayasankar R, Morin EP, Robinson DN. Benefits and challenges of reconstituting the actin cortex. Cytoskeleton (Hoboken) 2024. [PMID: 38520148 DOI: 10.1002/cm.21855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/05/2024] [Indexed: 03/25/2024]
Abstract
The cell's ability to change shape is a central feature in many cellular processes, including cytokinesis, motility, migration, and tissue formation. The cell constructs a network of contractile proteins underneath the cell membrane to form the cortex, and the reorganization of these components directly contributes to cellular shape changes. The desire to mimic these cell shape changes to aid in the creation of a synthetic cell has been increasing. Therefore, membrane-based reconstitution experiments have flourished, furthering our understanding of the minimal components the cell uses throughout these processes. Although biochemical approaches increased our understanding of actin, myosin II, and actin-associated proteins, using membrane-based reconstituted systems has further expanded our understanding of actin structures and functions because membrane-cortex interactions can be analyzed. In this review, we highlight the recent developments in membrane-based reconstitution techniques. We examine the current findings on the minimal components needed to recapitulate distinct actin structures and functions and how they relate to the cortex's impact on cellular mechanical properties. We also explore how co-processing of computational models with wet-lab experiments enhances our understanding of these properties. Finally, we emphasize the benefits and challenges inherent to membrane-based, reconstitution assays, ranging from the advantage of precise control over the system to the difficulty of integrating these findings into the complex cellular environment.
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Affiliation(s)
- Brooke E Waechtler
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rajan Jayasankar
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland, USA
| | - Emma P Morin
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Baltimore, Maryland, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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6
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Banerjee DS, Freedman SL, Murrell MP, Banerjee S. Growth-induced collective bending and kinetic trapping of cytoskeletal filaments. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574885. [PMID: 38260433 PMCID: PMC10802417 DOI: 10.1101/2024.01.09.574885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Growth and turnover of actin filaments play a crucial role in the construction and maintenance of actin networks within cells. Actin filament growth occurs within limited space and finite subunit resources in the actin cortex. To understand how filament growth shapes the emergent architecture of actin networks, we developed a minimal agent-based model coupling filament mechanics and growth in a limiting subunit pool. We find that rapid filament growth induces kinetic trapping of highly bent actin filaments. Such collective bending patterns are long-lived, organized around nematic defects, and arises from competition between filament polymerization and bending elasticity. The stability of nematic defects and the extent of kinetic trapping are amplified by an increase in the abundance of the actin pool and by crosslinking the network. These findings suggest that kinetic trapping is a robust consequence of growth in crowded environments, providing a route to program shape memory in actin networks.
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Affiliation(s)
- Deb Sankar Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- James Franck Institute, University of Chicago, Chicago, IL 60637, USA
| | | | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA
| | - Shiladitya Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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7
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Najma B, Wei WS, Baskaran A, Foster PJ, Duclos G. Microscopic interactions control a structural transition in active mixtures of microtubules and molecular motors. Proc Natl Acad Sci U S A 2024; 121:e2300174121. [PMID: 38175870 PMCID: PMC10786313 DOI: 10.1073/pnas.2300174121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 10/07/2023] [Indexed: 01/06/2024] Open
Abstract
Microtubules and molecular motors are essential components of the cellular cytoskeleton, driving fundamental processes in vivo, including chromosome segregation and cargo transport. When reconstituted in vitro, these cytoskeletal proteins serve as energy-consuming building blocks to study the self-organization of active matter. Cytoskeletal active gels display rich emergent dynamics, including extensile flows, locally contractile asters, and bulk contraction. However, it is unclear how the protein-protein interaction kinetics set their contractile or extensile nature. Here, we explore the origin of the transition from extensile bundles to contractile asters in a minimal reconstituted system composed of stabilized microtubules, depletant, adenosine 5'-triphosphate (ATP), and clusters of kinesin-1 motors. We show that the microtubule-binding and unbinding kinetics of highly processive motor clusters set their ability to end-accumulate, which can drive polarity sorting of the microtubules and aster formation. We further demonstrate that the microscopic time scale of end-accumulation sets the emergent time scale of aster formation. Finally, we show that biochemical regulation is insufficient to fully explain the transition as generic aligning interactions through depletion, cross-linking, or excluded volume interactions can drive bundle formation despite end-accumulating motors. The extensile-to-contractile transition is well captured by a simple self-assembly model where nematic and polar aligning interactions compete to form either bundles or asters. Starting from a five-dimensional organization phase space, we identify a single control parameter given by the ratio of the different component concentrations that dictates the material-scale organization. Overall, this work shows that the interplay of biochemical and mechanical tuning at the microscopic level controls the robust self-organization of active cytoskeletal materials.
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Affiliation(s)
- Bibi Najma
- Department of Physics, Brandeis University, Waltham, MA02453
| | - Wei-Shao Wei
- Department of Physics, Brandeis University, Waltham, MA02453
| | - Aparna Baskaran
- Department of Physics, Brandeis University, Waltham, MA02453
| | - Peter J. Foster
- Department of Physics, Brandeis University, Waltham, MA02453
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8
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Liebe NL, Mey I, Vuong L, Shikho F, Geil B, Janshoff A, Steinem C. Bioinspired Membrane Interfaces: Controlling Actomyosin Architecture and Contractility. ACS APPLIED MATERIALS & INTERFACES 2023; 15:11586-11598. [PMID: 36848241 PMCID: PMC9999349 DOI: 10.1021/acsami.3c00061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
The creation of biologically inspired artificial lipid bilayers on planar supports provides a unique platform to study membrane-confined processes in a well-controlled setting. At the plasma membrane of mammalian cells, the linkage of the filamentous (F)-actin network is of pivotal importance leading to cell-specific and dynamic F-actin architectures, which are essential for the cell's shape, mechanical resilience, and biological function. These networks are established through the coordinated action of diverse actin-binding proteins and the presence of the plasma membrane. Here, we established phosphatidylinositol-4,5-bisphosphate (PtdIns[4,5]P2)-doped supported planar lipid bilayers to which contractile actomyosin networks were bound via the membrane-actin linker ezrin. This membrane system, amenable to high-resolution fluorescence microscopy, enabled us to analyze the connectivity and contractility of the actomyosin network. We found that the network architecture and dynamics are not only a function of the PtdIns[4,5]P2 concentration but also depend on the presence of negatively charged phosphatidylserine (PS). PS drives the attached network into a regime, where low but physiologically relevant connectivity to the membrane results in strong contractility of the actomyosin network, emphasizing the importance of the lipid composition of the membrane interface.
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Affiliation(s)
- Nils L. Liebe
- Institut
für Organische und Biomolekulare Chemie, Georg-August Universität, Tammannstr. 2, Göttingen 37077, Germany
| | - Ingo Mey
- Institut
für Organische und Biomolekulare Chemie, Georg-August Universität, Tammannstr. 2, Göttingen 37077, Germany
| | - Loan Vuong
- Institut
für Organische und Biomolekulare Chemie, Georg-August Universität, Tammannstr. 2, Göttingen 37077, Germany
| | - Fadi Shikho
- Institut
für Organische und Biomolekulare Chemie, Georg-August Universität, Tammannstr. 2, Göttingen 37077, Germany
| | - Burkhard Geil
- Institut
für Physikalische Chemie, Georg-August
Universität, Tammannstr. 6, Göttingen 37077, Germany
| | - Andreas Janshoff
- Institut
für Physikalische Chemie, Georg-August
Universität, Tammannstr. 6, Göttingen 37077, Germany
| | - Claudia Steinem
- Institut
für Organische und Biomolekulare Chemie, Georg-August Universität, Tammannstr. 2, Göttingen 37077, Germany
- Max-Planck-Institut
für Dynamik und Selbstorganisation, Am Fassberg 17, Göttingen 37077, Germany
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9
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Striebel M, Brauns F, Frey E. Length Regulation Drives Self-Organization in Filament-Motor Mixtures. PHYSICAL REVIEW LETTERS 2022; 129:238102. [PMID: 36563230 DOI: 10.1103/physrevlett.129.238102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 10/10/2022] [Indexed: 06/17/2023]
Abstract
Cytoskeletal networks form complex intracellular structures. Here we investigate a minimal model for filament-motor mixtures in which motors act as depolymerases and thereby regulate filament length. Combining agent-based simulations and hydrodynamic equations, we show that resource-limited length regulation drives the formation of filament clusters despite the absence of mechanical interactions between filaments. Even though the orientation of individual remains fixed, collective filament orientation emerges in the clusters, aligned orthogonal to their interfaces.
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Affiliation(s)
- Moritz Striebel
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 Munich, Germany
| | - Fridtjof Brauns
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 Munich, Germany
| | - Erwin Frey
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, D-80333 Munich, Germany
- Max Planck School Matter to Life, Hofgartenstraße 8, D-80539 Munich, Germany
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10
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Abstract
One of the major challenges of bottom-up synthetic biology is rebuilding a minimal cell division machinery. From a reconstitution perspective, the animal cell division apparatus is mechanically the simplest and therefore attractive to rebuild. An actin-based ring produces contractile force to constrict the membrane. By contrast, microbes and plant cells have a cell wall, so division requires concerted membrane constriction and cell wall synthesis. Furthermore, reconstitution of the actin division machinery helps in understanding the physical and molecular mechanisms of cytokinesis in animal cells and thus our own cells. In this review, we describe the state-of-the-art research on reconstitution of minimal actin-mediated cytokinetic machineries. Based on the conceptual requirements that we obtained from the physics of the shape changes involved in cell division, we propose two major routes for building a minimal actin apparatus capable of division. Importantly, we acknowledge both the passive and active roles that the confining lipid membrane can play in synthetic cytokinesis. We conclude this review by identifying the most pressing challenges for future reconstitution work, thereby laying out a roadmap for building a synthetic cell equipped with a minimal actin division machinery.
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11
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Mondal A, Morrison G. Compression-induced buckling of a semiflexible filament in two and three dimensions. J Chem Phys 2022; 157:104903. [DOI: 10.1063/5.0104910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ability of biomolecules to exert forces on their surroundings or resist compression from the environment is essential in a variety of biologically relevant contexts. For filaments in the low-temperature limit and under a constant compressive force, Euler buckling theory predicts a sudden transition from a compressed to a bent state in these slender rods. In this paper, we use a mean-field theory to show that if a semiflexible chain is compressed at a finite temperature with a fixed end-to-end distance (permitting fluctuations in the compressive forces), it exhibits a continuous phase transition to a buckled state at a critical level of compression. We determine a quantitatively accurate prediction of the transverse position distribution function of the midpoint of the chain that indicates this transition. We find the mean compressive forces are non-monotonic as the extension of the filament varies, consistent with the observation that strongly buckled filaments are less able to bear an external load. We also find that for the fixed extension (isometric) ensemble, the buckling transition does not coincide with the local minimum of the mean force (in contrast to Euler buckling). We also show the theory is highly sensitive to fluctuations in length in two dimensions, and that the buckling transition can still be accurately recovered by accounting for those fluctuations. These predictions may be useful in understanding the behavior of filamentous biomolecules compressed by fluctuating forces, relevant in a variety of biological contexts.
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Affiliation(s)
- Ananya Mondal
- Physics, University of Houston, United States of America
| | - Greg Morrison
- Physics, University of Houston, United States of America
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12
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Costache V, Prigent Garcia S, Plancke CN, Li J, Begnaud S, Suman SK, Reymann AC, Kim T, Robin FB. Rapid assembly of a polar network architecture drives efficient actomyosin contractility. Cell Rep 2022; 39:110868. [PMID: 35649363 PMCID: PMC9210446 DOI: 10.1016/j.celrep.2022.110868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/13/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022] Open
Abstract
Actin network architecture and dynamics play a central role in cell contractility and tissue morphogenesis. RhoA-driven pulsed contractions are a generic mode of actomyosin contractility, but the mechanisms underlying how their specific architecture emerges and how this architecture supports the contractile function of the network remain unclear. Here we show that, during pulsed contractions, the actin network is assembled by two subpopulations of formins: a functionally inactive population (recruited) and formins actively participating in actin filament elongation (elongating). We then show that elongating formins assemble a polar actin network, with barbed ends pointing out of the pulse. Numerical simulations demonstrate that this geometry favors rapid network contraction. Our results show that formins convert a local RhoA activity gradient into a polar network architecture, causing efficient network contractility, underlying the key function of kinetic controls in the assembly and mechanics of cortical network architectures. RhoA-driven actomyosin contractility plays a key role in driving cell and tissue contractility during morphogenesis. Tracking individual formins, Costache et al. show that the network assembled downstream of RhoA displays a polar architecture, barbed ends pointing outward, a feature that supports efficient contractility and force transmission during pulsed contractions.
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Affiliation(s)
- Vlad Costache
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France
| | - Serena Prigent Garcia
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France
| | - Camille N Plancke
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France
| | - Jing Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Simon Begnaud
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France
| | - Shashi Kumar Suman
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France
| | - Anne-Cécile Reymann
- IGBMC, CNRS UMR7104, INSERM U1258, and Université de Strasbourg, Illkirch, France
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
| | - François B Robin
- Sorbonne Université, CNRS, INSERM, Institut de Biologie Paris-Seine IBPS, Laboratoire de Biologie du Développement, Paris, France.
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13
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Ling Z, Li W, Hu J, Li Y, Deng M, Zhang S, Ren X, Wu T, Xia J, Cheng B, Tao X. Targeting CCL2-CCR4 axis suppress cell migration of head and neck squamous cell carcinoma. Cell Death Dis 2022; 13:158. [PMID: 35177591 PMCID: PMC8854715 DOI: 10.1038/s41419-022-04610-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/20/2022] [Accepted: 02/04/2022] [Indexed: 12/13/2022]
Abstract
For head and neck squamous cell carcinoma (HNSCC), the local invasion and distant metastasis represent the predominant causes of mortality. Targeted inhibition of chemokines and their receptors is an ongoing antitumor strategy established on the crucial roles of chemokines in cancer invasion and metastasis. Herein, we showed that C-C motif chemokine ligand 2 (CCL2)- C-C motif chemokine receptor 4 (CCR4) signaling, but not the CCL2- C-C motif chemokine receptor 2 (CCR2) axis, induces the formation of the vav guanine nucleotide exchange factor 2 (Vav2)- Rac family small GTPase 1 (Rac1) complex to activate the phosphorylation of myosin light chain (MLC), which is involved in the regulation of cell motility and cancer metastasis. We identified that targeting CCR4 could effectively interrupt the activation of HNSCC invasion and metastasis induced by CCL2 without the promoting cancer relapse observed during the subsequent withdrawal period. All current findings suggested that CCL2-CCR4-Vav2-Rac1-p-MLC signaling plays an essential role in cell migration and cancer metastasis of HNSCC, and CCR4 may serve as a new potential molecular target for HNSCC therapy.
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Affiliation(s)
- Zihang Ling
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Wei Li
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Jiaqi Hu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Yuanyuan Li
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Miao Deng
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Siyuan Zhang
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Xianyue Ren
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Tong Wu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China
| | - Juan Xia
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China. .,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China.
| | - Bin Cheng
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China. .,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China.
| | - Xiaoan Tao
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, 510055, P. R. China. .,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, Guangdong, 510055, P. R. China.
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14
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Berezney J, Goode BL, Fraden S, Dogic Z. Extensile to contractile transition in active microtubule-actin composites generates layered asters with programmable lifetimes. Proc Natl Acad Sci U S A 2022; 119:e2115895119. [PMID: 35086931 PMCID: PMC8812548 DOI: 10.1073/pnas.2115895119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/21/2021] [Indexed: 12/15/2022] Open
Abstract
We study a reconstituted composite system consisting of an active microtubule network interdigitated with a passive network of entangled F-actin filaments. Increasing the concentration of filamentous actin controls the emergent dynamics, inducing a transition from turbulent-like flows to bulk contractions. At intermediate concentrations, where the active stresses change their symmetry from anisotropic extensile to isotropic contracting, the composite separates into layered asters that coexist with the background turbulent fluid. Contracted onion-like asters have a radially extending microtubule-rich cortex that envelops alternating layers of microtubules and F-actin. These self-regulating structures undergo internal reorganization, which appears to minimize the surface area and maintain the ordered layering, even when undergoing aster merging events. Finally, the layered asters are metastable structures. Their lifetime, which ranges from minutes to hours, is encoded in the material properties of the composite. These results challenge the current models of active matter. They demonstrate self-organized dynamical states and patterns evocative of those observed in the cytoskeleton do not require precise biochemical regulation, but can arise from purely mechanical interactions of actively driven filamentous materials.
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Affiliation(s)
- John Berezney
- Department of Physics, Brandeis University, Waltham, MA 02454
| | - Bruce L Goode
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Seth Fraden
- Department of Physics, Brandeis University, Waltham, MA 02454
| | - Zvonimir Dogic
- Department of Physics, Brandeis University, Waltham, MA 02454;
- Department of Physics, University of California, Santa Barbara, CA 93106
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, CA 93106
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15
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Sobral AF, Chan FY, Norman MJ, Osório DS, Dias AB, Ferreira V, Barbosa DJ, Cheerambathur D, Gassmann R, Belmonte JM, Carvalho AX. Plastin and spectrin cooperate to stabilize the actomyosin cortex during cytokinesis. Curr Biol 2021; 31:5415-5428.e10. [PMID: 34666005 PMCID: PMC8699742 DOI: 10.1016/j.cub.2021.09.055] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/22/2021] [Accepted: 09/21/2021] [Indexed: 11/16/2022]
Abstract
Cytokinesis, the process that partitions the mother cell into two daughter cells, requires the assembly and constriction of an equatorial actomyosin network. Different types of non-motor F-actin crosslinkers localize to the network, but their functional contribution remains poorly understood. Here, we describe a synergy between the small rigid crosslinker plastin and the large flexible crosslinker spectrin in the C. elegans one-cell embryo. In contrast to single inhibitions, co-inhibition of plastin and the βH-spectrin (SMA-1) results in cytokinesis failure due to progressive disorganization and eventual collapse of the equatorial actomyosin network. Cortical localization dynamics of non-muscle myosin II in co-inhibited embryos mimic those observed after drug-induced F-actin depolymerization, suggesting that the combined action of plastin and spectrin stabilizes F-actin in the contractile ring. An in silico model predicts that spectrin is more efficient than plastin at stabilizing the ring and that ring formation is relatively insensitive to βH-spectrin length, which is confirmed in vivo with a sma-1 mutant that lacks 11 of its 29 spectrin repeats. Our findings provide the first evidence that spectrin contributes to cytokinesis and highlight the importance of crosslinker interplay for actomyosin network integrity.
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Affiliation(s)
- Ana Filipa Sobral
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Fung-Yi Chan
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Michael J Norman
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC 27695, USA
| | - Daniel S Osório
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana Beatriz Dias
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Vanessa Ferreira
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Daniel J Barbosa
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Dhanya Cheerambathur
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Reto Gassmann
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Julio Monti Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC 27695, USA; Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC 27695, USA
| | - Ana Xavier Carvalho
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
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16
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Veenvliet JV, Lenne PF, Turner DA, Nachman I, Trivedi V. Sculpting with stem cells: how models of embryo development take shape. Development 2021; 148:dev192914. [PMID: 34908102 PMCID: PMC8722391 DOI: 10.1242/dev.192914] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During embryogenesis, organisms acquire their shape given boundary conditions that impose geometrical, mechanical and biochemical constraints. A detailed integrative understanding how these morphogenetic information modules pattern and shape the mammalian embryo is still lacking, mostly owing to the inaccessibility of the embryo in vivo for direct observation and manipulation. These impediments are circumvented by the developmental engineering of embryo-like structures (stembryos) from pluripotent stem cells that are easy to access, track, manipulate and scale. Here, we explain how unlocking distinct levels of embryo-like architecture through controlled modulations of the cellular environment enables the identification of minimal sets of mechanical and biochemical inputs necessary to pattern and shape the mammalian embryo. We detail how this can be complemented with precise measurements and manipulations of tissue biochemistry, mechanics and geometry across spatial and temporal scales to provide insights into the mechanochemical feedback loops governing embryo morphogenesis. Finally, we discuss how, even in the absence of active manipulations, stembryos display intrinsic phenotypic variability that can be leveraged to define the constraints that ensure reproducible morphogenesis in vivo.
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Affiliation(s)
- Jesse V. Veenvliet
- Stembryogenesis Lab, Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
- Department of Developmental Genetics, Max Planck Institute for Molecular Genetics, Ihnestrasse 63-73, 14195 Berlin, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Pierre-François Lenne
- Aix Marseille University, CNRS, IBDM, Turing Center for Living Systems, 13288, Marseille, France
| | - David A. Turner
- Institute of Life Course and Medical Sciences, William Henry Duncan Building, University of Liverpool, Liverpool, L7 8TX, UK
| | - Iftach Nachman
- School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Vikas Trivedi
- European Molecular Biology Laboratories (EMBL), Barcelona, 08003, Spain
- EMBL Heidelberg, Developmental Biology Unit, 69117, Heidelberg, Germany
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17
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Schmidt A, Li L, Lv Z, Yan S, Großhans J. Dia- and Rok-dependent enrichment of capping proteins in a cortical region. J Cell Sci 2021; 134:272429. [PMID: 34633047 PMCID: PMC8627554 DOI: 10.1242/jcs.258973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 09/24/2021] [Indexed: 01/30/2023] Open
Abstract
Rho signaling with its major targets the formin Dia, Rho kinase (Rok) and non-muscle myosin II (MyoII, encoded by zip in flies) control turnover, amount and contractility of actomyosin. Much less investigated has been a potential function for the distribution of F-actin plus and minus ends. In syncytial Drosophila embryos, Rho1 signaling is high between actin caps, i.e. the cortical intercap region. Capping protein binds to free plus ends of F-actin to prevent elongation of the filament. Capping protein has served as a marker to visualize the distribution of F-actin plus ends in cells and in vitro. In the present study, we probed the distribution of plus ends with capping protein in syncytial Drosophila embryos. We found that capping proteins are specifically enriched in the intercap region similar to Dia and MyoII but distinct from overall F-actin. The intercap enrichment of Capping protein was impaired in dia mutants and embryos, in which Rok and MyoII activation was inhibited. Our observations reveal that Dia and Rok-MyoII control Capping protein enrichment and support a model that Dia and Rok-MyoII control the organization of cortical actin cytoskeleton downstream of Rho1 signaling. This article has an associated First Person interview with the first authors of the paper. Summary: Plus ends of actin filaments are enriched at cortical regions rich in Rho signaling in syncytial Drosophila embryos depending on the actin regulator Dia and Rho kinase.
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Affiliation(s)
- Anja Schmidt
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Long Li
- Department of Biology/FB17, Philipps University, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
| | - Zhiyi Lv
- Department of Biology/FB17, Philipps University, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
| | - Shuling Yan
- Department of Biology/FB17, Philipps University, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
| | - Jörg Großhans
- Department of Biology/FB17, Philipps University, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
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18
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Bhide S, Gombalova D, Mönke G, Stegmaier J, Zinchenko V, Kreshuk A, Belmonte JM, Leptin M. Mechanical competition alters the cellular interpretation of an endogenous genetic program. J Cell Biol 2021; 220:212605. [PMID: 34449835 PMCID: PMC8406609 DOI: 10.1083/jcb.202104107] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 07/26/2021] [Accepted: 07/30/2021] [Indexed: 12/16/2022] Open
Abstract
The intrinsic genetic program of a cell is not sufficient to explain all of the cell's activities. External mechanical stimuli are increasingly recognized as determinants of cell behavior. In the epithelial folding event that constitutes the beginning of gastrulation in Drosophila, the genetic program of the future mesoderm leads to the establishment of a contractile actomyosin network that triggers apical constriction of cells and thereby tissue folding. However, some cells do not constrict but instead stretch, even though they share the same genetic program as their constricting neighbors. We show here that tissue-wide interactions force these cells to expand even when an otherwise sufficient amount of apical, active actomyosin is present. Models based on contractile forces and linear stress-strain responses do not reproduce experimental observations, but simulations in which cells behave as ductile materials with nonlinear mechanical properties do. Our models show that this behavior is a general emergent property of actomyosin networks in a supracellular context, in accordance with our experimental observations of actin reorganization within stretching cells.
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Affiliation(s)
- Sourabh Bhide
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for Joint PhD Degree between European Molecular Biology Laboratory and Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Denisa Gombalova
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for Joint PhD Degree between European Molecular Biology Laboratory and Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Gregor Mönke
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Johannes Stegmaier
- Institute of Imaging and Computer Vision, Rheinisch-Westfälische Technische Hochschule Aachen University, Aachen, Germany
| | - Valentyna Zinchenko
- Collaboration for Joint PhD Degree between European Molecular Biology Laboratory and Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anna Kreshuk
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Julio M Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC.,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Maria Leptin
- Director's Research Unit, European Molecular Biology Laboratory, Heidelberg, Germany.,European Molecular Biology Organization, Heidelberg, Germany
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19
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Protein friction and filament bending facilitate contraction of disordered actomyosin networks. Biophys J 2021; 120:4029-4040. [PMID: 34390686 DOI: 10.1016/j.bpj.2021.08.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/21/2021] [Accepted: 08/06/2021] [Indexed: 12/23/2022] Open
Abstract
We use mathematical modeling and computation to investigate how protein friction facilitates contraction of disordered actomyosin networks. We simulate two-dimensional networks using an agent-based model, consisting of a system of force-balance equations for myosin motor proteins and semiflexible actin filaments. A major advantage of our approach is that it enables direct calculation of the network stress tensor, which provides a quantitative measure of contractility. Exploiting this, we use repeated simulations of disordered networks to confirm that both protein friction and actin filament bending are required for contraction. We then use simulations of elementary two-filament systems to show that filament bending flexibility can facilitate contraction on the microscopic scale. Finally, we show that actin filament turnover is necessary to sustain contraction and prevent filament aggregation. Simulations with and without turnover also exhibit contractile pulses. However, these pulses are aperiodic, suggesting that periodic pulsation can only arise because of additional regulatory mechanisms or more complex mechanical behavior.
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20
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CYK-1/Formin activation in cortical RhoA signaling centers promotes organismal left-right symmetry breaking. Proc Natl Acad Sci U S A 2021; 118:2021814118. [PMID: 33972425 PMCID: PMC8157923 DOI: 10.1073/pnas.2021814118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Proper left-right symmetry breaking is essential for animal development, and in many cases, this process is actomyosin-dependent. In Caenorhabditis elegans embryos active torque generation in the actomyosin layer promotes left-right symmetry breaking by driving chiral counterrotating cortical flows. While both Formins and Myosins have been implicated in left-right symmetry breaking and both can rotate actin filaments in vitro, it remains unclear whether active torques in the actomyosin cortex are generated by Formins, Myosins, or both. We combined the strength of C. elegans genetics with quantitative imaging and thin film, chiral active fluid theory to show that, while Non-Muscle Myosin II activity drives cortical actomyosin flows, it is permissive for chiral counterrotation and dispensable for chiral symmetry breaking of cortical flows. Instead, we find that CYK-1/Formin activation in RhoA foci is instructive for chiral counterrotation and promotes in-plane, active torque generation in the actomyosin cortex. Notably, we observe that artificially generated large active RhoA patches undergo rotations with consistent handedness in a CYK-1/Formin-dependent manner. Altogether, we conclude that CYK-1/Formin-dependent active torque generation facilitates chiral symmetry breaking of actomyosin flows and drives organismal left-right symmetry breaking in the nematode worm.
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21
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Lamson AR, Moore JM, Fang F, Glaser MA, Shelley MJ, Betterton MD. Comparison of explicit and mean-field models of cytoskeletal filaments with crosslinking motors. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:45. [PMID: 33779863 PMCID: PMC8220871 DOI: 10.1140/epje/s10189-021-00042-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 02/20/2021] [Indexed: 05/17/2023]
Abstract
In cells, cytoskeletal filament networks are responsible for cell movement, growth, and division. Filaments in the cytoskeleton are driven and organized by crosslinking molecular motors. In reconstituted cytoskeletal systems, motor activity is responsible for far-from-equilibrium phenomena such as active stress, self-organized flow, and spontaneous nematic defect generation. How microscopic interactions between motors and filaments lead to larger-scale dynamics remains incompletely understood. To build from motor-filament interactions to predict bulk behavior of cytoskeletal systems, more computationally efficient techniques for modeling motor-filament interactions are needed. Here, we derive a coarse-graining hierarchy of explicit and continuum models for crosslinking motors that bind to and walk on filament pairs. We compare the steady-state motor distribution and motor-induced filament motion for the different models and analyze their computational cost. All three models agree well in the limit of fast motor binding kinetics. Evolving a truncated moment expansion of motor density speeds the computation by [Formula: see text]-[Formula: see text] compared to the explicit or continuous-density simulations, suggesting an approach for more efficient simulation of large networks. These tools facilitate further study of motor-filament networks on micrometer to millimeter length scales.
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Affiliation(s)
- Adam R Lamson
- Department of Physics, University of Colorado Boulder, Boulder, USA.
| | - Jeffrey M Moore
- Department of Physics, University of Colorado Boulder, Boulder, USA
| | - Fang Fang
- Courant Institute, New York University, New York, USA
| | - Matthew A Glaser
- Department of Physics, University of Colorado Boulder, Boulder, USA
| | - Michael J Shelley
- Courant Institute, New York University, New York, USA
- Center for Computational Biology, Flatiron Institute, New York, USA
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22
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Bleicher P, Nast-Kolb T, Sciortino A, de la Trobe YA, Pokrant T, Faix J, Bausch AR. Intra-bundle contractions enable extensile properties of active actin networks. Sci Rep 2021; 11:2677. [PMID: 33514794 PMCID: PMC7846802 DOI: 10.1038/s41598-021-81601-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/05/2021] [Indexed: 12/27/2022] Open
Abstract
The cellular cortex is a dynamic and contractile actomyosin network modulated by actin-binding proteins. We reconstituted a minimal cortex adhered to a model cell membrane mimicking two processes mediated by the motor protein myosin: contractility and high turnover of actin monomers. Myosin reorganized these networks by extensile intra‑bundle contractions leading to an altered growth mechanism. Hereby, stress within tethered bundles induced nicking of filaments followed by repair via incorporation of free monomers. This mechanism was able to break the symmetry of the previously disordered network resulting in the generation of extensile clusters, reminiscent of structures found within cells.
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Affiliation(s)
- P Bleicher
- Physik-Department, Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany.
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany.
| | - T Nast-Kolb
- Physik-Department, Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany
| | - A Sciortino
- Physik-Department, Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany
| | - Y A de la Trobe
- Physik-Department, Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany
| | - T Pokrant
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - J Faix
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Hannover, Germany
| | - A R Bausch
- Physik-Department, Lehrstuhl für Biophysik E27, Technische Universität München, Garching, Germany.
- Center for Protein Assemblies (CPA), Ernst-Otto-Fischer Str. 8, 85747, Garching, Germany.
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23
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Leite J, Chan FY, Osório DS, Saramago J, Sobral AF, Silva AM, Gassmann R, Carvalho AX. Equatorial Non-muscle Myosin II and Plastin Cooperate to Align and Compact F-actin Bundles in the Cytokinetic Ring. Front Cell Dev Biol 2020; 8:573393. [PMID: 33102479 PMCID: PMC7546906 DOI: 10.3389/fcell.2020.573393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/03/2020] [Indexed: 12/17/2022] Open
Abstract
Cytokinesis is the last step of cell division that physically partitions the mother cell into two daughter cells. Cytokinesis requires the assembly and constriction of a contractile ring, a circumferential array of filamentous actin (F-actin), non-muscle myosin II motors (myosin), and actin-binding proteins that forms at the cell equator. Cytokinesis is accompanied by long-range cortical flows from regions of relaxation toward regions of compression. In the C. elegans one-cell embryo, it has been suggested that anterior-directed cortical flows are the main driver of contractile ring assembly. Here, we use embryos co-expressing motor-dead and wild-type myosin to show that cortical flows can be severely reduced without major effects on contractile ring assembly and timely completion of cytokinesis. Fluorescence recovery after photobleaching in the ingressing furrow reveals that myosin recruitment kinetics are also unaffected by the absence of cortical flows. We find that myosin cooperates with the F-actin crosslinker plastin to align and compact F-actin bundles at the cell equator, and that this cross-talk is essential for cytokinesis. Our results thus argue against the idea that cortical flows are a major determinant of contractile ring assembly. Instead, we propose that contractile ring assembly requires localized concerted action of motor-competent myosin and plastin at the cell equator.
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Affiliation(s)
- Joana Leite
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Daniel S Osório
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Joana Saramago
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana F Sobral
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana M Silva
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Reto Gassmann
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
| | - Ana X Carvalho
- Cytoskeletal Dynamics Lab, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Cytoskeletal Dynamics Lab, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal
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24
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Jahnke K, Weiss M, Weber C, Platzman I, Göpfrich K, Spatz JP. Engineering Light-Responsive Contractile Actomyosin Networks with DNA Nanotechnology. ACTA ACUST UNITED AC 2020; 4:e2000102. [PMID: 32696544 DOI: 10.1002/adbi.202000102] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 01/01/2023]
Abstract
External control and precise manipulation is key for the bottom-up engineering of complex synthetic cells. Minimal actomyosin networks have been reconstituted into synthetic cells; however, their light-triggered symmetry breaking contraction has not yet been demonstrated. Here, light-activated directional contractility of a minimal synthetic actomyosin network inside microfluidic cell-sized compartments is engineered. Actin filaments, heavy-meromyosin-coated beads, and caged ATP are co-encapsulated into water-in-oil droplets. ATP is released upon illumination, leading to a myosin-generated force which results in a motion of the beads along the filaments and hence a contraction of the network. Symmetry breaking is achieved using DNA nanotechnology to establish a link between the network and the compartment periphery. It is demonstrated that the DNA-linked actin filaments contract to one side of the compartment forming actin asters and quantify the dynamics of this process. This work exemplifies that an engineering approach to bottom-up synthetic biology, combining biological and artificial elements, can circumvent challenges related to active multi-component systems and thereby greatly enrich the complexity of synthetic cellular systems.
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Affiliation(s)
- Kevin Jahnke
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Department of Physics and Astronomy, Heidelberg University, Heidelberg, D 69120, Germany
| | - Marian Weiss
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld, Heidelberg, D 69120, Germany
| | - Cornelia Weber
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld, Heidelberg, D 69120, Germany
| | - Ilia Platzman
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld, Heidelberg, D 69120, Germany
| | - Kerstin Göpfrich
- Biophysical Engineering Group, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Department of Physics and Astronomy, Heidelberg University, Heidelberg, D 69120, Germany
| | - Joachim P Spatz
- Department of Cellular Biophysics, Max Planck Institute for Medical Research, Jahnstraße 29, Heidelberg, D 69120, Germany.,Institute for Molecular Systems Engineering (IMSE), Heidelberg University, Im Neuenheimer Feld, Heidelberg, D 69120, Germany.,Max Planck School Matter to Life, Jahnstraße 29, Heidelberg, D 69120, Germany
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25
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Schroer CFE, Baldauf L, van Buren L, Wassenaar TA, Melo MN, Koenderink GH, Marrink SJ. Charge-dependent interactions of monomeric and filamentous actin with lipid bilayers. Proc Natl Acad Sci U S A 2020; 117:5861-5872. [PMID: 32123101 PMCID: PMC7084070 DOI: 10.1073/pnas.1914884117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The cytoskeletal protein actin polymerizes into filaments that are essential for the mechanical stability of mammalian cells. In vitro experiments showed that direct interactions between actin filaments and lipid bilayers are possible and that the net charge of the bilayer as well as the presence of divalent ions in the buffer play an important role. In vivo, colocalization of actin filaments and divalent ions are suppressed, and cells rely on linker proteins to connect the plasma membrane to the actin network. Little is known, however, about why this is the case and what microscopic interactions are important. A deeper understanding is highly beneficial, first, to obtain understanding in the biological design of cells and, second, as a possible basis for the building of artificial cortices for the stabilization of synthetic cells. Here, we report the results of coarse-grained molecular dynamics simulations of monomeric and filamentous actin in the vicinity of differently charged lipid bilayers. We observe that charges on the lipid head groups strongly determine the ability of actin to adsorb to the bilayer. The inclusion of divalent ions leads to a reversal of the binding affinity. Our in silico results are validated experimentally by reconstitution assays with actin on lipid bilayer membranes and provide a molecular-level understanding of the actin-membrane interaction.
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Affiliation(s)
- Carsten F E Schroer
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Lucia Baldauf
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Lennard van Buren
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Tsjerk A Wassenaar
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica, New University of Lisbon, 2780-157, Oeiras, Portugal
| | - Gijsje H Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands;
- Living Matter Department, AMOLF, 1098 XG Amsterdam, The Netherlands
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands;
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG, Groningen, The Netherlands
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26
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Lenz M. Reversal of contractility as a signature of self-organization in cytoskeletal bundles. eLife 2020; 9:51751. [PMID: 32149609 PMCID: PMC7082124 DOI: 10.7554/elife.51751] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 03/05/2020] [Indexed: 12/13/2022] Open
Abstract
Bundles of cytoskeletal filaments and molecular motors generate motion in living cells, and have internal structures ranging from very organized to apparently disordered. The mechanisms powering the disordered structures are debated, and existing models predominantly predict that they are contractile. We reexamine this prediction through a theoretical treatment of the interplay between three well-characterized internal dynamical processes in cytoskeletal bundles: filament assembly and disassembly, the attachement-detachment dynamics of motors and that of crosslinking proteins. The resulting self-organization is easily understood in terms of motor and crosslink localization, and allows for an extensive control of the active bundle mechanics, including reversals of the filaments’ apparent velocities and the possibility of generating extension instead of contraction. This reversal mirrors some recent experimental observations, and provides a robust criterion to experimentally elucidate the underpinnings of both actomyosin activity and the dynamics of microtubule/motor assemblies in vitro as well as in diverse intracellular structures ranging from contractile bundles to the mitotic spindle.
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Affiliation(s)
- Martin Lenz
- Université Paris-Saclay, CNRS, LPTMS, Orsay, France.,PMMH, CNRS, ESPCI Paris, PSL University, Sorbonne Université, Université de Paris, Paris, France
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27
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Jung W, Tabatabai AP, Thomas JJ, Tabei SMA, Murrell MP, Kim T. Dynamic motions of molecular motors in the actin cytoskeleton. Cytoskeleton (Hoboken) 2019; 76:517-531. [PMID: 31758841 DOI: 10.1002/cm.21582] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 11/14/2019] [Accepted: 11/19/2019] [Indexed: 12/23/2022]
Abstract
During intracellular transport, cellular cargos, such as organelles, vesicles, and proteins, are transported within cells. Intracellular transport plays an important role in diverse cellular functions. Molecular motors walking on the cytoskeleton facilitate active intracellular transport, which is more efficient than diffusion-based passive transport. Active transport driven by kinesin and dynein walking on microtubules has been studied well during recent decades. However, mechanisms of active transport occurring in disorganized actin networks via myosin motors remain elusive. To provide physiologically relevant insights, we probed motions of myosin motors in actin networks under various conditions using our well-established computational model that rigorously accounts for the mechanical and dynamical behaviors of the actin cytoskeleton. We demonstrated that myosin motions can be confined due to three different reasons in the absence of F-actin turnover. We verified mechanisms of motor stalling using in vitro reconstituted actomyosin networks. We also found that with F-actin turnover, motors consistently move for a long time without significant confinement. Our study sheds light on the importance of F-actin turnover for effective active transport in the actin cytoskeleton.
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Affiliation(s)
- Wonyeong Jung
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana
| | - A Pasha Tabatabai
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut.,Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut
| | - Jacob J Thomas
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana
| | - S M Ali Tabei
- Department of Physics, University of Northern Iowa, 215 Begeman Hall, Cedar Falls, Iowa
| | - Michael P Murrell
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, Connecticut.,Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, Connecticut.,Department of Physics, Yale University. 217 Prospect Street, New Haven, Connecticut
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, Indiana
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28
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Network Contractility During Cytokinesis-from Molecular to Global Views. Biomolecules 2019; 9:biom9050194. [PMID: 31109067 PMCID: PMC6572417 DOI: 10.3390/biom9050194] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 12/28/2022] Open
Abstract
Cytokinesis is the last stage of cell division, which partitions the mother cell into two daughter cells. It requires the assembly and constriction of a contractile ring that consists of a filamentous contractile network of actin and myosin. Network contractility depends on network architecture, level of connectivity and myosin motor activity, but how exactly is the contractile ring network organized or interconnected and how much it depends on motor activity remains unclear. Moreover, the contractile ring is not an isolated entity; rather, it is integrated into the surrounding cortex. Therefore, the mechanical properties of the cell cortex and cortical behaviors are expected to impact contractile ring functioning. Due to the complexity of the process, experimental approaches have been coupled to theoretical modeling in order to advance its global understanding. While earlier coarse-grained descriptions attempted to provide an integrated view of the process, recent models have mostly focused on understanding the behavior of an isolated contractile ring. Here we provide an overview of the organization and dynamics of the actomyosin network during cytokinesis and discuss existing theoretical models in light of cortical behaviors and experimental evidence from several systems. Our view on what is missing in current models and should be tested in the future is provided.
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29
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Mulla Y, Wierenga H, Alkemade C, Ten Wolde PR, Koenderink GH. Frustrated binding of biopolymer crosslinkers. SOFT MATTER 2019; 15:3036-3042. [PMID: 30900710 DOI: 10.1039/c8sm02429d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Transiently crosslinked actin filament networks allow cells to combine elastic rigidity with the ability to deform viscoelastically. Theoretical models of semiflexible polymer networks predict that the crosslinker unbinding rate governs the timescale beyond which viscoelastic flow occurs. However a direct comparison between network and crosslinker dynamics is lacking. Here we measure the network's stress relaxation timescale using rheology and the lifetime of bound crosslinkers using fluorescence recovery after photobleaching (FRAP). Intriguingly, we observe that the crosslinker unbinding rate measured by FRAP is more than an order of magnitude slower than the rate measured by rheology. We rationalize this difference with a three-state model where crosslinkers are bound to either 0, 1 or 2 filaments, which allows us to extract crosslinker transition rates that are otherwise difficult to access. We find that the unbinding rate of singly bound crosslinkers is nearly two orders of magnitude slower than for doubly bound ones. We attribute the increased unbinding rate of doubly bound crosslinkers to the high stiffness of biopolymers, which frustrates crosslinker binding.
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Affiliation(s)
- Yuval Mulla
- Living Matter Department, AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
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30
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Ravichandran A, Duman Ö, Hoore M, Saggiorato G, Vliegenthart GA, Auth T, Gompper G. Chronology of motor-mediated microtubule streaming. eLife 2019; 8:e39694. [PMID: 30601119 PMCID: PMC6338466 DOI: 10.7554/elife.39694] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/28/2018] [Indexed: 12/19/2022] Open
Abstract
We introduce a filament-based simulation model for coarse-grained, effective motor-mediated interaction between microtubule pairs to study the time-scales that compose cytoplasmic streaming. We characterise microtubule dynamics in two-dimensional systems by chronologically arranging five distinct processes of varying duration that make up streaming, from microtubule pairs to collective dynamics. The structures found were polarity sorted due to the propulsion of antialigned microtubules. This also gave rise to the formation of large polar-aligned domains, and streaming at the domain boundaries. Correlation functions, mean squared displacements, and velocity distributions reveal a cascade of processes ultimately leading to microtubule streaming and advection, spanning multiple microtubule lengths. The characteristic times for the processes extend over three orders of magnitude from fast single-microtubule processes to slow collective processes. Our approach can be used to directly test the importance of molecular components, such as motors and crosslinking proteins between microtubules, on the collective dynamics at cellular scale.
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Affiliation(s)
- Arvind Ravichandran
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Özer Duman
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Masoud Hoore
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Guglielmo Saggiorato
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Gerard A Vliegenthart
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Thorsten Auth
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
| | - Gerhard Gompper
- Theoretical Soft Matter and Biophysics, Institute of Complex Systems and Institute for Advanced SimulationForschungszentrum JülichJülichGermany
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