1
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Rogers J, Bajur AT, Salaita K, Spillane KM. Mechanical control of antigen detection and discrimination by T and B cell receptors. Biophys J 2024; 123:2234-2255. [PMID: 38794795 DOI: 10.1016/j.bpj.2024.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/10/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024] Open
Abstract
The adaptive immune response is orchestrated by just two cell types, T cells and B cells. Both cells possess the remarkable ability to recognize virtually any antigen through their respective antigen receptors-the T cell receptor (TCR) and B cell receptor (BCR). Despite extensive investigations into the biochemical signaling events triggered by antigen recognition in these cells, our ability to predict or control the outcome of T and B cell activation remains elusive. This challenge is compounded by the sensitivity of T and B cells to the biophysical properties of antigens and the cells presenting them-a phenomenon we are just beginning to understand. Recent insights underscore the central role of mechanical forces in this process, governing the conformation, signaling activity, and spatial organization of TCRs and BCRs within the cell membrane, ultimately eliciting distinct cellular responses. Traditionally, T cells and B cells have been studied independently, with researchers working in parallel to decipher the mechanisms of activation. While these investigations have unveiled many overlaps in how these cell types sense and respond to antigens, notable differences exist. To fully grasp their biology and harness it for therapeutic purposes, these distinctions must be considered. This review compares and contrasts the TCR and BCR, placing emphasis on the role of mechanical force in regulating the activity of both receptors to shape cellular and humoral adaptive immune responses.
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Affiliation(s)
- Jhordan Rogers
- Department of Chemistry, Emory University, Atlanta, Georgia
| | - Anna T Bajur
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
| | - Katelyn M Spillane
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom; Department of Life Sciences, Imperial College London, London, United Kingdom.
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2
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Werner ME, Ray DD, Breen C, Staddon MF, Jug F, Banerjee S, Maddox AS. Mechanical and biochemical feedback combine to generate complex contractile oscillations in cytokinesis. Curr Biol 2024; 34:3201-3214.e5. [PMID: 38991614 DOI: 10.1016/j.cub.2024.06.037] [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: 12/08/2023] [Revised: 04/22/2024] [Accepted: 06/13/2024] [Indexed: 07/13/2024]
Abstract
The actomyosin cortex is an active material that generates force to drive shape changes via cytoskeletal remodeling. Cytokinesis is the essential cell division event during which a cortical actomyosin ring closes to separate two daughter cells. Our active gel theory predicted that actomyosin systems controlled by a biochemical oscillator and experiencing mechanical strain would exhibit complex spatiotemporal behavior. To test whether active materials in vivo exhibit spatiotemporally complex kinetics, we imaged the C. elegans embryo with unprecedented temporal resolution and discovered that sections of the cytokinetic cortex undergo periodic phases of acceleration and deceleration. Contractile oscillations exhibited a range of periodicities, including those much longer periods than the timescale of RhoA pulses, which was shorter in cytokinesis than in any other biological context. Modifying mechanical feedback in vivo or in silico revealed that the period of contractile oscillation is prolonged as a function of the intensity of mechanical feedback. Fast local ring ingression occurs where speed oscillations have long periods, likely due to increased local stresses and, therefore, mechanical feedback. Fast ingression also occurs where material turnover is high, in vivo and in silico. We propose that downstream of initiation by pulsed RhoA activity, mechanical feedback, including but not limited to material advection, extends the timescale of contractility beyond that of biochemical input and, therefore, makes it robust to fluctuations in activation. Circumferential propagation of contractility likely allows for sustained contractility despite cytoskeletal remodeling necessary to recover from compaction. Thus, like biochemical feedback, mechanical feedback affords active materials responsiveness and robustness.
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Affiliation(s)
- Michael E Werner
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Dylan D Ray
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Coleman Breen
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Michael F Staddon
- Center for Systems Biology Dresden, Max Planck Institute for the Physics of Complex Systems, and Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Florian Jug
- Computational Biology Research Centre, Human Technopole, Milan, Italy
| | - Shiladitya Banerjee
- Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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3
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Carlucci LA, Johnson KC, Thomas WE. FimH-mannose noncovalent bonds survive minutes to hours under force. Biophys J 2024:S0006-3495(24)00440-5. [PMID: 38961621 DOI: 10.1016/j.bpj.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 05/10/2024] [Accepted: 07/01/2024] [Indexed: 07/05/2024] Open
Abstract
The adhesin FimH is expressed by commensal Escherichia coli and is implicated in urinary tract infections, where it mediates adhesion to mannosylated glycoproteins on urinary and intestinal epithelial cells in the presence of a high-shear fluid environment. The FimH-mannose bond exhibits catch behavior in which bond lifetime increases with force, because tensile force induces a transition in FimH from a compact native to an elongated activated conformation with a higher affinity to mannose. However, the lifetime of the activated state of FimH has not been measured under force. Here we apply multiplexed magnetic tweezers to apply a preload force to activate FimH bonds with yeast mannan, then we measure the lifetime of these activated bonds under a wide range of forces above and below the preload force. A higher fraction of FimH-mannan bonds were activated above than below a critical preload force, confirming the FimH catch bond behavior. Once activated, FimH detached from mannose with multi-state kinetics, suggesting the existence of two bound states with a 20-fold difference in dissociation rates. The average lifetime of activated FimH-mannose bonds was 1000 to 10,000 s at forces of 30-70 pN. Structural explanations of the two bound states and the high force resistance provide insights into structural mechanisms for long-lived, force-resistant biomolecular interactions.
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Affiliation(s)
- Laura A Carlucci
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Keith C Johnson
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Wendy E Thomas
- Department of Bioengineering, University of Washington, Seattle, Washington.
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4
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Pitha I, Du L, Nguyen TD, Quigley H. IOP and glaucoma damage: The essential role of optic nerve head and retinal mechanosensors. Prog Retin Eye Res 2024; 99:101232. [PMID: 38110030 PMCID: PMC10960268 DOI: 10.1016/j.preteyeres.2023.101232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023]
Abstract
There are many unanswered questions on the relation of intraocular pressure to glaucoma development and progression. IOP itself cannot be distilled to a single, unifying value, because IOP level varies over time, differs depending on ocular location, and can be affected by method of measurement. Ultimately, IOP level creates mechanical strain that affects axonal function at the optic nerve head which causes local extracellular matrix remodeling and retinal ganglion cell death - hallmarks of glaucoma and the cause of glaucomatous vision loss. Extracellular tissue strain at the ONH and lamina cribrosa is regionally variable and differs in magnitude and location between healthy and glaucomatous eyes. The ultimate targets of IOP-induced tissue strain in glaucoma are retinal ganglion cell axons at the optic nerve head and the cells that support axonal function (astrocytes, the neurovascular unit, microglia, and fibroblasts). These cells sense tissue strain through a series of signals that originate at the cell membrane and alter cytoskeletal organization, migration, differentiation, gene transcription, and proliferation. The proteins that translate mechanical stimuli into molecular signals act as band-pass filters - sensing some stimuli while ignoring others - and cellular responses to stimuli can differ based on cell type and differentiation state. Therefore, to fully understand the IOP signals that are relevant to glaucoma, it is necessary to understand the ultimate cellular targets of IOP-induced mechanical stimuli and their ability to sense, ignore, and translate these signals into cellular actions.
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Affiliation(s)
- Ian Pitha
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Center for Nanomedicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Liya Du
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thao D Nguyen
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD, USA
| | - Harry Quigley
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Glaucoma Center of Excellence, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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5
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Barkan CO, Bruinsma RF. Topology of molecular deformations induces triphasic catch bonding in selectin-ligand bonds. Proc Natl Acad Sci U S A 2024; 121:e2315866121. [PMID: 38294934 PMCID: PMC10861892 DOI: 10.1073/pnas.2315866121] [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: 09/14/2023] [Accepted: 12/15/2023] [Indexed: 02/02/2024] Open
Abstract
Among the long-standing efforts to elucidate the physical mechanisms of protein-ligand catch bonding, particular attention has been directed at the family of selectin proteins. Selectins exhibit slip, catch-slip, and slip-catch-slip bonding, with minor structural modifications causing major changes in selectins' response to force. How can a single structural mechanism allow interconversion between these various behaviors? We present a unifying theory of selectin-ligand catch bonding, using a structurally motivated free energy landscape to show how the topology of force-induced deformations of the molecular system produces the full range of observed behaviors. We find that the pathway of bond rupture deforms in non-trivial ways, such that unbinding dynamics depend sensitively on force. This implies a severe breakdown of Bell's theory-a paradigmatic theory used widely in catch bond modeling-raising questions about the suitability of Bell's theory in modeling other catch bonds. Our approach can be applied broadly to other protein-ligand systems.
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Affiliation(s)
- Casey O. Barkan
- Department of Physics and Astronomy, University of California, Los Angeles, CA90095
| | - Robijn F. Bruinsma
- Department of Physics and Astronomy, University of California, Los Angeles, CA90095
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6
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Göz M, Steinecker SM, Pohl GM, Walhorn V, Milting H, Anselmetti D. Cardiac desmosomal adhesion relies on ideal-, slip- and catch bonds. Sci Rep 2024; 14:2555. [PMID: 38297017 PMCID: PMC10830561 DOI: 10.1038/s41598-024-52725-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/23/2024] [Indexed: 02/02/2024] Open
Abstract
The cardiac muscle consists of individual cardiomyocytes that are mechanically linked by desmosomes. Desmosomal adhesion is mediated by densely packed and organized cadherins which, in presence of Ca2+, stretch out their extracellular domains (EC) and dimerize with opposing binding partners by exchanging an N-terminal tryptophan. The strand-swap binding motif of cardiac cadherins like desmocollin 2 (Dsc2) (and desmoglein2 alike) is highly specific but of low affinity with average bond lifetimes in the range of approximately 0.3 s. Notably, despite this comparatively weak interaction, desmosomes mediate a stable, tensile-resistant bond. In addition, force mediated dissociation of strand-swap dimers exhibit a reduced bond lifetime as external forces increase (slip bond). Using atomic force microscopy based single molecule force spectroscopy (AFM-SMFS), we demonstrate that Dsc2 has two further binding modes that, in addition to strand-swap dimers, most likely play a significant role in the integrity of the cardiac muscle. At short interaction times, the Dsc2 monomers associate only loosely, as can be seen from short-lived force-independent bonds. These ideal bonds are a precursor state and probably stabilize the formation of the self-inhibiting strand-swap dimer. The addition of tryptophan in the measurement buffer acts as a competitive inhibitor, preventing the N-terminal strand exchange. Here, Dsc2 dimerizes as X-dimer which clearly shows a tri-phasic slip-catch-slip type of dissociation. Within the force-mediated transition (catch) regime, Dsc2 dimers switch between a rather brittle low force and a strengthened high force adhesion state. As a result, we can assume that desmosomal adhesion is mediated not only by strand-swap dimers (slip) but also by their precursor states (ideal bond) and force-activated X-dimers (catch bond).
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Affiliation(s)
- Manuel Göz
- Department of Physics, Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitätstraße 25, 33615, Bielefeld, Germany
| | - Sylvia M Steinecker
- Department of Physics, Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitätstraße 25, 33615, Bielefeld, Germany
| | - Greta M Pohl
- Erich & Hanna Klessmann Institute for Cardiovascular Research and Development, Heart and Diabetes Center NRW, University Hospital of the Ruhr-University Bochum, Georgstraße 11, Bad Oeynhausen, Germany
| | - Volker Walhorn
- Department of Physics, Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitätstraße 25, 33615, Bielefeld, Germany.
| | - Hendrik Milting
- Erich & Hanna Klessmann Institute for Cardiovascular Research and Development, Heart and Diabetes Center NRW, University Hospital of the Ruhr-University Bochum, Georgstraße 11, Bad Oeynhausen, Germany
| | - Dario Anselmetti
- Department of Physics, Experimental Biophysics and Applied Nanoscience, Bielefeld University, Universitätstraße 25, 33615, Bielefeld, Germany
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7
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Livne G, Gat S, Armon S, Bernheim-Groswasser A. Self-assembled active actomyosin gels spontaneously curve and wrinkle similar to biological cells and tissues. Proc Natl Acad Sci U S A 2024; 121:e2309125121. [PMID: 38175871 PMCID: PMC10786314 DOI: 10.1073/pnas.2309125121] [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: 05/31/2023] [Accepted: 11/28/2023] [Indexed: 01/06/2024] Open
Abstract
Living systems adopt a diversity of curved and highly dynamic shapes. These diverse morphologies appear on many length scales, from cells to tissues and organismal scales. The common driving force for these dynamic shape changes are contractile stresses generated by myosin motors in the cell cytoskeleton, that converts chemical energy into mechanical work. A good understanding of how contractile stresses in the cytoskeleton arise into different three-dimensional (3D) shapes and what are the shape selection rules that determine their final configurations is still lacking. To obtain insight into the relevant physical mechanisms, we recreate the actomyosin cytoskeleton in vitro, with precisely controlled composition and initial geometry. A set of actomyosin gel discs, intrinsically identical but of variable initial geometry, dynamically self-organize into a family of 3D shapes, such as domes and wrinkled shapes, without the need for specific preprogramming or additional regulation. Shape deformation is driven by the spontaneous emergence of stress gradients driven by myosin and is encoded in the initial disc radius to thickness aspect ratio, which may indicate shaping scalability. Our results suggest that while the dynamical pathways may depend on the detailed interactions between the different microscopic components within the gel, the final selected shapes obey the general theory of elastic deformations of thin sheets. Altogether, our results emphasize the importance for the emergence of active stress gradients for buckling-driven shape deformations and provide insights on the mechanically induced spontaneous shape transitions in contractile active matter, revealing potential shared mechanisms with living systems across scales.
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Affiliation(s)
- Gefen Livne
- Department of Chemical Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva84105, Israel
| | - Shachar Gat
- Department of Chemical Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva84105, Israel
| | - Shahaf Armon
- Department of Physics, Weizmann Institute of Science, Rehovot76100, Israel
| | - Anne Bernheim-Groswasser
- Department of Chemical Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva84105, Israel
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8
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Werner ME, Ray DD, Breen C, Staddon MF, Jug F, Banerjee S, Maddox AS. Mechanical positive feedback and biochemical negative feedback combine to generate complex contractile oscillations in cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.01.569672. [PMID: 38076901 PMCID: PMC10705528 DOI: 10.1101/2023.12.01.569672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Contractile force generation by the cortical actomyosin cytoskeleton is essential for a multitude of biological processes. The actomyosin cortex behaves as an active material that drives local and large-scale shape changes via cytoskeletal remodeling in response to biochemical cues and feedback loops. Cytokinesis is the essential cell division event during which a cortical actomyosin ring generates contractile force to change cell shape and separate two daughter cells. Our recent work with active gel theory predicts that actomyosin systems under the control of a biochemical oscillator and experiencing mechanical strain will exhibit complex spatiotemporal behavior, but cytokinetic contractility was thought to be kinetically simple. To test whether active materials in vivo exhibit spatiotemporally complex kinetics, we used 4-dimensional imaging with unprecedented temporal resolution and discovered sections of the cytokinetic cortex undergo periodic phases of acceleration and deceleration. Quantification of ingression speed oscillations revealed wide ranges of oscillation period and amplitude. In the cytokinetic ring, activity of the master regulator RhoA pulsed with a timescale of approximately 20 seconds, shorter than that reported for any other biological context. Contractility oscillated with 20-second periodicity and with much longer periods. A combination of in vivo and in silico approaches to modify mechanical feedback revealed that the period of contractile oscillation is prolonged as a function of the intensity of mechanical feedback. Effective local ring ingression is characterized by slower speed oscillations, likely due to increased local stresses and therefore mechanical feedback. Fast ingression also occurs where material turnover is high, in vivo and in silico . We propose that downstream of initiation by pulsed RhoA activity, mechanical positive feedback, including but not limited to material advection, extends the timescale of contractility beyond that of biochemical input and therefore makes it robust to fluctuations in activation. Circumferential propagation of contractility likely allows sustained contractility despite cytoskeletal remodeling necessary to recover from compaction. Our work demonstrates that while biochemical feedback loops afford systems responsiveness and robustness, mechanical feedback must also be considered to describe and understand the behaviors of active materials in vivo .
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9
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Cencer CS, Silverman JB, Meenderink LM, Krystofiak ES, Millis BA, Tyska MJ. Adhesion-based capture stabilizes nascent microvilli at epithelial cell junctions. Dev Cell 2023; 58:2048-2062.e7. [PMID: 37832537 PMCID: PMC10615885 DOI: 10.1016/j.devcel.2023.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/21/2023] [Accepted: 09/14/2023] [Indexed: 10/15/2023]
Abstract
To maximize solute transport, epithelial cells build an apical "brush border," where thousands of microvilli are linked to their neighbors by protocadherin-containing intermicrovillar adhesion complexes (IMACs). Previous studies established that the IMAC is needed to build a mature brush border, but how this complex contributes to the accumulation of new microvilli during differentiation remains unclear. We found that early in differentiation, mouse, human, and porcine epithelial cells exhibit a marginal accumulation of microvilli, which span junctions and interact with protrusions on neighboring cells using IMAC protocadherins. These transjunctional IMACs are highly stable and reinforced by tension across junctions. Finally, long-term live imaging showed that the accumulation of microvilli at cell margins consistently leads to accumulation in medial regions. Thus, nascent microvilli are stabilized by a marginal capture mechanism that depends on the formation of transjunctional IMACs. These results may offer insights into how apical specializations are assembled in diverse epithelial systems.
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Affiliation(s)
- Caroline S Cencer
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jennifer B Silverman
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Leslie M Meenderink
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA; United States Department of Veterans Affairs, Tennessee Valley Health Care System, Nashville, TN 37212, USA
| | - Evan S Krystofiak
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan A Millis
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Biomedical Engineering, Vanderbilt University School of Engineering, Nashville, TN 37235, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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10
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Belyaev AV, Fedotova IV. Molecular mechanisms of catch bonds and their implications for platelet hemostasis. Biophys Rev 2023; 15:1233-1256. [PMID: 37974999 PMCID: PMC10643804 DOI: 10.1007/s12551-023-01144-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/07/2023] [Indexed: 11/19/2023] Open
Abstract
Adhesive molecular bonds between blood cells are essential for thrombosis and hemostasis as they provide means for platelet adhesion, aggregation, and signaling in flowing blood. According to the nowadays conventional definition, a "catch" bond is a type of non-covalent bio-molecular bridge, whose dissociation lifetime counter-intuitively increases with applied tensile force. Following recent experimental findings, such receptor-ligand protein bonds are vital to the blood cells involved in the prevention of bleeding (hemostatic response) and infection (immunity). In this review, we examine the up-to-date experimental discoveries and theoretical insights about catch bonds between the blood cells, their biomechanical principles at the molecular level, and their role in platelet thrombosis and hemostasis.
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Affiliation(s)
- Aleksey V. Belyaev
- Faculty of Physics, M.V.Lomonosov Moscow State University, 1, Leninskiye Gory, build.2, Moscow, 119991 Russia
| | - Irina V. Fedotova
- Faculty of Physics, M.V.Lomonosov Moscow State University, 1, Leninskiye Gory, build.2, Moscow, 119991 Russia
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11
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Cortes DB, Maddox PS, Nédéléç FJ, Maddox AS. Contractile ring composition dictates kinetics of in silico contractility. Biophys J 2023; 122:3611-3629. [PMID: 36540027 PMCID: PMC10541479 DOI: 10.1016/j.bpj.2022.12.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/12/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Constriction kinetics of the cytokinetic ring are expected to depend on dynamic adjustment of contractile ring composition, but the impact of ring component abundance dynamics on ring constriction is understudied. Computational models generally assume that contractile networks maintain constant total amounts of components, which is not always true. To test how compositional dynamics affect constriction kinetics, we first measured F-actin, non-muscle myosin II, septin, and anillin during Caenorhabditis elegans zygotic mitosis. A custom microfluidic device that positioned the cell with the division plane parallel to a light sheet allowed even illumination of the cytokinetic ring. Measured component abundances were implemented in a three-dimensional agent-based model of a membrane-associated contractile ring. With constant network component amounts, constriction completed with biologically unrealistic kinetics. However, imposing the measured changes in component quantities allowed this model to elicit realistic constriction kinetics. Simulated networks were more sensitive to changes in motor and filament amounts than those of crosslinkers and tethers. Our findings highlight the importance of network composition for actomyosin contraction kinetics.
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Affiliation(s)
- Daniel B Cortes
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC.
| | - Paul S Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Francois J Nédéléç
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC.
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12
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Ayres CM, Corcelli SA, Baker BM. The Energetic Landscape of Catch Bonds in TCR Interfaces. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:325-332. [PMID: 37459192 PMCID: PMC10361606 DOI: 10.4049/jimmunol.2300121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/14/2023] [Indexed: 07/20/2023]
Abstract
Recognition of peptide/MHC complexes by αβ TCRs has traditionally been viewed through the lens of conventional receptor-ligand theory. Recent work, however, has shown that TCR recognition and T cell signaling can be profoundly influenced and tuned by mechanical forces. One outcome of applied force is the catch bond, where TCR dissociation rates decrease (half-lives increase) when limited force is applied. Although catch bond behavior is believed to be widespread in biology, its counterintuitive nature coupled with the difficulties of describing mechanisms at the structural level have resulted in considerable mystique. In this review, we demonstrate that viewing catch bonds through the lens of energy landscapes, barriers, and the ensuing reaction rates can help demystify catch bonding and provide a foundation on which atomic-level TCR catch bond mechanisms can be built.
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Affiliation(s)
- Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
- The Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN
| | - Steve A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
- The Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN
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13
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Choi HK, Cong P, Ge C, Natarajan A, Liu B, Zhang Y, Li K, Rushdi MN, Chen W, Lou J, Krogsgaard M, Zhu C. Catch bond models may explain how force amplifies TCR signaling and antigen discrimination. Nat Commun 2023; 14:2616. [PMID: 37147290 PMCID: PMC10163261 DOI: 10.1038/s41467-023-38267-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 04/24/2023] [Indexed: 05/07/2023] Open
Abstract
The TCR integrates forces in its triggering process upon interaction with pMHC. Force elicits TCR catch-slip bonds with strong pMHCs but slip-only bonds with weak pMHCs. We develop two models and apply them to analyze 55 datasets, demonstrating the models' ability to quantitatively integrate and classify a broad range of bond behaviors and biological activities. Comparing to a generic two-state model, our models can distinguish class I from class II MHCs and correlate their structural parameters with the TCR/pMHC's potency to trigger T cell activation. The models are tested by mutagenesis using an MHC and a TCR mutated to alter conformation changes. The extensive comparisons between theory and experiment provide model validation and testable hypothesis regarding specific conformational changes that control bond profiles, thereby suggesting structural mechanisms for the inner workings of the TCR mechanosensing machinery and plausible explanations of why and how force may amplify TCR signaling and antigen discrimination.
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Affiliation(s)
- Hyun-Kyu Choi
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Peiwen Cong
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Chenghao Ge
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Amgen Inc., One Amgen Center Dr., Thousand Oaks, CA, 91320, USA
| | - Aswin Natarajan
- Laura and Isaac Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Baoyu Liu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, 84112, USA
| | - Yong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Kaitao Li
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Muaz Nik Rushdi
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA
- Medtronic CO., Minneapolis, MN, 55432, USA
| | - Wei Chen
- Department of Cell Biology, Zhejiang University School of Medicine, Hangzhou, 310058, China
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jizhong Lou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Michelle Krogsgaard
- Laura and Isaac Perlmutter Cancer Center, New York University Grossman School of Medicine, New York, NY, 10016, USA
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, 10016, USA
| | - Cheng Zhu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30332, USA.
- Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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14
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Cencer CS, Silverman JB, Meenderink LM, Krystofiak ES, Millis BA, Tyska MJ. Adhesion-based capture stabilizes nascent microvilli at epithelial cell junctions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.08.531705. [PMID: 36945471 PMCID: PMC10028856 DOI: 10.1101/2023.03.08.531705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Differentiated transporting epithelial cells present an extensive apical array of microvilli - a "brush border" - where neighboring microvilli are linked together by intermicrovillar adhesion complexes (IMACs) composed of protocadherins CDHR2 and CDHR5. Although loss-of-function studies provide strong evidence that IMAC function is needed to build a mature brush border, how the IMAC contributes to the stabilization and accumulation of nascent microvilli remains unclear. We found that, early in differentiation, the apical surface exhibits a marginal accumulation of microvilli, characterized by higher packing density relative to medial regions of the surface. While medial microvilli are highly dynamic and sample multiple orientations over time, marginal protrusions exhibit constrained motion and maintain a vertical orientation. Unexpectedly, we found that marginal microvilli span the junctional space and contact protrusions on neighboring cells, mediated by complexes of CDHR2/CDHR5. FRAP analysis indicated that these transjunctional IMACs are highly stable relative to adhesion complexes between medial microvilli, which explains the restricted motion of protrusions in the marginal zone. Finally, long-term live imaging revealed that the accumulation of microvilli at cell margins consistently leads to accumulation in medial regions of the cell. Collectively, our findings suggest that nascent microvilli are stabilized by a capture mechanism that is localized to cell margins and enabled by the transjunctional formation of IMACs. These results inform our understanding of how apical specializations are assembled in diverse epithelial systems.
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15
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Li T, Dufresne ER, Kröger M, Heyden S. Siloxane Molecules: Nonlinear Elastic Behavior and Fracture Characteristics. Macromolecules 2023; 56:1303-1310. [PMID: 36874533 PMCID: PMC9979691 DOI: 10.1021/acs.macromol.2c02576] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/17/2023] [Indexed: 02/10/2023]
Abstract
Fracture phenomena in soft materials span multiple length and time scales. This poses a major challenge in computational modeling and predictive materials design. To pass quantitatively from molecular to continuum scales, a precise representation of the material response at the molecular level is vital. Here, we derive the nonlinear elastic response and fracture characteristics of individual siloxane molecules using molecular dynamics (MD) studies. For short chains, we find deviations from classical scalings for both the effective stiffness and mean chain rupture times. A simple model of a nonuniform chain of Kuhn segments captures the observed effect and agrees well with MD data. We find that the dominating fracture mechanism depends on the applied force scale in a nonmonotonic fashion. This analysis suggests that common polydimethylsiloxane (PDMS) networks fail at cross-linking points. Our results can be readily lumped into coarse-grained models. Although focusing on PDMS as a model system, our study presents a general procedure to pass beyond the window of accessible rupture times in MD studies employing mean first passage time theory, which can be exploited for arbitrary molecular systems.
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Affiliation(s)
- Tianchi Li
- Soft and Living Materials, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Eric R Dufresne
- Soft and Living Materials, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Martin Kröger
- Polymer Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland.,Magnetism and Interface Physics, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Stefanie Heyden
- Soft and Living Materials, Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
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16
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Light-driven biological actuators to probe the rheology of 3D microtissues. Nat Commun 2023; 14:717. [PMID: 36759504 PMCID: PMC9911700 DOI: 10.1038/s41467-023-36371-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/26/2023] [Indexed: 02/11/2023] Open
Abstract
The mechanical properties of biological tissues are key to their physical integrity and function. Although external loading or biochemical treatments allow the estimation of these properties globally, it remains difficult to assess how such external stimuli compare with cell-generated contractions. Here we engineer microtissues composed of optogenetically-modified fibroblasts encapsulated within collagen. Using light to control the activity of RhoA, a major regulator of cellular contractility, we induce local contractions within microtissues, while monitoring microtissue stress and strain. We investigate the regulation of these local contractions and their spatio-temporal distribution. We demonstrate the potential of our technique for quantifying tissue elasticity and strain propagation, before examining the possibility of using light to create and map local anisotropies in mechanically heterogeneous microtissues. Altogether, our results open an avenue to guide the formation of tissues while non-destructively charting their rheology in real time, using their own constituting cells as internal actuators.
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17
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Muresan CG, Sun ZG, Yadav V, Tabatabai AP, Lanier L, Kim JH, Kim T, Murrell MP. F-actin architecture determines constraints on myosin thick filament motion. Nat Commun 2022; 13:7008. [PMID: 36385016 PMCID: PMC9669029 DOI: 10.1038/s41467-022-34715-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 11/03/2022] [Indexed: 11/17/2022] Open
Abstract
Active stresses are generated and transmitted throughout diverse F-actin architectures within the cell cytoskeleton, and drive essential behaviors of the cell, from cell division to migration. However, while the impact of F-actin architecture on the transmission of stress is well studied, the role of architecture on the ab initio generation of stresses remains less understood. Here, we assemble F-actin networks in vitro, whose architectures are varied from branched to bundled through F-actin nucleation via Arp2/3 and the formin mDia1. Within these architectures, we track the motions of embedded myosin thick filaments and connect them to the extent of F-actin network deformation. While mDia1-nucleated networks facilitate the accumulation of stress and drive contractility through enhanced actomyosin sliding, branched networks prevent stress accumulation through the inhibited processivity of thick filaments. The reduction in processivity is due to a decrease in translational and rotational motions constrained by the local density and geometry of F-actin.
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Affiliation(s)
- Camelia G Muresan
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - Zachary Gao Sun
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA
| | - Vikrant Yadav
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - A Pasha Tabatabai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - Laura Lanier
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA
| | - June Hyung Kim
- Weldon School of Biomedical Engineering, Purdue University, 206S. Martin Jischke Drive, West Lafayette, IN, 47907, USA
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, 206S. Martin Jischke Drive, West Lafayette, IN, 47907, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT, 06511, USA.
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT, 06516, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, 06511, USA.
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18
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A multi-state dynamic process confers mechano-adaptation to a biological nanomachine. Nat Commun 2022; 13:5327. [PMID: 36088344 PMCID: PMC9464220 DOI: 10.1038/s41467-022-33075-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
Adaptation is a defining feature of living systems. The bacterial flagellar motor adapts to changes in the external mechanical load by adding or removing torque-generating (stator) units. But the molecular mechanism behind this mechano-adaptation remains unclear. Here, we combine single motor eletrorotation experiments and theoretical modeling to show that mechano-adaptation of the flagellar motor is enabled by multiple mechanosensitive internal states. Dwell time statistics from experiments suggest the existence of at least two bound states with a high and a low unbinding rate, respectively. A first-passage-time analysis of a four-state model quantitatively explains the experimental data and determines the transition rates among all four states. The torque generated by bound stator units controls their effective unbinding rate by modulating the transition between the bound states, possibly via a catch bond mechanism. Similar force-mediated feedback enabled by multiple internal states may apply to adaptation in other macromolecular complexes. Combining experiments with modeling, Wadhwa et al. propose a model for mechano-adaptation in the bacterial flagellar motor, finding that load-dependent transitions between multiple internal states govern the binding and unbinding of subunits.
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19
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Jia H, Flommersfeld J, Heymann M, Vogel SK, Franquelim HG, Brückner DB, Eto H, Broedersz CP, Schwille P. 3D printed protein-based robotic structures actuated by molecular motor assemblies. NATURE MATERIALS 2022; 21:703-709. [PMID: 35618822 PMCID: PMC9156402 DOI: 10.1038/s41563-022-01258-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 04/13/2022] [Indexed: 06/10/2023]
Abstract
Upscaling motor protein activity to perform work in man-made devices has long been an ambitious goal in bionanotechnology. The use of hierarchical motor assemblies, as realized in sarcomeres, has so far been complicated by the challenges of arranging sufficiently high numbers of motor proteins with nanoscopic precision. Here, we describe an alternative approach based on actomyosin cortex-like force production, allowing low complexity motor arrangements in a contractile meshwork that can be coated onto soft objects and locally activated by ATP. The design is reminiscent of a motorized exoskeleton actuating protein-based robotic structures from the outside. It readily supports the connection and assembly of micro-three-dimensional printed modules into larger structures, thereby scaling up mechanical work. We provide an analytical model of force production in these systems and demonstrate the design flexibility by three-dimensional printed units performing complex mechanical tasks, such as microhands and microarms that can grasp and wave following light activation.
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Affiliation(s)
- Haiyang Jia
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Johannes Flommersfeld
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Michael Heymann
- Max Planck Institute of Biochemistry, Martinsried, Germany
- Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Sven K Vogel
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | | | - David B Brückner
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Hiromune Eto
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Chase P Broedersz
- Arnold Sommerfeld Center for Theoretical Physics, Center for NanoScience, Ludwig-Maximilians-Universität München, Munich, Germany.
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Petra Schwille
- Max Planck Institute of Biochemistry, Martinsried, Germany.
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20
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Contini M, Altman D, Cornachione A, Rassier DE, Bagni MA. An increase in force after stretch of diaphragm fibers and myofibrils is accompanied by an increase in sarcomere length non-uniformities and Ca 2+ sensitivity. Am J Physiol Cell Physiol 2022; 323:C14-C28. [PMID: 35613356 DOI: 10.1152/ajpcell.00394.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When muscle fibers from limb muscles are stretched while activated, the force increases to a steady-state level that is higher than that produced during isometric contractions at a corresponding sarcomere length, a phenomenon known as residual force enhancement (RFE). The mechanisms responsible for the RFE are an increased stiffness of titin molecules which may lead to an increased Ca2+ sensitivity of the contractile apparatus,and the development of sarcomere length non-uniformities. RFE is not observed in cardiac muscles, which makes this phenomenon specific to certain preparations. The aim of this study was to investigate if the RFE is present in the diaphragm, and its potential association with an increased Ca2+ sensitivity and the development of sarcomere length non-uniformities. We used two preparations: single intact fibers and myofibrils isolated from the diaphragm from mice. We investigated RFE in a variety of lengths across the force-length relationship. RFE was observed in both preparations at all lengths investigated, and was larger with increasing magnitudes of stretch. RFE was accompanied by an increased Ca2+ sensitivity as shown by a change in the force-pCa2+-curve, and increased sarcomere length non-uniformities. Therefore, RFE is a phenomenon commonly observed in skeletal muscles, with mechanisms that are similar across preparations.
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Affiliation(s)
- Massimo Contini
- Department of Experimental and Clinical Medicine, University of Florence, Italy
| | - David Altman
- Department of Physics, Willamette University, Salem, OR, United States
| | - Anabelle Cornachione
- Department of Physiological Sciences, Federal University of São Carlos, São Paulo, Brazil
| | | | - Maria Angela Bagni
- Department of Experimental and Clinical Medicine, University of Florence, Italy
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21
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Mickolajczyk KJ, Olinares PDB, Chait BT, Liu S, Kapoor TM. The MIDAS domain of AAA mechanoenzyme Mdn1 forms catch bonds with two different substrates. eLife 2022; 11:73534. [PMID: 35147499 PMCID: PMC8837202 DOI: 10.7554/elife.73534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
Catch bonds are a form of mechanoregulation wherein protein-ligand interactions are strengthened by the application of dissociative tension. Currently, the best-characterized examples of catch bonds are between single protein-ligand pairs. The essential AAA (ATPase associated with diverse cellular activities) mechanoenzyme Mdn1 drives at least two separate steps in ribosome biogenesis, using its MIDAS domain to extract the ubiquitin-like (UBL) domain-containing proteins Rsa4 and Ytm1 from ribosomal precursors. However, it must subsequently release these assembly factors to reinitiate the enzymatic cycle. The mechanism underlying the switching of the MIDAS-UBL interaction between strongly and weakly bound states is unknown. Here, we use optical tweezers to investigate the force dependence of MIDAS-UBL binding. Parallel experiments with Rsa4 and Ytm1 show that forces up to ~4 pN, matching the magnitude of force produced by AAA proteins similar to Mdn1, enhance the MIDAS domain binding lifetime up to 10-fold, and higher forces accelerate dissociation. Together, our studies indicate that Mdn1's MIDAS domain can form catch bonds with more than one UBL substrate, and provide insights into how mechanoregulation may contribute to the Mdn1 enzymatic cycle during ribosome biogenesis.
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Affiliation(s)
- Keith J Mickolajczyk
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, United States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
| | - Shixin Liu
- Laboratory of Nanoscale Biophysics and Biochemistry, The Rockefeller University, New York, United States
| | - Tarun M Kapoor
- Laboratory of Chemistry and Cell Biology, The Rockefeller University, New York, United States
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22
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Murray LE, Kim H, Rice LM, Asbury CL. Catching the Conformational Wave: Measuring the Working Strokes of Protofilaments as They Curl Outward from Disassembling Microtubule Tips. Methods Mol Biol 2022; 2478:653-676. [PMID: 36063337 PMCID: PMC9542027 DOI: 10.1007/978-1-0716-2229-2_23] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Optical traps have enabled foundational studies of how mechanoenzymes such as kinesins and dynein motors walk along microtubules, how myosins move along F-actin, and how nucleic acid enzymes move along DNA or RNA. Often the filamentous substrates serve merely as passive tracks for mechanoenzymes but microtubules and F-actin are themselves dynamic protein polymers, capable of generating movement and force independently of conventional motors. Microtubule-driven forces are particularly important during mitosis, when they align duplicated chromosomes at the metaphase plate and then pull them apart during anaphase. These vital movements depend on specialized protein assemblies called kinetochores that couple the chromosomes to the tips of dynamic microtubule filaments, thereby allowing filament shortening to produce pulling forces. Although great strides have been made toward understanding the structures and functions of many kinetochore subcomplexes, the biophysical basis for their coupling to microtubule tips remains unclear. During tip disassembly, strain energy is released when straight protofilaments in the microtubule lattice curl outward, creating a conformational wave that propagates down the microtubule. A popular viewpoint is that the protofilaments as they curl outward hook elements of the kinetochore and tug on them, transferring some of their curvature strain energy to the kinetochore. As a first step toward testing this idea, we recently developed a laser trap assay to directly measure the working strokes generated by curling protofilaments. Our "wave" assay is based on an earlier pioneering study, with improvements that allow measurement of curl-driven movements as functions of force and quantification of their conformational strain energy. In this chapter, we provide a detailed protocol for our assay and describe briefly our instrument setup and data analysis methods.
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Affiliation(s)
- Lucas E. Murray
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA
| | - Haein Kim
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA
| | - Luke M. Rice
- Department of Biophysics, UT Southwestern Medical Center, Dallas TX 75390, USA
| | - Charles L. Asbury
- Department of Physiology & Biophysics, University of Washington, Seattle WA 98195, USA.,address correspondence to:
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23
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Wei X, Fang C, Gong B, Yao J, Qian J, Lin Y. Viscoelasticity of 3D actin networks dictated by the mechanochemical characteristics of cross-linkers. SOFT MATTER 2021; 17:10177-10185. [PMID: 33646227 DOI: 10.1039/d0sm01558j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this study, we report a computational investigation on how the mechanochemical characteristics of crosslinking molecules influence the viscoelasticity of three dimensional F-actin networks, an issue of key interest in analyzing the behavior of living cells and biological gels. In particular, it was found that the continuous breakage and rebinding of cross-linkers result in a locally peaked loss modulus in the rheology spectrum of the network, reflecting the fact that maximum energy dissipation is achieved when the driving frequency of the applied oscillating shear becomes comparable to the dissociation/association rate of crosslinking molecules. In addition, we showed that when subjected to constant rate of shear, an actin network can exhibit either strain hardening or softening depending on the ratio between the loading rate and unbinding speed of cross-linkers. A criterion for predicting the transition from softening to hardening was also obtained, in agreement with recent experiments. Finally, significant structural evolution was found to occur in random networks undergoing mechanical "training" (i.e. under a constant applied shear stress over a period of time), eventually leading to a pronounced anisotropic response of the network afterward which again is consistent with experimental observations.
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Affiliation(s)
- X Wei
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong, China
| | - C Fang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong, China
| | - B Gong
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, China.
| | - J Yao
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong, China
| | - J Qian
- Department of Engineering Mechanics, Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Y Lin
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China.
- HKU-Shenzhen Institute of Research and Innovation (HKU-SIRI), Guangdong, China
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24
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Vernerey FJ, Lalitha Sridhar S, Muralidharan A, Bryant SJ. Mechanics of 3D Cell-Hydrogel Interactions: Experiments, Models, and Mechanisms. Chem Rev 2021; 121:11085-11148. [PMID: 34473466 DOI: 10.1021/acs.chemrev.1c00046] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hydrogels are highly water-swollen molecular networks that are ideal platforms to create tissue mimetics owing to their vast and tunable properties. As such, hydrogels are promising cell-delivery vehicles for applications in tissue engineering and have also emerged as an important base for ex vivo models to study healthy and pathophysiological events in a carefully controlled three-dimensional environment. Cells are readily encapsulated in hydrogels resulting in a plethora of biochemical and mechanical communication mechanisms, which recapitulates the natural cell and extracellular matrix interaction in tissues. These interactions are complex, with multiple events that are invariably coupled and spanning multiple length and time scales. To study and identify the underlying mechanisms involved, an integrated experimental and computational approach is ideally needed. This review discusses the state of our knowledge on cell-hydrogel interactions, with a focus on mechanics and transport, and in this context, highlights recent advancements in experiments, mathematical and computational modeling. The review begins with a background on the thermodynamics and physics fundamentals that govern hydrogel mechanics and transport. The review focuses on two main classes of hydrogels, described as semiflexible polymer networks that represent physically cross-linked fibrous hydrogels and flexible polymer networks representing the chemically cross-linked synthetic and natural hydrogels. In this review, we highlight five main cell-hydrogel interactions that involve key cellular functions related to communication, mechanosensing, migration, growth, and tissue deposition and elaboration. For each of these cellular functions, recent experiments and the most up to date modeling strategies are discussed and then followed by a summary of how to tune hydrogel properties to achieve a desired functional cellular outcome. We conclude with a summary linking these advancements and make the case for the need to integrate experiments and modeling to advance our fundamental understanding of cell-matrix interactions that will ultimately help identify new therapeutic approaches and enable successful tissue engineering.
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Affiliation(s)
- Franck J Vernerey
- Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado 80309-0428, United States.,Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States
| | - Shankar Lalitha Sridhar
- Department of Mechanical Engineering, University of Colorado at Boulder, 1111 Engineering Drive, Boulder, Colorado 80309-0428, United States
| | - Archish Muralidharan
- Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States
| | - Stephanie J Bryant
- Materials Science and Engineering Program, University of Colorado at Boulder, 4001 Discovery Drive, Boulder, Colorado 80309-613, United States.,Department of Chemical and Biological Engineering, University of Colorado at Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States.,BioFrontiers Institute, University of Colorado at Boulder, 3415 Colorado Avenue, Boulder, Colorado 80309-0596, United States
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25
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Abe K, Baba K, Huang L, Wei KT, Okano K, Hosokawa Y, Inagaki N. Mechanosensitive axon outgrowth mediated by L1-laminin clutch interface. Biophys J 2021; 120:3566-3576. [PMID: 34384760 PMCID: PMC8456307 DOI: 10.1016/j.bpj.2021.08.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/28/2021] [Accepted: 08/04/2021] [Indexed: 11/11/2022] Open
Abstract
Mechanical properties of the extracellular environment modulate axon outgrowth. Growth cones at the tip of extending axons generate traction force for axon outgrowth by transmitting the force of actin filament retrograde flow, produced by actomyosin contraction and F-actin polymerization, to adhesive substrates through clutch and cell adhesion molecules. A molecular clutch between the actin filament flow and substrate is proposed to contribute to cellular mechanosensing. However, the molecular identity of the clutch interface responsible for mechanosensitive growth cone advance is unknown. We previously reported that mechanical coupling between actin filament retrograde flow and adhesive substrates through the clutch molecule shootin1a and the cell adhesion molecule L1 generates traction force for axon outgrowth and guidance. Here, we show that cultured mouse hippocampal neurons extend longer axons on stiffer substrates under elastic conditions that correspond to the soft brain environments. We demonstrate that this stiffness-dependent axon outgrowth requires actin-adhesion coupling mediated by shootin1a, L1, and laminin on the substrate. Speckle imaging analyses showed that L1 at the growth cone membrane switches between two adhesive states: L1 that is immobilized and that undergoes retrograde movement on the substrate. The duration of the immobilized phase was longer on stiffer substrates; this was accompanied by increases in actin-adhesion coupling and in the traction force exerted on the substrate. These data suggest that the interaction between L1 and laminin is enhanced on stiffer substrates, thereby promoting force generation for axon outgrowth.
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Affiliation(s)
- Kouki Abe
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Kentarou Baba
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Liguo Huang
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Koay Teng Wei
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Kazunori Okano
- Bio-processing Engineering Laboratory, Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Yoichiroh Hosokawa
- Bio-processing Engineering Laboratory, Division of Materials Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan.
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26
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Guha S, Mitra MK, Pagonabarraga I, Muhuri S. Novel mechanism for oscillations in catchbonded motor-filament complexes. Biophys J 2021; 120:4129-4136. [PMID: 34329628 DOI: 10.1016/j.bpj.2021.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 04/11/2021] [Accepted: 07/19/2021] [Indexed: 11/26/2022] Open
Abstract
Generation of mechanical oscillations is ubiquitous to a wide variety of intracellular processes ranging from activity of muscle fibres to oscillations of the mitotic spindle. The activity of motors plays a vital role in maintaining the integrity of the mitotic spindle structure and in generating spontaneous oscillations. While the structural features and properties of the individual motors are well characterized, their implications on the functional behaviour of motor-filament complexes is more involved. We show that force-induced allosteric deformations in dynein, which results in catchbonding behaviour, provide a generic mechanism to generate spontaneous oscillations in motor-cytoskeletal filament complexes. The resultant phase diagram of such motor-filament systems - characterized by force-induced allosteric deformations - exhibits bistability and sustained limit cycle oscillations in biologically relevant regimes, such as for catchbonded dynein. The results reported here elucidate the central role of this mechanism in fashioning a distinctive stability behaviour and oscillations in motor-filament complexes, such as mitotic spindles.
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Affiliation(s)
- Sougata Guha
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India; Department of Physics, Savitribai Phule Pune University, Pune, India
| | - Mithun K Mitra
- Department of Physics, Indian Institute of Technology Bombay, Mumbai, India
| | - Ignacio Pagonabarraga
- CECAM, Centre Européen de Calcul Atomique et Moléculaire, École Polytechnique Fédérale de Lasuanne (EPFL), Batochime, Avenue Forel 2, 1015 Lausanne, Switzerland; Departament de Física de la Matèria Condensada, Universitat de Barcelona, Martí i Franquès 1, E08028 Barcelona, Spain; UBICS University of Barcelona Institute of Complex Systems, Martí i Franquès 1, E08028 Barcelona, Spain
| | - Sudipto Muhuri
- Department of Physics, Savitribai Phule Pune University, Pune, India.
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27
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Zakharov A, Dasbiswas K. Modeling mechanochemical pattern formation in elastic sheets of biological matter. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:82. [PMID: 34159454 DOI: 10.1140/epje/s10189-021-00086-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
Inspired by active shape morphing in developing tissues and biomaterials, we investigate two generic mechanochemical models where the deformations of a thin elastic sheet are driven by, and in turn affect, the concentration gradients of a chemical signal. We develop numerical methods to study the coupled elastic deformations and chemical concentration kinetics, and illustrate with computations the formation of different patterns depending on shell thickness, strength of mechanochemical coupling and diffusivity. In the first model, the sheet curvature governs the production of a contractility inhibitor and depending on the threshold in the coupling, qualitatively different patterns occur. The second model is based on the stress-dependent activity of myosin motors and demonstrates how the concentration distribution patterns of molecular motors are affected by the long-range deformations generated by them. Since the propagation of mechanical deformations is typically faster than chemical kinetics (of molecular motors or signaling agents that affect motors), we describe in detail and implement a numerical method based on separation of timescales to effectively simulate such systems. We show that mechanochemical coupling leads to long-range propagation of patterns in disparate systems through elastic instabilities even without the diffusive or advective transport of the chemicals.
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Affiliation(s)
- Andrei Zakharov
- Department of Physics, University of California, Merced, CA, 95343, USA
| | - Kinjal Dasbiswas
- Department of Physics, University of California, Merced, CA, 95343, USA.
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28
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Abstract
Myosin II is a biomolecular machine that is responsible for muscle contraction. Myosin II motors act cooperatively: during muscle contraction, multiple motors bind to a single actin filament and pull it against an external load, like people pulling on a rope in a tug-of-war. We model the dynamics of actomyosin filaments in order to study the evolution of motor-motor cooperativity. We find that filament backsliding-the distance an actin slides backward when a motor at the end of its cycle releases-is central to the speed and efficiency of muscle contraction. Our model predicts that this backsliding has been reduced through evolutionary adaptations to the motor's binding propensity, the strength of the motor's power stroke, and the force dependence of the motor's release from actin. These properties optimize the collective action of myosin II motors, which is not a simple sum of individual motor actions. The model also shows that these evolutionary variables can explain the speed-efficiency trade-off observed across different muscle tissues. This is an example of how evolution can tune the microscopic properties of individual proteins in order to optimize complex biological functions.
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29
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Weirich KL, Stam S, Munro E, Gardel ML. Actin bundle architecture and mechanics regulate myosin II force generation. Biophys J 2021; 120:1957-1970. [PMID: 33798565 DOI: 10.1016/j.bpj.2021.03.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 03/01/2021] [Accepted: 03/12/2021] [Indexed: 10/21/2022] Open
Abstract
The actin cytoskeleton is a soft, structural material that underlies biological processes such as cell division, motility, and cargo transport. The cross-linked actin filaments self-organize into a myriad of architectures, from disordered meshworks to ordered bundles, which are hypothesized to control the actomyosin force generation that regulates cell migration, shape, and adhesion. Here, we use fluorescence microscopy and simulations to investigate how actin bundle architectures with varying polarity, spacing, and rigidity impact myosin II dynamics and force generation. Microscopy reveals that mixed-polarity bundles formed by rigid cross-linkers support slow, bidirectional myosin II filament motion, punctuated by periods of stalled motion. Simulations reveal that these locations of stalled myosin motion correspond to sustained, high forces in regions of balanced actin filament polarity. By contrast, mixed-polarity bundles formed by compliant, large cross-linkers support fast, bidirectional motion with no traps. Simulations indicate that trap duration is directly related to force magnitude and that the observed increased velocity corresponds to lower forces resulting from both the increased bundle compliance and filament spacing. Our results indicate that the microstructures of actin assemblies regulate the dynamics and magnitude of myosin II forces, highlighting the importance of architecture and mechanics in regulating forces in biological materials.
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Affiliation(s)
- Kimberly L Weirich
- James Franck Institute, University of Chicago, Chicago, Illinois; Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois; Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina
| | - Samantha Stam
- Biophysical Sciences Graduate Program, University of Chicago, Chicago, Illinois; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois; Department of Molecular and Cellular Biology, University of California, Davis, Davis, California
| | - Edwin Munro
- Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois; Department of Molecular Genetics and Cellular Biology, University of Chicago, Chicago, Illinois
| | - Margaret L Gardel
- James Franck Institute, University of Chicago, Chicago, Illinois; Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois; Institute for Biophysical Dynamics, University of Chicago, Chicago, Illinois; Department of Physics, University of Chicago, Chicago, Illinois.
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30
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A Fully Integrated Arduino-Based System for the Application of Stretching Stimuli to Living Cells and Their Time-Lapse Observation: A Do-It-Yourself Biology Approach. Ann Biomed Eng 2021; 49:2243-2259. [PMID: 33728867 DOI: 10.1007/s10439-021-02758-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/20/2021] [Indexed: 10/21/2022]
Abstract
Mechanobiology has nowadays acquired the status of a topic of fundamental importance in a degree in Biological Sciences. It is inherently a multidisciplinary topic where biology, physics and engineering competences are required. A course in mechanobiology should include lab experiences where students can appreciate how mechanical stimuli from outside affect living cell behaviour. Here we describe all the steps to build a cell stretcher inside an on-stage cell incubator. This device allows exposing living cells to a periodic mechanical stimulus similar to what happens in physiological conditions such as, for example, in the vascular system or in the lungs. The reaction of the cells to the periodic mechanical stretching represents a prototype of a mechanobiological signal integrated by living cells. We also provide the theoretical and experimental aspects related to the calibration of the stretcher apparatus at a level accessible to researchers not used to dealing with topics like continuum mechanics and analysis of deformations. We tested our device by stretching cells of two different lines, U87-MG and Balb-3T3 cells, and we analysed and discussed the effect of the periodic stimulus on both cell reorientation and migration. We also discuss the basic aspects related to the quantitative analysis of the reorientation process and of cell migration. We think that the device we propose can be easily reproduced at low-cost within a project-oriented course in the fields of biology, biotechnology and medical engineering.
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31
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Tabatabai AP, Seara DS, Tibbs J, Yadav V, Linsmeier I, Murrell MP. Detailed Balance Broken by Catch Bond Kinetics Enables Mechanical-Adaptation in Active Materials. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2006745. [PMID: 34393691 PMCID: PMC8357268 DOI: 10.1002/adfm.202006745] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Indexed: 05/04/2023]
Abstract
Unlike nearly all engineered materials which contain bonds that weaken under load, biological materials contain "catch" bonds which are reinforced under load. Consequently, materials, such as the cell cytoskeleton, can adapt their mechanical properties in response to their state of internal, non-equilibrium (active) stress. However, how large-scale material properties vary with the distance from equilibrium is unknown, as are the relative roles of active stress and binding kinetics in establishing this distance. Through course-grained molecular dynamics simulations, the effect of breaking of detailed balance by catch bonds on the accumulation and dissipation of energy within a model of the actomyosin cytoskeleton is explored. It is found that the extent to which detailed balance is broken uniquely determines a large-scale fluid-solid transition with characteristic time-reversal symmetries. The transition depends critically on the strength of the catch bond, suggesting that active stress is necessary but insufficient to mount an adaptive mechanical response.
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Affiliation(s)
- Alan Pasha Tabatabai
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Daniel S Seara
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA
| | - Joseph Tibbs
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Vikrant Yadav
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Ian Linsmeier
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06511, USA; Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA; Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06511, USA
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32
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Dansuk KC, Keten S. Self-strengthening biphasic nanoparticle assemblies with intrinsic catch bonds. Nat Commun 2021; 12:85. [PMID: 33397979 PMCID: PMC7782701 DOI: 10.1038/s41467-020-20344-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 11/23/2020] [Indexed: 01/06/2023] Open
Abstract
Protein-ligand complexes with catch bonds exhibit prolonged lifetimes when subject to tensile force, which is a desirable yet elusive attribute for man-made nanoparticle interfaces and assemblies. Most designs proposed so far rely on macromolecular linkers with complicated folds rather than particles exhibiting simple dynamic shapes. Here, we establish a scissor-type X-shaped particle design for achieving intrinsic catch bonding ability with tunable force-enhanced lifetimes under thermal excitations. Molecular dynamics simulations are carried out to illustrate equilibrium self-assembly and force-enhanced bond lifetime of dimers and fibers facilitated by secondary interactions that form under tensile force. The non-monotonic force dependence of the fiber breaking kinetics is well-estimated by an analytical model. Our design concepts for shape-changing particles illuminates a path towards novel nanoparticle or colloidal assemblies that have the passive ability to tune the strength of their interfaces with applied force, setting the stage for self-assembling materials with novel mechanical functions and rheological properties.
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Affiliation(s)
- Kerim C Dansuk
- Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA
| | - Sinan Keten
- Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
- Department of Civil & Environmental Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208, USA.
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33
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Bond Type and Discretization of Nonmuscle Myosin II Are Critical for Simulated Contractile Dynamics. Biophys J 2020; 118:2703-2717. [PMID: 32365328 DOI: 10.1016/j.bpj.2020.03.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 02/18/2020] [Accepted: 03/03/2020] [Indexed: 12/22/2022] Open
Abstract
Molecular motors drive cytoskeletal rearrangements to change cell shape. Myosins are the motors that move, cross-link, and modify the actin cytoskeleton. The primary force generator in contractile actomyosin networks is nonmuscle myosin II (NMMII), a molecular motor that assembles into ensembles that bind, slide, and cross-link actin filaments (F-actin). The multivalence of NMMII ensembles and their multiple roles have confounded the resolution of crucial questions, including how the number of NMMII subunits affects dynamics and what affects the relative contribution of ensembles' cross-linking versus motoring activities. Because biophysical measurements of ensembles are sparse, modeling of actomyosin networks has aided in discovering the complex behaviors of NMMII ensembles. Myosin ensembles have been modeled via several strategies with variable discretization or coarse graining and unbinding dynamics, and although general assumptions that simplify motor ensembles result in global contractile behaviors, it remains unclear which strategies most accurately depict cellular activity. Here, we used an agent-based platform, Cytosim, to implement several models of NMMII ensembles. Comparing the effects of bond type, we found that ensembles of catch-slip and catch motors were the best force generators and binders of filaments. Slip motor ensembles were capable of generating force but unbound frequently, resulting in slower contractile rates of contractile networks. Coarse graining of these ensemble types from two sets of 16 motors on opposite ends of a stiff rod to two binders, each representing 16 motors, reduced force generation, contractility, and the total connectivity of filament networks for all ensemble types. A parallel cluster model, previously used to describe ensemble dynamics via statistical mechanics, allowed better contractility with coarse graining, though connectivity was still markedly reduced for this ensemble type with coarse graining. Together, our results reveal substantial tradeoffs associated with the process of coarse graining NMMII ensembles and highlight the robustness of discretized catch-slip ensembles in modeling actomyosin networks.
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34
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Zhu C, Lee CY, McIntire LV. From cellular to molecular mechanobiology. APL Bioeng 2020; 4:010902. [PMID: 32095735 PMCID: PMC7021513 DOI: 10.1063/1.5129937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 01/03/2020] [Indexed: 12/15/2022] Open
Abstract
Mechanobiology at the cellular level is concerned with what phenotypes that cells exhibit to maintain homeostasis in their normal physiological mechanical environment, as well as what phenotypical changes that cells have to make when their environment is altered. Mechanobiology at the molecular level aims to understand the molecular underpinning of how cells sense, respond to, and adapt to mechanical cues in their environment. In this Perspective, we use our work inspired by and in collaboration with Professor Shu Chien as an example with which we connect the mechanobiology between the cellular and molecular levels. We discuss how physical forces acting on intracellular proteins may impact protein-protein interaction, change protein conformation, crosstalk with biochemical signaling molecules, induce mechanotransduction, and alter the cell structure and function.
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Affiliation(s)
- Cheng Zhu
- Author to whom correspondence should be addressed:
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35
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Jung W, Fillenwarth LA, Matsuda A, Li J, Inoue Y, Kim T. Collective and contractile filament motions in the myosin motility assay. SOFT MATTER 2020; 16:1548-1559. [PMID: 31942899 PMCID: PMC7342887 DOI: 10.1039/c9sm02082a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Cells require mechanical forces for their physiological functions. The forces are generated mainly from molecular interactions between actin filaments, cross-linking proteins, and myosin motors in the actin cytoskeleton. To better understand the molecular interactions, many studies employed myosin motility assays with actin filaments propelled by myosin heads fixed on a surface. Various interesting behaviors of actin filaments have been observed in the motility assay experiments. Despite the popularity of the motility assays, there were only a few computational models designed for simulating the motility assay systems. Most of the previous models have limitations which precluded full understanding of molecular origins for behaviors of actin filaments. In this study, we used an agent-based computational model based on Brownian dynamics for simulating the motility assay system. Our model rigorously describes the mechanics, dynamics, and interactions of actin filaments, cross-linking proteins, and molecular motors. Using the model, we first investigated how properties of actin filaments and motors affect gliding motions of actin filaments without volume-exclusion effects as a base study. We found that actin filaments can continuously glide at relative fast speed only when they are sufficiently longer than the average spacing between neighboring motors and that the gliding speed of F-actins shows a biphasic dependence on processivity of motors. Then, we showed that volume-exclusion effects between actin filaments can induce diverse collective movements and alignment of actin filaments, thus creating thick bundles and ring-like structures in the absence of cross-linking proteins. Lastly, we demonstrated that cross-linking proteins can lead to distinct contractile behaviors of actin networks depending on the density and kinetics of the cross-linking proteins. Results from our study show the ability of our model to simulate the motility assay system under various conditions and provide insights into understanding of different behaviors of actin filaments.
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Affiliation(s)
- Wonyeong Jung
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, IN 47907, USA.
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36
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Ezber Y, Belyy V, Can S, Yildiz A. Dynein Harnesses Active Fluctuations of Microtubules for Faster Movement. NATURE PHYSICS 2020; 16:312-316. [PMID: 33868446 PMCID: PMC8049612 DOI: 10.1038/s41567-019-0757-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 11/15/2019] [Indexed: 06/11/2023]
Abstract
The cytoskeleton forms a dynamic network that generates fluctuations larger than thermal agitation of the cytoplasm1. Here, we tested whether dynein, a minus-end-directed microtubule (MT) motor2, can harness energy from these fluctuations using optical trapping in vitro. We show that dynein forms an asymmetric slip bond with MTs, where its detachment rate increases more slowly under hindering forces than assisting forces. This asymmetry enables dynein to generate unidirectional motility towards the minus-end from force fluctuations. Consistent with our model, oscillatory forces exerted by the trap drive dynein stepping without net force and ATP. Dynein is capable of ratcheting towards the minus-end even when the net force is in the plus-end direction. With ATP, force oscillations increase the velocity and stall force of dynein as it transports cargos and glides MTs. Therefore, dynein is a mechanical ratchet that rectifies cytoskeletal fluctuations to move faster and resists higher forces along MTs.
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Affiliation(s)
- Yasin Ezber
- Physics Department, University of California, Berkeley CA 94720 USA
| | - Vladislav Belyy
- Biophysics Graduate Group, University of California, Berkeley CA 94720 USA
| | - Sinan Can
- Physics Department, University of California, Berkeley CA 94720 USA
| | - Ahmet Yildiz
- Physics Department, University of California, Berkeley CA 94720 USA
- Biophysics Graduate Group, University of California, Berkeley CA 94720 USA
- The Department of Molecular and Cellular Biology, University of California, Berkeley CA 94720 USA
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37
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Zhu C, Chen Y, Ju LA. Dynamic bonds and their roles in mechanosensing. Curr Opin Chem Biol 2019; 53:88-97. [PMID: 31563813 PMCID: PMC6926149 DOI: 10.1016/j.cbpa.2019.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 07/14/2019] [Accepted: 08/22/2019] [Indexed: 12/25/2022]
Abstract
Mechanical forces are ubiquitous in a cell's internal structure and external environment. Mechanosensing is the process that the cell employs to sense its mechanical environment. In receptor-mediated mechanosensing, cell surface receptors interact with immobilized ligands to provide a specific way to receive extracellular force signals to targeted force-transmitting, force-transducing and force-supporting structures inside the cell. Conversely, forces generated endogenously by the cell can be transmitted via cytoplasmic protein-protein interactions and regulate cell surface receptor activities in an 'inside-out' manner. Dynamic force spectroscopy analyzes these interactions on and inside cells to reveal various dynamic bonds. What is more, by integrating analysis of molecular interactions with that of cell signaling events involved in force-sensing and force-responding processes, one can investigate how dynamic bonds regulate the reception, transmission and transduction of mechanical signals.
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Affiliation(s)
- Cheng Zhu
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Yunfeng Chen
- Department of Molecular Medicine, MERU-Roon Research Center on Vascular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Lining Arnold Ju
- School of Biomedical Engineering, The University of Sydney, Camperdown, NSW 2006, Australia; Charles Perkins Centre, The University of Sydney, Camperdown, NSW 2006, Australia; Heart Research Institute, The University of Sydney, Camperdown, NSW 2006, Australia
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38
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Osório DS, Chan FY, Saramago J, Leite J, Silva AM, Sobral AF, Gassmann R, Carvalho AX. Crosslinking activity of non-muscle myosin II is not sufficient for embryonic cytokinesis in C. elegans. Development 2019; 146:dev.179150. [PMID: 31582415 PMCID: PMC6857588 DOI: 10.1242/dev.179150] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 09/23/2019] [Indexed: 11/21/2022]
Abstract
Cytokinesis in animal cells requires the assembly and constriction of a contractile actomyosin ring. Non-muscle myosin II is essential for cytokinesis, but the role of its motor activity remains unclear. Here, we examine cytokinesis in C. elegans embryos expressing non-muscle myosin motor mutants generated by genome editing. Two non-muscle motor-dead myosins capable of binding F-actin do not support cytokinesis in the one-cell embryo, and two partially motor-impaired myosins delay cytokinesis and render rings more sensitive to reduced myosin levels. Further analysis of myosin mutants suggests that it is myosin motor activity, and not the ability of myosin to crosslink F-actin, that drives the alignment and compaction of F-actin bundles during contractile ring assembly, and that myosin motor activity sets the pace of contractile ring constriction. We conclude that myosin motor activity is required at all stages of cytokinesis. Finally, characterization of the corresponding motor mutations in C. elegans major muscle myosin shows that motor activity is required for muscle contraction but is dispensable for F-actin organization in adult muscles. This article has an associated ‘The people behind the papers’ interview. Highlighted Article: The motor activity of non-muscle myosin II is essential for cytokinesis and contributes to all stages of the process in C. elegans embryos.
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Affiliation(s)
- Daniel S Osório
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal .,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Fung-Yi Chan
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Joana Saramago
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Joana Leite
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana M Silva
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F Sobral
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Reto Gassmann
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana Xavier Carvalho
- Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, 4200-135 Porto, Portugal .,Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal
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39
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Dahlke K, Zhao J, Sing CE, Banigan EJ. Force-Dependent Facilitated Dissociation Can Generate Protein-DNA Catch Bonds. Biophys J 2019; 117:1085-1100. [PMID: 31427067 DOI: 10.1016/j.bpj.2019.07.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/08/2019] [Accepted: 07/29/2019] [Indexed: 12/31/2022] Open
Abstract
Cellular structures are continually subjected to forces, which may serve as mechanical signals for cells through their effects on biomolecule interaction kinetics. Typically, molecular complexes interact via "slip bonds," so applied forces accelerate off rates by reducing transition energy barriers. However, biomolecules with multiple dissociation pathways may have considerably more complicated force dependencies. This is the case for DNA-binding proteins that undergo "facilitated dissociation," in which competitor biomolecules from solution enhance molecular dissociation in a concentration-dependent manner. Using simulations and theory, we develop a generic model that shows that proteins undergoing facilitated dissociation can form an alternative type of molecular bond, known as a "catch bond," for which applied forces suppress protein dissociation. This occurs because the binding by protein competitors responsible for the facilitated dissociation pathway can be inhibited by applied forces. Within the model, we explore how the force dependence of dissociation is regulated by intrinsic factors, including molecular sensitivity to force and binding geometry and the extrinsic factor of competitor protein concentration. We find that catch bonds generically emerge when the force dependence of the facilitated unbinding pathway is stronger than that of the spontaneous unbinding pathway. The sharpness of the transition between slip- and catch-bond kinetics depends on the degree to which the protein bends its DNA substrate. This force-dependent kinetics is broadly regulated by the concentration of competitor biomolecules in solution. Thus, the observed catch bond is mechanistically distinct from other known physiological catch bonds because it requires an extrinsic factor-competitor proteins-rather than a specific intrinsic molecular structure. We hypothesize that this mechanism for regulating force-dependent protein dissociation may be used by cells to modulate protein exchange, regulate transcription, and facilitate diffusive search processes.
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Affiliation(s)
- Katelyn Dahlke
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jing Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Charles E Sing
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois.
| | - Edward J Banigan
- Institute for Medical Engineering and Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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40
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Shams H, Hoffman BD, Mofrad MRK. The "Stressful" Life of Cell Adhesion Molecules: On the Mechanosensitivity of Integrin Adhesome. J Biomech Eng 2019; 140:2667887. [PMID: 29272321 DOI: 10.1115/1.4038812] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Indexed: 02/06/2023]
Abstract
Cells have evolved into complex sensory machines that communicate with their microenvironment via mechanochemical signaling. Extracellular mechanical cues trigger complex biochemical pathways in the cell, which regulate various cellular processes. Integrin-mediated focal adhesions (FAs) are large multiprotein complexes, also known as the integrin adhesome, that link the extracellular matrix (ECM) to the actin cytoskeleton, and are part of powerful intracellular machinery orchestrating mechanotransduction pathways. As forces are transmitted across FAs, individual proteins undergo structural and functional changes that involve a conversion of chemical to mechanical energy. The local composition of early adhesions likely defines the regional stress levels and determines the type of newly recruited proteins, which in turn modify the local stress distribution. Various approaches have been used for detecting and exploring molecular mechanisms through which FAs are spatiotemporally regulated, however, many aspects are yet to be understood. Current knowledge on the molecular mechanisms of mechanosensitivity in adhesion proteins is discussed herein along with important questions yet to be addressed, are discussed.
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Affiliation(s)
- Hengameh Shams
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, CA 94720-1762
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, 208A Stanley Hall #1762, Berkeley, CA 94720-1762.,Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, CA 94720 e-mail:
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41
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Matsuda A, Li J, Brumm P, Adachi T, Inoue Y, Kim T. Mobility of Molecular Motors Regulates Contractile Behaviors of Actin Networks. Biophys J 2019; 116:2161-2171. [PMID: 31103238 DOI: 10.1016/j.bpj.2019.04.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 03/04/2019] [Accepted: 04/15/2019] [Indexed: 12/18/2022] Open
Abstract
Cells generate mechanical forces primarily from interactions between F-actin, cross-linking proteins, myosin motors, and other actin-binding proteins in the cytoskeleton. To understand how molecular interactions between the cytoskeletal elements generate forces, a number of in vitro experiments have been performed but are limited in their ability to accurately reproduce the diversity of motor mobility. In myosin motility assays, myosin heads are fixed on a surface and glide F-actin. By contrast, in reconstituted gels, the motion of both myosin and F-actin is unrestricted. Because only these two extreme conditions have been used, the importance of mobility of motors for network behaviors has remained unclear. In this study, to illuminate the impacts of motor mobility on the contractile behaviors of the actin cytoskeleton, we employed an agent-based computational model based on Brownian dynamics. We find that if motors can bind to only one F-actin like myosin I, networks are most contractile at intermediate mobility. In this case, less motor mobility helps motors stably pull F-actins to generate tensile forces, whereas higher motor mobility allows F-actins to aggregate into larger clustering structures. The optimal intermediate motor mobility depends on the stall force and affinity of motors that are regulated by mechanochemical rates. In addition, we find that the role of motor mobility can vary drastically if motors can bind to a pair of F-actins. A network can exhibit large contraction with high motor mobility because motors bound to antiparallel pairs of F-actins can exert similar forces regardless of their mobility. Results from this study imply that the mobility of molecular motors may critically regulate contractile behaviors of actin networks in cells.
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Affiliation(s)
- Atsushi Matsuda
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Kyoto, Japan
| | - Jing Li
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Peter Brumm
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
| | - Taiji Adachi
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Kyoto, Japan
| | - Yasuhiro Inoue
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Kyoto, Japan.
| | - Taeyoon Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana.
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42
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Rahikainen R, Öhman T, Turkki P, Varjosalo M, Hytönen VP. Talin-mediated force transmission and talin rod domain unfolding independently regulate adhesion signaling. J Cell Sci 2019; 132:jcs226514. [PMID: 30837291 DOI: 10.1242/jcs.226514] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/26/2019] [Indexed: 12/29/2022] Open
Abstract
Talin protein is one of the key components in integrin-mediated adhesion complexes. Talins transmit mechanical forces between β-integrin and actin, and regulate adhesion complex composition and signaling through the force-regulated unfolding of talin rod domain. Using modified talin proteins, we demonstrate that these functions contribute to different cellular processes and can be dissected. The transmission of mechanical forces regulates adhesion complex composition and phosphotyrosine signaling even in the absence of the mechanically regulated talin rod subdomains. However, the presence of the rod subdomains and their mechanical activation are required for the reinforcement of the adhesion complex, cell polarization and migration. Talin rod domain unfolding was also found to be essential for the generation of cellular signaling anisotropy, since both insufficient and excess activity of the rod domain severely inhibited cell polarization. Utilizing proteomics tools, we identified adhesome components that are recruited and activated either in a talin rod-dependent manner or independently of the rod subdomains. This study clarifies the division of roles between the force-regulated unfolding of a talin protein (talin 1) and its function as a physical linker between integrins and the cytoskeleton.
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Affiliation(s)
- Rolle Rahikainen
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
| | - Tiina Öhman
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Paula Turkki
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Vesa P Hytönen
- Faculty of Medicine and Health Technology and BioMediTech, Tampere University, Tampere 33014, Finland
- Fimlab Laboratories, Tampere 33520, Finland
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43
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Harrison DL, Fang Y, Huang J. T-Cell Mechanobiology: Force Sensation, Potentiation, and Translation. FRONTIERS IN PHYSICS 2019; 7:45. [PMID: 32601597 PMCID: PMC7323161 DOI: 10.3389/fphy.2019.00045] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A T cell is a sensitive self-referential mechanical sensor. Mechanical forces influence the recognition, activation, differentiation, and function throughout the lifetime of a T cell. T cells constantly perceive and respond to physical stimuli through their surface receptors, cytoskeleton, and subcellular structures. Surface receptors receive physical cues in the form of forces generated through receptor-ligand binding events, which are dynamically regulated by contact tension, shear stress, and substrate rigidity. The resulting mechanotransduction not only influences T-cell recognition and signaling but also possibly modulates cell metabolism and gene expression. Moreover, forces also dynamically regulate the deformation, organization, and translocation of cytoskeleton and subcellular structures, leading to changes in T-cell mobility, migration, and infiltration. However, the roles and mechanisms of how mechanical forces modulate T-cell recognition, signaling, metabolism, and gene expression, are largely unknown and underappreciated. Here, we review recent technological and scientific advances in T-cell mechanobiology, discuss possible roles and mechanisms of T-cell mechanotransduction, and propose new research directions of this emerging field in health and disease.
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Affiliation(s)
- Devin L. Harrison
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
| | - Yun Fang
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
- Section of Pulmonary and Critical Care, Department of Medicine, The University of Chicago, Chicago, IL, United States
| | - Jun Huang
- The Graduate Program in Biophysical Sciences, The University of Chicago, Chicago, IL, United States
- Institute for Molecular Engineering, The University of Chicago, Chicago, IL, United States
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44
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Lee H, Eskin SG, Ono S, Zhu C, McIntire LV. Force-history dependence and cyclic mechanical reinforcement of actin filaments at the single molecular level. J Cell Sci 2019; 132:jcs.216911. [PMID: 30659118 DOI: 10.1242/jcs.216911] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 01/03/2019] [Indexed: 01/02/2023] Open
Abstract
The actin cytoskeleton is subjected to dynamic mechanical forces over time and the history of force loading may serve as mechanical preconditioning. While the actin cytoskeleton is known to be mechanosensitive, the mechanisms underlying force regulation of actin dynamics still need to be elucidated. Here, we investigated actin depolymerization under a range of dynamic tensile forces using atomic force microscopy. Mechanical loading by cyclic tensile forces induced significantly enhanced bond lifetimes and different force-loading histories resulted in different dissociation kinetics in G-actin-G-actin and G-actin-F-actin interactions. Actin subunits at the two ends of filaments formed bonds with distinct kinetics under dynamic force, with cyclic mechanical reinforcement more effective at the pointed end compared to that at the barbed end. Our data demonstrate force-history dependent reinforcement in actin-actin bonds and polarity of the actin depolymerization kinetics under cyclic tensile forces. These properties of actin may be important clues to understanding regulatory mechanisms underlying actin-dependent mechanotransduction and mechanosensitive cytoskeletal dynamics.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Hyunjung Lee
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Suzanne G Eskin
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Shoichiro Ono
- Departments of Pathology and Cell Biology, Emory University, Atlanta, GA 30322, USA .,Winship Cancer Institute, Emory University, Atlanta, GA 30322, USA
| | - Cheng Zhu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA .,Geroge W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Larry V McIntire
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
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45
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Caruel M, Moireau P, Chapelle D. Stochastic modeling of chemical–mechanical coupling in striated muscles. Biomech Model Mechanobiol 2019; 18:563-587. [DOI: 10.1007/s10237-018-1102-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 11/21/2018] [Indexed: 01/15/2023]
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46
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Cortes DB, Dawes A, Liu J, Nickaeen M, Strychalski W, Maddox AS. Unite to divide - how models and biological experimentation have come together to reveal mechanisms of cytokinesis. J Cell Sci 2018; 131:131/24/jcs203570. [PMID: 30563924 DOI: 10.1242/jcs.203570] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cytokinesis is the fundamental and ancient cellular process by which one cell physically divides into two. Cytokinesis in animal and fungal cells is achieved by contraction of an actomyosin cytoskeletal ring assembled in the cell cortex, typically at the cell equator. Cytokinesis is essential for the development of fertilized eggs into multicellular organisms and for homeostatic replenishment of cells. Correct execution of cytokinesis is also necessary for genome stability and the evasion of diseases including cancer. Cytokinesis has fascinated scientists for well over a century, but its speed and dynamics make experiments challenging to perform and interpret. The presence of redundant mechanisms is also a challenge to understand cytokinesis, leaving many fundamental questions unresolved. For example, how does a disordered cytoskeletal network transform into a coherent ring? What are the long-distance effects of localized contractility? Here, we provide a general introduction to 'modeling for biologists', and review how agent-based modeling and continuum mechanics modeling have helped to address these questions.
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Affiliation(s)
- Daniel B Cortes
- Department of Biology, University of North Carolina at Chapel Hill, 407 Fordham Hall, Chapel Hill, NC 27599, USA
| | - Adriana Dawes
- Departments of Mathematics and of Molecular Genetics, The Ohio State University, 100 Math Tower, 231 West 18th Avenue, Columbus, OH 43210, USA
| | - Jian Liu
- National Heart, Lung and Blood Institute, Biochemistry and Biophysics Center, 50 South Drive, NIH, Bethesda, MD 20892, USA
| | - Masoud Nickaeen
- Richard D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center, Department of Cell Biology, 263 Farmington Avenue, Farmington, CT 06030-6406, USA
| | - Wanda Strychalski
- Department of Mathematics, Applied Mathematics, and Statistics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA
| | - Amy Shaub Maddox
- Department of Biology, University of North Carolina at Chapel Hill, 407 Fordham Hall, Chapel Hill, NC 27599, USA
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47
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Månsson A, Persson M, Shalabi N, Rassier DE. Nonlinear Actomyosin Elasticity in Muscle? Biophys J 2018; 116:330-346. [PMID: 30606448 PMCID: PMC6350078 DOI: 10.1016/j.bpj.2018.12.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/24/2018] [Accepted: 12/05/2018] [Indexed: 12/12/2022] Open
Abstract
Cyclic interactions between myosin II motor domains and actin filaments that are powered by turnover of ATP underlie muscle contraction and have key roles in motility of nonmuscle cells. The elastic characteristics of actin-myosin cross-bridges are central in the force-generating process, and disturbances in these properties may lead to disease. Although the prevailing paradigm is that the cross-bridge elasticity is linear (Hookean), recent single-molecule studies suggest otherwise. Despite convincing evidence for substantial nonlinearity of the cross-bridge elasticity in the single-molecule work, this finding has had limited influence on muscle physiology and physiology of other ordered cellular actin-myosin ensembles. Here, we use a biophysical modeling approach to close the gap between single molecules and physiology. The model is used for analysis of available experimental results in the light of possible nonlinearity of the cross-bridge elasticity. We consider results obtained both under rigor conditions (in the absence of ATP) and during active muscle contraction. Our results suggest that a wide range of experimental findings from mechanical experiments on muscle cells are consistent with nonlinear actin-myosin elasticity similar to that previously found in single molecules. Indeed, the introduction of nonlinear cross-bridge elasticity into the model improves the reproduction of key experimental results and eliminates the need for force dependence of the ATP-induced detachment rate, consistent with observations in other single-molecule studies. The findings have significant implications for the understanding of key features of actin-myosin-based production of force and motion in living cells, particularly in muscle, and for the interpretation of experimental results that rely on stiffness measurements on cells or myofibrils.
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Affiliation(s)
- Alf Månsson
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden.
| | - Malin Persson
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden; Department of Kinesiology and Physical Education, McGill University, Montreal, Canada; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Nabil Shalabi
- Department of Kinesiology and Physical Education, McGill University, Montreal, Canada
| | - Dilson E Rassier
- Department of Kinesiology and Physical Education, McGill University, Montreal, Canada
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48
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Exploring the Sulfatase 1 Catch Bond Free Energy Landscape using Jarzynski's Equality. Sci Rep 2018; 8:16849. [PMID: 30442949 PMCID: PMC6237999 DOI: 10.1038/s41598-018-35120-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/25/2018] [Indexed: 01/29/2023] Open
Abstract
In non-covalent biological adhesion, molecular bonds commonly exhibit a monotonously decreasing life time when subjected to tensile forces (slip bonds). In contrast, catch bonds behave counter intuitively, as they show an increased life time within a certain force interval. To date only a hand full of catch bond displaying systems have been identified. In order to unveil their nature, a number of structural and phenomenological models have been introduced. Regardless of the individual causes for catch bond behavior, it appears evident that the free energy landscapes of these interactions bear more than one binding state. Here, we investigated the catch bond interaction between the hydrophilic domain of the human cell surface sulfatase 1 (Sulf1HD) and its physiological substrate heparan sulfate (HS) by atomic force microscopy based single molecule force spectroscopy (AFM-SMFS). Using Jarzynski’s equality, we estimated the associated Gibbs free energy and provide a comprehensive thermodynamic and kinetic characterization of Sulf1HD/HS interaction. Interestingly, the binding potential landscape exhibits two distinct potential wells which confirms the recently suggested two state binding. Even though structural data of Sulf1HD is lacking, our results allow to draft a detailed picture of the directed and processive desulfation of HS.
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49
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Bernheim-Groswasser A, Gov NS, Safran SA, Tzlil S. Living Matter: Mesoscopic Active Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1707028. [PMID: 30256463 DOI: 10.1002/adma.201707028] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/27/2018] [Indexed: 06/08/2023]
Abstract
An introduction to the physical properties of living active matter at the mesoscopic scale (tens of nanometers to micrometers) and their unique features compared with "dead," nonactive matter is presented. This field of research is increasingly denoted as "biological physics" where physics includes chemical physics, soft matter physics, hydrodynamics, mechanics, and the related engineering sciences. The focus is on the emergent properties of these systems and their collective behavior, which results in active self-organization and how they relate to cellular-level biological function. These include locomotion (cell motility and migration) forces that give rise to cell division, the growth and form of cellular assemblies in development, the beating of heart cells, and the effects of mechanical perturbations such as shear flow (in the bloodstream) or adhesion to other cells or tissues. An introduction to the fundamental concepts and theory with selected experimental examples related to the authors' own research is presented, including red-blood-cell membrane fluctuations, motion of the nucleus within an egg cell, self-contracting acto-myosin gels, and structure and beating of heart cells (cardiomyocytes), including how they can be driven by an oscillating, mechanical probe.
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Affiliation(s)
- Anne Bernheim-Groswasser
- Department of Chemical Engineering and Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva, 84105, Israel
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Samuel A Safran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Shelly Tzlil
- Department of Mechanical Engineering, Technion, Haifa, 3200003, Israel
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50
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Adhikari S, Moran J, Weddle C, Hinczewski M. Unraveling the mechanism of the cadherin-catenin-actin catch bond. PLoS Comput Biol 2018; 14:e1006399. [PMID: 30118477 PMCID: PMC6114904 DOI: 10.1371/journal.pcbi.1006399] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/29/2018] [Accepted: 07/24/2018] [Indexed: 11/19/2022] Open
Abstract
The adherens junctions between epithelial cells involve a protein complex formed by E-cadherin, β-catenin, α-catenin and F-actin. The stability of this complex was a puzzle for many years, since in vitro studies could reconstitute various stable subsets of the individual proteins, but never the entirety. The missing ingredient turned out to be mechanical tension: a recent experiment that applied physiological forces to the complex with an optical tweezer dramatically increased its lifetime, a phenomenon known as catch bonding. However, in the absence of a crystal structure for the full complex, the microscopic details of the catch bond mechanism remain mysterious. Building on structural clues that point to α-catenin as the force transducer, we present a quantitative theoretical model for how the catch bond arises, fully accounting for the experimental lifetime distributions. The underlying hypothesis is that force induces a rotational transition between two conformations of α-catenin, overcoming a significant energy barrier due to a network of salt bridges. This transition allosterically regulates the energies at the interface between α-catenin and F-actin. The model allows us to predict these energetic changes, as well as highlighting the importance of the salt bridge rotational barrier. By stabilizing one of the α-catenin states, this barrier could play a role in how the complex responds to additional in vivo binding partners like vinculin. Since significant conformational energy barriers are a common feature of other adhesion systems that exhibit catch bonds, our model can be adapted into a general theoretical framework for integrating structure and function in a variety of force-regulated protein complexes.
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Affiliation(s)
- Shishir Adhikari
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jacob Moran
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Christopher Weddle
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Michael Hinczewski
- Department of Physics, Case Western Reserve University, Cleveland, Ohio, United States of America
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