1
|
Kechagia Z, Eibauer M, Medalia O. Structural determinants of intermediate filament mechanics. Curr Opin Cell Biol 2024; 89:102375. [PMID: 38850681 DOI: 10.1016/j.ceb.2024.102375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/26/2024] [Accepted: 05/03/2024] [Indexed: 06/10/2024]
Abstract
Intermediate filaments (IFs) are integral to the cell cytoskeleton, supporting cellular mechanical stability. Unlike other cytoskeletal components, the detailed structure of assembled IFs has yet to be resolved. This review highlights new insights, linking the complex IF hierarchical assembly to their mechanical properties and impact on cellular functions. While we focus on vimentin IFs, we draw comparisons to keratins, showcasing the distinctive structural and mechanical features that underlie their unique mechanical responses.
Collapse
Affiliation(s)
- Zanetta Kechagia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| | - Matthias Eibauer
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
| |
Collapse
|
2
|
Conboy JP, Istúriz Petitjean I, van der Net A, Koenderink GH. How cytoskeletal crosstalk makes cells move: Bridging cell-free and cell studies. BIOPHYSICS REVIEWS 2024; 5:021307. [PMID: 38840976 PMCID: PMC11151447 DOI: 10.1063/5.0198119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 05/13/2024] [Indexed: 06/07/2024]
Abstract
Cell migration is a fundamental process for life and is highly dependent on the dynamical and mechanical properties of the cytoskeleton. Intensive physical and biochemical crosstalk among actin, microtubules, and intermediate filaments ensures their coordination to facilitate and enable migration. In this review, we discuss the different mechanical aspects that govern cell migration and provide, for each mechanical aspect, a novel perspective by juxtaposing two complementary approaches to the biophysical study of cytoskeletal crosstalk: live-cell studies (often referred to as top-down studies) and cell-free studies (often referred to as bottom-up studies). We summarize the main findings from both experimental approaches, and we provide our perspective on bridging the two perspectives to address the open questions of how cytoskeletal crosstalk governs cell migration and makes cells move.
Collapse
Affiliation(s)
- James P. Conboy
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Irene Istúriz Petitjean
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Anouk van der Net
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Gijsje H. Koenderink
- Department of Bionanoscience, Kavli Institute of Nanoscience Delft, Delft University of Technology, 2629 HZ Delft, The Netherlands
| |
Collapse
|
3
|
Petitjean II, Tran QD, Goutou A, Kabir Z, Wiche G, Leduc C, Koenderink GH. Reconstitution of cytolinker-mediated crosstalk between actin and vimentin. Eur J Cell Biol 2024; 103:151403. [PMID: 38503131 DOI: 10.1016/j.ejcb.2024.151403] [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: 10/27/2023] [Revised: 03/06/2024] [Accepted: 03/06/2024] [Indexed: 03/21/2024] Open
Abstract
Cell shape and motility are determined by the cytoskeleton, an interpenetrating network of actin filaments, microtubules, and intermediate filaments. The biophysical properties of each filament type individually have been studied extensively by cell-free reconstitution. By contrast, the interactions between the three cytoskeletal networks are relatively unexplored. They are coupled via crosslinkers of the plakin family such as plectin. These are challenging proteins for reconstitution because of their giant size and multidomain structure. Here we engineer a recombinant actin-vimentin crosslinker protein called 'ACTIF' that provides a minimal model system for plectin, recapitulating its modular design with actin-binding and intermediate filament-binding domains separated by a coiled-coil linker for dimerisation. We show by fluorescence and electron microscopy that ACTIF has a high binding affinity for vimentin and actin and creates mixed actin-vimentin bundles. Rheology measurements show that ACTIF-mediated crosslinking strongly stiffens actin-vimentin composites. Finally, we demonstrate the modularity of this approach by creating an ACTIF variant with the intermediate filament binding domain of Adenomatous Polyposis Coli. Our protein engineering approach provides a new cell-free system for the biophysical characterization of intermediate filament-binding crosslinkers and for understanding the mechanical synergy between actin and vimentin in mesenchymal cells.
Collapse
Affiliation(s)
- Irene Istúriz Petitjean
- Department of Bionanoscience & Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ, Delft, the Netherlands
| | - Quang D Tran
- CNRS, Institut Jacques Monod, Université Paris Cité, Paris F-75013, France
| | - Angeliki Goutou
- Department of Bionanoscience & Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ, Delft, the Netherlands
| | - Zima Kabir
- Department of Bionanoscience & Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ, Delft, the Netherlands
| | - Gerhard Wiche
- Max Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, Vienna, Austria
| | - Cécile Leduc
- CNRS, Institut Jacques Monod, Université Paris Cité, Paris F-75013, France.
| | - Gijsje H Koenderink
- Department of Bionanoscience & Kavli Institute of Nanoscience, Delft University of Technology, 2629 HZ, Delft, the Netherlands.
| |
Collapse
|
4
|
Lorenz C, Köster S. Multiscale architecture: Mechanics of composite cytoskeletal networks. BIOPHYSICS REVIEWS 2022; 3:031304. [PMID: 38505277 PMCID: PMC10903411 DOI: 10.1063/5.0099405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 07/27/2022] [Indexed: 03/21/2024]
Abstract
Different types of biological cells respond differently to mechanical stresses, and these responses are mainly governed by the cytoskeleton. The main components of this biopolymer network are actin filaments, microtubules, and intermediate filaments, whose mechanical and dynamic properties are highly distinct, thus opening up a large mechanical parameter space. Aside from experiments on whole, living cells, "bottom-up" approaches, utilizing purified, reconstituted protein systems, tremendously help to shed light on the complex mechanics of cytoskeletal networks. Such experiments are relevant in at least three aspects: (i) from a fundamental point of view, cytoskeletal networks provide a perfect model system for polymer physics; (ii) in materials science and "synthetic cell" approaches, one goal is to fully understand properties of cellular materials and reconstitute them in synthetic systems; (iii) many diseases are associated with cell mechanics, so a thorough understanding of the underlying phenomena may help solving pressing biomedical questions. In this review, we discuss the work on networks consisting of one, two, or all three types of filaments, entangled or cross-linked, and consider active elements such as molecular motors and dynamically growing filaments. Interestingly, tuning the interactions among the different filament types results in emergent network properties. We discuss current experimental challenges, such as the comparability of different studies, and recent methodological advances concerning the quantification of attractive forces between filaments and their influence on network mechanics.
Collapse
Affiliation(s)
- C. Lorenz
- Institute for X-Ray Physics, University of Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - S. Köster
- Author to whom correspondence should be addressed:
| |
Collapse
|
5
|
Shen Y, Wu H, Lu PJ, Wang D, Shayegan M, Li H, Shi W, Wang Z, Cai LH, Xia J, Zhang M, Ding R, Herrmann H, Goldman R, MacKintosh FC, Moncho-Jordá A, Weitz DA. Effects of Vimentin Intermediate Filaments on the Structure and Dynamics of In Vitro Multicomponent Interpenetrating Cytoskeletal Networks. PHYSICAL REVIEW LETTERS 2021; 127:108101. [PMID: 34533352 PMCID: PMC10725302 DOI: 10.1103/physrevlett.127.108101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 06/01/2021] [Accepted: 07/30/2021] [Indexed: 05/28/2023]
Abstract
We investigate the rheological properties of interpenetrating networks reconstituted from the main cytoskeletal components: filamentous actin, microtubules, and vimentin intermediate filaments. The elastic modulus is determined largely by actin, with little contribution from either microtubules or vimentin. However, vimentin dramatically impacts the relaxation, with even small amounts significantly increasing the relaxation time of the interpenetrating network. This highly unusual decoupling between dissipation and elasticity may reflect weak attractive interactions between vimentin and actin networks.
Collapse
Affiliation(s)
- Yinan Shen
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Huayin Wu
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Peter J Lu
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Dianzhuo Wang
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Marjan Shayegan
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hui Li
- School of Systems Science, Beijing Normal University, Beijing 100875, China
| | - Weichao Shi
- Key Laboratory of Functional Polymer Materials of the Ministry of Education, Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zizhao Wang
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Li-Heng Cai
- Materials Science and Engineering & Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Jing Xia
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Meng Zhang
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Precision Medicine Institute, The First Affiliated Hospital of Sun Yat-Sen University, Sun Yat-Sen University, Guangzhou 510080, China
| | - Ruihua Ding
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana and Champaign, Illinois 61801, USA
| | - Harald Herrmann
- Division of Cell Biology, German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
- Institute of Neuropathology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Robert Goldman
- Department of Cell and Developmental Biology, Northwestern University, Chicago, Illinois 60611, USA
| | - Fred C MacKintosh
- Department of Chemical and Biomolecular Engineering & Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
| | - Arturo Moncho-Jordá
- Department of Applied Physics & Institute Carlos I for Theoretical and Computational Physics, University of Granada, Granada 18071, Spain
| | - David A Weitz
- Department of Physics & John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA
| |
Collapse
|
6
|
Intermediate Filaments from Tissue Integrity to Single Molecule Mechanics. Cells 2021; 10:cells10081905. [PMID: 34440673 PMCID: PMC8392029 DOI: 10.3390/cells10081905] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 12/22/2022] Open
Abstract
Cytoplasmic intermediate filaments (IFs), which together with actin and microtubules form the cytoskeleton, are composed of a large and diverse family of proteins. Efforts to elucidate the molecular mechanisms responsible for IF-associated diseases increasingly point towards a major contribution of IFs to the cell’s ability to adapt, resist and respond to mechanical challenges. From these observations, which echo the impressive resilience of IFs in vitro, we here discuss the role of IFs as master integrators of cell and tissue mechanics. In this review, we summarize our current understanding of the contribution of IFs to cell and tissue mechanics and explain these results in light of recent in vitro studies that have investigated physical properties of single IFs and IF networks. Finally, we highlight how changes in IF gene expression, network assembly dynamics, and post-translational modifications can tune IF properties to adapt cell and tissue mechanics to changing environments.
Collapse
|
7
|
Elbalasy I, Mollenkopf P, Tutmarc C, Herrmann H, Schnauß J. Keratins determine network stress responsiveness in reconstituted actin-keratin filament systems. SOFT MATTER 2021; 17:3954-3962. [PMID: 33724291 DOI: 10.1039/d0sm02261f] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The cytoskeleton is a major determinant of cell mechanics, and alterations in the central mechanical aspects of cells are observed during many pathological situations. Therefore, it is essential to investigate the interplay between the main filament systems of the cytoskeleton in the form of composite networks. Here, we investigate the role of keratin intermediate filaments (IFs) in network strength by studying in vitro reconstituted actin and keratin 8/18 composite filament networks via bulk shear rheology. We co-polymerized these structural proteins in varying ratios and recorded how their relative content affects the overall mechanical response of the various composites. For relatively small deformations, we found that all composites exhibited an intermediate linear viscoelastic behaviour compared to that of the pure networks. In stark contrast, when larger deformations were imposed the composites displayed increasing strain stiffening behaviour with increasing keratin content. The extent of strain stiffening is much more pronounced than in corresponding experiments performed with vimentin IF as a composite network partner for actin. Our results provide new insights into the mechanical interplay between actin and keratin filaments in which keratin provides reinforcement to actin. This interplay may contribute to the overall integrity of cells. Hence, the high keratin 8/18 content of mechanically stressed simple epithelial cell layers, as found in the lung and the intestine, provides an explanation for their exceptional stability.
Collapse
Affiliation(s)
- Iman Elbalasy
- Peter-Debye Institute for Soft Matter Physics, Leipzig University, 04103 Leipzig, Germany
| | | | | | | | | |
Collapse
|
8
|
Patteson AE, Carroll RJ, Iwamoto DV, Janmey PA. The vimentin cytoskeleton: when polymer physics meets cell biology. Phys Biol 2020; 18:011001. [PMID: 32992303 PMCID: PMC8240483 DOI: 10.1088/1478-3975/abbcc2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The proper functions of tissues depend on the ability of cells to withstand stress and maintain shape. Central to this process is the cytoskeleton, comprised of three polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). IF proteins are among the most abundant cytoskeletal proteins in cells; yet they remain some of the least understood. Their structure and function deviate from those of their cytoskeletal partners, F-actin and microtubules. IF networks show a unique combination of extensibility, flexibility and toughness that confers mechanical resilience to the cell. Vimentin is an IF protein expressed in mesenchymal cells. This review highlights exciting new results on the physical biology of vimentin intermediate filaments and their role in allowing whole cells and tissues to cope with stress.
Collapse
Affiliation(s)
- Alison E Patteson
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Robert J Carroll
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Daniel V Iwamoto
- Institute for Medicine and Engineering, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul A Janmey
- Institute for Medicine and Engineering, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
| |
Collapse
|
9
|
Borin D, Peña B, Taylor MR, Mestroni L, Lapasin R, Sbaizero O. Viscoelastic behavior of cardiomyocytes carrying LMNA mutations. Biorheology 2020; 57:1-14. [DOI: 10.3233/bir-190229] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
| | - Brisa Peña
- University of Colorado Anschutz Medical Campus - Aurora, CO, , USA
| | | | - Luisa Mestroni
- University of Colorado Anschutz Medical Campus - Aurora, CO, , USA
| | | | | |
Collapse
|
10
|
Kwon S, Kim KS. Qualitative analysis of contribution of intracellular skeletal changes to cellular elasticity. Cell Mol Life Sci 2020; 77:1345-1355. [PMID: 31605149 PMCID: PMC11105102 DOI: 10.1007/s00018-019-03328-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/25/2019] [Accepted: 09/30/2019] [Indexed: 01/07/2023]
Abstract
Cells are dynamic structures that continually generate and sustain mechanical forces within their environments. Cells respond to mechanical forces by changing their shape, moving, and differentiating. These reactions are caused by intracellular skeletal changes, which induce changes in cellular mechanical properties such as stiffness, elasticity, viscoelasticity, and adhesiveness. Interdisciplinary research combining molecular biology with physics and mechanical engineering has been conducted to characterize cellular mechanical properties and understand the fundamental mechanisms of mechanotransduction. In this review, we focus on the role of cytoskeletal proteins in cellular mechanics. The specific role of each cytoskeletal protein, including actin, intermediate filaments, and microtubules, on cellular elasticity is summarized along with the effects of interactions between the fibers.
Collapse
Affiliation(s)
- Sangwoo Kwon
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul, 02447, Republic of Korea
| | - Kyung Sook Kim
- Department of Biomedical Engineering, College of Medicine, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul, 02447, Republic of Korea.
| |
Collapse
|
11
|
Broussard JA, Jaiganesh A, Zarkoob H, Conway DE, Dunn AR, Espinosa HD, Janmey PA, Green KJ. Scaling up single-cell mechanics to multicellular tissues - the role of the intermediate filament-desmosome network. J Cell Sci 2020; 133:jcs228031. [PMID: 32179593 PMCID: PMC7097224 DOI: 10.1242/jcs.228031] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cells and tissues sense, respond to and translate mechanical forces into biochemical signals through mechanotransduction, which governs individual cell responses that drive gene expression, metabolic pathways and cell motility, and determines how cells work together in tissues. Mechanotransduction often depends on cytoskeletal networks and their attachment sites that physically couple cells to each other and to the extracellular matrix. One way that cells associate with each other is through Ca2+-dependent adhesion molecules called cadherins, which mediate cell-cell interactions through adherens junctions, thereby anchoring and organizing the cortical actin cytoskeleton. This actin-based network confers dynamic properties to cell sheets and developing organisms. However, these contractile networks do not work alone but in concert with other cytoarchitectural elements, including a diverse network of intermediate filaments. This Review takes a close look at the intermediate filament network and its associated intercellular junctions, desmosomes. We provide evidence that this system not only ensures tissue integrity, but also cooperates with other networks to create more complex tissues with emerging properties in sensing and responding to increasingly stressful environments. We will also draw attention to how defects in intermediate filament and desmosome networks result in both chronic and acquired diseases.
Collapse
Affiliation(s)
- Joshua A Broussard
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| | - Avinash Jaiganesh
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Hoda Zarkoob
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Alexander R Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Horacio D Espinosa
- Department of Mechanical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Paul A Janmey
- Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen J Green
- Departments of Dermatology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL 60611, USA
| |
Collapse
|
12
|
Fitzpatrick R, Michieletto D, Peddireddy KR, Hauer C, Kyrillos C, Gurmessa BJ, Robertson-Anderson RM. Synergistic Interactions Between DNA and Actin Trigger Emergent Viscoelastic Behavior. PHYSICAL REVIEW LETTERS 2018; 121:257801. [PMID: 30608839 DOI: 10.1103/physrevlett.121.257801] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 09/10/2018] [Indexed: 05/12/2023]
Abstract
Composites of flexible and rigid polymers are ubiquitous in biology and industry alike, yet the physical principles determining their mechanical properties are far from understood. Here, we couple force spectroscopy with large-scale Brownian dynamics simulations to elucidate the unique viscoelastic properties of custom-engineered blends of entangled flexible DNA molecules and semiflexible actin filaments. We show that composites exhibit enhanced stress stiffening and prolonged mechanomemory compared to systems of actin or DNA alone, and that these nonlinear features display a surprising nonmonotonic dependence on the fraction of actin in the composite. Simulations reveal that these counterintuitive results arise from synergistic microscale interactions between the two biopolymers. Namely, DNA entropically drives actin filaments to form bundles that stiffen the network but reduce the entanglement density, while a uniform well-connected actin network is required to reinforce the DNA network against yielding and flow. The competition between bundling and connectivity triggers an unexpected stress response that leads equal mass DNA-actin composites to exhibit the most pronounced stress stiffening and the most long-lived entanglements.
Collapse
Affiliation(s)
- Robert Fitzpatrick
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | - Davide Michieletto
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Karthik R Peddireddy
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | - Cole Hauer
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | - Carl Kyrillos
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | - Bekele J Gurmessa
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, USA
| | | |
Collapse
|
13
|
Golde T, Huster C, Glaser M, Händler T, Herrmann H, Käs JA, Schnauß J. Glassy dynamics in composite biopolymer networks. SOFT MATTER 2018; 14:7970-7978. [PMID: 30176034 PMCID: PMC6183213 DOI: 10.1039/c8sm01061g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/31/2018] [Indexed: 05/05/2023]
Abstract
The cytoskeleton is a highly interconnected meshwork of strongly coupled subsystems providing mechanical stability as well as dynamic functions to cells. To elucidate the underlying biophysical principles, it is central to investigate not only one distinct functional subsystem but rather their interplay as composite biopolymeric structures. Two of the key cytoskeletal elements are actin and vimentin filaments. Here, we show that composite networks reconstituted from actin and vimentin can be described by a superposition of two non-interacting scaffolds. Arising effects are demonstrated in a scale-spanning frame connecting single filament dynamics to macro-rheological network properties. The acquired results of the linear and non-linear bulk mechanics can be captured within an inelastic glassy wormlike chain model. In contrast to previous studies, we find no emergent effects in these composite networks. Thus, our study paves the way to predict the mechanics of the cytoskeleton based on the properties of its single structural components.
Collapse
Affiliation(s)
- Tom Golde
- Peter Debye Institute for Soft Matter Physics
, University of Leipzig
,
04103 Leipzig
, Germany
.
| | - Constantin Huster
- Institute for Theoretical Physics
, University of Leipzig
,
04103 Leipzig
, Germany
| | - Martin Glaser
- Peter Debye Institute for Soft Matter Physics
, University of Leipzig
,
04103 Leipzig
, Germany
.
- Fraunhofer Institute for Cell Therapy and Immunology
,
04103 Leipzig
, Germany
| | - Tina Händler
- Peter Debye Institute for Soft Matter Physics
, University of Leipzig
,
04103 Leipzig
, Germany
.
- Fraunhofer Institute for Cell Therapy and Immunology
,
04103 Leipzig
, Germany
| | - Harald Herrmann
- Molecular Genetics
, German Cancer Research Center
,
69120 Heidelberg
, Germany
- Department of Neuropathology
, University Hospital Erlangen
,
91054
, Erlangen
, Germany
| | - Josef A. Käs
- Peter Debye Institute for Soft Matter Physics
, University of Leipzig
,
04103 Leipzig
, Germany
.
| | - Jörg Schnauß
- Peter Debye Institute for Soft Matter Physics
, University of Leipzig
,
04103 Leipzig
, Germany
.
- Fraunhofer Institute for Cell Therapy and Immunology
,
04103 Leipzig
, Germany
| |
Collapse
|
14
|
Ricketts SN, Ross JL, Robertson-Anderson RM. Co-Entangled Actin-Microtubule Composites Exhibit Tunable Stiffness and Power-Law Stress Relaxation. Biophys J 2018; 115:1055-1067. [PMID: 30177441 PMCID: PMC6139891 DOI: 10.1016/j.bpj.2018.08.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 07/19/2018] [Accepted: 08/06/2018] [Indexed: 12/25/2022] Open
Abstract
We use optical tweezers microrheology and fluorescence microscopy to characterize the nonlinear mesoscale mechanics and mobility of in vitro co-entangled actin-microtubule composites. We create a suite of randomly oriented, well-mixed networks of actin and microtubules by co-polymerizing varying ratios of actin and tubulin in situ. To perturb each composite far from equilibrium, we use optical tweezers to displace an embedded microsphere a distance greater than the lengths of the filaments at a speed much faster than their intrinsic relaxation rates. We simultaneously measure the force the filaments exert on the bead and the subsequent force relaxation. We find that the presence of a large fraction of microtubules (>0.7) is needed to substantially increase the measured force, which is accompanied by large heterogeneities in force response. Actin minimizes these heterogeneities by reducing the mesh size of the composites and supporting microtubules against buckling. Composites also undergo a sharp transition from strain softening to stiffening when the fraction of microtubules (ϕT) exceeds 0.5, which we show arises from faster poroelastic relaxation and suppressed actin bending fluctuations. The force after bead displacement relaxes via power-law decay after an initial period of minimal relaxation. The short-time relaxation profiles (t < 0.06 s) arise from poroelastic and bending contributions, whereas the long-time power-law relaxation is indicative of filaments reptating out of deformed entanglement constraints. The scaling exponents for the long-time relaxation exhibit a nonmonotonic dependence on ϕT, reaching a maximum for equimolar composites (ϕT = 0.5), suggesting that reptation is fastest in ϕT = 0.5 composites. Corresponding mobility measurements of steady-state actin and microtubules show that both filaments are indeed the most mobile in ϕT = 0.5 composites. This nonmonotonic dependence of mobility on ϕT demonstrates the important interplay between mesh size and filament rigidity in polymer networks and highlights the surprising emergent properties that can arise in composites.
Collapse
Affiliation(s)
- Shea N Ricketts
- Department of Physics and Biophysics, University of San Diego, San Diego, California
| | - Jennifer L Ross
- Department of Physics, University of Massachusetts Amherst, Amherst, Massachusetts
| | | |
Collapse
|
15
|
Pegoraro AF, Janmey P, Weitz DA. Mechanical Properties of the Cytoskeleton and Cells. Cold Spring Harb Perspect Biol 2017; 9:9/11/a022038. [PMID: 29092896 DOI: 10.1101/cshperspect.a022038] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SUMMARYThe cytoskeleton is the major mechanical structure of the cell; it is a complex, dynamic biopolymer network comprising microtubules, actin, and intermediate filaments. Both the individual filaments and the entire network are not simple elastic solids but are instead highly nonlinear structures. Appreciating the mechanics of biopolymer networks is key to understanding the mechanics of cells. Here, we review the mechanical properties of cytoskeletal polymers and discuss the implications for the behavior of cells.
Collapse
Affiliation(s)
- Adrian F Pegoraro
- Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| | - Paul Janmey
- Institute for Medicine and Engineering and Department of Physiology, Perelman School of Medicine, and Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - David A Weitz
- Department of Physics and School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138
| |
Collapse
|
16
|
Jaspers M, Vaessen SL, van Schayik P, Voerman D, Rowan AE, Kouwer PHJ. Nonlinear mechanics of hybrid polymer networks that mimic the complex mechanical environment of cells. Nat Commun 2017; 8:15478. [PMID: 28541273 PMCID: PMC5458517 DOI: 10.1038/ncomms15478] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 04/03/2017] [Indexed: 12/20/2022] Open
Abstract
The mechanical properties of cells and the extracellular environment they reside in are governed by a complex interplay of biopolymers. These biopolymers, which possess a wide range of stiffnesses, self-assemble into fibrous composite networks such as the cytoskeleton and extracellular matrix. They interact with each other both physically and chemically to create a highly responsive and adaptive mechanical environment that stiffens when stressed or strained. Here we show that hybrid networks of a synthetic mimic of biological networks and either stiff, flexible and semi-flexible components, even very low concentrations of these added components, strongly affect the network stiffness and/or its strain-responsive character. The stiffness (persistence length) of the second network, its concentration and the interaction between the components are all parameters that can be used to tune the mechanics of the hybrids. The equivalence of these hybrids with biological composites is striking.
Collapse
Affiliation(s)
- Maarten Jaspers
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Sarah L. Vaessen
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Pim van Schayik
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Dion Voerman
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Alan E. Rowan
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Brisbane, Queensland 4072, Australia
| | - Paul H. J. Kouwer
- Department of Molecular Materials, Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| |
Collapse
|
17
|
Costigliola N, Ding L, Burckhardt CJ, Han SJ, Gutierrez E, Mota A, Groisman A, Mitchison TJ, Danuser G. Vimentin fibers orient traction stress. Proc Natl Acad Sci U S A 2017; 114:5195-5200. [PMID: 28465431 PMCID: PMC5441818 DOI: 10.1073/pnas.1614610114] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The intermediate filament vimentin is required for cells to transition from the epithelial state to the mesenchymal state and migrate as single cells; however, little is known about the specific role of vimentin in the regulation of mesenchymal migration. Vimentin is known to have a significantly greater ability to resist stress without breaking in vitro compared with actin or microtubules, and also to increase cell elasticity in vivo. Therefore, we hypothesized that the presence of vimentin could support the anisotropic mechanical strain of single-cell migration. To study this, we fluorescently labeled vimentin with an mEmerald tag using TALEN genome editing. We observed vimentin architecture in migrating human foreskin fibroblasts and found that network organization varied from long, linear bundles, or "fibers," to shorter fragments with a mesh-like organization. We developed image analysis tools employing steerable filtering and iterative graph matching to characterize the fibers embedded in the surrounding mesh. Vimentin fibers were aligned with fibroblast branching and migration direction. The presence of the vimentin network was correlated with 10-fold slower local actin retrograde flow rates, as well as spatial homogenization of actin-based forces transmitted to the substrate. Vimentin fibers coaligned with and were required for the anisotropic orientation of traction stresses. These results indicate that the vimentin network acts as a load-bearing superstructure capable of integrating and reorienting actin-based forces. We propose that vimentin's role in cell motility is to govern the alignment of traction stresses that permit single-cell migration.
Collapse
Affiliation(s)
- Nancy Costigliola
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115
| | - Liya Ding
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Christoph J Burckhardt
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Sangyoon J Han
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
- Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Edgar Gutierrez
- Department of Physics, University of California, San Diego, La Jolla, CA 92093
| | - Andressa Mota
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115
| | - Alex Groisman
- Department of Physics, University of California, San Diego, La Jolla, CA 92093
| | | | - Gaudenz Danuser
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115;
- Department of Cell Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| |
Collapse
|
18
|
Abstract
Proteins of the intermediate filament (IF) supergene family are ubiquitous structural components that comprise, in a cell type-specific manner, the cytoskeleton proper in animal tissues. All IF proteins show a distinctly organized, extended α-helical conformation prone to form two-stranded coiled coils, which are the basic building blocks of these highly flexible, stress-resistant cytoskeletal filaments. IF proteins are highly charged, thus representing versatile polyampholytes with multiple functions. Taking vimentin, keratins, and the nuclear lamins as our prime examples, we present an overview of their molecular and structural parameters. These, in turn, document the ability of IF proteins to form distinct, highly diverse supramolecular assemblies and biomaterials found, for example, at the inner nuclear membrane, throughout the cytoplasm, and in highly complex extracellular appendages, such as hair and nails, of vertebrate organisms. Ultimately, our aim is to set the stage for a more rational understanding of the immediate effects that missense mutations in IF genes have on cellular functions and for their far-reaching impact on the development of the numerous IF diseases caused by them.
Collapse
Affiliation(s)
- Harald Herrmann
- Functional Architecture of the Cell (B065), German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany, and Institute of Neuropathology, University Hospital Erlangen, D-91054 Erlangen, Germany
| | - Ueli Aebi
- Biozentrum, University of Basel, CH-4056 Basel, Switzerland
| |
Collapse
|
19
|
Morris E, Chavez M, Tan C. Dynamic biomaterials: toward engineering autonomous feedback. Curr Opin Biotechnol 2016; 39:97-104. [PMID: 26974245 DOI: 10.1016/j.copbio.2016.02.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/31/2022]
Abstract
Dynamic biomaterials are biocompatible engineered systems capable of sensing and actively responding to their surrounding environment. They are of growing interest, both as models in basic research to understand complex cellular systems and in medical applications. Here, we review recent advances in nano-scale and micro-scale biomaterials, specifically artificial cells consisting of compartmentalized biochemical reactions and biologically compatible hydrogels. These dynamic biomaterials respond to stimuli through triggered reactions, reaction cascades, logic gates, and autonomous feedback loops. We outline the advances and remaining challenges in implementing such 'smart' biomaterials capable of autonomously responding to environmental stimuli.
Collapse
Affiliation(s)
- Eliza Morris
- Department of Biomedical Engineering, University of California Davis, Davis, USA
| | - Michael Chavez
- Department of Biomedical Engineering, University of California Davis, Davis, USA
| | - Cheemeng Tan
- Department of Biomedical Engineering, University of California Davis, Davis, USA.
| |
Collapse
|
20
|
Jarrin M, Young L, Wu W, Girkin JM, Quinlan RA. In vivo, Ex Vivo, and In Vitro Approaches to Study Intermediate Filaments in the Eye Lens. Methods Enzymol 2016; 568:581-611. [DOI: 10.1016/bs.mie.2015.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
21
|
Mechanics and dynamics of reconstituted cytoskeletal systems. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3038-42. [PMID: 26130089 DOI: 10.1016/j.bbamcr.2015.06.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 01/21/2023]
Abstract
The intracellular cytoskeleton is an active dynamic network of filaments and associated binding proteins that control key cellular properties, such as cell shape and mechanics. Due to the inherent complexity of the cell, reconstituted model systems have been successfully employed to gain an understanding of the fundamental physics governing cytoskeletal processes. Here, we review recent advances and key aspects of these reconstituted systems. We focus on the importance of assembly kinetics and dynamic arrest in determining network mechanics, and highlight novel emergent behavior occurring through interactions between cytoskeletal components in more complex networks incorporating multiple biopolymers and molecular motors.
Collapse
|
22
|
Fischer RS, Fowler VM. Thematic Minireview Series: The State of the Cytoskeleton in 2015. J Biol Chem 2015; 290:17133-6. [PMID: 25957399 DOI: 10.1074/jbc.r115.663716] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The study of cytoskeletal polymers has been an active area of research for more than 70 years. However, despite decades of pioneering work by some of the brightest scientists in biochemistry, cell biology, and physiology, many central questions regarding the polymers themselves are only now starting to be answered. For example, although it has long been appreciated that the actin cytoskeleton provides contractility and couples biochemical responses with mechanical stresses in cells, only recently have we begun to understand how the actin polymer itself responds to mechanical loads. Likewise, although it has long been appreciated that the microtubule cytoskeleton can be post-translationally modified, only recently have the enzymes responsible for these modifications been characterized, so that we can now begin to understand how these modifications alter the polymerization and regulation of microtubule structures. Even the septins in eukaryotes and the cytoskeletal polymers of prokaryotes have yielded new insights due to recent advances in microscopy techniques. In this thematic series of minireviews, these topics are covered by some of the very same scientists who generated these recent insights, thereby providing us with an overview of the State of the Cytoskeleton in 2015.
Collapse
Affiliation(s)
- Robert S Fischer
- From the NHLBI, National Institutes of Health, Bethesda, Maryland 20892 and
| | - Velia M Fowler
- the Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
| |
Collapse
|