1
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Cichos F, Xia T, Yang H, Zijlstra P. The ever-expanding optics of single-molecules and nanoparticles. J Chem Phys 2024; 161:010401. [PMID: 38949895 DOI: 10.1063/5.0221680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2024] [Accepted: 06/10/2024] [Indexed: 07/03/2024] Open
Affiliation(s)
- F Cichos
- Peter Debye Institute for Soft Matter Physics, Leipzig University, Leipzig, Germany
| | - T Xia
- Institute for Immunology, School of Medicine, Tsinghua University, Beijing, China
| | - H Yang
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - P Zijlstra
- Department of Applied Physics and Science Education, Eindhoven University of Technology (TU/e), Eindhoven, The Netherlands
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2
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Vos BE, Muenker TM, Betz T. Characterizing intracellular mechanics via optical tweezers-based microrheology. Curr Opin Cell Biol 2024; 88:102374. [PMID: 38824902 DOI: 10.1016/j.ceb.2024.102374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 04/24/2024] [Accepted: 05/03/2024] [Indexed: 06/04/2024]
Abstract
Intracellular organization is a highly regulated homeostatic state maintained to ensure eukaryotic cells' correct and efficient functioning. Thanks to decades of research, vast knowledge of the proteins involved in intracellular transport and organization has been acquired. However, how these influence and potentially regulate the intracellular mechanical properties of the cell is largely unknown. There is a deep knowledge gap between the understanding of cortical mechanics, which is accessible by a series of experimental tools, and the intracellular situation that has been largely neglected due to the difficulty of performing intracellular mechanics measurements. Recently, tools required for such quantitative and localized analysis of intracellular mechanics have been introduced. Here, we review how these approaches and the resulting viscoelastic models lead the way to a full mechanical description of the cytoplasm, which is instrumental for a quantitative characterization of the intracellular life of cells.
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Affiliation(s)
- Bart E Vos
- Third Institute of Physics, Georg August University, Göttingen, Germany
| | - Till M Muenker
- Third Institute of Physics, Georg August University, Göttingen, Germany
| | - Timo Betz
- Third Institute of Physics, Georg August University, Göttingen, Germany; Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), Georg August University, Göttingen, Germany.
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3
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Desroches Altamirano C, Kang MK, Jordan MA, Borianne T, Dilmen I, Gnädig M, von Appen A, Honigmann A, Franzmann TM, Alberti S. eIF4F is a thermo-sensing regulatory node in the translational heat shock response. Mol Cell 2024; 84:1727-1741.e12. [PMID: 38547866 DOI: 10.1016/j.molcel.2024.02.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 12/18/2023] [Accepted: 02/29/2024] [Indexed: 05/05/2024]
Abstract
Heat-shocked cells prioritize the translation of heat shock (HS) mRNAs, but the underlying mechanism is unclear. We report that HS in budding yeast induces the disassembly of the eIF4F complex, where eIF4G and eIF4E assemble into translationally arrested mRNA ribonucleoprotein particles (mRNPs) and HS granules (HSGs), whereas eIF4A promotes HS translation. Using in vitro reconstitution biochemistry, we show that a conformational rearrangement of the thermo-sensing eIF4A-binding domain of eIF4G dissociates eIF4A and promotes the assembly with mRNA into HS-mRNPs, which recruit additional translation factors, including Pab1p and eIF4E, to form multi-component condensates. Using extracts and cellular experiments, we demonstrate that HS-mRNPs and condensates repress the translation of associated mRNA and deplete translation factors that are required for housekeeping translation, whereas HS mRNAs can be efficiently translated by eIF4A. We conclude that the eIF4F complex is a thermo-sensing node that regulates translation during HS.
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Affiliation(s)
- Christine Desroches Altamirano
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Moo-Koo Kang
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Mareike A Jordan
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Tom Borianne
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Irem Dilmen
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Maren Gnädig
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Alexander von Appen
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Alf Honigmann
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Titus M Franzmann
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany
| | - Simon Alberti
- Biotechnology Center (BIOTEC), Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Tatzberg 47/49, 01307 Dresden, Germany.
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4
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Borne V, Weiss M. Robust spatiotemporal organization of mitotic events in mechanically perturbed C. elegans embryos. Biophys J 2024:S0006-3495(24)00243-1. [PMID: 38576160 DOI: 10.1016/j.bpj.2024.03.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/22/2024] [Accepted: 03/29/2024] [Indexed: 04/06/2024] Open
Abstract
Early embryogenesis of the nematode Caenorhabditis elegans progresses in an autonomous fashion within a protective chitin eggshell. Cell-division timing and the subsequent mechanically guided positioning of cells is virtually invariant between individuals, especially before gastrulation. Here, we have challenged this stereotypical developmental program in early stages by mechanically perturbing the embryo without breaking its eggshell. Compressing embryos to about two-thirds of their unperturbed diameter only resulted in markedly slower cell divisions. In contrast, compressing embryos to half of their native diameter frequently resulted in a loss of cytokinesis, yielding a non-natural syncytium that still allowed for multiple divisions of nuclei. Although the orientation of mitotic axes was strongly altered in the syncytium, key features of division timing and spatial arrangement of nuclei remained surprisingly similar to those of unperturbed embryos in the first few division cycles. This suggests that few, very robust mechanisms provide a basic and resilient program for safeguarding the early embryogenesis of C. elegans.
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Affiliation(s)
- Vincent Borne
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, Bayreuth, Germany.
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5
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Erben E, Liao W, Minopoli A, Maghelli N, Lauga E, Kreysing M. Opto-fluidically multiplexed assembly and micro-robotics. LIGHT, SCIENCE & APPLICATIONS 2024; 13:59. [PMID: 38409110 PMCID: PMC10897173 DOI: 10.1038/s41377-024-01406-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 01/11/2024] [Accepted: 01/31/2024] [Indexed: 02/28/2024]
Abstract
Techniques for high-definition micromanipulations, such as optical tweezers, hold substantial interest across a wide range of disciplines. However, their applicability remains constrained by material properties and laser exposure. And while microfluidic manipulations have been suggested as an alternative, their inherent capabilities are limited and further hindered by practical challenges of implementation and control. Here we show that the iterative application of laser-induced, localized flow fields can be used for the relative positioning of multiple micro-particles, irrespectively of their material properties. Compared to the standing theoretical proposal, our method keeps particles mobile, and we show that their precision manipulation is non-linearly accelerated via the multiplexing of temperature stimuli below the heat diffusion limit. The resulting flow fields are topologically rich and mathematically predictable. They represent unprecedented microfluidic control capabilities that are illustrated by the actuation of humanoid micro-robots with up to 30 degrees of freedom, whose motions are sufficiently well-defined to reliably communicate personal characteristics such as gender, happiness and nervousness. Our results constitute high-definition micro-fluidic manipulations with transformative potential for assembly, micro-manufacturing, the life sciences, robotics and opto-hydraulically actuated micro-factories.
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Affiliation(s)
- Elena Erben
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
- Center for Systems Biology, Dresden, 01307, Germany
- Institute of Biological and Chemical Systems - Biological Information Processing. Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, 76344, Germany
| | - Weida Liao
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, CB3 0WA, UK
| | - Antonio Minopoli
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
- Center for Systems Biology, Dresden, 01307, Germany
| | - Nicola Maghelli
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
- Center for Systems Biology, Dresden, 01307, Germany
| | - Eric Lauga
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, CB3 0WA, UK
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany.
- Center for Systems Biology, Dresden, 01307, Germany.
- Institute of Biological and Chemical Systems - Biological Information Processing. Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, 76344, Germany.
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6
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Seelbinder B, Wagner S, Jain M, Erben E, Klykov S, Stoev ID, Krishnaswamy VR, Kreysing M. Probe-free optical chromatin deformation and measurement of differential mechanical properties in the nucleus. eLife 2024; 13:e76421. [PMID: 38214505 PMCID: PMC10786458 DOI: 10.7554/elife.76421] [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: 12/15/2021] [Accepted: 11/29/2023] [Indexed: 01/13/2024] Open
Abstract
The nucleus is highly organized to facilitate coordinated gene transcription. Measuring the rheological properties of the nucleus and its sub-compartments will be crucial to understand the principles underlying nuclear organization. Here, we show that strongly localized temperature gradients (approaching 1°C/µm) can lead to substantial intra-nuclear chromatin displacements (>1 µm), while nuclear area and lamina shape remain unaffected. Using particle image velocimetry (PIV), intra-nuclear displacement fields can be calculated and converted into spatio-temporally resolved maps of various strain components. Using this approach, we show that chromatin displacements are highly reversible, indicating that elastic contributions are dominant in maintaining nuclear organization on the time scale of seconds. In genetically inverted nuclei, centrally compacted heterochromatin displays high resistance to deformation, giving a rigid, solid-like appearance. Correlating spatially resolved strain maps with fluorescent reporters in conventional interphase nuclei reveals that various nuclear compartments possess distinct mechanical identities. Surprisingly, both densely and loosely packed chromatin showed high resistance to deformation, compared to medium dense chromatin. Equally, nucleoli display particularly high resistance and strong local anchoring to heterochromatin. Our results establish how localized temperature gradients can be used to drive nuclear compartments out of mechanical equilibrium to obtain spatial maps of their material responses.
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Affiliation(s)
- Benjamin Seelbinder
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Susan Wagner
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
| | - Manavi Jain
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Elena Erben
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Sergei Klykov
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | - Iliya Dimitrov Stoev
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
| | | | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and GeneticsDresdenGermany
- Centre for Systems BiologyDresdenGermany
- Institute of Biological and Chemical Systems-Biological Information Processing, Karlsruhe Institute of TechnologyEggenstein-LeopoldshafenGermany
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7
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Bhatnagar A, Nestler M, Gross P, Kramar M, Leaver M, Voigt A, Grill SW. Axis convergence in C. elegans embryos. Curr Biol 2023; 33:5096-5108.e15. [PMID: 37979577 DOI: 10.1016/j.cub.2023.10.050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/31/2023] [Accepted: 10/25/2023] [Indexed: 11/20/2023]
Abstract
Embryos develop in a surrounding that guides key aspects of their development. For example, the anteroposterior (AP) body axis is always aligned with the geometric long axis of the surrounding eggshell in fruit flies and worms. The mechanisms that ensure convergence of the AP axis with the long axis of the eggshell remain unresolved. We investigate axis convergence in early C. elegans development, where the nascent AP axis, when misaligned, actively re-aligns to converge with the long axis of the egg. We identify two physical mechanisms that underlie axis convergence. First, bulk cytoplasmic flows, driven by actomyosin cortical flows, can directly reposition the AP axis. Second, active forces generated within the pseudocleavage furrow, a transient actomyosin structure similar to a contractile ring, can drive a mechanical re-orientation such that it becomes positioned perpendicular to the long axis of the egg. This in turn ensures AP axis convergence. Numerical simulations, together with experiments that either abolish the pseudocleavage furrow or change the shape of the egg, demonstrate that the pseudocleavage-furrow-dependent mechanism is a major driver of axis convergence. We conclude that active force generation within the actomyosin cortical layer drives axis convergence in the early nematode.
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Affiliation(s)
- Archit Bhatnagar
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrase 108, Dresden 01037, Germany
| | - Michael Nestler
- Institute of Scientific Computing, Technische Universitӓt Dresden, Zellescher Weg 25, Dresden 01217, Germany
| | - Peter Gross
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrase 108, Dresden 01037, Germany; Biotechnology Center (BIOTEC), Technische Universitӓt Dresden, Tatzberg 47/49, Dresden 01307, Germany
| | - Mirna Kramar
- Biotechnology Center (BIOTEC), Technische Universitӓt Dresden, Tatzberg 47/49, Dresden 01307, Germany
| | - Mark Leaver
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrase 108, Dresden 01037, Germany
| | - Axel Voigt
- Institute of Scientific Computing, Technische Universitӓt Dresden, Zellescher Weg 25, Dresden 01217, Germany; Cluster of Excellence Physics of Life, Technische Universitӓt Dresden, Arnoldstrase 18, Dresden 01307, Germany; Center for Systems Biology Dresden, Pfotenhauerstrase 108, Dresden 01037, Germany.
| | - Stephan W Grill
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrase 108, Dresden 01037, Germany; Cluster of Excellence Physics of Life, Technische Universitӓt Dresden, Arnoldstrase 18, Dresden 01307, Germany; Center for Systems Biology Dresden, Pfotenhauerstrase 108, Dresden 01037, Germany.
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8
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Arjona MI, Najafi J, Minc N. Cytoplasm mechanics and cellular organization. Curr Opin Cell Biol 2023; 85:102278. [PMID: 37979412 DOI: 10.1016/j.ceb.2023.102278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 11/20/2023]
Abstract
As cells organize spatially or divide, they translocate many micron-scale organelles in their cytoplasm. These include endomembrane vesicles, nuclei, microtubule asters, mitotic spindles, or chromosomes. Organelle motion is powered by cytoskeleton forces but is opposed by viscoelastic forces imparted by the surrounding crowded cytoplasm medium. These resistive forces associated to cytoplasm physcial properties remain generally underappreciated, yet reach significant values to slow down organelle motion or even limit their displacement by springing them back towards their original position. The cytoplasm may also be itself organized in time and space, being for example stiffer or more fluid at certain locations or during particular cell cycle phases. Thus, cytoplasm mechanics may be viewed as a labile module that contributes to organize cells. We here review emerging methods, mechanisms, and concepts to study cytoplasm mechanical properties and their function in organelle positioning, cellular organization and division.
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Affiliation(s)
- María Isabel Arjona
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France
| | - Javad Najafi
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France
| | - Nicolas Minc
- Université de Paris, CNRS, Institut Jacques Monod, F-75006 Paris, France; Equipe Labellisée LIGUE Contre le Cancer, France.
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9
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Ng K, Hirani N, Bland T, Borrego-Pinto J, Wagner S, Kreysing M, Goehring NW. Cleavage furrow-directed cortical flows bias PAR polarization pathways to link cell polarity to cell division. Curr Biol 2023; 33:4298-4311.e6. [PMID: 37729912 DOI: 10.1016/j.cub.2023.08.076] [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: 01/24/2023] [Revised: 07/13/2023] [Accepted: 08/24/2023] [Indexed: 09/22/2023]
Abstract
During development, the conserved PAR polarity network is continuously redeployed, requiring that it adapt to changing cellular contexts and environmental cues. In the early C. elegans embryo, polarity shifts from being a cell-autonomous process in the zygote to one that must be coordinated between neighbors as the embryo becomes multicellular. Here, we sought to explore how the PAR network adapts to this shift in the highly tractable C. elegans germline P lineage. We find that although P lineage blastomeres exhibit a distinct pattern of polarity emergence compared with the zygote, the underlying mechanochemical processes that drive polarity are largely conserved. However, changes in the symmetry-breaking cues of P lineage blastomeres ensure coordination of their polarity axis with neighboring cells. Specifically, we show that furrow-directed cortical flows associated with cytokinesis of the zygote induce symmetry breaking in the germline blastomere P1 by transporting PAR-3 into the nascent cell contact. This pool of PAR-3 then biases downstream PAR polarization pathways to establish the polarity axis of P1 with respect to the position of its anterior sister, AB. Thus, our data suggest that cytokinesis itself induces symmetry breaking through the advection of polarity proteins by furrow-directed flows. By directly linking cell polarity to cell division, furrow-directed cortical flows could be a general mechanism to ensure proper organization of cell polarity within actively dividing systems.
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Affiliation(s)
- KangBo Ng
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | - Nisha Hirani
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Tom Bland
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK
| | | | - Susan Wagner
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany; Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Nathan W Goehring
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Institute for the Physics of Living Systems, University College London, London WC1E 6BT, UK.
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10
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Chen X, Zhao Y, Zhang Y, Li B, Li Y, Jiang L. Optical Manipulation of Soft Matter. SMALL METHODS 2023:e2301105. [PMID: 37818749 DOI: 10.1002/smtd.202301105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/22/2023] [Indexed: 10/13/2023]
Abstract
Optical manipulation has emerged as a pivotal tool in soft matter research, offering superior applicability, spatiotemporal precision, and manipulation capabilities compared to conventional methods. Here, an overview of the optical mechanisms governing the interaction between light and soft matter materials during manipulation is provided. The distinct characteristics exhibited by various soft matter materials, including liquid crystals, polymers, colloids, amphiphiles, thin liquid films, and biological soft materials are highlighted, and elucidate their fundamental response characteristics to optical manipulation techniques. This knowledge serves as a foundation for designing effective strategies for soft matter manipulation. Moreover, the diverse range of applications and future prospects that arise from the synergistic collaboration between optical manipulation and soft matter materials in emerging fields are explored.
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Affiliation(s)
- Xixi Chen
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Yanan Zhao
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Yao Zhang
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Baojun Li
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Yuchao Li
- Guangdong Provincial Key Laboratory of Nanophotonic Manipulation, Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Lingxiang Jiang
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, China
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11
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Nakul U, Roy S, Nalupurackal G, Chakraborty S, Siwach P, Goswami J, Edwina P, Bajpai SK, Singh R, Roy B. Studying fluctuating trajectories of optically confined passive tracers inside cells provides familiar active forces. BIOMEDICAL OPTICS EXPRESS 2023; 14:5440. [PMID: 37810271 PMCID: PMC7615170 DOI: 10.1364/boe.499990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/14/2023] [Accepted: 09/05/2023] [Indexed: 10/10/2023]
Abstract
In recent years, there has been a growing interest in studying the trajectories of microparticles inside living cells. Among other things, such studies are useful in understanding the spatio-temporal properties of a cell. In this work, we study the stochastic trajectories of a passive microparticle inside a cell using experiments and theory. Our theory is based on modeling the microparticle inside a cell as an active particle in a viscoelastic medium. The activity is included in our model from an additional stochastic term with non-zero persistence in the Langevin equation describing the dynamics of the microparticle. Using this model, we are able to predict the power spectral density (PSD) measured in the experiment and compute active forces. This caters to the situation where a tracer particle is optically confined and then yields a PSD for positional fluctuations. The low frequency part of the PSD yields information about the active forces that the particle feels. The fit to the model extracts such active force. Thus, we can conclude that trapping the particle does not affect the values of the forces extracted from the active fits if accounted for appropriately by proper theoretical models. In addition, the fit also provides system properties and optical tweezers trap stiffness.
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Affiliation(s)
- Urvashi Nakul
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Srestha Roy
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Gokul Nalupurackal
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Snigdhadev Chakraborty
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Priyanka Siwach
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Jayesh Goswami
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
| | - Privita Edwina
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
- Department of Applied Mechanics, IIT Madras, Chennai 600036, India
| | | | - Rajesh Singh
- Department of Physics, IIT Madras, Chennai 600036, India
| | - Basudev Roy
- Department of Physics, Quantum Centre of Excellence for Diamond and Emergent Materials (QuCenDiEM), IIT Madras, Chennai 600036, India
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12
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Kim Y, Zheng Y. Advancing optothermal manipulation: decoupling temperature and flow fields in quasi-isothermal microscale streaming. LIGHT, SCIENCE & APPLICATIONS 2023; 12:211. [PMID: 37652899 PMCID: PMC10471763 DOI: 10.1038/s41377-023-01246-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
By decoupling temperature and flow fields through symmetry-correlated laser scan sequences, ISO-FLUCS enables quasi-isothermal optofluidic microscale streaming. This technique offers precise control over fluid manipulation while minimizing thermal damage.
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Affiliation(s)
- Youngsun Kim
- Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yuebing Zheng
- Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
- Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
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13
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Lu W, Gelfand VI. Go with the flow - bulk transport by molecular motors. J Cell Sci 2023; 136:jcs260300. [PMID: 36250267 PMCID: PMC10755412 DOI: 10.1242/jcs.260300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cells are the smallest building blocks of all living eukaryotic organisms, usually ranging from a couple of micrometers (for example, platelets) to hundreds of micrometers (for example, neurons and oocytes) in size. In eukaryotic cells that are more than 100 µm in diameter, very often a self-organized large-scale movement of cytoplasmic contents, known as cytoplasmic streaming, occurs to compensate for the physical constraints of large cells. In this Review, we discuss cytoplasmic streaming in multiple cell types and the mechanisms driving this event. We particularly focus on the molecular motors responsible for cytoplasmic movements and the biological roles of cytoplasmic streaming in cells. Finally, we describe bulk intercellular flow that transports cytoplasmic materials to the oocyte from its sister germline cells to drive rapid oocyte growth.
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Affiliation(s)
- Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA
| | - Vladimir I. Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA
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14
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Scott S, Weiss M, Selhuber-Unkel C, Barooji YF, Sabri A, Erler JT, Metzler R, Oddershede LB. Extracting, quantifying, and comparing dynamical and biomechanical properties of living matter through single particle tracking. Phys Chem Chem Phys 2023; 25:1513-1537. [PMID: 36546878 DOI: 10.1039/d2cp01384c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A panoply of new tools for tracking single particles and molecules has led to an explosion of experimental data, leading to novel insights into physical properties of living matter governing cellular development and function, health and disease. In this Perspective, we present tools to investigate the dynamics and mechanics of living systems from the molecular to cellular scale via single-particle techniques. In particular, we focus on methods to measure, interpret, and analyse complex data sets that are associated with forces, materials properties, transport, and emergent organisation phenomena within biological and soft-matter systems. Current approaches, challenges, and existing solutions in the associated fields are outlined in order to support the growing community of researchers at the interface of physics and the life sciences. Each section focuses not only on the general physical principles and the potential for understanding living matter, but also on details of practical data extraction and analysis, discussing limitations, interpretation, and comparison across different experimental realisations and theoretical frameworks. Particularly relevant results are introduced as examples. While this Perspective describes living matter from a physical perspective, highlighting experimental and theoretical physics techniques relevant for such systems, it is also meant to serve as a solid starting point for researchers in the life sciences interested in the implementation of biophysical methods.
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Affiliation(s)
- Shane Scott
- Institute of Physiology, Kiel University, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Christine Selhuber-Unkel
- Institute for Molecular Systems Engineering, Heidelberg University, D-69120 Heidelberg, Germany.,Max Planck School Matter to Life, Jahnstraße 29, D-69120 Heidelberg, Germany
| | - Younes F Barooji
- Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen, Denmark.
| | - Adal Sabri
- Experimental Physics I, University of Bayreuth, Universitätsstr. 30, D-95447 Bayreuth, Germany
| | - Janine T Erler
- BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark.
| | - Ralf Metzler
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Str. 24/25, D-14476 Potsdam, Germany.,Asia Pacific Center for Theoretical Physics, Pohang 37673, Republic of Korea
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15
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Mitrea DM, Mittasch M, Gomes BF, Klein IA, Murcko MA. Modulating biomolecular condensates: a novel approach to drug discovery. Nat Rev Drug Discov 2022; 21:841-862. [PMID: 35974095 PMCID: PMC9380678 DOI: 10.1038/s41573-022-00505-4] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2022] [Indexed: 12/12/2022]
Abstract
In the past decade, membraneless assemblies known as biomolecular condensates have been reported to play key roles in many cellular functions by compartmentalizing specific proteins and nucleic acids in subcellular environments with distinct properties. Furthermore, growing evidence supports the view that biomolecular condensates often form by phase separation, in which a single-phase system demixes into a two-phase system consisting of a condensed phase and a dilute phase of particular biomolecules. Emerging understanding of condensate function in normal and aberrant cellular states, and of the mechanisms of condensate formation, is providing new insights into human disease and revealing novel therapeutic opportunities. In this Perspective, we propose that such insights could enable a previously unexplored drug discovery approach based on identifying condensate-modifying therapeutics (c-mods), and we discuss the strategies, techniques and challenges involved.
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16
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Bagnat M, Daga B, Di Talia S. Morphogenetic Roles of Hydrostatic Pressure in Animal Development. Annu Rev Cell Dev Biol 2022; 38:375-394. [PMID: 35804476 PMCID: PMC9675319 DOI: 10.1146/annurev-cellbio-120320-033250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During organismal development, organs and systems are built following a genetic blueprint that produces structures capable of performing specific physiological functions. Interestingly, we have learned that the physiological activities of developing tissues also contribute to their own morphogenesis. Specifically, physiological activities such as fluid secretion and cell contractility generate hydrostatic pressure that can act as a morphogenetic force. Here, we first review the role of hydrostatic pressure in tube formation during animal development and discuss mathematical models of lumen formation. We then illustrate specific roles of the notochord as a hydrostatic scaffold in anterior-posterior axis development in chordates. Finally, we cover some examples of how fluid flows influence morphogenetic processes in other developmental contexts. Understanding how fluid forces act during development will be key for uncovering the self-organizing principles that control morphogenesis.
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Affiliation(s)
- Michel Bagnat
- Department of Cell Biology, Duke University, Durham, North Carolina, USA;
| | - Bijoy Daga
- Department of Cell Biology, Duke University, Durham, North Carolina, USA;
| | - Stefano Di Talia
- Department of Cell Biology, Duke University, Durham, North Carolina, USA;
- Department of Orthopaedic Surgery, Duke University, Durham, North Carolina, USA
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17
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Chen X, Wu T, Huang D, Zhou J, Zhou F, Tu M, Zhang Y, Li B, Li Y, Jiang L. Optothermally Programmable Liquids with Spatiotemporal Precision and Functional Complexity. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2205563. [PMID: 35918709 DOI: 10.1002/adma.202205563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/24/2022] [Indexed: 06/15/2023]
Abstract
Due to the intrinsic lack of spatial order and self-supported shape, liquids are often incompatible with precision manufacturing/processing and are potentially limited for advanced functionality. Herein, an optothermal strategy is developed to fully command phase-separated liquids with unprecedented spatiotemporal addressability. Specifically, a laser is focused onto an Au film to create a hot spot that locally demixes a temperature-responsive solution to produce a single optothermal droplet. Spatial precision is assured by the well-defined thermal field and temporal accuracy guaranteed by the fast heating and response rate. Time-multiplexed laser foci are deployed to engineer the thermal landscape as desired, which in turn dictates the formation/dissolution, positioning, shaping, and dynamic reconfiguration of the phase-separated liquids. Further, laser foci are programmed to orchestrate the liquid patterns in a time-continuous manner to produce liquid animations on the microscale with high fidelity. While focused lasers are routinely used to manipulate solid particles or to microfabricate solid materials, the current strategy embraces the merits of liquids and features functional complexity in information encryption, payload transportation, and reaction localization. The strategy is further applicable in scenarios such as subcellular organization of biomolecular condensates and programmable modulation of non-equilibrium systems.
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Affiliation(s)
- Xixi Chen
- Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Tianli Wu
- Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Danmin Huang
- College of Chemistry and Materials Science, Jinan University, Guangzhou, 510632, China
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, China
| | - Jiajia Zhou
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Fengxiang Zhou
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, China
| | - Mei Tu
- College of Chemistry and Materials Science, Jinan University, Guangzhou, 510632, China
| | - Yao Zhang
- Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Baojun Li
- Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Yuchao Li
- Institute of Nanophotonics, Jinan University, Guangzhou, 511443, China
| | - Lingxiang Jiang
- South China Advanced Institute for Soft Matter Science and Technology, School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, China
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18
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Abstract
Some dividing cells sense their shape by becoming polarized along their long axis. Cell polarity is controlled in part by polarity proteins, like Rho GTPases, cycling between active membrane-bound forms and inactive cytosolic forms, modeled as a "wave-pinning" reaction-diffusion process. Does shape sensing emerge from wave pinning? We show that wave pinning senses the cell's long axis. Simulating wave pinning on a curved surface, we find that high-activity domains migrate to peaks and troughs of the surface. For smooth surfaces, a simple rule of minimizing the domain perimeter while keeping its area fixed predicts the final position of the domain and its shape. However, when we introduce roughness to our surfaces, shape sensing can be disrupted, and high-activity domains can become localized to locations other than the global peaks and valleys of the surface. On rough surfaces, the domains of the wave-pinning model are more robust in finding the peaks and troughs than the minimization rule, although both can become trapped in steady states away from the peaks and valleys. We can control the robustness of shape sensing by altering the Rho GTPase diffusivity and the domain size. We also find that the shape-sensing properties of cell polarity models can explain how domains localize to curved regions of deformed cells. Our results help to understand the factors that allow cells to sense their shape-and the limits that membrane roughness can place on this process.
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19
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Hauck N, Beck T, Cojoc G, Schlüßler R, Ahmed S, Raguzin I, Mayer M, Schubert J, Müller P, Guck J, Thiele J. PNIPAAm microgels with defined network architecture as temperature sensors in optical stretchers. MATERIALS ADVANCES 2022; 3:6179-6190. [PMID: 35979502 PMCID: PMC9342673 DOI: 10.1039/d2ma00296e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/10/2022] [Indexed: 06/15/2023]
Abstract
Stretching individual living cells with light is a standard method to assess their mechanical properties. Yet, heat introduced by the laser light of optical stretchers may unwittingly change the mechanical properties of cells therein. To estimate the temperature induced by an optical trap, we introduce cell-sized, elastic poly(N-isopropylacrylamide) (PNIPAAm) microgels that relate temperature changes to hydrogel swelling. For their usage as a standardized calibration tool, we analyze the effect of free-radical chain-growth gelation (FCG) and polymer-analogous photogelation (PAG) on hydrogel network heterogeneity, micromechanics, and temperature response by Brillouin microscopy and optical diffraction tomography. Using a combination of tailor-made PNIPAAm macromers, PAG, and microfluidic processing, we obtain microgels with homogeneous network architecture. With that, we expand the capability of standardized microgels in calibrating and validating cell mechanics analysis, not only considering cell and microgel elasticity but also providing stimuli-responsiveness to consider dynamic changes that cells may undergo during characterization.
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Affiliation(s)
- Nicolas Hauck
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics D-01069 Dresden Germany
| | - Timon Beck
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden D-01307 Dresden Germany
- Max Planck Institute for the Science of Light Staudtstraße 2 D-91058 Erlangen Germany
| | - Gheorghe Cojoc
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden D-01307 Dresden Germany
| | - Raimund Schlüßler
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden D-01307 Dresden Germany
| | - Saeed Ahmed
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden D-01307 Dresden Germany
| | - Ivan Raguzin
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics D-01069 Dresden Germany
| | - Martin Mayer
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics D-01069 Dresden Germany
| | - Jonas Schubert
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics D-01069 Dresden Germany
| | - Paul Müller
- Max Planck Institute for the Science of Light Staudtstraße 2 D-91058 Erlangen Germany
| | - Jochen Guck
- Center for Molecular and Cellular Bioengineering, Biotechnology Center, Technische Universität Dresden D-01307 Dresden Germany
- Max Planck Institute for the Science of Light Staudtstraße 2 D-91058 Erlangen Germany
| | - Julian Thiele
- Leibniz-Institut für Polymerforschung Dresden e.V., Institute of Physical Chemistry and Polymer Physics D-01069 Dresden Germany
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20
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A particle size threshold governs diffusion and segregation of PAR-3 during cell polarization. Cell Rep 2022; 39:110652. [PMID: 35417695 PMCID: PMC9093022 DOI: 10.1016/j.celrep.2022.110652] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 12/14/2021] [Accepted: 03/17/2022] [Indexed: 11/23/2022] Open
Abstract
The actomyosin cortex regulates the localization and function of proteins at the plasma membrane. Here, we study how membrane binding, cortical movements, and diffusion determine membrane protein distribution. In Caenorhabditis elegans zygotes, actomyosin flows transport PAR polarity proteins to establish the anterior-posterior axis. Oligomerization of a key scaffold protein, PAR-3, is required for polarization. PAR-3 oligomers are a heterogeneous population of many different sizes, and it remains unclear how oligomer size affects PAR-3 segregation. To address this question, we engineered PAR-3 to defined sizes. We report that PAR-3 trimers are necessary and sufficient for PAR-3 function during polarization and later embryo development. Quantitative analysis of PAR-3 diffusion shows that a threshold size of three subunits allows PAR-3 clusters to stably bind the membrane, where they are corralled and transported by the actomyosin cortex. Our study provides a quantitative model for size-dependent protein transportation of peripheral membrane proteins by cortical flow. The actomyosin cytoskeleton is a major regulator of cellular organization. Chang and Dickinson develop protein-engineering and particle-tracking tools to study how clustered membrane-bound proteins are transported by actomyosin contractions in vivo. Data-driven modeling reveals how membrane binding, diffusion, and collisions with F-actin contribute to protein movement.
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21
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Zablotsky DY, Mezulis A, Blums E, Maiorov MM. Optothermal grid activation of microflow with magnetic nanoparticle thermophoresis for microfluidics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2022; 380:20200310. [PMID: 34974722 DOI: 10.1098/rsta.2020.0310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 03/24/2021] [Indexed: 06/14/2023]
Abstract
We report focused light-induced activation of intense magnetic microconvection mediated by suspended magnetic nanoparticles in microscale two-dimensional optothermal grids. Fully anisotropic control of microflow and mass transport fluxes is achieved by engaging the magnetic field along one or the other preferred directions. The effect is based on the recently described thermal diffusion-magnetomechanical coupling in synthetic magnetic nanofluids. We expect that the new phenomenon can be applied as an efficient all-optical mixing strategy in integrated microfluidic devices. This article is part of the theme issue 'Transport phenomena in complex systems (part 2)'.
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Affiliation(s)
- D Y Zablotsky
- University of Latvia, Jelgavas 3, Riga 1004, Latvia
- Synthermion LLC, Deglava 126, Riga 1082, Latvia
| | - A Mezulis
- Institute of Solid State Physics, Kengaraga str. 8, Riga 1063, Latvia
| | - E Blums
- University of Latvia, Jelgavas 3, Riga 1004, Latvia
| | - M M Maiorov
- University of Latvia, Jelgavas 3, Riga 1004, Latvia
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22
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Charge-density reduction promotes ribozyme activity in RNA–peptide coacervates via RNA fluidization and magnesium partitioning. Nat Chem 2022; 14:407-416. [PMID: 35165426 PMCID: PMC8979813 DOI: 10.1038/s41557-022-00890-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/05/2022] [Indexed: 12/14/2022]
Abstract
It has long been proposed that phase-separated compartments can provide a basis for the formation of cellular precursors in prebiotic environments. However, we know very little about the properties of coacervates formed from simple peptides, their compatibility with ribozymes or their functional significance. Here we assess the conditions under which functional ribozymes form coacervates with simple peptides. We find coacervation to be most robust when transitioning from long homopeptides to shorter, more pre-biologically plausible heteropeptides. We mechanistically show that these RNA–peptide coacervates display peptide-dependent material properties and cofactor concentrations. We find that the interspacing of cationic and neutral amino acids increases RNA mobility, and we use isothermal calorimetry to reveal sequence-dependent Mg2+ partitioning, two critical factors that together enable ribozyme activity. Our results establish how peptides of limited length, homogeneity and charge density facilitate the compartmentalization of active ribozymes into non-gelating, magnesium-rich coacervates, a scenario that could be applicable to cellular precursors with peptide-dependent functional phenotypes. ![]()
Phase-separated compartments have long been proposed as precursors to cellular life. Now, it has been shown that RNA–peptide protocells are more robust when formed using shorter (rather than longer) peptides, and that peptide sequence determines the functional materials properties of these compartments.
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23
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Biophysical Models of PAR Cluster Transport by Cortical Flow in C. elegans Early Embryogenesis. Bull Math Biol 2022; 84:40. [PMID: 35142872 DOI: 10.1007/s11538-022-00997-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 01/18/2022] [Indexed: 11/02/2022]
Abstract
The clustering of membrane-bound proteins facilitates their transport by cortical actin flow in early Caenorhabditis elegans embryo cell polarity. PAR-3 clustering is critical for this process, yet the biophysical processes that couple protein clusters to cortical flow remain unknown. We develop a discrete, stochastic agent-based model of protein clustering and test four hypothetical models for how clusters may interact with the flow. Results show that the canonical way to assess transport characteristics from single-particle tracking data used thus far in this area, the Péclet number, is insufficient to distinguish these hypotheses and that all models can account for transport characteristics quantified by this measure. However, using this model, we demonstrate that these different cluster-cortex interactions may be distinguished using a different metric, namely the scalar projection of cluster displacement on to the flow displacement vector. Our results thus provide a testable way to use existing single-particle tracking data to test how endogenous protein clusters may interact with the cortical flow to localize during polarity establishment. To facilitate this investigation, we also develop both improved simulation and semi-analytic methodologies to quantify motion summary statistics (e.g., Péclet number and scalar projection) for these stochastic models as a function of biophysical parameters.
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24
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Abstract
Embryonic development hinges on effective coordination of molecular events across space and time. Waves have recently emerged as constituting an ubiquitous mechanism that ensures rapid spreading of regulatory signals across embryos, as well as reliable control of their patterning, namely, for the emergence of body plan structures. In this article, we review a selection of recent quantitative work on signaling waves and present an overview of the theory of waves. Our aim is to provide a succinct yet comprehensive guiding reference for the theoretical frameworks by which signaling waves can arise in embryos. We start, then, from reaction-diffusion systems, both static and time dependent; move to excitable dynamics; and conclude with systems of coupled oscillators. We link these theoretical models to molecular mechanisms recently elucidated for the control of mitotic waves in early embryos, patterning of the vertebrate body axis, micropattern cultures, and bone regeneration. Our goal is to inspire experimental work that will advance theory in development and connect its predictions to quantitative biological observations. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Massimo Vergassola
- Laboratoire de physique de l'École Normale Supérieure, CNRS, PSL Research University, Sorbonne Université, Paris, France; .,Department of Physics, University of California, San Diego, California, USA
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25
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Longhini KM, Glotzer M. Aurora A and cortical flows promote polarization and cytokinesis by inducing asymmetric ECT-2 accumulation. eLife 2022; 11:83992. [PMID: 36533896 PMCID: PMC9799973 DOI: 10.7554/elife.83992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
In the early Caenorhabditis elegans embryo, cell polarization and cytokinesis are interrelated yet distinct processes. Here, we sought to understand a poorly understood aspect of cleavage furrow positioning. Early C. elegans embryos deficient in the cytokinetic regulator centralspindlin form furrows, due to an inhibitory activity that depends on aster positioning relative to the polar cortices. Here, we show polar relaxation is associated with depletion of cortical ECT-2, a RhoGEF, specifically at the posterior cortex. Asymmetric ECT-2 accumulation requires intact centrosomes, Aurora A (AIR-1), and myosin-dependent cortical flows. Within a localization competent ECT-2 fragment, we identified three putative phospho-acceptor sites in the PH domain of ECT-2 that render ECT-2 responsive to inhibition by AIR-1. During both polarization and cytokinesis, our results suggest that centrosomal AIR-1 breaks symmetry via ECT-2 phosphorylation; this local inhibition of ECT-2 is amplified by myosin-driven flows that generate regional ECT-2 asymmetry. Together, these mechanisms cooperate to induce polarized assembly of cortical myosin, contributing to both embryo polarization and cytokinesis.
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Affiliation(s)
- Katrina M Longhini
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicagoUnited States
| | - Michael Glotzer
- Department of Molecular Genetics and Cell Biology, University of ChicagoChicagoUnited States
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26
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Loewith R, Roux A, Pertz O. Chemical-Biology-derived in vivo Sensors: Past, Present, and Future. Chimia (Aarau) 2021; 75:1017-1021. [PMID: 34920770 DOI: 10.2533/chimia.2021.1017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To understand the complex biochemistry and biophysics of biological systems, one needs to be able to monitor local concentrations of molecules, physical properties of macromolecular assemblies and activation status of signaling pathways, in real time, within single cells, and at high spatio-temporal resolution. Here we look at the tools that have been / are being / need to be provided by chemical biology to address these challenges. In particular, we highlight the utility of molecular probes that help to better measure mechanical forces and flux through key signalling pathways. Chemical biology can be used to both build biosensors to visualize, but also actuators to perturb biological processes. An emergent theme is the possibility to multiplex measurements of multiple cellular processes. Advances in microscopy automation now allow us to acquire datasets for 1000's of cells. This produces high dimensional datasets that require computer vision approaches that automate image analysis. The high dimensionality of these datasets are often not immediately accessible to human intuition, and, similarly to 'omics technologies, require statistical approaches for their exploitation. The field of biosensor imaging is therefore experiencing a multidisciplinary transition that will enable it to realize its full potential as a tool to provide a deeper appreciation of cell physiology.
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Affiliation(s)
- Robbie Loewith
- National Centre for Competence in Research in Chemical Biology; Department of Molecular Biology, University of Geneva;,
| | - Aurélien Roux
- National Centre for Competence in Research in Chemical Biology; Department of Biochemistry, University of Geneva; Auré,
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27
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Kusumaatmaja H, May AI, Knorr RL. Intracellular wetting mediates contacts between liquid compartments and membrane-bound organelles. J Cell Biol 2021; 220:212595. [PMID: 34427635 PMCID: PMC8404468 DOI: 10.1083/jcb.202103175] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/14/2021] [Accepted: 08/05/2021] [Indexed: 12/29/2022] Open
Abstract
Protein-rich droplets, such as stress granules, P-bodies, and the nucleolus, perform diverse and specialized cellular functions. Recent evidence has shown the droplets, which are also known as biomolecular condensates or membrane-less compartments, form by phase separation. Many droplets also contact membrane-bound organelles, thereby functioning in development, intracellular degradation, and organization. These underappreciated interactions have major implications for our fundamental understanding of cells. Starting with a brief introduction to wetting phenomena, we summarize recent progress in the emerging field of droplet-membrane contact. We describe the physical mechanism of droplet-membrane interactions, discuss how these interactions remodel droplets and membranes, and introduce "membrane scaffolding" by liquids as a novel reshaping mechanism, thereby demonstrating that droplet-membrane interactions are elastic wetting phenomena. "Membrane-less" and "membrane-bound" condensates likely represent distinct wetting states that together link phase separation with mechanosensitivity and explain key structures observed during embryogenesis, during autophagy, and at synapses. We therefore contend that droplet wetting on membranes provides a robust and intricate means of intracellular organization.
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Affiliation(s)
| | - Alexander I May
- Tokyo Tech World Research Hub Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan.,Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Roland L Knorr
- Graduate School and Faculty of Medicine, University of Tokyo, Tokyo, Japan.,Integrative Research Institute for the Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
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28
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Fritsch AW, Diaz-Delgadillo AF, Adame-Arana O, Hoege C, Mittasch M, Kreysing M, Leaver M, Hyman AA, Jülicher F, Weber CA. Local thermodynamics govern formation and dissolution of Caenorhabditis elegans P granule condensates. Proc Natl Acad Sci U S A 2021; 118:e2102772118. [PMID: 34507991 PMCID: PMC8449359 DOI: 10.1073/pnas.2102772118] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2021] [Indexed: 12/31/2022] Open
Abstract
Membraneless compartments, also known as condensates, provide chemically distinct environments and thus spatially organize the cell. A well-studied example of condensates is P granules in the roundworm Caenorhabditis elegans that play an important role in the development of the germline. P granules are RNA-rich protein condensates that share the key properties of liquid droplets such as a spherical shape, the ability to fuse, and fast diffusion of their molecular components. An outstanding question is to what extent phase separation at thermodynamic equilibrium is appropriate to describe the formation of condensates in an active cellular environment. To address this question, we investigate the response of P granule condensates in living cells to temperature changes. We observe that P granules dissolve upon increasing the temperature and recondense upon lowering the temperature in a reversible manner. Strikingly, this temperature response can be captured by in vivo phase diagrams that are well described by a Flory-Huggins model at thermodynamic equilibrium. This finding is surprising due to active processes in a living cell. To address the impact of such active processes on intracellular phase separation, we discuss temperature heterogeneities. We show that, for typical estimates of the density of active processes, temperature represents a well-defined variable and that mesoscopic volume elements are at local thermodynamic equilibrium. Our findings provide strong evidence that P granule assembly and disassembly are governed by phase separation based on local thermal equilibria where the nonequilibrium nature of the cytoplasm is manifested on larger scales.
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Affiliation(s)
- Anatol W Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | | | - Omar Adame-Arana
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Carsten Hoege
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Matthäus Mittasch
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Dewpoint Therapeutics GmbH, 01307 Dresden, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Mark Leaver
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Frank Jülicher
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
- Center for Systems Biology Dresden, 01307 Dresden, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, 01307 Dresden, Germany
| | - Christoph A Weber
- Division Biological Physics, Max Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany;
- Center for Systems Biology Dresden, 01307 Dresden, Germany
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29
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Erben E, Seelbinder B, Stoev ID, Klykov S, Maghelli N, Kreysing M. Feedback-based positioning and diffusion suppression of particles via optical control of thermoviscous flows. OPTICS EXPRESS 2021; 29:30272-30283. [PMID: 34614753 DOI: 10.1364/oe.432935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
The ability to control the position of micron-size particles with high precision using tools such as optical tweezers has led to major advances in fields such as biology, physics and material science. In this paper, we present a novel optical strategy to confine particles in solution with high spatial control using feedback-controlled thermoviscous flows. We show that this technique allows micron-size particles to be positioned and confined with subdiffraction precision (24 nm), effectively suppressing their diffusion. Due to its physical characteristics, our approach might be particular attractive where laser exposure is of concern or materials are inherently incompatible with optical tweezing since it does not rely on contrast in the refractive index.
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30
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Kimura K, Motegi F. Fluid flow dynamics in cellular patterning. Semin Cell Dev Biol 2021; 120:3-9. [PMID: 34274213 DOI: 10.1016/j.semcdb.2021.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 06/24/2021] [Accepted: 07/01/2021] [Indexed: 10/20/2022]
Abstract
The development of complex forms of multicellular organisms depends on the spatial arrangement of cellular architecture and functions. The interior design of the cell is patterned by spatially biased distributions of molecules and biochemical reactions in the cytoplasm and/or on the plasma membrane. In recent years, a dynamic change in the cytoplasmic fluid flow has emerged as a key physical process of driving long-range transport of molecules to particular destinations within the cell. Here, recent experimental advances in the understanding of the generation of the various types of cytoplasmic flows and contributions to intracellular patterning are reviewed with a particular focus on feedback mechanisms between the mechanical properties of fluid flow and biochemical signaling during animal cell polarization.
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Affiliation(s)
- Kenji Kimura
- School of Science and Technology, Kwansei Gakuin University, Japan.
| | - Fumio Motegi
- Instiute for Genetic Medicine, Hokkaido University, Japan; Temasek Lifesciences Laboratory, Singapore; Mechanobiology Institute, National University of Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore.
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31
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Chartier NT, Mukherjee A, Pfanzelter J, Fürthauer S, Larson BT, Fritsch AW, Amini R, Kreysing M, Jülicher F, Grill SW. A hydraulic instability drives the cell death decision in the nematode germline. NATURE PHYSICS 2021; 17:920-925. [PMID: 34777551 PMCID: PMC8548275 DOI: 10.1038/s41567-021-01235-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 03/30/2021] [Indexed: 05/02/2023]
Abstract
Oocytes are large cells that develop into an embryo upon fertilization1. As interconnected germ cells mature into oocytes, some of them grow-typically at the expense of others that undergo cell death2-4. We present evidence that in the nematode Caenorhabditis elegans, this cell-fate decision is mechanical and related to tissue hydraulics. An analysis of germ cell volumes and material fluxes identifies a hydraulic instability that amplifies volume differences and causes some germ cells to grow and others to shrink, a phenomenon that is related to the two-balloon instability5. Shrinking germ cells are extruded and they die, as we demonstrate by artificially reducing germ cell volumes via thermoviscous pumping6. Our work reveals a hydraulic symmetry-breaking transition central to the decision between life and death in the nematode germline.
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Affiliation(s)
| | - Arghyadip Mukherjee
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems (MPI-PKS), Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
| | - Julia Pfanzelter
- Biotechnology Center, TU Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | | | - Ben T. Larson
- Department of Molecular and Cell Biology, University of California, Berkeley, CA USA
- Biophysics Graduate Group, University of California, Berkeley, CA USA
| | - Anatol W. Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Rana Amini
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Cluster of Excellence—Physics of Life, TU Dresden, Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems (MPI-PKS), Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Cluster of Excellence—Physics of Life, TU Dresden, Dresden, Germany
| | - Stephan W. Grill
- Biotechnology Center, TU Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
- Cluster of Excellence—Physics of Life, TU Dresden, Dresden, Germany
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32
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Åberg C, Poolman B. Glass-like characteristics of intracellular motion in human cells. Biophys J 2021; 120:2355-2366. [PMID: 33887228 DOI: 10.1016/j.bpj.2021.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 03/29/2021] [Accepted: 04/09/2021] [Indexed: 10/21/2022] Open
Abstract
The motion in the cytosol of microorganisms such as bacteria and yeast has been observed to undergo a dramatic slowing down upon cell energy depletion. These observations have been interpreted as the motion being "glassy," but whether this notion is useful also for active, motor-protein-driven transport in eukaryotic cells is less clear. Here, we use fluorescence microscopy of beads in human (HeLa) cells to probe the motion of membrane-surrounded structures that are carried along the cytoskeleton by motor proteins. Evaluating several hallmarks of glassy dynamics, we show that at short length scales, the motion is heterogeneous, is nonergodic, is well described by a model for the displacement distribution in glassy systems, and exhibits a decoupling of the exchange and persistence times. Overall, these results suggest that the short length scale behavior of objects that can be transported actively by motor proteins in human cells shares features with the motion in glassy systems.
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Affiliation(s)
- Christoffer Åberg
- Groningen Research Institute of Pharmacy, University of Groningen, Groningen, the Netherlands; Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
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33
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Wang Y, Yang Y, Wang X, Kawazoe N, Yang Y, Chen G. The varied influences of cell adhesion and spreading on gene transfection of mesenchymal stem cells on a micropatterned substrate. Acta Biomater 2021; 125:100-111. [PMID: 33524558 DOI: 10.1016/j.actbio.2021.01.042] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 01/08/2021] [Accepted: 01/26/2021] [Indexed: 12/17/2022]
Abstract
Transmembrane transport of exogenous genes is widely investigated because of high demand for gene therapy. Both gene carriers and cellular conditions can affect gene transfection efficiency. Although cell morphology has been reported to affect cell functions, the influence of cell adhesion area and cell spreading area on the transfection of exogenous genes remains unclear because it is difficult to separate the individual influence of these areas during normal cell culture. In this study, micropatterns were prepared to separately control the adhesion and spreading areas of human bone marrow-derived mesenchymal stem cells (hMSCs). Transfection efficiency of the green fluorescent protein gene to hMSCs cultured on the micropatterns was compared. Cells with a larger adhesion area showed higher transfection efficiency, while cell spreading area hardly affected gene transfection efficiency. Cell adhesion area had dominant influence on gene transfection. Microparticle uptake and BrdU staining showed that the cellular uptake capacity and DNA synthesis activity increased with the increase in cell adhesion area, but were not affected by cell spreading area. The different influence of cell adhesion area and cell spreading area on gene transfection was correlated with their influence on cellular uptake capacity, DNA synthesis activity, focal adhesion formation, cytoskeletal mechanics, and mechanotransduction signal activation. The results suggest that cell adhesion area and cell spreading area had different influence on gene transfection; this finding should provide useful information for the manipulation of cell functions in gene therapy, protein modification, and cell reprogramming. STATEMENT OF SIGNIFICANCE: Cell adhesion and spreading are important morphological factors during the interaction of cells with biomaterial surfaces or interfaces. However, the predominant morphological factor that affects cellular functions such as gene transfection remains unclear. In the present study, special micropatterns were used to precisely control cell adhesion and spreading areas independently. Mesenchymal stem cells cultured on the micropatterns were transfected with the green fluorescent protein gene to compare the different influence of cell adhesion and spreading areas on gene transfection efficiency. Cell adhesion area showed dominant influence on gene transfection, while cell spreading area did not affect gene transfection. The dominant influence of cell adhesion area could be explained by cellular uptake capacity and DNA synthesis activity through the formation of FAs, cytoskeletal mechanics, and YAP/TAZ nuclear localization. The results provide new insights of correlation between cell morphology and cellular functions for designing functional biomaterials.
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34
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Lenne PF, Munro E, Heemskerk I, Warmflash A, Bocanegra-Moreno L, Kishi K, Kicheva A, Long Y, Fruleux A, Boudaoud A, Saunders TE, Caldarelli P, Michaut A, Gros J, Maroudas-Sacks Y, Keren K, Hannezo E, Gartner ZJ, Stormo B, Gladfelter A, Rodrigues A, Shyer A, Minc N, Maître JL, Di Talia S, Khamaisi B, Sprinzak D, Tlili S. Roadmap for the multiscale coupling of biochemical and mechanical signals during development. Phys Biol 2021; 18. [PMID: 33276350 PMCID: PMC8380410 DOI: 10.1088/1478-3975/abd0db] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/04/2020] [Indexed: 12/12/2022]
Abstract
The way in which interactions between mechanics and biochemistry lead to the emergence of complex cell and tissue organization is an old question that has recently attracted renewed interest from biologists, physicists, mathematicians and computer scientists. Rapid advances in optical physics, microscopy and computational image analysis have greatly enhanced our ability to observe and quantify spatiotemporal patterns of signalling, force generation, deformation, and flow in living cells and tissues. Powerful new tools for genetic, biophysical and optogenetic manipulation are allowing us to perturb the underlying machinery that generates these patterns in increasingly sophisticated ways. Rapid advances in theory and computing have made it possible to construct predictive models that describe how cell and tissue organization and dynamics emerge from the local coupling of biochemistry and mechanics. Together, these advances have opened up a wealth of new opportunities to explore how mechanochemical patterning shapes organismal development. In this roadmap, we present a series of forward-looking case studies on mechanochemical patterning in development, written by scientists working at the interface between the physical and biological sciences, and covering a wide range of spatial and temporal scales, organisms, and modes of development. Together, these contributions highlight the many ways in which the dynamic coupling of mechanics and biochemistry shapes biological dynamics: from mechanoenzymes that sense force to tune their activity and motor output, to collectives of cells in tissues that flow and redistribute biochemical signals during development.
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Affiliation(s)
- Pierre-François Lenne
- Aix-Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille, France
| | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, United States of America
| | - Idse Heemskerk
- Department of Cell & Developmental Biology, University of Michigan Medical School, Ann Arbor, MI 48109, United States of America
| | - Aryeh Warmflash
- Department of Biosciences and Bioengineering, Rice University, Houston, TX, 77005, United States of America
| | | | - Kasumi Kishi
- IST Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Anna Kicheva
- IST Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Yuchen Long
- Reproduction et Dévelopement des Plantes, Université de Lyon, École normale supérieure de Lyon, Université Claude Bernard Lyon 1, INRAe, CNRS, 69364 Lyon Cedex 07, France
| | - Antoine Fruleux
- Reproduction et Dévelopement des Plantes, Université de Lyon, École normale supérieure de Lyon, Université Claude Bernard Lyon 1, INRAe, CNRS, 69364 Lyon Cedex 07, France.,LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Arezki Boudaoud
- Reproduction et Dévelopement des Plantes, Université de Lyon, École normale supérieure de Lyon, Université Claude Bernard Lyon 1, INRAe, CNRS, 69364 Lyon Cedex 07, France.,LadHyX, CNRS, Ecole polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau Cedex, France
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, 117411, Singapore
| | - Paolo Caldarelli
- Cellule Pasteur UPMC, Sorbonne Université, rue du Dr Roux, 75015 Paris, France.,Department of Developmental and Stem Cell Biology Institut Pasteur, 75724 Paris, Cedex 15, France.,CNRS UMR3738, 75015 Paris, France
| | - Arthur Michaut
- Department of Developmental and Stem Cell Biology Institut Pasteur, 75724 Paris, Cedex 15, France.,CNRS UMR3738, 75015 Paris, France
| | - Jerome Gros
- Department of Developmental and Stem Cell Biology Institut Pasteur, 75724 Paris, Cedex 15, France.,CNRS UMR3738, 75015 Paris, France
| | - Yonit Maroudas-Sacks
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Kinneret Keren
- Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel.,Network Biology Research Laboratories and The Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Edouard Hannezo
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Zev J Gartner
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 600 16th St. Box 2280, San Francisco, CA 94158, United States of America
| | - Benjamin Stormo
- Department of Biology, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 United States of America
| | - Amy Gladfelter
- Department of Biology, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 United States of America
| | - Alan Rodrigues
- Laboratory of Morphogenesis, The Rockefeller University, 1230 York Avenue, New York, NY 10065, United States of America
| | - Amy Shyer
- Laboratory of Morphogenesis, The Rockefeller University, 1230 York Avenue, New York, NY 10065, United States of America
| | - Nicolas Minc
- Institut Jacques Monod, Université de Paris, CNRS UMR7592, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
| | - Jean-Léon Maître
- Institut Curie, PSL Research University, Sorbonne Université, CNRS UMR3215, INSERM U934, Paris, France
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710, United States of America
| | - Bassma Khamaisi
- School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - David Sprinzak
- School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Sham Tlili
- Aix-Marseille University, CNRS, IBDM, Turing Center for Living Systems, Marseille, France
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35
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Seirin-Lee S. The Role of Cytoplasmic MEX-5/6 Polarity in Asymmetric Cell Division. Bull Math Biol 2021; 83:29. [PMID: 33594535 PMCID: PMC7886744 DOI: 10.1007/s11538-021-00860-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Accepted: 01/14/2021] [Indexed: 11/29/2022]
Abstract
In the process of asymmetric cell division, the mother cell induces polarity in both the membrane and the cytosol by distributing substrates and components asymmetrically. Such polarity formation results from the harmonization of the upstream and downstream polarities between the cell membrane and the cytosol. MEX-5/6 is a well-investigated downstream cytoplasmic protein, which is deeply involved in the membrane polarity of the upstream transmembrane protein PAR in the Caenorhabditis elegans embryo. In contrast to the extensive exploration of membrane PAR polarity, cytoplasmic polarity is poorly understood, and the precise contribution of cytoplasmic polarity to the membrane PAR polarity remains largely unknown. In this study, we explored the interplay between the cytoplasmic MEX-5/6 polarity and the membrane PAR polarity by developing a mathematical model that integrates the dynamics of PAR and MEX-5/6 and reflects the cell geometry. Our investigations show that the downstream cytoplasmic protein MEX-5/6 plays an indispensable role in causing a robust upstream PAR polarity, and the integrated understanding of their interplay, including the effect of the cell geometry, is essential for the study of polarity formation in asymmetric cell division.
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Affiliation(s)
- Sungrim Seirin-Lee
- Department of Mathematics, Department of Mathematical and Life Sciences, Graduate School of Integrated Science for Life, Hiroshima University, Kagamiyama 1-3-1, Hiroshima, 700-0046, Japan.
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36
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Delattre M, Goehring NW. The first steps in the life of a worm: Themes and variations in asymmetric division in C. elegans and other nematodes. Curr Top Dev Biol 2021; 144:269-308. [PMID: 33992156 DOI: 10.1016/bs.ctdb.2020.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Starting with Boveri in the 1870s, microscopic investigation of early embryogenesis in a broad swath of nematode species revealed the central role of asymmetric cell division in embryonic axis specification, blastomere positioning, and cell fate specification. Notably, across the class Chromadorea, a conserved theme emerges-asymmetry is first established in the zygote and specifies its asymmetric division, giving rise to an anterior somatic daughter cell and a posterior germline daughter cell. Beginning in the 1980s, the emergence of Caenorhabditis elegans as a model organism saw the advent of genetic tools that enabled rapid progress in our understanding of the molecular mechanisms underlying asymmetric division, in many cases defining key paradigms that turn out to regulate asymmetric division in a wide range of systems. Yet, the consequence of this focus on C. elegans came at the expense of exploring the extant diversity of developmental variation exhibited across nematode species. Given the resurgent interest in evolutionary studies facilitated in part by new tools, here we revisit the diversity in this asymmetric first division, juxtaposing molecular insight into mechanisms of symmetry-breaking, spindle positioning and fate specification, with a consideration of plasticity and variability within and between species. In the process, we hope to highlight questions of evolutionary forces and molecular variation that may have shaped the extant diversity of developmental mechanisms observed across Nematoda.
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Affiliation(s)
- Marie Delattre
- Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Inserm, UCBL, Lyon, France.
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37
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Shamipour S, Caballero-Mancebo S, Heisenberg CP. Cytoplasm's Got Moves. Dev Cell 2021; 56:213-226. [PMID: 33321104 DOI: 10.1016/j.devcel.2020.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/22/2020] [Accepted: 11/30/2020] [Indexed: 01/01/2023]
Abstract
Cytoplasm is a gel-like crowded environment composed of various macromolecules, organelles, cytoskeletal networks, and cytosol. The structure of the cytoplasm is highly organized and heterogeneous due to the crowding of its constituents and their effective compartmentalization. In such an environment, the diffusive dynamics of the molecules are restricted, an effect that is further amplified by clustering and anchoring of molecules. Despite the crowded nature of the cytoplasm at the microscopic scale, large-scale reorganization of the cytoplasm is essential for important cellular functions, such as cell division and polarization. How such mesoscale reorganization of the cytoplasm is achieved, especially for large cells such as oocytes or syncytial tissues that can span hundreds of micrometers in size, is only beginning to be understood. In this review, we will discuss recent advances in elucidating the molecular, cellular, and biophysical mechanisms by which the cytoskeleton drives cytoplasmic reorganization across different scales, structures, and species.
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Affiliation(s)
- Shayan Shamipour
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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38
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The Actomyosin Cortex of Cells: A Thin Film of Active Matter. J Indian Inst Sci 2021. [DOI: 10.1007/s41745-020-00220-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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39
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Fungal Wound Healing through Instantaneous Protoplasmic Gelation. Curr Biol 2021; 31:271-282.e5. [DOI: 10.1016/j.cub.2020.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/24/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023]
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40
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Mittasch M, Tran VM, Rios MU, Fritsch AW, Enos SJ, Ferreira Gomes B, Bond A, Kreysing M, Woodruff JB. Regulated changes in material properties underlie centrosome disassembly during mitotic exit. J Cell Biol 2020; 219:133724. [PMID: 32050025 PMCID: PMC7147112 DOI: 10.1083/jcb.201912036] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 12/25/2022] Open
Abstract
Centrosomes must resist microtubule-mediated forces for mitotic chromosome segregation. During mitotic exit, however, centrosomes are deformed and fractured by those same forces, which is a key step in centrosome disassembly. How the functional material properties of centrosomes change throughout the cell cycle, and how they are molecularly tuned, remain unknown. Here, we used optically induced flow perturbations to determine the molecular basis of centrosome strength and ductility in C. elegans embryos. We found that both properties declined sharply at anaphase onset, long before natural disassembly. This mechanical transition required PP2A phosphatase and correlated with inactivation of PLK-1 (Polo kinase) and SPD-2 (Cep192). In vitro, PLK-1 and SPD-2 directly protected centrosome scaffolds from force-induced disassembly. Our results suggest that, before anaphase, PLK-1 and SPD-2 respectively confer strength and ductility to the centrosome scaffold so that it can resist microtubule-pulling forces. In anaphase, centrosomes lose PLK-1 and SPD-2 and transition to a weak, brittle state that enables force-mediated centrosome disassembly.
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Affiliation(s)
- Matthäus Mittasch
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Vanna M Tran
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Manolo U Rios
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Anatol W Fritsch
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Stephen J Enos
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Alec Bond
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Moritz Kreysing
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jeffrey B Woodruff
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX
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41
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Woodruff JB. The material state of centrosomes: lattice, liquid, or gel? Curr Opin Struct Biol 2020; 66:139-147. [PMID: 33248427 DOI: 10.1016/j.sbi.2020.10.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 12/25/2022]
Abstract
Centrosomes are micron-scale structures that nucleate microtubule arrays for chromosome segregation and mitotic spindle positioning. For these jobs, centrosomes must be dynamic enough to grow, yet stable enough to resist microtubule-mediated forces. How do centrosomes achieve such seemingly contradictory features? While much is understood about the molecular parts of centrosomes, very little is known about their functional material properties. Two prevalent hypotheses pose that the centrosome is either a liquid droplet or a solid lattice. However, many material states exist between a pure Newtonian liquid and a crystalline solid, and it is not clear where centrosomes lie along this spectrum. Furthermore, broad terms like "liquid" or "solid" do not reveal functional properties like strength, ductility, elasticity, and toughness, which are more relevant to understand how centrosomes resist forces. This review covers recent findings and new rheology techniques that reveal the material characteristics of centrosomes and how they are regulated.
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Affiliation(s)
- Jeffrey B Woodruff
- Department of Cell Biology, Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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42
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A framework for understanding the functions of biomolecular condensates across scales. Nat Rev Mol Cell Biol 2020; 22:215-235. [PMID: 33169001 DOI: 10.1038/s41580-020-00303-z] [Citation(s) in RCA: 391] [Impact Index Per Article: 97.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
Biomolecular condensates are found throughout eukaryotic cells, including in the nucleus, in the cytoplasm and on membranes. They are also implicated in a wide range of cellular functions, organizing molecules that act in processes ranging from RNA metabolism to signalling to gene regulation. Early work in the field focused on identifying condensates and understanding how their physical properties and regulation arise from molecular constituents. Recent years have brought a focus on understanding condensate functions. Studies have revealed functions that span different length scales: from molecular (modulating the rates of chemical reactions) to mesoscale (organizing large structures within cells) to cellular (facilitating localization of cellular materials and homeostatic responses). In this Roadmap, we discuss representative examples of biochemical and cellular functions of biomolecular condensates from the recent literature and organize these functions into a series of non-exclusive classes across the different length scales. We conclude with a discussion of areas of current interest and challenges in the field, and thoughts about how progress may be made to further our understanding of the widespread roles of condensates in cell biology.
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43
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Naganathan S, Oates A. Patterning and mechanics of somite boundaries in zebrafish embryos. Semin Cell Dev Biol 2020; 107:170-178. [DOI: 10.1016/j.semcdb.2020.04.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 03/12/2020] [Accepted: 04/19/2020] [Indexed: 12/12/2022]
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44
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S Mogre S, Brown AI, Koslover EF. Getting around the cell: physical transport in the intracellular world. Phys Biol 2020; 17:061003. [PMID: 32663814 DOI: 10.1088/1478-3975/aba5e5] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eukaryotic cells face the challenging task of transporting a variety of particles through the complex intracellular milieu in order to deliver, distribute, and mix the many components that support cell function. In this review, we explore the biological objectives and physical mechanisms of intracellular transport. Our focus is on cytoplasmic and intra-organelle transport at the whole-cell scale. We outline several key biological functions that depend on physically transporting components across the cell, including the delivery of secreted proteins, support of cell growth and repair, propagation of intracellular signals, establishment of organelle contacts, and spatial organization of metabolic gradients. We then review the three primary physical modes of transport in eukaryotic cells: diffusive motion, motor-driven transport, and advection by cytoplasmic flow. For each mechanism, we identify the main factors that determine speed and directionality. We also highlight the efficiency of each transport mode in fulfilling various key objectives of transport, such as particle mixing, directed delivery, and rapid target search. Taken together, the interplay of diffusion, molecular motors, and flows supports the intracellular transport needs that underlie a broad variety of biological phenomena.
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Affiliation(s)
- Saurabh S Mogre
- Department of Physics, University of California, San Diego, San Diego, California 92093, United States of America
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45
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Gubieda AG, Packer JR, Squires I, Martin J, Rodriguez J. Going with the flow: insights from Caenorhabditis elegans zygote polarization. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190555. [PMID: 32829680 PMCID: PMC7482210 DOI: 10.1098/rstb.2019.0555] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
Abstract
Cell polarity is the asymmetric distribution of cellular components along a defined axis. Polarity relies on complex signalling networks between conserved patterning proteins, including the PAR (partitioning defective) proteins, which become segregated in response to upstream symmetry breaking cues. Although the mechanisms that drive the asymmetric localization of these proteins are dependent upon cell type and context, in many cases the regulation of actomyosin cytoskeleton dynamics is central to the transport, recruitment and/or stabilization of these polarity effectors into defined subcellular domains. The transport or advection of PAR proteins by an actomyosin flow was first observed in the Caenorhabditis elegans zygote more than a decade ago. Since then a multifaceted approach, using molecular methods, high-throughput screens, and biophysical and computational models, has revealed further aspects of this flow and how polarity regulators respond to and modulate it. Here, we review recent findings on the interplay between actomyosin flow and the PAR patterning networks in the polarization of the C. elegans zygote. We also discuss how these discoveries and developed methods are shaping our understanding of other flow-dependent polarizing systems. This article is part of a discussion meeting issue 'Contemporary morphogenesis'.
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Affiliation(s)
| | | | | | | | - Josana Rodriguez
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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46
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Carlini L, Brittingham GP, Holt LJ, Kapoor TM. Microtubules Enhance Mesoscale Effective Diffusivity in the Crowded Metaphase Cytoplasm. Dev Cell 2020; 54:574-582.e4. [PMID: 32818469 PMCID: PMC7685229 DOI: 10.1016/j.devcel.2020.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 06/10/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022]
Abstract
Mesoscale macromolecular complexes and organelles, tens to hundreds of nanometers in size, crowd the eukaryotic cytoplasm. It is therefore unclear how mesoscale particles remain sufficiently mobile to regulate dynamic processes such as cell division. Here, we study mobility across dividing cells that contain densely packed, dynamic microtubules, comprising the metaphase spindle. In dividing human cells, we tracked 40 nm genetically encoded multimeric nanoparticles (GEMs), whose sizes are commensurate with the inter-filament spacing in metaphase spindles. Unexpectedly, the effective diffusivity of GEMs was similar inside the dense metaphase spindle and the surrounding cytoplasm. Eliminating microtubules or perturbing their polymerization dynamics decreased diffusivity by ~30%, suggesting that microtubule polymerization enhances random displacements to amplify diffusive-like motion. Our results suggest that microtubules effectively fluidize the mitotic cytoplasm to equalize mesoscale mobility across a densely packed, dynamic, non-uniform environment, thus spatially maintaining a key biophysical parameter that impacts biochemistry, ranging from metabolism to the nucleation of cytoskeletal filaments.
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Affiliation(s)
- Lina Carlini
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA
| | - Gregory P Brittingham
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - Liam J Holt
- Institute for Systems Genetics, New York University Langone Health, New York, NY 10016, USA
| | - Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, NY 10065, USA.
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47
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Baffou G, Cichos F, Quidant R. Applications and challenges of thermoplasmonics. NATURE MATERIALS 2020; 19:946-958. [PMID: 32807918 DOI: 10.1038/s41563-020-0740-6] [Citation(s) in RCA: 136] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/08/2020] [Indexed: 05/18/2023]
Abstract
Over the past two decades, there has been a growing interest in the use of plasmonic nanoparticles as sources of heat remotely controlled by light, giving rise to the field of thermoplasmonics. The ability to release heat on the nanoscale has already impacted a broad range of research activities, from biomedicine to imaging and catalysis. Thermoplasmonics is now entering an important phase: some applications have engaged in an industrial stage, while others, originally full of promise, experience some difficulty in reaching their potential. Meanwhile, innovative fundamental areas of research are being developed. In this Review, we scrutinize the current research landscape in thermoplasmonics, with a specific focus on its applications and main challenges in many different fields of science, including nanomedicine, cell biology, photothermal and hot-electron chemistry, solar light harvesting, soft matter and nanofluidics.
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Affiliation(s)
- Guillaume Baffou
- Institut Fresnel, CNRS, Aix Marseille University, Ecole Centrale Marseille, Marseille, France.
| | - Frank Cichos
- Molecular Nanophotonics Group, Peter Debye Institute for Soft Matter Physics, Universität Leipzig, Leipzig, Germany.
| | - Romain Quidant
- ICFO - Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, Barcelona, Spain.
- ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
- Nanophotonic Systems Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
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48
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Nazockdast E, Redemann S. Mechanics of the spindle apparatus. Semin Cell Dev Biol 2020; 107:91-102. [PMID: 32747191 DOI: 10.1016/j.semcdb.2020.06.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 06/02/2020] [Accepted: 06/30/2020] [Indexed: 12/01/2022]
Abstract
During mitosis microtubules self-organize to form a bipolar mitotic spindle structure, which positions the sister chromatids on the spindle mid-plane and separates them afterwards. Previous studies have identified many spindle associated proteins. Yet, we do not fully understand how these nanoscopic proteins lead to force generation through interactions of individual microtubules, motor proteins and chromosomes, and how a large number of these local interactions ultimately determine the structure and mechanics of the spindle in micron scale. Here we review the current understanding and open questions related to the structure and mechanics of the mitotic spindle. We then discuss how a combination of electron microscopy and computational modeling can be used to tackle some of these open questions.
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Affiliation(s)
- Ehssan Nazockdast
- Department of Applied Physical Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3250, USA.
| | - Stefanie Redemann
- Center for Membrane and Cell Physiology & Department of Molecular Physiology and Biological Physics, University of Virginia, School of Medicine, Charlottesville, VA, USA.
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49
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Özgüç Ö, Maître JL. Multiscale morphogenesis of the mouse blastocyst by actomyosin contractility. Curr Opin Cell Biol 2020; 66:123-129. [PMID: 32711300 DOI: 10.1016/j.ceb.2020.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 01/31/2023]
Abstract
During preimplantation development, the mouse embryo forms the blastocyst, which consists of a squamous epithelium enveloping a fluid-filled lumen and a cluster of pluripotent cells. The shaping of the blastocyst into its specific architecture is a prerequisite to implantation and further development of the embryo. Recent studies identified the central role of the actomyosin cortex in generating the forces driving the successive steps of blastocyst morphogenesis. As seen in other developing animals, actomyosin functions across spatial scales from the subcellular to the tissue levels. In addition, the slow development of the mouse embryo reveals that actomyosin contractility operates at multiple timescales with periodic cortical waves of contraction every ∼80 s and tissue remodeling over hours.
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Affiliation(s)
- Özge Özgüç
- Institut Curie, 26, rue d'Ulm - 75248 Paris Cedex 05 - France
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50
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Flow Induced Symmetry Breaking in a Conceptual Polarity Model. Cells 2020; 9:cells9061524. [PMID: 32585819 PMCID: PMC7349905 DOI: 10.3390/cells9061524] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/19/2022] Open
Abstract
Important cellular processes, such as cell motility and cell division, are coordinated by cell polarity, which is determined by the non-uniform distribution of certain proteins. Such protein patterns form via an interplay of protein reactions and protein transport. Since Turing’s seminal work, the formation of protein patterns resulting from the interplay between reactions and diffusive transport has been widely studied. Over the last few years, increasing evidence shows that also advective transport, resulting from cytosolic and cortical flows, is present in many cells. However, it remains unclear how and whether these flows contribute to protein-pattern formation. To address this question, we use a minimal model that conserves the total protein mass to characterize the effects of cytosolic flow on pattern formation. Combining a linear stability analysis with numerical simulations, we find that membrane-bound protein patterns propagate against the direction of cytoplasmic flow with a speed that is maximal for intermediate flow speed. We show that the mechanism underlying this pattern propagation relies on a higher protein influx on the upstream side of the pattern compared to the downstream side. Furthermore, we find that cytosolic flow can change the membrane pattern qualitatively from a peak pattern to a mesa pattern. Finally, our study shows that a non-uniform flow profile can induce pattern formation by triggering a regional lateral instability.
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