1
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Hirschhäuser A, van Cann M, Bogdan S. CK1α protects WAVE from degradation to regulate cell shape and motility in immune response. J Cell Sci 2021; 134:272700. [PMID: 34730182 PMCID: PMC8714073 DOI: 10.1242/jcs.258891] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/25/2021] [Indexed: 12/02/2022] Open
Abstract
The WAVE regulatory complex (WRC) is the main activator of the Arp2/3 complex, promoting lamellipodial protrusions in migrating cells. The WRC is basally inactive but can be activated by Rac1 and phospholipids, and through phosphorylation. However, the in vivo relevance of the phosphorylation of WAVE proteins remains largely unknown. Here, we identified casein kinase I alpha (CK1α) as a regulator of WAVE, thereby controlling cell shape and cell motility in Drosophila macrophages. CK1α binds and phosphorylates WAVE in vitro. Phosphorylation of WAVE by CK1α appears not to be required for activation but, rather, regulates its stability. Pharmacologic inhibition of CK1α promotes ubiquitin-dependent degradation of WAVE. Consistently, loss of Ck1α but not ck2 function phenocopies the depletion of WAVE. Phosphorylation-deficient mutations in the CK1α consensus sequences within the VCA domain of WAVE can neither rescue mutant lethality nor lamellipodium defects. By contrast, phosphomimetic mutations rescue all cellular and developmental defects. Finally, RNAi-mediated suppression of 26S proteasome or E3 ligase complexes substantially rescues lamellipodia defects in CK1α-depleted macrophages. Therefore, we conclude that basal phosphorylation of WAVE by CK1α protects it from premature ubiquitin-dependent degradation, thus promoting WAVE function in vivo. This article has an associated First Person interview with the first author of the paper. Summary: We identified CK1α as a novel regulator of WAVE controlling cell shape and motility in immune response. Basal phosphorylation of WAVE by CK1α protects it from premature proteasomal degradation.
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Affiliation(s)
- Alexander Hirschhäuser
- Institute of Physiology and Pathophysiology, Dept. of Molecular Cell Physiology, Philipps-University Marburg, Germany
| | | | - Sven Bogdan
- Institute of Physiology and Pathophysiology, Dept. of Molecular Cell Physiology, Philipps-University Marburg, Germany.,Institute for Neurobiology, University of Münster, Germany
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2
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Reshetniak S, Rizzoli SO. Interrogating Synaptic Architecture: Approaches for Labeling Organelles and Cytoskeleton Components. Front Synaptic Neurosci 2019; 11:23. [PMID: 31507402 PMCID: PMC6716447 DOI: 10.3389/fnsyn.2019.00023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 08/02/2019] [Indexed: 01/06/2023] Open
Abstract
Synaptic transmission has been studied for decades, as a fundamental step in brain function. The structure of the synapse, and its changes during activity, turned out to be key aspects not only in the transfer of information between neurons, but also in cognitive processes such as learning and memory. The overall synaptic morphology has traditionally been studied by electron microscopy, which enables the visualization of synaptic structure in great detail. The changes in the organization of easily identified structures, such as the presynaptic active zone, or the postsynaptic density, are optimally studied via electron microscopy. However, few reliable methods are available for labeling individual organelles or protein complexes in electron microscopy. For such targets one typically relies either on combination of electron and fluorescence microscopy, or on super-resolution fluorescence microscopy. This review focuses on approaches and techniques used to specifically reveal synaptic organelles and protein complexes, such as cytoskeletal assemblies. We place the strongest emphasis on methods detecting the targets of interest by affinity binding, and we discuss the advantages and limitations of each method.
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Affiliation(s)
- Sofiia Reshetniak
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
- International Max Planck Research School for Molecular Biology, Göttingen, Germany
| | - Silvio O. Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration (BIN), University Medical Center Göttingen, Göttingen, Germany
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3
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Curry N, Ghézali G, Kaminski Schierle GS, Rouach N, Kaminski CF. Correlative STED and Atomic Force Microscopy on Live Astrocytes Reveals Plasticity of Cytoskeletal Structure and Membrane Physical Properties during Polarized Migration. Front Cell Neurosci 2017; 11:104. [PMID: 28469559 PMCID: PMC5396045 DOI: 10.3389/fncel.2017.00104] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 03/28/2017] [Indexed: 02/02/2023] Open
Abstract
The plasticity of the cytoskeleton architecture and membrane properties is important for the establishment of cell polarity, adhesion and migration. Here, we present a method which combines stimulated emission depletion (STED) super-resolution imaging and atomic force microscopy (AFM) to correlate cytoskeletal structural information with membrane physical properties in live astrocytes. Using STED compatible dyes for live cell imaging of the cytoskeleton, and simultaneously mapping the cell surface topology with AFM, we obtain unprecedented detail of highly organized networks of actin and microtubules in astrocytes. Combining mechanical data from AFM with optical imaging of actin and tubulin further reveals links between cytoskeleton organization and membrane properties. Using this methodology we illustrate that scratch-induced migration induces cytoskeleton remodeling. The latter is caused by a polarization of actin and microtubule elements within astroglial cell processes, which correlates strongly with changes in cell stiffness. The method opens new avenues for the dynamic probing of the membrane structural and functional plasticity of living brain cells. It is a powerful tool for providing new insights into mechanisms of cell structural remodeling during physiological or pathological processes, such as brain development or tumorigenesis.
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Affiliation(s)
- Nathan Curry
- Chemical Engineering and Biotechnology, University of CambridgeCambridge, UK
| | - Grégory Ghézali
- Chemical Engineering and Biotechnology, University of CambridgeCambridge, UK,Center for Interdisciplinary Research in Biology, College de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research UniversityParis, France,Doctoral School No 158, Pierre and Marie Curie UniversityParis, France
| | | | - Nathalie Rouach
- Chemical Engineering and Biotechnology, University of CambridgeCambridge, UK,Center for Interdisciplinary Research in Biology, College de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research UniversityParis, France,*Correspondence: Nathalie Rouach Clemens F. Kaminski
| | - Clemens F. Kaminski
- Chemical Engineering and Biotechnology, University of CambridgeCambridge, UK,*Correspondence: Nathalie Rouach Clemens F. Kaminski
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4
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Nagel BM, Bechtold M, Rodriguez LG, Bogdan S. Drosophila WASH is required for integrin-mediated cell adhesion, cell motility and lysosomal neutralization. J Cell Sci 2016; 130:344-359. [PMID: 27884932 DOI: 10.1242/jcs.193086] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
The Wiskott-Aldrich syndrome protein and SCAR homolog (WASH; also known as Washout in flies) is a conserved actin-nucleation-promoting factor controlling Arp2/3 complex activity in endosomal sorting and recycling. Previous studies have identified WASH as an essential regulator in Drosophila development. Here, we show that homozygous wash mutant flies are viable and fertile. We demonstrate that Drosophila WASH has conserved functions in integrin receptor recycling and lysosome neutralization. WASH generates actin patches on endosomes and lysosomes, thereby mediating both aforementioned functions. Consistently, loss of WASH function results in cell spreading and cell migration defects of macrophages, and an increased lysosomal acidification that affects efficient phagocytic and autophagic clearance. WASH physically interacts with the vacuolar (V)-ATPase subunit Vha55 that is crucial to establish and maintain lysosome acidification. As a consequence, starved flies that lack WASH function show a dramatic increase in acidic autolysosomes, causing a reduced lifespan. Thus, our data highlight a conserved role for WASH in the endocytic sorting and recycling of membrane proteins, such as integrins and the V-ATPase, that increase the likelihood of survival under nutrient deprivation.
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Affiliation(s)
- Benedikt M Nagel
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany.,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
| | - Meike Bechtold
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany
| | | | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestr. 9, 48149 Münster, Germany .,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
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5
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Eikenes ÅH, Malerød L, Lie-Jensen A, Sem Wegner C, Brech A, Liestøl K, Stenmark H, Haglund K. Src64 controls a novel actin network required for proper ring canal formation in the Drosophila male germline. Development 2016; 142:4107-18. [PMID: 26628094 DOI: 10.1242/dev.124370] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
In many organisms, germ cells develop as cysts in which cells are interconnected via ring canals (RCs) as a result of incomplete cytokinesis. However, the molecular mechanisms of incomplete cytokinesis remain poorly understood. Here, we address the role of tyrosine phosphorylation of RCs in the Drosophila male germline. We uncover a hierarchy of tyrosine phosphorylation within germline cysts that positively correlates with RC age. The kinase Src64 is responsible for mediating RC tyrosine phosphorylation, and loss of Src64 causes a reduction in RC diameter within germline cysts. Mechanistically, we show that Src64 controls an actin network around the RCs that depends on Abl and the Rac/SCAR/Arp2/3 pathway. The actin network around RCs is required for correct RC diameter in cysts of developing germ cells. We also identify that Src64 is required for proper germ cell differentiation in the Drosophila male germline independent of its role in RC regulation. In summary, we report that Src64 controls actin dynamics to mediate proper RC formation during incomplete cytokinesis during germline cyst development in vivo.
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Affiliation(s)
- Åsmund Husabø Eikenes
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Lene Malerød
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Anette Lie-Jensen
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Catherine Sem Wegner
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Andreas Brech
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Knut Liestøl
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway Department of Informatics, University of Oslo, Oslo N-0316, Norway
| | - Harald Stenmark
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
| | - Kaisa Haglund
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, Oslo N-0379, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, Oslo N-0379, Norway
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6
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Abstract
Super resolution imaging is becoming an increasingly important tool in the arsenal of methods available to cell biologists. In recognition of its potential, the Nobel Prize for chemistry was awarded to three investigators involved in the development of super resolution imaging methods in 2014. The availability of commercial instruments for super resolution imaging has further spurred the development of new methods and reagents designed to take advantage of super resolution techniques. Super resolution offers the advantages traditionally associated with light microscopy, including the use of gentle fixation and specimen preparation methods, the ability to visualize multiple elements within a single specimen, and the potential to visualize dynamic changes in living specimens over time. However, imaging of living cells over time is difficult and super resolution imaging is computationally demanding. In this review, we discuss the advantages/disadvantages of different super resolution systems for imaging fixed live specimens, with particular regard to cytoskeleton structures.
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Affiliation(s)
- Eric A Shelden
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Zachary T Colburn
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - Jonathan C R Jones
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
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7
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Zobel T, Brinkmann K, Koch N, Schneider K, Seemann E, Fleige A, Qualmann B, Kessels MM, Bogdan S. Cooperative functions of the two F-BAR proteins Cip4 and Nostrin in the regulation of E-cadherin in epithelial morphogenesis. J Cell Sci 2016; 128:499-515. [PMID: 25413347 DOI: 10.1242/jcs.155929] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
F-BAR proteins are prime candidates to regulate membrane curvature and dynamics during different developmental processes. Here, we analyzed nostrin, a so-far-unknown Drosophila melanogaster F-BAR protein related to Cip4. Genetic analyses revealed a strong synergism between nostrin and cip4 functions.Whereas single mutant flies are viable and fertile, combined loss of nostrin and cip4 results in reduced viability and fertility. Double mutant escaper flies show enhanced wing polarization defects and females exhibit strong egg chamber encapsulation defects. Live imaging analysis suggests that the observed phenotypes are caused by an impaired turnover of E-cadherin at the membrane. Simultaneous knockdown of Cip4 and Nostrin strongly increases the formation of tubular E-cadherin vesicles at adherens junctions. Cip4 and Nostrin localize at distinct membrane subdomains. Both proteins prefer similar membrane curvatures but seem to form distinct membrane coats and do not heterooligomerize. Our data suggest an important synergistic function of both F-BAR proteins in membrane dynamics. We propose a cooperative recruitment model, in which Cip4 initially promotes membrane invagination and early-actin-based endosomal motility, and Nostrin makes contacts with microtubules through the kinesin Khc-73 for trafficking of recycling endosomes.
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8
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Squarr AJ, Brinkmann K, Chen B, Steinbacher T, Ebnet K, Rosen MK, Bogdan S. Fat2 acts through the WAVE regulatory complex to drive collective cell migration during tissue rotation. J Cell Biol 2016; 212:591-603. [PMID: 26903538 PMCID: PMC4772498 DOI: 10.1083/jcb.201508081] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 01/19/2016] [Indexed: 12/02/2022] Open
Abstract
The atypical cadherin Fat2 binds the WAVE regulatory complex (WRC) and acts with receptor tyrosine phosphatase Dlar through the WRC to control collective cell migration during Drosophila oogenesis. Directional cell movements during morphogenesis require the coordinated interplay between membrane receptors and the actin cytoskeleton. The WAVE regulatory complex (WRC) is a conserved actin regulator. Here, we found that the atypical cadherin Fat2 recruits the WRC to basal membranes of tricellular contacts where a new type of planar-polarized whip-like actin protrusion is formed. Loss of either Fat2 function or its interaction with the WRC disrupts tricellular protrusions and results in the formation of nonpolarized filopodia. We provide further evidence for a molecular network in which the receptor tyrosine phosphatase Dlar interacts with the WRC to couple the extracellular matrix, the membrane, and the actin cytoskeleton during egg elongation. Our data uncover a mechanism by which polarity information can be transduced from a membrane receptor to a key actin regulator to control collective follicle cell migration during egg elongation. 4D-live imaging of rotating MCF10A mammary acini further suggests an evolutionary conserved mechanism driving rotational motions in epithelial morphogenesis.
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Affiliation(s)
- Anna Julia Squarr
- Institute for Neurobiology, University of Münster, 48149 Münster, Germany
| | - Klaus Brinkmann
- Institute for Neurobiology, University of Münster, 48149 Münster, Germany
| | - Baoyu Chen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Tim Steinbacher
- Institute-associated Research Group "Cell adhesion and cell polarity," University of Münster, 48149 Münster, Germany Institute of Medical Biochemistry, University of Münster, 48149 Münster, Germany Center for Molecular Biology of Inflammation, University of Münster, 48149 Münster, Germany
| | - Klaus Ebnet
- Institute-associated Research Group "Cell adhesion and cell polarity," University of Münster, 48149 Münster, Germany Institute of Medical Biochemistry, University of Münster, 48149 Münster, Germany Center for Molecular Biology of Inflammation, University of Münster, 48149 Münster, Germany
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390
| | - Sven Bogdan
- Institute for Neurobiology, University of Münster, 48149 Münster, Germany
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9
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Brüser L, Bogdan S. Molecular Control of Actin Dynamics In Vivo: Insights from Drosophila. Handb Exp Pharmacol 2016; 235:285-310. [PMID: 27757759 DOI: 10.1007/164_2016_33] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The actin cytoskeleton provides mechanical support for cells and generates forces to drive cell shape changes and cell migration in morphogenesis. Molecular understanding of actin dynamics requires a genetically traceable model system that allows interdisciplinary experimental approaches to elucidate the regulatory network of cytoskeletal proteins in vivo. Here, we will discuss some examples of how advances in Drosophila genetics and high-resolution imaging techniques contribute to the discovery of new actin functions, signaling pathways, and mechanisms of actin regulation in vivo.
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Affiliation(s)
- Lena Brüser
- Institute for Neurobiology, University of Muenster, Badestrasse 9, 48149, Muenster, Germany
| | - Sven Bogdan
- Institute for Neurobiology, University of Muenster, Badestrasse 9, 48149, Muenster, Germany.
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10
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Brinkmann K, Winterhoff M, Önel SF, Schultz J, Faix J, Bogdan S. WHAMY is a novel actin polymerase promoting myoblast fusion, macrophage cell motility and sensory organ development in Drosophila. J Cell Sci 2015; 129:604-20. [PMID: 26675239 DOI: 10.1242/jcs.179325] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 12/09/2015] [Indexed: 01/06/2023] Open
Abstract
Wiskott-Aldrich syndrome proteins (WASPs) are nucleation-promoting factors (NPF) that differentially control the Arp2/3 complex. In Drosophila, three different family members, SCAR (also known as WAVE), WASP and WASH (also known as CG13176), have been analyzed so far. Here, we characterized WHAMY, the fourth Drosophila WASP family member. whamy originated from a wasp gene duplication and underwent a sub-neofunctionalization. Unlike WASP, we found that WHAMY specifically interacted with activated Rac1 through its two CRIB domains, which were sufficient for targeting WHAMY to lamellipodial and filopodial tips. Biochemical analyses showed that WHAMY promoted exceptionally fast actin filament elongation, although it did not activate the Arp2/3 complex. Loss- and gain-of-function studies revealed an important function of WHAMY in membrane protrusions and cell migration in macrophages. Genetic data further implied synergistic functions between WHAMY and WASP during morphogenesis. Double mutants were late-embryonic lethal and showed severe defects in myoblast fusion. Trans-heterozygous mutant animals showed strongly increased defects in sensory cell fate specification. Thus, WHAMY is a novel actin polymerase with an initial partitioning of ancestral WASP functions in development and subsequent acquisition of a new function in cell motility during evolution.
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Affiliation(s)
- Klaus Brinkmann
- Institut für Neurobiologie, Universität Münster, Badestr. 9, Münster 48149, Germany
| | - Moritz Winterhoff
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg Strasse 1, Hannover 30625, Germany
| | - Susanne-Filiz Önel
- Fachbereich Biologie, Entwicklungsbiologie, Philipps-Universität Marburg, Karl-von-Frisch Str. 8, Marburg 35043, Germany
| | - Jörg Schultz
- Center for Computational and Theoretical Biology, Campus Nord and Bioinformatik, Biozentrum, Am Hubland, Universität Würzburg, Würzburg 97074, Germany
| | - Jan Faix
- Institut für Biophysikalische Chemie, Medizinische Hochschule Hannover, Carl-Neuberg Strasse 1, Hannover 30625, Germany
| | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestr. 9, Münster 48149, Germany
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11
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Simiczyjew A, Mazur AJ, Ampe C, Malicka-Błaszkiewicz M, van Troys M, Nowak D. Active invadopodia of mesenchymally migrating cancer cells contain both β and γ cytoplasmic actin isoforms. Exp Cell Res 2015; 339:206-19. [PMID: 26548725 DOI: 10.1016/j.yexcr.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 10/25/2022]
Abstract
Invadopodia are actin-rich protrusions formed by mesenchymally migrating cancer cells. They are mainly composed of actin, actin-associated proteins, integrins and proteins of signaling machineries. These protrusions display focalized proteolytic activity towards the extracellular matrix. It is well known that polymerized (F-)actin is present in these structures, but the nature of the actin isoform has not been studied before. We here show that both cytoplasmic actin isoforms, β- and γ-actin, are present in the invadopodia of MDA-MB-231 breast cancer cells cultured on a 2D-surface, where they colocalize with the invadopodial marker cortactin. Invadopodial structures formed by the cells in a 3D-collagen matrix also contain β- and γ-actin. We demonstrate this using isoform-specific antibodies and expression of fluorescently-tagged actin isoforms. Additionally, using simultaneous expression of differentially tagged β- and γ-actin in cells, we show that the actin isoforms are present together in a single invadopodium. Cells with an increased level of β- or γ-actin, display a similar increase in the number and size of invadopodia in comparison to control cells. Moreover, increasing the level of either actin isoforms also increases invasion velocity.
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Affiliation(s)
- Aleksandra Simiczyjew
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Antonina Joanna Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Maria Malicka-Błaszkiewicz
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Marleen van Troys
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Dorota Nowak
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
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12
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Chen XJ, Squarr AJ, Stephan R, Chen B, Higgins TE, Barry DJ, Martin MC, Rosen MK, Bogdan S, Way M. Ena/VASP proteins cooperate with the WAVE complex to regulate the actin cytoskeleton. Dev Cell 2014; 30:569-84. [PMID: 25203209 PMCID: PMC4165403 DOI: 10.1016/j.devcel.2014.08.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 07/21/2014] [Accepted: 08/01/2014] [Indexed: 01/25/2023]
Abstract
Ena/VASP proteins and the WAVE regulatory complex (WRC) regulate cell motility by virtue of their ability to independently promote actin polymerization. We demonstrate that Ena/VASP and the WRC control actin polymerization in a cooperative manner through the interaction of the Ena/VASP EVH1 domain with an extended proline rich motif in Abi. This interaction increases cell migration and enables VASP to cooperatively enhance WRC stimulation of Arp2/3 complex-mediated actin assembly in vitro in the presence of Rac. Loss of this interaction in Drosophila macrophages results in defects in lamellipodia formation, cell spreading, and redistribution of Ena to the tips of filopodia-like extensions. Rescue experiments of abi mutants also reveals a physiological requirement for the Abi:Ena interaction in photoreceptor axon targeting and oogenesis. Our data demonstrate that the activities of Ena/VASP and the WRC are intimately linked to ensure optimal control of actin polymerization during cell migration and development.
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Affiliation(s)
- Xing Judy Chen
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Anna Julia Squarr
- Institute of Neurobiology, University of Muenster, Badestrasse 9, 48149 Muenster, Germany
| | - Raiko Stephan
- Institute of Neurobiology, University of Muenster, Badestrasse 9, 48149 Muenster, Germany
| | - Baoyu Chen
- Howard Hughes Medical Institute and Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Theresa E Higgins
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - David J Barry
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Morag C Martin
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Michael K Rosen
- Howard Hughes Medical Institute and Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sven Bogdan
- Institute of Neurobiology, University of Muenster, Badestrasse 9, 48149 Muenster, Germany.
| | - Michael Way
- Cell Motility Laboratory, London Research Institute, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.
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13
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Rebollo E, Karkali K, Mangione F, Martín-Blanco E. Live imaging in Drosophila: The optical and genetic toolkits. Methods 2014; 68:48-59. [PMID: 24814031 DOI: 10.1016/j.ymeth.2014.04.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 04/27/2014] [Accepted: 04/28/2014] [Indexed: 11/19/2022] Open
Abstract
Biological imaging based on light microscopy comes at the core of the methods that let us understanding morphology and its dynamics in synergy to the spatiotemporal distribution of cellular and molecular activities as the organism develops and becomes functional. Non-linear optical tools and superesolution methodologies are under constant development and their applications to live imaging of whole organisms keep improving as we speak. Genetically coded biosensors, multicolor clonal methods and optogenetics in different organisms and, in particular, in Drosophila follow equivalent paths. We anticipate a brilliant future for live imaging providing the roots for the holistic understanding, rather than for individual parts, of development and function at the whole-organism level.
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Affiliation(s)
- Elena Rebollo
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Katerina Karkali
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Federica Mangione
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Cientific de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.
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14
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Chen B, Brinkmann K, Chen Z, Pak CW, Liao Y, Shi S, Henry L, Grishin NV, Bogdan S, Rosen MK. The WAVE regulatory complex links diverse receptors to the actin cytoskeleton. Cell 2014; 156:195-207. [PMID: 24439376 DOI: 10.1016/j.cell.2013.11.048] [Citation(s) in RCA: 206] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 09/06/2013] [Accepted: 11/25/2013] [Indexed: 02/02/2023]
Abstract
The WAVE regulatory complex (WRC) controls actin cytoskeletal dynamics throughout the cell by stimulating the actin-nucleating activity of the Arp2/3 complex at distinct membrane sites. However, the factors that recruit the WRC to specific locations remain poorly understood. Here, we have identified a large family of potential WRC ligands, consisting of ∼120 diverse membrane proteins, including protocadherins, ROBOs, netrin receptors, neuroligins, GPCRs, and channels. Structural, biochemical, and cellular studies reveal that a sequence motif that defines these ligands binds to a highly conserved interaction surface of the WRC formed by the Sra and Abi subunits. Mutating this binding surface in flies resulted in defects in actin cytoskeletal organization and egg morphology during oogenesis, leading to female sterility. Our findings directly link diverse membrane proteins to the WRC and actin cytoskeleton and have broad physiological and pathological ramifications in metazoans.
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Affiliation(s)
- Baoyu Chen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Klaus Brinkmann
- Institut für Neurobiologie, Universität Münster, 48149 Münster, Germany
| | - Zhucheng Chen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Chi W Pak
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Yuxing Liao
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Shuoyong Shi
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Lisa Henry
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Nick V Grishin
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, 48149 Münster, Germany.
| | - Michael K Rosen
- Department of Biophysics and Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
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15
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Lammel U, Bechtold M, Risse B, Berh D, Fleige A, Bunse I, Jiang X, Klämbt C, Bogdan S. The Drosophila FHOD1-like formin Knittrig acts through Rok to promote stress fiber formation and directed macrophage migration during the cellular immune response. Development 2014; 141:1366-80. [PMID: 24553290 DOI: 10.1242/dev.101352] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A tight spatiotemporal control of actin polymerization is important for many cellular processes that shape cells into a multicellular organism. The formation of unbranched F-actin is induced by several members of the formin family. Drosophila encodes six formin genes, representing six of the seven known mammalian subclasses. Knittrig, the Drosophila homolog of mammalian FHOD1, is specifically expressed in the developing central nervous system midline glia, the trachea, the wing and in macrophages. knittrig mutants exhibit mild tracheal defects but survive until late pupal stages and mainly die as pharate adult flies. knittrig mutant macrophages are smaller and show reduced cell spreading and cell migration in in vivo wounding experiments. Rescue experiments further demonstrate a cell-autonomous function of Knittrig in regulating actin dynamics and cell migration. Knittrig localizes at the rear of migrating macrophages in vivo, suggesting a cellular requirement of Knittrig in the retraction of the trailing edge. Supporting this notion, we found that Knittrig is a target of the Rho-dependent kinase Rok. Co-expression with Rok or expression of an activated form of Knittrig induces actin stress fibers in macrophages and in epithelial tissues. Thus, we propose a model in which Rok-induced phosphorylation of residues within the basic region mediates the activation of Knittrig in controlling macrophage migration.
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Affiliation(s)
- Uwe Lammel
- Institute for Neurobiology, University of Münster, 48149 Münster, Germany
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16
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Hudson AM, Cooley L. Methods for studying oogenesis. Methods 2014; 68:207-17. [PMID: 24440745 DOI: 10.1016/j.ymeth.2014.01.005] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 01/02/2014] [Indexed: 12/31/2022] Open
Abstract
Drosophila oogenesis is an excellent system for the study of developmental cell biology. Active areas of research include stem cell maintenance, gamete development, pattern formation, cytoskeletal regulation, intercellular communication, intercellular transport, cell polarity, cell migration, cell death, morphogenesis, cell cycle control, and many more. The large size and relatively simple organization of egg chambers make them ideally suited for microscopy of both living and fixed whole mount tissue. A wide range of tools is available for oogenesis research. Newly available shRNA transgenic lines provide an alternative to classic loss-of-function F2 screens and clonal screens. Gene expression can be specifically controlled in either germline or somatic cells using the Gal4/UAS system. Protein trap lines provide fluorescent tags of proteins expressed at endogenous levels for live imaging and screening backgrounds. This review provides information on many available reagents and key methods for research in oogenesis.
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Affiliation(s)
- Andrew M Hudson
- Department of Genetics, Yale University School of Medicine, United States
| | - Lynn Cooley
- Department of Genetics, Yale University School of Medicine, United States; Department of Cell Biology, Yale University School of Medicine, United States; Department of Molecular, Cellular & Developmental Biology, Yale University, United States.
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17
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Sander M, Squarr AJ, Risse B, Jiang X, Bogdan S. Drosophila pupal macrophages--a versatile tool for combined ex vivo and in vivo imaging of actin dynamics at high resolution. Eur J Cell Biol 2013; 92:349-54. [PMID: 24183239 DOI: 10.1016/j.ejcb.2013.09.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/20/2013] [Accepted: 09/23/2013] [Indexed: 12/21/2022] Open
Abstract
Molecular understanding of actin dynamics requires a genetically traceable model system that allows live cell imaging together with high-resolution microscopy techniques. Here, we used Drosophila pupal macrophages that combine many advantages of cultured cells with a genetic in vivo model system. Using structured illumination microscopy together with advanced spinning disk confocal microscopy we show that these cells provide a powerful system for single gene analysis. It allows forward genetic screens to characterize the regulatory network controlling cell shape and directed cell migration in a physiological context. We knocked down components regulating lamellipodia formation, including WAVE, single subunits of Arp2/3 complex and CPA, one of the two capping protein subunits and demonstrate the advantages of this model system by imaging mutant macrophages ex vivo as well as in vivo upon laser-induced wounding.
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Affiliation(s)
- Moritz Sander
- Institute for Neurobiology, University of Münster, Germany
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18
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Chacko JV, Zanacchi FC, Diaspro A. Probing cytoskeletal structures by coupling optical superresolution and AFM techniques for a correlative approach. Cytoskeleton (Hoboken) 2013; 70:729-40. [PMID: 24027190 PMCID: PMC4265841 DOI: 10.1002/cm.21139] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 08/28/2013] [Accepted: 09/01/2013] [Indexed: 01/14/2023]
Abstract
In this article, we describe and show the application of some of the most advanced fluorescence superresolution techniques, STED AFM and STORM AFM microscopy towards imaging of cytoskeletal structures, such as microtubule filaments. Mechanical and structural properties can play a relevant role in the investigation of cytoskeletal structures of interest, such as microtubules, that provide support to the cell structure. In fact, the mechanical properties, such as the local stiffness and the elasticity, can be investigated by AFM force spectroscopy with tens of nanometers resolution. Force curves can be analyzed in order to obtain the local elasticity (and the Young's modulus calculation by fitting the force curves from every pixel of interest), and the combination with STED/STORM microscopy integrates the measurement with high specificity and yields superresolution structural information. This hybrid modality of superresolution-AFM working is a clear example of correlative multimodal microscopy.
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Affiliation(s)
- Jenu Varghese Chacko
- Nanophysics, Istituto Italiano di Tecnologia, Genova, Italy; Dipartimento di Fisica, Università degli Studi di Genova, Genova, Italy
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