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Du WW, Qadir J, Du KY, Chen Y, Wu N, Yang BB. Nuclear Actin Polymerization Regulates Cell Epithelial-Mesenchymal Transition. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300425. [PMID: 37566765 PMCID: PMC10558697 DOI: 10.1002/advs.202300425] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/28/2023] [Indexed: 08/13/2023]
Abstract
Current studies on actin function primarily rely on cytoplasmic actin due to the absence of cellular models specifically expressing nuclear actin. Here, cell models capable of expressing varying levels of nuclear F/G-actin are generated and a significant role of nuclear actin in the regulation of epithelial-mesenchymal transition (EMT) is uncovered. Through immunoprecipitation and mass spectrometry analyses, distinct binding partners for nuclear F-actin (β-catenin, SMAD2, and SMAD3) and nuclear G-actin (MYBBP1A, NKRF, and MYPOP) are investigated, which respectively modulate EMT-promoting and EMT-repressing transcriptional events. While nuclear F-actin promotes EMT with enhanced cell migration, survival, and elongated mesenchymal morphology, nuclear G-actin represses EMT and related cell activities. Mechanistically, nuclear F-actin enhances β-catenin, SMAD2, and SMAD3 expression and stability in the nuclei, while nuclear G-actin increases MYBBP1A, NKRF, and MYPOP expression and stability in the nuclei. The association between nuclear F/G-actin and N-cadherin/E-cadherin in the cell lines (in vitro), and increased nuclear actin polymerization in the wound healing cells (in vivo) affirm a significant role of nuclear actin in EMT regulation. With evidence of nuclear actin polymerization and EMT during development, and irregularities in disease states such as cancer and fibrosis, targeting nuclear actin dynamics to trigger dysregulated EMT warrants ongoing study.
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Affiliation(s)
- William W. Du
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
| | - Javeria Qadir
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
| | - Kevin Y. Du
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
| | - Yu Chen
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
| | - Nan Wu
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
| | - Burton B. Yang
- Sunnybrook Research Instituteand Department of Laboratory Medicine and PathobiologyUniversity of TorontoTorontoONM4N3M5Canada
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2
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Identification and characterization of profilin gene family in rice. ELECTRON J BIOTECHN 2021. [DOI: 10.1016/j.ejbt.2021.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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3
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Abstract
Dynamic remodeling of the actin cytoskeleton is an essential feature for virtually all actin-dependent cellular processes, including cell migration, cell cycle progression, chromatin remodeling and gene expression, and even the DNA damage response. An altered actin cytoskeleton is a structural hallmark associated with numerous pathologies ranging from cardiovascular diseases to immune disorders, neurological diseases and cancer. The actin cytoskeleton in cells is regulated through the orchestrated actions of a myriad of actin-binding proteins. In this Review, we provide a brief overview of the structure and functions of the actin-monomer-binding protein profilin-1 (Pfn1) and then discuss how dysregulated expression of Pfn1 contributes to diseases associated with the cardiovascular system.
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Affiliation(s)
| | - David Gau
- Bioengineering, University of Pittsburgh
| | - Partha Roy
- Bioengineering, University of Pittsburgh.,Pathology, University of Pittsburgh, 306 Center for Bioengineering, University of Pittsburgh, 300 Technology Drive, Pittsburgh, PA 15219, USA
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4
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Zhu C, Kim SJ, Mooradian A, Wang F, Li Z, Holohan S, Collins PL, Wang K, Guo Z, Hoog J, Ma CX, Oltz EM, Held JM, Shao J. Cancer-associated exportin-6 upregulation inhibits the transcriptionally repressive and anticancer effects of nuclear profilin-1. Cell Rep 2021; 34:108749. [PMID: 33596420 PMCID: PMC8006859 DOI: 10.1016/j.celrep.2021.108749] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 12/29/2020] [Accepted: 01/21/2021] [Indexed: 01/22/2023] Open
Abstract
Aberrant expression of nuclear transporters and deregulated subcellular localization of their cargo proteins are emerging as drivers and therapeutic targets of cancer. Here, we present evidence that the nuclear exporter exportin-6 and its cargo profilin-1 constitute a functionally important and frequently deregulated axis in cancer. Exportin-6 upregulation occurs in numerous cancer types and is associated with poor patient survival. Reducing exportin-6 level in breast cancer cells triggers antitumor effects by accumulating nuclear profilin-1. Mechanistically, nuclear profilin-1 interacts with eleven-nineteen-leukemia protein (ENL) within the super elongation complex (SEC) and inhibits the ability of the SEC to drive transcription of numerous pro-cancer genes including MYC. XPO6 and MYC are positively correlated across diverse cancer types including breast cancer. Therapeutically, exportin-6 loss sensitizes breast cancer cells to the bromodomain and extra-terminal (BET) inhibitor JQ1. Thus, exportin-6 upregulation is a previously unrecognized cancer driver event by spatially inhibiting nuclear profilin-1 as a tumor suppressor.
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Affiliation(s)
- Cuige Zhu
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sun-Joong Kim
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Arshag Mooradian
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Faliang Wang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Surgical Oncology, The Children's Hospital, Zhejiang University School of Medicine, National Clinical Research Center for Child Health, Hangzhou 310052, China
| | - Ziqian Li
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial and Biochemical Pharmacy, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Sean Holohan
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Patrick L Collins
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Keren Wang
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Zhanfang Guo
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeremy Hoog
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Cynthia X Ma
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Eugene M Oltz
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| | - Jason M Held
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jieya Shao
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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5
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Pimm ML, Hotaling J, Henty-Ridilla JL. Profilin choreographs actin and microtubules in cells and cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2020; 355:155-204. [PMID: 32859370 PMCID: PMC7461721 DOI: 10.1016/bs.ircmb.2020.05.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Actin and microtubules play essential roles in aberrant cell processes that define and converge in cancer including: signaling, morphology, motility, and division. Actin and microtubules do not directly interact, however shared regulators coordinate these polymers. While many of the individual proteins important for regulating and choreographing actin and microtubule behaviors have been identified, the way these molecules collaborate or fail in normal or disease contexts is not fully understood. Decades of research focus on Profilin as a signaling molecule, lipid-binding protein, and canonical regulator of actin assembly. Recent reports demonstrate that Profilin also regulates microtubule dynamics and polymerization. Thus, Profilin can coordinate both actin and microtubule polymer systems. Here we reconsider the biochemical and cellular roles for Profilin with a focus on the essential cytoskeletal-based cell processes that go awry in cancer. We also explore how the use of model organisms has helped to elucidate mechanisms that underlie the regulatory essence of Profilin in vivo and in the context of disease.
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Affiliation(s)
- Morgan L Pimm
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States
| | - Jessica Hotaling
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States
| | - Jessica L Henty-Ridilla
- Department of Cell and Developmental Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States; Department of Biochemistry and Molecular Biology, State University of New York (SUNY) Upstate Medical University, Syracuse, NY, United States.
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6
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Abstract
Profilin is a ubiquitously expressed protein well known as a key regulator of actin polymerisation. The actin cytoskeleton is involved in almost all cellular processes including motility, endocytosis, metabolism, signal transduction and gene transcription. Hence, profilin's role in the cell goes beyond its direct and essential function in regulating actin dynamics. This review will focus on the interactions of Profilin 1 and its ligands at the plasma membrane, in the cytoplasm and the nucleus of the cells and the regulation of profilin activity within those cell compartments. We will discuss the interactions of profilin in cell signalling pathways and highlight the importance of the cell context in the multiple functions that this small essential protein has in conjunction with its role in cytoskeletal organisation and dynamics. We will review some of the mechanisms that control profilin expression and the implications of changed expression of profilin in the light of cancer biology and other pathologies.
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7
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Simonian M, Shirasaki D, Lee VS, Bervini D, Grace M, Loo RRO, Loo JA, Molloy MP, Stoodley MA. Proteomics identification of radiation-induced changes of membrane proteins in the rat model of arteriovenous malformation in pursuit of targets for brain AVM molecular therapy. Clin Proteomics 2018; 15:43. [PMID: 30602943 PMCID: PMC6305998 DOI: 10.1186/s12014-018-9217-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/12/2018] [Indexed: 12/27/2022] Open
Abstract
Background Rapid identification of novel targets and advancement of a vascular targeting strategy requires a comprehensive assessment of AVM endothelial membrane protein changes in response to irradiation. The aim of this study is to provide additional potential target protein molecules for evaluation in animal trials to promote intravascular thrombosis in AVM vessels post radiosurgery. Methods We employed in vivo biotinylation methodology that we developed, to label membrane proteins in the rat model of AVM post radiosurgery. Mass spectrometry expression (MSE) analysis was used to identify and quantify surface protein expression between irradiated and non irradiated rats, which mimics a radiosurgical treatment approach. Results Our proteomics data revealed differentially expressed membrane proteins between irradiated and non irradiated rats, e.g. profilin-1, ESM-1, ion channel proteins, annexin A2 and lumican. Conclusion This work provides additional potential target protein molecules for evaluation in animal trials to promote intravascular thrombosis in AVM vessels post radiosurgery. Electronic supplementary material The online version of this article (10.1186/s12014-018-9217-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margaret Simonian
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia.,2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Dyna Shirasaki
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Vivienne S Lee
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia
| | - David Bervini
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia.,3Neurosurgery Department, Bern University Hospital, Bern, Switzerland
| | - Michael Grace
- 4Genesis Cancer Care, Macquarie University Hospital, Sydney, NSW Australia
| | - Rachel R Ogorzalek Loo
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Joseph A Loo
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Mark P Molloy
- 5Department of Chemistry and Bimolecular Sciences, Australian Proteome Analysis Facility (APAF), Macquarie University, Sydney, NSW Australia.,Lawrence Penn Chair of Bowel Cancer Research, Faculty of Medicine and Health, Northern Clinical School, Sydney, Australia
| | - Marcus A Stoodley
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia
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8
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Coumans JVF, Davey RJ, Moens PDJ. Cofilin and profilin: partners in cancer aggressiveness. Biophys Rev 2018; 10:1323-1335. [PMID: 30027463 DOI: 10.1007/s12551-018-0445-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/08/2018] [Indexed: 02/07/2023] Open
Abstract
This review covers aspects of cofilin and profilin regulations and their influence on actin polymerisation responsible for cell motility and metastasis. The regulation of their activity by phosphorylation and nitration, miRs, PI(4,5)P2 binding, pH, oxidative stress and post-translational modification is described. In this review, we have highlighted selected similarities, complementarities and differences between the two proteins and how their interplay affects actin filament dynamics.
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Affiliation(s)
- Joelle V F Coumans
- School of Rural Medicine, University of New England, Armidale, Australia
| | - Rhonda J Davey
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia
| | - Pierre D J Moens
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia.
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9
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The Myb-related protein MYPOP is a novel intrinsic host restriction factor of oncogenic human papillomaviruses. Oncogene 2018; 37:6275-6284. [PMID: 30018400 PMCID: PMC6265261 DOI: 10.1038/s41388-018-0398-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 11/08/2022]
Abstract
The skin represents a physical and chemical barrier against invading pathogens, which is additionally supported by restriction factors that provide intrinsic cellular immunity. These factors detect viruses to block their replication cycle. Here, we uncover the Myb-related transcription factor, partner of profilin (MYPOP) as a novel antiviral protein. It is highly expressed in the epithelium and binds to the minor capsid protein L2 and the DNA of human papillomaviruses (HPV), which are the primary causative agents of cervical cancer and other tumors. The early promoter activity and early gene expression of the oncogenic HPV types 16 and 18 is potently silenced by MYPOP. Cellular MYPOP-depletion relieves the restriction of HPV16 infection, demonstrating that MYPOP acts as a restriction factor. Interestingly, we found that MYPOP protein levels are significantly reduced in diverse HPV-transformed cell lines and in HPV-induced cervical cancer. Decades ago it became clear that the early oncoproteins E6 and E7 cooperate to immortalize keratinocytes by promoting degradation of tumor suppressor proteins. Our findings suggest that E7 stimulates MYPOP degradation. Moreover, overexpression of MYPOP blocks colony formation of HPV and non-virally transformed keratinocytes, suggesting that MYPOP exhibits tumor suppressor properties.
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10
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Frantzi M, Klimou Z, Makridakis M, Zoidakis J, Latosinska A, Borràs DM, Janssen B, Giannopoulou I, Lygirou V, Lazaris AC, Anagnou NP, Mischak H, Roubelakis MG, Vlahou A. Silencing of Profilin-1 suppresses cell adhesion and tumor growth via predicted alterations in integrin and Ca2+ signaling in T24M-based bladder cancer models. Oncotarget 2018; 7:70750-70768. [PMID: 27683119 PMCID: PMC5342587 DOI: 10.18632/oncotarget.12218] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 09/13/2016] [Indexed: 12/14/2022] Open
Abstract
Bladder cancer (BC) is the second most common malignancy of the genitourinary system, characterized by the highest recurrence rate of all cancers. Treatment options are limited; thus a thorough understanding of the underlying molecular mechanisms is needed to guide the discovery of novel therapeutic targets. Profilins are actin binding proteins with attributed pleiotropic functions to cytoskeletal remodeling, cell adhesion, motility, even transcriptional regulation, not fully characterized yet. Earlier studies from our laboratory revealed that decreased tissue levels of Profilin-1 (PFN1) are correlated with BC progression to muscle invasive disease. Herein, we describe a comprehensive analysis of PFN1 silencing via shRNA, in vitro (by employing T24M cells) and in vivo [(with T24M xenografts in non-obese diabetic severe combined immunodeficient mice (NOD/SCID) mice]. A combination of phenotypic and molecular assays, including migration, proliferation, adhesion assays, flow cytometry and total mRNA sequencing, as well as immunohistochemistry for investigation of selected findings in human specimens were applied. A decrease in BC cell adhesion and tumor growth in vivo following PFN downregulation are observed, likely associated with the concomitant downregulation of Fibronectin receptor, Endothelin-1, and Actin polymerization. A decrease in the levels of multiple key members of the non-canonical Wnt/Ca2+ signaling pathway is also detected following PFN1 suppression, providing the groundwork for future studies, addressing the specific role of PFN1 in Ca2+ signaling, particularly in the muscle invasive disease.
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Affiliation(s)
- Maria Frantzi
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,Research and Development Department, Mosaiques Diagnostics GmbH, Hannover, Germany
| | - Zoi Klimou
- Laboratory of Biology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Cell and Gene Therapy Laboratory, Biomedical Research Foundation of The Academy of Athens, Athens, Greece
| | - Manousos Makridakis
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Jerome Zoidakis
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Agnieszka Latosinska
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Daniel M Borràs
- Research and Development Department, GenomeScan B.V., Leiden, The Netherlands
| | - Bart Janssen
- Research and Development Department, GenomeScan B.V., Leiden, The Netherlands
| | - Ioanna Giannopoulou
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Vasiliki Lygirou
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Andreas C Lazaris
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Nicholas P Anagnou
- Laboratory of Biology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Cell and Gene Therapy Laboratory, Biomedical Research Foundation of The Academy of Athens, Athens, Greece
| | - Harald Mischak
- Research and Development Department, Mosaiques Diagnostics GmbH, Hannover, Germany
| | - Maria G Roubelakis
- Laboratory of Biology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece.,Cell and Gene Therapy Laboratory, Biomedical Research Foundation of The Academy of Athens, Athens, Greece
| | - Antonia Vlahou
- Proteomics Laboratory, Biotechnology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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11
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Rennella E, Sekhar A, Kay LE. Self-Assembly of Human Profilin-1 Detected by Carr-Purcell-Meiboom-Gill Nuclear Magnetic Resonance (CPMG NMR) Spectroscopy. Biochemistry 2017; 56:692-703. [PMID: 28052669 DOI: 10.1021/acs.biochem.6b01263] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein oligomerization in the cell has important implications for both health and disease, and an understanding of the mechanisms by which proteins can self-associate is, therefore, of critical interest. Initial stages of the oligomerization process can be hard to detect, as they often involve the formation of sparsely populated and transient states that are difficult to characterize by standard biophysical approaches. Using relaxation dispersion nuclear magnetic resonance spectroscopy, we study the oligomerization of human profilin-1, a protein that regulates the polymerization of actin. We show that in solution and at millimolar concentrations profilin-1 is predominantly monomeric. However, fits of concentration-dependent relaxation data are consistent with the formation of a higher-order oligomer that is generated via a multistep process. Together with crystallographic data for profilin-2, a homologue of the protein studied here, our results suggest that profilin-1 forms a sparsely populated tetrameric conformer in solution.
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Affiliation(s)
- Enrico Rennella
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada
| | - Ashok Sekhar
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada.,Program in Molecular Structure and Function, Hospital for Sick Children , 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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12
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Kooij V, Viswanathan MC, Lee DI, Rainer PP, Schmidt W, Kronert WA, Harding SE, Kass DA, Bernstein SI, Van Eyk JE, Cammarato A. Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy. Cardiovasc Res 2016; 110:238-48. [PMID: 26956799 PMCID: PMC4836629 DOI: 10.1093/cvr/cvw050] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 02/28/2016] [Indexed: 11/17/2022] Open
Abstract
Aims Heart failure is often preceded by cardiac hypertrophy, which is characterized by increased cell size, altered protein abundance, and actin cytoskeletal reorganization. Profilin is a well-conserved, ubiquitously expressed, multifunctional actin-binding protein, and its role in cardiomyocytes is largely unknown. Given its involvement in vascular hypertrophy, we aimed to test the hypothesis that profilin-1 is a key mediator of cardiomyocyte-specific hypertrophic remodelling. Methods and results Profilin-1 was elevated in multiple mouse models of hypertrophy, and a cardiomyocyte-specific increase of profilin in Drosophila resulted in significantly larger heart tube dimensions. Moreover, adenovirus-mediated overexpression of profilin-1 in neonatal rat ventricular myocytes (NRVMs) induced a hypertrophic response, measured by increased myocyte size and gene expression. Profilin-1 silencing suppressed the response in NRVMs stimulated with phenylephrine or endothelin-1. Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade. Confocal microscopy showed that profilin localized to the Z-line of Drosophila myofibrils under normal conditions and accumulated near the M-line when overexpressed. Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function. Conclusion Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy. We show that overexpression of profilin is sufficient to induce cardiomyocyte hypertrophy and sarcomeric remodelling, and silencing of profilin attenuates the hypertrophic response.
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Affiliation(s)
- Viola Kooij
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Meera C Viswanathan
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Dong I Lee
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Peter P Rainer
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA Division of Cardiology, Medical University of Graz, Graz, Austria
| | - William Schmidt
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - William A Kronert
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Sian E Harding
- National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - David A Kass
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | | | - Jennifer E Van Eyk
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA Advanced Clinical Biosystems Research Institute, Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
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13
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Actin, actin-binding proteins, and actin-related proteins in the nucleus. Histochem Cell Biol 2016; 145:373-88. [PMID: 26847179 DOI: 10.1007/s00418-015-1400-9] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2015] [Indexed: 10/25/2022]
Abstract
Extensive research in the past decade has significantly broadened our view about the role actin plays in the life of the cell and added novel aspects to actin research. One of these new aspects is the discovery of the existence of nuclear actin which became evident only recently. Nuclear activities including transcriptional activation in the case of all three RNA polymerases, editing and nuclear export of mRNAs, and chromatin remodeling all depend on actin. It also became clear that there is a fine-tuned equilibrium between cytoplasmic and nuclear actin pools and that this balance is ensured by an export-import system dedicated to actin. After over half a century of research on conventional actin and its organizing partners in the cytoplasm, it was also an unexpected finding that the nucleus contains more than 30 actin-binding proteins and new classes of actin-related proteins which are not able to form filaments but had evolved nuclear-specific functions. The actin-binding and actin-related proteins in the nucleus have been linked to RNA transcription and processing, nuclear transport, and chromatin remodeling. In this paper, we attempt to provide an overview of the wide range of information that is now available about actin, actin-binding, and actin-related proteins in the nucleus.
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14
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Diamond MI, Cai S, Boudreau A, Carey CJ, Lyle N, Pappu RV, Swamidass SJ, Bissell M, Piwnica-Worms H, Shao J. Subcellular localization and Ser-137 phosphorylation regulate tumor-suppressive activity of profilin-1. J Biol Chem 2015; 290:9075-86. [PMID: 25681442 DOI: 10.1074/jbc.m114.619874] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Indexed: 12/18/2022] Open
Abstract
The actin-binding protein profilin-1 (Pfn1) inhibits tumor growth and yet is also required for cell proliferation and survival, an apparent paradox. We previously identified Ser-137 of Pfn1 as a phosphorylation site within the poly-l-proline (PLP) binding pocket. Here we confirm that Ser-137 phosphorylation disrupts Pfn1 binding to its PLP-containing ligands with little effect on actin binding. We find in mouse xenografts of breast cancer cells that mimicking Ser-137 phosphorylation abolishes cell cycle arrest and apoptotic sensitization by Pfn1 and confers a growth advantage to tumors. This indicates a previously unrecognized role of PLP binding in Pfn1 antitumor effects. Spatial restriction of Pfn1 to the nucleus or cytoplasm indicates that inhibition of tumor cell growth by Pfn1 requires its nuclear localization, and this activity is abolished by a phosphomimetic mutation on Ser-137. In contrast, cytoplasmic Pfn1 lacks inhibitory effects on tumor cell growth but rescues morphological and proliferative defects of PFN1 null mouse chondrocytes. These results help reconcile seemingly opposed cellular effects of Pfn1, provide new insights into the antitumor mechanism of Pfn1, and implicate Ser-137 phosphorylation as a potential therapeutic target for breast cancer.
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Affiliation(s)
- Marc I Diamond
- From the Center for Alzheimer's and Neurodegenerative Diseases, University of Texas, Southwestern Medical Center, Dallas, Texas 75390
| | - Shirong Cai
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77230
| | - Aaron Boudreau
- Department of Laboratory Medicine, Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California 94143
| | - Clifton J Carey
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Nicholas Lyle
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130
| | - Rohit V Pappu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130
| | - S Joshua Swamidass
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Mina Bissell
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and
| | - Helen Piwnica-Worms
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77230
| | - Jieya Shao
- Breast Oncology Program, Division of Oncology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
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15
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Rajakylä EK, Vartiainen MK. Rho, nuclear actin, and actin-binding proteins in the regulation of transcription and gene expression. Small GTPases 2014; 5:e27539. [PMID: 24603113 DOI: 10.4161/sgtp.27539] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Actin cytoskeleton is one of the main targets of Rho GTPases, which act as molecular switches on many signaling pathways. During the past decade, actin has emerged as an important regulator of gene expression. Nuclear actin plays a key role in transcription, chromatin remodeling, and pre-mRNA processing. In addition, the "status" of the actin cytoskeleton is used as a signaling intermediate by at least the MKL1-SRF and Hippo-pathways, which culminate in the transcriptional regulation of cytoskeletal and growth-promoting genes, respectively. Rho GTPases may therefore regulate gene expression by controlling either cytoplasmic or nuclear actin dynamics. Although the regulation of nuclear actin polymerization is still poorly understood, many actin-binding proteins, which are downstream effectors of Rho, are found in the nuclear compartment. In this review, we discuss the possible mechanisms and key proteins that may mediate the transcriptional regulation by Rho GTPases through actin.
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Affiliation(s)
- Eeva Kaisa Rajakylä
- Program in Cell and Molecular Biology; Institute of Biotechnology; University of Helsinki; Helsinki, Finland
| | - Maria K Vartiainen
- Program in Cell and Molecular Biology; Institute of Biotechnology; University of Helsinki; Helsinki, Finland
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16
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Pae M, Romeo GR. The multifaceted role of profilin-1 in adipose tissue inflammation and glucose homeostasis. Adipocyte 2014; 3:69-74. [PMID: 24575374 DOI: 10.4161/adip.26965] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 12/19/2022] Open
Abstract
Profilin-1 (pfn) is a small ubiquitous protein that can bind to: (1) G-actin, (2) phosphatidylinositol 4,5-bisphosphate, and (3) a heterogeneous group of proteins harboring poly-l-proline stretches. Through these interactions, pfn integrates signaling from a diverse array of extracellular cues with actin cytoskeleton dynamics. Cumulating evidence indicates that changes in pfn levels are associated and may play a pathogenic role in such inflammatory diseases as atherosclerosis and glomerulonephritis. We recently demonstrated that high fat diet (HFD) increases pfn expression in the white adipose tissue (WAT), but not in the liver or the muscle. Pfn heterozygote mice (PfnHet) were protected against HFD-induced glucose intolerance, and WAT and systemic inflammation, when compared to pfn wild-type mice. In addition to blunted accumulation of macrophages and reduced "pro-inflammatory" cytokines, the WAT of PfnHet exhibited preserved frequency of regulatory T cells. These findings suggest that pfn levels in WAT-both adipocytes and hematopoietic-derived cells-can modulate immune homeostasis within the WAT and glucose tolerance systemically. Here, we review the interaction of pfn with his diverse array of binding partners and discuss mechanisms that may underlie the effects of pfn dosage on insulin sensitivity and metabolic inflammation.
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17
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Profilin-1 downregulation has contrasting effects on early vs late steps of breast cancer metastasis. Oncogene 2013; 33:2065-74. [PMID: 23686314 DOI: 10.1038/onc.2013.166] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/19/2013] [Accepted: 04/10/2013] [Indexed: 12/23/2022]
Abstract
Profilin1 (Pfn1), a ubiquitously expressed actin-binding protein, has an indispensable role in migration and proliferation of normal cells. Seemingly contrary to its essential cellular functions, Pfn1's expression is downregulated in breast cancer, the significance of which is unclear. In this study, expression profiling of Pfn1 in human breast cancer specimens correlates lower Pfn1 expression levels with propensity to metastasize. Xenograft experiments further establish a causal relationship between loss of Pfn1 expression and increased dissemination of breast cancer cells (BCCs) from the primary mammary tumor. BCCs exhibit a hyperinvasive phenotype (marked by matrix metalloproteinase-9 upregulation, faster invasion through collagen matrix) and acquire increased proficiency to transmigrate through endothelial barrier (an obligatory step for vascular dissemination) when Pfn1 expression is suppressed. In Pfn1-deficient cells, hyperinvasiveness involves a phosphatidylinositol 3-kinase-PI(3,4)P2 signaling axis while augmented transendothelial migration occurs in a vascular endothelial growth factor-dependent manner. Contrasting these dissemination promoting activities, loss of Pfn1, however, dramatically inhibits metastatic outgrowth of disseminated BCCs, suggesting that Pfn1 has a key role in the metastatic colonization process. In summary, this study shows that Pfn1 has a dichotomous role in early vs late steps of breast cancer metastasis.
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18
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Ding Z, Bae YH, Roy P. Molecular insights on context-specific role of profilin-1 in cell migration. Cell Adh Migr 2012; 6:442-9. [PMID: 23076048 DOI: 10.4161/cam.21832] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Profilin-1 (Pfn1) is a ubiquitously expressed actin-monomer binding protein that has been linked to many cellular activities ranging from control of actin polymerization to gene transcription. Traditionally, Pfn1 has been considered to be an essential control element for actin polymerization and cell migration. Seemingly contrasting this view, a few recent studies have shown evidence of an inhibitory action of Pfn1 on motility of certain types of carcinoma cells. In this review, we summarize biochemistry and functional aspects of Pfn1 in normal cells and bring in newly emerged action of Pfn1 in cancer cells that may explain its context-specific role in cell migration.
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Affiliation(s)
- Zhijie Ding
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
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19
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Söderberg E, Hessle V, von Euler A, Visa N. Profilin is associated with transcriptionally active genes. Nucleus 2012; 3:290-9. [PMID: 22572953 PMCID: PMC3414406 DOI: 10.4161/nucl.20327] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We have raised antibodies against the profilin of Chironomus tentans to study the location of profilin relative to chromatin and to active genes in salivary gland polytene chromosomes. We show that a fraction of profilin is located in the nucleus, where profilin is highly concentrated in the nucleoplasm and at the nuclear periphery. Moreover, profilin is associated with multiple bands in the polytene chromosomes. By staining salivary glands with propidium iodide, we show that profilin does not co-localize with dense chromatin. Profilin associates instead with protein-coding genes that are transcriptionally active, as revealed by co-localization with hnRNP and snRNP proteins. We have performed experiments of transcription inhibition with actinomycin D and we show that the association of profilin with the chromosomes requires ongoing transcription. However, the interaction of profilin with the gene loci does not depend on RNA. Our results are compatible with profilin regulating actin polymerization in the cell nucleus. However, the association of actin with the polytene chromosomes of C. tentans is sensitive to RNase, whereas the association of profilin is not, and we propose therefore that the chromosomal location of profilin is independent of actin.
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Affiliation(s)
- Emilia Söderberg
- Department of Molecular Biology & Functional Genomics, Stockholm University, Stockholm, Sweden
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20
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Murk K, Wittenmayer N, Michaelsen-Preusse K, Dresbach T, Schoenenberger CA, Korte M, Jockusch BM, Rothkegel M. Neuronal profilin isoforms are addressed by different signalling pathways. PLoS One 2012; 7:e34167. [PMID: 22470532 PMCID: PMC3314592 DOI: 10.1371/journal.pone.0034167] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/23/2012] [Indexed: 01/29/2023] Open
Abstract
Profilins are prominent regulators of actin dynamics. While most mammalian cells express only one profilin, two isoforms, PFN1 and PFN2a are present in the CNS. To challenge the hypothesis that the expression of two profilin isoforms is linked to the complex shape of neurons and to the activity-dependent structural plasticity, we analysed how PFN1 and PFN2a respond to changes of neuronal activity. Simultaneous labelling of rodent embryonic neurons with isoform-specific monoclonal antibodies revealed both isoforms in the same synapse. Immunoelectron microscopy on brain sections demonstrated both profilins in synapses of the mature rodent cortex, hippocampus and cerebellum. Both isoforms were significantly more abundant in postsynaptic than in presynaptic structures. Immunofluorescence showed PFN2a associated with gephyrin clusters of the postsynaptic active zone in inhibitory synapses of embryonic neurons. When cultures were stimulated in order to change their activity level, active synapses that were identified by the uptake of synaptotagmin antibodies, displayed significantly higher amounts of both isoforms than non-stimulated controls. Specific inhibition of NMDA receptors by the antagonist APV in cultured rat hippocampal neurons resulted in a decrease of PFN2a but left PFN1 unaffected. Stimulation by the brain derived neurotrophic factor (BDNF), on the other hand, led to a significant increase in both synaptic PFN1 and PFN2a. Analogous results were obtained for neuronal nuclei: both isoforms were localized in the same nucleus, and their levels rose significantly in response to KCl stimulation, whereas BDNF caused here a higher increase in PFN1 than in PFN2a. Our results strongly support the notion of an isoform specific role for profilins as regulators of actin dynamics in different signalling pathways, in excitatory as well as in inhibitory synapses. Furthermore, they suggest a functional role for both profilins in neuronal nuclei.
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Affiliation(s)
- Kai Murk
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
| | - Nina Wittenmayer
- Department of Anatomy and Cell Biology, Center of Anatomy, Georg August University Göttingen, Göttingen, Germany
| | | | - Thomas Dresbach
- Department of Anatomy and Cell Biology, Center of Anatomy, Georg August University Göttingen, Göttingen, Germany
| | | | - Martin Korte
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
| | | | - Martin Rothkegel
- Cellular Neurobiology, Zoological Institute, TU Braunschweig, Braunschweig, Germany
- * E-mail:
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21
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Molecular characterization, tissue distribution, subcellular localization and actin-sequestering function of a thymosin protein from silkworm. PLoS One 2012; 7:e31040. [PMID: 22383992 PMCID: PMC3284464 DOI: 10.1371/journal.pone.0031040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2011] [Accepted: 12/30/2011] [Indexed: 02/07/2023] Open
Abstract
We identified a novel gene encoding a Bombyx mori thymosin (BmTHY) protein from a cDNA library of silkworm pupae, which has an open reading frame (ORF) of 399 bp encoding 132 amino acids. It was found by bioinformatics that BmTHY gene consisted of three exons and two introns and BmTHY was highly homologous to thymosin betas (Tβ). BmTHY has a conserved motif LKHTET with only one amino acid difference from LKKTET, which is involved in Tβ binding to actin. A His-tagged BmTHY fusion protein (rBmTHY) with a molecular weight of approximately 18.4 kDa was expressed and purified to homogeneity. The purified fusion protein was used to produce anti-rBmTHY polyclonal antibodies in a New Zealand rabbit. Subcellular localization revealed that BmTHY can be found in both Bm5 cell (a silkworm ovary cell line) nucleus and cytoplasm but is primarily located in the nucleus. Western blotting and real-time RT-PCR showed that during silkworm developmental stages, BmTHY expression levels are highest in moth, followed by instar larvae, and are lowest in pupa and egg. BmTHY mRNA was universally distributed in most of fifth-instar larvae tissues (except testis). However, BmTHY was expressed in the head, ovary and epidermis during the larvae stage. BmTHY formed complexes with actin monomer, inhibited actin polymerization and cross-linked to actin. All the results indicated BmTHY might be an actin-sequestering protein and participate in silkworm development.
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22
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Yun SP, Ryu JM, Jang MW, Han HJ. Interaction of profilin-1 and F-actin via a β-arrestin-1/JNK signaling pathway involved in prostaglandin E(2)-induced human mesenchymal stem cells migration and proliferation. J Cell Physiol 2011; 226:559-71. [PMID: 20717968 DOI: 10.1002/jcp.22366] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Although many previous reports have examined the function of prostaglandin E(2) (PGE(2)) in the migration and proliferation of various cell types, the role of the actin cytoskeleton in human mesenchymal stem cells (hMSCs) migration and proliferation has not been reported. The present study examined the involvement of profilin-1 (Pfn-1) and filamentous-actin (F-actin) in PGE(2)-induced hMSC migration and proliferation and its related signal pathways. PGE(2) (10(-6) M) increased both cell migration and proliferation, and also increased E-type prostaglandin receptor 2 (EP2) mRNA expression, β-arrestin-1 phosphorylation, and c-Jun N-terminal kinase (JNK) phosphorylation. Small interfering RNA (siRNA)-mediated knockdown of β-arrestin-1 and JNK (-1, -2, -3) inhibited PGE(2)-induced growth of hMSCs. PGE(2) also activated Pfn-1, which was blocked by JNK siRNA, and induced F-actin level and organization. Downregulation of Pfn-1 by siRNA decreased the level and organization of F-actin. In addition, specific siRNA for TRIO and F-actin-binding protein (TRIOBP) reduced the PGE(2)-induced increase in hMSC migration and proliferation. Together, these experimental data demonstrate that PGE(2) partially stimulates hMSCs migration and proliferation by interaction of Pfn-1 and F-actin via EP2 receptor-dependent β-arrestin-1/JNK signaling pathways.
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Affiliation(s)
- Seung Pil Yun
- Department of Veterinary Physiology, College of Veterinary Medicine, Biotherapy Human Resources Center (BK21), Chonnam National University, Gwangju, Korea
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23
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Castano E, Philimonenko VV, Kahle M, Fukalová J, Kalendová A, Yildirim S, Dzijak R, Dingová-Krásna H, Hozák P. Actin complexes in the cell nucleus: new stones in an old field. Histochem Cell Biol 2010; 133:607-26. [PMID: 20443021 DOI: 10.1007/s00418-010-0701-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2010] [Indexed: 01/13/2023]
Abstract
Actin is a well-known protein that has shown a myriad of activities in the cytoplasm. However, recent findings of actin involvement in nuclear processes are overwhelming. Actin complexes in the nucleus range from very dynamic chromatin-remodeling complexes to structural elements of the matrix with single partners known as actin-binding proteins (ABPs). This review summarizes the recent findings of actin-containing complexes in the nucleus. Particular attention is given to key processes like chromatin remodeling, transcription, DNA replication, nucleocytoplasmic transport and to actin roles in nuclear architecture. Understanding the mechanisms involving ABPs will definitely lead us to the principles of the regulation of gene expression performed via concerting nuclear and cytoplasmic processes.
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Affiliation(s)
- E Castano
- Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the ASCR, Prague, Czech Republic
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24
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Zou L, Hazan R, Roy P. Profilin-1 overexpression restores adherens junctions in MDA-MB-231 breast cancer cells in R-cadherin-dependent manner. ACTA ACUST UNITED AC 2010; 66:1048-56. [PMID: 19593789 DOI: 10.1002/cm.20407] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Profilin-1 (Pfn1), a ubiquitously expressed actin-binding protein, is downregulated in several different types of adenocarcinoma and elicits tumor-suppressive effect on breast cancer cell lines. MDA-MB-231 (MDA-231), a breast cancer cell line that displays all the characteristics of post-epithelial-to-mesenchymal transition and does not form cell-cell adhesion, can be reverted to an epithelioid phenotype by Pfn1 overexpression. This morphological transition is caused by restoration of adherens junctions (AJ) requiring Pfn1's interaction with actin. Pfn1 overexpression increases the expression level of R-cadherin (a type of cadherin that is endogenously expressed in the parental cell line) and restores AJ in MDA-231 cells in R-cadherin-dependent manner. These findings highlight important role of Pfn1 in the regulation of epithelial cell-cell adhesion.
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Affiliation(s)
- Li Zou
- Department of Bioengineering, University of Pittsburgh, 306 Center for Bioengineering, 300 Technology Drive, Pittsburgh, PA 15219, USA
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25
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Veniere S, Ampe C, Vandekerckhove J, Lambrechts A. The interaction of proline-rich ligands with profilin probed with an enzyme-linked immunosorbent assay. ACTA ACUST UNITED AC 2009; 14:350-9. [PMID: 19403918 DOI: 10.1177/1087057109332594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To detect interactions of different proline-rich ligands with profilins, the authors developed a simple analytical antibody-based screening method. Profilin I or profilin IIa was coated in microplates, and ligand binding was monitored via antibody detection. Using purified components, the authors show that the assay is very sensitive as nanomolar concentrations of recombinant profilin ligands can be used. They further apply this technique to detect interaction of profilin with various proline-rich partners, either endogenously present or ectopically expressed as tagged fusions, using lysates. With this assay, the authors identify Shootin1 as a novel profilin IIa partner. In addition, they demonstrate that this assay can be used for studying competition or ternary complex formation. In conclusion, they developed a sensitive, easy-to-use, and versatile method for the study of the interaction between profilin and different ligands.
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Affiliation(s)
- Sylvie Veniere
- Department of Medical Protein Research, VIB, Ghent, Belgium
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26
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Abstract
Thirty years after its initial characterization and more than 1000 publications listed in PubMed describing its properties, the small (ca 15 kDa) protein profilin continues to surprise us with new, recently discovered functions. Originally described as an actin-binding protein, profilin has now been shown to interact with more than a dozen proteins in mammalian cells. Some of the more recently described and intriguing interactions are within neurons involving a neuronal profilin family member. Profilin is now regarded as a regulator of various cellular processes such as cytoskeletal dynamics, membrane trafficking and nuclear transport. Profilin is a necessary element in key steps of neuronal differentiation and synaptic plasticity, and embodies properties postulated for a synaptic tag. These findings identify profilin as an important factor linking cellular and behavioural plasticity in neural circuits.
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Affiliation(s)
- Andreas Birbach
- Medical University of Vienna, Währingerstrasse 13a, A-1090 Vienna, Austria.
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27
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Sekerková G, Zheng L, Mugnaini E, Bartles JR. Espin actin-cytoskeletal proteins are in rat type I spiral ganglion neurons and include splice-isoforms with a functional nuclear localization signal. J Comp Neurol 2008; 509:661-76. [PMID: 18551532 DOI: 10.1002/cne.21755] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The espins are Ca(2+)-resistant actin-bundling proteins that are enriched in hair cell stereocilia and sensory cell microvilli. Here, we report a novel localization of espins to a large proportion of rat type I spiral ganglion neurons (SGNs) and their projections to the cochlear nucleus (CN). Moreover, we show that a fraction of these espins is in the nucleus of SGNs owing to the presence of splice-isoforms that contain a functional nuclear localization signal (NLS). Espin antibody labeled approximately 83% of type I SGNs, and the labeling intensity increased dramatically during early postnatal development. Type II SGNs and vestibular ganglion neurons were unlabeled. In the CN, espin-positive auditory nerve fibers showed a projection pattern typical of type I SGNs, with intense labeling in the nerve root region and posteroventral CN (PVCN). The anteroventral CN (AVCN) showed moderate labeling, whereas the dorsal CN showed weak labeling that was restricted to the deep layer. Espin-positive synaptic terminals were enriched around nerve root neurons and octopus cells in the PVCN and were also found on globular bushy cells and multipolar neurons in the PVCN and AVCN. SGNs expressed multiple espin transcripts and proteins, including splice-isoforms that contain a nonapeptide, which is rich in positively charged amino acids and creates a bipartite NLS. The nonapeptide was necessary to target espin isoforms to the nucleus and was sufficient to target an unrelated protein to the nucleus when joined with the upstream di-arginine-containing octapeptide. The presence of cytoplasmic and nuclear espins in SGNs suggests additional roles for espins in auditory neuroscience.
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Affiliation(s)
- Gabriella Sekerková
- Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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28
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Nie Z, Xu J, Chen J, Lv Z, Wang D, Sheng Q, Wu Y, Wang X, Wu X, Zhang Y. Expression analysis and characteristics of profilin gene from silkworm, Bombyx mori. Appl Biochem Biotechnol 2008; 158:59-71. [PMID: 18633732 DOI: 10.1007/s12010-008-8302-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2008] [Accepted: 06/17/2008] [Indexed: 11/24/2022]
Abstract
A recombinant Bombyx mori profilin protein (rBmPFN) was overexpressed in Escherichia coli BL21. Purified rBmPFN was used to generate anti-BmPFN polyclonal antibody, which were used to determine the subcellular localization of BmPFN. Immunostaining indicated that profilin can be found in both the nucleus and cytoplasm but is primarily located in the cytoplasm. Real-time RT-PCR and Western blot analyses indicated that, during the larvae stage, profilin expression levels are highest in the silk gland, followed by the gonad, and are lowest in the fatty body. Additionally, BmPFN expression begins during the egg stage, increases during the larvae stage, reaches a peak during the pupa stage, and decreases significantly in the moth. Therefore, we propose that BmPFN may play an important role during larva stage development, especially in the silk gland.
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Affiliation(s)
- Zuoming Nie
- Institute of Biochemistry, College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou, China
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29
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Chan CML, Wong SCC, Lam MYY, Hui EP, Chan JKC, Lo ESF, Cheuk W, Wong MCK, Tsao SW, Chan ATC. Proteomic comparison of nasopharyngeal cancer cell lines C666-1 and NP69 identifies down-regulation of annexin II and beta2-tubulin for nasopharyngeal carcinoma. Arch Pathol Lab Med 2008; 132:675-83. [PMID: 18384219 DOI: 10.5858/2008-132-675-pconcc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2007] [Indexed: 11/06/2022]
Abstract
CONTEXT Nasopharyngeal carcinoma (NPC), common in southern China and North Africa, has a complex etiology involving interplay between viral, environmental, and hereditary factors and is almost constantly associated with the Epstein-Barr virus. Since the prognosis of locally advanced and metastatic diseases is poor, increased understanding of the pathogenesis of NPC would be important for discovering novel markers for patients' management. OBJECTIVES To compare the proteomic expression profile between an Epstein-Barr virus-associated NPC cell line (C666-1) and a normal NP cell line (NP69). The proteins with differential expression were analyzed in 40 undifferentiated NPC paraffin-embedded specimens. DESIGN Differentially expressed proteins discovered between the two cell lines were identified by mass spectrometry. After confirmation by immunocytochemical staining, their expression in patient samples was measured using 40 pairs of undifferentiated NPCs together with their adjacent normal epithelia. RESULTS Proteomic findings indicated that adenosine triphosphate synthase alpha chain was up-regulated, whereas annexin II, annexin V, beta(2)-tubulin, and profilin 1 were down-regulated. After confirming the results in agar-processed cell lines, annexin II and beta(2)-tubulin expression were found to be lower in tumor cells than in adjacent normal epithelial cells in 100% and 90% of the patients' specimens, respectively. Finally, annexin II down-regulation was positively associated with lymph node metastasis, suggesting that it may be a prognostic factor in NPC. CONCLUSIONS The results suggest that annexin II and beta(2)-tubulin down-regulation is important in NPC formation and may represent potential targets for further investigations.
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Affiliation(s)
- Charles M L Chan
- Department of Clinical Oncology, Sir Y. K. Pao Centre for Cancer, Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong Special Administrative Region, China
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30
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Vartiainen MK. Nuclear actin dynamics--from form to function. FEBS Lett 2008; 582:2033-40. [PMID: 18423404 DOI: 10.1016/j.febslet.2008.04.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/28/2008] [Accepted: 04/09/2008] [Indexed: 01/10/2023]
Abstract
Cell biological functions of actin have recently expanded from cytoplasm to nucleus, with actin implicated in such diverse processes as gene expression, transcription factor regulation and intranuclear motility. Actin in the nucleus seems to behave differently than in the cytoplasm, raising new questions regarding the molecular mechanisms by which actin functions in cells. In this review, I will discuss dynamic properties of nuclear actin that are related to its polymerization cycle and nucleocytoplasmic shuttling. By comparing the behaviour of nuclear and cytoplasmic actin and their regulators, I try to dissect the underlying differences of these equally important cellular actin pools.
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Affiliation(s)
- Maria K Vartiainen
- Research Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Viikinkaari 9, 00014 Helsinki, Finland.
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Abstract
We previously reported a transgenic Caenorhabditis elegans model for tauopathies in which expression of human tau in neurons caused insoluble phosphorylated tau accumulation, neurodegeneration and uncoordinated movement (Unc). To identify genes participating in tau neurotoxicity, we conducted a forward genetic screen for mutations that ameliorate tau-induced uncoordination. The recessive mutation sut-1(bk79) partially suppresses the Unc phenotype, tau aggregation and neurodegenerative changes caused by tau. We identified the sut-1 gene and found it encodes a novel protein. We conducted a yeast two hybrid screen to identify SUT-1 binding partners and found UNC-34, the C. elegans homolog of the cytoskeletal regulatory protein Enabled (ENA). In vitro protein binding assays and genetic studies validated the interaction between SUT-1 and UNC-34. The SUT-1/UNC-34 protein-protein interaction plays a role in both the normal function of UNC-34 and in the tau-induced phenotype. Thus, we have found a conserved molecular pathway participating in tau neurotoxicity in C. elegans.
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Affiliation(s)
- Brian C Kraemer
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.
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32
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Abstract
Profilins are small proteins involved in actin dynamics. In accordance with this function, they are found in all eukaryotes and are structurally highly conserved. However, their precise role in regulating actin-related functions is just beginning to emerge. This article recapitulates the wealth of information on structure, expression and functions accumulated on profilins from many different organisms in the 30 years after their discovery as actin-binding proteins. Emphasis is given to their interaction with a plethora of many different ligands in the cytoplasm as well as in the nucleus, which is considered the basis for their various activities and the significance of the tissue-specific expression of profilin isoforms.
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Affiliation(s)
- B M Jockusch
- Cell Biology, Zoological Institute, Technical University of Braunschweig, 38092 Braunschweig, Germany.
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33
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Ding Z, Lambrechts A, Parepally M, Roy P. Silencing profilin-1 inhibits endothelial cell proliferation, migration and cord morphogenesis. J Cell Sci 2006; 119:4127-37. [PMID: 16968742 DOI: 10.1242/jcs.03178] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Expression of several actin-binding proteins including profilin-1 is up-regulated during capillary morphogenesis of endothelial cells, the biological significance of which remains unknown. Specifically, we hypothesized that profilin-1 is important for endothelial migration and proliferation. In this study, we suppressed profilin-1 expression in human umbilical vein endothelial cells by RNA-interference. Gene silencing of profilin-1 led to significant reduction in the formation of actin filaments and focal adhesions. Loss of profilin-1 expression was also associated with reduced dynamics of cell-cell adhesion. Data from both wound-healing experiments and time-lapse imaging of individual cells showed inhibition of cell migration when profilin-1 expression was suppressed. Cells lacking profilin-1 exhibited defects in membrane protrusion, both in terms of its magnitude and directional persistence. Furthermore, loss of profilin-1 expression inhibited cell growth without compromising cell survival, at least in the short-term, thus suggesting that profilin-1 also plays an important role in endothelial proliferation as hypothesized. Finally, silencing profilin-1 expression suppressed matrigel-induced early cord morphogenesis of endothelial cells. Taken together, our data suggest that profilin-1 may play important role in biological events that involve endothelial proliferation, migration and morphogenesis.
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Affiliation(s)
- Zhijie Ding
- Department of Bioengineering, University of Pittsburgh, 749 Benedum Hall, 3700 O'Hara Street, Pittsburgh, PA 15261, USA
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34
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Birbach A, Verkuyl JM, Matus A. Reversible, activity-dependent targeting of profilin to neuronal nuclei. Exp Cell Res 2006; 312:2279-87. [PMID: 16716297 DOI: 10.1016/j.yexcr.2006.03.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2005] [Revised: 03/17/2006] [Accepted: 03/23/2006] [Indexed: 01/28/2023]
Abstract
The actin cytoskeleton in pyramidal neurons plays a major role in activity-dependent processes underlying neuronal plasticity. The small actin-binding protein profilin shows NMDA receptor-dependent accumulation in dendritic spines, which is correlated with suppression of actin dynamics and long-term stabilization of synaptic morphology. Here we show that following NMDA receptor activation profilin also accumulates in the nucleus of hippocampal neurons via a process involving rearrangement of the actin cytoskeleton. This simultaneous targeting to dendritic spines and the cell nucleus suggests a novel mechanism of neuronal plasticity in which profilin both tags activated synapses and influences nuclear events.
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Affiliation(s)
- Andreas Birbach
- Friedrich Miescher Institute, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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35
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De Ganck A, Hubert T, Van Impe K, Geelen D, Vandekerckhove J, De Corte V, Gettemans J. A monopartite nuclear localization sequence regulates nuclear targeting of the actin binding protein myopodin. FEBS Lett 2005; 579:6673-80. [PMID: 16309678 DOI: 10.1016/j.febslet.2005.10.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Revised: 09/09/2005] [Accepted: 10/27/2005] [Indexed: 11/29/2022]
Abstract
Myopodin is an actin bundling protein that shuttles between nucleus and cytoplasm in response to cell stress or during differentiation. Here, we show that the myopodin sequence 58KKRRRRARK66, when tagged to either enhanced green fluorescent protein (EGFP) or to enhanced cyan fluorescent protein-CapG (ECFPCapG), is able to target these proteins to the nucleolus in HeLa or HEK293T cells. By contrast, 58KKRR61-ECFP-CapG accumulates in the nucleus. Mutation of 58KKRRRRARK66 into alanine residues blocks myopodin nuclear import and promotes formation of cytoplasmic actin filaments. A second putative nuclear localization sequence, 612KTSKKKGKK620, displays much weaker activity in a heterologous context, and appears not to be functional in the full length protein. Thus myopodin nuclear translocation is dependent on a monopartite nuclear localization sequence.
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Affiliation(s)
- Ariane De Ganck
- Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology (V.I.B.), Ghent University, Faculty of Medicine and Health Sciences, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
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36
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Gettemans J, Van Impe K, Delanote V, Hubert T, Vandekerckhove J, De Corte V. Nuclear actin-binding proteins as modulators of gene transcription. Traffic 2005; 6:847-57. [PMID: 16138899 DOI: 10.1111/j.1600-0854.2005.00326.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dynamic transformations in the organization of the cellular microfilament system are the driving force behind fundamental biological processes such as cellular motility, cytokinesis, wound healing and secretion. Eukaryotic cells express a plethora of actin-binding proteins (ABPs) allowing cells to control the organization of the actin cytoskeleton in a flexible manner. These structural proteins were, not surprisingly, originally described as (major) constituents of the cytoplasm. However, in recent years, there has been a steady flow of reports detailing not only translocation of ABPs into and out of the nucleus but also describing their role in the nuclear compartment. This review focuses on recent developments pertaining to nucleocytoplasmic transport of ABPs, including their mode of translocation and nuclear function. In particular, evidence that structurally and functionally unrelated cytoplasmic ABPs regulate transcription activation by various nuclear (steroid hormone) receptors is steadily accruing. Furthermore, the recent finding that actin is a necessary component of the RNA polymerase II-containing preinitiation complex opens up new opportunities for nuclear ABPs in gene transcription regulation.
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Affiliation(s)
- Jan Gettemans
- Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium.
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