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Zhou L, Na J, Liu X, Wu P. Chromophore-Assisted Light Inactivation for Protein Degradation and Its Application in Biomedicine. Bioengineering (Basel) 2024; 11:651. [PMID: 39061733 PMCID: PMC11273424 DOI: 10.3390/bioengineering11070651] [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: 04/25/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
The functional investigation of proteins holds immense significance in unraveling physiological and pathological mechanisms of organisms as well as advancing the development of novel pharmaceuticals in biomedicine. However, the study of cellular protein function using conventional genetic manipulation methods may yield unpredictable outcomes and erroneous conclusions. Therefore, precise modulation of protein activity within cells holds immense significance in the realm of biomedical research. Chromophore-assisted light inactivation (CALI) is a technique that labels photosensitizers onto target proteins and induces the production of reactive oxygen species through light control to achieve precise inactivation of target proteins. Based on the type and characteristics of photosensitizers, different excitation light sources and labeling methods are selected. For instance, KillerRed forms a fusion protein with the target protein through genetic engineering for labeling and inactivates the target protein via light activation. CALI is presently predominantly employed in diverse biomedical domains encompassing investigations into protein functionality and interaction, intercellular signal transduction research, as well as cancer exploration and therapy. With the continuous advancement of CALI technology, it is anticipated to emerge as a formidable instrument in the realm of life sciences, yielding more captivating outcomes for fundamental life sciences and precise disease diagnosis and treatment.
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Affiliation(s)
- Lvjia Zhou
- State Key Laboratory of Targeting Oncology, National Center for International Research of Bio-Targeting Theranostics, Guangxi Key Laboratory of Bio-Targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Medical University, Nanning 530021, China; (L.Z.); (J.N.)
| | - Jintong Na
- State Key Laboratory of Targeting Oncology, National Center for International Research of Bio-Targeting Theranostics, Guangxi Key Laboratory of Bio-Targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Medical University, Nanning 530021, China; (L.Z.); (J.N.)
| | - Xiyu Liu
- State Key Laboratory of Targeting Oncology, National Center for International Research of Bio-Targeting Theranostics, Guangxi Key Laboratory of Bio-Targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Medical University, Nanning 530021, China; (L.Z.); (J.N.)
| | - Pan Wu
- State Key Laboratory of Targeting Oncology, National Center for International Research of Bio-Targeting Theranostics, Guangxi Key Laboratory of Bio-Targeting Theranostics, Collaborative Innovation Center for Targeting Tumor Diagnosis and Therapy, Guangxi Medical University, Nanning 530021, China; (L.Z.); (J.N.)
- School of Pharmacy, Guangxi Medical University, Nanning 530021, China
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2
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Colin A, Kotila T, Guérin C, Orhant-Prioux M, Vianay B, Mogilner A, Lappalainen P, Théry M, Blanchoin L. Recycling of the actin monomer pool limits the lifetime of network turnover. EMBO J 2023; 42:e112717. [PMID: 36912152 PMCID: PMC10152149 DOI: 10.15252/embj.2022112717] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/10/2023] [Accepted: 02/21/2023] [Indexed: 03/14/2023] Open
Abstract
Intracellular organization is largely mediated by actin turnover. Cellular actin networks continuously assemble and disassemble, while maintaining their overall appearance. This behavior, called "dynamic steady state," allows cells to sense and adapt to their environment. However, how structural stability can be maintained during the constant turnover of a limited actin monomer pool is poorly understood. To answer this question, we developed an experimental system where polystyrene beads are propelled by an actin comet in a microwell containing a limited amount of components. We used the speed and the size of the actin comet tails to evaluate the system's monomer consumption and its lifetime. We established the relative contribution of actin assembly, disassembly, and recycling for a bead movement over tens of hours. Recycling mediated by cyclase-associated protein (CAP) is the key step in allowing the reuse of monomers for multiple assembly cycles. ATP supply and protein aging are also factors that limit the lifetime of actin turnover. This work reveals the balancing mechanism for long-term network assembly with a limited amount of building blocks.
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Affiliation(s)
- Alexandra Colin
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire & Végétale, Interdisciplinary Research Institute of Grenoble, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Tommi Kotila
- Institute of Biotechnology and Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Christophe Guérin
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire & Végétale, Interdisciplinary Research Institute of Grenoble, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Magali Orhant-Prioux
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire & Végétale, Interdisciplinary Research Institute of Grenoble, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France
| | - Benoit Vianay
- CytoMorpho Lab, Institut de Recherche Saint Louis, U976 Human Immunology Pathophysiology Immunotherapy (HIPI), University of Paris, INSERM, CEA, Paris, France
| | - Alex Mogilner
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA.,Department of Biology, New York University, New York, NY, USA
| | - Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Manuel Théry
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire & Végétale, Interdisciplinary Research Institute of Grenoble, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.,CytoMorpho Lab, Institut de Recherche Saint Louis, U976 Human Immunology Pathophysiology Immunotherapy (HIPI), University of Paris, INSERM, CEA, Paris, France
| | - Laurent Blanchoin
- CytoMorpho Lab, Laboratoire de Physiologie Cellulaire & Végétale, Interdisciplinary Research Institute of Grenoble, University of Grenoble-Alpes, CEA, CNRS, INRA, Grenoble, France.,CytoMorpho Lab, Institut de Recherche Saint Louis, U976 Human Immunology Pathophysiology Immunotherapy (HIPI), University of Paris, INSERM, CEA, Paris, France
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3
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Lappalainen P, Kotila T, Jégou A, Romet-Lemonne G. Biochemical and mechanical regulation of actin dynamics. Nat Rev Mol Cell Biol 2022; 23:836-852. [PMID: 35918536 DOI: 10.1038/s41580-022-00508-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2022] [Indexed: 12/30/2022]
Abstract
Polymerization of actin filaments against membranes produces force for numerous cellular processes, such as migration, morphogenesis, endocytosis, phagocytosis and organelle dynamics. Consequently, aberrant actin cytoskeleton dynamics are linked to various diseases, including cancer, as well as immunological and neurological disorders. Understanding how actin filaments generate forces in cells, how force production is regulated by the interplay between actin-binding proteins and how the actin-regulatory machinery responds to mechanical load are at the heart of many cellular, developmental and pathological processes. During the past few years, our understanding of the mechanisms controlling actin filament assembly and disassembly has evolved substantially. It has also become evident that the activities of key actin-binding proteins are not regulated solely by biochemical signalling pathways, as mechanical regulation is critical for these proteins. Indeed, the architecture and dynamics of the actin cytoskeleton are directly tuned by mechanical load. Here we discuss the general mechanisms by which key actin regulators, often in synergy with each other, control actin filament assembly, disassembly, and monomer recycling. By using an updated view of actin dynamics as a framework, we discuss how the mechanics and geometry of actin networks control actin-binding proteins, and how this translates into force production in endocytosis and mesenchymal cell migration.
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Affiliation(s)
- Pekka Lappalainen
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland.
| | - Tommi Kotila
- Institute of Biotechnology and Helsinki Institute of Life Sciences, University of Helsinki, Helsinki, Finland
| | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
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4
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Zieliński T, Pabijan J, Zapotoczny B, Zemła J, Wesołowska J, Pera J, Lekka M. Changes in nanomechanical properties of single neuroblastoma cells as a model for oxygen and glucose deprivation (OGD). Sci Rep 2022; 12:16276. [PMID: 36175469 PMCID: PMC9523022 DOI: 10.1038/s41598-022-20623-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 09/15/2022] [Indexed: 11/21/2022] Open
Abstract
Although complex, the biological processes underlying ischemic stroke are better known than those related to biomechanical alterations of single cells. Mechanisms of biomechanical changes and their relations to the molecular processes are crucial for understanding the function and dysfunction of the brain. In our study, we applied atomic force microscopy (AFM) to quantify the alterations in biomechanical properties in neuroblastoma SH-SY5Y cells subjected to oxygen and glucose deprivation (OGD) and reoxygenation (RO). Obtained results reveal several characteristics. Cell viability remained at the same level, regardless of the OGD and RO conditions, but, in parallel, the metabolic activity of cells decreased with OGD duration. 24 h RO did not recover the metabolic activity fully. Cells subjected to OGD appeared softer than control cells. Cell softening was strongly present in cells after 1 h of OGD and with longer OGD duration, and in RO conditions, cells recovered their mechanical properties. Changes in the nanomechanical properties of cells were attributed to the remodelling of actin filaments, which was related to cofilin-based regulation and impaired metabolic activity of cells. The presented study shows the importance of nanomechanics in research on ischemic-related pathological processes such as stroke.
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Affiliation(s)
- Tomasz Zieliński
- Department of Biophysical Microstructures, Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Joanna Pabijan
- Department of Biophysical Microstructures, Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Bartłomiej Zapotoczny
- Department of Biophysical Microstructures, Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Joanna Zemła
- Department of Biophysical Microstructures, Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342, Kraków, Poland
| | - Julita Wesołowska
- Laboratory of in Vivo and in Vitro Imaging, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31343, Kraków, Poland
| | - Joanna Pera
- Department of Neurology, Faculty of Medicine, Jagiellonian University Medical College, Botaniczna 3, 31503, Kraków, Poland
| | - Małgorzata Lekka
- Department of Biophysical Microstructures, Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342, Kraków, Poland.
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5
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Ishimoto T, Mori H. Control of actin polymerization via reactive oxygen species generation using light or radiation. Front Cell Dev Biol 2022; 10:1014008. [PMID: 36211457 PMCID: PMC9538341 DOI: 10.3389/fcell.2022.1014008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/07/2022] [Indexed: 11/25/2022] Open
Abstract
Actin is one of the most prevalent proteins in cells, and its amino acid sequence is remarkably conserved from protozoa to humans. The polymerization-depolymerization cycle of actin immediately below the plasma membrane regulates cell function, motility, and morphology. It is known that actin and other actin-binding proteins are targets for reactive oxygen species (ROS), indicating that ROS affects cells through actin reorganization. Several researchers have attempted to control actin polymerization from outside the cell to mimic or inhibit actin reorganization. To modify the polymerization state of actin, ultraviolet, visible, and near-infrared light, ionizing radiation, and chromophore-assisted light inactivation have all been reported to induce ROS. Additionally, a combination of the fluorescent protein KillerRed and the luminescent protein luciferase can generate ROS on actin fibers and promote actin polymerization. These techniques are very useful tools for analyzing the relationship between ROS and cell function, movement, and morphology, and are also expected to be used in therapeutics. In this mini review, we offer an overview of the advancements in this field, with a particular focus on how to control intracellular actin polymerization using such optical approaches, and discuss future challenges.
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Affiliation(s)
- Tetsuya Ishimoto
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan
- *Correspondence: Tetsuya Ishimoto,
| | - Hisashi Mori
- Department of Molecular Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan
- Research Center for Idling Brain Science, University of Toyama, Toyama, Japan
- Research Center for Pre-Disease Science, University of Toyama, Toyama, Japan
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6
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King ZT, Butler MT, Hockenberry MA, Subramanian BC, Siesser PF, Graham DM, Legant WR, Bear JE. Coro1B and Coro1C regulate lamellipodia dynamics and cell motility by tuning branched actin turnover. J Cell Biol 2022; 221:e202111126. [PMID: 35657370 PMCID: PMC9170525 DOI: 10.1083/jcb.202111126] [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: 11/24/2021] [Revised: 04/01/2022] [Accepted: 05/18/2022] [Indexed: 02/03/2023] Open
Abstract
Actin filament dynamics must be precisely controlled in cells to execute behaviors such as vesicular trafficking, cytokinesis, and migration. Coronins are conserved actin-binding proteins that regulate several actin-dependent subcellular processes. Here, we describe a new conditional knockout cell line for two ubiquitous coronins, Coro1B and Coro1C. These coronins, which strongly co-localize with Arp2/3-branched actin, require Arp2/3 activity for proper subcellular localization. Coronin null cells have altered lamellipodial protrusion dynamics due to increased branched actin density and reduced actin turnover within lamellipodia, leading to defective haptotaxis. Surprisingly, excessive cofilin accumulates in coronin null lamellipodia, a result that is inconsistent with the current models of coronin-cofilin functional interaction. However, consistent with coronins playing a pro-cofilin role, coronin null cells have increased F-actin levels. Lastly, we demonstrate that the loss of coronins increases accompanied by an increase in cellular contractility. Together, our observations reveal that coronins are critical for proper turnover of branched actin networks and that decreased actin turnover leads to increased cellular contractility.
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Affiliation(s)
- Zayna T. King
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - Mitchell T. Butler
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - Max A. Hockenberry
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - Bhagawat C. Subramanian
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - Priscila F. Siesser
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - David M. Graham
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - Wesley R. Legant
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
| | - James E. Bear
- Department of Cell Biology and Physiology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- University of North Carolina Lineberger Comprehensive Cancer Center, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, Chapel Hill, NC
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7
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Atherton J, Stouffer M, Francis F, Moores CA. Visualising the cytoskeletal machinery in neuronal growth cones using cryo-electron tomography. J Cell Sci 2022; 135:274968. [PMID: 35383828 PMCID: PMC9016625 DOI: 10.1242/jcs.259234] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 03/02/2022] [Indexed: 12/12/2022] Open
Abstract
Neurons extend axons to form the complex circuitry of the mature brain. This depends on the coordinated response and continuous remodelling of the microtubule and F-actin networks in the axonal growth cone. Growth cone architecture remains poorly understood at nanoscales. We therefore investigated mouse hippocampal neuron growth cones using cryo-electron tomography to directly visualise their three-dimensional subcellular architecture with molecular detail. Our data showed that the hexagonal arrays of actin bundles that form filopodia penetrate and terminate deep within the growth cone interior. We directly observed the modulation of these and other growth cone actin bundles by alteration of individual F-actin helical structures. Microtubules with blunt, slightly flared or gently curved ends predominated in the growth cone, frequently contained lumenal particles and exhibited lattice defects. Investigation of the effect of absence of doublecortin, a neurodevelopmental cytoskeleton regulator, on growth cone cytoskeleton showed no major anomalies in overall growth cone organisation or in F-actin subpopulations. However, our data suggested that microtubules sustained more structural defects, highlighting the importance of microtubule integrity during growth cone migration. Summary: Cryo-electron tomographic reconstruction of neuronal growth cone subdomains reveals distinctive F-actin and microtubule cytoskeleton architectures and modulation at molecular detail.
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Affiliation(s)
- Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King's College, London SE1 1YR, UK.,Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
| | - Melissa Stouffer
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France.,Institute of Science and Technology Austria, Am campus 1, 3400 Klosterneuberg, Austria
| | - Fiona Francis
- INSERM UMR-S 1270, 17 Rue du Fer à Moulin, 75005 Paris, France.,Sorbonne University UMR-S 1270, 4 Place Jussieu, 75005 Paris, France.,Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005 Paris, France
| | - Carolyn A Moores
- Institute of Structural and Molecular Biology, Birkbeck, University of London, London WC1E 7HX, UK
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8
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Goto A, Bota A, Miya K, Wang J, Tsukamoto S, Jiang X, Hirai D, Murayama M, Matsuda T, McHugh TJ, Nagai T, Hayashi Y. Stepwise synaptic plasticity events drive the early phase of memory consolidation. Science 2021; 374:857-863. [PMID: 34762472 DOI: 10.1126/science.abj9195] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Akihiro Goto
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Ayaka Bota
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Ken Miya
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Department of Molecular Neurobiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan.,Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Jingbo Wang
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Suzune Tsukamoto
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Xinzhi Jiang
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan
| | - Daichi Hirai
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Masanori Murayama
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Tomoki Matsuda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Thomas J McHugh
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
| | - Takeharu Nagai
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan.,RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,Brain and Body System Science Institute, Saitama University, Saitama 338-8570, Japan
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9
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Edwards P, Skruber K, Milićević N, Heidings JB, Read TA, Bubenik P, Vitriol EA. TDAExplore: Quantitative analysis of fluorescence microscopy images through topology-based machine learning. PATTERNS 2021; 2:100367. [PMID: 34820649 PMCID: PMC8600226 DOI: 10.1016/j.patter.2021.100367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/31/2021] [Accepted: 09/20/2021] [Indexed: 11/02/2022]
Abstract
Recent advances in machine learning have greatly enhanced automatic methods to extract information from fluorescence microscopy data. However, current machine-learning-based models can require hundreds to thousands of images to train, and the most readily accessible models classify images without describing which parts of an image contributed to classification. Here, we introduce TDAExplore, a machine learning image analysis pipeline based on topological data analysis. It can classify different types of cellular perturbations after training with only 20–30 high-resolution images and performs robustly on images from multiple subjects and microscopy modes. Using only images and whole-image labels for training, TDAExplore provides quantitative, spatial information, characterizing which image regions contribute to classification. Computational requirements to train TDAExplore models are modest and a standard PC can perform training with minimal user input. TDAExplore is therefore an accessible, powerful option for obtaining quantitative information about imaging data in a wide variety of applications. TDAExplore combines topological data analysis with machine learning classification As few as 20–30 high-resolution images can be used to train TDAExplore models TDAExplore is robust to different microscopy modes, dataset size, image features TDAExplore quantifies where and how much each image resembles the training data
Traditional intensity-based measurements of fluorescent microscopy data limit its potential to reveal new information about its sample. Here, we present an image analysis pipeline called TDAExplore, which is based on topological data analysis and machine learning classification. In addition to being highly accurate in assigning images to their correct group, TDAExplore quantifies how much images resemble the training data and identifies which parts are different, an improvement over other machine learning models that do not permit insight into how classification tasks were made. The next steps for TDAExplore will be to expand its capabilities into three-dimensional, multivariate, and time series datasets. This work represents progress into a future where machine learning identifies and describes nuanced image features in ways that allow researchers to answer important biological questions and generate new hypotheses for future studies.
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10
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Ullo MF, Logue JS. ADF and cofilin-1 collaborate to promote cortical actin flow and the leader bleb-based migration of confined cells. eLife 2021; 10:67856. [PMID: 34169836 PMCID: PMC8253594 DOI: 10.7554/elife.67856] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 06/22/2021] [Indexed: 01/16/2023] Open
Abstract
Melanoma cells have been shown to undergo fast amoeboid (leader bleb-based) migration, requiring a single large bleb for migration. In leader blebs, is a rapid flow of cortical actin that drives the cell forward. Using RNAi, we find that co-depleting cofilin-1 and actin depolymerizing factor (ADF) led to a large increase in cortical actin, suggesting that both proteins regulate cortical actin. Furthermore, severing factors can promote contractility through the regulation of actin architecture. However, RNAi of cofilin-1 but not ADF led to a significant decrease in cell stiffness. We found cofilin-1 to be enriched at leader bleb necks, whereas RNAi of cofilin-1 and ADF reduced bleb sizes and the frequency of motile cells. Strikingly, cells without cofilin-1 and ADF had blebs with abnormally long necks. Many of these blebs failed to retract and displayed slow actin turnover. Collectively, our data identifies cofilin-1 and ADF as actin remodeling factors required for fast amoeboid migration.
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Affiliation(s)
- Maria F Ullo
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, United States
| | - Jeremy S Logue
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, United States
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11
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Bolger-Munro M, Choi K, Cheung F, Liu YT, Dang-Lawson M, Deretic N, Keane C, Gold MR. The Wdr1-LIMK-Cofilin Axis Controls B Cell Antigen Receptor-Induced Actin Remodeling and Signaling at the Immune Synapse. Front Cell Dev Biol 2021; 9:649433. [PMID: 33928084 PMCID: PMC8076898 DOI: 10.3389/fcell.2021.649433] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/12/2021] [Indexed: 12/27/2022] Open
Abstract
When B cells encounter membrane-bound antigens, the formation and coalescence of B cell antigen receptor (BCR) microclusters amplifies BCR signaling. The ability of B cells to probe the surface of antigen-presenting cells (APCs) and respond to APC-bound antigens requires remodeling of the actin cytoskeleton. Initial BCR signaling stimulates actin-related protein (Arp) 2/3 complex-dependent actin polymerization, which drives B cell spreading as well as the centripetal movement and coalescence of BCR microclusters at the B cell-APC synapse. Sustained actin polymerization depends on concomitant actin filament depolymerization, which enables the recycling of actin monomers and Arp2/3 complexes. Cofilin-mediated severing of actin filaments is a rate-limiting step in the morphological changes that occur during immune synapse formation. Hence, regulators of cofilin activity such as WD repeat-containing protein 1 (Wdr1), LIM domain kinase (LIMK), and coactosin-like 1 (Cotl1) may also be essential for actin-dependent processes in B cells. Wdr1 enhances cofilin-mediated actin disassembly. Conversely, Cotl1 competes with cofilin for binding to actin and LIMK phosphorylates cofilin and prevents it from binding to actin filaments. We now show that Wdr1 and LIMK have distinct roles in BCR-induced assembly of the peripheral actin structures that drive B cell spreading, and that cofilin, Wdr1, and LIMK all contribute to the actin-dependent amplification of BCR signaling at the immune synapse. Depleting Cotl1 had no effect on these processes. Thus, the Wdr1-LIMK-cofilin axis is critical for BCR-induced actin remodeling and for B cell responses to APC-bound antigens.
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Affiliation(s)
- Madison Bolger-Munro
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Kate Choi
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Faith Cheung
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Yi Tian Liu
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - May Dang-Lawson
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Nikola Deretic
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Connor Keane
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michael R Gold
- Department of Microbiology & Immunology and Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
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12
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Indra I, Troyanovsky RB, Shapiro L, Honig B, Troyanovsky SM. Sensing Actin Dynamics through Adherens Junctions. Cell Rep 2021; 30:2820-2833.e3. [PMID: 32101754 DOI: 10.1016/j.celrep.2020.01.106] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 12/23/2019] [Accepted: 01/29/2020] [Indexed: 11/19/2022] Open
Abstract
We study punctate adherens junctions (pAJs) to determine how short-lived cadherin clusters and relatively stable actin bundles interact despite differences in dynamics. We show that pAJ-linked bundles consist of two distinct regions-the bundle stalk (AJ-BS) and a tip (AJ-BT) positioned between cadherin clusters and the stalk. The tip differs from the stalk in a number of ways: it is devoid of the actin-bundling protein calponin, and exhibits a much faster F-actin turnover rate. While F-actin in the stalk displays centripetal movement, the F-actin in the tip is immobile. The F-actin turnover in both the tip and stalk is dependent on cadherin cluster stability, which in turn is regulated by F-actin. The close bidirectional coupling between the stability of cadherin and associated F-actin shows how pAJs, and perhaps other AJs, allow cells to sense and coordinate the dynamics of the actin cytoskeleton in neighboring cells-a mechanism we term "dynasensing."
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Affiliation(s)
- Indrajyoti Indra
- Department of Dermatology, Northwestern University, The Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Regina B Troyanovsky
- Department of Dermatology, Northwestern University, The Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10032, USA.
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Medicine, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain and Behavior Institute, Columbia University, New York, NY 10032, USA.
| | - Sergey M Troyanovsky
- Department of Dermatology, Northwestern University, The Feinberg School of Medicine, Chicago, IL 60611, USA.
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13
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TAKEMOTO K. Optical manipulation of molecular function by chromophore-assisted light inactivation. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:197-209. [PMID: 33840676 PMCID: PMC8062263 DOI: 10.2183/pjab.97.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
In addition to simple on/off switches for molecular activity, spatiotemporal dynamics are also thought to be important for the regulation of cellular function. However, their physiological significance and in vivo importance remain largely unknown. Fluorescence imaging technology is a powerful technique that can reveal the spatiotemporal dynamics of molecular activity. In addition, because imaging detects the correlations between molecular activity and biological phenomena, the technique of molecular manipulation is also important to analyze causal relationships. Recent advances in optical manipulation techniques that artificially perturb molecules and cells via light can address this issue to elucidate the causality between manipulated target and its physiological function. The use of light enables the manipulation of molecular activity in microspaces, such as organelles and nerve spines. In this review, we describe the chromophore-assisted light inactivation method, which is an optical manipulation technique that has been attracting attention in recent years.
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Affiliation(s)
- Kiwamu TAKEMOTO
- Department of Biochemistry, Mie University, Graduate School of Medicine, Tsu-City, Mie, Japan
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14
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Skruber K, Warp PV, Shklyarov R, Thomas JD, Swanson MS, Henty-Ridilla JL, Read TA, Vitriol EA. Arp2/3 and Mena/VASP Require Profilin 1 for Actin Network Assembly at the Leading Edge. Curr Biol 2020; 30:2651-2664.e5. [PMID: 32470361 DOI: 10.1016/j.cub.2020.04.085] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/09/2020] [Accepted: 04/29/2020] [Indexed: 12/27/2022]
Abstract
Cells have many types of actin structures, which must assemble from a common monomer pool. Yet, it remains poorly understood how monomers are distributed to and shared between different filament networks. Simplified model systems suggest that monomers are limited and heterogeneous, which alters actin network assembly through biased polymerization and internetwork competition. However, less is known about how monomers influence complex actin structures, where different networks competing for monomers overlap and are functionally interdependent. One example is the leading edge of migrating cells, which contains filament networks generated by multiple assembly factors. The leading edge dynamically switches between the formation of different actin structures, such as lamellipodia or filopodia, by altering the balance of these assembly factors' activities. Here, we sought to determine how the monomer-binding protein profilin 1 (PFN1) controls the assembly and organization of actin in mammalian cells. Actin polymerization in PFN1 knockout cells was severely disrupted, particularly at the leading edge, where both Arp2/3 and Mena/VASP-based filament assembly was inhibited. Further studies showed that in the absence of PFN1, Arp2/3 no longer localizes to the leading edge and Mena/VASP is non-functional. Additionally, we discovered that discrete stages of internetwork competition and collaboration between Arp2/3 and Mena/VASP networks exist at different PFN1 concentrations. Low levels of PFN1 caused filopodia to form exclusively at the leading edge, while higher concentrations inhibited filopodia and favored lamellipodia and pre-filopodia bundles. These results demonstrate that dramatic changes to actin architecture can be made simply by modifying PFN1 availability.
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Affiliation(s)
- Kristen Skruber
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Peyton V Warp
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Rachael Shklyarov
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - James D Thomas
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics, and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Jessica L Henty-Ridilla
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, NY 13210, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, College of Medicine, Gainesville, FL 32610, USA; Center for Translational Research in Neurodegenerative Disease, University of Florida, College of Medicine, Gainesville, FL 32610, USA.
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15
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Yolland L, Burki M, Marcotti S, Luchici A, Kenny FN, Davis JR, Serna-Morales E, Müller J, Sixt M, Davidson A, Wood W, Schumacher LJ, Endres RG, Miodownik M, Stramer BM. Persistent and polarized global actin flow is essential for directionality during cell migration. Nat Cell Biol 2019; 21:1370-1381. [PMID: 31685997 PMCID: PMC7025891 DOI: 10.1038/s41556-019-0411-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/23/2019] [Indexed: 12/11/2022]
Abstract
Cell migration is hypothesized to involve a cycle of behaviours beginning with leading edge extension. However, recent evidence suggests that the leading edge may be dispensable for migration, raising the question of what actually controls cell directionality. Here, we exploit the embryonic migration of Drosophila macrophages to bridge the different temporal scales of the behaviours controlling motility. This approach reveals that edge fluctuations during random motility are not persistent and are weakly correlated with motion. In contrast, flow of the actin network behind the leading edge is highly persistent. Quantification of actin flow structure during migration reveals a stable organization and asymmetry in the cell-wide flowfield that strongly correlates with cell directionality. This organization is regulated by a gradient of actin network compression and destruction, which is controlled by myosin contraction and cofilin-mediated disassembly. It is this stable actin-flow polarity, which integrates rapid fluctuations of the leading edge, that controls inherent cellular persistence.
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Affiliation(s)
- Lawrence Yolland
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
- Department of Mechanical Engineering, University College London, London, UK
| | - Mubarik Burki
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Stefania Marcotti
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Andrei Luchici
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
- Dacian Consulting, London, UK
| | - Fiona N Kenny
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - John Robert Davis
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
- The Francis Crick Institute, London, UK
| | | | - Jan Müller
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, Klosterneuburg, Austria
| | - Michael Sixt
- Institute of Science and Technology Austria (IST Austria), Am Campus 1, Klosterneuburg, Austria
| | - Andrew Davidson
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - Will Wood
- Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - Linus J Schumacher
- Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
| | - Robert G Endres
- Department of Life Sciences, Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London, UK
| | - Mark Miodownik
- Department of Mechanical Engineering, University College London, London, UK
| | - Brian M Stramer
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK.
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16
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Liu T, Woo JAA, Yan Y, LePochat P, Bukhari MZ, Kang DE. Dual role of cofilin in APP trafficking and amyloid-β clearance. FASEB J 2019; 33:14234-14247. [PMID: 31646885 DOI: 10.1096/fj.201901268r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The accumulation of amyloid-β (Aβ) plays a pivotal early event in the pathogenesis of Alzheimer's disease (AD). In the brain, neurons produce Aβ by the proteolytic processing of amyloid precursor protein (APP) through the endocytic pathway, whereas microglia mediate Aβ clearance also via endocytic mechanisms. Previous studies have shown the critical importance of cofilin, a filamentous actin-severing protein, in actin dynamics and pathogen-triggered endocytic processes. Moreover, the binding of Aβ42 oligomers to β1-integrin triggers the cofilin activation, and in turn, cofilin promotes the internalization of surface β1-integrin. However, a role for cofilin in APP processing and Aβ metabolism has not been investigated. In this study, we found that knockdown of cofilin in Chinese hamster ovary 7WD10 cells and primary neurons significantly reduces Aβ production by increasing surface APP (sAPP) levels. Expression of active (S3A) but not inactive (S3E) cofilin reduces sAPP levels by enhancing APP endocytosis. Accordingly, Aβ deposition in APP and presenilin 1 (PS1) transgenic mice is significantly reduced by genetic reduction of cofilin (APP/PS1;cofilin+/-). However, the reduction of Aβ load in APP/PS1;cofilin+/- mice is paradoxically associated with significantly increased ionized calcium-binding adaptor molecule 1-positive microglial activation surrounding Aβ deposits. Primary microglia isolated from cofilin+/- mice demonstrate significantly enhanced state of activation and greater ability to uptake and clear Aβ42, which is reversed with the active (S3A) but not inactive (S3E) form of cofilin. These results taken together indicate a significant role for cofilin in Aβ accumulation via dual and opposing endocytic mechanisms of promoting Aβ production in neurons and inhibiting Aβ clearance in microglia.-Liu, T., Woo, J.-A. A., Yan, Y., LePochat, P., Bukhari, M. Z., Kang, D. E. Dual role of cofilin in APP trafficking and amyloid-β clearance.
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Affiliation(s)
- Tian Liu
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular of Medicine, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA
| | - Jung-A A Woo
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA
| | - Yan Yan
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular of Medicine, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA
| | - Patrick LePochat
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular of Medicine, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA
| | - Mohammed Zaheen Bukhari
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular of Medicine, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA
| | - David E Kang
- Byrd Alzheimer's Institute, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,Department of Molecular of Medicine, Morsani College of Medicine, University of South Florida (USF) Health, Tampa, Florida, USA.,James A. Haley Veterans Administration Hospital, Tampa, Florida, USA
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17
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Qin Y, Li W, Long Y, Zhan Z. Relationship between p-cofilin and cisplatin resistance in patients with ovarian cancer and the role of p-cofilin in prognosis. Cancer Biomark 2019; 24:469-475. [PMID: 30932883 DOI: 10.3233/cbm-182209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE This study aims to determine the correlation between p-cofilin expression and cisplatin resistance in patients with ovarian cancer, and also to investigate the role of p-cofilin in prognosis. PATIENTS AND METHODS The ovarian cancer cell line A2780/DDP resistant to cisplatin was prepared. The cell resistance to cisplatin was measured via MTT assay. The cell invasion capacity was identified via Transwell assay. The mRNA expression and protein level was evaluated via semi-quantitative PCR and Western blot, respectively. The tumor tissues of patients with cisplatin-resistant ovarian cancer were collected. The relationship between prognosis and p-cofilin expression was analyzed. RESULTS The growth rate of A2780 was similar to that of A2780/DDP. The sensitivity of A2780 to cisplatin was significantly higher than that of A2780/DDP (p< 0.01). The migration capacity of A2780/DDP was significantly increased compared to that of A2780 (p< 0.01), indicating that the cisplatin-resistant cell lines were successfully constructed. Both CFL1 mRNA level and p-cofilin level in A2780/DDP was significantly higher than that in A2780 (p< 0.01). The p-cofilin level in cancer tissues in patients with cisplatin-resistant ovarian cancer was significantly higher than that in patients with cisplatin-sensitive ovarian cancer (p< 0.01). The cisplatin resistance was positively correlated with the p-cofilin expression level (r= 0.802, p= 0.023). The survival time of patients with normal or low level of p-cofilin was significantly longer than that of patients with high expression. CONCLUSION The cisplatin resistance of ovarian cancer is closely related to the expression level of p-cofilin, which affects the prognosis of patients with ovarian cancer.
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18
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Haar LL, Lawrence DS, Hughes RM. Optogenetic perturbation of the biochemical pathways that control cell behavior. Methods Enzymol 2019; 622:309-328. [PMID: 31155059 DOI: 10.1016/bs.mie.2019.02.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Optogenetic tools provide a level of spatial and temporal resolution needed to shed new light on dynamic intercellular processes. In this chapter we outline specific protocols for applying these tools to cell motility (optogenetic cofilin), apoptosis [optogenetic Bcl-like protein 4 (Bax)], and protein kinase-mediated signaling pathways [optogenetic cAMP-dependent protein kinase (PKA)]. The activity of these optogenetic species is regulated by the light-mediated dimerization of a cryptochrome/Cib protein pair, which controls the intracellular positioning of the protein of interest. The light induced recruitment of cofilin to the cytoskeleton is utilized for directed migration studies and filopodial dynamics. Light-triggered migration of Bax to the outer mitochondrial membrane induces cellular collapse and eventual apoptosis. Finally, the light-mediated movement of PKA to specific intracellular compartments offers the means to assess the consequences of PKA activity in a site-specific fashion via phosphoproteomic analysis.
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Affiliation(s)
- Lauren L Haar
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, United States
| | - David S Lawrence
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, United States; Department of Pharmacology, University of North Carolina, Chapel Hill, NC, United States.
| | - Robert M Hughes
- Department of Chemistry, East Carolina University, Greenville, NC, United States.
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19
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Zimmerman JF, Ardoña HAM, Pyrgiotakis G, Dong J, Moudgil B, Demokritou P, Parker KK. Scatter Enhanced Phase Contrast Microscopy for Discriminating Mechanisms of Active Nanoparticle Transport in Living Cells. NANO LETTERS 2019; 19:793-804. [PMID: 30616354 PMCID: PMC6588408 DOI: 10.1021/acs.nanolett.8b03903] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Understanding the uptake and transport dynamics of engineered nanomaterials (ENMs) by mammalian cells is an important step in designing next-generation drug delivery systems. However, to track these materials and their cellular interactions, current studies often depend on surface-bound fluorescent labels, which have the potential to alter native cellular recognition events. As a result, there is still a need to develop methods capable of monitoring ENM-cell interactions independent of surface modification. Addressing these concerns, here we show how scatter enhanced phase contrast (SEPC) microscopy can be extended to work as a generalized label-free approach for monitoring nanoparticle uptake and transport dynamics. To determine which materials can be studied using SEPC, we turn to Lorenz-Mie theory, which predicts that individual particles down to ∼35 nm can be observed. We confirm this experimentally, demonstrating that SEPC works for a variety of metal and metal oxides, including Au, Ag, TiO2, CeO2, Al2O3, and Fe2O3 nanoparticles. We then demonstrate that SEPC microscopy can be used in a quantitative, time-dependent fashion to discriminate between distinct modes of active cellular transport, including intracellular transport and membrane-assisted transport. Finally, we combine this technique with microcontact printing to normalize transport dynamics across multiple cells, allowing for a careful study of ensemble TiO2 nanoparticle uptake. This revealed three distinct regions of particle transport across the cell, indicating that membrane dynamics play an important role in regulating particle flow. By avoiding fluorescent labels, SEPC allows for a rational exploration of the surface properties of nanomaterials in their native state and their role in endocytosis and cellular transport.
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Affiliation(s)
- John F. Zimmerman
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts, USA
| | - Herdeline Ann M. Ardoña
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts, USA
| | - Georgios Pyrgiotakis
- Center for Nanotechnology and Nanotoxicology, Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, MA, 02138, USA
| | - Jiaqi Dong
- Department of Materials Science & Engineering and Particle Engineering Research Center, PO BOX 116135, University of Florida, Gainesville, FL, 32611, USA
| | - Brij Moudgil
- Department of Materials Science & Engineering and Particle Engineering Research Center, PO BOX 116135, University of Florida, Gainesville, FL, 32611, USA
| | - Philip Demokritou
- Center for Nanotechnology and Nanotoxicology, Harvard T.H. Chan School of Public Health, Harvard University, Cambridge, MA, 02138, USA
| | - Kevin Kit Parker
- Disease Biophysics Group, John A. Paulson School of Engineering and Applied Sciences, Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts, USA
- Corresponding Author: Professor Kevin Kit Parker, 29 Oxford St., Pierce Hall 321, Cambridge, Massachusetts, 02138, USA. ; Fax: +(617) 495 9837; Tel: +(617) 495 2850
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20
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Innocenti M. New insights into the formation and the function of lamellipodia and ruffles in mesenchymal cell migration. Cell Adh Migr 2018. [PMID: 29513145 DOI: 10.1080/19336918.2018.1448352] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lamellipodia and ruffles are veil-shaped cell protrusions composed of a highly branched actin filament meshwork assembled by the Arp2/3 complex. These structures not only hallmark the leading edge of cells adopting the adhesion-based mesenchymal mode of migration but are also thought to drive cell movement. Although regarded as textbook knowledge, the mechanism of formation of lamellipodia and ruffles has been revisited in the last years leveraging new technologies. Furthermore, recent observations have also challenged our current view of the function of lamellipodia and ruffles in mesenchymal cell migration. Here, I review this literature and compare it with older studies to highlight the controversies and the outstanding open issues in the field. Moreover, I outline simple and plausible explanations to reconcile conflicting results and conclusions. Finally, I integrate the mechanisms regulating actin-based protrusion in a unifying model that accounts for random and ballistic mesenchymal cell migration.
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Affiliation(s)
- Metello Innocenti
- a Division of Molecular Genetics, The Netherlands Cancer Institute , Plesmanlaan 121, Amsterdam , CX , The Netherlands
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21
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Skruber K, Read TA, Vitriol EA. Reconsidering an active role for G-actin in cytoskeletal regulation. J Cell Sci 2018; 131:131/1/jcs203760. [PMID: 29321224 DOI: 10.1242/jcs.203760] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Globular (G)-actin, the actin monomer, assembles into polarized filaments that form networks that can provide structural support, generate force and organize the cell. Many of these structures are highly dynamic and to maintain them, the cell relies on a large reserve of monomers. Classically, the G-actin pool has been thought of as homogenous. However, recent work has shown that actin monomers can exist in distinct groups that can be targeted to specific networks, where they drive and modify filament assembly in ways that can have profound effects on cellular behavior. This Review focuses on the potential factors that could create functionally distinct pools of actin monomers in the cell, including differences between the actin isoforms and the regulation of G-actin by monomer binding proteins, such as profilin and thymosin β4. Owing to difficulties in studying and visualizing G-actin, our knowledge over the precise role that specific actin monomer pools play in regulating cellular actin dynamics remains incomplete. Here, we discuss some of these unanswered questions and also provide a summary of the methodologies currently available for the imaging of G-actin.
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Affiliation(s)
- Kristen Skruber
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
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22
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Elam WA, Cao W, Kang H, Huehn A, Hocky GM, Prochniewicz E, Schramm AC, Negrón K, Garcia J, Bonello TT, Gunning PW, Thomas DD, Voth GA, Sindelar CV, De La Cruz EM. Phosphomimetic S3D cofilin binds but only weakly severs actin filaments. J Biol Chem 2017; 292:19565-19579. [PMID: 28939776 DOI: 10.1074/jbc.m117.808378] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/18/2017] [Indexed: 12/30/2022] Open
Abstract
Many biological processes, including cell division, growth, and motility, rely on rapid remodeling of the actin cytoskeleton and on actin filament severing by the regulatory protein cofilin. Phosphorylation of vertebrate cofilin at Ser-3 regulates both actin binding and severing. Substitution of serine with aspartate at position 3 (S3D) is widely used to mimic cofilin phosphorylation in cells and in vitro The S3D substitution weakens cofilin binding to filaments, and it is presumed that subsequent reduction in cofilin occupancy inhibits filament severing, but this hypothesis has remained untested. Here, using time-resolved phosphorescence anisotropy, electron cryomicroscopy, and all-atom molecular dynamics simulations, we show that S3D cofilin indeed binds filaments with lower affinity, but also with a higher cooperativity than wild-type cofilin, and severs actin weakly across a broad range of occupancies. We found that three factors contribute to the severing deficiency of S3D cofilin. First, the high cooperativity of S3D cofilin generates fewer boundaries between bare and decorated actin segments where severing occurs preferentially. Second, S3D cofilin only weakly alters filament bending and twisting dynamics and therefore does not introduce the mechanical discontinuities required for efficient filament severing at boundaries. Third, Ser-3 modification (i.e. substitution with Asp or phosphorylation) "undocks" and repositions the cofilin N terminus away from the filament axis, which compromises S3D cofilin's ability to weaken longitudinal filament subunit interactions. Collectively, our results demonstrate that, in addition to inhibiting actin binding, Ser-3 modification favors formation of a cofilin-binding mode that is unable to sufficiently alter filament mechanical properties and promote severing.
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Affiliation(s)
- W Austin Elam
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Wenxiang Cao
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Hyeran Kang
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Andrew Huehn
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Glen M Hocky
- the Department of Chemistry, University of Chicago, Chicago, Illinois 60637
| | - Ewa Prochniewicz
- the Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, and
| | - Anthony C Schramm
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Karina Negrón
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Jean Garcia
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Teresa T Bonello
- the School of Medical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Peter W Gunning
- the School of Medical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - David D Thomas
- the Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, and
| | - Gregory A Voth
- the Department of Chemistry, University of Chicago, Chicago, Illinois 60637
| | - Charles V Sindelar
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Enrique M De La Cruz
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520,
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23
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Zafar S, Younas N, Sheikh N, Tahir W, Shafiq M, Schmitz M, Ferrer I, Andréoletti O, Zerr I. Cytoskeleton-Associated Risk Modifiers Involved in Early and Rapid Progression of Sporadic Creutzfeldt-Jakob Disease. Mol Neurobiol 2017; 55:4009-4029. [PMID: 28573459 DOI: 10.1007/s12035-017-0589-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/28/2017] [Indexed: 10/19/2022]
Abstract
A high priority in the prion field is to identify pre-symptomatic events and associated profile of molecular changes. In this study, we demonstrate the pre-symptomatic dysregulation of cytoskeleton assembly and its associated cofilin-1 pathway in strain and brain region-specific manners in MM1 and VV2 subtype-specific Creutzfeldt-Jakob disease at clinical and pre-clinical stage. At physiological level, PrPC interaction with cofilin-1 and phosphorylated form of cofilin (p-cofilin(Ser3)) was investigated in primary cultures of mouse cortex neurons (PCNs) of PrPC wild-type and knockout mice (PrP-/-). Short-interfering RNA downregulation of active form of cofilin-1 resulted in the redistribution/downregulation of PrPC, increase of activated form of microglia, accumulation of dense form of F-actin, and upregulation of p-cofilin(Ser3). This upregulated p-cofilin(Ser3) showed redistribution of expression predominantly in the activated form of microglia in PCNs. At pathological level, cofilin-1 expression was significantly altered in cortex and cerebellum in both humans and mice at pre-clinical stage and at early symptomatic clinical stage of the disease. Further, to better understand the possible mechanism of dysregulation of cofilin-1, we also demonstrated alterations in upstream regulators; LIM kinase isoform 1 (LIMK1), slingshot phosphatase isoform 1 (SSH1), RhoA-associated kinase (Rock2), and amyloid precursor protein (APP) in sporadic Creutzfeldt-Jakob disease MM1 mice and in human MM1 and VV2 frontal cortex and cerebellum samples. In conclusion, our findings demonstrated for the first time a key pre-clinical response of cofilin-1 and the associated pathway in prion disease.
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Affiliation(s)
- Saima Zafar
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany.
| | - Neelam Younas
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Nadeem Sheikh
- Department of Zoology, University of the Punjab, Lahore, Pakistan
| | - Waqas Tahir
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Mohsin Shafiq
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Matthias Schmitz
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany
| | - Isidre Ferrer
- Institute of Neuropathology, IDIBELL-University Hospital Bellvitge, University of Barcelona, Hospitalet de Llobregat, Spain.,Network Center for Biomedical Research of Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Ministry of Health, Madrid, Spain
| | - Olivier Andréoletti
- Institut National de la Recherche Agronomique/Ecole Nationale Vétérinaire, Toulouse, France
| | - Inga Zerr
- Department of Neurology, Clinical Dementia Center, and DZNE, Georg-August University, University Medical Center Goettingen (UMG), Robert-Koch-Str. 40, 37075, Goettingen, Germany
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24
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Kage F, Winterhoff M, Dimchev V, Mueller J, Thalheim T, Freise A, Brühmann S, Kollasser J, Block J, Dimchev G, Geyer M, Schnittler HJ, Brakebusch C, Stradal TEB, Carlier MF, Sixt M, Käs J, Faix J, Rottner K. FMNL formins boost lamellipodial force generation. Nat Commun 2017; 8:14832. [PMID: 28327544 PMCID: PMC5364437 DOI: 10.1038/ncomms14832] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/03/2017] [Indexed: 01/16/2023] Open
Abstract
Migration frequently involves Rac-mediated protrusion of lamellipodia, formed by Arp2/3 complex-dependent branching thought to be crucial for force generation and stability of these networks. The formins FMNL2 and FMNL3 are Cdc42 effectors targeting to the lamellipodium tip and shown here to nucleate and elongate actin filaments with complementary activities in vitro. In migrating B16-F1 melanoma cells, both formins contribute to the velocity of lamellipodium protrusion. Loss of FMNL2/3 function in melanoma cells and fibroblasts reduces lamellipodial width, actin filament density and -bundling, without changing patterns of Arp2/3 complex incorporation. Strikingly, in melanoma cells, FMNL2/3 gene inactivation almost completely abolishes protrusion forces exerted by lamellipodia and modifies their ultrastructural organization. Consistently, CRISPR/Cas-mediated depletion of FMNL2/3 in fibroblasts reduces both migration and capability of cells to move against viscous media. Together, we conclude that force generation in lamellipodia strongly depends on FMNL formin activity, operating in addition to Arp2/3 complex-dependent filament branching.
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Affiliation(s)
- Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Moritz Winterhoff
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Vanessa Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jan Mueller
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Tobias Thalheim
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Anika Freise
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Stefan Brühmann
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Jana Kollasser
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark.,Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Jennifer Block
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Matthias Geyer
- Institute of Innate Immunity, Department of Structural Immunology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany
| | - Hans-Joachim Schnittler
- Institute of Anatomy and Vascular Biology, Westfälische Wilhelms-Universität Münster, Vesaliusweg 2-4, 48149 Münster, Germany
| | - Cord Brakebusch
- Biomedical Institute, BRIC, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility Group, Laboratoire d'Enzymologie et Biochimie Structurales, Centre de Recherche de Gif, CNRS, Gif-sur-Yvette 91198, France
| | - Michael Sixt
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Josef Käs
- Soft Matter Physics Group, Institut für experimentelle Physik I, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany.,Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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25
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Dimchev G, Steffen A, Kage F, Dimchev V, Pernier J, Carlier MF, Rottner K. Efficiency of lamellipodia protrusion is determined by the extent of cytosolic actin assembly. Mol Biol Cell 2017; 28:1311-1325. [PMID: 28331069 PMCID: PMC5426846 DOI: 10.1091/mbc.e16-05-0334] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 02/10/2017] [Accepted: 03/17/2017] [Indexed: 11/26/2022] Open
Abstract
Lamellipodia protrusion requires actin network formation driven by the Arp2/3 complex and its upstream regulators WAVE complex and Rac. Actin assembly factors of the formin and Ena/VASP families can influence protrusion, in particular by maintaining a balance between lamellipodial and cytosolic actin filament assembly. Cell migration and cell–cell communication involve the protrusion of actin-rich cell surface projections such as lamellipodia and filopodia. Lamellipodia are networks of actin filaments generated and turned over by filament branching through the Arp2/3 complex. Inhibition of branching is commonly agreed to eliminate formation and maintenance of lamellipodial actin networks, but the regulation of nucleation or elongation of Arp2/3-independent filament populations within the network by, for example, formins or Ena/VASP family members and its influence on the effectiveness of protrusion have been unclear. Here we analyzed the effects of a set of distinct formin fragments and VASP on site-specific, lamellipodial versus cytosolic actin assembly and resulting consequences on protrusion. Surprisingly, expression of formin variants but not VASP reduced lamellipodial protrusion in B16-F1 cells, albeit to variable extents. The rates of actin network polymerization followed a similar trend. Unexpectedly, the degree of inhibition of both parameters depended on the extent of cytosolic but not lamellipodial actin assembly. Indeed, excess cytosolic actin assembly prevented actin monomer from rapid translocation to and efficient incorporation into lamellipodia. Thus, as opposed to sole regulation by actin polymerases operating at their tips, the protrusion efficiency of lamellipodia is determined by a finely tuned balance between lamellipodial and cytosolic actin assembly.
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Affiliation(s)
- Georgi Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Vanessa Dimchev
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany.,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Julien Pernier
- Cytoskeleton Dynamics and Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility, Centre National de la Recherche Scientifique, 91198 Gif-sur-Yvette, France
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, 38106 Braunschweig, Germany .,Department of Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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26
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Kapustina M, Read TA, Vitriol EA. Simultaneous quantification of actin monomer and filament dynamics with modeling-assisted analysis of photoactivation. J Cell Sci 2016; 129:4633-4643. [PMID: 27831495 PMCID: PMC5201019 DOI: 10.1242/jcs.194670] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/02/2016] [Indexed: 01/30/2023] Open
Abstract
Photoactivation allows one to pulse-label molecules and obtain quantitative data about their behavior. We have devised a new modeling-based analysis for photoactivatable actin experiments that simultaneously measures properties of monomeric and filamentous actin in a three-dimensional cellular environment. We use this method to determine differences in the dynamic behavior of β- and γ-actin isoforms, showing that both inhabit filaments that depolymerize at equal rates but that β-actin exists in a higher monomer-to-filament ratio. We also demonstrate that cofilin (cofilin 1) equally accelerates depolymerization of filaments made from both isoforms, but is only required to maintain the β-actin monomer pool. Finally, we used modeling-based analysis to assess actin dynamics in axon-like projections of differentiating neuroblastoma cells, showing that the actin monomer concentration is significantly depleted as the axon develops. Importantly, these results would not have been obtained using traditional half-time analysis. Given that parameters of the publicly available modeling platform can be adjusted to suit the experimental system of the user, this method can easily be used to quantify actin dynamics in many different cell types and subcellular compartments.
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Affiliation(s)
- Maryna Kapustina
- Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Tracy-Ann Read
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
| | - Eric A Vitriol
- Department of Anatomy and Cell Biology, University of Florida, Gainesville, FL 32610, USA
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27
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Isogai T, van der Kammen R, Leyton-Puig D, Kedziora KM, Jalink K, Innocenti M. Initiation of lamellipodia and ruffles involves cooperation between mDia1 and the Arp2/3 complex. J Cell Sci 2015; 128:3796-810. [PMID: 26349808 DOI: 10.1242/jcs.176768] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 09/02/2015] [Indexed: 01/20/2023] Open
Abstract
Protrusion of lamellipodia and ruffles requires polymerization of branched actin filaments by the Arp2/3 complex. Although regulation of Arp2/3 complex activity has been extensively investigated, the mechanism of initiation of lamellipodia and ruffles remains poorly understood. Here, we show that mDia1 acts in concert with the Arp2/3 complex to promote initiation of lamellipodia and ruffles. We find that mDia1 is an epidermal growth factor (EGF)-regulated actin nucleator involved in membrane ruffling using a combination of knockdown and rescue experiments. At the molecular level, mDia1 polymerizes linear actin filaments, activating the Arp2/3 complex, and localizes within nascent and mature membrane ruffles. We employ functional complementation experiments and optogenetics to show that mDia1 cooperates with the Arp2/3 complex in initiating lamellipodia and ruffles. Finally, we show that genetic and pharmacological interference with this cooperation hampers ruffling and cell migration. Thus, we propose that the lamellipodium- and ruffle-initiating machinery consists of two actin nucleators that act sequentially to regulate membrane protrusion and cell migration.
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Affiliation(s)
- Tadamoto Isogai
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
| | - Rob van der Kammen
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
| | - Daniela Leyton-Puig
- Division of Cell Biology I, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
| | - Katarzyna M Kedziora
- Division of Cell Biology I, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
| | - Kees Jalink
- Division of Cell Biology I, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
| | - Metello Innocenti
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam 1066 CX, The Netherlands
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28
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Chronophin coordinates cell leading edge dynamics by controlling active cofilin levels. Proc Natl Acad Sci U S A 2015; 112:E5150-9. [PMID: 26324884 DOI: 10.1073/pnas.1510945112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cofilin, a critical player of actin dynamics, is spatially and temporally regulated to control the direction and force of membrane extension required for cell locomotion. In carcinoma cells, although the signaling pathways regulating cofilin activity to control cell direction have been established, the molecular machinery required to generate the force of the protrusion remains unclear. We show that the cofilin phosphatase chronophin (CIN) spatiotemporally regulates cofilin activity at the cell edge to generate persistent membrane extension. We show that CIN translocates to the leading edge in a PI3-kinase-, Rac1-, and cofilin-dependent manner after EGF stimulation to activate cofilin, promotes actin free barbed end formation, accelerates actin turnover, and enhances membrane protrusion. In addition, we establish that CIN is crucial for the balance of protrusion/retraction events during cell migration. Thus, CIN coordinates the leading edge dynamics by controlling active cofilin levels to promote MTLn3 cell protrusion.
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29
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Decreased CXCL12 is associated with impaired alveolar epithelial cell migration and poor lung healing after lung resection. Surgery 2015. [PMID: 26212341 DOI: 10.1016/j.surg.2015.04.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Prolonged air leak (PAL) is an important cause of morbidity and mortality after lung resection, but its pathogenesis has not been elucidated. Migration of alveolar type II epithelial cells is essential for lung wound repair. Here we determined the role of C-X-C motif chemokine 12 (CXCL12) on alveolar epithelial cell migration and lung wound healing. METHODS CXCL12 in the pleural fluid of patients was analyzed using enzyme-linked immunosorbent assay. Human A549 and murine MLE12 alveolar epithelial cell lines were used for wound closure, cell migration, and proliferation assays. Western blot was used to analyze Rac1 and cofilin. RESULTS Pleural CXCL12 was decreased in patients with PAL (1,389 ± 192 vs 3,270 ± 247 pg/mL; P < .0001). CXCL12 enhanced scratch wound closure in both A549 (77.9 ± 0.7% vs 71.5 ± 0.4%; P = .0016) and MLE12 (92.9 ± 4.9% vs 66.0 ± 4.8%; P = .017). CXCL12 enhanced migration by 57% in A549 (P = .0008) and by 86% in MLE12 (P < .0001). AMD3100, a selective CXCR4 antagonist, prevented the effects of CXCL12. CXCL12 increased Rac1 and cofilin activation but did not change bromodeoxyuridine incorporation or cell counts. CONCLUSION Reduced pleural CXCL12 is associated with PAL. CXCL12 promotes alveolar epithelial cell migration by binding to its receptor CXCR4 and may have a role in lung healing. CXCL12-mediated alveolar epithelial cell migration is associated with Rac1 and cofilin activation.
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30
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Cameron JM, Gabrielsen M, Chim YH, Munro J, McGhee EJ, Sumpton D, Eaton P, Anderson KI, Yin H, Olson MF. Polarized cell motility induces hydrogen peroxide to inhibit cofilin via cysteine oxidation. Curr Biol 2015; 25:1520-5. [PMID: 25981793 PMCID: PMC4454775 DOI: 10.1016/j.cub.2015.04.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/10/2015] [Accepted: 04/13/2015] [Indexed: 12/04/2022]
Abstract
Mesenchymal cell motility is driven by polarized actin polymerization [1]. Signals at the leading edge recruit actin polymerization machinery to promote membrane protrusion, while matrix adhesion generates tractive force to propel forward movement. To work effectively, cell motility is regulated by a complex network of signaling events that affect protein activity and localization. H2O2 has an important role as a diffusible second messenger [2], and mediates its effects through oxidation of cysteine thiols. One cell activity influenced by H2O2 is motility [3]. However, a lack of sensitive and H2O2-specific probes for measurements in live cells has not allowed for direct observation of H2O2 accumulation in migrating cells or protrusions. In addition, the identities of proteins oxidized by H2O2 that contribute to actin dynamics and cell motility have not been characterized. We now show, as determined by fluorescence lifetime imaging microscopy, that motile cells generate H2O2 at membranes and cell protrusions and that H2O2 inhibits cofilin activity through oxidation of cysteines 139 (C139) and 147 (C147). Molecular modeling suggests that C139 oxidation would sterically hinder actin association, while the increased negative charge of oxidized C147 would lead to electrostatic repulsion of the opposite negatively charged surface. Expression of oxidation-resistant cofilin impairs cell spreading, adhesion, and directional migration. These findings indicate that H2O2 production contributes to polarized cell motility through localized cofilin inhibition and that there are additional proteins oxidized during cell migration that might have similar roles.
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Affiliation(s)
- Jenifer M Cameron
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Mads Gabrielsen
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Ya Hua Chim
- Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow G12 8LT, UK
| | - June Munro
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Ewan J McGhee
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - David Sumpton
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Philip Eaton
- Cardiovascular Division, The Rayne Institute, St. Thomas' Hospital, King's College London, London SE1 7EH, UK
| | - Kurt I Anderson
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK
| | - Huabing Yin
- Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow G12 8LT, UK
| | - Michael F Olson
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Road, Glasgow G61 1BD, UK.
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31
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Jansen S, Collins A, Chin SM, Ydenberg CA, Gelles J, Goode BL. Single-molecule imaging of a three-component ordered actin disassembly mechanism. Nat Commun 2015; 6:7202. [PMID: 25995115 PMCID: PMC4443854 DOI: 10.1038/ncomms8202] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 04/17/2015] [Indexed: 12/25/2022] Open
Abstract
The mechanisms by which cells destabilize and rapidly disassemble filamentous actin networks have remained elusive; however, Coronin, Cofilin and AIP1 have been implicated in this process. Here using multi-wavelength single-molecule fluorescence imaging, we show that mammalian Cor1B, Cof1 and AIP1 work in concert through a temporally ordered pathway to induce highly efficient severing and disassembly of actin filaments. Cor1B binds to filaments first, and dramatically accelerates the subsequent binding of Cof1, leading to heavily decorated, stabilized filaments. Cof1 in turn recruits AIP1, which rapidly triggers severing and remains bound to the newly generated barbed ends. New growth at barbed ends generated by severing was blocked specifically in the presence of all three proteins. This activity enabled us to reconstitute and directly visualize single actin filaments being rapidly polymerized by formins at their barbed ends while simultanteously being stochastically severed and capped along their lengths, and disassembled from their pointed ends. The roles of Coronin, Cofilin and AIP1 in promoting actin disassembly have not been well understood. Here using single-molecule fluorescence imaging, Jansen et al. show that the three proteins act together in a coordinated, temporal pathway to induce rapid severing and disassembly of actin filaments.
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Affiliation(s)
- Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Agnieszka Collins
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Samantha M Chin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Casey A Ydenberg
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Jeff Gelles
- Department of Biochemistry, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, 415 South street, Waltham, Massachusetts 02454, USA
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32
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Vitriol EA, McMillen LM, Kapustina M, Gomez SM, Vavylonis D, Zheng JQ. Two functionally distinct sources of actin monomers supply the leading edge of lamellipodia. Cell Rep 2015. [PMID: 25865895 DOI: 10.1016/j.celrep.2015.03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Lamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two functionally and molecularly distinct sources of G-actin that supply lamellipodial actin networks. G-actin originating from the cytosolic pool requires the monomer-binding protein thymosin β4 (Tβ4) for optimal leading-edge localization, is targeted to formins, and is responsible for creating an elevated G/F-actin ratio that promotes membrane protrusion. The second source of G-actin comes from recycled lamellipodia F-actin. Recycling occurs independently of Tβ4 and appears to regulate lamellipodia homeostasis. Tβ4-bound G-actin specifically localizes to the leading edge because it does not interact with Arp2/3-mediated polymerization sites found throughout the lamellipodia. These findings demonstrate that actin networks can be constructed from multiple sources of monomers with discrete spatiotemporal functions.
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Affiliation(s)
- Eric A Vitriol
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Laura M McMillen
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
| | - Maryna Kapustina
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shawn M Gomez
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - James Q Zheng
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA 30322, USA.
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33
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Vitriol EA, McMillen LM, Kapustina M, Gomez SM, Vavylonis D, Zheng JQ. Two functionally distinct sources of actin monomers supply the leading edge of lamellipodia. Cell Rep 2015; 11:433-45. [PMID: 25865895 DOI: 10.1016/j.celrep.2015.03.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 11/20/2014] [Accepted: 03/13/2015] [Indexed: 12/21/2022] Open
Abstract
Lamellipodia, the sheet-like protrusions of motile cells, consist of networks of actin filaments (F-actin) regulated by the ordered assembly from and disassembly into actin monomers (G-actin). Traditionally, G-actin is thought to exist as a homogeneous pool. Here, we show that there are two functionally and molecularly distinct sources of G-actin that supply lamellipodial actin networks. G-actin originating from the cytosolic pool requires the monomer-binding protein thymosin β4 (Tβ4) for optimal leading-edge localization, is targeted to formins, and is responsible for creating an elevated G/F-actin ratio that promotes membrane protrusion. The second source of G-actin comes from recycled lamellipodia F-actin. Recycling occurs independently of Tβ4 and appears to regulate lamellipodia homeostasis. Tβ4-bound G-actin specifically localizes to the leading edge because it does not interact with Arp2/3-mediated polymerization sites found throughout the lamellipodia. These findings demonstrate that actin networks can be constructed from multiple sources of monomers with discrete spatiotemporal functions.
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Affiliation(s)
- Eric A Vitriol
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Laura M McMillen
- Department of Physics, Lehigh University, Bethlehem, PA 18015, USA
| | - Maryna Kapustina
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Shawn M Gomez
- Department of Computer Science, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | - James Q Zheng
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Zheng K, Kitazato K, Wang Y, He Z. Pathogenic microbes manipulate cofilin activity to subvert actin cytoskeleton. Crit Rev Microbiol 2015; 42:677-95. [PMID: 25853495 DOI: 10.3109/1040841x.2015.1010139] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Actin-depolymerizing factor (ADF)/cofilin proteins are key players in controlling the temporal and spatial extent of actin dynamics, which is crucial for mediating host-pathogen interactions. Pathogenic microbes have evolved molecular mechanisms to manipulate cofilin activity to subvert the actin cytoskeletal system in host cells, promoting their internalization into the target cells, modifying the replication niche and facilitating their intracellular and intercellular dissemination. The study of how these pathogens exploit cofilin pathways is crucial for understanding infectious disease and providing potential targets for drug therapies.
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Affiliation(s)
- Kai Zheng
- a Department of Pharmacy, School of Medicine , Shenzhen University , Shenzhen , Guangdong , People's Republic of China .,c Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University , Guangzhou , China
| | - Kaio Kitazato
- b Division of Molecular Pharmacology of Infectious Agents, Department of Molecular Microbiology and Immunology , Nagasaki University , Nagasaki , Japan , and
| | - Yifei Wang
- c Guangzhou Jinan Biomedicine Research and Development Center, National Engineering Research Center of Genetic Medicine, Jinan University , Guangzhou , China
| | - Zhendan He
- a Department of Pharmacy, School of Medicine , Shenzhen University , Shenzhen , Guangdong , People's Republic of China
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Sano Y, Watanabe W, Matsunaga S. Chromophore-assisted laser inactivation--towards a spatiotemporal-functional analysis of proteins, and the ablation of chromatin, organelle and cell function. J Cell Sci 2014; 127:1621-9. [PMID: 24737873 DOI: 10.1242/jcs.144527] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chromophore-assisted laser or light inactivation (CALI) has been employed as a promising technique to achieve spatiotemporal knockdown or loss-of-function of target molecules in situ. CALI is performed using photosensitizers as generators of reactive oxygen species (ROS). There are two CALI approaches that use either transgenic tags with chemical photosensitizers, or genetically encoded fluorescent protein fusions. Using spatially restricted microscopy illumination, CALI can address questions regarding, for example, protein isoforms, subcellular localization or phase-specific analyses of multifunctional proteins that other knockdown approaches, such as RNA interference or treatment with chemicals, cannot. Furthermore, rescue experiments can clarify the phenotypic capabilities of CALI after the depletion of endogenous targets. CALI can also provide information about individual events that are involved in the function of a target protein and highlight them in multifactorial events. Beyond functional analysis of proteins, CALI of nuclear proteins can be performed to induce cell cycle arrest, chromatin- or locus-specific DNA damage. Even at organelle level - such as in mitochondria, the plasma membrane or lysosomes - CALI can trigger cell death. Moreover, CALI has emerged as an optogenetic tool to switch off signaling pathways, including the optical depletion of individual neurons. In this Commentary, we review recent applications of CALI and discuss the utility and effective use of CALI to address open questions in cell biology.
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Affiliation(s)
- Yukimi Sano
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
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Hughes RM, Lawrence DS. Optogenetic engineering: light-directed cell motility. Angew Chem Int Ed Engl 2014; 53:10904-7. [PMID: 25156888 PMCID: PMC4196877 DOI: 10.1002/anie.201404198] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 07/25/2014] [Indexed: 11/10/2022]
Abstract
Genetically encoded, light-activatable proteins provide the means to probe biochemical pathways at specific subcellular locations with exquisite temporal control. However, engineering these systems in order to provide a dramatic jump in localized activity, while retaining a low dark-state background remains a significant challenge. When placed within the framework of a genetically encodable, light-activatable heterodimerizer system, the actin-remodelling protein cofilin induces dramatic changes in the F-actin network and consequent cell motility upon illumination. We demonstrate that the use of a partially impaired mutant of cofilin is critical for maintaining low background activity in the dark. We also show that light-directed recruitment of the reduced activity cofilin mutants to the cytoskeleton is sufficient to induce F-actin remodeling, formation of filopodia, and directed cell motility.
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Affiliation(s)
- Robert M. Hughes
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, and Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599 (USA)
| | - David S. Lawrence
- Department of Chemistry, Division of Chemical Biology and Medicinal Chemistry, and Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599 (USA)
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37
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Hughes RM, Lawrence DS. Optogenetic Engineering: Light-Directed Cell Motility. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Abstract
Structured illumination microscopy (SIM) with a 3-dimensional illumination pattern allows to double image resolution laterally and axially. For cell biologists, SIM may become an attractive tool for refined colocalization studies and to investigate the assembly of components at higher resolution. In this chapter, we focus on the use of a commercial available SIM setup and provide guidance on sample preparation and image acquisition. We present superresolution images of the cytoskeleton in fixed cells and discuss the potential and limitations for SIM in live imaging.
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Affiliation(s)
- Ulrike Engel
- Center for Organismal Studies and Nikon Imaging Center, Bioquant, University of Heidelberg, Heidelberg, Germany
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