1
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Xu M, Rutkowski DM, Rebowski G, Boczkowska M, Pollard LW, Dominguez R, Vavylonis D, Ostap EM. Myosin-I synergizes with Arp2/3 complex to enhance the pushing forces of branched actin networks. SCIENCE ADVANCES 2024; 10:eado5788. [PMID: 39270022 PMCID: PMC11397503 DOI: 10.1126/sciadv.ado5788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Accepted: 08/09/2024] [Indexed: 09/15/2024]
Abstract
Class I myosins (myosin-Is) colocalize with Arp2/3 complex-nucleated actin networks at sites of membrane protrusion and invagination, but the mechanisms by which myosin-I motor activity coordinates with branched actin assembly to generate force are unknown. We mimicked the interplay of these proteins using the "comet tail" bead motility assay, where branched actin networks are nucleated by the Arp2/3 complex on the surface of beads coated with myosin-I and nucleation-promoting factor. We observed that myosin-I increased bead movement efficiency by thinning actin networks without affecting growth rates. Myosin-I triggered symmetry breaking and comet tail formation in dense networks resistant to spontaneous fracturing. Even with arrested actin assembly, myosin-I alone could break the network. Computational modeling recapitulated these observations, suggesting myosin-I acts as a repulsive force shaping the network's architecture and boosting its force-generating capacity. We propose that myosin-I leverages its power stroke to amplify the forces generated by Arp2/3 complex-nucleated actin networks.
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Affiliation(s)
- Mengqi Xu
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Grzegorz Rebowski
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Luther W. Pollard
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - E. Michael Ostap
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Salvadori A, Bonanno C, Serpelloni M, McMeeking RM. On the generation of force required for actin-based motility. Sci Rep 2024; 14:18384. [PMID: 39117762 PMCID: PMC11310465 DOI: 10.1038/s41598-024-69422-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 08/05/2024] [Indexed: 08/10/2024] Open
Abstract
The fundamental question of how forces are generated in a motile cell, a lamellipodium, and a comet tail is the subject of this note. It is now well established that cellular motility results from the polymerization of actin, the most abundant protein in eukaryotic cells, into an interconnected set of filaments. We portray this process in a continuum mechanics framework, claiming that polymerization promotes a mechanical swelling in a narrow zone around the nucleation loci, which ultimately results in cellular or bacterial motility. To this aim, a new paradigm in continuum multi-physics has been designed, departing from the well-known theory of Larché-Cahn chemo-transport-mechanics. In this note, we set up the theory of network growth and compare the outcomes of numerical simulations with experimental evidence.
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Affiliation(s)
- Alberto Salvadori
- The Mechanobiology Research Center, UNIBS, 25123, Brescia, Italy.
- Department of Mechanical and Industrial Engineering, Università degli Studi di Brescia, via Branze 38, 25123, Brescia, Italy.
| | - Claudia Bonanno
- The Mechanobiology Research Center, UNIBS, 25123, Brescia, Italy
| | - Mattia Serpelloni
- The Mechanobiology Research Center, UNIBS, 25123, Brescia, Italy
- Department of Mechanical and Industrial Engineering, Università degli Studi di Brescia, via Branze 38, 25123, Brescia, Italy
| | - Robert M McMeeking
- The Mechanobiology Research Center, UNIBS, 25123, Brescia, Italy
- Materials and Mechanical Engineering Departments, University of California, Santa Barbara, CA, 93106, USA
- School of Engineering, University of Aberdeen, King's College, Aberdeen, AB24 3UE, UK
- INM - Leibniz Institute for New Materials, Campus D2 2, Saarbruecken, Germany
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3
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Medina-Ruíz GI, Medina-Ruiz AI, Morán J. Fraping: A computational tool for detecting slight differences in fluorescence recovery after photobleaching (FRAP) data for actin polymerization analysis. Microsc Res Tech 2024; 87:1541-1551. [PMID: 38425281 DOI: 10.1002/jemt.24533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
Fluorescence recovery after photobleaching (FRAP) is a laser method of light microscopy to evaluate the rapid movement of fluorescent molecules. To have a more reliable approach to analyze data from FRAP, we designed Fraping, a free access R library to data analysis obtained from FRAP. Unlike other programs, Fraping has a new form of analyzing curves of FRAP using statistical analysis based on the average curve difference. To evaluate our library, we analyzed the differences of actin polymerization in real time between dendrites and secondary neurites of cultured neuron transfected with LifeAct to track F-actin changes of neurites. We found that Fraping provided greater sensitivity than the conventional model using mobile fraction analysis. Likewise, this approach allowed us to normalize the fluorescence to the size area of interest and adjust data curves choosing the best parametric model. In addition, this library was supplemented with data simulation to have a more significant enrichment for the analysis behavior. We concluded that Fraping is a method that reduces bias when analyzing two data groups as compared with the conventional methods. This method also allows the users to choose a more suitable analysis approach according to their requirements. RESEARCH HIGHLIGHTS: Fraping is a new programming tool to analyze FRAP data to normalize fluorescence recovery curves. The conventional method uses one-point analysis, and the new one compares all the points to define the similarity of the fluorescence recovery.
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Affiliation(s)
- Gabriela Itzetl Medina-Ruíz
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Posgrado en Ciencias Biológicas, Unidad de Posgrado, Ciudad Universitaria, Mexico City, Mexico
| | | | - Julio Morán
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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4
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Lee CT, Bell M, Bonilla-Quintana M, Rangamani P. Biophysical Modeling of Synaptic Plasticity. Annu Rev Biophys 2024; 53:397-426. [PMID: 38382115 DOI: 10.1146/annurev-biophys-072123-124954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Dendritic spines are small, bulbous compartments that function as postsynaptic sites and undergo intense biochemical and biophysical activity. The role of the myriad signaling pathways that are implicated in synaptic plasticity is well studied. A recent abundance of quantitative experimental data has made the events associated with synaptic plasticity amenable to quantitative biophysical modeling. Spines are also fascinating biophysical computational units because spine geometry, signal transduction, and mechanics work in a complex feedback loop to tune synaptic plasticity. In this sense, ideas from modeling cell motility can inspire us to develop multiscale approaches for predictive modeling of synaptic plasticity. In this article, we review the key steps in postsynaptic plasticity with a specific focus on the impact of spine geometry on signaling, cytoskeleton rearrangement, and membrane mechanics. We summarize the main experimental observations and highlight how theory and computation can aid our understanding of these complex processes.
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Affiliation(s)
- Christopher T Lee
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Miriam Bell
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Mayte Bonilla-Quintana
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA;
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5
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Tsai FC, Guérin G, Pernier J, Bassereau P. Actin-membrane linkers: Insights from synthetic reconstituted systems. Eur J Cell Biol 2024; 103:151402. [PMID: 38461706 DOI: 10.1016/j.ejcb.2024.151402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/10/2024] [Accepted: 02/28/2024] [Indexed: 03/12/2024] Open
Abstract
At the cell surface, the actin cytoskeleton and the plasma membrane interact reciprocally in a variety of processes related to the remodeling of the cell surface. The actin cytoskeleton has been known to modulate membrane organization and reshape the membrane. To this end, actin-membrane linking molecules play a major role in regulating actin assembly and spatially direct the interaction between the actin cytoskeleton and the membrane. While studies in cells have provided a wealth of knowledge on the molecular composition and interactions of the actin-membrane interface, the complex molecular interactions make it challenging to elucidate the precise actions of the actin-membrane linkers at the interface. Synthetic reconstituted systems, consisting of model membranes and purified proteins, have been a powerful approach to elucidate how actin-membrane linkers direct actin assembly to drive membrane shape changes. In this review, we will focus only on several actin-membrane linkers that have been studied by using reconstitution systems. We will discuss the design principles of these reconstitution systems and how they have contributed to the understanding of the cellular functions of actin-membrane linkers. Finally, we will provide a perspective on future research directions in understanding the intricate actin-membrane interaction.
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Affiliation(s)
- Feng-Ching Tsai
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
| | - Gwendal Guérin
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France
| | - Julien Pernier
- Tumor Cell Dynamics Unit, Inserm U1279, Gustave Roussy Institute, Université Paris-Saclay, Villejuif 94800, France
| | - Patricia Bassereau
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Physics of Cells and Cancer, Paris 75005, France.
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6
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Wang S, Ma S, Li H, Dao M, Li X, Karniadakis GE. Two-component macrophage model for active phagocytosis with pseudopod formation. Biophys J 2024; 123:1069-1084. [PMID: 38532625 PMCID: PMC11079866 DOI: 10.1016/j.bpj.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/20/2023] [Accepted: 03/21/2024] [Indexed: 03/28/2024] Open
Abstract
Macrophage phagocytosis is critical for the immune response, homeostasis regulation, and tissue repair. This intricate process involves complex changes in cell morphology, cytoskeletal reorganization, and various receptor-ligand interactions controlled by mechanical constraints. However, there is a lack of comprehensive theoretical and computational models that investigate the mechanical process of phagocytosis in the context of cytoskeletal rearrangement. To address this issue, we propose a novel coarse-grained mesoscopic model that integrates a fluid-like cell membrane and a cytoskeletal network to study the dynamic phagocytosis process. The growth of actin filaments results in the formation of long and thin pseudopods, and the initial cytoskeleton can be disassembled upon target entry and reconstructed after phagocytosis. Through dynamic changes in the cytoskeleton, our macrophage model achieves active phagocytosis by forming a phagocytic cup utilizing pseudopods in two distinct ways. We have developed a new algorithm for modifying membrane area to prevent membrane rupture and ensure sufficient surface area during phagocytosis. In addition, the bending modulus, shear stiffness, and cortical tension of the macrophage model are investigated through computation of the axial force for the tubular structure and micropipette aspiration. With this model, we simulate active phagocytosis at the cytoskeletal level and investigate the mechanical process during the dynamic interplay between macrophage and target particles.
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Affiliation(s)
- Shuo Wang
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuhao Ma
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China.
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7
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Guo J, Shao Y. Actin pushes open a leaky lumen. Cell Stem Cell 2024; 31:587-588. [PMID: 38701753 DOI: 10.1016/j.stem.2024.04.003] [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: 03/30/2024] [Revised: 04/03/2024] [Accepted: 04/03/2024] [Indexed: 05/05/2024]
Abstract
Using a human stem cell-based model to understand how the human epiblast forms at the very beginning of implantation, Indana et al.1 establish a role for pushing forces that are generated by apical actin polymerization and reveal a two-stage, biomechanics-driven lumen growth process underlying epiblast cavity morphogenesis.
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Affiliation(s)
- Jia Guo
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China
| | - Yue Shao
- Institute of Biomechanics and Medical Engineering, Applied Mechanics Laboratory, Department of Engineering Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing 100084, China.
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8
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Brückner DB, Broedersz CP. Learning dynamical models of single and collective cell migration: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2024; 87:056601. [PMID: 38518358 DOI: 10.1088/1361-6633/ad36d2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 03/22/2024] [Indexed: 03/24/2024]
Abstract
Single and collective cell migration are fundamental processes critical for physiological phenomena ranging from embryonic development and immune response to wound healing and cancer metastasis. To understand cell migration from a physical perspective, a broad variety of models for the underlying physical mechanisms that govern cell motility have been developed. A key challenge in the development of such models is how to connect them to experimental observations, which often exhibit complex stochastic behaviours. In this review, we discuss recent advances in data-driven theoretical approaches that directly connect with experimental data to infer dynamical models of stochastic cell migration. Leveraging advances in nanofabrication, image analysis, and tracking technology, experimental studies now provide unprecedented large datasets on cellular dynamics. In parallel, theoretical efforts have been directed towards integrating such datasets into physical models from the single cell to the tissue scale with the aim of conceptualising the emergent behaviour of cells. We first review how this inference problem has been addressed in both freely migrating and confined cells. Next, we discuss why these dynamics typically take the form of underdamped stochastic equations of motion, and how such equations can be inferred from data. We then review applications of data-driven inference and machine learning approaches to heterogeneity in cell behaviour, subcellular degrees of freedom, and to the collective dynamics of multicellular systems. Across these applications, we emphasise how data-driven methods can be integrated with physical active matter models of migrating cells, and help reveal how underlying molecular mechanisms control cell behaviour. Together, these data-driven approaches are a promising avenue for building physical models of cell migration directly from experimental data, and for providing conceptual links between different length-scales of description.
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Affiliation(s)
- David B Brückner
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Chase P Broedersz
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
- Arnold Sommerfeld Center for Theoretical Physics and Center for NanoScience, Department of Physics, Ludwig-Maximilian-University Munich, Theresienstr. 37, D-80333 Munich, Germany
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9
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Bonilla-Quintana M, Rangamani P. Biophysical Modeling of Actin-Mediated Structural Plasticity Reveals Mechanical Adaptation in Dendritic Spines. eNeuro 2024; 11:ENEURO.0497-23.2024. [PMID: 38383589 DOI: 10.1523/eneuro.0497-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/13/2024] [Indexed: 02/23/2024] Open
Abstract
Synaptic plasticity is important for learning and memory formation; it describes the strengthening or weakening of connections between synapses. The postsynaptic part of excitatory synapses resides in dendritic spines, which are small protrusions on the dendrites. One of the key features of synaptic plasticity is its correlation with the size of these spines. A long-lasting synaptic strength increase [long-term potentiation (LTP)] is only possible through the reconfiguration of the actin spine cytoskeleton. Here, we develop an experimentally informed three-dimensional computational model in a moving boundary framework to investigate this reconfiguration. Our model describes the reactions between actin and actin-binding proteins leading to the cytoskeleton remodeling and their effect on the spine membrane shape to examine the spine enlargement upon LTP. Moreover, we find that the incorporation of perisynaptic elements enhances spine enlargement upon LTP, exhibiting the importance of accounting for these elements when studying structural LTP. Our model shows adaptation to repeated stimuli resulting from the interactions between spine proteins and mechanical forces.
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Affiliation(s)
- Mayte Bonilla-Quintana
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093
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10
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Chennakesavalu S, Manikandan SK, Hu F, Rotskoff GM. Adaptive nonequilibrium design of actin-based metamaterials: Fundamental and practical limits of control. Proc Natl Acad Sci U S A 2024; 121:e2310238121. [PMID: 38359294 PMCID: PMC10895351 DOI: 10.1073/pnas.2310238121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 11/13/2023] [Indexed: 02/17/2024] Open
Abstract
The adaptive and surprising emergent properties of biological materials self-assembled in far-from-equilibrium environments serve as an inspiration for efforts to design nanomaterials. In particular, controlling the conditions of self-assembly can modulate material properties, but there is no systematic understanding of either how to parameterize external control or how controllable a given material can be. Here, we demonstrate that branched actin networks can be encoded with metamaterial properties by dynamically controlling the applied force under which they grow and that the protocols can be selected using multi-task reinforcement learning. These actin networks have tunable responses over a large dynamic range depending on the chosen external protocol, providing a pathway to encoding "memory" within these structures. Interestingly, we obtain a bound that relates the dissipation rate and the rate of "encoding" that gives insight into the constraints on control-both physical and information theoretical. Taken together, these results emphasize the utility and necessity of nonequilibrium control for designing self-assembled nanostructures.
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Affiliation(s)
| | | | - Frank Hu
- Department of Chemistry, Stanford University, Stanford, CA94305
| | - Grant M. Rotskoff
- Department of Chemistry, Stanford University, Stanford, CA94305
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA94305
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11
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Xu M, Rutkowski DM, Rebowski G, Boczkowska M, Pollard LW, Dominguez R, Vavylonis D, Ostap EM. Myosin-I Synergizes with Arp2/3 Complex to Enhance Pushing Forces of Branched Actin Networks. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579714. [PMID: 38405741 PMCID: PMC10888859 DOI: 10.1101/2024.02.09.579714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Myosin-Is colocalize with Arp2/3 complex-nucleated actin networks at sites of membrane protrusion and invagination, but the mechanisms by which myosin-I motor activity coordinates with branched actin assembly to generate force are unknown. We mimicked the interplay of these proteins using the "comet tail" bead motility assay, where branched actin networks are nucleated by Arp2/3 complex on the surface of beads coated with myosin-I and the WCA domain of N-WASP. We observed that myosin-I increased bead movement efficiency by thinning actin networks without affecting growth rates. Remarkably, myosin-I triggered symmetry breaking and comet-tail formation in dense networks resistant to spontaneous fracturing. Even with arrested actin assembly, myosin-I alone could break the network. Computational modeling recapitulated these observations suggesting myosin-I acts as a repulsive force shaping the network's architecture and boosting its force-generating capacity. We propose that myosin-I leverages its power stroke to amplify the forces generated by Arp2/3 complex-nucleated actin networks.
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Affiliation(s)
- Mengqi Xu
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - Grzegorz Rebowski
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Malgorzata Boczkowska
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Luther W Pollard
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Roberto Dominguez
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | | | - E Michael Ostap
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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12
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Qiu Z, Minegishi T, Aoki D, Abe K, Baba K, Inagaki N. Adhesion-clutch between DCC and netrin-1 mediates netrin-1-induced axonal haptotaxis. Front Mol Neurosci 2024; 17:1307755. [PMID: 38375502 PMCID: PMC10875621 DOI: 10.3389/fnmol.2024.1307755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/08/2024] [Indexed: 02/21/2024] Open
Abstract
The growth cone, a motile structure located at the tip of growing axons, senses extracellular guidance cues and translates them into directional forces that drive axon outgrowth and guidance. Axon guidance directed by chemical cues on the extracellular adhesive substrate is termed haptotaxis. Recent studies reported that netrin-1 on the substrate functions as a haptotactic axon guidance cue. However, the mechanism mediating netrin-1-induced axonal haptotaxis remains unclear. Here, we demonstrate that substrate-bound netrin-1 induces axonal haptotaxis by facilitating physical interactions between the netrin-1 receptor, DCC, and the adhesive substrates. DCC serves as an adhesion receptor for netrin-1. The clutch-linker molecule shootin1a interacted with DCC, linking it to actin filament retrograde flow at the growth cone. Speckle imaging analyses showed that DCC underwent either grip (stop) or retrograde slip on the adhesive substrate. The grip state was more prevalent on netrin-1-coated substrate compared to the control substrate polylysine, thereby transmitting larger traction force on the netrin-1-coated substrate. Furthermore, disruption of the linkage between actin filament retrograde flow and DCC by shootin1 knockout impaired netrin-1-induced axonal haptotaxis. These results suggest that the directional force for netrin-1-induced haptotaxis is exerted on the substrates through the adhesion-clutch between DCC and netrin-1 which occurs asymmetrically within the growth cone.
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Affiliation(s)
| | | | | | | | | | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
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13
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Larson BT. Perspectives on Principles of Cellular Behavior from the Biophysics of Protists. Integr Comp Biol 2023; 63:1405-1421. [PMID: 37496203 PMCID: PMC10755178 DOI: 10.1093/icb/icad106] [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: 03/22/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023] Open
Abstract
Cells are the fundamental unit of biological organization. Although it may be easy to think of them as little more than the simple building blocks of complex organisms such as animals, single cells are capable of behaviors of remarkable apparent sophistication. This is abundantly clear when considering the diversity of form and function among the microbial eukaryotes, the protists. How might we navigate this diversity in the search for general principles of cellular behavior? Here, we review cases in which the intensive study of protists from the perspective of cellular biophysics has driven insight into broad biological questions of morphogenesis, navigation and motility, and decision making. We argue that applying such approaches to questions of evolutionary cell biology presents rich, emerging opportunities. Integrating and expanding biophysical studies across protist diversity, exploiting the unique characteristics of each organism, will enrich our understanding of general underlying principles.
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Affiliation(s)
- Ben T Larson
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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14
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Bedi A, Choi K, Keane C, Bolger-Munro M, Ambrose AR, Gold MR. WAVE2 Regulates Actin-Dependent Processes Induced by the B Cell Antigen Receptor and Integrins. Cells 2023; 12:2704. [PMID: 38067132 PMCID: PMC10705906 DOI: 10.3390/cells12232704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/22/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
B cell antigen receptor (BCR) signaling induces actin cytoskeleton remodeling by stimulating actin severing, actin polymerization, and the nucleation of branched actin networks via the Arp2/3 complex. This enables B cells to spread on antigen-bearing surfaces in order to increase antigen encounters and to form an immune synapse (IS) when interacting with antigen-presenting cells (APCs). Although the WASp, N-WASp, and WAVE nucleation-promoting factors activate the Arp2/3 complex, the role of WAVE2 in B cells has not been directly assessed. We now show that both WAVE2 and the Arp2/3 complex localize to the peripheral ring of branched F-actin when B cells spread on immobilized anti-Ig antibodies. The siRNA-mediated depletion of WAVE2 reduced and delayed B cell spreading on immobilized anti-Ig, and this was associated with a thinner peripheral F-actin ring and reduced actin retrograde flow compared to control cells. Depleting WAVE2 also impaired integrin-mediated B cell spreading on fibronectin and the LFA-1-induced formation of actomyosin arcs. Actin retrograde flow amplifies BCR signaling at the IS, and we found that depleting WAVE2 reduced microcluster-based BCR signaling and signal amplification at the IS, as well as B cell activation in response to antigen-bearing cells. Hence, WAVE2 contributes to multiple actin-dependent processes in B lymphocytes.
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Affiliation(s)
- Abhishek Bedi
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
| | - Kate Choi
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
| | - Connor Keane
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
| | - Madison Bolger-Munro
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
| | - Ashley R Ambrose
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
| | - Michael R Gold
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada
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15
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Carney KR, Khan AM, Stam S, Samson SC, Mittal N, Han SJ, Bidone TC, Mendoza MC. Nascent adhesions shorten the period of lamellipodium protrusion through the Brownian ratchet mechanism. Mol Biol Cell 2023; 34:ar115. [PMID: 37672339 PMCID: PMC10846621 DOI: 10.1091/mbc.e23-08-0314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 08/22/2023] [Indexed: 09/08/2023] Open
Abstract
Directional cell migration is driven by the conversion of oscillating edge motion into lasting periods of leading edge protrusion. Actin polymerization against the membrane and adhesions control edge motion, but the exact mechanisms that determine protrusion period remain elusive. We addressed this by developing a computational model in which polymerization of actin filaments against a deformable membrane and variable adhesion dynamics support edge motion. Consistent with previous reports, our model showed that actin polymerization and adhesion lifetime power protrusion velocity. However, increasing adhesion lifetime decreased the protrusion period. Measurements of adhesion lifetime and edge motion in migrating cells confirmed that adhesion lifetime is associated with and promotes protrusion velocity, but decreased duration. Our model showed that adhesions' control of protrusion persistence originates from the Brownian ratchet mechanism for actin filament polymerization. With longer adhesion lifetime or increased-adhesion density, the proportion of actin filaments tethered to the substrate increased, maintaining filaments against the cell membrane. The reduced filament-membrane distance generated pushing force for high edge velocity, but limited further polymerization needed for protrusion duration. We propose a mechanism for cell edge protrusion in which adhesion strength regulates actin filament polymerization to control the periods of leading edge protrusion.
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Affiliation(s)
- Keith R. Carney
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, Salt Lake City, UT 84112
| | - Akib M. Khan
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, Salt Lake City, UT 84112
| | - Samantha Stam
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, Salt Lake City, UT 84112
| | - Shiela C. Samson
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, Salt Lake City, UT 84112
| | - Nikhil Mittal
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931
| | - Sangyoon J. Han
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931
| | - Tamara C. Bidone
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112
- Scientific Computing and Imaging Institute, Salt Lake City, UT 84112
| | - Michelle C. Mendoza
- Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84112
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112
- Huntsman Cancer Institute, Salt Lake City, UT 84112
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16
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Ditto M, Jacho D, Eisenmann KM, Yildirim-Ayan E. Extracellular Mechanical Stimuli Alters the Metastatic Progression of Prostate Cancer Cells within 3D Tissue Matrix. Bioengineering (Basel) 2023; 10:1271. [PMID: 38002395 PMCID: PMC10669840 DOI: 10.3390/bioengineering10111271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/19/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
This study aimed to understand extracellular mechanical stimuli's effect on prostate cancer cells' metastatic progression within a three-dimensional (3D) bone-like microenvironment. In this study, a mechanical loading platform, EQUicycler, has been employed to create physiologically relevant static and cyclic mechanical stimuli to a prostate cancer cell (PC-3)-embedded 3D tissue matrix. Three mechanical stimuli conditions were applied: control (no loading), cyclic (1% strain at 1 Hz), and static mechanical stimuli (1% strain). The changes in prostate cancer cells' cytoskeletal reorganization, polarity (elongation index), proliferation, expression level of N-Cadherin (metastasis-associated gene), and migratory potential within the 3D collagen structures were assessed upon mechanical stimuli. The results have shown that static mechanical stimuli increased the metastasis progression factors, including cell elongation (p < 0.001), cellular F-actin accumulation (p < 0.001), actin polymerization (p < 0.001), N-Cadherin gene expression, and invasion capacity of PC-3 cells within a bone-like microenvironment compared to its cyclic and control loading counterparts. This study established a novel system for studying metastatic cancer cells within bone and enables the creation of biomimetic in vitro models for cancer research and mechanobiology.
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Affiliation(s)
- Maggie Ditto
- Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH 43606, USA
| | - Diego Jacho
- Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH 43606, USA
| | - Kathryn M. Eisenmann
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, University of Toledo Health Science Campus, Toledo, OH 43614, USA
| | - Eda Yildirim-Ayan
- Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH 43606, USA
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17
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Shrivastava A, Du Y, Adepu HK, Li R, Madhvacharyula AS, Swett AA, Choi JH. Motility of Synthetic Cells from Engineered Lipids. ACS Synth Biol 2023; 12:2789-2801. [PMID: 37729546 DOI: 10.1021/acssynbio.3c00271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Synthetic cells are artificial systems that resemble natural cells. Significant efforts have been made over the years to construct synthetic protocells that can mimic biological mechanisms and perform various complex processes. These include compartmentalization, metabolism, energy supply, communication, and gene reproduction. Cell motility is also of great importance, as nature uses elegant mechanisms for intracellular trafficking, immune response, and embryogenesis. In this review, we discuss the motility of synthetic cells made from lipid vesicles and relevant molecular mechanisms. Synthetic cell motion may be classified into surface-based or solution-based depending on whether it involves interactions with surfaces or movement in fluids. Collective migration behaviors have also been demonstrated. The swarm motion requires additional mechanisms for intercellular signaling and directional motility that enable communication and coordination among the synthetic vesicles. In addition, intracellular trafficking for molecular transport has been reconstituted in minimal cells with the help of DNA nanotechnology. These efforts demonstrate synthetic cells that can move, detect, respond, and interact. We envision that new developments in protocell motility will enhance our understanding of biological processes and be instrumental in bioengineering and therapeutic applications.
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Affiliation(s)
- Aishwary Shrivastava
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Yancheng Du
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Harshith K Adepu
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Ruixin Li
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Anirudh S Madhvacharyula
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
| | - Alexander A Swett
- School of Mechanical Engineering, Purdue University, Neil Armstrong Hall of Engineering, 701 W. Stadium Avenue, West Lafayette, Indiana 47907, United States
| | - Jong Hyun Choi
- School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, Indiana 47907, United States
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18
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Gonthier A, Botvinick EL, Grosberg A, Mohraz A. Effect of Porous Substrate Topographies on Cell Dynamics: A Computational Study. ACS Biomater Sci Eng 2023; 9:5666-5678. [PMID: 37713253 PMCID: PMC10565724 DOI: 10.1021/acsbiomaterials.3c01008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 08/31/2023] [Indexed: 09/16/2023]
Abstract
Controlling cell-substrate interactions via the microstructural characteristics of biomaterials offers an advantageous path for modulating cell dynamics, mechanosensing, and migration, as well as for designing immune-modulating implants, all without the drawbacks of chemical-based triggers. Specifically, recent in vivo studies have suggested that a porous implant's microscale curvature landscape can significantly impact cell behavior and ultimately the immune response. To investigate such cell-substrate interactions, we utilized a 3D computational model incorporating the minimum necessary physics of cell migration and cell-substrate interactions needed to replicate known in vitro behaviors. This model specifically incorporates the effect of membrane tension, which was found to be necessary to replicate in vitro cell behavior on curved surfaces. Our simulated substrates represent two classes of porous materials recently used in implant studies, which have markedly different microscale curvature distributions and pore geometries. We found distinct differences between the overall migration behaviors, shapes, and actin polymerization dynamics of cells interacting with the two substrates. These differences were correlated to the shape energy of the cells as they interacted with the porous substrates, in effect interpreting substrate topography as an energetic landscape interrogated by cells. Our results demonstrate that microscale curvature directly influences cell shape and migration and, therefore, is likely to influence cell behavior. This supports further investigation of the relationship between the surface topography of implanted materials and the characteristic immune response, a complete understanding of which would broadly advance principles of biomaterial design.
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Affiliation(s)
- Alyse
R. Gonthier
- Department
of Materials Science & Engineering, University of California, Irvine, Irvine, California 92697, United States
| | - Elliot L. Botvinick
- Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States
- Center
for Complex Biological Systems, University
of California, Irvine, Irvine, California 92697, United States
- Beckman
Laser Institute and Medical Clinic, University
of California, Irvine, Irvine, California 92697, United States
- Department
of Surgery,University of California, Irvine, Irvine, California 92697, United States
- Edwards
Lifesciences
Foundation Cardiovascular Innovation & Research Center, University of California, Irvine, Irvine, California 92697, United States
| | - Anna Grosberg
- Department
of Biomedical Engineering, University of
California, Irvine, Irvine, California 92697, United States
- Center
for Complex Biological Systems, University
of California, Irvine, Irvine, California 92697, United States
- Edwards
Lifesciences
Foundation Cardiovascular Innovation & Research Center, University of California, Irvine, Irvine, California 92697, United States
- Department
of Chemical & Biomolecular Engineering, University of California, Irvine, Irvine, California 92697, United States
- The
NSF-Simons Center for Multiscale Cell Fate Research, University of California, Irvine, Irvine, California 92697, United States
- Sue
and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, California 92697, United States
| | - Ali Mohraz
- Department
of Materials Science & Engineering, University of California, Irvine, Irvine, California 92697, United States
- Department
of Chemical & Biomolecular Engineering, University of California, Irvine, Irvine, California 92697, United States
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19
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Pedersen RT, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. J Cell Biol 2023; 222:e202303095. [PMID: 37549220 PMCID: PMC10406613 DOI: 10.1083/jcb.202303095] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/17/2023] [Accepted: 07/24/2023] [Indexed: 08/09/2023] Open
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than that of slow anchoring myosin-1s found on endosomal membranes. We, therefore, propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells.
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Affiliation(s)
- Ross T.A. Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David G. Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - E. Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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20
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Gudimchuk NB, Alexandrova VV. Measuring and modeling forces generated by microtubules. Biophys Rev 2023; 15:1095-1110. [PMID: 37974983 PMCID: PMC10643784 DOI: 10.1007/s12551-023-01161-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 09/25/2023] [Indexed: 11/19/2023] Open
Abstract
Tubulins are essential proteins, which are conserved across all eukaryotic species. They polymerize to form microtubules, cytoskeletal components of paramount importance for cellular mechanics. The microtubules combine an extraordinarily high flexural rigidity and a non-equilibrium behavior, manifested in their intermittent assembly and disassembly. These chemically fueled dynamics allow microtubules to generate significant pushing and pulling forces at their ends to reposition intracellular organelles, remodel membranes, bear compressive forces, and transport chromosomes during cell division. In this article, we review classical and recent studies, which have allowed the quantification of microtubule-generated forces. The measurements, to which we owe most of the quantitative information about microtubule forces, were carried out in biochemically reconstituted systems in vitro. We also discuss how mathematical and computational modeling has contributed to the interpretations of these results and shaped our understanding of the mechanisms of force production by tubulin polymerization and depolymerization.
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Affiliation(s)
- Nikita B. Gudimchuk
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia
- Pskov State University, Pskov, Russia
| | - Veronika V. Alexandrova
- Department of Physics, Lomonosov Moscow State University, Moscow, Russia
- Department of Biology, Lomonosov Moscow State University, Moscow, Russia
- Center for Theoretical Problems of Physicochemical Pharmacology, Moscow, Russia
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21
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Appalabhotla R, Butler MT, Bear JE, Haugh JM. G-actin diffusion is insufficient to achieve F-actin assembly in fast-treadmilling protrusions. Biophys J 2023; 122:3816-3829. [PMID: 37644720 PMCID: PMC10541494 DOI: 10.1016/j.bpj.2023.08.022] [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: 04/01/2023] [Revised: 07/07/2023] [Accepted: 08/25/2023] [Indexed: 08/31/2023] Open
Abstract
To generate forces that drive migration of a eukaryotic cell, arrays of actin filaments (F-actin) are assembled at the cell's leading membrane edge. To maintain cell propulsion and respond to dynamic external cues, actin filaments must be disassembled to regenerate the actin monomers (G-actin), and transport of G-actin from sites of disassembly back to the leading edge completes the treadmilling cycle and limits the flux of F-actin assembly. Whether or not molecular diffusion is sufficient for G-actin transport has been a long-standing topic of debate, in part because the dynamic nature of cell motility and migration hinders the estimation of transport parameters. In this work, we applied an experimental system in which cells adopt an approximately constant and symmetrical shape; they cannot migrate but exhibit fast, steady treadmilling in the thin region protruding from the cell. Using fluorescence recovery after photobleaching, we quantified the relative concentrations and corresponding fluxes of F- and G-actin in this system. In conjunction with mathematical modeling, constrained by measured features of each region of interest, this approach revealed that diffusion alone cannot account for the transport of G-actin to the leading edge. Although G-actin diffusion and vectorial transport might vary with position in the protruding region, good agreement with the fluorescence recovery after photobleaching measurements was achieved by a model with constant G-actin diffusivity ∼2 μm2/s and anterograde G-actin velocity less than 1 μm/s.
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Affiliation(s)
- Ravikanth Appalabhotla
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina
| | - Mitchell T Butler
- Department of Cell Biology and Physiology, UNC Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina
| | - James E Bear
- Department of Cell Biology and Physiology, UNC Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, North Carolina.
| | - Jason M Haugh
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina.
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22
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Chen X, Li Y, Guo M, Xu B, Ma Y, Zhu H, Feng XQ. Polymerization force-regulated actin filament-Arp2/3 complex interaction dominates self-adaptive cell migrations. Proc Natl Acad Sci U S A 2023; 120:e2306512120. [PMID: 37639611 PMCID: PMC10483647 DOI: 10.1073/pnas.2306512120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 07/23/2023] [Indexed: 08/31/2023] Open
Abstract
Cells migrate by adapting their leading-edge behaviors to heterogeneous extracellular microenvironments (ECMs) during cancer invasions and immune responses. Yet it remains poorly understood how such complicated dynamic behaviors emerge from millisecond-scale assembling activities of protein molecules, which are hard to probe experimentally. To address this gap, we establish a spatiotemporal "resistance-adaptive propulsion" theory based on the interactions between Arp2/3 complexes and polymerizing actin filaments and a multiscale dynamic modeling system spanning from molecular proteins to the cell. We quantitatively find that cells can accurately self-adapt propulsive forces to overcome heterogeneous ECMs via a resistance-triggered positive feedback mechanism, dominated by polymerization-induced actin filament bending and the bending-regulated actin-Arp2/3 binding. However, for high resistance regions, resistance triggers a negative feedback, hindering branched filament assembly, which adapts cellular morphologies to circumnavigate the obstacles. Strikingly, the synergy of the two opposite feedbacks not only empowers the cell with both powerful and flexible migratory capabilities to deal with complex ECMs but also enables efficient utilization of intracellular proteins by the cell. In addition, we identify that the nature of cell migration velocity depending on ECM history stems from the inherent temporal hysteresis of cytoskeleton remodeling. We also show that directional cell migration is dictated by the competition between the local stiffness of ECMs and the local polymerizing rate of actin network caused by chemotactic cues. Our results reveal that it is the polymerization force-regulated actin filament-Arp2/3 complex binding interaction that dominates self-adaptive cell migrations in complex ECMs, and we provide a predictive theory and a spatiotemporal multiscale modeling system at the protein level.
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Affiliation(s)
- Xindong Chen
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Yuhui Li
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire et Végétale, Interdisciplinary Research Institute of Grenoble, Commissariat à l’Énergie Atomique et aux Énergies Alternatives/CNRS/Université Grenoble Alpes, Grenoble38054, France
| | - Ming Guo
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Bowen Xu
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
| | - Yanhui Ma
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Hanxing Zhu
- School of Engineering, Cardiff University, CardiffCF24 3AA, United Kingdom
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing100084, China
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23
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Singh Y, Hocky GM, Nolen BJ. Molecular dynamics simulations support a multistep pathway for activation of branched actin filament nucleation by Arp2/3 complex. J Biol Chem 2023; 299:105169. [PMID: 37595874 PMCID: PMC10514467 DOI: 10.1016/j.jbc.2023.105169] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/10/2023] [Accepted: 08/12/2023] [Indexed: 08/20/2023] Open
Abstract
Actin-related protein 2/3 complex (Arp2/3 complex) catalyzes the nucleation of branched actin filaments that push against membranes in processes like cellular motility and endocytosis. During activation by WASP proteins, the complex must bind WASP and engage the side of a pre-existing (mother) filament before a branched filament is nucleated. Recent high-resolution structures of activated Arp2/3 complex revealed two major sets of activating conformational changes. How these activating conformational changes are triggered by interactions of Arp2/3 complex with actin filaments and WASP remains unclear. Here we use a recent high-resolution structure of Arp2/3 complex at a branch junction to design all-atom molecular dynamics simulations that elucidate the pathway between the active and inactive states. We ran a total of ∼4.6 microseconds of both unbiased and steered all-atom molecular dynamics simulations starting from three different binding states, including Arp2/3 complex within a branch junction, bound only to a mother filament, and alone in solution. These simulations indicate that the contacts with the mother filament are mostly insensitive to the massive rigid body motion that moves Arp2 and Arp3 into a short pitch helical (filament-like) arrangement, suggesting actin filaments alone do not stimulate the short pitch conformational change. In contrast, contacts with the mother filament stabilize subunit flattening in Arp3, an intrasubunit change that converts Arp3 from a conformation that mimics an actin monomer to one that mimics a filamentous actin subunit. Our results support a multistep activation pathway that has important implications for understanding how WASP-mediated activation allows Arp2/3 complex to assemble force-producing actin networks.
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Affiliation(s)
| | - Glen M Hocky
- Department of Chemistry, New York University; Simons Center for Computational Physical Chemistry, New York University.
| | - Brad J Nolen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of Oregon.
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24
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Chandrasekar S, Beach JR, Oakes PW. Shining a light on RhoA: Optical control of cell contractility. Int J Biochem Cell Biol 2023; 161:106442. [PMID: 37348811 PMCID: PMC10530351 DOI: 10.1016/j.biocel.2023.106442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/10/2023] [Accepted: 06/19/2023] [Indexed: 06/24/2023]
Abstract
In addition to biochemical and electrochemical signaling, cells also rely extensively on mechanical signaling to regulate their behavior. While a number of tools have been adapted from physics and engineering to manipulate cell mechanics, they typically require specialized equipment or lack spatiotemporal precision. Alternatively, a recent, more elegant approach is to use light itself to modulate the mechanical equilibrium inside the cell. This approach leverages the power of optogenetics, which can be controlled in a fully reversible manner in both time and space, to tune RhoA signaling, the master regulator of cellular contractility. We review here the fundamentals of this approach, including illustrating the tunability and flexibility that optogenetics offers, and demonstrate how this tool can be used to modulate both internal cytoskeletal flows and contractile force generation. Together these features highlight the advantages that optogenetics offers for investigating mechanical interactions in cells.
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Affiliation(s)
- Shreya Chandrasekar
- Department of Cell & Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Jordan R Beach
- Department of Cell & Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Patrick W Oakes
- Department of Cell & Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA.
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25
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Sadhu RK, Iglič A, Gov NS. A minimal cell model for lamellipodia-based cellular dynamics and migration. J Cell Sci 2023; 136:jcs260744. [PMID: 37497740 DOI: 10.1242/jcs.260744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023] Open
Abstract
One ubiquitous cellular structure for performing various tasks, such as spreading and migration over external surfaces, is the sheet-like protrusion called a lamellipodium, which propels the leading edge of the cell. Despite the detailed knowledge about the many components of this cellular structure, it is not yet fully understood how these components self-organize spatiotemporally to form lamellipodia. We review here recent theoretical works where we have demonstrated that membrane-bound protein complexes that have intrinsic curvature and recruit the protrusive forces of the cytoskeleton result in a simple, yet highly robust, organizing feedback mechanism that organizes the cytoskeleton and the membrane. This self-organization mechanism accounts for the formation of flat lamellipodia at the leading edge of cells spreading over adhesive substrates, allowing for the emergence of a polarized, motile 'minimal cell' model. The same mechanism describes how lamellipodia organize to drive robust engulfment of particles during phagocytosis and explains in simple physical terms the spreading and migration of cells over fibers and other curved surfaces. This Review highlights that despite the complexity of cellular composition, there might be simple general physical principles that are utilized by the cell to drive cellular shape dynamics.
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Affiliation(s)
- Raj Kumar Sadhu
- Institut Curie, PSL Research University, CNRS, UMR 168, Paris 75005, France
| | - Aleš Iglič
- Laboratory of Physics, Faculty of Electrical Engineering, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Nir S Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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26
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Pedersen RTA, Snoberger A, Pyrpassopoulos S, Safer D, Drubin DG, Ostap EM. Endocytic myosin-1 is a force-insensitive, power-generating motor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.21.533689. [PMID: 36993306 PMCID: PMC10055380 DOI: 10.1101/2023.03.21.533689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Myosins are required for clathrin-mediated endocytosis, but their precise molecular roles in this process are not known. This is, in part, because the biophysical properties of the relevant motors have not been investigated. Myosins have diverse mechanochemical activities, ranging from powerful contractility against mechanical loads to force-sensitive anchoring. To better understand the essential molecular contribution of myosin to endocytosis, we studied the in vitro force-dependent kinetics of the Saccharomyces cerevisiae endocytic type I myosin called Myo5, a motor whose role in clathrin-mediated endocytosis has been meticulously studied in vivo. We report that Myo5 is a low-duty-ratio motor that is activated ∼10-fold by phosphorylation, and that its working stroke and actin-detachment kinetics are relatively force-insensitive. Strikingly, the in vitro mechanochemistry of Myo5 is more like that of cardiac myosin than like that of slow anchoring myosin-1s found on endosomal membranes. We therefore propose that Myo5 generates power to augment actin assembly-based forces during endocytosis in cells. Summary Pedersen, Snoberger et al. measure the force-sensitivity of the yeast endocytic the myosin-1 called Myo5 and find that it is more likely to generate power than to serve as a force-sensitive anchor in cells. Implications for Myo5's role in clathrin-mediated endocytosis are discussed.
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Affiliation(s)
- Ross TA Pedersen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
- Present address: Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
- Equal Contribution
| | - Aaron Snoberger
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
- Equal Contribution
| | - Serapion Pyrpassopoulos
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Daniel Safer
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - David G Drubin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - E Michael Ostap
- Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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27
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Gong Z, van den Dries K, Migueles-Ramírez RA, Wiseman PW, Cambi A, Shenoy VB. Chemo-mechanical diffusion waves explain collective dynamics of immune cell podosomes. Nat Commun 2023; 14:2902. [PMID: 37217555 PMCID: PMC10202956 DOI: 10.1038/s41467-023-38598-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/09/2023] [Indexed: 05/24/2023] Open
Abstract
Immune cells, such as macrophages and dendritic cells, can utilize podosomes, mechanosensitive actin-rich protrusions, to generate forces, migrate, and patrol for foreign antigens. Individual podosomes probe their microenvironment through periodic protrusion and retraction cycles (height oscillations), while oscillations of multiple podosomes in a cluster are coordinated in a wave-like fashion. However, the mechanisms governing both the individual oscillations and the collective wave-like dynamics remain unclear. Here, by integrating actin polymerization, myosin contractility, actin diffusion, and mechanosensitive signaling, we develop a chemo-mechanical model for podosome dynamics in clusters. Our model reveals that podosomes show oscillatory growth when actin polymerization-driven protrusion and signaling-associated myosin contraction occur at similar rates, while the diffusion of actin monomers drives wave-like coordination of podosome oscillations. Our theoretical predictions are validated by different pharmacological treatments and the impact of microenvironment stiffness on chemo-mechanical waves. Our proposed framework can shed light on the role of podosomes in immune cell mechanosensing within the context of wound healing and cancer immunotherapy.
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Affiliation(s)
- Ze Gong
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui, 230027, China
| | - Koen van den Dries
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rodrigo A Migueles-Ramírez
- Departments of Chemistry and Physics, McGill University, Montreal, QC, H3A 0B8, Canada
- Quantitative Life Sciences, McGill University, Montreal, QC, H3A 3R1, Canada
- Department of Biology, McGill University, Montreal, QC, H3G 0B1, Canada
| | - Paul W Wiseman
- Departments of Chemistry and Physics, McGill University, Montreal, QC, H3A 0B8, Canada
| | - Alessandra Cambi
- Department of Medical Biosciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Vivek B Shenoy
- Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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28
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Murali A, Sarkar RR. Mechano-immunology in microgravity. LIFE SCIENCES IN SPACE RESEARCH 2023; 37:50-64. [PMID: 37087179 DOI: 10.1016/j.lssr.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 02/16/2023] [Accepted: 03/05/2023] [Indexed: 05/03/2023]
Abstract
Life on Earth has evolved to thrive in the Earth's natural gravitational field; however, as space technology advances, we must revisit and investigate the effects of unnatural conditions on human health, such as gravitational change. Studies have shown that microgravity has a negative impact on various systemic parts of humans, with the effects being more severe in the human immune system. Increasing costs, limited experimental time, and sample handling issues hampered our understanding of this field. To address the existing knowledge gap and provide confidence in modelling the phenomena, in this review, we highlight experimental works in mechano-immunology under microgravity and different computational modelling approaches that can be used to address the existing problems.
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Affiliation(s)
- Anirudh Murali
- Chemical Engineering and Process Development, CSIR - National Chemical Laboratory, Pune, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Ram Rup Sarkar
- Chemical Engineering and Process Development, CSIR - National Chemical Laboratory, Pune, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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29
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Nguyen J, Chong TW, Elmi H, Ma J, Madi J, Mamgain A, Melendez E, Messina J, Mongia N, Nambiar S, Ng TJ, Nguyen H, McCullough M, Canfora F, O'Reilly LA, Cirillo N, Paolini R, Celentano A. Role of Hemidesmosomes in Oral Carcinogenesis: A Systematic Review. Cancers (Basel) 2023; 15:cancers15092533. [PMID: 37173998 PMCID: PMC10177336 DOI: 10.3390/cancers15092533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Oral cancers have limited diagnostic tools to aid clinical management. Current evidence indicates that alterations in hemidesmosomes, the adhesion complexes primarily involved in epithelial attachment to the basement membrane, are correlated to cancer phenotype for multiple cancers. This systematic review aimed to assess the experimental evidence for hemidesmosomal alterations, specifically in relation to oral potentially malignant disorders and oral squamous cell carcinomas. METHODS We conducted a systemic review to summarise the available literature on hemidesmosomal components and their role in oral pre-cancer and cancer. Relevant studies were retrieved from a comprehensive search of Scopus, Ovid MEDLINE, Ovid Embase and Web of Science. RESULTS 26 articles met the inclusion criteria, of which 19 were in vitro studies, 4 in vivo studies, 1 in vitro and in vivo study, and 2 in vitro and cohort studies. Among them, 15 studies discussed individual alpha-6 and/or beta-4 subunits, 12 studies discussed the alpha-6 beta-4 heterodimers, 6 studies discussed the entire hemidesmosome complex, 5 studies discussed bullous pemphigoid-180, 3 studies discussed plectin, 3 studies discussed bullous pemphigoid antigen-1 and 1 study discussed tetraspanin. CONCLUSION Heterogeneity in cell type, experimental models, and methods were observed. Alterations in hemidesmosomal components were shown to contribute to oral pre-cancer and cancer. We conclude that there is sufficient evidence for hemidesmosomes and their components to be potential biomarkers for evaluating oral carcinogenesis.
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Affiliation(s)
- Jordan Nguyen
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Tze Wei Chong
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Hafsa Elmi
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Jiani Ma
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - John Madi
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Asha Mamgain
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Eileen Melendez
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Julian Messina
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Nikhil Mongia
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Sanjana Nambiar
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Tsu Jie Ng
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Huy Nguyen
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Michael McCullough
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Federica Canfora
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
- Department of Neuroscience, Reproductive Sciences and Dentistry, University of Naples Federico II, 80131 Naples, Italy
| | - Lorraine A O'Reilly
- The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, VIC 3010, Australia
| | - Nicola Cirillo
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Rita Paolini
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
| | - Antonio Celentano
- Melbourne Dental School, The University of Melbourne, 720 Swanston Street, Carlton, VIC 3053, Australia
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30
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Sáez P, Venturini C. Positive, negative and controlled durotaxis. SOFT MATTER 2023; 19:2993-3001. [PMID: 37016959 DOI: 10.1039/d2sm01326f] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Cell migration is a physical process central to life. Among others, it regulates embryogenesis, tissue regeneration, and tumor growth. Therefore, understanding and controlling cell migration represent fundamental challenges in science. Specifically, the ability of cells to follow stiffness gradients, known as durotaxis, is ubiquitous across most cell types. Even so, certain cells follow positive stiffness gradients while others move along negative gradients. How the physical mechanisms involved in cell migration work to enable a wide range of durotactic responses is still poorly understood. Here, we provide a mechanistic rationale for durotaxis by integrating stochastic clutch models for cell adhesion with an active gel theory of cell migration. We show that positive and negative durotaxis found across cell types are explained by asymmetries in the cell adhesion dynamics. We rationalize durotaxis by asymmetric mechanotransduction in the cell adhesion behavior that further polarizes the intracellular retrograde flow and the protruding velocity at the cell membrane. Our theoretical framework confirms previous experimental observations and explains positive and negative durotaxis. Moreover, we show how durotaxis can be engineered to manipulate cell migration, which has important implications in biology, medicine, and bioengineering.
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Affiliation(s)
- P Sáez
- Laboratori de Càlcul Numèric (LaCaN), Universitat Politècnica de Catalunya, Barcelona, Spain.
- E.T.S. de Ingeniería de Caminos, Universitat Politècnica de Catalunya, Barcelona, Spain
- Institut de Matemàtiques de la UPC-BarcelonaTech (IMTech), Universitat Politècnica de Catalunya, Barcelona, Spain
| | - C Venturini
- Laboratori de Càlcul Numèric (LaCaN), Universitat Politècnica de Catalunya, Barcelona, Spain.
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31
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Kastian RF, Baba K, Kaewkascholkul N, Sasaki H, Watanabe R, Toriyama M, Inagaki N. Dephosphorylation of neural wiring protein shootin1 by PP1 phosphatase regulates netrin-1-induced axon guidance. J Biol Chem 2023; 299:104687. [PMID: 37044214 DOI: 10.1016/j.jbc.2023.104687] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/14/2023] Open
Abstract
Axon pathfinding is an essential step in neuronal network formation. Shootin1a is a clutch-linker molecule that is mechanically involved in axon outgrowth and guidance. It was previously shown that concentration gradients of axon guidance molecule netrin-1 in the extracellular environment elicit asymmetrically localized Pak1 kinase-mediated phosphorylation of shootin1a within axonal growth cones, which is higher on the netrin-1 source side. This asymmetric phosphorylation promotes shootin1a-mediated local actin-adhesion coupling within growth cones, thereby generating directional forces for turning the growth cone toward the netrin-1 source. However, how the spatial differences in netrin-1 concentration are transduced into the asymmetrically localized signaling within growth cones remains unclear. Moreover, the protein phosphatases that dephosphorylate shootin1a remain unidentified. Here, we report that protein phosphatase-1 (PP1) dephosphorylates shootin1a in growth cones. We found that PP1 overexpression abolished the netrin-1-induced asymmetric localization of phosphorylated-shootin1a as well as axon turning. In addition, we show PP1 inhibition reversed the asymmetrically localized shootin1a phosphorylation within growth cones under netrin-1 gradient, thereby changing the netrin-1-induced growth cone turning from attraction to repulsion. These data indicate that PP1-mediated shootin1a dephosphorylation plays a key role in organizing asymmetrically-localized phosphorylated shootin1a within growth cones, which regulates netrin-1-induced axon guidance.
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Affiliation(s)
- Ria Fajarwati Kastian
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan; Mammalian Cell Engineering and Signal Transduction Research Group, Research Center for Genetic Engineering, National Research and Innovation Agency, KST Soekarno, Jl. Raya Bogor, KM. 46, Cibinong, Bogor, West Java, 16911, Indonesia
| | - Kentarou Baba
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Napol Kaewkascholkul
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Hisashi Sasaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Rikiya Watanabe
- Molecular Physiology Laboratory, Cluster for Pioneering Research, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Michinori Toriyama
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan.
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32
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Fitz GN, Weck ML, Bodnya C, Perkins OL, Tyska MJ. Protrusion growth driven by myosin-generated force. Dev Cell 2023; 58:18-33.e6. [PMID: 36626869 PMCID: PMC9940483 DOI: 10.1016/j.devcel.2022.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/10/2022] [Accepted: 11/29/2022] [Indexed: 01/11/2023]
Abstract
Actin-based protrusions extend from the surface of all eukaryotic cells, where they support diverse activities essential for life. Models of protrusion growth hypothesize that actin filament assembly exerts force for pushing the plasma membrane outward. However, membrane-associated myosin motors are also abundant in protrusions, although their potential for contributing, growth-promoting force remains unexplored. Using an inducible system that docks myosin motor domains to membrane-binding modules with temporal control, we found that application of myosin-generated force to the membrane is sufficient for driving robust protrusion elongation in human, mouse, and pig cell culture models. Protrusion growth scaled with motor accumulation, required barbed-end-directed force, and was independent of cargo delivery or recruitment of canonical elongation factors. Application of growth-promoting force was also supported by structurally distinct myosin motors and membrane-binding modules. Thus, myosin-generated force can drive protrusion growth, and this mechanism is likely active in diverse biological contexts.
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Affiliation(s)
- Gillian N Fitz
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Meredith L Weck
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Caroline Bodnya
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Olivia L Perkins
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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33
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Reynolds MJ, Hachicho C, Carl AG, Gong R, Alushin GM. Bending forces and nucleotide state jointly regulate F-actin structure. Nature 2022; 611:380-386. [PMID: 36289330 PMCID: PMC9646526 DOI: 10.1038/s41586-022-05366-w] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 09/20/2022] [Indexed: 02/05/2023]
Abstract
ATP-hydrolysis-coupled actin polymerization is a fundamental mechanism of cellular force generation1-3. In turn, force4,5 and actin filament (F-actin) nucleotide state6 regulate actin dynamics by tuning F-actin's engagement of actin-binding proteins through mechanisms that are unclear. Here we show that the nucleotide state of actin modulates F-actin structural transitions evoked by bending forces. Cryo-electron microscopy structures of ADP-F-actin and ADP-Pi-F-actin with sufficient resolution to visualize bound solvent reveal intersubunit interfaces bridged by water molecules that could mediate filament lattice flexibility. Despite extensive ordered solvent differences in the nucleotide cleft, these structures feature nearly identical lattices and essentially indistinguishable protein backbone conformations that are unlikely to be discriminable by actin-binding proteins. We next introduce a machine-learning-enabled pipeline for reconstructing bent filaments, enabling us to visualize both continuous structural variability and side-chain-level detail. Bent F-actin structures reveal rearrangements at intersubunit interfaces characterized by substantial alterations of helical twist and deformations in individual protomers, transitions that are distinct in ADP-F-actin and ADP-Pi-F-actin. This suggests that phosphate rigidifies actin subunits to alter the bending structural landscape of F-actin. As bending forces evoke nucleotide-state dependent conformational transitions of sufficient magnitude to be detected by actin-binding proteins, we propose that actin nucleotide state can serve as a co-regulator of F-actin mechanical regulation.
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Affiliation(s)
- Matthew J Reynolds
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY, USA
| | - Carla Hachicho
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY, USA
| | - Ayala G Carl
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY, USA
- Tri-Institutional Program in Chemical Biology, The Rockefeller University, New York, NY, USA
| | - Rui Gong
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY, USA
| | - Gregory M Alushin
- Laboratory of Structural Biophysics and Mechanobiology, The Rockefeller University, New York, NY, USA.
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34
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Choudhury MI, Benson MA, Sun SX. Trans-epithelial fluid flow and mechanics of epithelial morphogenesis. Semin Cell Dev Biol 2022; 131:146-159. [PMID: 35659163 DOI: 10.1016/j.semcdb.2022.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/14/2022]
Abstract
Active fluid transport across epithelial monolayers is emerging as a major driving force of tissue morphogenesis in a variety of healthy and diseased systems, as well as during embryonic development. Cells use directional transport of ions and osmotic gradients to drive fluid flow across the cell surface, in the process also building up fluid pressure. The basic physics of this process is described by the osmotic engine model, which also underlies actin-independent cell migration. Recently, the trans-epithelial fluid flux and the hydraulic pressure gradient have been explicitly measured for a variety of cellular and tissue model systems across various species. For the kidney, it was shown that tubular epithelial cells behave as active mechanical fluid pumps: the trans-epithelial fluid flux depends on the hydraulic pressure difference across the epithelial layer. When a stall pressure is reached, the fluid flux vanishes. Hydraulic forces generated from active fluid pumping are important in tissue morphogenesis and homeostasis, and could also underlie multiple morphogenic events seen in other developmental contexts. In this review, we highlight findings that examined the role of trans-epithelial fluid flux and hydraulic pressure gradient in driving tissue-scale morphogenesis. We also review organ pathophysiology due to impaired fluid pumping and the loss of hydraulic pressure sensing at the cellular scale. Finally, we draw an analogy between cellular fluidic pumps and a connected network of water pumps in a city. The dynamics of fluid transport in an active and adaptive network is determined globally at the systemic level, and transport in such a network is best when each pump is operating at its optimal efficiency.
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Affiliation(s)
- Mohammad Ikbal Choudhury
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States; Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, United States
| | - Morgan A Benson
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States
| | - Sean X Sun
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States; Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD 21218, United States; Center for Cell Dynamics, Johns Hopkins University, Baltimore, MD 21218, United States.
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35
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Knapp BD, Ward MD, Bowman GR, Shi H, Huang KC. Multiple conserved states characterize the twist landscape of the bacterial actin homolog MreB. Comput Struct Biotechnol J 2022; 20:5838-5846. [PMID: 36382191 PMCID: PMC9627593 DOI: 10.1016/j.csbj.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 12/01/2022] Open
Abstract
Filament formation by cytoskeletal proteins is critical to their involvement in myriad cellular processes. The bacterial actin homolog MreB, which is essential for cell-shape determination in many rod-shaped bacteria, has served as a model system for studying the mechanics of cytoskeletal filaments. Previous molecular dynamics (MD) simulations revealed that the twist of MreB double protofilaments is dependent on the bound nucleotide, as well as binding to the membrane or the accessory protein RodZ, and MreB mutations that modulate twist also affect MreB spatial organization and cell shape. Here, we show that MreB double protofilaments can adopt multiple twist states during microsecond-scale MD simulations. A deep learning algorithm trained only on high- and low-twist states robustly identified all twist conformations across most perturbations of ATP-bound MreB, suggesting the existence of a conserved set of states whose occupancy is affected by each perturbation to MreB. Simulations replacing ATP with ADP indicated that twist states were generally stable after hydrolysis. These findings suggest a rich twist landscape that could provide the capacity to tune MreB activity and therefore its effects on cell shape.
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Affiliation(s)
| | - Michael D. Ward
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gregory R. Bowman
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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36
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Mogilner A, Miles CE. Mechanosensation: Capping actin filaments for robustness. Curr Biol 2022; 32:R1033-R1035. [DOI: 10.1016/j.cub.2022.09.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Chandrasekaran A, Clarke A, McQueen P, Fang HY, Papoian GA, Giniger E. Computational simulations reveal that Abl activity controls cohesiveness of actin networks in growth cones. Mol Biol Cell 2022; 33:ar92. [PMID: 35857718 PMCID: PMC9582807 DOI: 10.1091/mbc.e21-11-0535] [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: 11/01/2021] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 11/11/2022] Open
Abstract
Extensive studies of growing axons have revealed many individual components and protein interactions that guide neuronal morphogenesis. Despite this, however, we lack any clear picture of the emergent mechanism by which this nanometer-scale biochemistry generates the multimicron-scale morphology and cell biology of axon growth and guidance in vivo. To address this, we studied the downstream effects of the Abl signaling pathway using a computer simulation software (MEDYAN) that accounts for mechanochemical dynamics of active polymers. Previous studies implicate two Abl effectors, Arp2/3 and Enabled, in Abl-dependent axon guidance decisions. We now find that Abl alters actin architecture primarily by activating Arp2/3, while Enabled plays a more limited role. Our simulations show that simulations mimicking modest levels of Abl activity bear striking similarity to actin profiles obtained experimentally from live imaging of actin in wild-type axons in vivo. Using a graph theoretical filament-filament contact analysis, moreover, we find that networks mimicking hyperactivity of Abl (enhanced Arp2/3) are fragmented into smaller domains of actin that interact weakly with each other, consistent with the pattern of actin fragmentation observed upon Abl overexpression in vivo. Two perturbative simulations further confirm that high-Arp2/3 actin networks are mechanically disconnected and fail to mount a cohesive response to perturbation. Taken together, these data provide a molecular-level picture of how the large-scale organization of the axonal cytoskeleton arises from the biophysics of actin networks.
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Affiliation(s)
- Aravind Chandrasekaran
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
| | - Akanni Clarke
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
- Department of Biochemistry and Molecular Medicine, George Washington University School of Medicine/National Institutes of Health Graduate Partnerships Program, Washington, DC 20037
| | - Philip McQueen
- Center for Information Technology, National Institutes of Health, Bethesda, MD 20892
| | - Hsiao Yu Fang
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
| | - Garegin A. Papoian
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742
- Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742
| | - Edward Giniger
- National Institute of Neurological Diseases and Stroke, Bethesda, MD 20892
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38
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Francis EA, Heinrich V. Integrative experimental/computational approach establishes active cellular protrusion as the primary driving force of phagocytic spreading by immune cells. PLoS Comput Biol 2022; 18:e1009937. [PMID: 36026476 PMCID: PMC9455874 DOI: 10.1371/journal.pcbi.1009937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 09/08/2022] [Accepted: 07/27/2022] [Indexed: 12/02/2022] Open
Abstract
The dynamic interplay between cell adhesion and protrusion is a critical determinant of many forms of cell motility. When modeling cell spreading on adhesive surfaces, traditional mathematical treatments often consider passive cell adhesion as the primary, if not exclusive, mechanistic driving force of this cellular motion. To better assess the contribution of active cytoskeletal protrusion to immune-cell spreading during phagocytosis, we here develop a computational framework that allows us to optionally investigate both purely adhesive spreading ("Brownian zipper hypothesis") as well as protrusion-dominated spreading ("protrusive zipper hypothesis"). We model the cell as an axisymmetric body of highly viscous fluid surrounded by a cortex with uniform surface tension and incorporate as potential driving forces of cell spreading an attractive stress due to receptor-ligand binding and an outward normal stress representing cytoskeletal protrusion, both acting on the cell boundary. We leverage various model predictions against the results of a directly related experimental companion study of human neutrophil phagocytic spreading on substrates coated with different densities of antibodies. We find that the concept of adhesion-driven spreading is incompatible with experimental results such as the independence of the cell-spreading speed on the density of immobilized antibodies. In contrast, the protrusive zipper model agrees well with experimental findings and, when adapted to simulate cell spreading on discrete adhesion sites, it also reproduces the observed positive correlation between antibody density and maximum cell-substrate contact area. Together, our integrative experimental/computational approach shows that phagocytic spreading is driven by cellular protrusion, and that the extent of spreading is limited by the density of adhesion sites.
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Affiliation(s)
- Emmet A. Francis
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
| | - Volkmar Heinrich
- Department of Biomedical Engineering, University of California Davis, Davis, California, United States of America
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39
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Modeling ATP-mediated endothelial cell elongation on line patterns. Biomech Model Mechanobiol 2022; 21:1531-1548. [PMID: 35902488 PMCID: PMC9626447 DOI: 10.1007/s10237-022-01604-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 06/24/2022] [Indexed: 11/08/2022]
Abstract
Endothelial cell (EC) migration is crucial for a wide range of processes including vascular wound healing, tumor angiogenesis, and the development of viable endovascular implants. We have previously demonstrated that ECs cultured on 15-μm wide adhesive line patterns exhibit three distinct migration phenotypes: (a) “running” cells that are polarized and migrate continuously and persistently on the adhesive lines with possible spontaneous directional changes, (b) “undecided” cells that are highly elongated and exhibit periodic changes in the direction of their polarization while maintaining minimal net migration, and (c) “tumbling-like” cells that migrate persistently for a certain amount of time but then stop and round up for a few hours before spreading again and resuming migration. Importantly, the three migration patterns are associated with distinct profiles of cell length. Because of the impact of adenosine triphosphate (ATP) on cytoskeletal organization and cell polarization, we hypothesize that the observed differences in EC length among the three different migration phenotypes are driven by differences in intracellular ATP levels. In the present work, we develop a mathematical model that incorporates the interactions between cell length, cytoskeletal (F-actin) organization, and intracellular ATP concentration. An optimization procedure is used to obtain the model parameter values that best fit the experimental data on EC lengths. The results indicate that a minimalist model based on differences in intracellular ATP levels is capable of capturing the different cell length profiles observed experimentally.
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Jasnin M, Hervy J, Balor S, Bouissou A, Proag A, Voituriez R, Schneider J, Mangeat T, Maridonneau-Parini I, Baumeister W, Dmitrieff S, Poincloux R. Elasticity of podosome actin networks produces nanonewton protrusive forces. Nat Commun 2022; 13:3842. [PMID: 35789161 PMCID: PMC9253342 DOI: 10.1038/s41467-022-30652-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 05/10/2022] [Indexed: 11/26/2022] Open
Abstract
Actin filaments assemble into force-generating systems involved in diverse cellular functions, including cell motility, adhesion, contractility and division. It remains unclear how networks of actin filaments, which individually generate piconewton forces, can produce forces reaching tens of nanonewtons. Here we use in situ cryo-electron tomography to unveil how the nanoscale architecture of macrophage podosomes enables basal membrane protrusion. We show that the sum of the actin polymerization forces at the membrane is not sufficient to explain podosome protrusive forces. Quantitative analysis of podosome organization demonstrates that the core is composed of a dense network of bent actin filaments storing elastic energy. Theoretical modelling of the network as a spring-loaded elastic material reveals that it exerts forces of a few tens of nanonewtons, in a range similar to that evaluated experimentally. Thus, taking into account not only the interface with the membrane but also the bulk of the network, is crucial to understand force generation by actin machineries. Our integrative approach sheds light on the elastic behavior of dense actin networks and opens new avenues to understand force production inside cells.
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Affiliation(s)
- Marion Jasnin
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
| | - Jordan Hervy
- Université de Paris, CNRS, Institut Jacques Monod, Paris, France
| | - Stéphanie Balor
- Plateforme de Microscopie Électronique Intégrative, Centre de Biologie Intégrative, CNRS, UPS, Toulouse, France
| | - Anaïs Bouissou
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Amsha Proag
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | | | - Jonathan Schneider
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thomas Mangeat
- LITC Core Facility, Centre de Biologie Integrative, Université de Toulouse, CNRS, UPS, 31062, Toulouse, France
| | | | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Serge Dmitrieff
- Université de Paris, CNRS, Institut Jacques Monod, Paris, France.
| | - Renaud Poincloux
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France.
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41
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Lyu B, Chen J, Lou S, Li C, Qiu L, Ouyang W, Xie J, Mitchell I, Wu T, Deng A, Hu C, Zhou X, Shen P, Ma S, Wu Z, Watanabe K, Taniguchi T, Wang X, Liang Q, Jia J, Urbakh M, Hod O, Ding F, Wang S, Shi Z. Catalytic Growth of Ultralong Graphene Nanoribbons on Insulating Substrates. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2200956. [PMID: 35560711 DOI: 10.1002/adma.202200956] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/18/2022] [Indexed: 06/15/2023]
Abstract
Graphene nanoribbons (GNRs) with widths of a few nanometers are promising candidates for future nanoelectronic applications due to their structurally tunable bandgaps, ultrahigh carrier mobilities, and exceptional stability. However, the direct growth of micrometer-long GNRs on insulating substrates, which is essential for the fabrication of nanoelectronic devices, remains an immense challenge. Here, the epitaxial growth of GNRs on an insulating hexagonal boron nitride (h-BN) substrate through nanoparticle-catalyzed chemical vapor deposition is reported. Ultranarrow GNRs with lengths of up to 10 µm are synthesized. Remarkably, the as-grown GNRs are crystallographically aligned with the h-BN substrate, forming 1D moiré superlattices. Scanning tunneling microscopy reveals an average width of 2 nm and a typical bandgap of ≈1 eV for similar GNRs grown on conducting graphite substrates. Fully atomistic computational simulations support the experimental results and reveal a competition between the formation of GNRs and carbon nanotubes during the nucleation stage, and van der Waals sliding of the GNRs on the h-BN substrate throughout the growth stage. This study provides a scalable, single-step method for growing micrometer-long narrow GNRs on insulating substrates, thus opening a route to explore the performance of high-quality GNR devices and the fundamental physics of 1D moiré superlattices.
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Affiliation(s)
- Bosai Lyu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Jiajun Chen
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Shuo Lou
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Can Li
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Lu Qiu
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Wengen Ouyang
- Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan, Hubei, 430072, China
| | - Jingxu Xie
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Izaac Mitchell
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Tongyao Wu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Aolin Deng
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Cheng Hu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Xianliang Zhou
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Peiyue Shen
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Saiqun Ma
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Zhenghan Wu
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Kenji Watanabe
- Research Centre for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Centre for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Xiaoqun Wang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Qi Liang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jinfeng Jia
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Michael Urbakh
- Department of Physical Chemistry, School of Chemistry and The Sackler Centre for Computational Molecular and Materials Science, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Oded Hod
- Department of Physical Chemistry, School of Chemistry and The Sackler Centre for Computational Molecular and Materials Science, The Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Feng Ding
- Centre for Multidimensional Carbon Materials, Institute for Basic Science, Ulsan, 44919, South Korea
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan, 44919, South Korea
| | - Shiyong Wang
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Zhiwen Shi
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, 200240, China
- Collaborative Innovation Centre of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
- Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai, 200240, China
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42
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Xu Q, Li S, Qi M, Gao J, Chen C, Huang P, Wang Y, Yu C, Huang W, Zhou Y. Membrane‐Bound Inward‐Growth of Artificial Cytoskeletons and Their Selective Disassembly. Angew Chem Int Ed Engl 2022; 61:e202204440. [DOI: 10.1002/anie.202204440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Qingsong Xu
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Shanlong Li
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Meiwei Qi
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Jing Gao
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Chuanshuang Chen
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Pei Huang
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Yuling Wang
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Chunyang Yu
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Wei Huang
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
| | - Yongfeng Zhou
- School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China
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43
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Li TD, Bieling P, Weichsel J, Mullins RD, Fletcher DA. The molecular mechanism of load adaptation by branched actin networks. eLife 2022; 11:e73145. [PMID: 35748355 PMCID: PMC9328761 DOI: 10.7554/elife.73145] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 06/07/2022] [Indexed: 11/13/2022] Open
Abstract
Branched actin networks are self-assembling molecular motors that move biological membranes and drive many important cellular processes, including phagocytosis, endocytosis, and pseudopod protrusion. When confronted with opposing forces, the growth rate of these networks slows and their density increases, but the stoichiometry of key components does not change. The molecular mechanisms governing this force response are not well understood, so we used single-molecule imaging and AFM cantilever deflection to measure how applied forces affect each step in branched actin network assembly. Although load forces are observed to increase the density of growing filaments, we find that they actually decrease the rate of filament nucleation due to inhibitory interactions between actin filament ends and nucleation promoting factors. The force-induced increase in network density turns out to result from an exponential drop in the rate constant that governs filament capping. The force dependence of filament capping matches that of filament elongation and can be explained by expanding Brownian Ratchet theory to cover both processes. We tested a key prediction of this expanded theory by measuring the force-dependent activity of engineered capping protein variants and found that increasing the size of the capping protein increases its sensitivity to applied forces. In summary, we find that Brownian Ratchets underlie not only the ability of growing actin filaments to generate force but also the ability of branched actin networks to adapt their architecture to changing loads.
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Affiliation(s)
- Tai-De Li
- Department of Bioengineering & Biophysics Program, University of California, BerkeleyBerkeleyUnited States
- Division of Biological Systems & Engineering, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Advanced Science Research Center, City University of New YorkNew YorkUnited States
| | - Peter Bieling
- Division of Biological Systems & Engineering, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Department of Cellular and Molecular Pharmacology and Howard Hughes Medical Institute, University of California, San FranciscoSan FranciscoUnited States
- Department of Systemic Cell Biology, Max Planck Institute of Molecular PhysiologyDortmundGermany
| | - Julian Weichsel
- Department of Chemistry, University of California, BerkeleyBerkeleyUnited States
| | - R Dyche Mullins
- Department of Cellular and Molecular Pharmacology and Howard Hughes Medical Institute, University of California, San FranciscoSan FranciscoUnited States
| | - Daniel A Fletcher
- Department of Bioengineering & Biophysics Program, University of California, BerkeleyBerkeleyUnited States
- Division of Biological Systems & Engineering, Lawrence Berkeley National LaboratoryBerkeleyUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
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44
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Noh J, Isogai T, Chi J, Bhatt K, Danuser G. Granger-causal inference of the lamellipodial actin regulator hierarchy by live cell imaging without perturbation. Cell Syst 2022; 13:471-487.e8. [PMID: 35675823 DOI: 10.1016/j.cels.2022.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 02/08/2022] [Accepted: 05/10/2022] [Indexed: 11/03/2022]
Abstract
Many cell regulatory systems implicate nonlinearity and redundancy among components. The regulatory network governing lamellipodial and lamellar actin structures is prototypical of such a system, containing tens of actin-nucleating and -modulating molecules with functional overlap and feedback loops. Due to instantaneous and long-term compensation, phenotyping the system response to perturbation provides limited information on the roles the targeted component plays in the unperturbed system. Accordingly, how individual actin regulators contribute to lamellipodial dynamics remains ambiguous. Here, we present a perturbation-free reconstruction of cause-effect relations among actin regulators by applying Granger-causal inference to constitutive image fluctuations that indicate regulator recruitment as a proxy for activity. Our analysis identifies distinct zones of actin regulator activation and of causal effects on filament assembly and delineates actin-dependent and actin-independent regulator roles in controlling edge motion. We propose that edge motion is driven by assembly of two independently operating actin filament systems.
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Affiliation(s)
- Jungsik Noh
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Tadamoto Isogai
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Joseph Chi
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kushal Bhatt
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gaudenz Danuser
- Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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45
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Mechanical Forces Govern Interactions of Host Cells with Intracellular Bacterial Pathogens. Microbiol Mol Biol Rev 2022; 86:e0009420. [PMID: 35285720 PMCID: PMC9199418 DOI: 10.1128/mmbr.00094-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To combat infectious diseases, it is important to understand how host cells interact with bacterial pathogens. Signals conveyed from pathogen to host, and vice versa, may be either chemical or mechanical. While the molecular and biochemical basis of host-pathogen interactions has been extensively explored, relatively less is known about mechanical signals and responses in the context of those interactions. Nevertheless, a wide variety of bacterial pathogens appear to have developed mechanisms to alter the cellular biomechanics of their hosts in order to promote their survival and dissemination, and in turn many host responses to infection rely on mechanical alterations in host cells and tissues to limit the spread of infection. In this review, we present recent findings on how mechanical forces generated by host cells can promote or obstruct the dissemination of intracellular bacterial pathogens. In addition, we discuss how in vivo extracellular mechanical signals influence interactions between host cells and intracellular bacterial pathogens. Examples of such signals include shear stresses caused by fluid flow over the surface of cells and variable stiffness of the extracellular matrix on which cells are anchored. We highlight bioengineering-inspired tools and techniques that can be used to measure host cell mechanics during infection. These allow for the interrogation of how mechanical signals can modulate infection alongside biochemical signals. We hope that this review will inspire the microbiology community to embrace those tools in future studies so that host cell biomechanics can be more readily explored in the context of infection studies.
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46
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Seifert J, Rheinlaender J, von Eysmondt H, Schäffer TE. Mechanics of migrating platelets investigated with scanning ion conductance microscopy. NANOSCALE 2022; 14:8192-8199. [PMID: 35621412 DOI: 10.1039/d2nr01187e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Platelets are small blood cells involved in hemostasis, wound healing, and immune response. After adhesion and spreading, platelets can migrate at sites of injury inducing an early immune response to inflammation or infection. Platelet migration requires fibrinogen-integrin binding and fibrinogen depletion from the substrate inducing a self-generated ligand gradient guiding the direction of migration. This type of cellular motion is referred to as haptotactic migration. The underlying mechanisms of haptotactic platelet migration have just recently been discovered, but the connection to platelet mechanics has remained unknown yet. Using scanning ion conductance microscopy (SICM), we investigated the three-dimensional morphology and mechanics of platelets during haptotactic migration for the first time. Migrating platelets showed a polarized, anisotropic shape oriented in the direction of migration. This polarization goes hand in hand with a characteristic subcellular stiffness distribution showing a region of increased stiffness at the leading edge. Moreover, the mechanical properties of the leading edge revealed a highly dynamic stiffening and softening process with rapid changes of the elastic modulus by a factor of up to 5× per minute. Inhibition of actin polymerization stopped the dynamic stiffening and softening process and halted the migration. By combining SICM with confocal fluorescence microscopy, we found that the increased stiffness and mechanical dynamics at the leading edge coincided with an increased volumetric F-actin density. Our data provide a connection between platelet mechanics and the cytoskeletal contribution to the migration process of platelets.
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Affiliation(s)
- Jan Seifert
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Johannes Rheinlaender
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Hendrik von Eysmondt
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
| | - Tilman E Schäffer
- Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany.
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47
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Structure of Arp2/3 complex at a branched actin filament junction resolved by single-particle cryo-electron microscopy. Proc Natl Acad Sci U S A 2022; 119:e2202723119. [PMID: 35622886 DOI: 10.1073/pnas.2202723119] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
SignificanceActin filament nucleation by Arp2/3 complex must be triggered by activators like WASP family proteins. Understanding how WASP proteins activate Arp2/3 complex has been a major challenge due to a lack of high-resolution structures of the complex in an activated state. We determined a high-resolution (∼3.9 Å) structure of the WASP-activated Arp2/3 complex at a branch junction and used biochemical, cell biological, and molecular dynamic simulations to understand the mechanism of WASP-mediated activation. This work shows in detail the contacts between the fully activated Arp2/3 complex, the nucleated daughter actin filament, and the mother actin filament and provides important insights into how conformational rearrangements in the Arp2/3 complex are stimulated during activation.
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48
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Banerjee DS, Banerjee S. Emergence and maintenance of variable-length actin filaments in a limiting pool of building blocks. Biophys J 2022; 121:2436-2448. [PMID: 35598045 DOI: 10.1016/j.bpj.2022.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 04/10/2022] [Accepted: 05/13/2022] [Indexed: 11/16/2022] Open
Abstract
Actin is one of the key structural components of the eukaryotic cytoskeleton that regulates cellular architecture and mechanical properties. Dynamic regulation of actin filament length and organization is essential for the control of many physiological processes including cell adhesion, motility and division. While previous studies have mostly focused on the mechanisms controlling the mean length of individual actin filaments, it remains poorly understood how distinct actin filament populations in cells maintain different lengths using the same set of molecular building blocks. Here we develop a theoretical model for the length regulation of multiple actin filaments by nucleation and growth rate modulation by actin binding proteins in a limiting pool of monomers. We first show that spontaneous nucleation of actin filaments naturally leads to heterogeneities in filament length distribution. We then investigate the effects of filament growth inhibition by capping proteins and growth promotion by formin proteins on filament length distribution. We find that filament length heterogeneity can be increased by growth inhibition, whereas growth promoters do not significantly affect length heterogeneity. Interestingly, a competition between filament growth inhibitors and growth promoters can give rise to bimodal filament length distribution as well as a highly heterogeneous length distribution with large statistical dispersion. We quantitatively predict how heterogeneity in actin filament length can be modulated by tuning F-actin nucleation and growth rates in order to create distinct filament subpopulations with different lengths. SIGNIFICANCE: Actin filaments organize into different functional network architectures within eukaryotic cells. To maintain distinct actin network architectures, it is essential to regulate the lengths of actin filaments. While the mechanisms controlling the lengths of individual actin filaments have been extensively studied, the regulation of length heterogeneity in actin filament populations is not well understood. Here we show that the modulation of actin filament growth and nucleation rates by actin binding proteins can regulate actin length distribution and create distinct sub-populations with different lengths. In particular, by tuning concentrations of formin, profilin and capping proteins, various aspects of actin filament length distribution can be controlled. Insights gained from our results may have significant implications for the regulation of actin filament length heterogeneity and architecture within a cell.
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Affiliation(s)
- Deb Sankar Banerjee
- Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213, USA
| | - Shiladitya Banerjee
- Carnegie Mellon University, Department of Physics, Pittsburgh, PA 15213, USA
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49
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Yao L, Li Y. Effective Force Generation During Mammalian Cell Migration Under Different Molecular and Physical Mechanisms. Front Cell Dev Biol 2022; 10:903234. [PMID: 35663404 PMCID: PMC9160717 DOI: 10.3389/fcell.2022.903234] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 05/02/2022] [Indexed: 11/23/2022] Open
Abstract
We have developed much understanding of actin-driven cell migration and the forces that propel cell motility. However, fewer studies focused on estimating the effective forces generated by migrating cells. Since cells in vivo are exposed to complex physical environments with various barriers, understanding the forces generated by cells will provide insights into how cells manage to navigate challenging environments. In this work, we use theoretical models to discuss actin-driven and water-driven cell migration and the effect of cell shapes on force generation. The results show that the effective force generated by actin-driven cell migration is proportional to the rate of actin polymerization and the strength of focal adhesion; the energy source comes from the actin polymerization against the actin network pressure. The effective force generated by water-driven cell migration is proportional to the rate of active solute flux and the coefficient of external hydraulic resistance; the energy sources come from active solute pumping against the solute concentration gradient. The model further predicts that the actin network distribution is mechanosensitive and the presence of globular actin helps to establish a biphasic cell velocity in the strength of focal adhesion. The cell velocity and effective force generation also depend on the cell shape through the intracellular actin flow field.
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Affiliation(s)
- Lingxing Yao
- Department of Mathematics, University of Akron, Akron, OH, United States
| | - Yizeng Li
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, United States
- *Correspondence: Yizeng Li,
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Ariga K. Mechano-Nanoarchitectonics: Design and Function. SMALL METHODS 2022; 6:e2101577. [PMID: 35352500 DOI: 10.1002/smtd.202101577] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 03/12/2022] [Indexed: 05/27/2023]
Abstract
Mechanical stimuli have rather ambiguous and less-specific features among various physical stimuli, but most materials exhibit a certain level of responses upon mechanical inputs. Unexplored sciences remain in mechanical responding systems as one of the frontiers of materials science. Nanoarchitectonics approaches for mechanically responding materials are discussed as mechano-nanoarchitectonics in this review article. Recent approaches on molecular and materials systems with mechanical response capabilities are first exemplified with two viewpoints: i) mechanical control of supramolecular assemblies and materials and ii) mechanical control and evaluation of atom/molecular level structures. In the following sections, special attentions on interfacial environments for mechano-nanoarchitectonics are emphasized. The section entitled iii) Mechanical Control of Molecular System at Dynamic Interface describes coupling of macroscopic mechanical forces and molecular-level phenomena. Delicate mechanical forces can be applied to functional molecules embedded at the air-water interface where operation of molecular machines and tuning of molecular receptors upon macroscopic mechanical actions are discussed. Finally, the important role of the interfacial media are further extended to the control of living cells as described in the section entitled iv) Mechanical Control of Biosystems. Pioneering approaches on cell fate regulations at liquid-liquid interfaces are discussed in addition to well-known mechanobiology.
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Affiliation(s)
- Katsuhiko Ariga
- World Premier International (WPI) Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, 305-0044, Japan
- Department of Advanced Materials Science, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561, Japan
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