1
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Sun X, Decker J, Sanchez-Luege N, Rebay I. Inter-plane feedback coordinates cell morphogenesis and maintains 3D tissue organization in the Drosophila pupal retina. Development 2024; 151:dev201757. [PMID: 38533736 PMCID: PMC11006395 DOI: 10.1242/dev.201757] [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: 03/07/2023] [Accepted: 01/12/2024] [Indexed: 03/28/2024]
Abstract
How complex organs coordinate cellular morphogenetic events to achieve three-dimensional (3D) form is a central question in development. The question is uniquely tractable in the late Drosophila pupal retina, where cells maintain stereotyped contacts as they elaborate the specialized cytoskeletal structures that pattern the apical, basal and longitudinal planes of the epithelium. In this study, we combined cell type-specific genetic manipulation of the cytoskeletal regulator Abelson (Abl) with 3D imaging to explore how the distinct cellular morphogenetic programs of photoreceptors and interommatidial pigment cells (IOPCs) organize tissue pattern to support retinal integrity. Our experiments show that photoreceptor and IOPC terminal differentiation is unexpectedly interdependent, connected by an intercellular feedback mechanism that coordinates and promotes morphogenetic change across orthogonal tissue planes to ensure correct 3D retinal pattern. We propose that genetic regulation of specialized cellular differentiation programs combined with inter-plane mechanical feedback confers spatial coordination to achieve robust 3D tissue morphogenesis.
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Affiliation(s)
- Xiao Sun
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Jacob Decker
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Nicelio Sanchez-Luege
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Ilaria Rebay
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637, USA
- Ben May Department for Cancer Research, University of Chicago, Chicago, IL 60637, USA
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2
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Fang HY, Forghani R, Clarke A, McQueen PG, Chandrasekaran A, O’Neill KM, Losert W, Papoian GA, Giniger E. Enabled primarily controls filopodial morphology, not actin organization, in the TSM1 growth cone in Drosophila. Mol Biol Cell 2023; 34:ar83. [PMID: 37223966 PMCID: PMC10398877 DOI: 10.1091/mbc.e23-01-0003] [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: 01/04/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/25/2023] Open
Abstract
Ena/VASP proteins are processive actin polymerases that are required throughout animal phylogeny for many morphogenetic processes, including axon growth and guidance. Here we use in vivo live imaging of morphology and actin distribution to determine the role of Ena in promoting the growth of the TSM1 axon of the Drosophila wing. Altering Ena activity causes stalling and misrouting of TSM1. Our data show that Ena has a substantial impact on filopodial morphology in this growth cone but exerts only modest effects on actin distribution. This is in contrast to the main regulator of Ena, Abl tyrosine kinase, which was shown previously to have profound effects on actin and only mild effects on TSM1 growth cone morphology. We interpret these data as suggesting that the primary role of Ena in this axon may be to link actin to the morphogenetic processes of the plasma membrane, rather than to regulate actin organization itself. These data also suggest that a key role of Ena, acting downstream of Abl, may be to maintain consistent organization and reliable evolution of growth cone structure, even as Abl activity varies in response to guidance cues in the environment.
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Affiliation(s)
- Hsiao Yu Fang
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Rameen Forghani
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Akanni Clarke
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Philip G. McQueen
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
| | - Aravind Chandrasekaran
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20752
| | - Kate M. O’Neill
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
- Institute for Physical Sciences and Department of Physics, University of Maryland, College Park, MD 20752
| | - Wolfgang Losert
- Institute for Physical Sciences and Department of Physics, University of Maryland, College Park, MD 20752
| | - Garegin A. Papoian
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20752
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892
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3
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Sun X, Decker J, Sanchez-Luege N, Rebay I. Orthogonal coupling of a 3D cytoskeletal scaffold coordinates cell morphogenesis and maintains tissue organization in the Drosophila pupal retina. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531386. [PMID: 36945525 PMCID: PMC10028844 DOI: 10.1101/2023.03.06.531386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
How complex three-dimensional (3D) organs coordinate cellular morphogenetic events to achieve the correct final form is a central question in development. The question is uniquely tractable in the late Drosophila pupal retina where cells maintain stereotyped contacts as they elaborate the specialized cytoskeletal structures that pattern the apical, basal and longitudinal planes of the epithelium. In this study, we combined cell type-specific genetic manipulation of the cytoskeletal regulator Abelson (Abl) with 3D imaging to explore how the distinct cellular morphogenetic programs of photoreceptors and interommatidial pigment cells coordinately organize tissue pattern to support retinal integrity. Our experiments revealed an unanticipated intercellular feedback mechanism whereby correct cellular differentiation of either cell type can non-autonomously induce cytoskeletal remodeling in the other Abl mutant cell type, restoring retinal pattern and integrity. We propose that genetic regulation of specialized cellular differentiation programs combined with inter-plane mechanical feedback confers spatial coordination to achieve robust 3D tissue morphogenesis.
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4
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Na S, Cui H, Guo Z, Liang X, Sakran KA, Guo X, Li X, Xie L, Zhu Y, Qi H, Tu J. Overexpression of Mena is associated with tumor progression and poor prognosis in oral squamous cell carcinoma via EMT. Front Oncol 2022; 12:1052375. [PMID: 36620546 PMCID: PMC9822539 DOI: 10.3389/fonc.2022.1052375] [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: 09/23/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Background Mena, a cytoskeletal regulatory protein, is involved in actin-based regulation of cell motility and adhesion, and contributes to tumor invasion and metastasis. However, the role of Mena in oral squamous cell carcinoma remains unclear. This is the first research focusing on the prognostic value of Mena in OSCC. In this study, we aimed to investigate the correlation between Mena expression and clinicopathological significance, as well as prognostic value in OSCC. Methods Mena gene expression profiles of OSCC and normal tissues were collected from Oncomine, TCGA, and GEO databases. Biological function was analyzed through GO, KEGG and GSEA enrichment. Further, the expression level of Mena and tumor-related markers in 151 OSCC specimens was examined by IHC staining based on tissue microarray. Kaplan-Meier analysis was used to assess the prognostic performance of Mena in OSCC. Result Mena was generally upregulation in various malignancies, especially OSCC. The functional analyses indicated that Mena was involved in the assembly and regulation of actin, cell movement, and EMT. IHC staining revealed that high expression of Mena in OSCC was correlated with Lymphatic metastasis, TNM stage, E-cadherin, Vimentin, and MMP-2, but insignificantly Ki67. Kaplan-Meier analysis demonstrated that elevated expression of Mena was significantly associated with poor overall survival and disease-free survival of OSCC patients. Conclusion Mena could be a novel biomarker for predicting the prognosis of OSCC patients, which supports a theoretical basis for developing molecular target therapy.
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Affiliation(s)
- Sijia Na
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Hao Cui
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Zhichen Guo
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Xiang Liang
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Karim Ahmed Sakran
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China,Department of Oral and Maxillofacial Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Xiaomei Guo
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Pathology, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Xingqiang Li
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Linyang Xie
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Yifei Zhu
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China
| | - Hong Qi
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Pathology, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,*Correspondence: Hong Qi, ; Junbo Tu,
| | - Junbo Tu
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, China,*Correspondence: Hong Qi, ; Junbo Tu,
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5
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Faix J, Rottner K. Ena/VASP proteins in cell edge protrusion, migration and adhesion. J Cell Sci 2022; 135:274697. [DOI: 10.1242/jcs.259226] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
ABSTRACT
The tightly coordinated, spatiotemporal control of actin filament remodeling provides the basis of fundamental cellular processes, such as cell migration and adhesion. Specific protein assemblies, composed of various actin-binding proteins, are thought to operate in these processes to nucleate and elongate new filaments, arrange them into complex three-dimensional (3D) arrays and recycle them to replenish the actin monomer pool. Actin filament assembly is not only necessary to generate pushing forces against the leading edge membrane or to propel pathogens through the cytoplasm, but also coincides with the generation of stress fibers (SFs) and focal adhesions (FAs) that generate, transmit and sense mechanical tension. The only protein families known to date that directly enhance the elongation of actin filaments are formins and the family of Ena/VASP proteins. Their mechanisms of action, however, in enhancing processive filament elongation are distinct. The aim of this Review is to summarize our current knowledge on the molecular mechanisms of Ena/VASP-mediated actin filament assembly, and to discuss recent insights into the cell biological functions of Ena/VASP proteins in cell edge protrusion, migration and adhesion.
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Affiliation(s)
- Jan Faix
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Molecular Cell Biology Group, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
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6
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Ecovoiu AA, Ratiu AC, Micheu MM, Chifiriuc MC. Inter-Species Rescue of Mutant Phenotype—The Standard for Genetic Analysis of Human Genetic Disorders in Drosophila melanogaster Model. Int J Mol Sci 2022; 23:ijms23052613. [PMID: 35269756 PMCID: PMC8909942 DOI: 10.3390/ijms23052613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/23/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Drosophila melanogaster (the fruit fly) is arguably a superstar of genetics, an astonishing versatile experimental model which fueled no less than six Nobel prizes in medicine. Nowadays, an evolving research endeavor is to simulate and investigate human genetic diseases in the powerful D. melanogaster platform. Such a translational experimental strategy is expected to allow scientists not only to understand the molecular mechanisms of the respective disorders but also to alleviate or even cure them. In this regard, functional gene orthology should be initially confirmed in vivo by transferring human or vertebrate orthologous transgenes in specific mutant backgrounds of D. melanogaster. If such a transgene rescues, at least partially, the mutant phenotype, then it qualifies as a strong candidate for modeling the respective genetic disorder in the fruit fly. Herein, we review various examples of inter-species rescue of relevant mutant phenotypes of the fruit fly and discuss how these results recommend several human genes as candidates to study and validate genetic variants associated with human diseases. We also consider that a wider implementation of this evolutionist exploratory approach as a standard for the medicine of genetic disorders would allow this particular field of human health to advance at a faster pace.
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Affiliation(s)
- Alexandru Al. Ecovoiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
| | - Attila Cristian Ratiu
- Department of Genetics, Faculty of Biology, University of Bucharest, 060101 Bucharest, Romania;
- Correspondence: ; Tel.: +40-722250366
| | - Miruna Mihaela Micheu
- Department of Cardiology, Clinical Emergency Hospital of Bucharest, 014461 Bucharest, Romania;
| | - Mariana Carmen Chifiriuc
- The Research Institute of the University of Bucharest and Faculty of Biology, University of Bucharest, 050095 Bucharest, Romania;
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7
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Grintsevich EE, Ahmed G, Ginosyan AA, Wu H, Rich SK, Reisler E, Terman JR. Profilin and Mical combine to impair F-actin assembly and promote disassembly and remodeling. Nat Commun 2021; 12:5542. [PMID: 34545088 PMCID: PMC8452626 DOI: 10.1038/s41467-021-25781-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/24/2021] [Indexed: 11/30/2022] Open
Abstract
Cellular events require the spatiotemporal interplay between actin assembly and actin disassembly. Yet, how different factors promote the integration of these two opposing processes is unclear. In particular, cellular monomeric (G)-actin is complexed with profilin, which inhibits spontaneous actin nucleation but fuels actin filament (F-actin) assembly by elongation-promoting factors (formins, Ena/VASP). In contrast, site-specific F-actin oxidation by Mical promotes F-actin disassembly and release of polymerization-impaired Mical-oxidized (Mox)-G-actin. Here we find that these two opposing processes connect with one another to orchestrate actin/cellular remodeling. Specifically, we find that profilin binds Mox-G-actin, yet these complexes do not fuel elongation factors’-mediated F-actin assembly, but instead inhibit polymerization and promote further Mox-F-actin disassembly. Using Drosophila as a model system, we show that similar profilin–Mical connections occur in vivo – where they underlie F-actin/cellular remodeling that accompanies Semaphorin–Plexin cellular/axon repulsion. Thus, profilin and Mical combine to impair F-actin assembly and promote F-actin disassembly, while concomitantly facilitating cellular remodeling and plasticity. Actin-based structures in cells and tissues are built and maintained through a poorly understood balance between assembly and disassembly. Here, our findings provide insights into how factors known to promote these opposing effects dynamically integrate to shape cells and tissue systems.
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Affiliation(s)
- Elena E Grintsevich
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA. .,Department of Chemistry and Biochemistry, California State University, Long Beach (CSULB), Long Beach, CA, 90840, USA.
| | - Giasuddin Ahmed
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Anush A Ginosyan
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA
| | - Heng Wu
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Shannon K Rich
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Emil Reisler
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095, USA. .,Molecular Biology Institute, UCLA, Los Angeles, CA, 90095, USA.
| | - Jonathan R Terman
- Departments of Neuroscience and Pharmacology, The University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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8
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Davidson AJ, Wood W. Macrophages Use Distinct Actin Regulators to Switch Engulfment Strategies and Ensure Phagocytic Plasticity In Vivo. Cell Rep 2021; 31:107692. [PMID: 32460022 PMCID: PMC7262594 DOI: 10.1016/j.celrep.2020.107692] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 04/16/2020] [Accepted: 05/05/2020] [Indexed: 01/02/2023] Open
Abstract
Macrophages must not only be responsive to an array of different stimuli, such as infection and cellular damage, but also perform phagocytosis within the diverse and complex tissue environments found in vivo. This requires a high degree of morphological and therefore cytoskeletal plasticity. Here, we use the exceptional genetics and in vivo imaging of Drosophila embryos to study macrophage phagocytic versatility during apoptotic corpse clearance. We find that macrophage phagocytosis is highly robust, arising from their possession of two distinct modes of engulfment that utilize exclusive suites of actin-regulatory proteins. “Lamellipodial phagocytosis” is Arp2/3-complex-dependent and allows cells to migrate toward and envelop apoptotic corpses. Alternatively, Diaphanous and Ena drive filopodial phagocytosis to reach out and draw in debris. Macrophages switch to “filopodial phagocytosis” to overcome spatial constraint, providing the robust plasticity necessary to ensure that whatever obstacle they encounter in vivo, they fulfil their critical clearance function. Macrophages use two distinct modes of engulfment: lamellipodial and filopodial phagocytosis Arp2/3-complex-dependent lamellipodial phagocytosis involves envelopment via a lamellipod Filopodial phagocytosis involves phagocytic filopods extended by Dia and/or Ena Macrophages switch to filopodial phagocytosis to overcome spatial constraint in vivo
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Affiliation(s)
- Andrew J Davidson
- Centre for Inflammation Research, University of Edinburgh, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK
| | - Will Wood
- Centre for Inflammation Research, University of Edinburgh, Queens Medical Research Institute, 47 Little France Crescent, Edinburgh EH16 4TJ, UK.
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9
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King TR, Kramer J, Cheng YS, Swope D, Kramer SG. Enabled/VASP is required to mediate proper sealing of opposing cardioblasts during Drosophila dorsal vessel formation. Dev Dyn 2021; 250:1173-1190. [PMID: 33587326 DOI: 10.1002/dvdy.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/16/2021] [Accepted: 02/02/2021] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION The Drosophila dorsal vessel (DV) is comprised of two opposing rows of cardioblasts (CBs) that migrate toward the dorsal midline during development. While approaching the midline, CBs change shape, enabling dorsal and ventral attachments with their contralateral partners to create a linear tube with a central lumen. We previously demonstrated DV closure occurs via a "buttoning" mechanism where specific CBs advance ahead of their lateral neighbors, and attach creating transient holes, which eventually seal. RESULTS Here, we investigate the role of the actin-regulatory protein enabled (Ena) in DV closure. Loss of Ena results in DV cell shape and alignment defects. Live analysis of DV formation in ena mutants shows a reduction in CB leading edge protrusion length and gaps in the DV between contralateral CB pairs. These gaps occur primarily between a specific genetic subtype of CBs, which express the transcription factor seven-up (Svp) and form the ostia inflow tracts of the heart. In WT embryos these gaps between Svp+ CBs are observed transiently during the final stages of DV closure. CONCLUSIONS Our data suggest that Ena modulates the actin cytoskeleton in order to facilitate the complete sealing of the DV during the final stages of cardiac tube formation.
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Affiliation(s)
- Tiffany R King
- Graduate Program in Cell and Developmental Biology, Rutgers Graduate School of Biomedical Sciences at Robert Wood Johnson Medical School, Department of Pathology and Laboratory Medicine, Piscataway, New Jersey, USA.,Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Joseph Kramer
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Yi-Shan Cheng
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - David Swope
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA.,Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Sunita G Kramer
- Department of Pathology and Laboratory Medicine, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
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10
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Hildebrand JD, Leventry AD, Aideyman OP, Majewski JC, Haddad JA, Bisi DC, Kaufmann N. A modifier screen identifies regulators of cytoskeletal architecture as mediators of Shroom-dependent changes in tissue morphology. Biol Open 2021; 10:bio.055640. [PMID: 33504488 PMCID: PMC7875558 DOI: 10.1242/bio.055640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Regulation of cell architecture is critical in the formation of tissues during animal development. The mechanisms that control cell shape must be both dynamic and stable in order to establish and maintain the correct cellular organization. Previous work has identified Shroom family proteins as essential regulators of cell morphology during vertebrate development. Shroom proteins regulate cell architecture by directing the subcellular distribution and activation of Rho-kinase, which results in the localized activation of non-muscle myosin II. Because the Shroom-Rock-myosin II module is conserved in most animal model systems, we have utilized Drosophila melanogaster to further investigate the pathways and components that are required for Shroom to define cell shape and tissue architecture. Using a phenotype-based heterozygous F1 genetic screen for modifiers of Shroom activity, we identified several cytoskeletal and signaling protein that may cooperate with Shroom. We show that two of these proteins, Enabled and Short stop, are required for ShroomA-induced changes in tissue morphology and are apically enriched in response to Shroom expression. While the recruitment of Ena is necessary, it is not sufficient to redefine cell morphology. Additionally, this requirement for Ena appears to be context dependent, as a variant of Shroom that is apically localized, binds to Rock, but lacks the Ena binding site, is still capable of inducing changes in tissue architecture. These data point to important cellular pathways that may regulate contractility or facilitate Shroom-mediated changes in cell and tissue morphology. Summary: Using Drosophila as a model system, we identify F-actin and microtubules as important determinants of how cells and tissues respond to Shroom induced contractility.
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Affiliation(s)
- Jeffrey D Hildebrand
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Adam D Leventry
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Omoregie P Aideyman
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - John C Majewski
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - James A Haddad
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Dawn C Bisi
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Nancy Kaufmann
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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11
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Platenkamp A, Detmar E, Sepulveda L, Ritz A, Rogers SL, Applewhite DA. The Drosophila melanogaster Rab GAP RN-tre cross-talks with the Rho1 signaling pathway to regulate nonmuscle myosin II localization and function. Mol Biol Cell 2020; 31:2379-2397. [PMID: 32816624 PMCID: PMC7851959 DOI: 10.1091/mbc.e20-03-0181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
To identify novel regulators of nonmuscle myosin II (NMII) we performed an image-based RNA interference screen using stable Drosophila melanogaster S2 cells expressing the enhanced green fluorescent protein (EGFP)-tagged regulatory light chain (RLC) of NMII and mCherry-Actin. We identified the Rab-specific GTPase-activating protein (GAP) RN-tre as necessary for the assembly of NMII RLC into contractile actin networks. Depletion of RN-tre led to a punctate NMII phenotype, similar to what is observed following depletion of proteins in the Rho1 pathway. Depletion of RN-tre also led to a decrease in active Rho1 and a decrease in phosphomyosin-positive cells by immunostaining, while expression of constitutively active Rho or Rho-kinase (Rok) rescues the punctate phenotype. Functionally, RN-tre depletion led to an increase in actin retrograde flow rate and cellular contractility in S2 and S2R+ cells, respectively. Regulation of NMII by RN-tre is only partially dependent on its GAP activity as overexpression of constitutively active Rabs inactivated by RN-tre failed to alter NMII RLC localization, while a GAP-dead version of RN-tre partially restored phosphomyosin staining. Collectively, our results suggest that RN-tre plays an important regulatory role in NMII RLC distribution, phosphorylation, and function, likely through Rho1 signaling and putatively serving as a link between the secretion machinery and actomyosin contractility.
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Affiliation(s)
| | - Elizabeth Detmar
- Department of Biology & Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
| | - Liz Sepulveda
- Department of Biology, Reed College, Portland, OR 97202
| | - Anna Ritz
- Department of Biology, Reed College, Portland, OR 97202
| | - Stephen L Rogers
- Department of Biology & Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280
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12
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Chen X, Yuan XN, Zhang Z, Gong PJ, Yin WN, Jiang Q, Xu J, Xu XL, Gao Y, Chen WL, Chen FF, Tian YH, Wei L, Zhang JW. Betulinic acid inhibits cell proliferation and migration in gastric cancer by targeting the NF-κB/VASP pathway. Eur J Pharmacol 2020; 889:173493. [PMID: 32860808 DOI: 10.1016/j.ejphar.2020.173493] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 08/11/2020] [Accepted: 08/19/2020] [Indexed: 01/06/2023]
Abstract
Gastric cancer (GC) is one of the most common malignant neoplasms of the digestive system, with China leading in terms of morbidity and mortality rates. Betulinic acid (BA) is a widely-occurring pentacyclic triterpenoid that has been reported to exhibit potent anti-inflammatory, antioxidant, and antitumor activities. BA can combat tumors by inducing apoptosis, regulating cell cycle, and inhibiting autophagy, but its mechanism of action in the context of GC is unclear. A preliminary study found that higher expression of vasodilator-stimulated phosphoprotein (VASP) was correlated with migration in the GC cell line. In this study, BGC-823 cells and MNK45 cells were treated with BA for investigating its effect on the proliferation and migration of cells. Moreover, the expression of VASP and upstream signal molecules were also investigated in this background. The results showed BA could inhibit the proliferation and migration the GC cells. Furthermore, NF-κB acted as a transcription factor to upregulate VASP expression. Moreover, BA could downregulate the expression of VASP at the protein and mRNA level by inhibiting NF-κB activity. In conclusion, these results suggest that BA could inhibit the expression of VASP by negatively regulating NF-κB, thereby inhibiting the proliferation and migration of the GC cells. Our study provides a theoretical basis for exploring the molecular mechanism underlying BA-induced inhibition of proliferation and migration in GC cells.
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Affiliation(s)
- Xiang Chen
- Department of Breast and Thyroid Surgery, Zhongnan Hospital, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China; Department of Pathology, Central Theater Command General Hospital, People's Liberation Army of China, Wuhan, 430070, Hubei, China
| | - Xiao-Ning Yuan
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Zun Zhang
- Department of Breast and Thyroid Surgery, Renmin Hospital, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China
| | - Peng-Ju Gong
- Department of Breast and Thyroid Surgery, Zhongnan Hospital, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China
| | - Wei-Nan Yin
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Qi Jiang
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Jingjing Xu
- Department of Breast and Thyroid Surgery, Zhongnan Hospital, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China
| | - Xiao-Long Xu
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Yang Gao
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Wen-Li Chen
- Division of Nephrology, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430014, Hubei, China
| | - Fang-Fang Chen
- Department of Breast and Thyroid Surgery, Zhongnan Hospital, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China
| | - Yi-Hao Tian
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Lei Wei
- Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, Hubei, China
| | - Jing-Wei Zhang
- Department of Breast and Thyroid Surgery, Zhongnan Hospital, Hubei Key Laboratory of Tumor Biological Behaviors, Hubei Cancer Clinical Study Center, Wuhan University, Wuhan, 430071, Hubei, China.
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13
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Cheong HSJ, Nona M, Guerra SB, VanBerkum MF. The first quarter of the C-terminal domain of Abelson regulates the WAVE regulatory complex and Enabled in axon guidance. Neural Dev 2020; 15:7. [PMID: 32359359 PMCID: PMC7196227 DOI: 10.1186/s13064-020-00144-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/17/2020] [Indexed: 12/16/2022] Open
Abstract
Background Abelson tyrosine kinase (Abl) plays a key role in axon guidance in linking guidance receptors to actin dynamics. The long C-terminal domain (CTD) of Drosophila Abl is important for this role, and previous work identified the ‘first quarter’ (1Q) of the CTD as essential. Here, we link the physical interactions of 1Q binding partners to Abl’s function in axon guidance. Methods Protein binding partners of 1Q were identified by GST pulldown and mass spectrometry, and validated using axon guidance assays in the embryonic nerve cord and motoneurons. The role of 1Q was assessed genetically, utilizing a battery of Abl transgenes in combination with mutation or overexpression of the genes of pulled down proteins, and their partners in actin dynamics. The set of Abl transgenes had the following regions deleted: all of 1Q, each half of 1Q (‘eighths’, 1E and 2E) or a PxxP motif in 2E, which may bind SH3 domains. Results GST pulldown identified Hem and Sra-1 as binding partners of 1Q, and our genetic analyses show that both proteins function with Abl in axon guidance, with Sra-1 likely interacting with 1Q. As Hem and Sra-1 are part of the actin-polymerizing WAVE regulatory complex (WRC), we extended our analyses to Abi and Trio, which interact with Abl and WRC members. Overall, the 1Q region (and especially 2E and its PxxP motif) are important for Abl’s ability to work with WRC in axon guidance. These areas are also important for Abl’s ability to function with the actin regulator Enabled. In comparison, 1E contributes to Abl function with the WRC at the midline, but less so with Enabled. Conclusions The 1Q region, and especially the 2E region with its PxxP motif, links Abl with the WRC, its regulators Trio and Abi, and the actin regulator Ena. Removing 1E has specific effects suggesting it may help modulate Abl’s interaction with the WRC or Ena. Thus, the 1Q region of Abl plays a key role in regulating actin dynamics during axon guidance.
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Affiliation(s)
| | - Mark Nona
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
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14
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McNeill EM, Thompson C, Berke B, Chou VT, Rusch J, Duckworth A, DeProto J, Taylor A, Gates J, Gertler F, Keshishian H, Van Vactor D. Drosophila enabled promotes synapse morphogenesis and regulates active zone form and function. Neural Dev 2020; 15:4. [PMID: 32183907 PMCID: PMC7076993 DOI: 10.1186/s13064-020-00141-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 02/25/2020] [Indexed: 11/10/2022] Open
Abstract
Background Recent studies of synapse form and function highlight the importance of the actin cytoskeleton in regulating multiple aspects of morphogenesis, neurotransmission, and neural plasticity. The conserved actin-associated protein Enabled (Ena) is known to regulate development of the Drosophila larval neuromuscular junction through a postsynaptic mechanism. However, the functions and regulation of Ena within the presynaptic terminal has not been determined. Methods Here, we use a conditional genetic approach to address a presynaptic role for Ena on presynaptic morphology and ultrastructure, and also examine the pathway in which Ena functions through epistasis experiments. Results We find that Ena is required to promote the morphogenesis of presynaptic boutons and branches, in contrast to its inhibitory role in muscle. Moreover, while postsynaptic Ena is regulated by microRNA-mediated mechanisms, presynaptic Ena relays the output of the highly conserved receptor protein tyrosine phosphatase Dlar and associated proteins including the heparan sulfate proteoglycan Syndecan, and the non-receptor Abelson tyrosine kinase to regulate addition of presynaptic varicosities. Interestingly, Ena also influences active zones, where it restricts active zone size, regulates the recruitment of synaptic vesicles, and controls the amplitude and frequency of spontaneous glutamate release. Conclusion We thus show that Ena, under control of the Dlar pathway, is required for presynaptic terminal morphogenesis and bouton addition and that Ena has active zone and neurotransmission phenotypes. Notably, in contrast to Dlar, Ena appears to integrate multiple pathways that regulate synapse form and function.
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Affiliation(s)
- Elizabeth M McNeill
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
| | - Cheryl Thompson
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Brett Berke
- Department of Biology, Yale University, New Haven, CT, USA
| | - Vivian T Chou
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
| | - Jannette Rusch
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - April Duckworth
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Jamin DeProto
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Alicia Taylor
- Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.,Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Julie Gates
- Department of Biology, Bucknell University, Lewisburg, PA, USA
| | - Frank Gertler
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, England
| | | | - David Van Vactor
- Department of Cell Biology and Program in Neuroscience, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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15
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Martin AC. The Physical Mechanisms of Drosophila Gastrulation: Mesoderm and Endoderm Invagination. Genetics 2020; 214:543-560. [PMID: 32132154 PMCID: PMC7054018 DOI: 10.1534/genetics.119.301292] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 11/21/2019] [Indexed: 12/14/2022] Open
Abstract
A critical juncture in early development is the partitioning of cells that will adopt different fates into three germ layers: the ectoderm, the mesoderm, and the endoderm. This step is achieved through the internalization of specified cells from the outermost surface layer, through a process called gastrulation. In Drosophila, gastrulation is achieved through cell shape changes (i.e., apical constriction) that change tissue curvature and lead to the folding of a surface epithelium. Folding of embryonic tissue results in mesoderm and endoderm invagination, not as individual cells, but as collective tissue units. The tractability of Drosophila as a model system is best exemplified by how much we know about Drosophila gastrulation, from the signals that pattern the embryo to the molecular components that generate force, and how these components are organized to promote cell and tissue shape changes. For mesoderm invagination, graded signaling by the morphogen, Spätzle, sets up a gradient in transcriptional activity that leads to the expression of a secreted ligand (Folded gastrulation) and a transmembrane protein (T48). Together with the GPCR Mist, which is expressed in the mesoderm, and the GPCR Smog, which is expressed uniformly, these signals activate heterotrimeric G-protein and small Rho-family G-protein signaling to promote apical contractility and changes in cell and tissue shape. A notable feature of this signaling pathway is its intricate organization in both space and time. At the cellular level, signaling components and the cytoskeleton exhibit striking polarity, not only along the apical-basal cell axis, but also within the apical domain. Furthermore, gene expression controls a highly choreographed chain of events, the dynamics of which are critical for primordium invagination; it does not simply throw the cytoskeletal "on" switch. Finally, studies of Drosophila gastrulation have provided insight into how global tissue mechanics and movements are intertwined as multiple tissues simultaneously change shape. Overall, these studies have contributed to the view that cells respond to forces that propagate over great distances, demonstrating that cellular decisions, and, ultimately, tissue shape changes, proceed by integrating cues across an entire embryo.
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Affiliation(s)
- Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142
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16
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Hunter GL, Giniger E. Phosphorylation and Proteolytic Cleavage of Notch in Canonical and Noncanonical Notch Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1227:51-68. [DOI: 10.1007/978-3-030-36422-9_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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The cellular and molecular mechanisms that establish the mechanics of Drosophila gastrulation. Curr Top Dev Biol 2020; 136:141-165. [DOI: 10.1016/bs.ctdb.2019.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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18
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Pharmaco-Genetic Screen To Uncover Actin Regulators Targeted by Prostaglandins During Drosophila Oogenesis. G3-GENES GENOMES GENETICS 2019; 9:3555-3565. [PMID: 31506320 PMCID: PMC6829128 DOI: 10.1534/g3.119.400704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Prostaglandins (PGs) are lipid signaling molecules with numerous physiologic functions, including pain/inflammation, fertility, and cancer. PGs are produced downstream of cyclooxygenase (COX) enzymes, the targets of non-steroidal anti-inflammatory drugs (NSAIDs). In numerous systems, PGs regulate actin cytoskeletal remodeling, however, their mechanisms of action remain largely unknown. To address this deficiency, we undertook a pharmaco-genetic interaction screen during late-stage Drosophila oogenesis. Drosophila oogenesis is as an established model for studying both actin dynamics and PGs. Indeed, during Stage 10B, cage-like arrays of actin bundles surround each nurse cell nucleus, and during Stage 11, the cortical actin contracts, squeezing the cytoplasmic contents into the oocyte. Both of these cytoskeletal properties are required for follicle development and fertility, and are regulated by PGs. Here we describe a pharmaco-genetic interaction screen that takes advantage of the fact that Stage 10B follicles will mature in culture and COX inhibitors, such as aspirin, block this in vitro follicle maturation. In the screen, aspirin was used at a concentration that blocks 50% of the wild-type follicles from maturing in culture. By combining this aspirin treatment with heterozygosity for mutations in actin regulators, we quantitatively identified enhancers and suppressors of COX inhibition. Here we present the screen results and initial follow-up studies on three strong enhancers – Enabled, Capping protein, and non-muscle Myosin II Regulatory Light Chain. Overall, these studies provide new insight into how PGs regulate both actin bundle formation and cellular contraction, properties that are not only essential for development, but are misregulated in disease.
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19
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Davidson AJ, Millard TH, Evans IR, Wood W. Ena orchestrates remodelling within the actin cytoskeleton to drive robust Drosophila macrophage chemotaxis. J Cell Sci 2019; 132:jcs.224618. [PMID: 30718364 PMCID: PMC6432709 DOI: 10.1242/jcs.224618] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 01/15/2019] [Indexed: 01/08/2023] Open
Abstract
The actin cytoskeleton is the engine that powers the inflammatory chemotaxis of immune cells to sites of tissue damage or infection. Here, we combine genetics with live in vivo imaging to investigate how cytoskeletal rearrangements drive macrophage recruitment to wounds in Drosophila. We find that the actin-regulatory protein Ena is a master regulator of lamellipodial dynamics in migrating macrophages, where it remodels the cytoskeleton to form linear filaments that can then be bundled together by the cross-linker Fascin (also known as Singed in flies). In contrast, the formin Dia generates rare, probing filopods for specialised functions that are not required for migration. The role of Ena in lamellipodial bundling is so fundamental that its overexpression increases bundling even in the absence of Fascin by marshalling the remaining cross-linking proteins to compensate. This reorganisation of the lamellipod generates cytoskeletal struts that push against the membrane to drive leading edge advancement and boost cell speed. Thus, Ena-mediated remodelling extracts the most from the cytoskeleton to power robust macrophage chemotaxis during their inflammatory recruitment to wounds. Summary: Macrophages must migrate to a variety of stimuli, including inflammatory wounds. We identify the actin-regulatory protein Ena as a master remodeller of the cytoskeleton within migrating macrophages in vivo.
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Affiliation(s)
- Andrew J Davidson
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Tom H Millard
- Faculty of Biology, Medicine and Health, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Iwan R Evans
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK.,The Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
| | - Will Wood
- School of Cellular and Molecular Medicine, Faculty of Biomedical Sciences, University of Bristol, Bristol BS8 1TD, UK
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20
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Bernardoni R, Giordani G, Signorino E, Monticelli S, Messa F, Pradotto M, Rosso V, Bracco E, Giangrande A, Perini G, Saglio G, Cilloni D. A new BCR-ABL1 Drosophila model as a powerful tool to elucidate the pathogenesis and progression of chronic myeloid leukemia. Haematologica 2018; 104:717-728. [PMID: 30409797 PMCID: PMC6442973 DOI: 10.3324/haematol.2018.198267] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 11/08/2018] [Indexed: 01/10/2023] Open
Abstract
The oncoprotein BCR-ABL1 triggers chronic myeloid leukemia. It is clear that the disease relies on constitutive BCR-ABL1 kinase activity, but not all the interactors and regulators of the oncoprotein are known. We describe and validate a Drosophila leukemia model based on inducible human BCR-ABL1 expression controlled by tissue-specific promoters. The model was conceived to be a versatile tool for performing genetic screens. BCR-ABL1 expression in the developing eye interferes with ommatidia differentiation and expression in the hematopoietic precursors increases the number of circulating blood cells. We show that BCR-ABL1 interferes with the pathway of endogenous dAbl with which it shares the target protein Ena. Loss of function of ena or Dab, an upstream regulator of dAbl, respectively suppresses or enhances both the BCR-ABL1-dependent phenotypes. Importantly, in patients with leukemia decreased human Dab1 and Dab2 expression correlates with more severe disease and Dab1 expression reduces the proliferation of leukemia cells. Globally, these observations validate our Drosophila model, which promises to be an excellent system for performing unbiased genetic screens aimed at identifying new BCR-ABL1 interactors and regulators in order to better elucidate the mechanism of leukemia onset and progression.
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Affiliation(s)
- Roberto Bernardoni
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Italy .,Health Sciences and Technology - Interdepartmental Center for Industrial Research (HST-ICIR), University of Bologna, Ozzano Emilia, Italy
| | - Giorgia Giordani
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Italy.,Department of Clinical and Biological Sciences, University of Turin, Italy.,Present address: Department of Biological Sciences, School of Applied Sciences, University of Huddersfield, Queensgate, UK
| | | | - Sara Monticelli
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Italy
| | - Francesca Messa
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Italy
| | - Monica Pradotto
- Department of Clinical and Biological Sciences, University of Turin, Italy
| | - Valentina Rosso
- Department of Clinical and Biological Sciences, University of Turin, Italy
| | | | - Angela Giangrande
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP 67404 Illkirch, France
| | - Giovanni Perini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Italy.,Health Sciences and Technology - Interdepartmental Center for Industrial Research (HST-ICIR), University of Bologna, Ozzano Emilia, Italy
| | - Giuseppe Saglio
- Department of Clinical and Biological Sciences, University of Turin, Italy
| | - Daniela Cilloni
- Department of Clinical and Biological Sciences, University of Turin, Italy
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21
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Cheong HSJ, VanBerkum MFA. Long disordered regions of the C-terminal domain of Abelson tyrosine kinase have specific and additive functions in regulation and axon localization. PLoS One 2017; 12:e0189338. [PMID: 29232713 PMCID: PMC5726718 DOI: 10.1371/journal.pone.0189338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/22/2017] [Indexed: 01/28/2023] Open
Abstract
Abelson tyrosine kinase (Abl) is a key regulator of actin-related morphogenetic processes including axon guidance, where it functions downstream of several guidance receptors. While the long C-terminal domain (CTD) of Abl is required for function, its role is poorly understood. Here, a battery of mutants of Drosophila Abl was created that systematically deleted large segments of the CTD from Abl or added them back to the N-terminus alone. The functionality of these Abl transgenes was assessed through rescue of axon guidance defects and adult lethality in Abl loss-of-function, as well as through gain-of-function effects in sensitized slit or frazzled backgrounds that perturb midline guidance in the Drosophila embryonic nerve cord. Two regions of the CTD play important and distinct roles, but additive effects for other regions were also detected. The first quarter of the CTD, including a conserved PxxP motif and its surrounding sequence, regulates Abl function while the third quarter localizes Abl to axons. These regions feature long stretches of intrinsically disordered sequence typically found in hub proteins and are associated with diverse protein-protein interactions. Thus, the CTD of Abl appears to use these disordered regions to establish a variety of different signaling complexes required during formation of axon tracts.
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Affiliation(s)
- Han S J Cheong
- Department of Biological Sciences, Wayne State University, Detroit, United States of America
| | - Mark F A VanBerkum
- Department of Biological Sciences, Wayne State University, Detroit, United States of America
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22
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Kannan R, Song JK, Karpova T, Clarke A, Shivalkar M, Wang B, Kotlyanskaya L, Kuzina I, Gu Q, Giniger E. The Abl pathway bifurcates to balance Enabled and Rac signaling in axon patterning in Drosophila. Development 2017; 144:487-498. [PMID: 28087633 DOI: 10.1242/dev.143776] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 12/15/2016] [Indexed: 01/31/2023]
Abstract
The Abl tyrosine kinase signaling network controls cell migration, epithelial organization, axon patterning and other aspects of development. Although individual components are known, the relationships among them remain unresolved. We now use FRET measurements of pathway activity, analysis of protein localization and genetic epistasis to dissect the structure of this network in Drosophila We find that the adaptor protein Disabled stimulates Abl kinase activity. Abl suppresses the actin-regulatory factor Enabled, and we find that Abl also acts through the GEF Trio to stimulate the signaling activity of Rac GTPase: Abl gates the activity of the spectrin repeats of Trio, allowing them to relieve intramolecular repression of Trio GEF activity by the Trio N-terminal domain. Finally, we show that a key target of Abl signaling in axons is the WAVE complex that promotes the formation of branched actin networks. Thus, we show that Abl constitutes a bifurcating network, suppressing Ena activity in parallel with stimulation of WAVE. We suggest that the balancing of linear and branched actin networks by Abl is likely to be central to its regulation of axon patterning.
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Affiliation(s)
- Ramakrishnan Kannan
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jeong-Kuen Song
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tatiana Karpova
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Akanni Clarke
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Madhuri Shivalkar
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Benjamin Wang
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lyudmila Kotlyanskaya
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Irina Kuzina
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Qun Gu
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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23
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Rogers EM, Spracklen AJ, Bilancia CG, Sumigray KD, Allred SC, Nowotarski SH, Schaefer KN, Ritchie BJ, Peifer M. Abelson kinase acts as a robust, multifunctional scaffold in regulating embryonic morphogenesis. Mol Biol Cell 2016; 27:2613-31. [PMID: 27385341 PMCID: PMC4985262 DOI: 10.1091/mbc.e16-05-0292] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/20/2016] [Indexed: 11/16/2022] Open
Abstract
The importance of Abl kinase activity, the F-actin–binding site, and scaffolding ability in Abl’s many cell biological roles during Drosophila morphogenesis is examined. Abl is a robust multidomain scaffold with different protein motifs and activities contributing differentially to diverse cellular behaviors. Abelson family kinases (Abls) are key regulators of cell behavior and the cytoskeleton during development and in leukemia. Abl’s SH3, SH2, and tyrosine kinase domains are joined via a linker to an F-actin–binding domain (FABD). Research on Abl’s roles in cell culture led to several hypotheses for its mechanism of action: 1) Abl phosphorylates other proteins, modulating their activity, 2) Abl directly regulates the cytoskeleton via its cytoskeletal interaction domains, and/or 3) Abl is a scaffold for a signaling complex. The importance of these roles during normal development remains untested. We tested these mechanistic hypotheses during Drosophila morphogenesis using a series of mutants to examine Abl’s many cell biological roles. Strikingly, Abl lacking the FABD fully rescued morphogenesis, cell shape change, actin regulation, and viability, whereas kinase-dead Abl, although reduced in function, retained substantial rescuing ability in some but not all Abl functions. We also tested the function of four conserved motifs in the linker region, revealing a key role for a conserved PXXP motif known to bind Crk and Abi. We propose that Abl acts as a robust multidomain scaffold with different protein motifs and activities contributing differentially to diverse cellular behaviors.
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Affiliation(s)
- Edward M Rogers
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Andrew J Spracklen
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Colleen G Bilancia
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kaelyn D Sumigray
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - S Colby Allred
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Stephanie H Nowotarski
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Kristina N Schaefer
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Benjamin J Ritchie
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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The E3 Ubiquitin Ligase TRIM9 Is a Filopodia Off Switch Required for Netrin-Dependent Axon Guidance. Dev Cell 2016; 35:698-712. [PMID: 26702829 DOI: 10.1016/j.devcel.2015.11.022] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/09/2015] [Accepted: 10/19/2015] [Indexed: 02/01/2023]
Abstract
Neuronal growth cone filopodia contain guidance receptors and contribute to axon guidance; however, the mechanism by which the guidance cue netrin increases filopodia density is unknown. Here, we demonstrate that TRIM9, an E3 ubiquitin ligase that localizes to filopodia tips and binds the netrin receptor DCC, interacts with and ubiquitinates the barbed-end polymerase VASP to modulate filopodial stability during netrin-dependent axon guidance. Studies with murine Trim9(+/+) and Trim9(-/-) cortical neurons, along with a non-ubiquitinatable VASP mutant, demonstrate that TRIM9-mediated ubiquitination of VASP reduces VASP filopodial tip localization, VASP dynamics at tips, and filopodial stability. Upon netrin treatment, VASP is deubiquitinated, which promotes VASP tip localization and filopodial stability. Trim9 deletion induces axon guidance defects in vitro and in vivo, whereas a gradient of deubiquitinase inhibition promotes axon turning in vitro. We conclude that a gradient of TRIM9-mediated ubiquitination of VASP creates a filopodial stability gradient during axon turning.
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Glypican Is a Modulator of Netrin-Mediated Axon Guidance. PLoS Biol 2015; 13:e1002183. [PMID: 26148345 PMCID: PMC4493048 DOI: 10.1371/journal.pbio.1002183] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/15/2015] [Indexed: 11/19/2022] Open
Abstract
Netrin is a key axon guidance cue that orients axon growth during neural circuit formation. However, the mechanisms regulating netrin and its receptors in the extracellular milieu are largely unknown. Here we demonstrate that in Caenorhabditis elegans, LON-2/glypican, a heparan sulfate proteoglycan, modulates UNC-6/netrin signaling and may do this through interactions with the UNC-40/DCC receptor. We show that developing axons misorient in the absence of LON-2/glypican when the SLT-1/slit guidance pathway is compromised and that LON-2/glypican functions in both the attractive and repulsive UNC-6/netrin pathways. We find that the core LON-2/glypican protein, lacking its heparan sulfate chains, and secreted forms of LON-2/glypican are functional in axon guidance. We also find that LON-2/glypican functions from the epidermal substrate cells to guide axons, and we provide evidence that LON-2/glypican associates with UNC-40/DCC receptor-expressing cells. We propose that LON-2/glypican acts as a modulator of UNC-40/DCC-mediated guidance to fine-tune axonal responses to UNC-6/netrin signals during migration.
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Bearce EA, Erdogan B, Lowery LA. TIPsy tour guides: how microtubule plus-end tracking proteins (+TIPs) facilitate axon guidance. Front Cell Neurosci 2015; 9:241. [PMID: 26175669 PMCID: PMC4485311 DOI: 10.3389/fncel.2015.00241] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 06/15/2015] [Indexed: 01/01/2023] Open
Abstract
The growth cone is a dynamic cytoskeletal vehicle, which drives the end of a developing axon. It serves to interpret and navigate through the complex landscape and guidance cues of the early nervous system. The growth cone’s distinctive cytoskeletal organization offers a fascinating platform to study how extracellular cues can be translated into mechanical outgrowth and turning behaviors. While many studies of cell motility highlight the importance of actin networks in signaling, adhesion, and propulsion, both seminal and emerging works in the field have highlighted a unique and necessary role for microtubules (MTs) in growth cone navigation. Here, we focus on the role of singular pioneer MTs, which extend into the growth cone periphery and are regulated by a diverse family of microtubule plus-end tracking proteins (+TIPs). These +TIPs accumulate at the dynamic ends of MTs, where they are well-positioned to encounter and respond to key signaling events downstream of guidance receptors, catalyzing immediate changes in microtubule stability and actin cross-talk, that facilitate both axonal outgrowth and turning events.
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Affiliation(s)
| | - Burcu Erdogan
- Department of Biology, Boston College Chestnut Hill, MA, USA
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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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Nowotarski SH, McKeon N, Moser RJ, Peifer M. The actin regulators Enabled and Diaphanous direct distinct protrusive behaviors in different tissues during Drosophila development. Mol Biol Cell 2014; 25:3147-65. [PMID: 25143400 PMCID: PMC4196866 DOI: 10.1091/mbc.e14-05-0951] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Actin-based protrusions are important for signaling and migration during development and homeostasis. Gain- and loss-of-function and quantitative approaches are used to define differential roles for the actin elongation factors Diaphanous and Enabled in regulating distinct protrusive behaviors in different tissues during Drosophila morphogenesis. Actin-based protrusions are important for signaling and migration during development and homeostasis. Defining how different tissues in vivo craft diverse protrusive behaviors using the same genomic toolkit of actin regulators is a current challenge. The actin elongation factors Diaphanous and Enabled both promote barbed-end actin polymerization and can stimulate filopodia in cultured cells. However, redundancy in mammals and Diaphanous’ role in cytokinesis limited analysis of whether and how they regulate protrusions during development. We used two tissues driving Drosophila dorsal closure—migratory leading-edge (LE) and nonmigratory amnioserosal (AS) cells—as models to define how cells shape distinct protrusions during morphogenesis. We found that nonmigratory AS cells produce filopodia that are morphologically and dynamically distinct from those of LE cells. We hypothesized that differing Enabled and/or Diaphanous activity drives these differences. Combining gain- and loss-of-function with quantitative approaches revealed that Diaphanous and Enabled each regulate filopodial behavior in vivo and defined a quantitative “fingerprint”—the protrusive profile—which our data suggest is characteristic of each actin regulator. Our data suggest that LE protrusiveness is primarily Enabled driven, whereas Diaphanous plays the primary role in the AS, and reveal each has roles in dorsal closure, but its robustness ensures timely completion in their absence.
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Affiliation(s)
- Stephanie H Nowotarski
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Natalie McKeon
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Rachel J Moser
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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Engel U, Zhan Y, Long JB, Boyle SN, Ballif BA, Dorey K, Gygi SP, Koleske AJ, Vanvactor D. Abelson phosphorylation of CLASP2 modulates its association with microtubules and actin. Cytoskeleton (Hoboken) 2014; 71:195-209. [PMID: 24520051 PMCID: PMC4054870 DOI: 10.1002/cm.21164] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 12/21/2013] [Accepted: 12/30/2013] [Indexed: 11/20/2022]
Abstract
The Abelson (Abl) non-receptor tyrosine kinase regulates the cytoskeleton during multiple stages of neural development, from neurulation, to the articulation of axons and dendrites, to synapse formation and maintenance. We previously showed that Abl is genetically linked to the microtubule (MT) plus end tracking protein (+TIP) CLASP in Drosophila. Here we show in vertebrate cells that Abl binds to CLASP and phosphorylates it in response to serum or PDGF stimulation. In vitro, Abl phosphorylates CLASP with a Km of 1.89 µM, indicating that CLASP is a bona fide substrate. Abl-phosphorylated tyrosine residues that we detect in CLASP by mass spectrometry lie within previously mapped F-actin and MT plus end interaction domains. Using purified proteins, we find that Abl phosphorylation modulates direct binding between purified CLASP2 with both MTs and actin. Consistent with these observations, Abl-induced phosphorylation of CLASP2 modulates its localization as well as the distribution of F-actin structures in spinal cord growth cones. Our data suggest that the functional relationship between Abl and CLASP2 is conserved and provides a means to control the CLASP2 association with the cytoskeleton. © 2014 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Ulrike Engel
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts; Nikon Imaging Center, the University of Heidelberg, Bioquant, 69120, Heidelberg, Germany
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Ena/VASP Enabled is a highly processive actin polymerase tailored to self-assemble parallel-bundled F-actin networks with Fascin. Proc Natl Acad Sci U S A 2014; 111:4121-6. [PMID: 24591594 DOI: 10.1073/pnas.1322093111] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Filopodia are exploratory finger-like projections composed of multiple long, straight, parallel-bundled actin filaments that protrude from the leading edge of migrating cells. Drosophila melanogaster Enabled (Ena) is a member of the Ena/vasodilator-stimulated phosphoprotein protein family, which facilitates the assembly of filopodial actin filaments that are bundled by Fascin. However, the mechanism by which Ena and Fascin promote the assembly of uniformly thick F-actin bundles that are capable of producing coordinated protrusive forces without buckling is not well understood. We used multicolor evanescent wave fluorescence microscopy imaging to follow individual Ena molecules on both single and Fascin-bundled F-actin in vitro. Individual Ena tetramers increase the elongation rate approximately two- to threefold and inhibit capping protein by remaining processively associated with the barbed end for an average of ∼10 s in solution, for ∼60 s when immobilized on a surface, and for ∼110 s when multiple Ena tetramers are clustered on a surface. Ena also can gather and simultaneously elongate multiple barbed ends. Collectively, these properties could facilitate the recruitment of Fascin and initiate filopodia formation. Remarkably, we found that Ena's actin-assembly properties are tunable on Fascin-bundled filaments, facilitating the formation of filopodia-like F-actin networks without tapered barbed ends. Ena-associated trailing barbed ends in Fascin-bundled actin filaments have approximately twofold more frequent and approximately fivefold longer processive runs, allowing them to catch up with leading barbed ends efficiently. Therefore, Fascin and Ena cooperate to extend and maintain robust filopodia of uniform thickness with aligned barbed ends by a unique mechanistic cycle.
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31
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Spracklen AJ, Kelpsch DJ, Chen X, Spracklen CN, Tootle TL. Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis. Mol Biol Cell 2013; 25:397-411. [PMID: 24284900 PMCID: PMC3907279 DOI: 10.1091/mbc.e13-07-0366] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Tight regulation of actin remodeling is essential for development, and misregulation results in disease. Cytoskeletal dynamics are regulated by prostaglandins (PGs)—lipid signals. PGs temporally regulate actin remodeling during Drosophila oogenesis, at least in part, by modulating the activity of the actin elongation factor Enabled. Prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton—temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin remodeling, including actin filaments and aggregates, within the posterior nurse cells of S9 follicles; wild-type follicles exhibit similar structures at a low frequency. Hu li tai shao (Hts-RC) and Villin (Quail), an actin bundler, localize to all early actin structures, whereas Enabled (Ena), an actin elongation factor, preferentially localizes to those in pxt mutants. Reduced Ena levels strongly suppress early actin remodeling in pxt mutants. Furthermore, loss of Pxt results in reduced Ena localization to the sites of bundle formation during S10B. Together these data lead to a model in which PGs temporally regulate actin remodeling during Drosophila oogenesis by controlling Ena localization/activity, such that in S9, PG signaling inhibits, whereas at S10B, it promotes Ena-dependent actin remodeling.
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Affiliation(s)
- Andrew J Spracklen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242 Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242
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32
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CDC42 switches IRSp53 from inhibition of actin growth to elongation by clustering of VASP. EMBO J 2013; 32:2735-50. [PMID: 24076653 DOI: 10.1038/emboj.2013.208] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 08/30/2013] [Indexed: 12/21/2022] Open
Abstract
Filopodia explore the environment, sensing soluble and mechanical cues during directional motility and tissue morphogenesis. How filopodia are initiated and spatially restricted to specific sites on the plasma membrane is still unclear. Here, we show that the membrane deforming and curvature sensing IRSp53 (Insulin Receptor Substrate of 53 kDa) protein slows down actin filament barbed end growth. This inhibition is relieved by CDC42 and counteracted by VASP, which also binds to IRSp53. The VASP:IRSp53 interaction is regulated by activated CDC42 and promotes high-density clustering of VASP, which is required for processive actin filament elongation. The interaction also mediates VASP recruitment to liposomes. In cells, IRSp53 and VASP accumulate at discrete foci at the leading edge, where filopodia are initiated. Genetic removal of IRSp53 impairs the formation of VASP foci, filopodia and chemotactic motility, while IRSp53 null mice display defective wound healing. Thus, IRSp53 dampens barbed end growth. CDC42 activation inhibits this activity and promotes IRSp53-dependent recruitment and clustering of VASP to drive actin assembly. These events result in spatial restriction of VASP filament elongation for initiation of filopodia during cell migration, invasion, and tissue repair.
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Sano H, Kunwar PS, Renault AD, Barbosa V, Clark IBN, Ishihara S, Sugimura K, Lehmann R. The Drosophila actin regulator ENABLED regulates cell shape and orientation during gonad morphogenesis. PLoS One 2012; 7:e52649. [PMID: 23300733 PMCID: PMC3530444 DOI: 10.1371/journal.pone.0052649] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 11/16/2012] [Indexed: 12/27/2022] Open
Abstract
Organs develop distinctive morphologies to fulfill their unique functions. We used Drosophila embryonic gonads as a model to study how two different cell lineages, primordial germ cells (PGCs) and somatic gonadal precursors (SGPs), combine to form one organ. We developed a membrane GFP marker to image SGP behaviors live. These studies show that a combination of SGP cell shape changes and inward movement of anterior and posterior SGPs leads to the compaction of the spherical gonad. This process is disrupted in mutants of the actin regulator, enabled (ena). We show that Ena coordinates these cell shape changes and the inward movement of the SGPs, and Ena affects the intracellular localization of DE-cadherin (DE-cad). Mathematical simulation based on these observations suggests that changes in DE-cad localization can generate the forces needed to compact an elongated structure into a sphere. We propose that Ena regulates force balance in the SGPs by sequestering DE-cad, leading to the morphogenetic movement required for gonad compaction.
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Affiliation(s)
- Hiroko Sano
- HHMI and Developmental Genetics Program, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University Medical Center, New York, New York, United States of America.
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Slováková J, Speicher S, Sánchez-Soriano N, Prokop A, Carmena A. The actin-binding protein Canoe/AF-6 forms a complex with Robo and is required for Slit-Robo signaling during axon pathfinding at the CNS midline. J Neurosci 2012; 32:10035-44. [PMID: 22815517 PMCID: PMC6621277 DOI: 10.1523/jneurosci.6342-11.2012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 05/07/2012] [Accepted: 05/29/2012] [Indexed: 11/21/2022] Open
Abstract
Axon guidance is a key process during nervous system development and regeneration. One of the best established paradigms to study the mechanisms underlying this process is the axon decision of whether or not to cross the midline in the Drosophila CNS. An essential regulator of that decision is the well conserved Slit-Robo signaling pathway. Slit guidance cues act through Robo receptors to repel axons from the midline. Despite good progress in our knowledge about these proteins, the intracellular mechanisms associated with Robo function remain poorly defined. In this work, we found that the scaffolding protein Canoe (Cno), the Drosophila orthologue of AF-6/Afadin, is essential for Slit-Robo signaling. Cno is expressed along longitudinal axonal pioneer tracts, and longitudinal Robo/Fasciclin2-positive axons aberrantly cross the midline in cno mutant embryos. cno mutant primary neurons show a significant reduction of Robo localized in growth cone filopodia and Cno forms a complex with Robo in vivo. Moreover, the commissureless (comm) phenotype (i.e., lack of commissures due to constitutive surface presentation of Robo in all neurons) is suppressed in comm, cno double-mutant embryos. Specific genetic interactions between cno, slit, robo, and genes encoding other components of the Robo pathway, such as Neurexin-IV, Syndecan, and Rac GTPases, further confirm that Cno functionally interacts with the Slit-Robo pathway. Our data argue that Cno is a novel regulator of the Slit-Robo signaling pathway, crucial for regulating the subcellular localization of Robo and for transducing its signaling to the actin cytoskeleton during axon guidance at the midline.
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Affiliation(s)
- Jana Slováková
- Instituto de Neurociencias, CSIC/UMH, 03550 Sant Joan d'Alacant, Spain, and
| | - Stephan Speicher
- Instituto de Neurociencias, CSIC/UMH, 03550 Sant Joan d'Alacant, Spain, and
| | - Natalia Sánchez-Soriano
- Faculty of Life Sciences, Wellcome Trust Centre for Cell-Matrix Research, Manchester M13 9PT, United Kingdom
| | - Andreas Prokop
- Faculty of Life Sciences, Wellcome Trust Centre for Cell-Matrix Research, Manchester M13 9PT, United Kingdom
| | - Ana Carmena
- Instituto de Neurociencias, CSIC/UMH, 03550 Sant Joan d'Alacant, Spain, and
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Weber AL, Khan GF, Magwire MM, Tabor CL, Mackay TFC, Anholt RRH. Genome-wide association analysis of oxidative stress resistance in Drosophila melanogaster. PLoS One 2012; 7:e34745. [PMID: 22496853 PMCID: PMC3319608 DOI: 10.1371/journal.pone.0034745] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 03/08/2012] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Aerobic organisms are susceptible to damage by reactive oxygen species. Oxidative stress resistance is a quantitative trait with population variation attributable to the interplay between genetic and environmental factors. Drosophila melanogaster provides an ideal system to study the genetics of variation for resistance to oxidative stress. METHODS AND FINDINGS We used 167 wild-derived inbred lines of the Drosophila Genetic Reference Panel for a genome-wide association study of acute oxidative stress resistance to two oxidizing agents, paraquat and menadione sodium bisulfite. We found significant genetic variation for both stressors. Single nucleotide polymorphisms (SNPs) associated with variation in oxidative stress resistance were often sex-specific and agent-dependent, with a small subset common for both sexes or treatments. Associated SNPs had moderately large effects, with an inverse relationship between effect size and allele frequency. Linear models with up to 12 SNPs explained 67-79% and 56-66% of the phenotypic variance for resistance to paraquat and menadione sodium bisulfite, respectively. Many genes implicated were novel with no known role in oxidative stress resistance. Bioinformatics analyses revealed a cellular network comprising DNA metabolism and neuronal development, consistent with targets of oxidative stress-inducing agents. We confirmed associations of seven candidate genes associated with natural variation in oxidative stress resistance through mutational analysis. CONCLUSIONS We identified novel candidate genes associated with variation in resistance to oxidative stress that have context-dependent effects. These results form the basis for future translational studies to identify oxidative stress susceptibility/resistance genes that are evolutionary conserved and might play a role in human disease.
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Affiliation(s)
- Allison L Weber
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America.
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36
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Abl-1-bridged tyrosine phosphorylation of VASP by Abelson kinase impairs association of VASP to focal adhesions and regulates leukaemic cell adhesion. Biochem J 2012; 441:889-99. [PMID: 22014333 DOI: 10.1042/bj20110951] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mena [mammalian Ena (Enabled)]/VASP (vasodilator-stimulated phosphoprotein) proteins are the homologues of Drosophila Ena. In Drosophila, Ena is a substrate of the tyrosine kinase DAbl (Drosophila Abl). However, the link between Abl and the Mena/VASP family is not fully understood in mammals. We previously reported that Abi-1 (Abl interactor 1) promotes phosphorylation of Mena and BCAP (B-cell adaptor for phosphoinositide 3-kinase) by bridging the interaction between c-Abl and the substrate. In the present study we have identified VASP, another member of the Mena/VASP family, as an Abi-1-bridged substrate of Abl. VASP is phosphorylated by Abl when Abi-1 is co-expressed. We also found that VASP interacted with Abi-1 both in vitro and in vivo. VASP was tyrosine-phosphorylated in Bcr-Abl-positive leukaemic cells in an Abi-1-dependent manner. Co-expression of c-Abl and Abi-1 or the phosphomimetic Y39D mutation in VASP resulted in less accumulation of VASP at focal adhesions. VASP Y39D had a reduced affinity to the proline-rich region of zyxin. Interestingly, overexpression of both phosphomimetic and unphosphorylated forms of VASP, but not wild-type VASP, impaired adhesion of K562 cells to fibronectin. These results suggest that the phosphorylation and dephosphorylation cycle of VASP by the Abi-1-bridged mechanism regulates association of VASP with focal adhesions, which may regulate adhesion of Bcr-Abl-transformed leukaemic cells.
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Xiong W, Rebay I. Abelson tyrosine kinase is required for Drosophila photoreceptor morphogenesis and retinal epithelial patterning. Dev Dyn 2011; 240:1745-55. [PMID: 21674685 DOI: 10.1002/dvdy.22674] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Coordinated differentiation and morphogenesis transform the Drosophila retina from a layer of epithelial cells into a complex three-dimensional organ. In this study we show that the Abelson (Abl) tyrosine kinase localizes to the dynamically remodeling apical-junctional membrane domains of the developing photoreceptor cells. Analyses of abl mutant clone phenotypes demonstrate that abl is required for enriched localization of adherens junction and apical polarity complex proteins at photoreceptor-photoreceptor cell junctions and apical membrane domains, respectively, for rhabdomere generation and for spatial organization of ommatidial cells along the apical-basal axis of the epithelium. Loss of abl does not alter expression or localization of Enabled (Ena) nor does heterozygosity for ena dominantly suppress the abl phenotypes, suggesting the downstream effector mechanisms used by Abl in the eye may differ from those used in the embryo. Together our results reveal a prominent role for Abl in coordinating multiple aspects of photoreceptor morphogenesis.
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Affiliation(s)
- Wenjun Xiong
- Ben May Department for Cancer Research, The University of Chicago, Chicago, Illinois, USA
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38
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Profirovic J, Han J, Andreeva AV, Neamu RF, Pavlovic S, Vogel SM, Walter U, Voyno-Yasenetskaya TA. Vasodilator-stimulated phosphoprotein deficiency potentiates PAR-1-induced increase in endothelial permeability in mouse lungs. J Cell Physiol 2011; 226:1255-64. [PMID: 20945373 DOI: 10.1002/jcp.22453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Vasodilator-stimulated phosphoprotein (VASP) is implicated in the protection of the endothelial barrier in vitro and in vivo. The function of VASP in thrombin signaling in the endothelial cells (ECs) is not known. For the first time we studied the effects of VASP deficiency on EC permeability and pulmonary vascular permeability in response to thrombin receptor stimulation. We provided the evidence that VASP deficiency potentiates the increase in endothelial permeability induced by activation of thrombin receptor in cultured human umbilical vein endothelial cells (HUVECs) and isolated mouse lungs. Using transendothelial resistance measurement, we showed that siRNA-mediated VASP downregulation in HUVECs leads to a potentiation of thrombin- and protease-activated receptor 1 (PAR-1) agonist-induced increase in endothelial permeability. Compared to control cells, VASP-deficient HUVECs had delayed endothelial junctional reassembly and abrogated VE-cadherin cytoskeletal anchoring in the recovery phase after thrombin stimulation, as demonstrated by immunofluorescence studies and cell fractionation analysis, respectively. Measurement of the capillary filtration coefficient in isolated mouse lungs demonstrated that VASP(-/-) mice have increased microvascular permeability in response to infusion with PAR-1 agonist compared to wild type mice. Lack of VASP led to decreased Rac1 activation both in VASP-deficient HUVECs after thrombin stimulation and VASP(-/-) mouse lungs after PAR-1 agonist infusion, indicating that VASP effects on thrombin signaling may be correlated with changes in Rac1 activity. This study demonstrates that VASP may play critical and complex role in the regulation of thrombin-dependent disruption of the endothelial barrier function.
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Affiliation(s)
- Jasmina Profirovic
- Department of Pharmacology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA.
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Gonçalves-Pimentel C, Gombos R, Mihály J, Sánchez-Soriano N, Prokop A. Dissecting regulatory networks of filopodia formation in a Drosophila growth cone model. PLoS One 2011; 6:e18340. [PMID: 21464901 PMCID: PMC3065487 DOI: 10.1371/journal.pone.0018340] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 02/25/2011] [Indexed: 11/18/2022] Open
Abstract
F-actin networks are important structural determinants of cell shape and morphogenesis. They are regulated through a number of actin-binding proteins. The function of many of these proteins is well understood, but very little is known about how they cooperate and integrate their activities in cellular contexts. Here, we have focussed on the cellular roles of actin regulators in controlling filopodial dynamics. Filopodia are needle-shaped, actin-driven cell protrusions with characteristic features that are well conserved amongst vertebrates and invertebrates. However, existing models of filopodia formation are still incomplete and controversial, pieced together from a wide range of different organisms and cell types. Therefore, we used embryonic Drosophila primary neurons as one consistent cellular model to study filopodia regulation. Our data for loss-of-function of capping proteins, enabled, different Arp2/3 complex components, the formin DAAM and profilin reveal characteristic changes in filopodia number and length, providing a promising starting point to study their functional relationships in the cellular context. Furthermore, the results are consistent with effects reported for the respective vertebrate homologues, demonstrating the conserved nature of our Drosophila model system. Using combinatorial genetics, we demonstrate that different classes of nucleators cooperate in filopodia formation. In the absence of Arp2/3 or DAAM filopodia numbers are reduced, in their combined absence filopodia are eliminated, and in genetic assays they display strong functional interactions with regard to filopodia formation. The two nucleators also genetically interact with enabled, but not with profilin. In contrast, enabled shows strong genetic interaction with profilin, although loss of profilin alone does not affect filopodia numbers. Our genetic data support a model in which Arp2/3 and DAAM cooperate in a common mechanism of filopodia formation that essentially depends on enabled, and is regulated through profilin activity at different steps.
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Affiliation(s)
- Catarina Gonçalves-Pimentel
- Wellcome Trust Centre for Cell-Matrix
Research, Faculty of Life Sciences, Manchester, United Kingdom
- Center for Neuroscience and Cell Biology,
University of Coimbra, Coimbra, Portugal
| | - Rita Gombos
- Biological Research Center, Hungarian Academy
of Sciences, Institute of Genetics, Szeged, Hungary
| | - József Mihály
- Biological Research Center, Hungarian Academy
of Sciences, Institute of Genetics, Szeged, Hungary
| | - Natalia Sánchez-Soriano
- Wellcome Trust Centre for Cell-Matrix
Research, Faculty of Life Sciences, Manchester, United Kingdom
| | - Andreas Prokop
- Wellcome Trust Centre for Cell-Matrix
Research, Faculty of Life Sciences, Manchester, United Kingdom
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40
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Dent EW, Gupton SL, Gertler FB. The growth cone cytoskeleton in axon outgrowth and guidance. Cold Spring Harb Perspect Biol 2011; 3:cshperspect.a001800. [PMID: 21106647 DOI: 10.1101/cshperspect.a001800] [Citation(s) in RCA: 394] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Axon outgrowth and guidance to the proper target requires the coordination of filamentous (F)-actin and microtubules (MTs), the dynamic cytoskeletal polymers that promote shape change and locomotion. Over the past two decades, our knowledge of the many guidance cues, receptors, and downstream signaling cascades involved in neuronal outgrowth and guidance has increased dramatically. Less is known, however, about how those cascades of information converge and direct appropriate remodeling and interaction of cytoskeletal polymers, the ultimate effectors of movement and guidance. During development, much of the communication that occurs between environmental guidance cues and the cytoskeleton takes place at the growing tip of the axon, the neuronal growth cone. Several articles on this topic focus on the "input" to the growth cone, the myriad of receptor types, and their corresponding cognate ligands. Others investigate the signaling cascades initiated by receptors and propagated by second messenger pathways (i.e., kinases, phosphatases, GTPases). Ultimately, this plethora of information converges on proteins that associate directly with the actin and microtubule cytoskeletons. The role of these cytoskeletal-associated proteins, as well as the cytoskeleton itself in axon outgrowth and guidance, is the subject of this article.
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Affiliation(s)
- Erik W Dent
- Department of Anatomy, University of Wisconsin-Madison, 53706, USA
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41
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Teichmann HM, Shen K. UNC-6 and UNC-40 promote dendritic growth through PAR-4 in Caenorhabditis elegans neurons. Nat Neurosci 2010; 14:165-72. [PMID: 21186357 DOI: 10.1038/nn.2717] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 11/09/2010] [Indexed: 12/11/2022]
Abstract
Axons navigating through the developing nervous system are instructed by external attractive and repulsive cues. Emerging evidence suggests the same cues control dendrite development, but it is not understood how they differentially instruct axons and dendrites. We studied a C. elegans motor neuron whose axon and dendrite adopt different trajectories and lengths. We found that the guidance cue UNC-6 (Netrin) is required for both axon and dendrite development. Its repulsive receptor UNC-5 repelled the axon from the ventral cell body, whereas the attractive receptor UNC-40 (DCC) was dendritically enriched and promotes antero-posterior dendritic growth. Although the endogenous ventrally secreted UNC-6 instructs axon guidance, dorsal or even membrane-tethered UNC-6 could support dendrite development. Unexpectedly, the serine-threonine kinase PAR-4 (LKB1) was selectively required for the activity of the UNC-40 pathway in dendrite outgrowth. These data suggest that axon and dendrite of one neuron interpret common environmental cues with different receptors and downstream signaling pathways.
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Affiliation(s)
- Hannah M Teichmann
- Howard Hughes Medical Institute, Department of Biology, Stanford University, California, USA
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42
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Song JK, Kannan R, Merdes G, Singh J, Mlodzik M, Giniger E. Disabled is a bona fide component of the Abl signaling network. Development 2010; 137:3719-27. [PMID: 20940230 DOI: 10.1242/dev.050948] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abl is an essential regulator of cell migration and morphogenesis in both vertebrates and invertebrates. It has long been speculated that the adaptor protein Disabled (Dab), which is a key regulator of neuronal migration in the vertebrate brain, might be a component of this signaling pathway, but this idea has been controversial. We now demonstrate that null mutations of Drosophila Dab result in phenotypes that mimic Abl mutant phenotypes, both in axon guidance and epithelial morphogenesis. The Dab mutant interacts genetically with mutations in Abl, and with mutations in the Abl accessory factors trio and enabled (ena). Genetic epistasis tests show that Dab functions upstream of Abl and ena, and, consistent with this, we show that Dab is required for the subcellular localization of these two proteins. We therefore infer that Dab is a bona fide component of the core Abl signaling pathway in Drosophila.
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Affiliation(s)
- Jeong K Song
- Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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43
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Tucker PK, Evans IR, Wood W. Ena drives invasive macrophage migration in Drosophila embryos. Dis Model Mech 2010; 4:126-34. [PMID: 21045209 PMCID: PMC3008967 DOI: 10.1242/dmm.005694] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is seldom the primary tumour that proves fatal in cancer, with metastasis the fundamental pathological process for disease progression. Upregulation of Mena, a member of the evolutionarily conserved Ena/VASP family of actin cytoskeletal regulators, promotes metastasis and invasive motility of breast cancer cells in vivo. To complement in vitro studies of Ena/VASP function in fibroblasts, we manipulated levels of Ena, the Drosophila homologue of Mena, in migrating embryonic macrophages (haemocytes). Consistent with data from fibroblasts in vitro, Ena localises to regions of actin dynamics within migrating haemocytes, stimulates lamellipodial dynamics and positively regulates the number and length of filopodia. However, whereas Ena overexpression in fibroblasts reduces migration speeds, overexpressing Ena in haemocytes leads to a dramatic increase in migration speeds, more closely resembling the increased motility of breast cancer cells that overexpress Mena. We provide evidence that this key difference is due to spatial constraints imposed on cells within the three-dimensional environment of the embryo; this might explain how Mena can be used to promote aggressive migratory behaviour during cancer progression.
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Affiliation(s)
- Philippa K Tucker
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
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Abstract
ABL-family proteins comprise one of the best conserved branches of the tyrosine kinases. Each ABL protein contains an SH3-SH2-TK (Src homology 3-Src homology 2-tyrosine kinase) domain cassette, which confers autoregulated kinase activity and is common among nonreceptor tyrosine kinases. This cassette is coupled to an actin-binding and -bundling domain, which makes ABL proteins capable of connecting phosphoregulation with actin-filament reorganization. Two vertebrate paralogs, ABL1 and ABL2, have evolved to perform specialized functions. ABL1 includes nuclear localization signals and a DNA binding domain through which it mediates DNA damage-repair functions, whereas ABL2 has additional binding capacity for actin and for microtubules to enhance its cytoskeletal remodeling functions. Several types of posttranslational modifications control ABL catalytic activity, subcellular localization, and stability, with consequences for both cytoplasmic and nuclear ABL functions. Binding partners provide additional regulation of ABL catalytic activity, substrate specificity, and downstream signaling. Information on ABL regulatory mechanisms is being mined to provide new therapeutic strategies against hematopoietic malignancies caused by BCR-ABL1 and related leukemogenic proteins.
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Affiliation(s)
- John Colicelli
- Department of Biological Chemistry, Molecular Biology Institute and Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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Lin WH, Nebhan CA, Anderson BR, Webb DJ. Vasodilator-stimulated phosphoprotein (VASP) induces actin assembly in dendritic spines to promote their development and potentiate synaptic strength. J Biol Chem 2010; 285:36010-20. [PMID: 20826790 DOI: 10.1074/jbc.m110.129841] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dendritic spines are small actin-rich structures that receive the majority of excitatory synaptic input in the brain. The actin-based dynamics of spines are thought to mediate synaptic plasticity, which underlies cognitive processes, such as learning and memory. However, little is known about the molecular mechanisms that regulate actin dynamics in spines and synapses. In this study we show the multifunctional actin-binding protein vasodilator-stimulated phosphoprotein (VASP) regulates the density, size, and morphology of dendritic spines by inducing actin assembly in these structures. Knockdown of endogenous VASP by siRNA led to a significant decrease in the density of spines and synapses, whereas expression of siRNA-resistant VASP rescued this defect. The ability of VASP to modulate spine and synapse formation, maturation, and spine head enlargement is dependent on its actin binding Ena/VASP homology 2 (EVH2) domain and its EVH1 domain, which contributes to VASP localization to actin-rich structures. Moreover, VASP increases the amount of PSD-scaffolding proteins and the number of surface GluR1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) in spines. VASP knockdown results in a reduction in surface AMPAR density, suggesting a role for this protein in regulating synaptic strength. Consistent with this, VASP significantly enhances the retention of GluR1 in spines as determined by fluorescence recovery after photobleaching and increases AMPAR-mediated synaptic transmission. Collectively, our results suggest that actin polymerization and bundling by VASP are critical for spine formation, expansion, and modulating synaptic strength.
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Affiliation(s)
- Wan-Hsin Lin
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee 37235, USA
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Fleming T, Chien SC, Vanderzalm PJ, Dell M, Gavin MK, Forrester WC, Garriga G. The role of C. elegans Ena/VASP homolog UNC-34 in neuronal polarity and motility. Dev Biol 2010; 344:94-106. [PMID: 20452341 DOI: 10.1016/j.ydbio.2010.04.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 04/13/2010] [Accepted: 04/22/2010] [Indexed: 12/30/2022]
Abstract
Ena/VASP proteins mediate the effects of guidance cues on the actin cytoskeleton. The single C. elegans homolog of the Ena/VASP family of proteins, UNC-34, is required for the migrations of cells and growth cones. Here we show that unc-34 mutant alleles also interact genetically with Wnt mutants to reveal a role for unc-34 in the establishment of neuronal polarity along the C. elegans anterior-posterior axis. Our mutant analysis shows that eliminating UNC-34 function results in neuronal migration and polarity phenotypes that are enhanced at higher temperatures, revealing a heat-sensitive process that is normally masked by the presence of UNC-34. Finally, we show that the UNC-34 protein is expressed broadly and accumulates in axons and at the apical junctions of epithelial cells. While most mutants lacked detectable UNC-34, three unc-34 mutants that contained missense mutations in the EVH1 domain produced full-length UNC-34 that failed to localize to apical junctions and axons, supporting the role for the EVH1 domain in localizing Ena/VASP family members.
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Affiliation(s)
- Tinya Fleming
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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47
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Michael M, Vehlow A, Navarro C, Krause M. c-Abl, Lamellipodin, and Ena/VASP proteins cooperate in dorsal ruffling of fibroblasts and axonal morphogenesis. Curr Biol 2010; 20:783-91. [PMID: 20417104 PMCID: PMC2946563 DOI: 10.1016/j.cub.2010.03.048] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 03/17/2010] [Accepted: 03/17/2010] [Indexed: 11/06/2022]
Abstract
Background Tight regulation of cell motility is essential for many physiological processes, such as formation of a functional nervous system and wound healing. Drosophila Abl negatively regulates the actin cytoskeleton effector protein Ena during neuronal development in flies, and it has been postulated that this may occur through an unknown intermediary. Lamellipodin (Lpd) regulates cell motility and recruits Ena/VASP proteins (Ena, Mena, VASP, EVL) to the leading edge of cells. However, the regulation of this recruitment has remained unsolved. Results Here we show that Lpd is a substrate of Abl kinases and binds to the Abl SH2 domain. Phosphorylation of Lpd positively regulates the interaction between Lpd and Ena/VASP proteins. Consistently, efficient recruitment of Mena and EVL to Lpd at the leading edge requires Abl kinases. Furthermore, transient Lpd phosphorylation by Abl kinases upon netrin-1 stimulation of primary cortical neurons positively correlates with an increase in Lpd-Mena coprecipitation. Lpd is also transiently phosphorylated by Abl kinases upon platelet-derived growth factor (PDGF) stimulation, regulates PDGF-induced dorsal ruffling of fibroblasts and axonal morphogenesis, and cooperates with c-Abl in an Ena/VASP-dependent manner. Conclusions Our findings suggest that Abl kinases positively regulate Lpd-Ena/VASP interaction, Ena/VASP recruitment to Lpd at the leading edge, and Lpd-Ena/VASP function in axonal morphogenesis and in PDGF-induced dorsal ruffling. Our data do not support the suggested negative regulatory role of Abl for Ena. Instead, we propose that Lpd is the hitherto unknown intermediary between Abl and Ena/VASP proteins.
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Affiliation(s)
- Magdalene Michael
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, London SE1 1UL, UK
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48
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Sánchez-Soriano N, Gonçalves-Pimentel C, Beaven R, Haessler U, Ofner-Ziegenfuss L, Ballestrem C, Prokop A. Drosophila growth cones: a genetically tractable platform for the analysis of axonal growth dynamics. Dev Neurobiol 2010; 70:58-71. [PMID: 19937774 DOI: 10.1002/dneu.20762] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The formation of neuronal networks, during development and regeneration, requires outgrowth of axons along reproducible paths toward their appropriate postsynaptic target cells. Axonal extension occurs at growth cones (GCs) at the tips of axons. GC advance and navigation requires the activity of their cytoskeletal networks, comprising filamentous actin (F-actin) in lamellipodia and filopodia as well as dynamic microtubules (MTs) emanating from bundles of the axonal core. The molecular mechanisms governing these two cytoskeletal networks, their cross-talk, and their response to extracellular signaling cues are only partially understood, hindering our conceptual understanding of how regulated changes in GC behavior are controlled. Here, we introduce Drosophila GCs as a suitable model to address these mechanisms. Morphological and cytoskeletal readouts of Drosophila GCs are similar to those of other models, including mammals, as demonstrated here for MT and F-actin dynamics, axonal growth rates, filopodial structure and motility, organizational principles of MT networks, and subcellular marker localization. Therefore, we expect fundamental insights gained in Drosophila to be translatable into vertebrate biology. The advantage of the Drosophila model over others is its enormous amenability to combinatorial genetics as a powerful strategy to address the complexity of regulatory networks governing axonal growth. Thus, using pharmacological and genetic manipulations, we demonstrate a role of the actin cytoskeleton in a specific form of MT organization (loop formation), known to regulate GC pausing behavior. We demonstrate these events to be mediated by the actin-MT linking factor Short stop, thus identifying an essential molecular player in this context.
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Affiliation(s)
- Natalia Sánchez-Soriano
- Faculty of Life Sciences, Wellcome Trust Centre for Cell-Matrix Research, Manchester M13 9PT, United Kingdom
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49
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Bradley WD, Koleske AJ. Regulation of cell migration and morphogenesis by Abl-family kinases: emerging mechanisms and physiological contexts. J Cell Sci 2009; 122:3441-54. [PMID: 19759284 DOI: 10.1242/jcs.039859] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Abl-family non-receptor tyrosine kinases are essential regulators of the cytoskeleton. They transduce diverse extracellular cues into cytoskeletal rearrangements that have dramatic effects on cell motility and morphogenesis. Recent biochemical and genetic studies have revealed several mechanisms that Abl-family kinases use to mediate these effects. Abl-family kinases stimulate actin polymerization through the activation of cortactin, hematopoietic lineage cell-specific protein (HS1), WASp- and WAVE-family proteins, and Rac1. They also attenuate cell contractility by inhibiting RhoA and altering adhesion dynamics. These pathways impinge on several physiological processes, including development and maintenance of the nervous and immune systems, and epithelial morphogenesis. Elucidating how Abl-family kinases are regulated, and where and when they coordinate cytoskeletal changes, is essential for garnering a better understanding of these complex processes.
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Affiliation(s)
- William D Bradley
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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50
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Simonova OB, Burdina NV. Morphogenetic movement of cells in embryogenesis of Drosophila melanogaster: Mechanism and genetic control. Russ J Dev Biol 2009. [DOI: 10.1134/s1062360409050038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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