1
|
Dolgitzer D, Plaza-Rodríguez AI, Iglesias MA, Jacob MAC, Todd BA, Robinson DN, Iglesias PA. A continuum model of mechanosensation based on contractility kit assembly. Biophys J 2025; 124:62-76. [PMID: 39521955 PMCID: PMC11739882 DOI: 10.1016/j.bpj.2024.10.020] [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: 07/30/2024] [Revised: 10/07/2024] [Accepted: 10/30/2024] [Indexed: 11/16/2024] Open
Abstract
The ability of cells to sense and respond to mechanical forces is crucial for navigating their environment and interacting with neighboring cells. Myosin II and cortexillin I form complexes known as contractility kits (CKs) in the cytosol, which facilitate a cytoskeletal response by accumulating locally at the site of inflicted stress. Here, we present a computational model for mechanoresponsiveness in Dictyostelium, analyzing the role of CKs within the mechanoresponsive mechanism grounded in experimentally measured parameters. Our model further elaborates on the established distributions and channeling of contractile proteins before and after mechanical force application. We rigorously validate our computational findings by comparing the responses of wild-type cells, null mutants, overexpression mutants, and cells deficient in CK formation to mechanical stresses. Parallel in vivo experiments measuring myosin II cortical distributions at equilibrium provide additional validation. Our results highlight the essential functions of CKs in cellular mechanosensitivity and suggest new insights into the regulatory dynamics of mechanoresponsiveness.
Collapse
Affiliation(s)
- David Dolgitzer
- Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, Maryland.
| | - Alma I Plaza-Rodríguez
- Oncology-Quantitative Sciences Department, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Miguel A Iglesias
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey
| | - Mark Allan C Jacob
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Bethany A Todd
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Douglas N Robinson
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Pablo A Iglesias
- Department of Cell Biology, The Johns Hopkins School of Medicine, Baltimore, Maryland; Department of Electrical and Computer Engineering, Whiting School of Engineering, The Johns Hopkins University, Baltimore, Maryland.
| |
Collapse
|
2
|
Sakamoto R, Murrell MP. Mechanical power is maximized during contractile ring-like formation in a biomimetic dividing cell model. Nat Commun 2024; 15:9731. [PMID: 39523366 PMCID: PMC11551154 DOI: 10.1038/s41467-024-53228-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Accepted: 10/07/2024] [Indexed: 11/16/2024] Open
Abstract
The spatial and temporal dynamics of forces in cells coordinate essential behaviors like division, polarization, and migration. While intracellular signaling initiates contractile ring assembly during cell division, how mechanical forces coordinate division and their energetic costs remain unclear. Here, we develop an in vitro model where myosin-induced stress drives division-like shape changes in giant unilamellar vesicles (GUVs, liposomes). Myosin activity is controlled by light patterns globally or locally at the equator. Global activation causes slow, shallow cleavage furrows due to a tug-of-war between the equatorial and polar forces. By contrast, local activation leads to faster, deeper, and symmetric division as equatorial forces dominate. Dissociating the actin cortex at the poles is crucial for inducing significant furrowing. During furrowing, actomyosin flows align actin filaments parallel to the division plane, forming a contractile ring-like structure. Mechanical power is not greatest during contraction, but is maximized just before furrowing. This study reveals the quantitative relationship between force patterning and mechanical energy during division-like shape changes, providing insights into cell division mechanics.
Collapse
Affiliation(s)
- Ryota Sakamoto
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
| | - Michael P Murrell
- Department of Biomedical Engineering, Yale University, 10 Hillhouse Avenue, New Haven, CT, USA.
- Systems Biology Institute, 850 West Campus Drive, West Haven, CT, USA.
- Department of Physics, Yale University, 217 Prospect Street, New Haven, CT, USA.
| |
Collapse
|
3
|
Ecke M, Prassler J, Gerisch G. Expanding ring-shaped cleavage furrows in multinucleate cells. Mol Biol Cell 2023; 34:ar27. [PMID: 36652336 PMCID: PMC10092652 DOI: 10.1091/mbc.e22-10-0487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/20/2022] [Accepted: 01/09/2023] [Indexed: 01/19/2023] Open
Abstract
Multinucleate cells of Dictyostelium discoideum divide usually by unilateral cleavage furrows that ingress from the cell border. Along their path into the cell, they follow regions that are rich in myosin II and cortexillin and leave out the areas around the spindle poles that are populated with microtubule asters. In cells of a D. discoideum mutant that remain spread during mitosis we observed, as a rare event, cleavage by the expansion of a hole that is initiated in the middle of the cell area and has no connection with the cell's periphery. Here we show that these ring-shaped furrows develop in two phases, the first being reversible. During the first phase, the dorsal and ventral cell cortices come in close apposition and the cell membrane detaches locally from the substrate surface. The second phase comprises formation of the hole by membrane fusion and expansion of the opening toward the border of the cell, eventually cutting the multinucleate cell into pieces. We address the three-dimensional organization of ring-shaped furrows, their interaction with lateral furrows, and their association with filamentous myosin II and cortexillin. Thus, despite their geometrical divergence, similar molecular mechanisms might link the expanding hole to the standard contractile ring.
Collapse
Affiliation(s)
- Mary Ecke
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Jana Prassler
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Günther Gerisch
- Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| |
Collapse
|
4
|
Singh J, Imran Alsous J, Garikipati K, Shvartsman SY. Mechanics of stabilized intercellular bridges. Biophys J 2022; 121:3162-3171. [PMID: 35778841 PMCID: PMC9463629 DOI: 10.1016/j.bpj.2022.06.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/04/2022] [Accepted: 06/27/2022] [Indexed: 11/02/2022] Open
Abstract
Numerous engineered and natural systems form through reinforcement and stabilization of a deformed configuration that was generated by a transient force. An important class of such structures arises during gametogenesis, when a dividing cell undergoes incomplete cytokinesis, giving rise to daughter cells that remain connected through a stabilized intercellular bridge (ICB). ICBs can form through arrest of the contractile cytokinetic furrow and its subsequent stabilization. Despite knowledge of the molecular components, the mechanics underlying robust ICB assembly and the interplay between ring contractility and stiffening are poorly understood. Here, we report joint experimental and theoretical work that explores the physics underlying robust ICB assembly. We develop a continuum mechanics model that reveals the minimal requirements for the formation of stable ICBs, and validate the model's equilibrium predictions through a tabletop experimental analog. With insight into the equilibrium states, we turn to the dynamics: we demonstrate that contractility and stiffening are in dynamic competition and that the time intervals of their action must overlap to ensure assembly of ICBs of biologically observed proportions. Our results highlight a mechanism in which deformation and remodeling are tightly coordinated-one that is applicable to several mechanics-based applications and is a common theme in biological systems spanning several length scales.
Collapse
Affiliation(s)
- Jaspreet Singh
- Center for Computational Biology, Flatiron Institute, New York, New York
| | | | - Krishna Garikipati
- Departments of Mechanical Engineering, and Mathematics, Michigan Institute for Computational Discovery & Engineering, University of Michigan, Ann Arbor, Michigan.
| | - Stanislav Y Shvartsman
- Department of Molecular Biology, Princeton University, Princeton, New Jersey; The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey.
| |
Collapse
|
5
|
Gerisch G, Prassler J, Ecke M. Patterning of the cell cortex and the localization of cleavage furrows in multi-nucleate cells. J Cell Sci 2022; 135:275044. [PMID: 35274133 PMCID: PMC9016623 DOI: 10.1242/jcs.259648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/07/2022] [Indexed: 12/03/2022] Open
Abstract
In multi-nucleate cells of Dictyostelium, cytokinesis is performed by unilateral cleavage furrows that ingress the large cells from their border. We use a septase (sepA)-null mutant with delayed cytokinesis to show that in anaphase a pattern is generated in the cell cortex of cortexillin and myosin II. In multi-nucleate cells, these proteins decorate the entire cell cortex except circular zones around the centrosomes. Unilateral cleavage furrows are initiated at spaces free of microtubule asters and invade the cells along trails of cortexillin and myosin II accumulation. Where these areas widen, the cleavage furrow may branch or expand. When two furrows meet, they fuse, thus separating portions of the multi-nucleate cell from each other. Unilateral furrows are distinguished from the contractile ring of a normal furrow by their expansion rather than constriction. This is particularly evident for expanding ring-shaped furrows that are formed in the centre of a large multi-nucleate cell. Our data suggest that the myosin II-enriched area in multi-nucleate cells is a contractile sheet that pulls on the unilateral furrows and, in that way, expands them. Summary: Multi-nucleate Dictyostelium cells divide by unilateral cleavage furrows that progress and expand according to a pattern of cortexillin and myosin II that is determined by microtubule asters at the spindle poles.
Collapse
Affiliation(s)
- Günther Gerisch
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Jana Prassler
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Mary Ecke
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| |
Collapse
|
6
|
Koh SP, Pham NP, Piekny A. Seeing is believing: tools to study the role of Rho GTPases during cytokinesis. Small GTPases 2022; 13:211-224. [PMID: 34405757 PMCID: PMC9707540 DOI: 10.1080/21541248.2021.1957384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cytokinesis is required to cleave the daughter cells at the end of mitosis and relies on the spatiotemporal control of RhoA GTPase. Cytokinesis failure can lead to changes in cell fate or aneuploidy, which can be detrimental during development and/or can lead to cancer. However, our knowledge of the pathways that regulate RhoA during cytokinesis is limited, and the role of other Rho family GTPases is not clear. This is largely because the study of Rho GTPases presents unique challenges using traditional cell biological and biochemical methods, and they have pleiotropic functions making genetic studies difficult to interpret. The recent generation of optogenetic tools and biosensors that control and detect active Rho has overcome some of these challenges and is helping to elucidate the role of RhoA in cytokinesis. However, improvements are needed to reveal the role of other Rho GTPases in cytokinesis, and to identify the molecular mechanisms that control Rho activity. This review examines some of the outstanding questions in cytokinesis, and explores tools for the imaging and control of Rho GTPases.
Collapse
Affiliation(s)
- Su Pin Koh
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Nhat Phi Pham
- Department of Biology, Concordia University, Montreal, QC, Canada
| | - Alisa Piekny
- Department of Biology, Concordia University, Montreal, QC, Canada,CONTACT Alisa Piekny Department of Biology, Concordia University, 7141 Sherbrooke St. W, Montreal, QC, Canada
| |
Collapse
|
7
|
Le Goff T, Liebchen B, Marenduzzo D. Actomyosin Contraction Induces In-Bulk Motility of Cells and Droplets. Biophys J 2020; 119:1025-1032. [PMID: 32795395 DOI: 10.1016/j.bpj.2020.06.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/29/2020] [Accepted: 06/01/2020] [Indexed: 01/07/2023] Open
Abstract
Cell crawling on two-dimensional surfaces is a relatively well-understood phenomenon that is based on actin polymerization at a cell's front edge and anchoring on a substrate, allowing the cell to pull itself forward. However, some cells, such as cancer cells invading a three-dimensional matrigel, can also swim in the bulk, where surface adhesion is impossible. Although there is strong evidence that the self-organized engine that drives cells forward in the bulk involves myosin, the specific propulsion mechanism remains largely unclear. Here, we propose a minimal model for in-bulk self-motility of a droplet containing an isotropic and compressible contractile gel, representing a cell extract containing a disordered actomyosin network. In our model, contraction mediates a feedback loop between myosin-induced flow and advection-induced myosin accumulation, which leads to clustering and locally enhanced flow. The symmetry of such flow is then spontaneously broken through actomyosin-membrane interactions, leading to self-organized droplet motility relative to the underlying solvent. Depending on the balance between contraction, diffusion, detachment rate of myosin, and effective surface tension, this motion can be either straight or circular. Our simulations and analytical results shed new light on in-bulk myosin-driven cell motility in living cells and provide a framework to design a novel type of synthetic active matter droplet potentially resembling the motility mechanism of biological cells.
Collapse
Affiliation(s)
| | - Benno Liebchen
- Institute of Condensed Matter Physics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Davide Marenduzzo
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh, United Kingdom.
| |
Collapse
|
8
|
Bindl J, Molnar ES, Ecke M, Prassler J, Müller-Taubenberger A, Gerisch G. Unilateral Cleavage Furrows in Multinucleate Cells. Cells 2020; 9:E1493. [PMID: 32570994 PMCID: PMC7349700 DOI: 10.3390/cells9061493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 12/16/2022] Open
Abstract
Multinucleate cells can be produced in Dictyostelium by electric pulse-induced fusion. In these cells, unilateral cleavage furrows are formed at spaces between areas that are controlled by aster microtubules. A peculiarity of unilateral cleavage furrows is their propensity to join laterally with other furrows into rings to form constrictions. This means cytokinesis is biphasic in multinucleate cells, the final abscission of daughter cells being independent of the initial direction of furrow progression. Myosin-II and the actin filament cross-linking protein cortexillin accumulate in unilateral furrows, as they do in the normal cleavage furrows of mononucleate cells. In a myosin-II-null background, multinucleate or mononucleate cells were produced by cultivation either in suspension or on an adhesive substrate. Myosin-II is not essential for cytokinesis either in mononucleate or in multinucleate cells but stabilizes and confines the position of the cleavage furrows. In fused wild-type cells, unilateral furrows ingress with an average velocity of 1.7 µm × min-1, with no appreciable decrease of velocity in the course of ingression. In multinucleate myosin-II-null cells, some of the furrows stop growing, thus leaving space for the extensive broadening of the few remaining furrows.
Collapse
Affiliation(s)
- Julia Bindl
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Eszter Sarolta Molnar
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Mary Ecke
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Jana Prassler
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| | - Annette Müller-Taubenberger
- LMU Munich, Department of Cell Biology (Anatomy III), Biomedical Center, D-82152 Planegg-Martinsried, Germany;
| | - Günther Gerisch
- Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany; (J.B.); (E.S.M.); (M.E.); (J.P.)
| |
Collapse
|
9
|
Li X, Ni Q, He X, Kong J, Lim SM, Papoian GA, Trzeciakowski JP, Trache A, Jiang Y. Tensile force-induced cytoskeletal remodeling: Mechanics before chemistry. PLoS Comput Biol 2020; 16:e1007693. [PMID: 32520928 PMCID: PMC7326277 DOI: 10.1371/journal.pcbi.1007693] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/30/2020] [Accepted: 04/21/2020] [Indexed: 12/31/2022] Open
Abstract
Understanding cellular remodeling in response to mechanical stimuli is a critical step in elucidating mechanical activation of biochemical signaling pathways. Experimental evidence indicates that external stress-induced subcellular adaptation is accomplished through dynamic cytoskeletal reorganization. To study the interactions between subcellular structures involved in transducing mechanical signals, we combined experimental data and computational simulations to evaluate real-time mechanical adaptation of the actin cytoskeletal network. Actin cytoskeleton was imaged at the same time as an external tensile force was applied to live vascular smooth muscle cells using a fibronectin-functionalized atomic force microscope probe. Moreover, we performed computational simulations of active cytoskeletal networks under an external tensile force. The experimental data and simulation results suggest that mechanical structural adaptation occurs before chemical adaptation during filament bundle formation: actin filaments first align in the direction of the external force by initializing anisotropic filament orientations, then the chemical evolution of the network follows the anisotropic structures to further develop the bundle-like geometry. Our findings present an alternative two-step explanation for the formation of actin bundles due to mechanical stimulation and provide new insights into the mechanism of mechanotransduction. Remodeling the cytoskeletal network in response to external force is key to cellular mechanotransduction. Despite much focus on cytoskeletal remodeling in recent years, a comprehensive understanding of actin remodeling in real-time in cells under mechanical stimuli is still lacking. We integrated tensile stress-induced 3D actin remodeling and 3D computational simulations of actin cytoskeleton to study how the actin cytoskeleton form bundles and how these bundles evolve over time upon external tensile stress. We found that actin network remodels through a two-step process in which rapid alignment of actin filaments is followed by slower actin bundling. Based on these results, we propose a “mechanics before chemistry” model of actin cytoskeleton remodeling under external tensile force.
Collapse
Affiliation(s)
- Xiaona Li
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia, United States of America
| | - Qin Ni
- Department of Chemical & Biomolecular Engineering, University of Maryland, College Park, Maryland, United States of America
| | - Xiuxiu He
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia, United States of America
| | - Jun Kong
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia, United States of America
| | - Soon-Mi Lim
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Garegin A. Papoian
- Department of Chemistry & Biochemistry, University of Maryland, College Park, Maryland, United States of America
| | - Jerome P. Trzeciakowski
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
| | - Andreea Trache
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, United States of America
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Yi Jiang
- Department of Mathematics and Statistics, Georgia State University, Atlanta, Georgia, United States of America
- * E-mail:
| |
Collapse
|
10
|
Surcel A, Schiffhauer ES, Thomas DG, Zhu Q, DiNapoli KT, Herbig M, Otto O, West-Foyle H, Jacobi A, Kräter M, Plak K, Guck J, Jaffee EM, Iglesias PA, Anders RA, Robinson DN. Targeting Mechanoresponsive Proteins in Pancreatic Cancer: 4-Hydroxyacetophenone Blocks Dissemination and Invasion by Activating MYH14. Cancer Res 2019; 79:4665-4678. [PMID: 31358530 PMCID: PMC6744980 DOI: 10.1158/0008-5472.can-18-3131] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 06/11/2019] [Accepted: 07/22/2019] [Indexed: 12/16/2022]
Abstract
Metastasis is complex, involving multiple genetic, epigenetic, biochemical, and physical changes in the cancer cell and its microenvironment. Cells with metastatic potential are often characterized by altered cellular contractility and deformability, lending them the flexibility to disseminate and navigate through different microenvironments. We demonstrate that mechanoresponsiveness is a hallmark of pancreatic cancer cells. Key mechanoresponsive proteins, those that accumulate in response to mechanical stress, specifically nonmuscle myosin IIA (MYH9) and IIC (MYH14), α-actinin 4, and filamin B, were highly expressed in pancreatic cancer as compared with healthy ductal epithelia. Their less responsive sister paralogs-myosin IIB (MYH10), α-actinin 1, and filamin A-had lower expression differential or disappeared with cancer progression. We demonstrate that proteins whose cellular contributions are often overlooked because of their low abundance can have profound impact on cell architecture, behavior, and mechanics. Here, the low abundant protein MYH14 promoted metastatic behavior and could be exploited with 4-hydroxyacetophenone (4-HAP), which increased MYH14 assembly, stiffening cells. As a result, 4-HAP decreased dissemination, induced cortical actin belts in spheroids, and slowed retrograde actin flow. 4-HAP also reduced liver metastases in human pancreatic cancer-bearing nude mice. Thus, increasing MYH14 assembly overwhelms the ability of cells to polarize and invade, suggesting targeting the mechanoresponsive proteins of the actin cytoskeleton as a new strategy to improve the survival of patients with pancreatic cancer. SIGNIFICANCE: This study demonstrates that mechanoresponsive proteins become upregulated with pancreatic cancer progression and that this system of proteins can be pharmacologically targeted to inhibit the metastatic potential of pancreatic cancer cells.
Collapse
Affiliation(s)
- Alexandra Surcel
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - Eric S Schiffhauer
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Dustin G Thomas
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Qingfeng Zhu
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Kathleen T DiNapoli
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Electrical and Computer Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Maik Herbig
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Oliver Otto
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Hoku West-Foyle
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Angela Jacobi
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Martin Kräter
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Katarzyna Plak
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Jochen Guck
- Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, Dresden, Germany
| | - Elizabeth M Jaffee
- Department of Oncology, Sidney Kimmel Cancer Center at Johns Hopkins, The Skip Viragh Pancreatic Cancer Center, and the Bloomberg Kimmel Institute, Johns Hopkins University, Baltimore, Maryland
| | - Pablo A Iglesias
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Electrical and Computer Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, Maryland
| | - Robert A Anders
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| |
Collapse
|
11
|
Babkoff A, Cohen-Kfir E, Aharon H, Ronen D, Rosenberg M, Wiener R, Ravid S. A direct interaction between survivin and myosin II is required for cytokinesis. J Cell Sci 2019; 132:132/14/jcs233130. [PMID: 31315909 DOI: 10.1242/jcs.233130] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/14/2019] [Indexed: 02/05/2023] Open
Abstract
An acto-myosin contractile ring, which forms after anaphase onset and is highly regulated in time and space, mediates cytokinesis, the final step of mitosis. The chromosomal passenger complex (CPC), composed of Aurora-B kinase, INCENP, borealin and survivin (also known as BIRC5), regulates various processes during mitosis, including cytokinesis. It is not understood, however, how CPC regulates cytokinesis. We show that survivin binds to non-muscle myosin II (NMII), regulating its filament assembly. Survivin and NMII interact mainly in telophase, and Cdk1 regulates their interaction in a mitotic-phase-specific manner, revealing the mechanism for the specific timing of survivin-NMII interaction during mitosis. The survivin-NMII interaction is indispensable for cytokinesis, and its disruption leads to multiple mitotic defects. We further show that only the survivin homodimer binds to NMII, attesting to the biological importance for survivin homodimerization. We suggest a novel function for survivin in regulating the spatio-temporal formation of the acto-NMII contractile ring during cytokinesis and we elucidate the role of Cdk1 in regulating this process.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Aryeh Babkoff
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Einav Cohen-Kfir
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Hananel Aharon
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Daniel Ronen
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Michael Rosenberg
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Reuven Wiener
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Shoshana Ravid
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| |
Collapse
|
12
|
Abstract
Division of amoebas, fungi, and animal cells into two daughter cells at the end of the cell cycle depends on a common set of ancient proteins, principally actin filaments and myosin-II motors. Anillin, formins, IQGAPs, and many other proteins regulate the assembly of the actin filaments into a contractile ring positioned between the daughter nuclei by different mechanisms in fungi and animal cells. Interactions of myosin-II with actin filaments produce force to assemble and then constrict the contractile ring to form a cleavage furrow. Contractile rings disassemble as they constrict. In some cases, knowledge about the numbers of participating proteins and their biochemical mechanisms has made it possible to formulate molecularly explicit mathematical models that reproduce the observed physical events during cytokinesis by computer simulations.
Collapse
Affiliation(s)
- Thomas D Pollard
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA;
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8103, USA
- Department of Cell Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA;
| |
Collapse
|
13
|
Abstract
Division of amoebas, fungi, and animal cells into two daughter cells at the end of the cell cycle depends on a common set of ancient proteins, principally actin filaments and myosin-II motors. Anillin, formins, IQGAPs, and many other proteins regulate the assembly of the actin filaments into a contractile ring positioned between the daughter nuclei by different mechanisms in fungi and animal cells. Interactions of myosin-II with actin filaments produce force to assemble and then constrict the contractile ring to form a cleavage furrow. Contractile rings disassemble as they constrict. In some cases, knowledge about the numbers of participating proteins and their biochemical mechanisms has made it possible to formulate molecularly explicit mathematical models that reproduce the observed physical events during cytokinesis by computer simulations.
Collapse
Affiliation(s)
- Thomas D Pollard
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520-8103, USA;
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8103, USA
- Department of Cell Biology, Yale University, New Haven, Connecticut 06520-8103, USA
| | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA;
| |
Collapse
|
14
|
Schiffhauer ES, Ren Y, Iglesias VA, Kothari P, Iglesias PA, Robinson DN. Myosin IIB assembly state determines its mechanosensitive dynamics. J Cell Biol 2019; 218:895-908. [PMID: 30655296 PMCID: PMC6400566 DOI: 10.1083/jcb.201806058] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 11/20/2018] [Accepted: 12/19/2018] [Indexed: 11/22/2022] Open
Abstract
Dynamical cell shape changes require a highly sensitive cellular system that can respond to chemical and mechanical inputs. Myosin IIs are key players in the cell's ability to react to mechanical inputs, demonstrating an ability to accumulate in response to applied stress. Here, we show that inputs that influence the ability of myosin II to assemble into filaments impact the ability of myosin to respond to stress in a predictable manner. Using mathematical modeling for Dictyostelium myosin II, we predict that myosin II mechanoresponsiveness will be biphasic with an optimum established by the percentage of myosin II assembled into bipolar filaments. In HeLa and NIH 3T3 cells, heavy chain phosphorylation of NMIIB by PKCζ, as well as expression of NMIIA, can control the ability of NMIIB to mechanorespond by influencing its assembly state. These data demonstrate that multiple inputs to the myosin II assembly state integrate at the level of myosin II to govern the cellular response to mechanical inputs.
Collapse
Affiliation(s)
- Eric S Schiffhauer
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Yixin Ren
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Vicente A Iglesias
- Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD
| | - Priyanka Kothari
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Pablo A Iglesias
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD.,Department of Electrical and Computer Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD
| | - Douglas N Robinson
- Department of Cell Biology, School of Medicine, Johns Hopkins University, Baltimore, MD .,Department of Pharmacology and Molecular Sciences School of Medicine, Johns Hopkins University, Baltimore, MD.,Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD.,Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, MD
| |
Collapse
|
15
|
West-Foyle H, Kothari P, Osborne J, Robinson DN. 14-3-3 proteins tune non-muscle myosin II assembly. J Biol Chem 2018; 293:6751-6761. [PMID: 29549125 DOI: 10.1074/jbc.m117.819391] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/12/2018] [Indexed: 11/06/2022] Open
Abstract
The 14-3-3 family comprises a group of small proteins that are essential, ubiquitous, and highly conserved across eukaryotes. Overexpression of the 14-3-3 proteins σ, ϵ, ζ, and η correlates with high metastatic potential in multiple cancer types. In Dictyostelium, 14-3-3 promotes myosin II turnover in the cell cortex and modulates cortical tension, cell shape, and cytokinesis. In light of the important roles of 14-3-3 proteins across a broad range of eukaryotic species, we sought to determine how 14-3-3 proteins interact with myosin II. Here, conducting in vitro and in vivo studies of both Dictyostelium (one 14-3-3 and one myosin II) and human proteins (seven 14-3-3s and three nonmuscle myosin IIs), we investigated the mechanism by which 14-3-3 proteins regulate myosin II assembly. Using in vitro assembly assays with purified myosin II tail fragments and 14-3-3, we demonstrate that this interaction is direct and phosphorylation-independent. All seven human 14-3-3 proteins also altered assembly of at least one paralog of myosin II. Our findings indicate a mechanism of myosin II assembly regulation that is mechanistically conserved across a billion years of evolution from amebas to humans. We predict that altered 14-3-3 expression in humans inhibits the tumor suppressor myosin II, contributing to the changes in cell mechanics observed in many metastatic cancers.
Collapse
Affiliation(s)
| | | | | | - Douglas N Robinson
- From the Departments of Cell Biology, .,Pharmacology and Molecular Sciences, and.,Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| |
Collapse
|
16
|
Montembault E, Claverie MC, Bouit L, Landmann C, Jenkins J, Tsankova A, Cabernard C, Royou A. Myosin efflux promotes cell elongation to coordinate chromosome segregation with cell cleavage. Nat Commun 2017; 8:326. [PMID: 28835609 PMCID: PMC5569077 DOI: 10.1038/s41467-017-00337-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 06/21/2017] [Indexed: 12/02/2022] Open
Abstract
Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here we report that cells clear trailing chromatids from the cleavage site by undergoing two phases of cell elongation. The first phase relies on the assembly of a wide contractile ring. The second phase requires the activity of a pool of myosin that flows from the ring and enriches the nascent daughter cell cortices. This myosin efflux is a novel feature of cytokinesis and its duration is coupled to nuclear envelope reassembly and the nuclear sequestration of the Rho-GEF Pebble. Trailing chromatids induce a delay in nuclear envelope reassembly concomitant with prolonged cortical myosin activity, thus providing forces for the second elongation. We propose that the modulation of cortical myosin dynamics is part of the cellular response triggered by a “chromatid separation checkpoint” that delays nuclear envelope reassembly and, consequently, Pebble nuclear sequestration when trailing chromatids are present at the midzone. Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here the authors show that cells clear trailing chromatids from the cleavage site in a two-step cell elongation and demonstrate the role of myosin efflux in the second phase.
Collapse
Affiliation(s)
- Emilie Montembault
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France.
| | - Marie-Charlotte Claverie
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Lou Bouit
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Cedric Landmann
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - James Jenkins
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Anna Tsankova
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Clemens Cabernard
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Anne Royou
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France.
| |
Collapse
|
17
|
Reymann AC, Staniscia F, Erzberger A, Salbreux G, Grill SW. Cortical flow aligns actin filaments to form a furrow. eLife 2016; 5:e17807. [PMID: 27719759 PMCID: PMC5117871 DOI: 10.7554/elife.17807] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/07/2016] [Indexed: 01/27/2023] Open
Abstract
Cytokinesis in eukaryotic cells is often accompanied by actomyosin cortical flow. Over 30 years ago, Borisy and White proposed that cortical flow converging upon the cell equator compresses the actomyosin network to mechanically align actin filaments. However, actin filaments also align via search-and-capture, and to what extent compression by flow or active alignment drive furrow formation remains unclear. Here, we quantify the dynamical organization of actin filaments at the onset of ring assembly in the C. elegans zygote, and provide a framework for determining emergent actomyosin material parameters by the use of active nematic gel theory. We characterize flow-alignment coupling, and verify at a quantitative level that compression by flow drives ring formation. Finally, we find that active alignment enhances but is not required for ring formation. Our work characterizes the physical mechanisms of actomyosin ring formation and highlights the role of flow as a central organizer of actomyosin network architecture.
Collapse
Affiliation(s)
- Anne-Cecile Reymann
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Fabio Staniscia
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Anna Erzberger
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Guillaume Salbreux
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- The Francis Crick Institute, London, United Kingdom
| | - Stephan W Grill
- Biotechnology Center, Technische Universität Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| |
Collapse
|
18
|
A Combination of Actin Treadmilling and Cross-Linking Drives Contraction of Random Actomyosin Arrays. Biophys J 2016; 109:1818-29. [PMID: 26536259 DOI: 10.1016/j.bpj.2015.09.013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/14/2015] [Accepted: 09/18/2015] [Indexed: 01/02/2023] Open
Abstract
We investigate computationally the self-organization and contraction of an initially random actomyosin ring. In the framework of a detailed physical model for a ring of cross-linked actin filaments and myosin-II clusters, we derive the force balance equations and solve them numerically. We find that to contract, actin filaments have to treadmill and to be sufficiently cross linked, and myosin has to be processive. The simulations reveal how contraction scales with mechanochemical parameters. For example, they show that the ring made of longer filaments generates greater force but contracts slower. The model predicts that the ring contracts with a constant rate proportional to the initial ring radius if either myosin is released from the ring during contraction and actin filaments shorten, or if myosin is retained in the ring, while the actin filament number decreases. We demonstrate that a balance of actin nucleation and compression-dependent disassembly can also sustain contraction. Finally, the model demonstrates that with time pattern formation takes place in the ring, worsening the contractile process. The more random the actin dynamics are, the higher the contractility will be.
Collapse
|
19
|
Mohan K, Luo T, Robinson DN, Iglesias PA. Cell shape regulation through mechanosensory feedback control. J R Soc Interface 2016. [PMID: 26224568 DOI: 10.1098/rsif.2015.0512] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cells undergo controlled changes in morphology in response to intracellular and extracellular signals. These changes require a means for sensing and interpreting the signalling cues, for generating the forces that act on the cell's physical material, and a control system to regulate this process. Experiments on Dictyostelium amoebae have shown that force-generating proteins can localize in response to external mechanical perturbations. This mechanosensing, and the ensuing mechanical feedback, plays an important role in minimizing the effect of mechanical disturbances in the course of changes in cell shape, especially during cell division, and likely in other contexts, such as during three-dimensional migration. Owing to the complexity of the feedback system, which couples mechanical and biochemical signals involved in shape regulation, theoretical approaches can guide further investigation by providing insights that are difficult to decipher experimentally. Here, we present a computational model that explains the different mechanosensory and mechanoresponsive behaviours observed in Dictyostelium cells. The model features a multiscale description of myosin II bipolar thick filament assembly that includes cooperative and force-dependent myosin-actin binding, and identifies the feedback mechanisms hidden in the observed mechanoresponsive behaviours of Dictyostelium cells during micropipette aspiration experiments. These feedbacks provide a mechanistic explanation of cellular retraction and hence cell shape regulation.
Collapse
Affiliation(s)
- Krithika Mohan
- Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Tianzhi Luo
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Douglas N Robinson
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Pablo A Iglesias
- Department of Electrical and Computer Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| |
Collapse
|
20
|
Jung YW, Mascagni M. Constriction model of actomyosin ring for cytokinesis by fission yeast using a two-state sliding filament mechanism. J Chem Phys 2015; 141:125101. [PMID: 25273478 DOI: 10.1063/1.4896164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We developed a model describing the structure and contractile mechanism of the actomyosin ring in fission yeast, Schizosaccharomyces pombe. The proposed ring includes actin, myosin, and α-actinin, and is organized into a structure similar to that of muscle sarcomeres. This structure justifies the use of the sliding-filament mechanism developed by Huxley and Hill, but it is probably less organized relative to that of muscle sarcomeres. Ring contraction tension was generated via the same fundamental mechanism used to generate muscle tension, but some physicochemical parameters were adjusted to be consistent with the proposed ring structure. Simulations allowed an estimate of ring constriction tension that reproduced the observed ring constriction velocity using a physiologically possible, self-consistent set of parameters. Proposed molecular-level properties responsible for the thousand-fold slower constriction velocity of the ring relative to that of muscle sarcomeres include fewer myosin molecules involved, a less organized contractile configuration, a low α-actinin concentration, and a high resistance membrane tension. Ring constriction velocity is demonstrated as an exponential function of time despite a near linear appearance. We proposed a hypothesis to explain why excess myosin heads inhibit constriction velocity rather than enhance it. The model revealed how myosin concentration and elastic resistance tension are balanced during cytokinesis in S. pombe.
Collapse
Affiliation(s)
- Yong-Woon Jung
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA
| | - Michael Mascagni
- Departments of Computer Science, Mathematics and Scientific Computing, and Graduate Program in Molecular Biophysics, Florida State University, Tallahassee, Florida 32306-4530, USA
| |
Collapse
|
21
|
Sain A, Inamdar MM, Jülicher F. Dynamic force balances and cell shape changes during cytokinesis. PHYSICAL REVIEW LETTERS 2015; 114:048102. [PMID: 25679910 DOI: 10.1103/physrevlett.114.048102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Indexed: 06/04/2023]
Abstract
During the division of animal cells, an actomyosin ring is formed in the cell cortex. The contraction of this ring induces shape changes of the cell and the formation of a cytokinesis furrow. In many cases, a cell-cell interface forms that separates the two new cells. Here we present a simple physical description of the cell shape changes and the dynamics of the interface closure, based on force balances involving active stresses and viscous friction. We discuss conditions in which the interface closure is either axially symmetric or asymmetric. We show that our model can account for the observed dynamics of ring contraction and interface closure in the C. elegans embryo.
Collapse
Affiliation(s)
- Anirban Sain
- Physics Department, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India
| | - Mandar M Inamdar
- Department of Civil Engineering, Indian Institute of Technology-Bombay, Powai, Mumbai 400076, India
| | - Frank Jülicher
- Max-Planck-Institute for the Physics of Complex Systems Nöthnitzer Strasse 38, 01187 Dresden, Germany
| |
Collapse
|
22
|
Pharmacological activation of myosin II paralogs to correct cell mechanics defects. Proc Natl Acad Sci U S A 2015; 112:1428-33. [PMID: 25605895 DOI: 10.1073/pnas.1412592112] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Current approaches to cancer treatment focus on targeting signal transduction pathways. Here, we develop an alternative system for targeting cell mechanics for the discovery of novel therapeutics. We designed a live-cell, high-throughput chemical screen to identify mechanical modulators. We characterized 4-hydroxyacetophenone (4-HAP), which enhances the cortical localization of the mechanoenzyme myosin II, independent of myosin heavy-chain phosphorylation, thus increasing cellular cortical tension. To shift cell mechanics, 4-HAP requires myosin II, including its full power stroke, specifically activating human myosin IIB (MYH10) and human myosin IIC (MYH14), but not human myosin IIA (MYH9). We further demonstrated that invasive pancreatic cancer cells are more deformable than normal pancreatic ductal epithelial cells, a mechanical profile that was partially corrected with 4-HAP, which also decreased the invasion and migration of these cancer cells. Overall, 4-HAP modifies nonmuscle myosin II-based cell mechanics across phylogeny and disease states and provides proof of concept that cell mechanics offer a rich drug target space, allowing for possible corrective modulation of tumor cell behavior.
Collapse
|
23
|
Pollard TD. The value of mechanistic biophysical information for systems-level understanding of complex biological processes such as cytokinesis. Biophys J 2014; 107:2499-507. [PMID: 25468329 PMCID: PMC4255220 DOI: 10.1016/j.bpj.2014.10.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/06/2014] [Accepted: 10/08/2014] [Indexed: 12/15/2022] Open
Abstract
This review illustrates the value of quantitative information including concentrations, kinetic constants and equilibrium constants in modeling and simulating complex biological processes. Although much has been learned about some biological systems without these parameter values, they greatly strengthen mechanistic accounts of dynamical systems. The analysis of muscle contraction is a classic example of the value of combining an inventory of the molecules, atomic structures of the molecules, kinetic constants for the reactions, reconstitutions with purified proteins and theoretical modeling to account for the contraction of whole muscles. A similar strategy is now being used to understand the mechanism of cytokinesis using fission yeast as a favorable model system.
Collapse
Affiliation(s)
- Thomas D Pollard
- Departments of Molecular Cellular and Developmental Biology, Molecular Biophysics and Biochemistry, and Cell Biology, Yale University, New Haven, Connecticut.
| |
Collapse
|
24
|
Smith TC, Fridy PC, Li Y, Basil S, Arjun S, Friesen RM, Leszyk J, Chait BT, Rout MP, Luna EJ. Supervillin binding to myosin II and synergism with anillin are required for cytokinesis. Mol Biol Cell 2013; 24:3603-19. [PMID: 24088567 PMCID: PMC3842989 DOI: 10.1091/mbc.e12-10-0714] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cytokinesis, the process by which cytoplasm is apportioned between dividing daughter cells, requires coordination of myosin II function, membrane trafficking, and central spindle organization. Most known regulators act during late cytokinesis; a few, including the myosin II-binding proteins anillin and supervillin, act earlier. Anillin's role in scaffolding the membrane cortex with the central spindle is well established, but the mechanism of supervillin action is relatively uncharacterized. We show here that two regions within supervillin affect cell division: residues 831-1281, which bind central spindle proteins, and residues 1-170, which bind the myosin II heavy chain (MHC) and the long form of myosin light-chain kinase. MHC binding is required to rescue supervillin deficiency, and mutagenesis of this site creates a dominant-negative phenotype. Supervillin concentrates activated and total myosin II at the furrow, and simultaneous knockdown of supervillin and anillin additively increases cell division failure. Knockdown of either protein causes mislocalization of the other, and endogenous anillin increases upon supervillin knockdown. Proteomic identification of interaction partners recovered using a high-affinity green fluorescent protein nanobody suggests that supervillin and anillin regulate the myosin II and actin cortical cytoskeletons through separate pathways. We conclude that supervillin and anillin play complementary roles during vertebrate cytokinesis.
Collapse
Affiliation(s)
- Tara C Smith
- Program in Cell and Developmental Dynamics, Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655 Laboratory of Cellular and Structural Biology, Rockefeller University, New York, NY 10065 Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, NY 10065 Proteomics and Mass Spectrometry Facility, University of Massachusetts Medical School, Shrewsbury, MA 01545
| | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Fernandez-Gonzalez R, Zallen JA. Wounded cells drive rapid epidermal repair in the early Drosophila embryo. Mol Biol Cell 2013; 24:3227-37. [PMID: 23985320 PMCID: PMC3806660 DOI: 10.1091/mbc.e13-05-0228] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Epithelial tissues are protective barriers that display a remarkable ability to repair wounds. Wound repair is often associated with an accumulation of actin and nonmuscle myosin II around the wound, forming a purse string. The role of actomyosin networks in generating mechanical force during wound repair is not well understood. Here we investigate the mechanisms of force generation during wound repair in the epidermis of early and late Drosophila embryos. We find that wound closure is faster in early embryos, where, in addition to a purse string around the wound, actomyosin networks at the medial cortex of the wounded cells contribute to rapid wound repair. Laser ablation demonstrates that both medial and purse-string actomyosin networks generate contractile force. Quantitative analysis of protein localization dynamics during wound closure indicates that the rapid contraction of medial actomyosin structures during wound repair in early embryos involves disassembly of the actomyosin network. By contrast, actomyosin purse strings in late embryos contract more slowly in a mechanism that involves network condensation. We propose that the combined action of two force-generating structures--a medial actomyosin network and an actomyosin purse string--contributes to the increased efficiency of wound repair in the early embryo.
Collapse
Affiliation(s)
- Rodrigo Fernandez-Gonzalez
- Institute of Biomaterials and Biomedical Engineering and Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G9, Canada Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada Howard Hughes Medical Institute, Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065
| | | |
Collapse
|
26
|
Jiang H, Sun S. Cellular pressure and volume regulation and implications for cell mechanics. Biophys J 2013; 105:609-19. [PMID: 23931309 PMCID: PMC3736675 DOI: 10.1016/j.bpj.2013.06.021] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/04/2013] [Accepted: 06/12/2013] [Indexed: 11/20/2022] Open
Abstract
In eukaryotic cells, small changes in cell volume can serve as important signals for cell proliferation, death, and migration. Volume and shape regulation also directly impacts the mechanics of cells and tissues. Here, we develop a mathematical model of cellular volume and pressure regulation, incorporating essential elements such as water permeation, mechanosensitive channels, active ion pumps, and active stresses in the cortex. The model can fully explain recent experimental data, and it predicts cellular volume and pressure for several models of cell cortical mechanics. Moreover, we show that when cells are subjected to an externally applied load, such as in an atomic force microscopy indentation experiment, active regulation of volume and pressure leads to a complex cellular response. Instead of the passive mechanics of the cortex, the observed cell stiffness depends on several factors working together. This provides a mathematical explanation of rate-dependent response of cells under force.
Collapse
Affiliation(s)
- Hongyuan Jiang
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Sean X. Sun
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland
- Department of Biomedical Engineering and Johns Hopkins Physical Oncology Center, Johns Hopkins University, Baltimore, Maryland
| |
Collapse
|
27
|
Salbreux G, Charras G, Paluch E. Actin cortex mechanics and cellular morphogenesis. Trends Cell Biol 2012; 22:536-45. [PMID: 22871642 DOI: 10.1016/j.tcb.2012.07.001] [Citation(s) in RCA: 531] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 06/27/2012] [Accepted: 07/04/2012] [Indexed: 12/11/2022]
Abstract
The cortex is a thin, crosslinked actin network lying immediately beneath the plasma membrane of animal cells. Myosin motors exert contractile forces in the meshwork. Because the cortex is attached to the cell membrane, it plays a central role in cell shape control. The proteic constituents of the cortex undergo rapid turnover, making the cortex both mechanically rigid and highly plastic, two properties essential to its function. The cortex has recently attracted increasing attention and its functions in cellular processes such as cytokinesis, cell migration, and embryogenesis are progressively being dissected. In this review, we summarize current knowledge on the structural organization, composition, and mechanics of the actin cortex, focusing on the link between molecular processes and macroscopic physical properties. We also highlight consequences of cortex dysfunction in disease.
Collapse
Affiliation(s)
- Guillaume Salbreux
- Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany.
| | | | | |
Collapse
|
28
|
Abstract
Cytokinesis, the final step in cell division, partitions the contents of a single cell into two. In animal cells, cytokinesis occurs through cortical remodeling orchestrated by the anaphase spindle. Cytokinesis relies on a tight interplay between signaling and cellular mechanics and has attracted the attention of both biologists and physicists for more than a century. In this review, we provide an overview of four topics in animal cell cytokinesis: (a) signaling between the anaphase spindle and cortex, (b) the mechanics of cortical remodeling, (c) abscission, and (d) regulation of cytokinesis by the cell cycle machinery. We report on recent progress in these areas and highlight some of the outstanding questions that these findings bring into focus.
Collapse
Affiliation(s)
- Rebecca A Green
- Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, California 92093, USA.
| | | | | |
Collapse
|
29
|
West-Foyle H, Robinson DN. Cytokinesis mechanics and mechanosensing. Cytoskeleton (Hoboken) 2012; 69:700-9. [PMID: 22761196 DOI: 10.1002/cm.21045] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/11/2012] [Indexed: 01/13/2023]
Abstract
Cytokinesis shape change occurs through the interfacing of three modules, cell mechanics, myosin II-mediated contractile stress generation and sensing, and a control system of regulatory proteins, which together ensure flexibility and robustness. This integrated system then defines the stereotypical shape changes of successful cytokinesis, which occurs under a diversity of mechanical contexts and environmental conditions.
Collapse
Affiliation(s)
- Hoku West-Foyle
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | |
Collapse
|
30
|
Poirier CC, Ng WP, Robinson DN, Iglesias PA. Deconvolution of the cellular force-generating subsystems that govern cytokinesis furrow ingression. PLoS Comput Biol 2012; 8:e1002467. [PMID: 22570593 PMCID: PMC3343096 DOI: 10.1371/journal.pcbi.1002467] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 02/24/2012] [Indexed: 01/14/2023] Open
Abstract
Cytokinesis occurs through the coordinated action of several biochemically-mediated stresses acting on the cytoskeleton. Here, we develop a computational model of cellular mechanics, and using a large number of experimentally measured biophysical parameters, we simulate cell division under a number of different scenarios. We demonstrate that traction-mediated protrusive forces or contractile forces due to myosin II are sufficient to initiate furrow ingression. Furthermore, we show that passive forces due to the cell's cortical tension and surface curvature allow the furrow to complete ingression. We compare quantitatively the furrow thinning trajectories obtained from simulation with those observed experimentally in both wild-type and myosin II null Dictyostelium cells. Our simulations highlight the relative contributions of different biomechanical subsystems to cell shape progression during cell division. Cytokinesis, the physical separation of a mother cell into two daughter cells, requires force to deform the cell. Though there is ample evidence in many systems that myosin II provides some of this force, it is also well known that some cell types can divide in the absence of myosin II. To elucidate the mechanisms by which cells control furrow ingression, we developed a computational model of cellular dynamics during cytokinesis in the social amoeba, Dictyostelium discoideum. We took advantage of a large number of experimentally measured parameters and well-characterized furrow ingression dynamics for a number of different strains. Our simulations demonstrate that there are distinct phases of cytokinesis. Myosin II plays a role providing the stress that initiates furrow ingression. In its absence, however, this force can be supplied by a combination of adhesion and protrusion-mediated stresses. Thereafter, Laplace-like pressures take over and provide stresses that enable the cell to divide. Overall, we show how various mechanical parameters quantitatively impact furrow ingression kinetics, accounting for the cytokinesis dynamics of wild type and mutant cell-lines.
Collapse
Affiliation(s)
- Christopher C Poirier
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland, United States of America
| | | | | | | |
Collapse
|
31
|
Separation anxiety: stress, tension and cytokinesis. Exp Cell Res 2012; 318:1428-34. [PMID: 22487096 DOI: 10.1016/j.yexcr.2012.03.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Revised: 03/23/2012] [Accepted: 03/24/2012] [Indexed: 01/07/2023]
Abstract
Cytokinesis, the physical separation of a mother cell into two daughter cells, progresses through a series of well-defined changes in morphology. These changes involve distinct biochemical and mechanical processes. Here, we review the mechanical features of cells during cytokinesis, discussing both the material properties as well as sources of stresses, both active and passive, which lead to the observed changes in morphology. We also describe a mechanosensory feedback control system that regulates protein localization and shape progression during cytokinesis.
Collapse
|
32
|
Calvert MEK, Wright GD, Leong FY, Chiam KH, Chen Y, Jedd G, Balasubramanian MK. Myosin concentration underlies cell size-dependent scalability of actomyosin ring constriction. ACTA ACUST UNITED AC 2012; 195:799-813. [PMID: 22123864 PMCID: PMC3257563 DOI: 10.1083/jcb.201101055] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The rate of actomyosin ring constriction in cells of different sizes correlates with myosin motor concentration in Neurospora crassa cells, leading to increased division rates in larger cells during cytokinesis. In eukaryotes, cytokinesis is accomplished by an actomyosin-based contractile ring. Although in Caenorhabditis elegans embryos larger cells divide at a faster rate than smaller cells, it remains unknown whether a similar mode of scalability operates in other cells. We investigated cytokinesis in the filamentous fungus Neurospora crassa, which exhibits a wide range of hyphal circumferences. We found that N. crassa cells divide using an actomyosin ring and larger rings constricted faster than smaller rings. However, unlike in C. elegans, the total amount of myosin remained constant throughout constriction, and there was a size-dependent increase in the starting concentration of myosin in the ring. We predict that the increased number of ring-associated myosin motors in larger rings leads to the increased constriction rate. Accordingly, reduction or inhibition of ring-associated myosin slows down the rate of constriction. Because the mechanical characteristics of contractile rings are conserved, we predict that these findings will be relevant to actomyosin ring constriction in other cell types.
Collapse
Affiliation(s)
- Meredith E K Calvert
- Temasek Life Sciences Laboratory, The National University of Singapore, Singapore 117604.
| | | | | | | | | | | | | |
Collapse
|
33
|
Ca2+-Mediated Synthetic Biosystems Offer Protein Design Versatility, Signal Specificity, and Pathway Rewiring. ACTA ACUST UNITED AC 2011; 18:1611-9. [DOI: 10.1016/j.chembiol.2011.09.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 09/06/2011] [Accepted: 09/19/2011] [Indexed: 12/30/2022]
|
34
|
Abstract
The mechanisms by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored using a simplified model of the cytoskeleton as a viscous gel containing active stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of active stress and cell-substrate friction. It is found that 1) the cell velocity is given by a function that quantifies the asymmetry of the active-stress distribution, 2) gradients in cell-substrate friction can induce motion even when the active stresses are symmetrically distributed, 3) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell, and 4) the cell velocity depends biphasically on the cell-substrate adhesion strength if active stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed.
Collapse
Affiliation(s)
- A E Carlsson
- Department of Physics, Washington University, Campus Box 1105, One Brookings Drive, St. Louis, MO. 63130, U.S.A
| |
Collapse
|
35
|
Zhou Q, Kee YS, Poirier CC, Jelinek C, Osborne J, Divi S, Surcel A, Will ME, Eggert US, Müller-Taubenberger A, Iglesias PA, Cotter RJ, Robinson DN. 14-3-3 coordinates microtubules, Rac, and myosin II to control cell mechanics and cytokinesis. Curr Biol 2010; 20:1881-9. [PMID: 20951045 DOI: 10.1016/j.cub.2010.09.048] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 08/12/2010] [Accepted: 09/15/2010] [Indexed: 12/20/2022]
Abstract
BACKGROUND During cytokinesis, regulatory signals are presumed to emanate from the mitotic spindle. However, what these signals are and how they lead to the spatiotemporal changes in the cortex structure, mechanics, and regional contractility are not well understood in any system. RESULTS To investigate pathways that link the microtubule network to the cortical changes that promote cytokinesis, we used chemical genetics in Dictyostelium to identify genetic suppressors of nocodazole, a microtubule depolymerizer. We identified 14-3-3 and found that it is enriched in the cortex, helps maintain steady-state microtubule length, contributes to normal cortical tension, modulates actin wave formation, and controls the symmetry and kinetics of cleavage furrow contractility during cytokinesis. Furthermore, 14-3-3 acts downstream of a Rac small GTPase (RacE), associates with myosin II heavy chain, and is needed to promote myosin II bipolar thick filament remodeling. CONCLUSIONS 14-3-3 connects microtubules, Rac, and myosin II to control several aspects of cortical dynamics, mechanics, and cytokinesis cell shape change. Furthermore, 14-3-3 interacts directly with myosin II heavy chain to promote bipolar thick filament remodeling and distribution. Overall, 14-3-3 appears to integrate several critical cytoskeletal elements that drive two important processes-cytokinesis cell shape change and cell mechanics.
Collapse
Affiliation(s)
- Qiongqiong Zhou
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Surcel A, Kee YS, Luo T, Robinson DN. Cytokinesis through biochemical-mechanical feedback loops. Semin Cell Dev Biol 2010; 21:866-73. [PMID: 20709619 DOI: 10.1016/j.semcdb.2010.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 06/22/2010] [Accepted: 08/03/2010] [Indexed: 10/19/2022]
Abstract
Cytokinesis is emerging as a control system defined by interacting biochemical and mechanical modules, which form a system of feedback loops. This integrated system accounts for the regulation and kinetics of cytokinesis furrowing and demonstrates that cytokinesis is a whole-cell process in which the global and equatorial cortices and cytoplasm are active players in the system. Though originally defined in Dictyostelium, features of the control system are recognizable in other organisms, suggesting a universal mechanism for cytokinesis regulation and contractility.
Collapse
Affiliation(s)
- Alexandra Surcel
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | |
Collapse
|
37
|
Pollard TD. Mechanics of cytokinesis in eukaryotes. Curr Opin Cell Biol 2010; 22:50-6. [PMID: 20031383 PMCID: PMC2871152 DOI: 10.1016/j.ceb.2009.11.010] [Citation(s) in RCA: 227] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Revised: 11/19/2009] [Accepted: 11/20/2009] [Indexed: 12/11/2022]
Abstract
Research on eukaryotic cytokinesis using advantageous model systems is rapidly advancing our understanding of most aspects of the process. Cytokinesis is very complicated with more than 100 proteins participating. Both fungi and animal cells use proteins to mark the cleavage site for the assembly of a contractile ring of actin filaments and myosin-II. Formins nucleate and elongate the actin filaments and myosin-II helps to organize the filaments into a contractile ring. Much is still to be learned about the organization of the contractile ring and the mechanisms that disassemble the ring as it constricts. Although fungi and animals share many proteins that contribute to cytokinesis, the extent to which they share mechanisms for the location, assembly, constriction, and disassembly of their contractile rings is still in question.
Collapse
Affiliation(s)
- Thomas D Pollard
- Department of Molecular Cellular, Yale University, PO Box 208103, New Haven, CT 06520-8103, USA.
| |
Collapse
|
38
|
Ren Y, Effler JC, Norstrom M, Luo T, Firtel RA, Iglesias PA, Rock RS, Robinson DN. Mechanosensing through cooperative interactions between myosin II and the actin crosslinker cortexillin I. Curr Biol 2009; 19:1421-8. [PMID: 19646871 DOI: 10.1016/j.cub.2009.07.018] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 07/02/2009] [Accepted: 07/03/2009] [Indexed: 11/15/2022]
Abstract
BACKGROUND Mechanosensing governs many processes from molecular to organismal levels, including during cytokinesis where it ensures successful and symmetrical cell division. Although many proteins are now known to be force sensitive, myosin motors with their ATPase activity and force-sensitive mechanical steps are well poised to facilitate cellular mechanosensing. For a myosin motor to experience tension, the actin filament must also be anchored. RESULTS Here, we find a cooperative relationship between myosin II and the actin crosslinker cortexillin I where both proteins are essential for cellular mechanosensory responses. Although many functions of cortexillin I and myosin II are dispensable for cytokinesis, all are required for full mechanosensing. Our analysis demonstrates that this mechanosensor has three critical elements: the myosin motor where the lever arm acts as a force amplifier, a force-sensitive bipolar thick-filament assembly, and a long-lived actin crosslinker, which anchors the actin filament so that the motor may experience tension. We also demonstrate that a Rac small GTPase inhibits this mechanosensory module during interphase, allowing the module to be primarily active during cytokinesis. CONCLUSIONS Overall, myosin II and cortexillin I define a cellular-scale mechanosensor that controls cell shape during cytokinesis. This system is exquisitely tuned through the enzymatic properties of the myosin motor, its lever arm length, and bipolar thick-filament assembly dynamics. The system also requires cortexillin I to stably anchor the actin filament so that the myosin motor can experience tension. Through this cross-talk, myosin II and cortexillin I define a cellular-scale mechanosensor that monitors and corrects shape defects, ensuring symmetrical cell division.
Collapse
Affiliation(s)
- Yixin Ren
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Ghosh B, Sain A. Origin of contractile force during cell division of bacteria. PHYSICAL REVIEW LETTERS 2008; 101:178101. [PMID: 18999788 DOI: 10.1103/physrevlett.101.178101] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Indexed: 05/27/2023]
Abstract
When a bacterium divides, its cell wall at the division site grows radially inward like the shutter of a camera and guillotines the cell into two halves. The wall is pulled upon from inside by a polymeric ring, which itself shrinks in radius. The ring is made of an intracellular protein FtsZ (filamenting temperature sensitive Z) and thus is called the Z ring. It is not understood how the Z ring generates the required contractile force. We propose a theoretical model and simulate it to show how the natural curvature of the FtsZ filaments and lateral attraction among them may facilitate force generation.
Collapse
Affiliation(s)
- Biplab Ghosh
- Physics Department, Indian Institute of Technology-Bombay, Powai, Mumbai, India
| | | |
Collapse
|
40
|
Yang L, Effler JC, Kutscher BL, Sullivan SE, Robinson DN, Iglesias PA. Modeling cellular deformations using the level set formalism. BMC SYSTEMS BIOLOGY 2008; 2:68. [PMID: 18652669 PMCID: PMC2535594 DOI: 10.1186/1752-0509-2-68] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 07/24/2008] [Indexed: 01/09/2023]
Abstract
Background Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM), in which the cellular shape is defined implicitly, thereby eschewing the need for updating boundaries. Results We obtain a viscoelastic model of Dictyostelium cells using micropipette aspiration and show how this viscoelastic model can be incorporated into LSM simulations to recreate the observed protrusion of cells into the micropipette faithfully. We also demonstrate the use of our techniques by simulating the cell shape changes elicited by the chemotactic response to an external chemoattractant gradient. Conclusion Our results provide a simple but effective means of incorporating cellular deformations into mathematical simulations of cell signaling. Such methods will be useful for simulating important cellular events such as chemotaxis and cytokinesis.
Collapse
Affiliation(s)
- Liu Yang
- Electrical & Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
| | | | | | | | | | | |
Collapse
|
41
|
Bauer T, Motosugi N, Miura K, Sabe H, Hiiragi T. Dynamic rearrangement of surface proteins is essential for cytokinesis. Genesis 2008; 46:152-62. [PMID: 18327789 DOI: 10.1002/dvg.20377] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cytokinesis is a complex process that involves dynamic cortical rearrangement. Our recent time-lapse recordings of the mouse egg unexpectedly revealed a high motility of the second polar body (2pb). Experiments to address its underlying mechanism show that neither mechanical compression by the zona pellucida nor the connection via the mid-body is required for the 2pb movement. Time-lapse recordings establish that the 2pb moves together with the cell membrane. These recordings, in which cell surface proteins are labeled with fluorescent latex-microbeads or monovalent antibodies against whole mouse proteins, indicate that the majority of the surface proteins dynamically accumulate in the cleavage furrow at every cell division. Comparable dynamics of the cell surface proteins, and specifically of E-cadherin, are also observed in cultured epithelial cells. The surface protein dynamics are closely correlated with, and dependent on, those of the underlying cortical actin. The cortical actin network may form a scaffold for membrane proteins and thereby transfer them during contractile ring formation toward the cleavage furrow. Immobilization of surface proteins by tetravalent lectin-mediated crosslinking results in the failure of cleavage, demonstrating that the observed protein dynamics are essential for cytokinesis. We propose that dynamic rearrangement of the cell surface proteins is a common feature of cytokinesis, playing a key role in modifying the mechanical properties of the cell membrane during cortical ingression.
Collapse
Affiliation(s)
- Tobias Bauer
- Department of Developmental Biology, Max-Planck Institute of Immunobiology, Freiburg D-79108, Germany
| | | | | | | | | |
Collapse
|
42
|
Wu JQ, McCormick CD, Pollard TD. Chapter 9 Counting Proteins in Living Cells by Quantitative Fluorescence Microscopy with Internal Standards. Methods Cell Biol 2008; 89:253-73. [DOI: 10.1016/s0091-679x(08)00609-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
|
43
|
Abstract
Blebs are spherical cellular protrusions that occur in many physiological situations. Two distinct phases make up the life of a bleb, each of which have their own biology and physics: expansion, which lasts approximately 30 s, and retraction, which lasts approximately 2 min. We investigate these phases using optical microscopy and simple theoretical concepts, seeking information on blebbing itself, and on cytomechanics in general. We show that bleb nucleation depends on pressure, membrane-cortex adhesion energy, and membrane tension, and test this experimentally. Bleb growth occurs through a combination of bulk flow of lipids and delamination from the cell cortex via the formation and propagation of tears. In extreme cases, this can give rise to a traveling wave around the cell periphery, known as "circus movement." When growth stalls, an actin cortex reforms under the bleb membrane, and retraction starts, driven by myosin-II. Using flicker spectroscopy, we find that retracting blebs are fivefold more rigid than expanding blebs, an increase entirely explained by the properties of the newly formed cortical actin mesh. Finally, using artificially nucleated blebs as pressure sensors, we show that cells rounded up in mitosis possess a substantial intracellular pressure.
Collapse
|
44
|
Effler JC, Iglesias PA, Robinson DN. A mechanosensory system controls cell shape changes during mitosis. Cell Cycle 2007; 6:30-5. [PMID: 17245114 PMCID: PMC4638380 DOI: 10.4161/cc.6.1.3674] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Essential life processes are heavily controlled by a variety of positive and negative feedback systems. Cytokinesis failure, ultimately leading to aneuploidy, is appreciated as an early step in tumor formation in mammals and is deleterious for all cells. Further, the growing list of cancer predisposition mutations includes a number of genes whose proteins control mitosis and/or cytokinesis. Cytokinesis shape control is also an important part of pattern formation and cell-type specialization during multi-cellular development. Inherently mechanical, we hypothesized that mechanosensing and mechanical feedback are fundamental for cytokinesis shape regulation. Using mechanical perturbation, we identified a mechanosensory control system that monitors shape progression during cytokinesis. In this review, we summarize these findings and their implications for cytokinesis regulation and for understanding the cytoskeletal system architecture that governs shape control.
Collapse
Affiliation(s)
- Janet C. Effler
- Department of Cell Biology, Johns Hopkins University School of Medicine; Baltimore, Maryland USA
- Department of Electrical and Computer Engineering; Johns Hopkins University; Whiting School of Engineering; Baltimore, Maryland USA
| | - Pablo A. Iglesias
- Department of Electrical and Computer Engineering; Johns Hopkins University; Whiting School of Engineering; Baltimore, Maryland USA
| | - Douglas N. Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine; Baltimore, Maryland USA
| |
Collapse
|
45
|
Hamaguchi Y, Numata T, K Satoh S. Quantitative Analysis of Cortical Actin Filaments during Polar Body Formation in Starfish Oocytes. Cell Struct Funct 2007; 32:29-40. [PMID: 17575411 DOI: 10.1247/csf.06034] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Polar body formation is an extremely unequal cell division. In order to understand the mechanism of polar body formation, morphological changes at the animal pole were investigated in living oocytes of the starfish, Asterina pectinifera, and the amounts of cortical actin filaments were quantitatively estimated after staining the maturing oocytes with fluorescently-labeled phallotoxins using a computer and image-processing software. Formation of a bulge, which is presumed to become a polar body, and the anaphase separation of chromosomes occurred simultaneously. When the bulge became large, one group of chromatids moved into the bulge. The dividing furrow then formed and finally a polar body formed. Just at the time of bulge formation, the intensity of the fluorescence produced by the actin filaments at the top of the animal pole began to decrease, and subsequently the intensity at the top fell to half of the original value. On the other hand, the fluorescence intensity at the base of the bulge increased gradually. This actin accumulation at the base created a dividing furrow around the top of the animal pole as the bulge grew. Even when the polar body formation was inhibited mechanically, a similar pattern of actin deficiency and accumulation in the cortex near the animal pole was observed. This indicates that such regulation of filamentous actin can take place without bulging. Therefore, polar body formation is initiated by the bulging of the cortex weakened by actin deficiency and followed by contraction of the base of the bulge reinforced by actin accumulation.
Collapse
Affiliation(s)
- Yukihisa Hamaguchi
- Department of Bioengineering, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan.
| | | | | |
Collapse
|
46
|
Eppinga RD, Li Y, Lin JLC, Lin JJC. Tropomyosin and caldesmon regulate cytokinesis speed and membrane stability during cell division. Arch Biochem Biophys 2006; 456:161-74. [PMID: 16854366 DOI: 10.1016/j.abb.2006.06.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2006] [Revised: 06/14/2006] [Accepted: 06/15/2006] [Indexed: 01/11/2023]
Abstract
The contractile ring and the cell cortex generate force to divide the cell while maintaining symmetrical shape. This requires temporal and spatial regulation of the actin cytoskeleton at these areas. We force-expressed misregulated versions of actin-binding proteins, tropomyosin and caldesmon, into cells and analyzed their effects on cell division. Cells expressing proteins that increase actomyosin ATPase, such as human tropomyosin chimera (hTM5/3), significantly speed up division, whereas cells expressing proteins that inhibit actomyosin, such as caldesmon mutants defective in Ca(2+)/calmodulin binding (CaD39-AB) and in cdk1 phosphorylation sites (CaD39-6F), divide slowly. hTM5 and hTM5/3-expressing cells lift one daughter cell off the substrate and twist. Furthermore, CaD39-AB- and CaD39-6F-expressing cells are sensitive to hypotonic swelling and show severe blebbing during division, whereas hTM5/3-expressing cells are resistant to hypotonic swelling and produce membrane bulges. These results support a model where Ca(2+)/calmodulin and cdk1 dynamically control caldesmon inhibition of tropomyosin-activated actomyosin to regulate division speed and to suppress membrane blebs.
Collapse
Affiliation(s)
- Robbin D Eppinga
- Department of Biological Sciences, University of Iowa, Iowa City, IA 52242, USA
| | | | | | | |
Collapse
|
47
|
Effler JC, Kee YS, Berk JM, Tran MN, Iglesias PA, Robinson DN. Mitosis-specific mechanosensing and contractile-protein redistribution control cell shape. Curr Biol 2006; 16:1962-7. [PMID: 17027494 PMCID: PMC2474462 DOI: 10.1016/j.cub.2006.08.027] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2006] [Revised: 08/08/2006] [Accepted: 08/09/2006] [Indexed: 11/21/2022]
Abstract
Because cell-division failure is deleterious, promoting tumorigenesis in mammals, cells utilize numerous mechanisms to control their cell-cycle progression. Though cell division is considered a well-ordered sequence of biochemical events, cytokinesis, an inherently mechanical process, must also be mechanically controlled to ensure that two equivalent daughter cells are produced with high fidelity. Given that cells respond to their mechanical environment, we hypothesized that cells utilize mechanosensing and mechanical feedback to sense and correct shape asymmetries during cytokinesis. Because the mitotic spindle and myosin II are vital to cell division, we explored their roles in responding to shape perturbations during cell division. We demonstrate that the contractile proteins myosin II and cortexillin I redistribute in response to intrinsic and externally induced shape asymmetries. In early cytokinesis, mechanical load overrides spindle cues and slows cytokinesis progression while contractile proteins accumulate and correct shape asymmetries. In late cytokinesis, mechanical perturbation also directs contractile proteins but without apparently disrupting cytokinesis. Significantly, this response only occurs during anaphase through cytokinesis, does not require microtubules, and is independent of spindle orientation, but is dependent on myosin II. Our data provide evidence for a mechanosensory system that directs contractile proteins to regulate cell shape during mitosis.
Collapse
Affiliation(s)
- Janet C. Effler
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205
- Department of Electrical and Computer Engineering, Johns Hopkins University Whiting School of Engineering, 725 N. Wolfe St., Baltimore, MD 21205
| | - Yee-Seir Kee
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205
| | - Jason M. Berk
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205
| | - Minhchau N. Tran
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205
| | - Pablo A. Iglesias
- Department of Electrical and Computer Engineering, Johns Hopkins University Whiting School of Engineering, 725 N. Wolfe St., Baltimore, MD 21205
| | - Douglas N. Robinson
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205
- To whom correspondence should be addressed:
| |
Collapse
|
48
|
Carlsson AE. Contractile stress generation by actomyosin gels. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:051912. [PMID: 17279944 DOI: 10.1103/physreve.74.051912] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Revised: 08/24/2006] [Indexed: 05/13/2023]
Abstract
The tension generated by randomly distributed myosin minifilaments in an actin gel is evaluated using a rigorous theorem relating the surface forces acting on the gel to the forces exerted by the myosins. The maximum tension generated per myosin depends strongly on the lengths of the myosin minifilaments and the actin filaments. The result is used to place an upper bound on the tension that can be generated during cytokinesis. It is found that actomyosin contraction by itself generates too little force for ring contraction during cytokinesis unless the actin filaments are tightly crosslinked into inextensible units much longer than a single actin filament.
Collapse
Affiliation(s)
- A E Carlsson
- Department of Physics, Washington University, St. Louis, Missouri 63130, USA
| |
Collapse
|
49
|
Octtaviani E, Effler JC, Robinson DN. Enlazin, a natural fusion of two classes of canonical cytoskeletal proteins, contributes to cytokinesis dynamics. Mol Biol Cell 2006; 17:5275-86. [PMID: 17050732 PMCID: PMC1679690 DOI: 10.1091/mbc.e06-08-0767] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Cytokinesis requires a complex network of equatorial and global proteins to regulate cell shape changes. Here, using interaction genetics, we report the first characterization of a novel protein, enlazin. Enlazin is a natural fusion of two canonical classes of actin-associated proteins, the ezrin-radixin-moesin family and fimbrin, and it is localized to actin-rich structures. A fragment of enlazin, enl-tr, was isolated as a genetic suppressor of the cytokinesis defect of cortexillin-I mutants. Expression of enl-tr disrupts expression of endogenous enlazin, indicating that enl-tr functions as a dominant-negative lesion. Enlazin is distributed globally during cytokinesis and is required for cortical tension and cell adhesion. Consistent with a role in cell mechanics, inhibition of enlazin in a cortexillin-I background restores cytokinesis furrowing dynamics and suppresses the growth-in-suspension defect. However, as expected for a role in cell adhesion, inhibiting enlazin in a myosin-II background induces a synthetic cytokinesis phenotype, frequently arresting furrow ingression at the dumbbell shape and/or causing recession of the furrow. Thus, enlazin has roles in cell mechanics and adhesion, and these roles seem to be differentially significant for cytokinesis, depending on the genetic background.
Collapse
Affiliation(s)
- Edelyn Octtaviani
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Janet C. Effler
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205
| | - Douglas N. Robinson
- Department of Cell Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205
| |
Collapse
|
50
|
Lucero A, Stack C, Bresnick AR, Shuster CB. A global, myosin light chain kinase-dependent increase in myosin II contractility accompanies the metaphase-anaphase transition in sea urchin eggs. Mol Biol Cell 2006; 17:4093-104. [PMID: 16837551 PMCID: PMC1593176 DOI: 10.1091/mbc.e06-02-0119] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Revised: 06/15/2006] [Accepted: 07/05/2006] [Indexed: 11/11/2022] Open
Abstract
Myosin II is the force-generating motor for cytokinesis, and although it is accepted that myosin contractility is greatest at the cell equator, the temporal and spatial cues that direct equatorial contractility are not known. Dividing sea urchin eggs were placed under compression to study myosin II-based contractile dynamics, and cells manipulated in this manner underwent an abrupt, global increase in cortical contractility concomitant with the metaphase-anaphase transition, followed by a brief relaxation and the onset of furrowing. Prefurrow cortical contractility both preceded and was independent of astral microtubule elongation, suggesting that the initial activation of myosin II preceded cleavage plane specification. The initial rise in contractility required myosin light chain kinase but not Rho-kinase, but both signaling pathways were required for successful cytokinesis. Last, mobilization of intracellular calcium during metaphase induced a contractile response, suggesting that calcium transients may be partially responsible for the timing of this initial contractile event. Together, these findings suggest that myosin II-based contractility is initiated at the metaphase-anaphase transition by Ca2+-dependent myosin light chain kinase (MLCK) activity and is maintained through cytokinesis by both MLCK- and Rho-dependent signaling. Moreover, the signals that initiate myosin II contractility respond to specific cell cycle transitions independently of the microtubule-dependent cleavage stimulus.
Collapse
Affiliation(s)
- Amy Lucero
- Department of Biology, New Mexico State University, Las Cruces, NM 88003, USA
| | | | | | | |
Collapse
|