1
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Beta C, Edelstein-Keshet L, Gov N, Yochelis A. From actin waves to mechanism and back: How theory aids biological understanding. eLife 2023; 12:e87181. [PMID: 37428017 DOI: 10.7554/elife.87181] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/01/2023] [Indexed: 07/11/2023] Open
Abstract
Actin dynamics in cell motility, division, and phagocytosis is regulated by complex factors with multiple feedback loops, often leading to emergent dynamic patterns in the form of propagating waves of actin polymerization activity that are poorly understood. Many in the actin wave community have attempted to discern the underlying mechanisms using experiments and/or mathematical models and theory. Here, we survey methods and hypotheses for actin waves based on signaling networks, mechano-chemical effects, and transport characteristics, with examples drawn from Dictyostelium discoideum, human neutrophils, Caenorhabditis elegans, and Xenopus laevis oocytes. While experimentalists focus on the details of molecular components, theorists pose a central question of universality: Are there generic, model-independent, underlying principles, or just boundless cell-specific details? We argue that mathematical methods are equally important for understanding the emergence, evolution, and persistence of actin waves and conclude with a few challenges for future studies.
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Affiliation(s)
- Carsten Beta
- Institute of Physics and Astronomy, University of Potsdam, Potsdam, Germany
| | | | - Nir Gov
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Arik Yochelis
- Swiss Institute for Dryland Environmental and Energy Research, Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, Israel
- Department of Physics, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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2
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Kreider-Letterman G, Cooke M, Goicoechea SM, Kazanietz MG, Garcia-Mata R. Quantification of ruffle area and dynamics in live or fixed lung adenocarcinoma cells. STAR Protoc 2022; 3:101437. [PMID: 35677607 PMCID: PMC9168141 DOI: 10.1016/j.xpro.2022.101437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Ruffles are actin-rich membrane protrusions implicated in actin reorganization and initiation of cell motility. Here, we describe methods for measuring and analyzing ruffle dynamics in live cells and average ruffle area per cell in fixed samples. The specific steps described are for the analysis of A549 lung adenocarcinoma cells, but the protocol can be applied to other cell types. The protocol has applications for dissecting the signaling events linked to ruffling. For complete details on the use and execution of this protocol, please refer to Cooke et al. (2021).
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Affiliation(s)
| | - Mariana Cooke
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Medicine, Einstein Medical Center Philadelphia, Philadelphia, PA 19141, USA
| | | | - Marcelo G. Kazanietz
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rafael Garcia-Mata
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
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3
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Ranadewa D, Wu J, Subramanianbalachandar VA, Steward RL. Variable fluid flow regimes alter human brain microvascular endothelial cell-cell junctions and cytoskeletal structure. Cytoskeleton (Hoboken) 2021; 78:323-334. [PMID: 34467654 DOI: 10.1002/cm.21687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 08/03/2021] [Accepted: 08/23/2021] [Indexed: 12/27/2022]
Abstract
The human brain microvasculature is constantly exposed to variable fluid flow regimes and their influence on the endothelium depends in part on the synchronous cooperative behavior between cell-cell junctions and the cytoskeleton. In this study, we exposed human cerebral microvascular endothelial cells to a low laminar flow (1 dyne⋅cm-2 ), high laminar flow (10 dyne⋅cm-2 ), low oscillatory flow (±1 dyne⋅cm-2 ), or high oscillatory flow (±10 dyne⋅cm-2 ) for 24 hr. After this time, endothelial cell-cell junction and cytoskeletal structural response was characterized through observation of zonula occludens-1 (ZO-1), claudin-5, junctional adhesion molecule-A (JAM-A), vascular endothelial cadherin (VE-Cad), and F-actin. In addition, we also characterized cell morphology through measurement of cell area and cell eccentricity. Our results revealed the greatest change in junctional structure reorganization for ZO-1 and JAM-A to be observed under low laminar flow conditions while claudin-5 exhibited the greatest change in structural reorganization under both low and high laminar flow conditions. However, VE-Cad displayed the greatest structural response under a high laminar flow, reflecting the unique responses each cell-cell junction protein had to each fluid flow regime. In addition, cell area and cell eccentricity displayed most significant changes under the high laminar flow and low oscillatory flow, respectively. We believe this study will be useful to the field of cell mechanics and mechanobiology.
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Affiliation(s)
- Dilshan Ranadewa
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA
| | - Jingwen Wu
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA
| | | | - Robert L Steward
- Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida, USA.,Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida, USA
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4
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Wan L, Neumann CA, LeDuc PR. Tumor-on-a-chip for integrating a 3D tumor microenvironment: chemical and mechanical factors. LAB ON A CHIP 2020; 20:873-888. [PMID: 32025687 PMCID: PMC7067141 DOI: 10.1039/c9lc00550a] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Tumor progression, including metastasis, is significantly influenced by factors in the tumor microenvironment (TME) such as mechanical force, shear stress, chemotaxis, and hypoxia. At present, most cancer studies investigate tumor metastasis by conventional cell culture methods and animal models, which are limited in data interpretation. Although patient tissue analysis, such as human patient-derived xenografts (PDX), can provide important clinical relevant information, they may not be feasible for functional studies as they are costly and time-consuming. Thus, in vitro three-dimensional (3D) models are rapidly being developed that mimic TME and allow functional investigations of metastatic mechanisms and drug responses. One of those new 3D models is tumor-on-a-chip technology that provides a powerful in vitro platform for cancer research, with the ability to mimic the complex physiological architecture and precise spatiotemporal control. Tumor-on-a-chip technology can provide integrated features including 3D scaffolding, multicellular culture, and a vasculature system to simulate dynamic flow in vivo. Here, we review a select set of recent achievements in tumor-on-a-chip approaches and present potential directions for tumor-on-a-chip systems in the future for areas including mechanical and chemical mimetic systems. We also discuss challenges and perspectives in both biological factors and engineering methods for tumor-on-a-chip progress. These approaches will allow in the future for the tumor-on-a-chip systems to test therapeutic approaches for individuals through using their cancerous cells gathered through approaches like biopsies, which then will contribute toward personalized medicine treatments for improving their outcomes.
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Affiliation(s)
- L Wan
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213 US.
| | - C A Neumann
- Department of Pharmacology & Chemical Biology, University of Pittsburgh Medical Center Hillman Cancer Center, Magee Womens Research Institute, 204 Craft Avenue, Pittsburgh, PA, 15213 US.
| | - P R LeDuc
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213 US.
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5
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Zobel M, Disanza A, Senic-Matuglia F, Franco M, Colaluca IN, Confalonieri S, Bisi S, Barbieri E, Caldieri G, Sigismund S, Pece S, Chavrier P, Di Fiore PP, Scita G. A NUMB-EFA6B-ARF6 recycling route controls apically restricted cell protrusions and mesenchymal motility. J Cell Biol 2018; 217:3161-3182. [PMID: 30061108 PMCID: PMC6123001 DOI: 10.1083/jcb.201802023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 05/17/2018] [Accepted: 06/05/2018] [Indexed: 12/13/2022] Open
Abstract
The endocytic protein NUMB has been implicated in the control of various polarized cellular processes, including the acquisition of mesenchymal migratory traits through molecular mechanisms that have only been partially defined. Here, we report that NUMB is a negative regulator of a specialized set of understudied, apically restricted, actin-based protrusions, the circular dorsal ruffles (CDRs), induced by either PDGF or HGF stimulation. Through its PTB domain, NUMB binds directly to an N-terminal NPLF motif of the ARF6 guanine nucleotide exchange factor, EFA6B, and promotes its exchange activity in vitro. In cells, a NUMB-EFA6B-ARF6 axis regulates the recycling of the actin regulatory cargo RAC1 and is critical for the formation of CDRs that mark the acquisition of a mesenchymal mode of motility. Consistently, loss of NUMB promotes HGF-induced cell migration and invasion. Thus, NUMB negatively controls membrane protrusions and the acquisition of mesenchymal migratory traits by modulating EFA6B-ARF6 activity.
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Affiliation(s)
- Martina Zobel
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Andrea Disanza
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | | | - Michel Franco
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | | | | | - Sara Bisi
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
| | - Elisa Barbieri
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Giusi Caldieri
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Sara Sigismund
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Salvatore Pece
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Philippe Chavrier
- Institut Curie, PSL Research University, Paris, France
- Centre National de la Recherche Scientifique UMR 144, Membrane and Cytoskeleton Dynamics Team, Paris, France
| | - Pier Paolo Di Fiore
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Giorgio Scita
- IFOM, the FIRC Institute of Molecular Oncology, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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6
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DePasquale JA. Apical surface ring formation in
Cyprinus carpio
scale epidermis. ACTA ZOOL-STOCKHOLM 2018. [DOI: 10.1111/azo.12256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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7
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A RAB35-p85/PI3K axis controls oscillatory apical protrusions required for efficient chemotactic migration. Nat Commun 2018; 9:1475. [PMID: 29662076 PMCID: PMC5902610 DOI: 10.1038/s41467-018-03571-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 02/15/2018] [Indexed: 11/17/2022] Open
Abstract
How cells move chemotactically remains a major unmet challenge in cell biology. Emerging evidence indicates that for interpreting noisy, shallow gradients of soluble cues a system must behave as an excitable process. Here, through an RNAi-based, high-content screening approach, we identify RAB35 as necessary for the formation of growth factors (GFs)-induced waves of circular dorsal ruffles (CDRs), apically restricted actin-rich migratory protrusions. RAB35 is sufficient to induce recurrent and polarized CDRs that travel as propagating waves, thus behaving as an excitable system that can be biased to control cell steering. Consistently, RAB35 is essential for promoting directed chemotactic migration and chemoinvasion of various cells in response to gradients of motogenic GFs. Molecularly, RAB35 does so by directly regulating the activity of p85/PI3K polarity axis. We propose that RAB35 is a molecular determinant for the control of an excitable, oscillatory system that acts as a steering wheel for GF-mediated chemotaxis and chemoinvasion. Circular dorsal ruffles (CDRs) are apical actin enriched structures involved in the interpretation of growth factor gradients during cell migration. Here, the authors find that a RAB35/PI3K axis is necessary and sufficient for the formation and stabilization of polarized CDRs and persistent directional migration.
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8
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Cheng B, Lin M, Huang G, Li Y, Ji B, Genin GM, Deshpande VS, Lu TJ, Xu F. Energetics: An emerging frontier in cellular mechanosensing. Phys Life Rev 2017; 22-23:130-135. [DOI: 10.1016/j.plrev.2017.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 09/20/2017] [Indexed: 10/25/2022]
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9
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Cheng B, Lin M, Huang G, Li Y, Ji B, Genin GM, Deshpande VS, Lu TJ, Xu F. Cellular mechanosensing of the biophysical microenvironment: A review of mathematical models of biophysical regulation of cell responses. Phys Life Rev 2017; 22-23:88-119. [PMID: 28688729 PMCID: PMC5712490 DOI: 10.1016/j.plrev.2017.06.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 06/14/2017] [Indexed: 12/11/2022]
Abstract
Cells in vivo reside within complex microenvironments composed of both biochemical and biophysical cues. The dynamic feedback between cells and their microenvironments hinges upon biophysical cues that regulate critical cellular behaviors. Understanding this regulation from sensing to reaction to feedback is therefore critical, and a large effort is afoot to identify and mathematically model the fundamental mechanobiological mechanisms underlying this regulation. This review provides a critical perspective on recent progress in mathematical models for the responses of cells to the biophysical cues in their microenvironments, including dynamic strain, osmotic shock, fluid shear stress, mechanical force, matrix rigidity, porosity, and matrix shape. The review highlights key successes and failings of existing models, and discusses future opportunities and challenges in the field.
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Affiliation(s)
- Bo Cheng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Min Lin
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Guoyou Huang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Yuhui Li
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Baohua Ji
- Biomechanics and Biomaterials Laboratory, Department of Applied Mechanics, Beijing Institute of Technology, Beijing, China
| | - Guy M Genin
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China; Department of Mechanical Engineering & Materials Science, and NSF Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis 63130, MO, USA
| | - Vikram S Deshpande
- Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, United Kingdom
| | - Tian Jian Lu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Feng Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710049, PR China; Bioinspired Engineering and Biomechanics Center (BEBC), Xi'an Jiaotong University, Xi'an 710049, PR China.
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10
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Wu J, LeDuc P, Steward R. How can we predict cellular mechanosensation?: Comment on "Cellular mechanosensing of the biophysical microenvironment: A review of mathematical models of biophysical regulation of cell responses" by Bo Cheng et al. Phys Life Rev 2017; 22-23:120-122. [PMID: 28890169 PMCID: PMC5908231 DOI: 10.1016/j.plrev.2017.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 08/27/2017] [Indexed: 10/18/2022]
Affiliation(s)
- Jingwen Wu
- Departments of Mechanical and Aerospace Engineering, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Philip LeDuc
- Departments of Mechanical Engineering, Biomedical Engineering, Computational Biology, and Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States.
| | - Robert Steward
- Departments of Mechanical and Aerospace Engineering, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States.
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11
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Abstract
During macropinocytosis, cells remodel their morphologies for the uptake of extracellular matter. This endocytotic mechanism relies on the collapse and closure of precursory structures, which are propagating actin-based, ring-shaped vertical undulations at the dorsal (top) cell membrane, a.k.a. circular dorsal ruffles (CDRs). As such, CDRs are essential to a range of vital and pathogenic processes alike. Here we show, based on both experimental data and theoretical analysis, that CDRs are propagating fronts of actin polymerization in a bistable system. The theory relies on a novel mass-conserving reaction–diffusion model, which associates the expansion and contraction of waves to distinct counter-propagating front solutions. Moreover, the model predicts that under a change in parameters (for example, biochemical conditions) CDRs may be pinned and fluctuate near the cell boundary or exhibit complex spiral wave dynamics due to a wave instability. We observe both phenomena also in our experiments indicating the conditions for which macropinocytosis is suppressed. Circular dorsal ruffles (CDRs) are important for the vesicular uptake of extracellular matter, but the basis of their wave dynamics is not understood. Here, the authors propose and experimentally test a bistable reaction-diffusion system, which they show accounts for the typical CDR expansion and shrinkage and for aberrant formation of pinned waves and spirals.
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12
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Valdivia A, Goicoechea SM, Awadia S, Zinn A, Garcia-Mata R. Regulation of circular dorsal ruffles, macropinocytosis, and cell migration by RhoG and its exchange factor, Trio. Mol Biol Cell 2017; 28:1768-1781. [PMID: 28468978 PMCID: PMC5491185 DOI: 10.1091/mbc.e16-06-0412] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 11/11/2022] Open
Abstract
The small GTPase RhoG and its exchange factor, Trio, regulate the formation and size of circular dorsal ruffles and associated functions, including macropinocytosis and cell migration. Circular dorsal ruffles (CDRs) are actin-rich structures that form on the dorsal surface of many mammalian cells in response to growth factor stimulation. CDRs represent a unique type of structure that forms transiently and only once upon stimulation. The formation of CDRs involves a drastic rearrangement of the cytoskeleton, which is regulated by the Rho family of GTPases. So far, only Rac1 has been consistently associated with CDR formation, whereas the role of other GTPases in this process is either lacking or inconclusive. Here we show that RhoG and its exchange factor, Trio, play a role in the regulation of CDR dynamics, particularly by modulating their size. RhoG is activated by Trio downstream of PDGF in a PI3K- and Src-dependent manner. Silencing RhoG expression decreases the number of cells that form CDRs, as well as the area of the CDRs. The regulation of CDR area by RhoG is independent of Rac1 function. In addition, our results show the RhoG plays a role in the cellular functions associated with CDR formation, including macropinocytosis, receptor internalization, and cell migration. Taken together, our results reveal a novel role for RhoG in the regulation of CDRs and the cellular processes associated with their formation.
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Affiliation(s)
- Alejandra Valdivia
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606.,Division of Cardiology, School of Medicine, Emory University, Atlanta, GA 30322
| | | | - Sahezeel Awadia
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Ashtyn Zinn
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Rafael Garcia-Mata
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
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13
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Aikawa T, Kudo H, Kondo T, Yuasa M. Surface pattern formation on soft polymer substrate through photo-initiated graft polymerization. POLYM ADVAN TECHNOL 2017. [DOI: 10.1002/pat.4029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Tatsuo Aikawa
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Hiroaki Kudo
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Takeshi Kondo
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
- Research Institute of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
| | - Makoto Yuasa
- Department of Pure and Applied Chemistry, Faculty of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
- Research Institute of Science and Technology; Tokyo University of Science; 2641 Yamazaki Noda Chiba 278-8510 Japan
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14
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Bernitt E, Döbereiner HG. Spatiotemporal Patterns of Noise-Driven Confined Actin Waves in Living Cells. PHYSICAL REVIEW LETTERS 2017; 118:048102. [PMID: 28186815 DOI: 10.1103/physrevlett.118.048102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Indexed: 06/06/2023]
Abstract
Cells utilize waves of polymerizing actin to reshape their morphologies, which is central to physiological and pathological processes alike. Here, we force dorsal actin waves to propagate on one-dimensional domains with periodic boundary conditions, which results in striking spatiotemporal patterns with a clear signature of noise-driven dynamics. We show that these patterns can be very closely reproduced with a noise-driven active medium at coherence resonance.
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Affiliation(s)
- Erik Bernitt
- Institut für Biophysik, Universität Bremen, 28359 Bremen, Germany
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15
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Bordeleau F, Reinhart-King CA. Tuning cell migration: contractility as an integrator of intracellular signals from multiple cues. F1000Res 2016; 5. [PMID: 27508074 PMCID: PMC4962296 DOI: 10.12688/f1000research.7884.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/22/2016] [Indexed: 02/06/2023] Open
Abstract
There has been immense progress in our understanding of the factors driving cell migration in both two-dimensional and three-dimensional microenvironments over the years. However, it is becoming increasingly evident that even though most cells share many of the same signaling molecules, they rarely respond in the same way to migration cues. To add to the complexity, cells are generally exposed to multiple cues simultaneously, in the form of growth factors and/or physical cues from the matrix. Understanding the mechanisms that modulate the intracellular signals triggered by multiple cues remains a challenge. Here, we will focus on the molecular mechanism involved in modulating cell migration, with a specific focus on how cell contractility can mediate the crosstalk between signaling initiated at cell-matrix adhesions and growth factor receptors.
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Affiliation(s)
- Francois Bordeleau
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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16
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Masters TA, Sheetz MP, Gauthier NC. F-actin waves, actin cortex disassembly and focal exocytosis driven by actin-phosphoinositide positive feedback. Cytoskeleton (Hoboken) 2016; 73:180-96. [PMID: 26915738 DOI: 10.1002/cm.21287] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/11/2016] [Accepted: 02/18/2016] [Indexed: 12/29/2022]
Abstract
Actin polymerization is controlled by the phosphoinositide composition of the plasma membrane. However, the molecular mechanisms underlying the spatiotemporal regulation of actin network organization over extended length scales are still unclear. To observe phosphoinositide-dependent cytoskeletal dynamics we combined the model system of frustrated phagocytosis, total internal reflection microscopy and manipulation of the buffer tonicity. We found that macrophages interacting with IgG-coated glass substrates formed circular F-actin waves on their ventral surface enclosing a region of plasma membrane devoid of cortical actin. Plasma membrane free of actin cortex was strongly depleted of PI(4,5)P2 , but enriched in PI(3,4)P2 and displayed a fivefold increase in exocytosis. Wave formation could be promoted by application of a hypotonic shock. The actin waves were characteristic of a bistable wavefront at the boundary between the regions of membrane containing and lacking cortical actin. Phosphoinositide modifiers and RhoGTPase activities dramatically redistributed with respect to the wavefronts, which often exhibited spatial oscillations. Perturbation of either lipid or actin cytoskeleton-related pathways led to rapid loss of both the polarized lipid distribution and the wavefront. As waves travelled over the plasma membrane, wavefront actin was seen to rapidly polymerize and depolymerize at pre-existing clusters of FcγRIIA, coincident with rapid changes in lipid composition. Thus the potential of receptors to support rapid F-actin polymerization appears to depend acutely on the local concentrations of multiple lipid species. We propose that interdependence through positive feedback from the cytoskeleton to lipid modifiers leads to coordinated local cortex remodeling, focal exocytosis, and organizes extended actin networks.
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Affiliation(s)
- Thomas A Masters
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
| | - Michael P Sheetz
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore.,Department of Biological Sciences, Columbia University, New York, New York, 10027
| | - Nils C Gauthier
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore, 117411, Singapore
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17
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Tissue stiffness regulates serine/arginine-rich protein-mediated splicing of the extra domain B-fibronectin isoform in tumors. Proc Natl Acad Sci U S A 2015; 112:8314-9. [PMID: 26106154 DOI: 10.1073/pnas.1505421112] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Alternative splicing of proteins gives rise to different isoforms that play a crucial role in regulating several cellular processes. Notably, splicing profiles are altered in several cancer types, and these profiles are believed to be involved in driving the oncogenic process. Although the importance of alternative splicing alterations occurring during cancer is increasingly appreciated, the underlying regulatory mechanisms remain poorly understood. In this study, we use both biochemical and physical tools coupled with engineered models, patient samples, and a murine model to investigate the role of the mechanical properties of the tumor microenvironment in regulating the production of the extra domain-B (EDB) splice variant of fibronectin (FN), a hallmark of tumor angiogenesis. Specifically, we show that the amount of EDB-FN produced by endothelial cells increases with matrix stiffness both in vitro and within mouse mammary tumors. Matrix stiffness regulates splicing through the activation of serine/arginine rich (SR) proteins, the splicing factors involved in the production of FN isoforms. Activation of the SR proteins by matrix stiffness and the subsequent production of EDB-FN are dependent on intracellular contractility and PI3K-AKT signaling. Notably, matrix stiffness-mediated splicing is not limited to EDB-FN, but also affects splicing in the production of PKC βII and the VEGF 165b splice variant. Together, these results demonstrate that the mechanical properties of the microenvironment regulate alternative splicing and establish a previously unidentified mechanism by which cells can adapt to their microenvironment.
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Modeling large-scale dynamic processes in the cell: polarization, waves, and division. Q Rev Biophys 2015; 47:221-48. [PMID: 25124728 DOI: 10.1017/s0033583514000079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The past decade has witnessed significant developments in molecular biology techniques, fluorescent labeling, and super-resolution microscopy, and together these advances have vastly increased our quantitative understanding of the cell. This detailed knowledge has concomitantly opened the door for biophysical modeling on a cellular scale. There have been comprehensive models produced describing many processes such as motility, transport, gene regulation, and chemotaxis. However, in this review we focus on a specific set of phenomena, namely cell polarization, F-actin waves, and cytokinesis. In each case, we compare and contrast various published models, highlight the relevant aspects of the biology, and provide a sense of the direction in which the field is moving.
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Yochelis A, Knobloch E, Köpf MH. Origin of finite pulse trains: Homoclinic snaking in excitable media. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:032924. [PMID: 25871189 DOI: 10.1103/physreve.91.032924] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Indexed: 06/04/2023]
Abstract
Many physical, chemical, and biological systems exhibit traveling waves as a result of either an oscillatory instability or excitability. In the latter case a large multiplicity of stable spatially localized wavetrains consisting of different numbers of traveling pulses may be present. The existence of these states is related here to the presence of homoclinic snaking in the vicinity of a subcritical, finite wavenumber Hopf bifurcation. The pulses are organized in a slanted snaking structure resulting from the presence of a heteroclinic cycle between small and large amplitude traveling waves. Connections of this type require a multivalued dispersion relation. This dispersion relation is computed numerically and used to interpret the profile of the pulse group. The different spatially localized pulse trains can be accessed by appropriately customized initial stimuli, thereby blurring the traditional distinction between oscillatory and excitable systems. The results reveal a new class of phenomena relevant to spatiotemporal dynamics of excitable media, particularly in chemical and biological systems with multiple activators and inhibitors.
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Affiliation(s)
- Arik Yochelis
- Department of Solar Energy and Environmental Physics, Swiss Institute for Dryland Environmental and Energy Research, Jacob Blaustein Institutes for Desert Research (BIDR), Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion 84990, Israel
| | - Edgar Knobloch
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Michael H Köpf
- Département de Physique, École Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
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Dynamics of actin waves on patterned substrates: a quantitative analysis of circular dorsal ruffles. PLoS One 2015; 10:e0115857. [PMID: 25574668 PMCID: PMC4289068 DOI: 10.1371/journal.pone.0115857] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 11/28/2014] [Indexed: 11/19/2022] Open
Abstract
Circular Dorsal Ruffles (CDRs) have been known for decades, but the mechanism that organizes these actin waves remains unclear. In this article we systematically analyze the dynamics of CDRs on fibroblasts with respect to characteristics of current models of actin waves. We studied CDRs on heterogeneously shaped cells and on cells that we forced into disk-like morphology. We show that CDRs exhibit phenomena such as periodic cycles of formation, spiral patterns, and mutual wave annihilations that are in accord with an active medium description of CDRs. On cells of controlled morphologies, CDRs exhibit extremely regular patterns of repeated wave formation and propagation, whereas on random-shaped cells the dynamics seem to be dominated by the limited availability of a reactive species. We show that theoretical models of reaction-diffusion type incorporating conserved species capture partially the behavior we observe in our data.
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Ronan W, Deshpande VS, McMeeking RM, McGarry JP. Cellular contractility and substrate elasticity: a numerical investigation of the actin cytoskeleton and cell adhesion. Biomech Model Mechanobiol 2013; 13:417-35. [DOI: 10.1007/s10237-013-0506-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 06/01/2013] [Indexed: 01/08/2023]
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Huynh J, Bordeleau F, Kraning-Rush CM, Reinhart-King CA. Substrate Stiffness Regulates PDGF-Induced Circular Dorsal Ruffle Formation Through MLCK. Cell Mol Bioeng 2013; 6. [PMID: 24348877 DOI: 10.1007/s12195-013-0278-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
As atherosclerosis progresses, vascular smooth muscle cells (VSMCs) invade from the medial layer into the intimal layer and proliferate, contributing to atherosclerotic plaque formation. This migration is stimulated in part by platelet-derived growth factor (PDGF), which is released by endothelial cells and inflammatory cells, and vessel stiffening, which occurs with age and atherosclerosis progression. PDGF induces the formation of circular dorsal ruffles (CDRs), actin-based structures associated with increased cell motility. Here we show that mechanical changes in matrix stiffness enhance the formation of CDRs in VSMCs in response to PDGF stimulation. Our data indicate that matrix stiffness increases cellular contractility, and that intracellular pre-stress is necessary for robust CDR formation. When treated with agonists that promote contractility, cells increase CDR formation, whereas agonists that inhibit contractility lead to decreased CDR formation. Substrate stiffness promotes CDR formation in response to PDGF by upregulating Src activity through myosin light chain kinase. Together, these data indicate that vessel stiffening accompanying atherogenesis may exacerbate VSMC response to PDGF leading to CDR formation.
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Affiliation(s)
- John Huynh
- Department of Biomedical Engineering, Cornell University, 302 Weill Hall, 526 Campus Road, Ithaca, NY 14853, USA
| | - Francois Bordeleau
- Department of Biomedical Engineering, Cornell University, 302 Weill Hall, 526 Campus Road, Ithaca, NY 14853, USA
| | - Casey M Kraning-Rush
- Department of Biomedical Engineering, Cornell University, 302 Weill Hall, 526 Campus Road, Ithaca, NY 14853, USA
| | - Cynthia A Reinhart-King
- Department of Biomedical Engineering, Cornell University, 302 Weill Hall, 526 Campus Road, Ithaca, NY 14853, USA
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Boscher C, Nabi IR. Galectin-3- and phospho-caveolin-1-dependent outside-in integrin signaling mediates the EGF motogenic response in mammary cancer cells. Mol Biol Cell 2013; 24:2134-45. [PMID: 23657817 PMCID: PMC3694797 DOI: 10.1091/mbc.e13-02-0095] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Galectin-3 binding to N-glycans promotes EGF receptor signaling to integrin in mammary cancer cells. This leads to phospho-caveolin-1–, Src-, and ILK-dependent activation of RhoA, resulting in actin reorganization in circular dorsal ruffles, cell migration, and fibronectin remodeling. In murine mammary epithelial cancer cells, galectin-3 binding to β1,6-acetylglucosaminyltransferase V (Mgat5)–modified N-glycans restricts epidermal growth factor (EGF) receptor mobility in the plasma membrane and acts synergistically with phospho-caveolin-1 to promote integrin-dependent matrix remodeling and cell migration. We show that EGF signaling to RhoA is galectin-3 and phospho-caveolin-1 dependent and promotes the formation of transient, actin-rich, circular dorsal ruffles (CDRs), cell migration, and fibronectin fibrillogenesis via Src- and integrin-linked kinase (ILK)–dependent signaling. ILK, Src, and galectin-3 also mediate EGF stimulation of caveolin-1 phosphorylation. Direct activation of integrin with Mn2+ induces galectin-3, ILK, and Src-dependent RhoA activation and caveolin-1 phosphorylation. This suggests that in response to EGF, galectin-3 enables outside-in integrin signaling stimulating phospho-caveolin-1–dependent RhoA activation, actin reorganization in CDRs, cell migration, and fibronectin remodeling. Similarly, caveolin-1/galectin-3–dependent EGF signaling induces motility, peripheral actin ruffling, and RhoA activation in MDA-MB-231 human breast carcinoma cells, but not HeLa cells. These studies define a galectin-3/phospho-caveolin-1/RhoA signaling module that mediates integrin signaling downstream of growth factor activation, leading to actin and matrix remodeling and tumor cell migration in metastatic cancer cells.
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Affiliation(s)
- Cecile Boscher
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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Hoffmann M, Schwarz US. A kinetic model for RNA-interference of focal adhesions. BMC SYSTEMS BIOLOGY 2013; 7:2. [PMID: 23311633 PMCID: PMC3616989 DOI: 10.1186/1752-0509-7-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 12/21/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Focal adhesions are integrin-based cell-matrix contacts that transduce and integrate mechanical and biochemical cues from the environment. They develop from smaller and more numerous focal complexes under the influence of mechanical force and are key elements for many physiological and disease-related processes, including wound healing and metastasis. More than 150 different proteins localize to focal adhesions and have been systematically classified in the adhesome project (http://www.adhesome.org). First RNAi-screens have been performed for focal adhesions and the effect of knockdown of many of these components on the number, size, shape and location of focal adhesions has been reported. RESULTS We have developed a kinetic model for RNA interference of focal adhesions which represents some of its main elements: a spatially layered structure, signaling through the small GTPases Rac and Rho, and maturation from focal complexes to focal adhesions under force. The response to force is described by two complementary scenarios corresponding to slip and catch bond behavior, respectively. Using estimated and literature values for the model parameters, three time scales of the dynamics of RNAi-influenced focal adhesions are identified: a sub-minute time scale for the assembly of focal complexes, a sub-hour time scale for the maturation to focal adhesions, and a time scale of days that controls the siRNA-mediated knockdown. Our model shows bistability between states dominated by focal complexes and focal adhesions, respectively. Catch bonding strongly extends the range of stability of the state dominated by focal adhesions. A sensitivity analysis predicts that knockdown of focal adhesion components is more efficient for focal adhesions with slip bonds or if the system is in a state dominated by focal complexes. Knockdown of Rho leads to an increase of focal complexes. CONCLUSIONS The suggested model provides a kinetic description of the effect of RNA-interference of focal adhesions. Its predictions are in good agreement with known experimental results and can now guide the design of RNAi-experiments. In the future, it can be extended to include more components of the adhesome. It also could be extended by spatial aspects, for example by the differential activation of the Rac- and Rho-pathways in different parts of the cell.
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Affiliation(s)
- Max Hoffmann
- BioQuant, Heidelberg University, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
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Itoh T, Hasegawa J. Mechanistic insights into the regulation of circular dorsal ruffle formation. J Biochem 2012; 153:21-9. [PMID: 23175656 DOI: 10.1093/jb/mvs138] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Growth factor stimulations induce dynamic changes in the cytoskeleton beneath the plasma membrane. Among them is the formation of membrane ruffles organized in a circular array, called 'circular dorsal ruffles' (CDRs). Physiological functions of CDRs include downregulation of cell growth by desensitizing the signalling from growth factor receptors as well as rearrangement of adhesion sites at the onset of cell migration. For the formation of CDRs, not only the activators of actin polymerization, such as N-WASP and the Arp2/3-complex, but also membrane deforming proteins with BAR/F-BAR domains are necessary. Small GTPases are also involved in the formation of CDRs by controlling intracellular trafficking through endosomes. Moreover, recent analyses of another circular cytoskeletal structure, podosome rosettes, have revealed common molecular features shared with CDRs. Among them, the roles of PI3-kinase and phosphoinositide 5-phosphatase may hold the key to the induction of these circular structures.
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Affiliation(s)
- Toshiki Itoh
- Division of Membrane Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Kobe 650-0017, Japan.
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Allard J, Mogilner A. Traveling waves in actin dynamics and cell motility. Curr Opin Cell Biol 2012; 25:107-15. [PMID: 22985541 DOI: 10.1016/j.ceb.2012.08.012] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/20/2012] [Accepted: 08/23/2012] [Indexed: 11/26/2022]
Abstract
Much of current understanding of cell motility arose from studying steady treadmilling of actin arrays. Recently, there have been a growing number of observations of a more complex, non-steady, actin behavior, including self-organized waves. It is becoming clear that these waves result from activation and inhibition feedbacks in actin dynamics acting on different scales, but the exact molecular nature of these feedbacks and the respective roles of biomechanics and biochemistry are still unclear. Here, we review recent advances achieved in experimental and theoretical studies of actin waves and discuss mechanisms and physiological significance of wavy protrusions.
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Affiliation(s)
- Jun Allard
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, CA 95616, USA.
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Abstract
Cells construct a number of plasma membrane structures to meet a range of physiological demands. Driven by juxtamembrane actin machinery, these actin-based membrane protrusions are essential for the operation and maintenance of cellular life. They are required for diverse cellular functions, such as directed cell motility, cell spreading, adhesion, and substrate/matrix degradation. Circular dorsal ruffles (CDRs) are one class of such structures characterized as F-actin-rich membrane projections on the apical cell surface. CDRs commence their formation minutes after stimulation as flat, open, and immature ruffles and progressively develop into fully enclosed circular ruffles. These "rings" then mature and contract centrifugally before subsiding. Serving a critical function in receptor internalization and cell migration, CDRs are thus highly dynamic but transient formations. Here, we review the current state of knowledge concerning the regulation of circular dorsal ruffles. We focus specifically on the biochemical pathways leading to CDR formation in order to better define the roles and functions of these enigmatic structures.
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Hasegawa J, Tsujita K, Takenawa T, Itoh T. ARAP1 regulates the ring size of circular dorsal ruffles through Arf1 and Arf5. Mol Biol Cell 2012; 23:2481-9. [PMID: 22573888 PMCID: PMC3386212 DOI: 10.1091/mbc.e12-01-0017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Circular dorsal ruffles (CDRs) are highly dynamic F-actin–based membrane structures involved in bulk endocytosis of membrane receptors and macropinocytosis. A key role of ARAP1, an Arf GAP protein, is found to be in the control of the ring size of CDRs. Small guanosine triphosphatase (GTPase) ADP-ribosylation factors (Arfs) regulate membrane traffic and actin reorganization under the strict control of GTPase-activating proteins (GAPs). ARAP1 (Arf GAP with Rho GAP domain, ankyrin repeat, and PH domain 1) is an Arf GAP molecule with multiple PH domains that recognize phosphatidylinositol 3,4,5-trisphosphate. We found that growth factor stimulation induced localization of ARAP1 to an area of the plasma membrane inside the ring structure of circular dorsal ruffles (CDRs). Moreover, expression of ARAP1 increased the size of the CDR filamentous-actin ring in an Arf GAP activity–dependent manner, whereas smaller CDRs were formed by ARAP1 knockdown. In addition, expression of a dominant-negative mutant of Arf1 and Arf5, the substrates of ARAP1, expanded the size of CDRs, suggesting that the two Arf isoforms regulate ring structure downstream of ARAP1. Therefore our results reveal a novel molecular mechanism of CDR ring size control through the ARAP1–Arf1/5 pathway.
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Affiliation(s)
- Junya Hasegawa
- Division of Membrane Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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