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Voronkina A, Cárdenas P, Adam J, Meissner H, Nowacki K, Joseph Y, Tabachnick KR, Ehrlich H. Biosilica 3D Micromorphology of Geodiidae Sponge Spicules Is Patterned by F-Actin. Microsc Res Tech 2025; 88:1701-1711. [PMID: 39894974 DOI: 10.1002/jemt.24798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 12/26/2024] [Accepted: 12/28/2024] [Indexed: 02/04/2025]
Abstract
Demosponges (phylum Porifera) are among the first multicellular organisms on the planet and represent a unique archive of biosilica-based skeletal structures with species-specific microstructures called spicules. With more than 80 morphotypes, this class of sponges is recognized as a unique source of amorphous silica with superficial ornamentation patterned by organic phases. In this study, we investigated spicules of selected representatives of the family Geodiidae (order Tetractinellida), to identify F-actin-containing axial filaments within these 3D skeletal microconstructs defined as oxyspherasters and sterrasters. Their desilicification using 10% HF leads to isolation of multifilamentous, radially oriented organic matrices, which resemble the shape and size of the original spicules. Our data show that highly specific indicators of F-actin such as iFluorTM 594-Phalloidin, iFluorTM 488-Phalloidin, as well as iFluorTM 350-Phalloidin unambiguously confirm its localization within demineralized oxyspherasters and sterrasters of 11 diverse demosponges species belonging to the subfamily Geodiinae (genera Geodia, Rhabdastrella) and the subfamily Erylinae (genera Caminella, Caminus, Erylus, Pachymatisma). Well-defined periodicity in Geodia cydonium sterrasters actin filaments has been observed using atomic force microscopy (AFM) for the first time. The findings of F-actin as a possible pattern driver in spicules of geodiids brings additional light to our knowledge of spiculogenesis in this group. However, no specific actin structures were found between the geodiid subfamilies or genera thereby suggesting a common actin process, present already at the emergence of the family (~170 million years ago).
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Affiliation(s)
- Alona Voronkina
- Pharmacy Department, National Pirogov Memorial Medical University, Vinnytsia, Ukraine
- Institute for Nanoscale and Biobased Materials, TU Bergakademie Freiberg, Freiberg, Germany
| | - Paco Cárdenas
- Pharmacognosy, Department of Pharmaceutical Biosciences, Museum of Evolution, Uppsala University, Uppsala, Sweden
| | - Jörg Adam
- Institute for Nanoscale and Biobased Materials, TU Bergakademie Freiberg, Freiberg, Germany
| | - Heike Meissner
- Department of Prosthetic Dentistry, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Krzysztof Nowacki
- Institute of Chemistry and Technical Electrochemistry, Poznan University of Technology, Poznan, Poland
| | - Yvonne Joseph
- Institute for Nanoscale and Biobased Materials, TU Bergakademie Freiberg, Freiberg, Germany
| | | | - Hermann Ehrlich
- Center for Advanced Technology, Adam Mickiewicz University in Poznan, Poznan, Poland
- Institute of Chemical Technology, Faculty of Chemical Technology, Poznan University of Technology, Poznan, Poland
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Wang J, Su X, Jia Z, Peng W, Dou L, Mao P. Genome-wide characterization and expression profiling of FIMBRIN gene family members in response to abiotic stress in Medicago sativa. BMC PLANT BIOLOGY 2025; 25:575. [PMID: 40316946 PMCID: PMC12049050 DOI: 10.1186/s12870-025-06616-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2025] [Accepted: 04/24/2025] [Indexed: 05/04/2025]
Abstract
BACKGROUND Alfalfa is widely regarded as one of the most important forage crops globally. However, its growth and development are primarily constrained by various abiotic stresses. FIMBRINs are crucial actin-binding proteins involved in regulating cellular dynamics in plants under various stress conditions and during developmental processes. The Fimbrin (FIM) gene family has been reported only in Arabidopsis, while a comprehensive identification of the FIM gene family in alfalfa and the responses of its members to abiotic stresses remain unclear. RESULTS In this study, six MsFIM genes were identified in the alfalfa genome, distributed across three chromosomes. Phylogenetic analysis grouped these genes into four clades, all containing the conserved CH domain. Gene duplication events suggested that large fragment duplications contribute to gene amplification. Furthermore, cis-regulatory element analysis highlighted their pivotal roles in plant development and response to external abiotic stresses. RT-qPCR analyses revealed that the MsFIM genes exhibited differential expression across various tissues, with predominant expression in flowers, stems, and leaves. The MsFIM genes showed elevated expression under abiotic stresses (drought, cold, and salt) as well as hormone treatment (abscisic acid, ABA), suggesting that they served as positive regulators in alfalfa's resistance to abiotic stresses and its growth and development. CONCLUSIONS This study investigates the MsFIM genes in alfalfa, further analyzing their potential roles in plant development and response to abiotic stresses. These findings will provide novel insights into the molecular mechanisms of alfalfa's stress response.
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Affiliation(s)
- Juan Wang
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Xinru Su
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Zhicheng Jia
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Wenxin Peng
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China
| | - Liru Dou
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China.
| | - Peisheng Mao
- College of Grassland Science and Technology, China Agricultural University, Beijing, 100193, China.
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Schallmoser A, Emrich N, Einenkel R, Sänger N. Explorative 3-D culture of early secondary follicles in a time lapse system for up to 36 days gives valuable, but limited insights in follicular development. Placenta 2025; 164:50-63. [PMID: 40127611 DOI: 10.1016/j.placenta.2025.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Revised: 02/10/2025] [Accepted: 03/10/2025] [Indexed: 03/26/2025]
Abstract
BACKGROUND Cryopreservation of ovarian cortical tissue is an important option for female fertility preservation. This is particularly valuable for cancer patients who need to be treated urgently with chemotherapy, leaving no time for hormonal stimulation. The transfer of malignant cells in certain cancers remains as a potential risk after freezing, thawing and transplantation of ovarian tissue while isolation and in vitro growth (IVG) of follicles could be a safe alternate approach of female fertility protection. METHODS Ovarian cortex tissue was frozen, thawed and cultured for 8 days prior to isolating and embedding of early secondary follicles in a 3D matrix, suitable for time lapse monitoring for up to 36 days. Continuous growth of a theca-like cell layer and extrafollicular protrusions were visually evaluated with a permanent monitoring system facilitating real-time follicular development without deviations in the culture conditions. Occurrence of theca cell growth was visually characterized by extrafollicular formation of cells, beyond the outer follicle boundaries. To validate the results observed by time-lapse monitoring, live cell imaging was conducted and determined with immunofluorescence staining. RESULTS Individual follicles significantly increased in size over time. Time-lapse video monitoring revealed extending and retracting of filopodia-like structures in the outer follicular region adjacent to the 3D environment. Theca-like cells and actin components of filopodia-like structures were identified based on immunofluorescence staining. CONCLUSIONS Time lapse monitoring of 3-D cultured follicles is a promising explorative approach to obtain valuable visual insights regarding the many facets of follicular growth and to optimize follicular culture conditions towards a clinical application. As the study is limited by a lack of mechanistic insights into theca cell differentiation and filopodia function, additional studies are necessary to validate the preliminary results of this approach.
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Affiliation(s)
- Andreas Schallmoser
- Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital of Bonn, Germany.
| | - Norah Emrich
- Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital of Bonn, Germany
| | - Rebekka Einenkel
- Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital of Bonn, Germany.
| | - Nicole Sänger
- Department of Gynecological Endocrinology and Reproductive Medicine, University Hospital of Bonn, Germany.
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Martins CS, Iv F, Suman SK, Panagiotou TC, Sidor C, Ruso-López M, Plancke CN, Omi S, Pagès R, Gomes M, Llewellyn A, Bandi SR, Ramond L, Arbizzani F, Rimoli CV, Schnorrer F, Robin F, Wilde A, LeGoff L, Pedelacq JD, Jégou A, Cabantous S, Rincon SA, Chandre C, Brasselet S, Mavrakis M. Genetically encoded reporters of actin filament organization in living cells and tissues. Cell 2025; 188:2540-2559.e27. [PMID: 40179884 DOI: 10.1016/j.cell.2025.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 12/09/2024] [Accepted: 03/03/2025] [Indexed: 04/05/2025]
Abstract
The cytoskeletal protein actin is crucial for cell shape and integrity throughout eukaryotes. Actin filaments perform essential biological functions, including muscle contraction, cell division, and tissue morphogenesis. These diverse activities are achieved through the ability of actin filaments to be arranged into precise architectures. Much progress has been made in defining the proteome of the actin cytoskeleton, but a detailed appreciation of the dynamic organizational state of the actin filaments themselves has been hindered by available tools. Fluorescence polarization microscopy is uniquely placed for measuring actin filament organization by exploiting the sensitivity of polarized light excitation to the orientation of fluorophores attached to actin filaments. By engineering fusions of five widely used actin localization reporters to fluorescent proteins with constrained mobility, we have succeeded in developing genetically encoded, green- and red-fluorescent-protein-based reporters for non-invasive, quantitative measurements of actin filament organization in living cells and tissues by fluorescence polarization microscopy.
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Affiliation(s)
- Carla Silva Martins
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - François Iv
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Shashi Kumar Suman
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, Laboratoire de Biologie du Développement/UMR7622, 75005 Paris, France
| | - Thomas C Panagiotou
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1M1, Canada
| | - Clara Sidor
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, 13009 Marseille, France
| | - María Ruso-López
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, Salamanca 37007, Spain
| | - Camille N Plancke
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, Laboratoire de Biologie du Développement/UMR7622, 75005 Paris, France
| | - Shizue Omi
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Rebecca Pagès
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Maxime Gomes
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Alexander Llewellyn
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Sourish Reddy Bandi
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Laurie Ramond
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | | | - Caio Vaz Rimoli
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Frank Schnorrer
- Aix Marseille Univ, CNRS, IBDM, Turing Centre for Living Systems, 13009 Marseille, France
| | - François Robin
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, Laboratoire de Biologie du Développement/UMR7622, 75005 Paris, France
| | - Andrew Wilde
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1M1, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5S 1M1, Canada
| | - Loïc LeGoff
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France
| | - Jean-Denis Pedelacq
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Antoine Jégou
- Université Paris Cité, CNRS, Institut Jacques Monod, Paris, France
| | - Stéphanie Cabantous
- Centre de Recherche en Cancérologie de Toulouse (CRCT), Inserm, Université Paul Sabatier - Toulouse III, CNRS, 31037 Toulouse, France
| | - Sergio A Rincon
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, Consejo Superior de Investigaciones Científicas (CSIC)/Universidad de Salamanca, Salamanca 37007, Spain
| | | | - Sophie Brasselet
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France.
| | - Manos Mavrakis
- Institut Fresnel, CNRS UMR7249, Aix Marseille Univ, Centrale Med, 13013 Marseille, France.
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Sun D, Zhao X, Wiegand T, Martin-Lemaitre C, Borianne T, Kleinschmidt L, Grill SW, Hyman AA, Weber C, Honigmann A. Assembly of tight junction belts by ZO1 surface condensation and local actin polymerization. Dev Cell 2025; 60:1234-1250.e6. [PMID: 39742662 DOI: 10.1016/j.devcel.2024.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 09/30/2024] [Accepted: 12/05/2024] [Indexed: 01/04/2025]
Abstract
Tight junctions play an essential role in sealing tissues, by forming belts of adhesion strands around cellular perimeters. Recent work has shown that the condensation of ZO1 scaffold proteins is required for tight junction assembly. However, the mechanisms by which junctional condensates initiate at cell-cell contacts and elongate around cell perimeters remain unknown. Combining biochemical reconstitutions and live-cell imaging of MDCKII tissue, we found that tight junction belt formation is driven by adhesion receptor-mediated ZO1 surface condensation coupled to local actin polymerization. Adhesion receptor oligomerization provides the signal for surface binding and local condensation of ZO1 at the cell membrane. Condensation produces a molecular scaffold that selectively enriches junctional proteins. Finally, ZO1 condensates directly facilitate local actin polymerization and filament bundling, driving the elongation into a continuous tight junction belt. More broadly, our work identifies how cells couple surface condensation with cytoskeleton organization to assemble and structure adhesion complexes.
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Affiliation(s)
- Daxiao Sun
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Technische Universität Dresden, Biotechnologisches Zentrum, Center for Molecular and Cellular Bioengineering (CMCB), Dresden, Germany.
| | - Xueping Zhao
- Department of Mathematical Sciences, University of Nottingham, Ningbo, China
| | - Tina Wiegand
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Cecilie Martin-Lemaitre
- Technische Universität Dresden, Biotechnologisches Zentrum, Center for Molecular and Cellular Bioengineering (CMCB), Dresden, Germany
| | - Tom Borianne
- Technische Universität Dresden, Biotechnologisches Zentrum, Center for Molecular and Cellular Bioengineering (CMCB), Dresden, Germany
| | - Lennart Kleinschmidt
- Technische Universität Dresden, Biotechnologisches Zentrum, Center for Molecular and Cellular Bioengineering (CMCB), Dresden, Germany
| | - Stephan W Grill
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
| | - Anthony A Hyman
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
| | - Christoph Weber
- Faculty of Mathematics, Natural Sciences, and Materials Engineering, Institute of Physics, University of Augsburg, Augsburg, Germany.
| | - Alf Honigmann
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany; Technische Universität Dresden, Biotechnologisches Zentrum, Center for Molecular and Cellular Bioengineering (CMCB), Dresden, Germany; Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany.
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6
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Shatskiy D, Sivan A, Wedlich-Söldner R, Belyy A. Structure of the F-tractin-F-actin complex. J Cell Biol 2025; 224:e202409192. [PMID: 39928047 PMCID: PMC11809415 DOI: 10.1083/jcb.202409192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2024] [Revised: 12/19/2024] [Accepted: 01/28/2025] [Indexed: 02/11/2025] Open
Abstract
F-tractin is a peptide widely used to visualize the actin cytoskeleton in live eukaryotic cells but has been reported to impair cell migration and induce actin bundling at high expression levels. To elucidate these effects, we determined the cryo-EM structure of the F-tractin-F-actin complex, revealing that F-tractin consists of a flexible N-terminal region and an amphipathic C-terminal helix. The N-terminal part is dispensable for F-actin binding but responsible for the bundling effect. Based on these insights, we developed an optimized F-tractin, which eliminates the N-terminal region and minimizes bundling while retaining strong actin labeling. The C-terminal helix interacts with a hydrophobic pocket formed by two neighboring actin subunits, an interaction region shared by many actin-binding polypeptides, including the popular actin-binding probe Lifeact. Thus, rather than contrasting F-tractin and Lifeact, our data indicate that these peptides have analogous modes of interaction with F-actin. Our study dissects the structural elements of F-tractin and provides a foundation for developing future actin probes.
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Affiliation(s)
- Dmitry Shatskiy
- Membrane Enzymology Group, Groningen Institute of Biomolecular Sciences and Biotechnology (GBB), Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
| | - Athul Sivan
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Alexander Belyy
- Membrane Enzymology Group, Groningen Institute of Biomolecular Sciences and Biotechnology (GBB), Faculty of Science and Engineering, University of Groningen, Groningen, The Netherlands
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7
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Amita H, Subair Z, Mora T, Dudhe PE, Dhanasekaran K. Betrayal From the Core: Centriolar and Cytoskeletal Subversion by Infectious Pathogens. Cytoskeleton (Hoboken) 2025. [PMID: 39902598 DOI: 10.1002/cm.22004] [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: 10/14/2024] [Revised: 12/30/2024] [Accepted: 01/24/2025] [Indexed: 02/05/2025]
Abstract
Microbes and parasites have evolved several means to evade and usurp the host cellular machinery to mediate pathogenesis. Being the major microtubule-organizing center (MTOC) of the cell, the centrosome is targeted by multiple viral and nonviral pathogens to mediate their assembly and trafficking within the host cell. This review examines the consequence of such targeting to the centrosome and associated cytoskeletal machinery. We have also amassed a substantial body of evidence of viruses utilizing the cilia within airway epithelium to mediate infection and the hijacking of host cytoskeletal machinery for efficient entry, replication, and egress. While infections have been demonstrated to induce structural, functional, and numerical aberrations in centrosomes, and induce ciliary dysfunction, current literature increasingly supports the notion of a pro-viral role for these organelles. Although less explored, the impact of bacterial and parasitic pathogens on these structures has also been addressed very briefly. Mechanistically, the molecular pathways responsible for these effects remain largely uncharacterized in many instances. Future research focusing on the centriolar triad comprising the centrosome, cilia, and centriolar satellites will undoubtedly provide vital insights into the tactics employed by infectious agents to subvert the host centriole and cytoskeleton-based machinery.
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Affiliation(s)
- Himanshi Amita
- Laboratory of Centrosome and Cilia Biology, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Zidhan Subair
- Laboratory of Centrosome and Cilia Biology, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Tulasiram Mora
- Laboratory of Centrosome and Cilia Biology, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Pranay Eknath Dudhe
- Laboratory of Centrosome and Cilia Biology, Regional Centre for Biotechnology, Faridabad, Haryana, India
| | - Karthigeyan Dhanasekaran
- Laboratory of Centrosome and Cilia Biology, Regional Centre for Biotechnology, Faridabad, Haryana, India
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8
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Keller KE, Kaech Petrie S. Nanotubules and Cellular Communication in Trabecular Meshwork Cells. Methods Mol Biol 2025; 2858:49-62. [PMID: 39433666 DOI: 10.1007/978-1-0716-4140-8_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2024]
Abstract
Glaucoma causes dysfunction to tissues located in the anterior and posterior eye. In the anterior eye, the trabecular meshwork (TM) is the site of pathogenesis, where decreased TM cell numbers and alterations to the amount and composition of extracellular matrix hinder outflow of aqueous humor fluid from the anterior chamber. This causes intraocular pressure (IOP) elevation. Elevated IOP, a main risk factor for primary open-angle glaucoma, damages the axons of retinal ganglion cells in the posterior eye, which ultimately leads to blindness. Thus, clinical treatment paradigms for glaucoma are focused on reducing IOP. Normotensive IOPs are established by balancing the production of aqueous fluid from the ciliary body with drainage through the TM to Schlemm's canal. When IOP becomes elevated, TM cells coordinate a homeostatic response to lower IOP, which requires effective and efficient cellular communication. Tunneling nanotubes (TNTs) are transient specialized structures that allow cells to communicate with one another. Actin-rich tubes allow direct transmission of signals and cargoes between cells. This is important to overcome limitations of diffusion-based signaling in aqueous environments such as the anterior eye. Here, we describe a live-cell imaging method for monitoring TNTs in primary TM cells.
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Affiliation(s)
- Kate E Keller
- Department of Ophthalmology, Oregon Health & Science University, Portland, OR, USA.
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Taniguchi S, Torii T, Goto T, Takeuchi K, Katsumi R, Sumida M, Lee S, Sugimoto W, Gessho M, Itoh K, Hirata H, Kawakami J, Miyoshi D, Kawauchi K. Bioinformatic Analysis of Actin-Binding Proteins in the Nucleolus During Heat Shock. Genes (Basel) 2024; 15:1580. [PMID: 39766847 PMCID: PMC11675300 DOI: 10.3390/genes15121580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2024] [Revised: 12/02/2024] [Accepted: 12/03/2024] [Indexed: 01/11/2025] Open
Abstract
BACKGROUND/OBJECTIVES Actin plays a crucial role not only in the cytoplasm, but also in the nucleus, influencing various cellular behaviors, including cell migration and gene expression. Recent studies reveal that nuclear actin dynamics is altered by cellular stresses, such as DNA damage; however, the effect of heat shock on nuclear actin dynamics, particularly in the nucleolus, remains unclear. This study aims to elucidate the contribution of nucleolar actin to cellular responses under heat shock conditions. METHODS Nuclear actin dynamics in response to heat shock were investigated using nAC-GFP, a GFP-tagged actin chromobody, to visualize nuclear actin in HeLa cells. Bioinformatic analyses were also performed. RESULTS Heat shock induced the reversible assembly of nAC-GFP in the nucleolus, with disassembly occurring upon recovery in a heat shock protein (Hsp) 70-dependent manner. Because the nucleolus, formed via liquid-liquid phase separation (LLPS), sequesters misfolded proteins under heat shock to prevent irreversible aggregation, we hypothesized that nucleolar actin-binding proteins might also be sequestered in a similar manner. Using several databases, we identified 47 actin-binding proteins localized in the nucleolus and determined the proportion of intrinsically disordered regions (IDRs) known to promote LLPS. Our analysis revealed that many of these 47 proteins exhibited high levels of IDRs. CONCLUSIONS The findings from our bioinformatics analysis and further cellular studies may help elucidate new roles for actin in the heat shock response.
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Affiliation(s)
- Shinya Taniguchi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Takeru Torii
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Toshiyuki Goto
- Graduate School of Science, Technology and Innovation, Kobe University, Kobe 650-0047, Japan;
| | - Kohei Takeuchi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Rine Katsumi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Mako Sumida
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Sunmin Lee
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Wataru Sugimoto
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Masaya Gessho
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Katsuhiko Itoh
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Hiroaki Hirata
- Department of Applied Bioscience, Kanazawa Institute of Technology, Hakusan 924-0838, Japan;
| | - Junji Kawakami
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Daisuke Miyoshi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
| | - Keiko Kawauchi
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe 650-0047, Japan; (S.T.); (T.T.); (K.T.); (R.K.); (M.S.); (S.L.); (W.S.); (M.G.); (K.I.); (J.K.); (D.M.)
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10
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Hollander S, Guo Y, Wolfenson H, Zaritsky A. Spatiotemporal analysis of F-actin polymerization with micropillar arrays reveals synchronization between adhesion sites. Mol Biol Cell 2024; 35:br23. [PMID: 39441710 PMCID: PMC11656478 DOI: 10.1091/mbc.e24-06-0276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 10/15/2024] [Accepted: 10/16/2024] [Indexed: 10/25/2024] Open
Abstract
We repurposed micropillar arrays to quantify spatiotemporal inter-adhesion communication. Following the observation that integrin adhesions formed around pillar tops we relied on the precise repetitive spatial control of the pillars to reliably monitor F-actin dynamics in mouse embryonic fibroblasts as a model for spatiotemporal adhesion-related intracellular signaling. Using correlation-based analyses, we revealed localized information flows propagating between adjacent pillars that were integrated over space and time to synchronize the adhesion dynamics within the entire cell. Probing the mechanical regulation, we discovered that stiffer pillars or partial actomyosin contractility inhibition enhances inter-adhesion F-actin synchronization, and that inhibition of Arp2/3, but not formin, reduces synchronization. Our results suggest that adhesions can communicate and highlight the potential of using micropillar arrays as a tool to measure spatiotemporal intracellular signaling.
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Affiliation(s)
- Sarit Hollander
- Department of Software and Information Systems Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yuanning Guo
- Department of Genetics and Developmental Biology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Haguy Wolfenson
- Department of Genetics and Developmental Biology, Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa 31096, Israel
| | - Assaf Zaritsky
- Department of Software and Information Systems Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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11
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Ono S. Overexpression of Lifeact in the C. elegans body wall muscle causes sarcomere disorganization and embryonic or larval lethality. Front Cell Dev Biol 2024; 12:1504980. [PMID: 39605982 PMCID: PMC11599240 DOI: 10.3389/fcell.2024.1504980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2024] [Accepted: 10/25/2024] [Indexed: 11/29/2024] Open
Abstract
Lifeact is a short peptide that is widely utilized as a probe for actin filaments in live imaging. However, high concentrations of Lifeact can alter actin filament dynamics and cause artificial modifications to the actin cytoskeleton. Here, I evaluated Caenorhabditis elegans strains expressing Lifeact fused to fluorescent proteins in the body wall muscle. I found that, while low-level expression of Lifeact from a single-copy transgene was appropriate for labeling sarcomeric actin filaments, overexpression of Lifeact from an extrachromosomal array causes severe disorganization of muscle sarcomeres and lethality at an embryonic or larval stage. Therefore, for imaging studies in C. elegans, Lifeact needs to be kept at a low level by proper management of the expression system.
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Affiliation(s)
- Shoichiro Ono
- Departments of Pathology and Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, United States
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12
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Shubhrasmita Sahu S, Sarkar P, Chattopadhyay A. Quantitation of F-actin in cytoskeletal reorganization: Context, methodology and implications. Methods 2024; 230:44-58. [PMID: 39074540 DOI: 10.1016/j.ymeth.2024.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 07/08/2024] [Accepted: 07/17/2024] [Indexed: 07/31/2024] Open
Abstract
The actin cytoskeleton is involved in a large number of cellular signaling events in addition to providing structural integrity to the cell. Actin polymerization is a key event during cellular signaling. Although the role of actin cytoskeleton in cellular processes such as trafficking and motility has been extensively studied, the reorganization of the actin cytoskeleton upon signaling has been rarely explored due to lack of suitable assays. Keeping in mind this lacuna, we developed a confocal microscopy based approach that relies on high magnification imaging of cellular F-actin, followed by image reconstruction using commercially available software. In this review, we discuss the context and relevance of actin quantitation, followed by a detailed hands-on approach of the methodology involved with specific points on troubleshooting and useful precautions. In the latter part of the review, we elucidate the method by discussing applications of actin quantitation from our work in several important problems in contemporary membrane biology ranging from pathogen entry into host cells, to GPCR signaling and membrane-cytoskeleton interaction. We envision that future discovery of cell-permeable novel fluorescent probes, in combination with genetically encoded actin-binding reporters, would allow real-time visualization of actin cytoskeleton dynamics to gain deeper insights into active cellular processes in health and disease.
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Affiliation(s)
- Subhashree Shubhrasmita Sahu
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Parijat Sarkar
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India; Department of Biochemistry, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Amitabha Chattopadhyay
- CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India.
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13
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Davutoglu MG, Geyer VF, Niese L, Soltwedel JR, Zoccoler ML, Sabatino V, Haase R, Kröger N, Diez S, Poulsen N. Gliding motility of the diatom Craspedostauros australis coincides with the intracellular movement of raphid-specific myosins. Commun Biol 2024; 7:1187. [PMID: 39313522 PMCID: PMC11420354 DOI: 10.1038/s42003-024-06889-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Accepted: 09/12/2024] [Indexed: 09/25/2024] Open
Abstract
Raphid diatoms are one of the few eukaryotes capable of gliding motility, which is remarkably fast and allows for quasi-instantaneous directional reversals. Besides other mechanistic models, it has been suggested that an actomyosin system provides the force for diatom gliding. However, in vivo data on the dynamics of actin and myosin in diatoms are lacking. In this study, we demonstrate that the raphe-associated actin bundles required for diatom movement do not exhibit a directional turnover of subunits and thus their dynamics do not contribute directly to force generation. By phylogenomic analysis, we identified four raphid diatom-specific myosins in Craspedostauros australis (CaMyo51A-D) and investigated their in vivo localization and dynamics through GFP-tagging. Only CaMyo51B-D but not CaMyo51A exhibited coordinated movement during gliding, consistent with a role in force generation. The characterization of raphid diatom-specific myosins lays the foundation for unraveling the molecular mechanisms that underlie the gliding motility of diatoms.
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Affiliation(s)
- Metin G Davutoglu
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany
| | - Veikko F Geyer
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany
| | - Lukas Niese
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany
| | - Johannes R Soltwedel
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, Dresden, Germany
| | - Marcelo L Zoccoler
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, Dresden, Germany
| | - Valeria Sabatino
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany
| | - Robert Haase
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, Dresden, Germany
- Center for Scalable Data Analytics and Artificial Intelligence, Faculty of Mathematics and Computer Science, Leipzig University, Leipzig, Germany
| | - Nils Kröger
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, Dresden, Germany
- Faculty of Chemistry and Food Chemistry, TUD Dresden University of Technology, Dresden, Germany
| | - Stefan Diez
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany.
- Cluster of Excellence Physics of Life, TUD Dresden University of Technology, Dresden, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Nicole Poulsen
- B CUBE - Center for Molecular Bioengineering, TUD Dresden University of Technology, Dresden, Germany.
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14
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Gunasekara H, Perera T, Chao CJ, Bruno J, Saed B, Anderson J, Zhao Z, Hu YS. Phalloidin-PAINT: Enhanced quantitative nanoscale imaging of F-actin. Biophys J 2024; 123:3051-3064. [PMID: 38961624 PMCID: PMC11427775 DOI: 10.1016/j.bpj.2024.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/29/2024] [Accepted: 07/01/2024] [Indexed: 07/05/2024] Open
Abstract
We present phalloidin-based points accumulation for imaging in nanoscale topography (phalloidin-PAINT), enabling quantitative superresolution imaging of filamentous actin (F-actin) in the cell body and delicate membrane protrusions. We demonstrate that the intrinsic phalloidin dissociation enables PAINT superresolution microscopy in an imaging buffer containing low concentrations of dye-conjugated phalloidin. We further show enhanced single-molecule labeling by chemically promoting phalloidin dissociation. Two benefits of phalloidin-PAINT are its ability to consistently quantify F-actin at the nanoscale throughout the entire cell and its enhanced preservation of fragile cellular structures. In a proof-of-concept study, we employed phalloidin-PAINT to superresolve F-actin structures in U2OS and dendritic cells (DCs). We demonstrate more consistent F-actin quantification in the cell body and structurally delicate membrane protrusions of DCs compared with direct stochastic optical reconstruction microscopy (dSTORM). Using DC2.4 mouse DCs as the model system, we show F-actin redistribution from podosomes to actin filaments and altered prevalence of F-actin-associated membrane protrusions on the culture glass surface after lipopolysaccharide exposure. The concept of our work opens new possibilities for quantitative protein-specific PAINT using commercially available reagents.
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Affiliation(s)
- Hirushi Gunasekara
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, Illinois
| | - Thilini Perera
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, Illinois
| | - Chih-Jia Chao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, Illinois
| | - Joshua Bruno
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, Illinois
| | - Badeia Saed
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, Illinois
| | - Jesse Anderson
- Department of Chemical Engineering, College of Engineering, University of Illinois Chicago, Chicago, Illinois
| | - Zongmin Zhao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, Illinois
| | - Ying S Hu
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, Illinois.
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15
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Notario Manzano R, Chaze T, Rubinstein E, Penard E, Matondo M, Zurzolo C, Brou C. Proteomic landscape of tunneling nanotubes reveals CD9 and CD81 tetraspanins as key regulators. eLife 2024; 13:RP99172. [PMID: 39250349 PMCID: PMC11383530 DOI: 10.7554/elife.99172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/11/2024] Open
Abstract
Tunneling nanotubes (TNTs) are open actin- and membrane-based channels, connecting remote cells and allowing direct transfer of cellular material (e.g. vesicles, mRNAs, protein aggregates) from the cytoplasm to the cytoplasm. Although they are important especially, in pathological conditions (e.g. cancers, neurodegenerative diseases), their precise composition and their regulation were still poorly described. Here, using a biochemical approach allowing to separate TNTs from cell bodies and from extracellular vesicles and particles (EVPs), we obtained the full composition of TNTs compared to EVPs. We then focused on two major components of our proteomic data, the CD9 and CD81 tetraspanins, and further investigated their specific roles in TNT formation and function. We show that these two tetraspanins have distinct non-redundant functions: CD9 participates in stabilizing TNTs, whereas CD81 expression is required to allow the functional transfer of vesicles in the newly formed TNTs, possibly by regulating docking to or fusion with the opposing cell.
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Affiliation(s)
- Roberto Notario Manzano
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS 18 UMR 3691, Institut Pasteur, Université Paris Cité, Paris, France
- Sorbonne Université, ED394 - Physiologie, Physiopathologie et Thérapeutique, Paris, France
| | - Thibault Chaze
- Proteomics Platform, Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, Paris, France
| | - Eric Rubinstein
- Centre d'Immunologie et des Maladies Infectieuses, Inserm, CNRS, Sorbonne Université, CIMI-Paris, Paris, France
| | - Esthel Penard
- Ultrastructural BioImaging Core Facility (UBI), C2RT, Institut Pasteur, Université Paris Cité, Paris, France
| | - Mariette Matondo
- Proteomics Platform, Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, Paris, France
| | - Chiara Zurzolo
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS 18 UMR 3691, Institut Pasteur, Université Paris Cité, Paris, France
| | - Christel Brou
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS 18 UMR 3691, Institut Pasteur, Université Paris Cité, Paris, France
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16
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Green NM, Talbot D, Tootle TL. Nuclear actin is a critical regulator of Drosophila female germline stem cell maintenance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.27.609996. [PMID: 39253513 PMCID: PMC11383290 DOI: 10.1101/2024.08.27.609996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/11/2024]
Abstract
Nuclear actin has been implicated in regulating cell fate, differentiation, and cellular reprogramming. However, its roles in development and tissue homeostasis remain largely unknown. Here we uncover the role of nuclear actin in regulating stemness using Drosophila ovarian germline stem cells (GSCs) as a model. We find that the localization and structure of nuclear actin is dynamic in the early germ cells. Nuclear actin recognized by anti-actin C4 is found in both the nucleoplasm and nucleolus of GSCs. The polymeric nucleoplasmic C4 pool is lost after the 2-cell stage, whereas the monomeric nucleolar pool persists to the 8-cell stage, suggesting that polymeric nuclear actin may contribute to stemness. To test this idea, we overexpressed nuclear targeted actin constructs to alter nuclear actin polymerization states in the GSCs and early germ cells. Increasing monomeric nuclear actin, but not polymerizable nuclear actin, causes GSC loss that ultimately results in germline loss. This GSC loss is rescued by simultaneous overexpression of monomeric and polymerizable nuclear actin. Together these data reveal that GSC maintenance requires polymeric nuclear actin. This polymeric nuclear actin likely plays numerous roles in the GSCs, as increasing monomeric nuclear actin disrupts nuclear architecture causing nucleolar hypertrophy, distortion of the nuclear lamina, and heterochromatin reorganization; all factors critical for GSC maintenance and function. These data provide the first evidence that nuclear actin, and in particular, its ability to polymerize, are critical for stem cell function and tissue homeostasis in vivo.
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Affiliation(s)
- Nicole M. Green
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, 51 Newton Rd, 1-500 BSB, Iowa City, IA 52242
- Current affiliation: Biology, Cornell College, 600 First Street SW, Mount Vernon, IA 52314
| | - Danielle Talbot
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, 51 Newton Rd, 1-500 BSB, Iowa City, IA 52242
- Current affiliation: Biology, University of Iowa, 129 E. Jefferson St, 246 BB, Iowa City, IA 52242
| | - Tina L. Tootle
- Anatomy and Cell Biology, University of Iowa Carver College of Medicine, 51 Newton Rd, 1-500 BSB, Iowa City, IA 52242
- Current affiliation: Biology, University of Iowa, 129 E. Jefferson St, 246 BB, Iowa City, IA 52242
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17
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Wong VC, Houlihan PR, Liu H, Walpita D, DeSantis MC, Liu Z, O'Shea EK. Plasticity-induced actin polymerization in the dendritic shaft regulates intracellular AMPA receptor trafficking. eLife 2024; 13:e80622. [PMID: 39146380 PMCID: PMC11326776 DOI: 10.7554/elife.80622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/09/2024] [Indexed: 08/17/2024] Open
Abstract
AMPA-type receptors (AMPARs) are rapidly inserted into synapses undergoing plasticity to increase synaptic transmission, but it is not fully understood if and how AMPAR-containing vesicles are selectively trafficked to these synapses. Here, we developed a strategy to label AMPAR GluA1 subunits expressed from their endogenous loci in cultured rat hippocampal neurons and characterized the motion of GluA1-containing vesicles using single-particle tracking and mathematical modeling. We find that GluA1-containing vesicles are confined and concentrated near sites of stimulation-induced structural plasticity. We show that confinement is mediated by actin polymerization, which hinders the active transport of GluA1-containing vesicles along the length of the dendritic shaft by modulating the rheological properties of the cytoplasm. Actin polymerization also facilitates myosin-mediated transport of GluA1-containing vesicles to exocytic sites. We conclude that neurons utilize F-actin to increase vesicular GluA1 reservoirs and promote exocytosis proximal to the sites of synaptic activity.
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Affiliation(s)
- Victor C Wong
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Patrick R Houlihan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Hui Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Deepika Walpita
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Michael C DeSantis
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Zhe Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Erin K O'Shea
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
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18
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Salluce G, Folgar-Cameán Y, Barba-Bon A, Nikšić-Franjić I, El Anwar S, Grüner B, Lostalé-Seijo I, Nau WM, Montenegro J. Size and Polarizability of Boron Cluster Carriers Modulate Chaotropic Membrane Transport. Angew Chem Int Ed Engl 2024; 63:e202404286. [PMID: 38712936 DOI: 10.1002/anie.202404286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 04/24/2024] [Accepted: 05/02/2024] [Indexed: 05/08/2024]
Abstract
Perhalogenated closo-borates represent a new class of membrane carriers. They owe this activity to their chaotropicity, which enables the transport of hydrophilic molecules across model membranes and into living cells. The transport efficiency of this new class of cluster carriers depends on a careful balance between their affinity to membranes and cargo, which varies with chaotropicity. However, the structure-activity parameters that define chaotropic transport remain to be elucidated. Here, we have studied the modulation of chaotropic transport by decoupling the halogen composition from the boron core size. The binding affinity between perhalogenated decaborate and dodecaborate clusters carriers was quantified with different hydrophilic model cargos, namely a neutral and a cationic peptide, phalloidin and (KLAKLAK)2. The transport efficiency, membrane-lytic properties, and cellular toxicity, as obtained from different vesicle and cell assays, increased with the size and polarizability of the clusters. These results validate the chaotropic effect as the driving force behind the membrane transport propensity of boron clusters. This work advances our understanding of the structural features of boron cluster carriers and establishes the first set of rational design principles for chaotropic membrane transporters.
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Affiliation(s)
- Giulia Salluce
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15705, Santiago de Compostela, Spain
| | - Yeray Folgar-Cameán
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15705, Santiago de Compostela, Spain
| | - Andrea Barba-Bon
- School of Science, Constructor University, Campus Ring 1, 28759, Bremen, Germany
| | - Ivana Nikšić-Franjić
- School of Science, Constructor University, Campus Ring 1, 28759, Bremen, Germany
| | - Suzan El Anwar
- Institute of Inorganic Chemistry, Czech Academy of Sciences, v.v.i. Hlavní 1001, CZ-250 68, Řež, Czech Republic
| | - Bohumír Grüner
- Institute of Inorganic Chemistry, Czech Academy of Sciences, v.v.i. Hlavní 1001, CZ-250 68, Řež, Czech Republic
| | - Irene Lostalé-Seijo
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15705, Santiago de Compostela, Spain
| | - Werner M Nau
- School of Science, Constructor University, Campus Ring 1, 28759, Bremen, Germany
| | - Javier Montenegro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15705, Santiago de Compostela, Spain
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19
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Effiong UM, Khairandish H, Ramirez-Velez I, Wang Y, Belardi B. Turn-on protein switches for controlling actin binding in cells. Nat Commun 2024; 15:5840. [PMID: 38992021 PMCID: PMC11239668 DOI: 10.1038/s41467-024-49934-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 06/26/2024] [Indexed: 07/13/2024] Open
Abstract
Within a shared cytoplasm, filamentous actin (F-actin) plays numerous and critical roles across the cell body. Cells rely on actin-binding proteins (ABPs) to organize F-actin and to integrate its polymeric characteristics into diverse cellular processes. Yet, the multitude of ABPs that engage with and shape F-actin make studying a single ABP's influence on cellular activities a significant challenge. Moreover, without a means of manipulating actin-binding subcellularly, harnessing the F-actin cytoskeleton for synthetic biology purposes remains elusive. Here, we describe a suite of designed proteins, Controllable Actin-binding Switch Tools (CASTs), whose actin-binding behavior can be controlled with external stimuli. CASTs were developed that respond to different external inputs, providing options for turn-on kinetics and enabling orthogonality and multiplexing. Being genetically encoded, we show that CASTs can be inserted into native protein sequences to control F-actin association locally and engineered into structures to control cell and tissue shape and behavior.
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Affiliation(s)
- Unyime M Effiong
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Hannah Khairandish
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Isabela Ramirez-Velez
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Yanran Wang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Brian Belardi
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
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20
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Medina-Ruíz GI, Medina-Ruiz AI, Morán J. Fraping: A computational tool for detecting slight differences in fluorescence recovery after photobleaching (FRAP) data for actin polymerization analysis. Microsc Res Tech 2024; 87:1541-1551. [PMID: 38425281 DOI: 10.1002/jemt.24533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/02/2024]
Abstract
Fluorescence recovery after photobleaching (FRAP) is a laser method of light microscopy to evaluate the rapid movement of fluorescent molecules. To have a more reliable approach to analyze data from FRAP, we designed Fraping, a free access R library to data analysis obtained from FRAP. Unlike other programs, Fraping has a new form of analyzing curves of FRAP using statistical analysis based on the average curve difference. To evaluate our library, we analyzed the differences of actin polymerization in real time between dendrites and secondary neurites of cultured neuron transfected with LifeAct to track F-actin changes of neurites. We found that Fraping provided greater sensitivity than the conventional model using mobile fraction analysis. Likewise, this approach allowed us to normalize the fluorescence to the size area of interest and adjust data curves choosing the best parametric model. In addition, this library was supplemented with data simulation to have a more significant enrichment for the analysis behavior. We concluded that Fraping is a method that reduces bias when analyzing two data groups as compared with the conventional methods. This method also allows the users to choose a more suitable analysis approach according to their requirements. RESEARCH HIGHLIGHTS: Fraping is a new programming tool to analyze FRAP data to normalize fluorescence recovery curves. The conventional method uses one-point analysis, and the new one compares all the points to define the similarity of the fluorescence recovery.
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Affiliation(s)
- Gabriela Itzetl Medina-Ruíz
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Posgrado en Ciencias Biológicas, Unidad de Posgrado, Ciudad Universitaria, Mexico City, Mexico
| | | | - Julio Morán
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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21
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Ehrlich H, Voronkina A, Tabachniсk K, Kubiak A, Ereskovsky A, Jesionowski T. Silactins and Structural Diversity of Biosilica in Sponges. Biomimetics (Basel) 2024; 9:393. [PMID: 39056834 PMCID: PMC11274843 DOI: 10.3390/biomimetics9070393] [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: 05/29/2024] [Revised: 06/23/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
Sponges (phylum Porifera) were among the first metazoans on Earth, and represent a unique global source of highly structured and diverse biosilica that has been formed and tested over more than 800 million years of evolution. Poriferans are recognized as a unique archive of siliceous multiscaled skeletal constructs with superficial micro-ornamentation patterned by biopolymers. In the present study, spicules and skeletal frameworks of selected representatives of sponges in such classes as Demospongiae, Homoscleromorpha, and Hexactinellida were desilicified using 10% HF with the aim of isolating axial filaments, which resemble the shape and size of the original structures. These filaments were unambiguously identified in all specimens under study as F-actin, using the highly specific indicators iFluor™ 594-Phalloidin, iFluor™ 488-Phalloidin, and iFluor™ 350-Phalloidin. The identification of this kind of F-actins, termed for the first time as silactins, as specific pattern drivers in skeletal constructs of sponges opens the way to the fundamental understanding of their skeletogenesis. Examples illustrating the biomimetic potential of sophisticated poriferan biosilica patterned by silactins are presented and discussed.
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Affiliation(s)
- Hermann Ehrlich
- Center of Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61-614 Poznan, Poland;
- Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Alona Voronkina
- Pharmacy Department, National Pirogov Memorial Medical University, Vinnytsya, Pirogov Street 56, 21018 Vinnytsia, Ukraine;
| | - Konstantin Tabachniсk
- International Institute of Biomineralogy GmbH, Am St.-Niclas Schacht 13, 09599 Freiberg, Germany
| | - Anita Kubiak
- Center of Advanced Technology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 10, 61-614 Poznan, Poland;
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland
| | - Alexander Ereskovsky
- IMBE, CNRS, IRD, Aix Marseille University, Station Marine d’Endoume, Rue de la Batterie des Lions, 13007 Marseille, France;
| | - Teofil Jesionowski
- Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
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22
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He X, Brakebusch C. Regulation of Precise DNA Repair by Nuclear Actin Polymerization: A Chance for Improving Gene Therapy? Cells 2024; 13:1093. [PMID: 38994946 PMCID: PMC11240418 DOI: 10.3390/cells13131093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/13/2024] Open
Abstract
Although more difficult to detect than in the cytoplasm, it is now clear that actin polymerization occurs in the nucleus and that it plays a role in the specific processes of the nucleus such as transcription, replication, and DNA repair. A number of studies suggest that nuclear actin polymerization is promoting precise DNA repair by homologous recombination, which could potentially be of help for precise genome editing and gene therapy. This review summarizes the findings and describes the challenges and chances in the field.
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Affiliation(s)
| | - Cord Brakebusch
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark;
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23
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Ioannou IA, Brooks NJ, Kuimova MK, Elani Y. Visualizing Actin Packing and the Effects of Actin Attachment on Lipid Membrane Viscosity Using Molecular Rotors. JACS AU 2024; 4:2041-2049. [PMID: 38818078 PMCID: PMC11134356 DOI: 10.1021/jacsau.4c00237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/10/2024] [Accepted: 04/11/2024] [Indexed: 06/01/2024]
Abstract
The actin cytoskeleton and its elaborate interplay with the plasma membrane participate in and control numerous biological processes in eukaryotic cells. Malfunction of actin networks and changes in their dynamics are related to various diseases, from actin myopathies to uncontrolled cell growth and tumorigenesis. Importantly, the biophysical and mechanical properties of actin and its assemblies are deeply intertwined with the biological functions of the cytoskeleton. Novel tools to study actin and its associated biophysical features are, therefore, of prime importance. Here we develop a new approach which exploits fluorescence lifetime imaging microscopy (FLIM) and environmentally sensitive fluorophores termed molecular rotors, acting as quantitative microviscosity sensors, to monitor dynamic viscoelastic properties of both actin structures and lipid membranes. In order to reproduce a minimal actin cortex in synthetic cell models, we encapsulated and attached actin networks to the lipid bilayer of giant unilamellar vesicles (GUVs). Using a cyanine-based molecular rotor, DiSC2(3), we show that different types of actin bundles are characterized by distinct packing, which can be spatially resolved using FLIM. Similarly, we show that a lipid bilayer-localized molecular rotor can monitor the effects of attaching cross-linked actin networks to the lipid membrane, revealing an increase in membrane viscosity upon actin attachment. Our approach bypasses constraints associated with existing methods for actin imaging, many of which lack the capability for direct visualization of biophysical properties. It can therefore contribute to a deeper understanding of the role that actin plays in fundamental biological processes and help elucidate the underlying biophysics of actin-related diseases.
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Affiliation(s)
- Ion A. Ioannou
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
| | - Nickolas J. Brooks
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Marina K. Kuimova
- Department
of Chemistry, Imperial College London, Molecular
Sciences Research Hub, London W12 0BZ, U.K.
| | - Yuval Elani
- Department
of Chemical Engineering, Imperial College
London, South Kensington, London SW7 2AZ, U.K.
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24
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Ivanova J, Benk AS, Schaefer JV, Dreier B, Hermann LO, Plückthun A, Missirlis D, Spatz JP. Designed Ankyrin Repeat Proteins as Actin Labels of Distinct Cytoskeletal Structures in Living Cells. ACS NANO 2024; 18:8919-8933. [PMID: 38489155 PMCID: PMC10976963 DOI: 10.1021/acsnano.3c12265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/27/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024]
Abstract
The orchestrated assembly of actin and actin-binding proteins into cytoskeletal structures coordinates cell morphology changes during migration, cytokinesis, and adaptation to external stimuli. The accurate and unbiased visualization of the diverse actin assemblies within cells is an ongoing challenge. We describe here the identification and use of designed ankyrin repeat proteins (DARPins) as synthetic actin binders. Actin-binding DARPins were identified through ribosome display and validated biochemically. When introduced or expressed inside living cells, fluorescently labeled DARPins accumulated at actin filaments, validated through phalloidin colocalization on fixed cells. Nevertheless, different DARPins displayed different actin labeling patterns: some DARPins labeled efficiently dynamic structures, such as filopodia, lamellipodia, and blebs, while others accumulated primarily in stress fibers. This differential intracellular distribution correlated with DARPin-actin binding kinetics, as measured by fluorescence recovery after photobleaching experiments. Moreover, the rapid arrest of actin dynamics induced by pharmacological treatment led to the fast relocalization of DARPins. Our data support the hypothesis that the localization of actin probes depends on the inherent dynamic movement of the actin cytoskeleton. Compared to the widely used LifeAct probe, one DARPin exhibited enhanced signal-to-background ratio while retaining a similar ability to label stress fibers. In summary, we propose DARPins as promising actin-binding proteins for labeling or manipulation in living cells.
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Affiliation(s)
- Julia
R. Ivanova
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Heidelberg
University, Faculty of Biosciences, 69120 Heidelberg, Germany
- Max
Planck School Matter to Life, Jahnstrasse 29, 69120 Heidelberg, Germany
| | - Amelie S. Benk
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Jonas V. Schaefer
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- CSL
Behring
AG, 3014 Bern, Switzerland
| | - Birgit Dreier
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Leon O. Hermann
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - Andreas Plückthun
- Department
of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Dimitris Missirlis
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Institute
for Molecular Systems Engineering and Advanced Materials, Heidelberg University, INF 225, D-69120 Heidelberg, Germany
| | - Joachim P. Spatz
- Department
of Cellular Biophysics, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
- Institute
for Molecular Systems Engineering and Advanced Materials, Heidelberg University, INF 225, D-69120 Heidelberg, Germany
- Max
Planck School Matter to Life, Jahnstrasse 29, 69120 Heidelberg, Germany
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25
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Gunasekara H, Perera T, Chao CJ, Bruno J, Saed B, Anderson J, Zhao Z, Hu YS. Quantitative Superresolution Imaging of F-Actin in the Cell Body and Cytoskeletal Protrusions Using Phalloidin-Based Single-Molecule Labeling and Localization Microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583337. [PMID: 38496456 PMCID: PMC10942307 DOI: 10.1101/2024.03.04.583337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
We present single-molecule labeling and localization microscopy (SMLLM) using dye-conjugated phalloidin to achieve enhanced superresolution imaging of filamentous actin (F-actin). We demonstrate that the intrinsic phalloidin dissociation enables SMLLM in an imaging buffer containing low concentrations of dye-conjugated phalloidin. We further show enhanced single-molecule labeling by chemically promoting phalloidin dissociation. Two benefits of phalloidin-based SMLLM are better preservation of cellular structures sensitive to mechanical and shear forces during standard sample preparation and more consistent F-actin quantification at the nanoscale. In a proof-of-concept study, we employed SMLLM to super-resolve F-actin structures in U2OS and dendritic cells (DCs) and demonstrate more consistent F-actin quantification in the cell body and structurally delicate cytoskeletal proportions, which we termed membrane fibers, of DCs compared to direct stochastic optical reconstruction microscopy (dSTORM). Using DC2.4 mouse dendritic cells as the model system, we show F-actin redistribution from podosomes to actin filaments and altered prevalence of F-actin-associated membrane fibers on the culture glass surface after lipopolysaccharide exposure. While our work demonstrates SMLLM for F-actin, the concept opens new possibilities for protein-specific single-molecule labeling and localization in the same step using commercially available reagents.
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Affiliation(s)
- Hirushi Gunasekara
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Thilini Perera
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Chih-Jia Chao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL, 60612, USA
| | - Joshua Bruno
- Department of Biological Sciences, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Badeia Saed
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Jesse Anderson
- Department of Chemical Engineering, College of Engineering, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Zongmin Zhao
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois Chicago, Chicago, IL, 60612, USA
| | - Ying S. Hu
- Department of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, Chicago, IL, 60607, USA
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26
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Niemirowicz GT, Carlevaro G, Campetella O, Bouvier LA, Mucci J. A versatile 2A peptide-based strategy for ectopic expression and endogenous gene tagging in Trypanosoma cruzi. Heliyon 2024; 10:e24595. [PMID: 38304823 PMCID: PMC10830525 DOI: 10.1016/j.heliyon.2024.e24595] [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: 08/23/2023] [Revised: 01/03/2024] [Accepted: 01/10/2024] [Indexed: 02/03/2024] Open
Abstract
Nearly all expression vectors currently available for Trypanosoma cruzi were conceived to produce a single primary transcript containing the genes of interest along with those that confer antibiotic resistance. However, since each messenger RNA (mRNA) matures separately, drug selection will only guarantee the expression of those derived from the selectable marker. Therefore, commonly a considerable fraction of the cells recovered after selection with these expression vectors, although resistant do not express the protein of interest. Consequently, in order to counteract this disadvantage, we developed vectors with an alternative arrangement in which the gene of interest and antibiotic resistance are fused sharing the same mRNA. To test this configuration, we included the coding sequence for the green fluorescent protein (mEGFP) linked to the one conferring neomycin resistance (Neo). Additionally, to allow for the production of two independent proteins the sequence for a Thosea asigna virus self-cleaving 2A peptide (T2A) was inserted in-between. Cells obtained with these vectors displayed higher mEGFP expression levels with more homogeneous transgenic parasite populations than those transfected with more conventional independent mRNA-based alternatives. Moreover, as determined by Western blot, 2A mediated fusion protein dissociation occurred with high efficiency in all parasite stages. In addition, these vectors could easily be transformed into endogenous tagging constructs that allowed the insertion, by ends-in homologous recombination, of a hemagglutinin tag (HA) fused to the actin gene. The use of 2A self-cleaving peptides in the context of single mRNA vectors represents an interesting strategy capable of improving ectopic transgene expression in T. cruzi as well as providing a simple alternative to more sophisticated methods, such as the one based on CRISPR/Cas9, for the endogenous labeling of genes.
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Affiliation(s)
| | | | - Oscar Campetella
- Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Universidad Nacional de San Martín–Escuela de Bio y Nanotecnologías (EByN). Campus Miguelete, 25 de Mayo y Francia (B1650HMP), San Martín, Argentina
| | - León A. Bouvier
- Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Universidad Nacional de San Martín–Escuela de Bio y Nanotecnologías (EByN). Campus Miguelete, 25 de Mayo y Francia (B1650HMP), San Martín, Argentina
| | - Juan Mucci
- Instituto de Investigaciones Biotecnológicas, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET). Universidad Nacional de San Martín–Escuela de Bio y Nanotecnologías (EByN). Campus Miguelete, 25 de Mayo y Francia (B1650HMP), San Martín, Argentina
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27
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Desroches S, Harris AR. Quantifying cytoskeletal organization from optical microscopy data. Front Cell Dev Biol 2024; 11:1327994. [PMID: 38234685 PMCID: PMC10792062 DOI: 10.3389/fcell.2023.1327994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/07/2023] [Indexed: 01/19/2024] Open
Abstract
The actin cytoskeleton plays a pivotal role in a broad range of physiological processes including directing cell shape and subcellular organization, determining cell mechanical properties, and sensing and transducing mechanical forces. The versatility of the actin cytoskeleton arises from the ability of actin filaments to assemble into higher order structures through their interaction with a vast set of regulatory proteins. Actin filaments assemble into bundles, meshes, and networks, where different combinations of these structures fulfill specific functional roles. Analyzing the organization and abundance of different actin structures from optical microscopy data provides a valuable metric for assessing cell physiological function and changes associated with disease. However, quantitative measurements of the size, abundance, orientation, and distribution of different types of actin structure remains challenging both from an experimental and image analysis perspective. In this review, we summarize image analysis methods for extracting quantitative values that can be used for characterizing the organization of actin structures and provide selected examples. We summarize the potential sample types and metric reported with different approaches as a guide for selecting an image analysis strategy.
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Affiliation(s)
- Sarah Desroches
- Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, ON, Canada
- Ottawa-Carleton Institute for Biomedical Engineering Graduate Program, Ottawa, ON, Canada
| | - Andrew R. Harris
- Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, ON, Canada
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28
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Effiong UM, Khairandish H, Ramirez-Velez I, Wang Y, Belardi B. Turn-On Protein Switches for Controlling Actin Binding in Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.26.561921. [PMID: 37961502 PMCID: PMC10634840 DOI: 10.1101/2023.10.26.561921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Within a shared cytoplasm, filamentous actin (F-actin) plays numerous and critical roles across the cell body. Cells rely on actin-binding proteins (ABPs) to organize F-actin and to integrate its polymeric characteristics into diverse cellular processes. Yet, the multitude of ABPs that engage with and shape F-actin make studying a single ABP's influence on cellular activities a significant challenge. Moreover, without a means of manipulating actin-binding subcellularly, harnessing the F-actin cytoskeleton for synthetic biology purposes remains elusive. Here, we describe a suite of designed proteins, Controllable Actin-binding Switch Tools (CASTs), whose actin-binding behavior can be controlled with external stimuli. CASTs were developed that respond to different external inputs, providing options for turn-on kinetics and enabling orthogonality. Being genetically encoded, we show that CASTs can be inserted into native protein sequences to control F-actin association locally and engineered into new structures to control cell and tissue shape and behavior.
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Affiliation(s)
- Unyime M. Effiong
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Hannah Khairandish
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Isabela Ramirez-Velez
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Yanran Wang
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Brian Belardi
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712
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29
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Bingham D, Jakobs CE, Wernert F, Boroni-Rueda F, Jullien N, Schentarra EM, Friedl K, Da Costa Moura J, van Bommel DM, Caillol G, Ogawa Y, Papandréou MJ, Leterrier C. Presynapses contain distinct actin nanostructures. J Cell Biol 2023; 222:e202208110. [PMID: 37578754 PMCID: PMC10424573 DOI: 10.1083/jcb.202208110] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 06/07/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
The architecture of the actin cytoskeleton that concentrates at presynapses remains poorly known, hindering our understanding of its roles in synaptic physiology. In this work, we measure and visualize presynaptic actin by diffraction-limited and super-resolution microscopy, thanks to a validated model of bead-induced presynapses in cultured neurons. We identify a major population of actin-enriched presynapses that concentrates more presynaptic components and shows higher synaptic vesicle cycling than their non-enriched counterparts. Pharmacological perturbations point to an optimal actin amount and the presence of distinct actin structures within presynapses. We directly visualize these nanostructures using Single Molecule Localization Microscopy (SMLM), defining three distinct types: an actin mesh at the active zone, actin rails between the active zone and deeper reserve pools, and actin corrals around the whole presynaptic compartment. Finally, CRISPR-tagging of endogenous actin allows us to validate our results in natural synapses between cultured neurons, confirming the role of actin enrichment and the presence of three types of presynaptic actin nanostructures.
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Affiliation(s)
- Dominic Bingham
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | | | - Florian Wernert
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Fanny Boroni-Rueda
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Nicolas Jullien
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | | | - Karoline Friedl
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
- Abbelight, Cachan, France
| | | | | | - Ghislaine Caillol
- CNRS, INP UMR7051, NeuroCyto, Aix Marseille Université, Marseille, France
| | - Yuki Ogawa
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
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30
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Hvorecny KL, Sladewski TE, De La Cruz EM, Kollman JM, Heaslip AT. Toxoplasma gondii actin filaments are tuned for rapid disassembly and turnover. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555340. [PMID: 37693530 PMCID: PMC10491163 DOI: 10.1101/2023.08.29.555340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
The cytoskeletal protein actin plays a critical role in the pathogenicity of Toxoplasma gondii, mediating invasion and egress, cargo transport, and organelle inheritance. Advances in live cell imaging have revealed extensive filamentous actin networks in the Apicomplexan parasite, but there is conflicting data regarding the biochemical and biophysical properties of Toxoplasma actin. Here, we imaged the in vitro assembly of individual Toxoplasma actin filaments in real time, showing that native, unstabilized filaments grow tens of microns in length. Unlike skeletal muscle actin, Toxoplasma filaments intrinsically undergo rapid treadmilling due to a high critical concentration, fast monomer dissociation, and rapid nucleotide exchange. Cryo-EM structures of stabilized and unstabilized filaments show an architecture like skeletal actin, with differences in assembly contacts in the D-loop that explain the dynamic nature of the filament, likely a conserved feature of Apicomplexan actin. This work demonstrates that evolutionary changes at assembly interfaces can tune dynamic properties of actin filaments without disrupting their conserved structure.
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Affiliation(s)
- Kelli L Hvorecny
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Thomas E Sladewski
- Department of Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Enrique M De La Cruz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520
| | - Justin M Kollman
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Aoife T Heaslip
- Department of Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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31
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Sun Y, Wang D, Shi M, Gong Y, Yin S, Jiao Y, Guo S. Genome-wide identification of actin-depolymerizing factor gene family and their expression patterns under various abiotic stresses in soybean ( Glycine max). FRONTIERS IN PLANT SCIENCE 2023; 14:1236175. [PMID: 37575943 PMCID: PMC10413265 DOI: 10.3389/fpls.2023.1236175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023]
Abstract
The actin-depolymerizing factor (ADF) encoded by a family of genes is highly conserved among eukaryotes and plays critical roles in the various processes of plant growth, development, and stress responses via the remodeling of the architecture of the actin cytoskeleton. However, the ADF family and the encoded proteins in soybean (Glycine max) have not yet been systematically investigated. In this study, 18 GmADF genes (GmADF1 - GmADF18) were identified in the soybean genome and were mapped to 14 different chromosomes. Phylogenetic analysis classified them into four groups, which was confirmed by their structure and the distribution of conserved motifs in the encoded proteins. Additionally, 29 paralogous gene pairs were identified in the GmADF family, and analysis of their Ka/Ks ratios indicated their purity-based selection during the evolutionary expansion of the soybean genome. The analysis of the expression profiles based on the RNA-seq and qRT-PCR data indicated that GmADFs were diversely expressed in different organs and tissues, with most of them responding actively to drought- and salt-induced stresses, suggesting the critical roles played by them in various biological processes. Overall, our study shows that GmADF genes may play a crucial role in response to various abiotic stresses in soybean, and the highly inducible candidate genes could be used for further functional studies and molecular breeding in soybean.
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Affiliation(s)
| | | | | | | | | | | | - Shangjing Guo
- School of Agricultural Science and Engineering, Liaocheng University, Liaocheng, China
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32
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Sadhu L, Tsopoulidis N, Hasanuzzaman M, Laketa V, Way M, Fackler OT. ARPC5 isoforms and their regulation by calcium-calmodulin-N-WASP drive distinct Arp2/3-dependent actin remodeling events in CD4 T cells. eLife 2023; 12:e82450. [PMID: 37162507 PMCID: PMC10171864 DOI: 10.7554/elife.82450] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 04/06/2023] [Indexed: 05/11/2023] Open
Abstract
CD4 T cell activation induces nuclear and cytoplasmic actin polymerization via the Arp2/3 complex to activate cytokine expression and strengthen T cell receptor (TCR) signaling. Actin polymerization dynamics and filament morphology differ between nucleus and cytoplasm. However, it is unclear how the Arp2/3 complex mediates distinct nuclear and cytoplasmic actin polymerization in response to a common stimulus. In humans, the ARP3, ARPC1, and ARPC5 subunits of the Arp2/3 complex exist as two different isoforms, resulting in complexes with different properties. Here, we show that the Arp2/3 subunit isoforms ARPC5 and ARPC5L play a central role in coordinating distinct actin polymerization events in CD4 T cells. While ARPC5L is heterogeneously expressed in individual CD4 T cells, it specifically drives nuclear actin polymerization upon T cell activation. In contrast, ARPC5 is evenly expressed in CD4 T cell populations and is required for cytoplasmic actin dynamics. Interestingly, nuclear actin polymerization triggered by a different stimulus, DNA replication stress, specifically requires ARPC5 but not ARPC5L. TCR signaling but not DNA replication stress induces nuclear actin polymerization via nuclear calcium-calmodulin signaling and N-WASP. Diversity in the molecular properties and individual expression patterns of ARPC5 subunit isoforms thus tailors Arp2/3-mediated actin polymerization to different physiological stimuli.
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Affiliation(s)
- Lopamudra Sadhu
- Department of Infectious Diseases, Integrative Virology, University Hospital HeidelbergHeidelbergGermany
| | - Nikolaos Tsopoulidis
- Department of Infectious Diseases, Integrative Virology, University Hospital HeidelbergHeidelbergGermany
| | - Md Hasanuzzaman
- Department of Infectious Diseases, Integrative Virology, University Hospital HeidelbergHeidelbergGermany
| | - Vibor Laketa
- Department of Infectious Diseases, Virology, University Hospital HeidelbergHeidelbergGermany
| | - Michael Way
- Cellular Signalling and Cytoskeletal Function Laboratory, The Francis Crick InstituteLondonUnited Kingdom
- Department of Infectious Disease, Imperial CollegeLondonUnited Kingdom
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital HeidelbergHeidelbergGermany
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Palumbieri MD, Merigliano C, Acosta DG, von Känel T, Welter B, Stoy H, Krietsch J, Ulferts S, Sanchi A, Grosse R, Chiolo I, Lopes M. Replication fork plasticity upon replication stress requires rapid nuclear actin polymerization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.534097. [PMID: 36993227 PMCID: PMC10055433 DOI: 10.1101/2023.03.24.534097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Cells rapidly respond to replication stress actively slowing fork progression and inducing fork reversal. How replication fork plasticity is achieved in the context of nuclear organization is currently unknown. Using nuclear actin probes in living and fixed cells, we visualized nuclear actin filaments in unperturbed S phase, rapidly extending in number and thickness upon genotoxic treatments, and taking frequent contact with replication factories. Chemically or genetically impairing nuclear actin polymerization shortly before these treatments prevents active fork slowing and abolishes fork reversal. Defective fork plasticity is linked to reduced recruitment of RAD51 and SMARCAL1 to nascent DNA. Conversely, PRIMPOL gains access to replicating chromatin, promoting unrestrained and discontinuous DNA synthesis, which is associated with increased chromosomal instability and decreased cellular resistance to replication stress. Hence, nuclear F-actin orchestrates replication fork plasticity and is a key molecular determinant in the rapid cellular response to genotoxic treatments.
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Schröder SK, Tag CG, Weiskirchen S, Weiskirchen R. Phalloidin Staining for F-Actin in Hepatic Stellate Cells. Methods Mol Biol 2023; 2669:55-66. [PMID: 37247054 DOI: 10.1007/978-1-0716-3207-9_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
During the development of liver fibrosis, hepatic stellate cells undergo a transition from a quiescent phenotype into a proliferative, fibrogenic, and contractile, α-smooth muscle actin-positive myofibroblast. These cells acquire properties that are strongly associated with the reorganization of the actin cytoskeleton. Actin possesses a unique ability to polymerize into filamentous actin (F-actin) form its monomeric globular state (G-actin). F-actin can form robust actin bundles and cytoskeletal networks by interacting with a number of actin-binding proteins that provide important mechanical and structural support for a multitude of cellular processes including intracellular transport, cell motility, polarity, cell shape, gene regulation, and signal transduction. Therefore, stains with actin-specific antibodies and phalloidin conjugates for actin staining are widely used to visualize actin structures in myofibroblasts. Here we present an optimized protocol for F-actin staining for hepatic stellate cells using a fluorescent phalloidin.
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Affiliation(s)
- Sarah K Schröder
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany.
| | - Carmen G Tag
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany
| | - Sabine Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany
| | - Ralf Weiskirchen
- Institut für Molekulare Pathobiochemie, Experimentelle Gentherapie und Klinische Chemie (IFMPEGKC), Universitätsklinikum Aachen AöR, Aachen, Germany.
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Minamide LS, Hylton R, Swulius M, Bamburg JR. Visualizing Cofilin-Actin Filaments by Immunofluorescence and CryoEM: Essential Steps for Observing Cofilactin in Cells. Methods Mol Biol 2022; 2593:265-281. [PMID: 36513938 DOI: 10.1007/978-1-0716-2811-9_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Fluorescence microscopy of cytoskeletal proteins in situ using immunolabeling, fluorescent reagents, or expression of tagged proteins has been a common practice for decades but often with too little regard for what might not be visualized. This is especially true for assembled filamentous actin (F-actin), for which binding of fluorescently labeled phalloidin is taken as the gold standard for its quantification even though it is well known that F-actin saturated with cofilin (cofilactin) binds neither fluorescently labeled phalloidin nor genetically encoded F-actin reporters, such as LifeAct. Here, using expressed fluorescent cofilactin reporters, we show that cofilactin is the major component of some actin-containing structures in both normal and stressed neurons and present various fixation, permeabilization, and cryo-preservation methods for optimizing its observation.
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Affiliation(s)
- Laurie S Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Ryan Hylton
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - Matthew Swulius
- Department of Biochemistry and Molecular Biology, Penn State College of Medicine, Hershey, PA, USA
| | - James R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA.
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36
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Rubin J, van Wijnen AJ, Uzer G. Architectural control of mesenchymal stem cell phenotype through nuclear actin. Nucleus 2022; 13:35-48. [PMID: 35133922 PMCID: PMC8837231 DOI: 10.1080/19491034.2022.2029297] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 11/18/2022] Open
Abstract
There is growing appreciation that architectural components of the nucleus regulate gene accessibility by altering chromatin organization. While nuclear membrane connector proteins link the mechanosensitive actin cytoskeleton to the nucleoskeleton, actin's contribution to the inner architecture of the nucleus remains enigmatic. Control of actin transport into the nucleus, plus the presence of proteins that control actin structure (the actin tool-box) within the nucleus, suggests that nuclear actin may support biomechanical regulation of gene expression. Cellular actin structure is mechanoresponsive: actin cables generated through forces experienced at the plasma membrane transmit force into the nucleus. We posit that dynamic actin remodeling in response to such biomechanical cues provides a novel level of structural control over the epigenetic landscape. We here propose to bring awareness to the fact that mechanical forces can promote actin transfer into the nucleus and control structural arrangements as illustrated in mesenchymal stem cells, thereby modulating lineage commitment.
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Affiliation(s)
- Janet Rubin
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Andre J. van Wijnen
- Department of Biochemistry, University of Vermont Medical School, Burlington, Vt, USA
| | - Gunes Uzer
- Department of Mechanical & Biomedical Engineering, Boise State University, Boise, ID, USA
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37
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Padhan SK, Bag J, Panda M, Biswal BK, Sahoo H, Mishra M, Sahu SN. Synthesis of First Coumarin Fluorescent Dye for Actin Visualization. Bioconjug Chem 2022; 33:2113-2120. [PMID: 36264777 DOI: 10.1021/acs.bioconjchem.2c00332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Selective fluorescence imaging of actin protein hugely depends on the fluorescently labeled actin-binding domain (ABD). Thus, it is always a challenging task to image the actin protein (in vivo or in vitro) directly with an ABD-free system. To overcome the limitations of actin imaging without an ABD, we have designed a facile and cost-effective red fluorescent coumarin dye 7-hydroxy-4-methyl-8-(4-(2-oxo-2H-chromen-3-yl)thiazol-2-ylimino)methyl-2H-chromen-2-one (CTC) for actin binding. The selective binding of the dye was investigated using the gut and eye of the model organism Drosophila melanogaster and C2C12 and SCC-9 cell lines. Our result suggests two major advantages of CTC over the dyes presently used for imaging actin proteins. First, the dye can bind to actin efficiently without any secondary intermediate. Second, it is much more stable at room temperature and exhibits excellent photostability. To the best of our knowledge, this is the first fluorescent dye that can bind to the actin protein without employing any secondary intermediate/actin-binding domain. These findings could pave the way for many biologists and physicists to successfully employ the CTC dye for imaging and tracking actin proteins by fluorescence microscopy in various in vivo and in vitro systems.
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Affiliation(s)
- Subrata Kumar Padhan
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Sambalpur 768019, Odisha, India
| | - Janmejaya Bag
- Neural Developmental Biology Lab, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Munmun Panda
- Cancer Drug Resistance Lab, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Bijesh Kumar Biswal
- Cancer Drug Resistance Lab, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Harekrushna Sahoo
- Biophysical and Protein Chemistry Lab, Department of Chemistry, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Monalisa Mishra
- Neural Developmental Biology Lab, Department of Life Science, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Satya Narayan Sahu
- School of Chemistry, Sambalpur University, Jyoti Vihar, Burla, Sambalpur 768019, Odisha, India
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Wang J, Fan Y, Mittal B, Sanger JM, Sanger JW. Comparison of incorporation of wild type and mutated actins into sarcomeres in skeletal muscle cells: A fluorescence recovery after photobleaching study. Cytoskeleton (Hoboken) 2022; 79:105-115. [PMID: 36085566 DOI: 10.1002/cm.21725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/11/2022] [Accepted: 08/31/2022] [Indexed: 01/30/2023]
Abstract
The α-actin mutation G15R in the nucleotide-binding pocket of skeletal muscle, causes severe actin myopathy in human skeletal muscles. Expressed in cultured embryonic quail skeletal myotubes, YFP-G15R-α-actin incorporates in sarcomeres in a pattern indistinguishable from wildtype YFP-α-actin. However, patches of YFP-G15R-α-actin form, resembling those in patients. Analyses with FRAP of incorporation of YFP-G15R-α-actin showed major differences between fast-exchanging plus ends of overlapping actin filaments in Z-bands, versus slow exchanging ends of overlapping thin filaments in the middle of sarcomeres. Wildtype skeletal muscle YFP-α-actin shows a faster rate of incorporation at plus ends of F-actin than at their minus ends. Incorporation of YFP-G15R-α-actin molecules is reduced at plus ends, increased at minus ends. The same relationship of wildtype YFP-α-actin incorporation is seen in myofibrils treated with cytochalasin-D: decreased dynamics at plus ends, increased dynamics at minus ends, and F-actin aggregates. Speculation: imbalance of normal polarized assembly of F-actin creates excess monomers that form F-actin aggregates. Two other severe skeletal muscle YFP-α-actin mutations (H40Y and V163L) not in the nucleotide pocket do not affect actin dynamics, and lack F-actin aggregates. These results indicate that normal α-actin plus and minus end dynamics are needed to maintain actin filament stability, and avoid F-actin patches.
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Affiliation(s)
- Jushuo Wang
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Yingli Fan
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Balraj Mittal
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jean M Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Joseph W Sanger
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, USA
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Pain C, Tolmie F, Wojcik S, Wang P, Kriechbaumer V. intER-ACTINg: the structure and dynamics of ER and actin are interlinked. J Microsc 2022. [PMID: 35985796 DOI: 10.1111/jmi.13139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/30/2022]
Abstract
The actin cytoskeleton is the driver of gross ER remodelling and the movement and positioning of other membrane-bound organelles such as Golgi bodies. Rapid ER membrane remodelling is a feature of most plant cells and is important for normal cellular processes, including targeted secretion, immunity and signalling. Modifications to the actin cytoskeleton, through pharmacological agents such as Latrunculin B and phalloidin, or disruption of normal myosin function also affect ER structure and/or dynamics. Here, we investigate the impact of changes in the actin cytoskeleton on structure and dynamics on the ER as well as in return the impact of modified ER structure on the architecture of the actin cytoskeleton. By expressing actin markers that affect actin dynamics, or expressing of ER-shaping proteins that influence ER architecture, we found that the structure of ER-actin networks is closely inter-related; affecting one component is likely to have a direct effect on the other. Therefore, our results indicate that a complicated regulatory machinery and cross-talk between these two structures must exist in plants to co-ordinate the function of ER-actin network during multiple subcellular processes. In addition, when considering organelle structure and dynamics, the choice of actin marker is essential in preventing off-target organelle structure and dynamics modifications. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Charlotte Pain
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Frances Tolmie
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Stefan Wojcik
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
| | - Pengwei Wang
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Verena Kriechbaumer
- Plant Cell Biology, Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK
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Extraction of accurate cytoskeletal actin velocity distributions from noisy measurements. Nat Commun 2022; 13:4749. [PMID: 35963858 PMCID: PMC9376101 DOI: 10.1038/s41467-022-31583-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Dynamic remodeling of the actin cytoskeleton is essential for many cellular processes. Tracking the movement of individual actin filaments can in principle shed light on how this complex behavior arises at the molecular level. However, the information that can be extracted from these measurements is often limited by low signal-to-noise ratios. We developed a Bayesian statistical approach to estimate true, underlying velocity distributions from the tracks of individual actin-associated fluorophores with quantified localization uncertainties. We found that the motion of filamentous (F)-actin in fibroblasts and endothelial cells was better described by a statistical jump process than by models in which filaments undergo continuous, diffusive movement. In particular, a model with exponentially distributed jump length- and time-scales recapitulated actin filament velocity distributions measured for the cell cortex, integrin-based adhesions, and stress fibers, suggesting that a common physical model can potentially describe actin filament dynamics in a variety of cellular contexts.
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41
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Erdener ŞE, Küreli G, Dalkara T. Contractile apparatus in CNS capillary pericytes. NEUROPHOTONICS 2022; 9:021904. [PMID: 35106320 PMCID: PMC8785978 DOI: 10.1117/1.nph.9.2.021904] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
Significance: Whether or not capillary pericytes contribute to blood flow regulation in the brain and retina has long been debated. This was partly caused by failure of detecting the contractile protein α -smooth muscle actin ( α -SMA) in capillary pericytes. Aim: The aim of this review is to summarize recent developments in detecting α -SMA and contractility in capillary pericytes and the relevant literature on the biology of actin filaments. Results: Evidence suggests that for visualization of the small amounts of α -SMA in downstream mid-capillary pericytes, actin depolymerization must be prevented during tissue processing. Actin filaments turnover is mainly based on de/re-polymerization rather than transcription of the monomeric form, hence, small amounts of α -SMA mRNA may evade detection by transcriptomic studies. Similarly, transgenic mice expressing fluorescent reporters under the α -SMA promoter may yield low fluorescence due to limited transcriptional activity in mid-capillary pericytes. Recent studies show that pericytes including mid-capillary ones express several actin isoforms and myosin heavy chain type 11, the partner of α -SMA in mediating contraction. Emerging evidence also suggests that actin polymerization in pericytes may have a role in regulating the tone of downstream capillaries. Conclusions: With guidance of actin biology, innovative labeling and imaging techniques can reveal the molecular machinery of contraction in pericytes.
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Affiliation(s)
- Şefik E. Erdener
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey
| | - Gülce Küreli
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey
| | - Turgay Dalkara
- Hacettepe University, Institute of Neurological Sciences and Psychiatry, Ankara, Turkey
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Abstract
The membrane translocation of hydrophilic substances constitutes a challenge for their application as therapeutic compounds and labelling probes1–4. To remedy this, charged amphiphilic molecules have been classically used as carriers3,5. However, such amphiphilic carriers may cause aggregation and non-specific membrane lysis6,7. Here we show that globular dodecaborate clusters, and prominently B12Br122−, can function as anionic inorganic membrane carriers for a broad range of hydrophilic cargo molecules (with molecular mass of 146–4,500 Da). We show that cationic and neutral peptides, amino acids, neurotransmitters, vitamins, antibiotics and drugs can be carried across liposomal membranes. Mechanistic transport studies reveal that the carrier activity is related to the superchaotropic nature of these cluster anions8–12. We demonstrate that B12Br122− affects cytosolic uptake of different small bioactive molecules, including the antineoplastic monomethyl auristatin F, the proteolysis targeting chimera dBET1 and the phalloidin toxin, which has been successfully delivered in living cells for cytoskeleton labelling. We anticipate the broad and distinct delivery spectrum of our superchaotropic carriers to be the starting point of conceptually distinct cell-biological, neurobiological, physiological and pharmaceutical studies. The superchaotropic nature of globular boron cluster anions enables direct passage of a wide range of molecules across lipid membranes.
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Abstract
Actin is a highly conserved protein in mammals. The actin dynamics is regulated by actin-binding proteins and actin-related proteins. Nuclear actin and these regulatory proteins participate in multiple nuclear processes, including chromosome architecture organization, chromatin remodeling, transcription machinery regulation, and DNA repair. It is well known that the dysfunctions of these processes contribute to the development of cancer. Moreover, emerging evidence has shown that the deregulated actin dynamics is also related to cancer. This chapter discusses how the deregulation of nuclear actin dynamics contributes to tumorigenesis via such various nuclear events.
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Affiliation(s)
- Yuanjian Huang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of General Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shengzhe Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jae-Il Park
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center and Health Science Center, Houston, TX, USA.
- Program in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Fiúza UM, Lemaire P. Methods for the Study of Apical Constriction During Ascidian Gastrulation. Methods Mol Biol 2022; 2438:377-413. [PMID: 35147954 DOI: 10.1007/978-1-0716-2035-9_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gastrulation is the first major morphogenetic event during ascidian embryogenesis. Ascidian gastrulation begins with the invagination of the endodermal progenitors, a two-step process driven by individual cell shape changes of endoderm cells. During the first step, endoderm cells constrict apically, thereby flattening the vegetal side of the embryo. During the second step, endoderm cells shorten along their apicobasal axis and tissue invagination ensues. Individual cell shape changes are mediated by localized actomyosin contractile activity. Here, we describe methods used during ascidian endoderm apical constriction to study myosin activity and cellular morphodynamics with confocal and light sheet microscopy and followed by quantitative image analysis.
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Affiliation(s)
- Ulla-Maj Fiúza
- Systems Bioengineering, DCEXS Universidad Pompeu Fabra, Barcelona, Spain.
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45
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Qu C, Roth R, Puapatanakul P, Loitman C, Hammad D, Genin GM, Miner JH, Suleiman HY. Three-Dimensional Visualization of the Podocyte Actin Network Using Integrated Membrane Extraction, Electron Microscopy, and Machine Learning. J Am Soc Nephrol 2022; 33:155-173. [PMID: 34758982 PMCID: PMC8763187 DOI: 10.1681/asn.2021020182] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 10/19/2021] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Actin stress fibers are abundant in cultured cells, but little is known about them in vivo. In podocytes, much evidence suggests that mechanobiologic mechanisms underlie podocyte shape and adhesion in health and in injury, with structural changes to actin stress fibers potentially responsible for pathologic changes to cell morphology. However, this hypothesis is difficult to rigorously test in vivo due to challenges with visualization. A technology to image the actin cytoskeleton at high resolution is needed to better understand the role of structures such as actin stress fibers in podocytes. METHODS We developed the first visualization technique capable of resolving the three-dimensional cytoskeletal network in mouse podocytes in detail, while definitively identifying the proteins that comprise this network. This technique integrates membrane extraction, focused ion-beam scanning electron microscopy, and machine learning image segmentation. RESULTS Using isolated mouse glomeruli from healthy animals, we observed actin cables and intermediate filaments linking the interdigitated podocyte foot processes to newly described contractile actin structures, located at the periphery of the podocyte cell body. Actin cables within foot processes formed a continuous, mesh-like, electron-dense sheet that incorporated the slit diaphragms. CONCLUSIONS Our new technique revealed, for the first time, the detailed three-dimensional organization of actin networks in healthy podocytes. In addition to being consistent with the gel compression hypothesis, which posits that foot processes connected by slit diaphragms act together to counterbalance the hydrodynamic forces across the glomerular filtration barrier, our data provide insight into how podocytes respond to mechanical cues from their surrounding environment.
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Affiliation(s)
- Chengqing Qu
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Robyn Roth
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Charles Loitman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Dina Hammad
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Guy M. Genin
- Department of Mechanical Engineering, National Science Foundation Science and Technology Center for Engineering Mechanobiology, Washington University in St. Louis, St. Louis, Missouri
| | - Jeffrey H. Miner
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri,Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
| | - Hani Y. Suleiman
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri
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Gaeta IM, Meenderink LM, Tyska MJ. A protocol for imaging microvilli biogenesis on the surface of cultured porcine kidney epithelial cell monolayers. STAR Protoc 2021; 2:100998. [PMID: 34950883 PMCID: PMC8672049 DOI: 10.1016/j.xpro.2021.100998] [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] [Indexed: 11/23/2022] Open
Abstract
A key facet of epithelial differentiation is the assembly of actin-based protrusions known as microvilli, which amplify apical membrane surface area for various cell functions. To probe mechanisms of microvillus assembly, we developed a protocol using spinning disk confocal microscopy to directly visualize microvillus biogenesis on the surface of cultured porcine kidney epithelial cell monolayers engineered to express fluorescent proteins. This protocol offers access to the molecular details of individual protrusion growth events at high spatiotemporal resolution. For complete details on the use and execution of this protocol, please refer to Gaeta et al. (2021).
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Affiliation(s)
- Isabella M. Gaeta
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Leslie M. Meenderink
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Veterans Affairs Tennessee Valley Health Care System, Nashville, TN 37212, USA
| | - Matthew J. Tyska
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
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47
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Koronfel M, Kounatidis I, Mwangangi DM, Vyas N, Okolo C, Jadhav A, Fish T, Chotchuang P, Schulte A, Robinson RC, Harkiolaki M. Correlative cryo-imaging of the cellular universe with soft X-rays and laser light used to track F-actin structures in mammalian cells. Acta Crystallogr D Struct Biol 2021; 77:1479-1485. [PMID: 34866605 PMCID: PMC8647181 DOI: 10.1107/s2059798321010329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/06/2021] [Indexed: 11/16/2022] Open
Abstract
Imaging of actin filaments is crucial due to the integral role that they play in many cellular functions such as intracellular transport, membrane remodelling and cell motility. Visualizing actin filaments has so far relied on fluorescence microscopy and electron microscopy/tomography. The former lacks the capacity to capture the overall local ultrastructure, while the latter requires rigorous sample preparation that can lead to potential artefacts, and only delivers relatively small volumes of imaging data at the thinnest areas of a cell. In this work, a correlative approach utilizing in situ super-resolution fluorescence imaging and cryo X-ray tomography was used to image bundles of actin filaments deep inside cells under near-native conditions. In this case, fluorescence 3D imaging localized the actin bundles within the intracellular space, while X-ray tomograms of the same areas provided detailed views of the local ultrastructure. Using this new approach, actin trails connecting vesicles in the perinuclear area and hotspots of actin presence within and around multivesicular bodies were observed. The characteristic prevalence of filamentous actin in cytoplasmic extensions was also documented.
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Affiliation(s)
- Mohamed Koronfel
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Ilias Kounatidis
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Dennis M. Mwangangi
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore
| | - Nina Vyas
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Chidinma Okolo
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Archana Jadhav
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Tom Fish
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Phatcharin Chotchuang
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| | - Albert Schulte
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| | - Robert C. Robinson
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
| | - Maria Harkiolaki
- Beamline B24, Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
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48
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Xu R, Du S. Overexpression of Lifeact-GFP Disrupts F-Actin Organization in Cardiomyocytes and Impairs Cardiac Function. Front Cell Dev Biol 2021; 9:746818. [PMID: 34765602 PMCID: PMC8576398 DOI: 10.3389/fcell.2021.746818] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/07/2021] [Indexed: 11/28/2022] Open
Abstract
Lifeact-GFP is a frequently used molecular probe to study F-actin structure and dynamic assembly in living cells. In this study, we generated transgenic zebrafish models expressing Lifeact-GFP specifically in cardiac muscles to investigate the effect of Lifeact-GFP on heart development and its application to study cardiomyopathy. The data showed that transgenic zebrafish with low to moderate levels of Lifeact-GFP expression could be used as a good model to study contractile dynamics of actin filaments in cardiac muscles in vivo. Using this model, we demonstrated that loss of Smyd1b, a lysine methyltransferase, disrupted F-actin filament organization in cardiomyocytes of zebrafish embryos. Our studies, however, also demonstrated that strong Lifeact-GFP expression in cardiomyocytes was detrimental to actin filament organization in cardiomyocytes that led to pericardial edema and early embryonic lethality of zebrafish embryos. Collectively, these data suggest that although Lifeact-GFP is a good probe for visualizing F-actin dynamics, transgenic models need to be carefully evaluated to avoid artifacts induced by Lifeact-GFP overexpression.
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Affiliation(s)
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
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49
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Garlick E, Thomas SG, Owen DM. Super-Resolution Imaging Approaches for Quantifying F-Actin in Immune Cells. Front Cell Dev Biol 2021; 9:676066. [PMID: 34490240 PMCID: PMC8416680 DOI: 10.3389/fcell.2021.676066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 05/20/2021] [Indexed: 11/21/2022] Open
Abstract
Immune cells comprise a diverse set of cells that undergo a complex array of biological processes that must be tightly regulated. A key component of cellular machinery that achieves this is the cytoskeleton. Therefore, imaging and quantitatively describing the architecture and dynamics of the cytoskeleton is an important research goal. Optical microscopy is well suited to this task. Here, we review the latest in the state-of-the-art methodology for labeling the cytoskeleton, fluorescence microscopy hardware suitable for such imaging and quantitative statistical analysis software applicable to describing cytoskeletal structures. We also highlight ongoing challenges and areas for future development.
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Affiliation(s)
- Evelyn Garlick
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Steven G Thomas
- Institute of Cardiovascular Sciences, College of Medical and Dental Science, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom
| | - Dylan M Owen
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, United Kingdom.,Institute for Immunology and Immunotherapy, College of Medical and Dental Science and School of Mathematics, College of Engineering and Physical Science, University of Birmingham, Birmingham, United Kingdom
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50
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Vlassakis J, Hansen LL, Higuchi-Sanabria R, Zhou Y, Tsui CK, Dillin A, Huang H, Herr AE. Measuring expression heterogeneity of single-cell cytoskeletal protein complexes. Nat Commun 2021; 12:4969. [PMID: 34404787 PMCID: PMC8371148 DOI: 10.1038/s41467-021-25212-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 07/23/2021] [Indexed: 02/07/2023] Open
Abstract
Multimeric cytoskeletal protein complexes orchestrate normal cellular function. However, protein-complex distributions in stressed, heterogeneous cell populations remain unknown. Cell staining and proximity-based methods have limited selectivity and/or sensitivity for endogenous multimeric protein-complex quantification from single cells. We introduce micro-arrayed, differential detergent fractionation to simultaneously detect protein complexes in hundreds of individual cells. Fractionation occurs by 60 s size-exclusion electrophoresis with protein complex-stabilizing buffer that minimizes depolymerization. Proteins are measured with a ~5-hour immunoassay. Co-detection of cytoskeletal protein complexes in U2OS cells treated with filamentous actin (F-actin) destabilizing Latrunculin A detects a unique subpopulation (~2%) exhibiting downregulated F-actin, but upregulated microtubules. Thus, some cells may upregulate other cytoskeletal complexes to counteract the stress of Latrunculin A treatment. We also sought to understand the effect of non-chemical stress on cellular heterogeneity of F-actin. We find heat shock may dysregulate filamentous and globular actin correlation. In this work, our assay overcomes selectivity limitations to biochemically quantify single-cell protein complexes perturbed with diverse stimuli.
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Affiliation(s)
- Julea Vlassakis
- Department of Bioengineering, University of California Berkeley, Berkeley, CA, USA
| | - Louise L Hansen
- Department of Bioengineering, University of California Berkeley, Berkeley, CA, USA
| | - Ryo Higuchi-Sanabria
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Yun Zhou
- Division of Biostatistics, University of California Berkeley, Berkeley, CA, USA
| | - C Kimberly Tsui
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Andrew Dillin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Haiyan Huang
- Department of Statistics, University of California Berkeley, Berkeley, CA, USA
- Center for Computational Biology, University of California Berkeley, Berkeley, CA, USA
| | - Amy E Herr
- Department of Bioengineering, University of California Berkeley, Berkeley, CA, USA.
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