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Petit F, Longoni M, Wells J, Maser RS, Bogenschutz EL, Dysart MJ, Contreras HTM, Frénois F, Pober BR, Clark RD, Giampietro PF, Ropers HH, Hu H, Loscertales M, Wagner R, Ai X, Brand H, Jourdain AS, Delrue MA, Gilbert-Dussardier B, Devisme L, Keren B, McCulley DJ, Qiao L, Hernan R, Wynn J, Scott TM, Calame DG, Coban-Akdemir Z, Hernandez P, Hernandez-Garcia A, Yonath H, Lupski JR, Shen Y, Chung WK, Scott DA, Bult CJ, Donahoe PK, High FA. PLS3 missense variants affecting the actin-binding domains cause X-linked congenital diaphragmatic hernia and body-wall defects. Am J Hum Genet 2023; 110:1787-1803. [PMID: 37751738 PMCID: PMC10577083 DOI: 10.1016/j.ajhg.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/28/2023] Open
Abstract
Congenital diaphragmatic hernia (CDH) is a relatively common and genetically heterogeneous structural birth defect associated with high mortality and morbidity. We describe eight unrelated families with an X-linked condition characterized by diaphragm defects, variable anterior body-wall anomalies, and/or facial dysmorphism. Using linkage analysis and exome or genome sequencing, we found that missense variants in plastin 3 (PLS3), a gene encoding an actin bundling protein, co-segregate with disease in all families. Loss-of-function variants in PLS3 have been previously associated with X-linked osteoporosis (MIM: 300910), so we used in silico protein modeling and a mouse model to address these seemingly disparate clinical phenotypes. The missense variants in individuals with CDH are located within the actin-binding domains of the protein but are not predicted to affect protein structure, whereas the variants in individuals with osteoporosis are predicted to result in loss of function. A mouse knockin model of a variant identified in one of the CDH-affected families, c.1497G>C (p.Trp499Cys), shows partial perinatal lethality and recapitulates the key findings of the human phenotype, including diaphragm and abdominal-wall defects. Both the mouse model and one adult human male with a CDH-associated PLS3 variant were observed to have increased rather than decreased bone mineral density. Together, these clinical and functional data in humans and mice reveal that specific missense variants affecting the actin-binding domains of PLS3 might have a gain-of-function effect and cause a Mendelian congenital disorder.
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Affiliation(s)
- Florence Petit
- Clinique de Génétique, CHU de Lille, Lille, France; EA7364 RADEME, Université de Lille, Lille, France
| | - Mauro Longoni
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Harvard Medical School, Boston, MA, USA
| | | | | | | | - Matthew J Dysart
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA
| | - Hannah T M Contreras
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA
| | | | - Barbara R Pober
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA
| | - Robin D Clark
- Division of Genetics, Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | | | - Hilger H Ropers
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Hao Hu
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Maria Loscertales
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Richard Wagner
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Harvard Medical School, Boston, MA, USA; Department of Pediatric Surgery, University Hospital Leipzig, Leipzig, Germany
| | - Xingbin Ai
- Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA
| | - Harrison Brand
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | | | | | | | | | - Boris Keren
- Département de Génétique, Hôpital Pitié Salpétrière, CHU de Paris, Paris, France
| | - David J McCulley
- Department of Pediatrics, University of California, San Diego, San Diego, CA, USA
| | - Lu Qiao
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Rebecca Hernan
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Julia Wynn
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Tiana M Scott
- Department of Microbiology and Molecular Biology, College of Life Sciences, Brigham Young University, Provo, UT, USA
| | - Daniel G Calame
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Division of Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA
| | - Zeynep Coban-Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Human Genetics Center, Department of Epidemiology, Human Genetics, and Environmental Sciences, School of Public Health, the University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Patricia Hernandez
- IDDRC/TCC, Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | | | - Hagith Yonath
- Internal Medicine A and Genetics Institute, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Yufeng Shen
- Department of Systems Biology, Columbia University, New York, NY, USA
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Texas Children's Hospital, Houston, TX, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | | | - Patricia K Donahoe
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Harvard Medical School, Boston, MA, USA
| | - Frances A High
- Pediatric Surgical Research Laboratories, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Harvard Medical School, Boston, MA, USA; Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA; Department of Surgery, Boston Children's Hospital, Boston, MA, USA.
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Cornelison R, Marrah L, Fierti A, Piczak C, Glowczyk M, Tajammal A, Lynch S, Li H. The Potential for Targeting AVIL and Other Actin-Binding Proteins in Rhabdomyosarcoma. Int J Mol Sci 2023; 24:14196. [PMID: 37762498 PMCID: PMC10531751 DOI: 10.3390/ijms241814196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
Rhabdomyosarcoma (RMS) is the most common pediatric soft-tissue cancer with a survival rate below 27% for high-risk children despite aggressive multi-modal therapeutic interventions. After decades of research, no targeted therapies are currently available. Therapeutically targeting actin-binding proteins, although promising, has historically been challenging. Recent advances have made this possibility more salient, including our lab's identification of advillin (AVIL), a novel oncogenic actin-binding protein that plays a role in many cytoskeletal functions. AVIL is overexpressed in many RMS cell lines, patient-derived xenograft models, and a cohort of 30 clinical samples of both the alveolar (ARMS) and embryonal (ERMS) subtypes. Overexpression of AVIL in mesenchymal stem cells induces neoplastic transformation both in vitro and in vivo, and reversing overexpression through genetic modulation reverses the transformation. This suggests a critical role of AVIL in RMS tumorigenesis and maintenance. As an actin-binding protein, AVIL would not traditionally be considered a druggable target. This perspective will address the feasibility of targeting differentially expressed actin-binding proteins such as AVIL therapeutically, and how critical cell infrastructure can be damaged in a cancer-specific manner.
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Affiliation(s)
| | | | | | | | | | | | | | - Hui Li
- Department of Pathology, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
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Baroni L, Abreu-Filho PG, Pereira LM, Nagl M, Yatsuda AP. Recombinant actin-depolymerizing factor of the apicomplexan Neospora caninum (NcADF) is susceptible to oxidation. Front Cell Infect Microbiol 2022; 12:952720. [PMID: 36601306 PMCID: PMC9806845 DOI: 10.3389/fcimb.2022.952720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/21/2022] [Indexed: 12/24/2022] Open
Abstract
Neospora caninum is a member of Apicomplexa Phylum and the causative agent of neosporosis, a disease responsible for abortions in cattle. Apicomplexan parasites have a limited set of actin-binding proteins conducting the regulation of the dynamics of nonconventional actin. The parasite actin-based motility is implicated in the parasite invasion process in the host cell. Once no commercial strategy for the neosporosis control is available, the interference in the parasite actin function may result in novel drug targets. Actin-depolymerization factor (ADF) is a member of the ADF/cofilin family, primarily known for its function in actin severing and depolymerization. ADF/cofilins are versatile proteins modulated by different mechanisms, including reduction and oxidation. In apicomplexan parasites, the mechanisms involved in the modulation of ADF function are barely explored and the effects of oxidation in the protein are unknown so far. In this study, we used the oxidants N-chlorotaurine (NCT) and H2O2 to investigate the susceptibility of the recombinant N. caninum ADF (NcADF) to oxidation. After exposing the protein to either NCT or H2O2, the dimerization status and cysteine residue oxidation were determined. Also, the interference of NcADF oxidation in the interaction with actin was assessed. The treatment of the recombinant protein with oxidants reversibly induced the production of dimers, indicating that disulfide bonds between NcADF cysteine residues were formed. In addition, the exposure of NcADF to NCT resulted in more efficient oxidation of the cysteine residues compared to H2O2. Finally, the oxidation of NcADF by NCT reduced the ability of actin-binding and altered the function of NcADF in actin polymerization. Altogether, our results clearly show that recombinant NcADF is sensitive to redox conditions, indicating that the function of this protein in cellular processes involving actin dynamics may be modulated by oxidation.
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Affiliation(s)
- Luciana Baroni
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Péricles Gama Abreu-Filho
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Luiz Miguel Pereira
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Markus Nagl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck, Innsbruck, Austria
| | - Ana Patricia Yatsuda
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil,*Correspondence: Ana Patricia Yatsuda,
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Gasilina A, Yoon HY, Jian X, Luo R, Randazzo PA. A lysine-rich cluster in the N-BAR domain of ARF GTPase-activating protein ASAP1 is necessary for binding and bundling actin filaments. J Biol Chem 2022; 298:101700. [PMID: 35143843 PMCID: PMC8902617 DOI: 10.1016/j.jbc.2022.101700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/25/2022] [Accepted: 01/28/2022] [Indexed: 12/05/2022] Open
Abstract
Actin filament maintenance is critical for both normal cell homeostasis and events associated with malignant transformation. The ADP-ribosylation factor GTPase-activating protein ASAP1 regulates the dynamics of filamentous actin-based structures, including stress fibers, focal adhesions, and circular dorsal ruffles. Here, we have examined the molecular basis for ASAP1 association with actin. Using a combination of structural modeling, mutagenesis, and in vitro and cell-based assays, we identify a putative-binding interface between the N-Bin-Amphiphysin-Rvs (BAR) domain of ASAP1 and actin filaments. We found that neutralization of charges and charge reversal at positions 75, 76, and 79 of ASAP1 reduced the binding of ASAP1 BAR-pleckstrin homology tandem to actin filaments and abrogated actin bundle formation in vitro. In addition, overexpression of actin-binding defective ASAP1 BAR-pleckstrin homology [K75, K76, K79] mutants prevented cellular actin remodeling in U2OS cells. Exogenous expression of [K75E, K76E, K79E] mutant of full-length ASAP1 did not rescue the reduction of cellular actin fibers consequent to knockdown of endogenous ASAP1. Taken together, our results support the hypothesis that the lysine-rich cluster in the N-BAR domain of ASAP1 is important for regulating actin filament organization.
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Affiliation(s)
- Anjelika Gasilina
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA; Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, District of Columbia, USA
| | - Hye-Young Yoon
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Ruibai Luo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
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Gao J, Nakamura F. Actin-Associated Proteins and Small Molecules Targeting the Actin Cytoskeleton. Int J Mol Sci 2022; 23:ijms23042118. [PMID: 35216237 PMCID: PMC8880164 DOI: 10.3390/ijms23042118] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/10/2022] [Accepted: 02/11/2022] [Indexed: 02/06/2023] Open
Abstract
Actin-associated proteins (AAPs) act on monomeric globular actin (G-actin) and polymerized filamentous actin (F-actin) to regulate their dynamics and architectures which ultimately control cell movement, shape change, division; organelle localization and trafficking. Actin-binding proteins (ABPs) are a subset of AAPs. Since actin was discovered as a myosin-activating protein (hence named actin) in 1942, the protein has also been found to be expressed in non-muscle cells, and numerous AAPs continue to be discovered. This review article lists all of the AAPs discovered so far while also allowing readers to sort the list based on the names, sizes, functions, related human diseases, and the dates of discovery. The list also contains links to the UniProt and Protein Atlas databases for accessing further, related details such as protein structures, associated proteins, subcellular localization, the expression levels in cells and tissues, mutations, and pathology. Because the actin cytoskeleton is involved in many pathological processes such as tumorigenesis, invasion, and developmental diseases, small molecules that target actin and AAPs which hold potential to treat these diseases are also listed.
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Lucero D, Dikilitas O, Mendelson MM, Aligabi Z, Islam P, Neufeld EB, Bansal AT, Freeman LA, Vaisman B, Tang J, Combs CA, Li Y, Voros S, Kullo IJ, Remaley AT. Transgelin: A New Gene Involved in LDL Endocytosis Identified by a Genome-wide CRISPR-Cas9 Screen. J Lipid Res 2021; 63:100160. [PMID: 34902367 PMCID: PMC8953622 DOI: 10.1016/j.jlr.2021.100160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 11/18/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022] Open
Abstract
A significant proportion of patients with elevated LDL and a clinical presentation of familial hypercholesterolemia do not carry known genetic mutations associated with hypercholesterolemia, such as defects in the LDL receptor. To identify new genes involved in the cellular uptake of LDL, we developed a novel whole-genome clustered regularly interspaced short palindromic repeat-Cas9 KO screen in HepG2 cells. We identified transgelin (TAGLN), an actin-binding protein, as a potentially new gene involved in LDL endocytosis. In silico validation demonstrated that genetically predicted differences in expression of TAGLN in human populations were significantly associated with elevated plasma lipids (triglycerides, total cholesterol, and LDL-C) in the Global Lipids Genetics Consortium and lipid-related phenotypes in the UK Biobank. In biochemical studies, TAGLN-KO HepG2 cells showed a reduction in cellular LDL uptake, as measured by flow cytometry. In confocal microscopy imaging, TAGLN-KO cells had disrupted actin filaments as well as an accumulation of LDL receptor on their surface because of decreased receptor internalization. Furthermore, TAGLN-KO cells exhibited a reduction in total and free cholesterol content, activation of SREBP2, and a compensatory increase in cholesterol biosynthesis. TAGLN deficiency also disrupted the uptake of VLDL and transferrin, other known cargoes for receptors that depend upon clathrin-mediated endocytosis. Our data suggest that TAGLN is a novel factor involved in the actin-dependent phase of clathrin-mediated endocytosis of LDL. The identification of novel genes involved in the endocytic uptake of LDL may improve the diagnosis of hypercholesterolemia and provide future therapeutic targets for the prevention of cardiovascular disease.
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Affiliation(s)
- Diego Lucero
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Ozan Dikilitas
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA; Mayo Clinician-Investigator Training Program, Mayo Clinic, Rochester, MN, USA
| | - Michael M Mendelson
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Zahra Aligabi
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Promotto Islam
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Edward B Neufeld
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Aruna T Bansal
- Acclarogen Ltd, St John's Innovation Centre, Cambridge, United Kingdom
| | - Lita A Freeman
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Boris Vaisman
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jingrong Tang
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Christian A Combs
- NHLBI Light Microscopy Facility, National Institutes of Health, Bethesda, MD, USA
| | - Yuesheng Li
- DNA Sequencing and Genomics Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Iftikhar J Kullo
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA; Gonda Vascular Center, Mayo Clinic, Rochester, MN, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Laboratory, Translational Vascular Medicine Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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Kubota H, Ogawa H, Miyazaki M, Ishii S, Oyama K, Kawamura Y, Ishiwata S, Suzuki M. Microscopic Temperature Control Reveals Cooperative Regulation of Actin-Myosin Interaction by Drebrin E. Nano Lett 2021; 21:9526-9533. [PMID: 34751025 DOI: 10.1021/acs.nanolett.1c02955] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Drebrin E is a regulatory protein of intracellular force produced by actomyosin complexes, that is, myosin molecular motors interacting with actin filaments. The expression level of drebrin E in nerve cells decreases as the animal grows, suggesting its pivotal but unclarified role in neuronal development. Here, by applying the microscopic heat pulse method to actomyosin motility assay, the regulatory mechanism is examined from the room temperature up to 37 °C without a thermal denaturing of proteins. We show that the inhibition of actomyosin motility by drebrin E is eliminated immediately and reversibly during heating and depends on drebrin E concentration. The direct observation of quantum dot-labeled drebrin E implies its stable binding to actin filaments during the heat-induced sliding. Our results suggest that drebrin E allosterically modifies the actin filament structure to regulate cooperatively the actomyosin activity at the maintained in vivo body temperature.
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Affiliation(s)
- Hiroaki Kubota
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
- Department of Microbiology, Tokyo Metropolitan Institute of Public Health, 3-24-1 Hyakunincho, Shinjuku-ku, Tokyo 169-0073, Japan
| | - Hiroyuki Ogawa
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Makito Miyazaki
- Hakubi Center for Advanced Research, Kyoto University, Yoshida-honmachi, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Physics, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Institut Curie, PSL Research University, CNRS, UMR 144, Paris F-75005, France
| | - Shuya Ishii
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan
| | - Kotaro Oyama
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
- Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan
| | - Yuki Kawamura
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Shin'ichi Ishiwata
- Department of Physics, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Madoka Suzuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Vasilev F, Ezhova Y, Chun JT. Signaling Enzymes and Ion Channels Being Modulated by the Actin Cytoskeleton at the Plasma Membrane. Int J Mol Sci 2021; 22:ijms221910366. [PMID: 34638705 PMCID: PMC8508623 DOI: 10.3390/ijms221910366] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/23/2021] [Accepted: 09/23/2021] [Indexed: 02/06/2023] Open
Abstract
A cell should deal with the changing external environment or the neighboring cells. Inevitably, the cell surface receives and transduces a number of signals to produce apt responses. Typically, cell surface receptors are activated, and during this process, the subplasmalemmal actin cytoskeleton is often rearranged. An intriguing point is that some signaling enzymes and ion channels are physically associated with the actin cytoskeleton, raising the possibility that the subtle changes of the local actin cytoskeleton can, in turn, modulate the activities of these proteins. In this study, we reviewed the early and new experimental evidence supporting the notion of actin-regulated enzyme and ion channel activities in various cell types including the cells of immune response, neurons, oocytes, hepatocytes, and epithelial cells, with a special emphasis on the Ca2+ signaling pathway that depends on the synthesis of inositol 1,4,5-trisphosphate. Some of the features that are commonly found in diverse cells from a wide spectrum of the animal species suggest that fine-tuning of the activities of the enzymes and ion channels by the actin cytoskeleton may be an important strategy to inhibit or enhance the function of these signaling proteins.
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Affiliation(s)
- Filip Vasilev
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), 900 Rue St Denis, Montreal, QC H2X 0A9, Canada
- Correspondence: (F.V.); (J.T.C.); Tel.: +1-514-249-5862 (F.V.); +39-081-583-3407 (J.T.C.)
| | - Yulia Ezhova
- Maisonneuve-Rosemont Hospital Research Centre, University of Montreal, Montreal, QC H1T 2M4, Canada;
| | - Jong Tai Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121 Napoli, Italy
- Correspondence: (F.V.); (J.T.C.); Tel.: +1-514-249-5862 (F.V.); +39-081-583-3407 (J.T.C.)
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Cornelius J, Rottner K, Korte M, Michaelsen-Preusse K. Cortactin Contributes to Activity-Dependent Modulation of Spine Actin Dynamics and Spatial Memory Formation. Cells 2021; 10:cells10071835. [PMID: 34360003 PMCID: PMC8303107 DOI: 10.3390/cells10071835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/16/2021] [Indexed: 01/21/2023] Open
Abstract
Postsynaptic structures on excitatory neurons, dendritic spines, are actin-rich. It is well known that actin-binding proteins regulate actin dynamics and by this means orchestrate structural plasticity during the development of the brain, as well as synaptic plasticity mediating learning and memory processes. The actin-binding protein cortactin is localized to pre- and postsynaptic structures and translocates in a stimulus-dependent manner between spines and the dendritic compartment, thereby indicating a crucial role for synaptic plasticity and neuronal function. While it is known that cortactin directly binds F-actin, the Arp2/3 complex important for actin nucleation and branching as well as other factors involved in synaptic plasticity processes, its precise role in modulating actin remodeling in neurons needs to be deciphered. In this study, we characterized the general neuronal function of cortactin in knockout mice. Interestingly, we found that the loss of cortactin leads to deficits in hippocampus-dependent spatial memory formation. This impairment is correlated with a prominent dysregulation of functional and structural plasticity. Additional evidence shows impaired long-term potentiation in cortactin knockout mice together with a complete absence of structural spine plasticity. These phenotypes might at least in part be explained by alterations in the activity-dependent modulation of synaptic actin in cortactin-deficient neurons.
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Affiliation(s)
- Jonas Cornelius
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
| | - Klemens Rottner
- Research Group Molecular Cell Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany;
- Division of Molecular Cell Biology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
- Research Group Neuroinflammation and Neurodegeneration, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
| | - Kristin Michaelsen-Preusse
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany; (J.C.); (M.K.)
- Correspondence:
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10
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Persson K, Backman L. Structural and functional characterization of a plant alpha-actinin. FEBS Open Bio 2021. [PMID: 34110107 PMCID: PMC8329775 DOI: 10.1002/2211-5463.13222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 06/01/2021] [Accepted: 06/09/2021] [Indexed: 11/08/2022] Open
Abstract
The Australian tree malletwood (Rhodamnia argentea) is unique. The genome of malletwood is the only known plant genome that contains a gene coding for an α‐actinin‐like protein. Several organisms predating the animal‐plant bifurcation express an α‐actinin or α‐actinin‐like protein. Therefore, it appears that plants in general, but not malletwood, have lost the α‐actinin or α‐actinin‐like gene during evolution. In order to characterize its structure and function, we synthesized the gene and expressed the recombinant R. argentea protein. The results clearly show that this protein has all properties of genuine α‐actinin. The N‐terminal actin‐binding domain (ABD), with two calponin homology motifs, is very similar to the ABD of any α‐actinin. The C‐terminal calmodulin‐like domain, as well as the intervening rod domain, are also similar to the corresponding regions in other α‐actinins. The R. argentea α‐actinin‐like protein dimerises in solution and thereby can cross‐link actin filaments. Based on these results, we believe the R. argentea protein represents a genuine α‐actinin, making R. argentea unique in the plant world.
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Affiliation(s)
| | - Lars Backman
- Department of Chemistry, Umeå University, Sweden
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11
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Li X, Yao Y, Liu T, Gu K, Han Q, Zhang W, Ayala GJ, Liu Y, Na H, Yu J, Zhang F, Mayo KH, Su J. Actin binding to galectin-13/placental protein-13 occurs independently of the galectin canonical ligand binding site. Glycobiology 2021; 31:1219-1229. [PMID: 34080003 DOI: 10.1093/glycob/cwab047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/08/2021] [Accepted: 05/19/2021] [Indexed: 01/09/2023] Open
Abstract
The gene for galectin-13 (Gal-13, placental protein 13) is only present in primates, and its low expression level in maternal serum may promote pre-eclampsia. In the present study, we used pull-down experiments and biolayer interferometry to assess the interaction between Gal-13 and actin. These studies uncovered that human Gal-13 (hGal-13) and Saimiri boliviensis boliviensis (sGal-13) strongly bind to α- and β/γ-actin, with Ca2+ and ATP significantly enhancing interactions. This in turn suggests that h/sGal-13 may inhibit myosin-induced contraction when vascular smooth muscle cells undergo polarization. Here, we solved the crystal structure of sGal-13 bound to lactose and found that it exists as a monomer in contrast to hGal-13 that is a dimer. The distribution of sGal-13 in HeLa cells is similar to that of hGal-13, indicating that monomeric Gal-13 is the primary form in cells. Even though sGal-13 also binds to actin, hGal-13 ligand binding site mutants do not influence hGal-13/actin binding, whereas the monomeric mutant C136S/C138S binds to actin more strongly than wild type hGal-13. Overall, our study demonstrates that monomeric Gal-13 binds to actin, an interaction that is independent of the galectin canonical ligand binding site.
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Affiliation(s)
- Xumin Li
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Yuan Yao
- Media Academy, Jilin Engineering Normal University, Changchun, China
| | - Tianhao Liu
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Keqi Gu
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Qiuyu Han
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Wenlu Zhang
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Gabriela Jaramillo Ayala
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Yuhan Liu
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Heya Na
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Jinyi Yu
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Fan Zhang
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
| | - Kevin H Mayo
- Department of Biochemistry, Molecular Biology & Biophysics, 6-155 Jackson Hall, University of Minnesota, 321 Church Street, Minneapolis, MN 55455, U.S.A
| | - Jiyong Su
- Engineering Research Center of Glycoconjugates Ministry of Education, Jilin Provincial Key Laboratory of Chemistry and Biology of Changbai Mountain Natural Drugs, School of Life Sciences, Northeast Normal University, Changchun 130024, China
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12
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Diao M, Huang S. An Update on the Role of the Actin Cytoskeleton in Plasmodesmata: A Focus on Formins. Front Plant Sci 2021; 12:647123. [PMID: 33659020 PMCID: PMC7917184 DOI: 10.3389/fpls.2021.647123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
Cell-to-cell communication in plants is mediated by plasmodesmata (PD) whose permeability is tightly regulated during plant growth and development. The actin cytoskeleton has been implicated in regulating the permeability of PD, but the underlying mechanism remains largely unknown. Recent characterization of PD-localized formin proteins has shed light on the role and mechanism of action of actin in regulating PD-mediated intercellular trafficking. In this mini-review article, we will describe the progress in this area.
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Affiliation(s)
- Min Diao
- iHuman Institute, Shanghai Tech University, Shanghai, China
| | - Shanjin Huang
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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13
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Xu J, Huang Y, Zhao J, Wu L, Qi Q, Liu Y, Li G, Li J, Liu H, Wu H. Cofilin: A Promising Protein Implicated in Cancer Metastasis and Apoptosis. Front Cell Dev Biol 2021; 9:599065. [PMID: 33614640 PMCID: PMC7890941 DOI: 10.3389/fcell.2021.599065] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/06/2021] [Indexed: 12/13/2022] Open
Abstract
Cofilin is an actin-binding protein that regulates filament dynamics and depolymerization. The over-expression of cofilin is observed in various cancers, cofilin promotes cancer metastasis by regulating cytoskeletal reorganization, lamellipodium formation and epithelial-to-mesenchymal transition. Clinical treatment of cancer regarding cofilin has been explored in aspects of tumor cells apoptosis and cofilin related miRNAs. This review addresses the structure and phosphorylation of cofilin and describes recent findings regarding the function of cofilin in regulating cancer metastasis and apoptosis in tumor cells.
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Affiliation(s)
- Jing Xu
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yan Huang
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jimeng Zhao
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Luyi Wu
- Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Qin Qi
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yanan Liu
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Guona Li
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jing Li
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Huirong Liu
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Huangan Wu
- Yueyang Hospital of Integrative Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.,Key Laboratory of Acupuncture and Immunological Effects, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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14
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Mun SA, Park J, Park KR, Lee Y, Kang JY, Park T, Jin M, Yang J, Jun CD, Eom SH. Structural and Biochemical Characterization of EFhd1/Swiprosin-2, an Actin-Binding Protein in Mitochondria. Front Cell Dev Biol 2021; 8:628222. [PMID: 33537316 PMCID: PMC7848108 DOI: 10.3389/fcell.2020.628222] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022] Open
Abstract
Ca2+ regulates several cellular functions, including signaling events, energy production, and cell survival. These cellular processes are mediated by Ca2+-binding proteins, such as EF-hand superfamily proteins. Among the EF-hand superfamily proteins, allograft inflammatory factor-1 (AIF-1) and swiprosin-1/EF-hand domain-containing protein 2 (EFhd2) are cytosolic actin-binding proteins. AIF-1 modulates the cytoskeleton and increases the migration of immune cells. EFhd2 is also a cytoskeletal protein implicated in immune cell activation and brain cell functions. EFhd1, a mitochondrial fraternal twin of EFhd2, mediates neuronal and pro-/pre-B cell differentiation and mitoflash activation. Although EFhd1 is important for maintaining mitochondrial morphology and energy synthesis, its mechanism of action remains unclear. Here, we report the crystal structure of the EFhd1 core domain comprising a C-terminus of a proline-rich region, two EF-hand domains, and a ligand mimic helix. Structural comparisons of EFhd1, EFhd2, and AIF-1 revealed similarities in their overall structures. In the structure of the EFhd1 core domain, two Zn2+ ions were observed at the interface of the crystal contact, suggesting the possibility of Zn2+-mediated multimerization. In addition, we found that EFhd1 has Ca2+-independent β-actin-binding and Ca2+-dependent β-actin-bundling activities. These findings suggest that EFhd1, an actin-binding and -bundling protein in the mitochondria, may contribute to the Ca2+-dependent regulation of mitochondrial morphology and energy synthesis.
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Affiliation(s)
- Sang A Mun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Jongseo Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Kyoung Ryoung Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea.,NuclixBio, Seoul, South Korea
| | - Youngjin Lee
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Infection and Immunity Research Laboratory, Metabolic Regulation Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea
| | - Jung Youn Kang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Taein Park
- Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Minwoo Jin
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Jihyeong Yang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea
| | - Soo Hyun Eom
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Steitz Center for Structural Biology, Gwangju Institute of Science and Technology, Gwangju, South Korea.,Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju, South Korea
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15
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García-González J, van Gelderen K. Bundling up the Role of the Actin Cytoskeleton in Primary Root Growth. Front Plant Sci 2021; 12:777119. [PMID: 34975959 PMCID: PMC8716943 DOI: 10.3389/fpls.2021.777119] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 11/11/2021] [Indexed: 05/19/2023]
Abstract
Primary root growth is required by the plant to anchor in the soil and reach out for nutrients and water, while dealing with obstacles. Efficient root elongation and bending depends upon the coordinated action of environmental sensing, signal transduction, and growth responses. The actin cytoskeleton is a highly plastic network that constitutes a point of integration for environmental stimuli and hormonal pathways. In this review, we present a detailed compilation highlighting the importance of the actin cytoskeleton during primary root growth and we describe how actin-binding proteins, plant hormones, and actin-disrupting drugs affect root growth and root actin. We also discuss the feedback loop between actin and root responses to light and gravity. Actin affects cell division and elongation through the control of its own organization. We remark upon the importance of longitudinally oriented actin bundles as a hallmark of cell elongation as well as the role of the actin cytoskeleton in protein trafficking and vacuolar reshaping during this process. The actin network is shaped by a plethora of actin-binding proteins; however, there is still a large gap in connecting the molecular function of these proteins with their developmental effects. Here, we summarize their function and known effects on primary root growth with a focus on their high level of specialization. Light and gravity are key factors that help us understand root growth directionality. The response of the root to gravity relies on hormonal, particularly auxin, homeostasis, and the actin cytoskeleton. Actin is necessary for the perception of the gravity stimulus via the repositioning of sedimenting statoliths, but it is also involved in mediating the growth response via the trafficking of auxin transporters and cell elongation. Furthermore, auxin and auxin analogs can affect the composition of the actin network, indicating a potential feedback loop. Light, in its turn, affects actin organization and hence, root growth, although its precise role remains largely unknown. Recently, fundamental studies with the latest techniques have given us more in-depth knowledge of the role and organization of actin in the coordination of root growth; however, there remains a lot to discover, especially in how actin organization helps cell shaping, and therefore root growth.
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Affiliation(s)
- Judith García-González
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Laboratory of Hormonal Regulations in Plants, Institute of Experimental Botany, Czech Academy of Sciences, Prague, Czechia
- *Correspondence: Judith García-González,
| | - Kasper van Gelderen
- Plant Ecophysiology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, Netherlands
- Kasper van Gelderen,
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16
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Strudwick XL, Cowin AJ. Multifunctional Roles of the Actin-Binding Protein Flightless I in Inflammation, Cancer and Wound Healing. Front Cell Dev Biol 2020; 8:603508. [PMID: 33330501 PMCID: PMC7732498 DOI: 10.3389/fcell.2020.603508] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 10/30/2020] [Indexed: 11/20/2022] Open
Abstract
Flightless I is an actin-binding member of the gelsolin family of actin-remodeling proteins that inhibits actin polymerization but does not possess actin severing ability. Flightless I functions as a regulator of many cellular processes including proliferation, differentiation, apoptosis, and migration all of which are important for many physiological processes including wound repair, cancer progression and inflammation. More than simply facilitating cytoskeletal rearrangements, Flightless I has other important roles in the regulation of gene transcription within the nucleus where it interacts with nuclear hormone receptors to modulate cellular activities. In conjunction with key binding partners Leucine rich repeat in the Flightless I interaction proteins (LRRFIP)1/2, Flightless I acts both synergistically and competitively to regulate a wide range of cellular signaling including interacting with two of the most important inflammatory pathways, the NLRP3 inflammasome and the MyD88-TLR4 pathways. In this review we outline the current knowledge about this important cytoskeletal protein and describe its many functions across a range of health conditions and pathologies. We provide perspectives for future development of Flightless I as a potential target for clinical translation and insights into potential therapeutic approaches to manipulate Flightless I functions.
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Affiliation(s)
- Xanthe L Strudwick
- Regenerative Medicine, Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
| | - Allison J Cowin
- Regenerative Medicine, Future Industries Institute, University of South Australia, Mawson Lakes, SA, Australia
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17
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Kakurina GV, Kolegova ЕS, Shashova ЕЕ, Velikaya VV, Startseva ZА, Cheremisina ОV, Kondakova IV, Choinzonov ЕL. Association of mRNA Expression Levels of LRP1 and Actin-Binding Proteins with the Development of Laryngeal and Laryngopharyngeal Squamous Cell Carcinoma. Bull Exp Biol Med 2020; 169:802-805. [PMID: 33108559 DOI: 10.1007/s10517-020-04983-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Indexed: 11/26/2022]
Abstract
We analyzed the association of the level of mRNA expression of the main endocytosis receptor LRP1 and actin-binding proteins (ezrin, profilin-1, cofilin-1, and adenylyl cyclase-associated protein 1) with the development and metastasis of laryngeal and laryngopharyngeal squamous cell carcinoma. The mRNA expression was evaluated in paired tissue samples using quantitative reverse transcription real-time PCR (RT-qPCR) and SYBR Green reagents. The study included 38 patients with stage T1-4N0-1M0 laryngeal and laryngopharyngeal squamous cell carcinoma and 10 patients with chronic hyperplastic laryngitis or grade II-III epithelial dysplasia. The expression of LRP1 in patients with laryngeal and laryngopharyngeal squamous cell carcinoma depended on the stage of the tumor process. Against the background of low expression of LRP1 mRNA, the relationship between cofilin 1 and profilin 1 expression became stronger (r=0.08; p=0.05) and a correlation between cofilin 1 and esrin expression (r=0.7; p=0.05) appeared. Studies on a larger patient cohort are required to make a definite conclusion on the role of LRP1 in the development of laryngeal and laryngopharyngeal squamous cell carcinoma.
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Affiliation(s)
- G V Kakurina
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia.
| | - Е S Kolegova
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Е Е Shashova
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - V V Velikaya
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Zh А Startseva
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - О V Cheremisina
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - I V Kondakova
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
| | - Е L Choinzonov
- Cancer Research Institute, Tomsk National Research Medical Center, Russian Academy of Sciences, Tomsk, Russia
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18
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Tuan NM, Lee CH. Role of Anillin in Tumour: From a Prognostic Biomarker to a Novel Target. Cancers (Basel) 2020; 12:E1600. [PMID: 32560530 PMCID: PMC7353083 DOI: 10.3390/cancers12061600] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 01/21/2023] Open
Abstract
Anillin (ANLN), an actin-binding protein, reportedly plays a vital role in cell proliferation and migration, particularly in cytokinesis. Although there have been findings pointing to a contribution of ANLN to the development of cancer, the association of ANLN to cancer remains not fully understood. Here, we gather evidence to determine the applicability of ANLN as a prognostic tool for some types of cancer, and the impact that ANLN has on the hallmarks of cancer. We searched academic repositories including PubMed and Google Scholar to find and review studies related to cancer and ANLN. The conclusion is that ANLN could be a potent target for cancer treatment, but the roles ANLN, other than in cytokinesis and its influence on tumour microenvironment remodeling in cancer development, must be further elucidated, and specific ANLN inhibitors should be found.
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Affiliation(s)
| | - Chang Hoon Lee
- College of Pharmacy, Dongguk University, Seoul 04620, Korea;
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19
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Chen PW, Billington N, Maron BY, Sload JA, Chinthalapudi K, Heissler SM. The BAR domain of the Arf GTPase-activating protein ASAP1 directly binds actin filaments. J Biol Chem 2020; 295:11303-11315. [PMID: 32444496 DOI: 10.1074/jbc.ra119.009903] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 05/13/2020] [Indexed: 12/11/2022] Open
Abstract
The Arf GTPase-activating protein (Arf GAP) with SH3 domain, ankyrin repeat and PH domain 1 (ASAP1) establishes a connection between the cell membrane and the cortical actin cytoskeleton. The formation, maintenance, and turnover of actin filaments and bundles in the actin cortex are important for cell adhesion, invasion, and migration. Here, using actin cosedimentation, polymerization, and depolymerization assays, along with total internal reflection fluorescence (TIRF), confocal, and EM analyses, we show that the N-terminal N-BAR domain of ASAP1 directly binds to F-actin. We found that ASAP1 homodimerization aligns F-actin in predominantly unipolar bundles and stabilizes them against depolymerization. Furthermore, the ASAP1 N-BAR domain moderately reduced the spontaneous polymerization of G-actin. The overexpression of the ASAP1 BAR-PH tandem domain in fibroblasts induced the formation of actin-filled projections more effectively than did full-length ASAP1. An ASAP1 construct that lacked the N-BAR domain failed to induce cellular projections. Our results suggest that ASAP1 regulates the dynamics and the formation of higher-order actin structures, possibly through direct binding to F-actin via its N-BAR domain. We propose that ASAP1 is a hub protein for dynamic protein-protein interactions in mechanosensitive structures, such as focal adhesions, invadopodia, and podosomes, that are directly implicated in oncogenic events. The effect of ASAP1 on actin dynamics puts a spotlight on its function as a central signaling molecule that regulates the dynamics of the actin cytoskeleton by transmitting signals from the plasma membrane.
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Affiliation(s)
- Pei-Wen Chen
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Neil Billington
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
| | - Ben Y Maron
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Jeffrey A Sload
- Department of Biology, Williams College, Williamstown, Massachusetts, USA
| | - Krishna Chinthalapudi
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
| | - Sarah M Heissler
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA
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20
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Tokuraku K, Kuragano M, Uyeda TQP. Long-Range and Directional Allostery of Actin Filaments Plays Important Roles in Various Cellular Activities. Int J Mol Sci 2020; 21:E3209. [PMID: 32370032 DOI: 10.3390/ijms21093209] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 12/18/2022] Open
Abstract
A wide variety of uniquely localized actin-binding proteins (ABPs) are involved in various cellular activities, such as cytokinesis, migration, adhesion, morphogenesis, and intracellular transport. In a micrometer-scale space such as the inside of cells, protein molecules diffuse throughout the cell interior within seconds. In this condition, how can ABPs selectively bind to particular actin filaments when there is an abundance of actin filaments in the cytoplasm? In recent years, several ABPs have been reported to induce cooperative conformational changes to actin filaments allowing structural changes to propagate along the filament cables uni- or bidirectionally, thereby regulating the subsequent binding of ABPs. Such propagation of ABP-induced cooperative conformational changes in actin filaments may be advantageous for the elaborate regulation of cellular activities driven by actin-based machineries in the intracellular space, which is dominated by diffusion. In this review, we focus on long-range allosteric regulation driven by cooperative conformational changes of actin filaments that are evoked by binding of ABPs, and discuss roles of allostery of actin filaments in narrow intracellular spaces.
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21
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Nakai N, Sato K, Tani T, Saito K, Sato F, Terada S. Genetically encoded orientation probes for F-actin for fluorescence polarization microscopy. Microscopy (Oxf) 2020; 68:359-368. [PMID: 31264686 DOI: 10.1093/jmicro/dfz022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
Fluorescence polarization microscopy, which can visualize both position and orientation of fluorescent molecules, is useful for analyzing architectural dynamics of proteins in vivo, especially that of cytoskeletal proteins such as actin. Fluorescent phalloidin conjugates and SiR-actin can be used as F-actin orientation probes for fluorescence polarization microscopy, but a lack of appropriate methods for their introduction to living specimens especially to tissues, embryos, and whole animals hampers their applications to image the orientation of F-actin. To solve this problem, we have developed genetically encoded F-actin orientation probes for fluorescence polarization microscopy. We rigidly connected circular permutated green fluorescent protein (GFP) to the N-terminal α-helix of actin-binding protein Lifeact or utrophin calponin homology domain (UtrCH), and normal mEGFP to the C-terminal α-helix of UtrCH. After evaluation of ensemble and single particle fluorescence polarization with the instantaneous FluoPolScope, one of the constructs turned out to be suitable for practical usage in live cell imaging. Our new, genetically encoded F-actin orientation probe, which has a similar property of an F-actin probe to conventional GFP-UtrCH, is expected to report the 3D architecture of the actin cytoskeleton with fluorescence polarization microscopy, paving the way for both the single molecular orientation imaging in cultured cells and the sub-optical resolution architectural analysis of F-actin networks analysis of F-actin in various living systems.
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Affiliation(s)
- Nori Nakai
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Keisuke Sato
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Tomomi Tani
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Kenta Saito
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Fumiya Sato
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Sumio Terada
- Department of Neuroanatomy and Cellular Neurobiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
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22
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Chen DY, Husain M. Caspase-Mediated Cleavage of Human Cortactin during Influenza A Virus Infection Occurs in Its Actin-Binding Domains and Is Associated with Released Virus Titres. Viruses 2020; 12:v12010087. [PMID: 31940955 PMCID: PMC7019683 DOI: 10.3390/v12010087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/17/2022] Open
Abstract
Influenza A virus (IAV) exploits host factors to multiply and cause disease. An in-depth knowledge of this interaction of IAV with the host will aid the development of anti-IAV intervention strategies. Previously, we demonstrated that host cortactin, an actin filament-binding protein promotes IAV infection, but undergoes degradation via a lysosome-associated apoptotic pathway during the late stages of IAV infection. Next, we wanted to further understand the mechanisms and significance of this phenomenon. By using the RNA interference screens and site-directed mutagenesis followed by western blotting, we found that lysosome protease, cathepsin C is involved in cortactin degradation in human cells infected with IAV. Furthermore, executioner apoptotic caspase, caspase-3 not caspase-6 or caspase-7 is involved in cortactin degradation during IAV infection, and caspase-3 cleavage site is located in the first actin-binding repeat of cortactin polypeptide. Finally, when expressed ectopically, the cleavage-resistant cortactin mutants decreased the amount of IAV progeny released from infected cells that was enhanced by the cleavage-sensitive cortactin wild type. These data strengthen the hypothesis proposed earlier that host cortactin plays an inhibitory role during the late stages of IAV infection, and IAV is facilitating its degradation to undermine such function.
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Affiliation(s)
| | - Matloob Husain
- Correspondence: ; Tel.: +64-3-470-3420; Fax: +64-3-479-8540
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23
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Tsukuda S, Tamura A, Matsumoto K, Fujita Y, Nakata S, Kaneko T, Nakayama A, Nakagawa H, Terasaki AG. In Vitro Differentiation of Chicken Astrocytes: Growth, Morphology, and Protein Expression of Astrocytes in Primary Cultures. Zoolog Sci 2020; 36:458-467. [PMID: 31833316 DOI: 10.2108/zs180102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 06/19/2019] [Indexed: 11/17/2022]
Abstract
Astrocytes regulate synaptic transmission in the central nervous system. Astrocytes in vivo have "stems" that express glial fibrillary acidic protein (GFAP), intermediate filaments, and peripheral astrocyte processes (PAPs), which contain actin-rich cytoskeletal structures. At the PAPs, the perisynaptic glia contacts and enwraps synapses, and modulates glia-neuronal communication. Cultured astrocytes have been an invaluable tool for studying roles of astrocytes; however, the morphology of mammalian primary astrocytes cultured in conventional medium containing fetal bovine serum (FBS) was similar to that of fibroblasts, and many culture conditions have been developed to generate stellate astrocytes observed in vivo. Avian astrocytes have been prepared from embryonic chick forebrain and maintained at a high cell density in conventional FBS-containing medium as mammalian astrocytes, thus the morphological analysis of chicken astrocytes has not yet been performed. In the present study, we report that the morphology of astrocytes freshly harvested from the forebrain of a chicken embryo in serum-free Neurobasal medium with B-27 supplement and basic fibroblast growth factor (bFGF) is similar to that of the astrocyte morphology in vivo. We also find that astrocytes in this medium express similar levels of GFAP and two actin-binding proteins as astrocytes in conventional FBS-containing medium, although they have different morphologies. Furthermore, we confirmed that cryopreserved astrocytes differentiate faster than freshly harvested astrocytes.
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Affiliation(s)
- Satoko Tsukuda
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Akiko Tamura
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Kei Matsumoto
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Yuki Fujita
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Shihoko Nakata
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Tatsuroh Kaneko
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Ayako Nakayama
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan
| | - Hiroyuki Nakagawa
- Division of Biology, Faculty of Science, Fukuoka University, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
| | - Asako G Terasaki
- Department of Biology, Graduate School of Science, Chiba University, Yayoicho, Inage-ku, Chiba 263-8522, Japan,
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24
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Ozeki M, Aini W, Miyagawa-Hayashino A, Tamaki K. Prevention of Cell Growth by Suppression of Villin Expression in Lithocholic Acid-Stimulated HepG2 Cells. J Histochem Cytochem 2018; 67:129-141. [PMID: 30303767 DOI: 10.1369/0022155418804507] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Cholestasis is a condition wherein bile flow is interrupted and lithocholic acid is known to play a key role in causing severe liver injury. In this study, we performed in-depth analysis of the morphological changes in bile canaliculi and the biological role of villin in cholestasis using lithocholic acid-stimulated HepG2 human hepatocarcinoma cells. We confirmed disruption of the bile canaliculi in liver sections from a liver allograft patient with cholestasis. Lithocholic acid caused strong cytotoxicity in HepG2 cells, which was associated with abnormal morphology. Lithocholic acid reduced villin expression, which recovered in the presence of nuclear receptor agonists. Furthermore, villin mRNA expression increased following small interfering RNA (siRNA)-mediated knockdown of the nuclear farnesoid X receptor and pregnane X receptor. Villin knockdown using siRNA caused cell growth arrest in HepG2 cells. The effect of villin-knockdown on whole-genome expression in HepG2 cells was analyzed by DNA microarray. Our data suggest that lithocholic acid caused cell growth arrest by suppressing villin expression via farnesoid X receptor and pregnane X receptor in HepG2 cells.
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Affiliation(s)
- Munetaka Ozeki
- Department of Forensic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Wulamujiang Aini
- Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.,Experimental and Clinical Research Center, Diabetes and Obesity Research Laboratory, Kocaeli University, Izmit, Turkey
| | - Aya Miyagawa-Hayashino
- Department of Diagnostic Pathology, Kyoto University Hospital, Kyoto, Japan.,Pathology and diagnostics, Kansai Medical University Hospital, Osaka, Japan
| | - Keiji Tamaki
- Department of Forensic Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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25
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Jo S, Kim HR, Mun Y, Jun CD. Transgelin-2 in immunity: Its implication in cell therapy. J Leukoc Biol 2018; 104:903-910. [PMID: 29749649 DOI: 10.1002/jlb.mr1117-470r] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/02/2018] [Accepted: 04/03/2018] [Indexed: 12/31/2022] Open
Abstract
Transgelin-2 is a small 22-kDa actin-binding protein implicated in actin dynamics, which stabilizes actin structures and participates in actin-associated signaling pathways. Much curiosity regarding transgelin-2 has centered around its dysregulation in tumor development and associated diseases. However, recent studies have shed new light on the functions of transgelin-2, the only transgelin family member present in leukocytes, in the context of various immune responses. In this review, we outlined the biochemical properties of transgelin-2 and its physiological functions in T cells, B cells, and macrophages. Transgelin-2 regulates T cell activation by stabilizing the actin cytoskeleton at the immunological synapse. Transgelin-2 in B cells also participates in the stabilization of T cell-B cell conjugates. While transgelin-2 is expressed at trace levels in macrophages, its expression is highly upregulated upon lipopolysaccharide stimulation and plays an essential role in macrophage phagocytosis. Since transgelin-2 increases T cell adhesion to target cells via boosting the "inside-out" costimulatory activation of leukocyte function-associated antigen 1, transgelin-2 could be a suitable candidate to potentiate the antitumor response of cytotoxic T cells by compensating for the lack of costimulation in tumor microenvironment. We discussed the feasibility of using native or engineered transgelin-2 as a synergistic molecule in cell-based immunotherapies, without inducing off-target disturbance in actin dynamics in other cells.
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Affiliation(s)
- Suin Jo
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Hye-Ran Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - YeVin Mun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Chang-Duk Jun
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Immune Synapse and Cell Therapy Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
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26
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Abstract
Nuclear actin-binding proteins (ABPs) perform distinguishable functions compared with their cytoplasmic counterparts in extensive activities of living cells. In addition to the ability to regulate actin cytoskeleton dynamics, nuclear ABPs are associated with multiple nuclear biological processes, including chromatin remodeling, gene transcriptional regulation, DNA damage response, nucleocytoplasmic trafficking and nuclear structure maintenance. The nuclear translocation of ABPs is affected by numerous intracellular or extracellular stimuli, which may lead to developmental malformation, tumor initiation, tumor progression and metastasis. Abnormal expression of certain ABPs have been reported in different types of cancer. This review focuses on the newly identified roles of nuclear ABPs in the pathological processes associated with cancer.
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Affiliation(s)
- Xinyi Yang
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China
| | - Ying Lin
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510120, P.R. China
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27
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Abstract
Actin is a highly abundant protein in eukaryotic cells and dynamically changes its polymerized states with the help of actin-binding proteins. Its critical function as a constituent of cytoskeleton has been well-documented. Growing evidence demonstrates that actin is also present in nuclei, referred to as nuclear actin, and is involved in a number of nuclear processes, including transcriptional regulation and chromatin remodeling. The contribution of nuclear actin to transcriptional regulation can be explained by its direct interaction with transcription machineries and chromatin remodeling factors and by controlling the activities of transcription factors. In both cases, polymerized states of nuclear actin affect the transcriptional outcome. Nuclear actin also plays an important role in activating strongly silenced genes in somatic cells for transcriptional reprogramming. When these nuclear functions of actin are considered, it is plausible to speculate that nuclear actin is also implicated in embryonic development, in which numerous genes need to be activated in a well-coordinated manner. In this review, we especially focus on nuclear actin's roles in transcriptional activation, reprogramming and development, including stem cell differentiation and we discuss how nuclear actin can be an important player in development and cell differentiation.
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Affiliation(s)
- Shinji Misu
- Laboratory of Molecular Developmental Biology, Faculty of Biology-Oriented Science and Technology, Kindai University Kinokawa-shi, Japan
| | - Marina Takebayashi
- Laboratory of Molecular Developmental Biology, Faculty of Biology-Oriented Science and Technology, Kindai University Kinokawa-shi, Japan
| | - Kei Miyamoto
- Laboratory of Molecular Developmental Biology, Faculty of Biology-Oriented Science and Technology, Kindai University Kinokawa-shi, Japan
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28
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MacDonald LC, O’Keefe S, Parnes MF, MacDonald H, Stretz L, Templer SJ, Wong EL, Berger BW. A Secreted Ankyrin-Repeat Protein from Clinical Stenotrophomonas maltophilia Isolates Disrupts Actin Cytoskeletal Structure. ACS Infect Dis 2016; 2:62-70. [PMID: 27622948 DOI: 10.1021/acsinfecdis.5b00103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Stenotrophomonas maltophilia is an emerging, multidrug-resistant pathogen of increasing importance for the immunocompromised, including cystic fibrosis patients. Despite its significance as an emerging pathogen, relatively little is known regarding the specific factors and mechanisms that contribute to its pathogenicity. We identify and characterize a putative ankyrin-repeat protein (Smlt3054) unique to clinical S. maltophilia isolates that binds F-actin in vitro and co-localizes with actin in transfected HEK293a cells. Smlt3054 is endogenously expressed and secreted from clinical S. maltophilia isolates, but not an environmental isolate (R551-3). The in vitro binding of Smlt3054 to F-actin resulted in a thickening of the filaments as observed by TEM. Ectopic expression of Smlt3054-GFP exhibits strong co-localization with F-actin, with distinct, retrograde F-actin waves specifically associated with Smlt3054 in individual cells as well as formation of dense, internal inclusions at the expense of retrograde F-actin waves. Collectively, our results point to an interaction between Smlt3054 and F-actin. Furthermore, as a potentially secreted protein unique to clinical S. maltophilia isolates, Smlt3054 may serve as a starting point for understanding the mechanisms by which S. maltophilia has become an emergent pathogen.
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Affiliation(s)
- Logan C. MacDonald
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Sean O’Keefe
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Mei-Fan Parnes
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Hanlon MacDonald
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Lindsey Stretz
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Suzanne J. Templer
- Division of Infectious Disease, Lehigh Valley Health Network, 1250 South Cedar Crest Boulevard, Suite 200, Allentown, Pennsylvania 18103, United States
| | - Emily L. Wong
- Division of Infectious Disease, Lehigh Valley Health Network, 1250 South Cedar Crest Boulevard, Suite 200, Allentown, Pennsylvania 18103, United States
| | - Bryan W. Berger
- Program in Bioengineering and Department
of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
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29
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Qu X, Jiang Y, Chang M, Liu X, Zhang R, Huang S. Organization and regulation of the actin cytoskeleton in the pollen tube. Front Plant Sci 2015; 5:786. [PMID: 25620974 PMCID: PMC4287052 DOI: 10.3389/fpls.2014.00786] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 12/17/2014] [Indexed: 05/18/2023]
Abstract
Proper organization of the actin cytoskeleton is crucial for pollen tube growth. However, the precise mechanisms by which the actin cytoskeleton regulates pollen tube growth remain to be further elucidated. The functions of the actin cytoskeleton are dictated by its spatial organization and dynamics. However, early observations of the distribution of actin filaments at the pollen tube apex were quite perplexing, resulting in decades of controversial debate. Fortunately, due to improvements in fixation regimens for staining actin filaments in fixed pollen tubes, as well as the adoption of appropriate markers for visualizing actin filaments in living pollen tubes, this issue has been resolved and has given rise to the consensus view of the spatial distribution of actin filaments throughout the entire pollen tube. Importantly, recent descriptions of the dynamics of individual actin filaments in the apical region have expanded our understanding of the function of actin in regulation of pollen tube growth. Furthermore, careful documentation of the function and mode of action of several actin-binding proteins expressed in pollen have provided novel insights into the regulation of actin spatial distribution and dynamics. In the current review, we summarize our understanding of the organization, dynamics, and regulation of the actin cytoskeleton in the pollen tube.
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Affiliation(s)
- Xiaolu Qu
- Center for Plant Biology, School of Life Sciences, Tsinghua UniversityBeijing, China
| | - Yuxiang Jiang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Ming Chang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Xiaonan Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Ruihui Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany – Chinese Academy of SciencesBeijing, China
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30
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Kullmann JA, Wickertsheim I, Minnerup L, Costell M, Friauf E, Rust MB. Profilin1 activity in cerebellar granule neurons is required for radial migration in vivo. Cell Adh Migr 2014; 9:247-53. [PMID: 25495756 DOI: 10.4161/19336918.2014.983804] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Neuron migration defects are an important aspect of human neuropathies. The underlying molecular mechanisms of such migration defects are largely unknown. Actin dynamics has been recognized as an important determinant of neuronal migration, and we recently found that the actin-binding protein profilin1 is relevant for radial migration of cerebellar granule neurons (CGN). As the exploited brain-specific mutants lacked profilin1 in both neurons and glial cells, it remained unknown whether profilin1 activity in CGN is relevant for CGN migration in vivo. To test this, we capitalized on a transgenic mouse line that expresses a tamoxifen-inducible Cre variant in CGN, but no other cerebellar cell type. In these profilin1 mutants, the cell density was elevated in the molecular layer, and ectopic CGN occurred. Moreover, 5-bromo-2'-deoxyuridine tracing experiments revealed impaired CGN radial migration. Hence, our data demonstrate the cell autonomous role of profilin1 activity in CGN for radial migration.
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Key Words
- BrdU+, BrdU-positive
- BrdU, 5-bromo-2′-deoxyuridine
- CGN, cerebellar granule neurons
- CaMKIV, Ca2+/calmodulin-dependent protein kinase IV
- EGL, external granule cell layer
- IGL, internal granule cell layer
- ML, molecular layer
- Math1-Cre, Math1-mediated Cre expression
- NeuN, neuron-specific nuclear protein
- P, postnatal day
- PI, propidium iodide.
- Pfn1, profilin1
- actin dynamics
- actin treadmilling
- actin-binding protein
- cerebellar cortex
- cerebellar development
- cerebellar granule neurons
- cerebellum
- neuronal migration
- profilin
- radial migration
- βGal+, βGal-positive
- βGal, β-galactosidase
- βGal−, βGal-negative
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Affiliation(s)
- Jan A Kullmann
- a Neurobiology/Neurophysiology Group ; University of Kaiserslautern ; Kaiserslautern , Germany
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31
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Li MW, Xiao X, Mruk DD, Lam YL, Lee WM, Lui WY, Bonanomi M, Silvestrini B, Cheng CY. Actin-binding protein drebrin E is involved in junction dynamics during spermatogenesis. Spermatogenesis 2014; 1:123-136. [PMID: 22319661 DOI: 10.4161/spmg.1.2.16393] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The actin-based cytoskeleton plays a critical role in the seminiferous epithelium during spermatogenesis by conferring cell shape, adhesion, structural support and cell polarity to both Sertoli and developing germ cells, which are essential for spermatogonial stem cell renewal, maintenance of the stem cell niche, cell cycle progression, mitosis, meiosis, spermiogenesis and spermiation. However, few functional studies are found in the literature, which explore the functional significance of actin dynamics in these events. This by and large is due to a lack of information on the proteins that regulate actin dynamics. Herein, we report drebrin E is an integrated component of the apical ectoplasmic specialization (apical ES) and the basal ES at the blood-testis barrier (BTB) in the seminiferous epithelium of the adult rat testis. Using immunohistochemistry and dual-labeled immunofluorescence analysis, drebrin E was found to display a stage-specific localization at the apical ES, as well as at the basal ES at the BTB during the seminiferous epithelial cycle of spermatogenesis. Drebrin E was first detected in stage V tubules at the basal ES with the highest expression at the BTB at stages V and VI, but it diminished considerably by stages VII and VIII and was almost non-detectable until stage IV. At the apical ES, drebrin E was also first detected at stage V, surrounding the entire head of the elongating spermatid, but by stage VI its localization had "shifted" to localize most intensely and almost exclusively to the concave side of the spermatid head. In stage VII tubules, drebrin E co-localized with actin, as well as with two other actin regulatory proteins Eps8 (epidermal growth factor receptor pathway substrate 8, an actin capping and bundling protein) and Arp3 (actin-related protein 3, a component of the Arp2/3 complex known to regulate actin nucleation and branching). The localization of drebrin E at the apical ES was compromised following treatment of rats with adjudin, which is known to exert its destructive effects primarily at the apical ES by inducing premature loss of elongating/elongated spermatids from the epithelium, mimicking "spermiation." Instead of being restricted to the concave side of spermatid heads, drebrin E was found to be mis-localized in the seminiferous epithelium of adjudin-treated rats; it was also present on the convex side of elongating spermatids, but these cells were mis-oriented so that their heads no longer pointed toward the basement membrane. The expression of drebrin E by Sertoli cells was also found to be modulated by TGFβ3 and TNFα. Since Arp3, but not Eps8, was found to bind drebrin E; and cytokines were also shown to affect the cellular distribution of drebrin E and enhance the interaction between drebrin E and Arp3, these findings illustrate that cytokines may regulate BTB dynamics during the epithelial cycle by recruiting drebrin E and Arp3 to the BTB microenvironment to induce changes in the configuration of actin filament bundles at the basal ES. In summary, these findings illustrate drebrin E is working in concert with Arp3 to regulate actin filament bundles at both the apical and the basal ES in the testis, conferring adhesion and cell polarity at both sites during spermatogenesis.
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Affiliation(s)
- Michelle Wm Li
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Xiang Xiao
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Dolores D Mruk
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Yee-Ling Lam
- Center for Biomedical Research; The Population Council; New York, NY USA
| | - Will M Lee
- School of Biological Sciences; The University of Hong Kong; Hong Kong, China
| | - Wing-Yee Lui
- School of Biological Sciences; The University of Hong Kong; Hong Kong, China
| | | | | | - C Yan Cheng
- Center for Biomedical Research; The Population Council; New York, NY USA
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32
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Kallio JP, Kursula I. Recombinant production, purification and crystallization of the Toxoplasma gondii coronin WD40 domain. Acta Crystallogr F Struct Biol Commun 2014; 70:517-21. [PMID: 24699753 PMCID: PMC3976077 DOI: 10.1107/s2053230x14005196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 03/06/2014] [Indexed: 11/10/2022] Open
Abstract
Toxoplasma gondii is one of the most widely spread parasitic organisms in the world. Together with other apicomplexan parasites, it utilizes a special actin-myosin motor for its cellular movement, called gliding motility. This actin-based process is regulated by a small set of actin-binding proteins, which in Apicomplexa comprises only 10-15 proteins, compared with >150 in higher eukaryotes. Coronin is a highly conserved regulator of the actin cytoskeleton, but its functions, especially in parasites, have remained enigmatic. Coronins consist of an N-terminal actin-binding β-propeller WD40 domain, followed by a conserved region, and a C-terminal coiled-coil domain implicated in oligomerization. Here, the WD40 domain and the conserved region of coronin from T. gondii were produced recombinantly and crystallized. A single-wavelength diffraction data set was collected to a resolution of 1.65 Å. The crystal belonged to the orthorhombic space group C2221, with unit-cell parameters a = 55.13, b = 82.51, c = 156.98 Å.
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Affiliation(s)
- Juha Pekka Kallio
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and German Electron Synchrotron (DESY), Notkestrasse 85, Building 25b, 22607 Hamburg, Germany
| | - Inari Kursula
- Centre for Structural Systems Biology, Helmholtz Centre for Infection Research and German Electron Synchrotron (DESY), Notkestrasse 85, Building 25b, 22607 Hamburg, Germany
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, PO Box 3000, 90014 Oulu, Finland
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Durst S, Hedde PN, Brochhausen L, Nick P, Nienhaus GU, Maisch J. Organization of perinuclear actin in live tobacco cells observed by PALM with optical sectioning. J Plant Physiol 2014; 171:97-108. [PMID: 24331424 DOI: 10.1016/j.jplph.2013.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 10/20/2013] [Indexed: 05/21/2023]
Abstract
Actin performs a wide variety of different tasks. This functional diversity may be accomplished either by the formation of different isotypes or by suitable protein decoration that regulates structure and dynamics of actin filaments. To probe for such a potential differential decoration, the actin-binding peptide Lifeact was fused to different photoactivatable fluorescent proteins. These fusions were stably expressed in Nicotiana tabacum L. cv. Bright Yellow 2 cells to follow dynamic reorganization of the actin cytoskeleton during the cell cycle. The Lifeact-monomeric variant of IrisFP fusion protein was observed to indiscriminately label both, central and cortical, actin filaments, whereas the tetrameric Lifeact-photoswitchable red fluorescent protein fusion construct selectively labeled only a specific perinuclear sub-population of actin. By using photoactivated localization microscopy, we acquired super-resolution images with optical sectioning to obtain a 3D model of perinuclear actin. This novel approach revealed that the perinuclear actin basket wraps around the nuclear envelope in a lamellar fashion and repartitions toward the leading edge of the migrating nucleus. Based on these data, we suggest that actin that forms the perinuclear basket differs from other actin assemblies by a reduced decoration with actin binding proteins, which is consistent with the differential decoration model.
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Affiliation(s)
- Steffen Durst
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 2, D-76131 Karlsruhe, Germany
| | - Per Niklas Hedde
- Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe, Germany
| | - Linda Brochhausen
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 2, D-76131 Karlsruhe, Germany
| | - Peter Nick
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 2, D-76131 Karlsruhe, Germany
| | - Gerd Ulrich Nienhaus
- Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, D-76131 Karlsruhe, Germany; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jan Maisch
- Botanical Institute, Molecular Cell Biology, Karlsruhe Institute of Technology (KIT), Kaiserstraße 2, D-76131 Karlsruhe, Germany.
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Lemieux MG, Janzen D, Hwang R, Roldan J, Jarchum I, Knecht DA. Visualization of the actin cytoskeleton: different F-actin-binding probes tell different stories. Cytoskeleton (Hoboken) 2013; 71:157-69. [PMID: 24347465 DOI: 10.1002/cm.21160] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 10/31/2013] [Accepted: 12/10/2013] [Indexed: 02/06/2023]
Abstract
The actin cytoskeleton is necessary for cell viability and plays crucial roles in cell motility, endocytosis, growth, and cytokinesis. Hence visualization of dynamic changes in F-actin distribution in vivo is of central importance in cell biology. This has been accomplished by the development of fluorescent protein fusions to actin itself or to various actin-binding proteins, actin cross-linking proteins, and their respective actin-binding domains (ABDs). Although these protein fusions have been shown to bind to F-actin in vivo, we show that the fluorescent protein used for visualization changes the subset of F-actin labeled by an F-actin ABD probe. Further, different amino acid linkers between the fluorescent protein and ABD induced a similar change in localization. Although different linkers and fluorescent proteins can alter the subset of actin bound by a particular ABD, in most cases, the fusion protein did not label all of a cell's F-actin all of the time. Even LimEΔcoil and GFP-actin, which have been used extensively for cytoskeletal visualization, were highly variable in the subsets of actin that they labeled. Lifeact, conversely, clearly labeled cortical F-actin as well as F-actin in the anterior pseudopods of motile cells and in macropinocytotic cups. We conclude that Lifeact most accurately labels F-actin and is the best currently available probe for visualization of dynamic changes in F-actin networks.
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Affiliation(s)
- Michael G Lemieux
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, 06269
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Beck MR, Dixon RDS, Goicoechea SM, Murphy GS, Brungardt JG, Beam MT, Srinath P, Patel J, Mohiuddin J, Otey CA, Campbell SL. Structure and function of palladin's actin binding domain. J Mol Biol 2013; 425:3325-37. [PMID: 23806659 DOI: 10.1016/j.jmb.2013.06.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 06/03/2013] [Accepted: 06/11/2013] [Indexed: 11/28/2022]
Abstract
Here, we report the NMR structure of the actin-binding domain contained in the cell adhesion protein palladin. Previously, we demonstrated that one of the immunoglobulin domains of palladin (Ig3) is both necessary and sufficient for direct filamentous actin binding in vitro. In this study, we identify two basic patches on opposite faces of Ig3 that are critical for actin binding and cross-linking. Sedimentation equilibrium assays indicate that the Ig3 domain of palladin does not self-associate. These combined data are consistent with an actin cross-linking mechanism that involves concurrent attachment of two actin filaments by a single palladin molecule by an electrostatic mechanism. Palladin mutations that disrupt actin binding show altered cellular distributions and morphology of actin in cells, revealing a functional requirement for the interaction between palladin and actin in vivo.
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Affiliation(s)
- Moriah R Beck
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, 120 Mason Farm Road, Chapel Hill, NC 27599, USA.
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Li J, Pleskot R, Henty-Ridilla JL, Blanchoin L, Potocký M, Staiger CJ. Arabidopsis capping protein senses cellular phosphatidic acid levels and transduces these into changes in actin cytoskeleton dynamics. Plant Signal Behav 2012; 7:1727-1730. [PMID: 23072985 PMCID: PMC3578921 DOI: 10.4161/psb.22472] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Plants respond rapidly and precisely to a broad spectrum of developmental, biotic and abiotic cues. In many instances, signaling cascades involved in transducing this information result in changes to the cellular architecture and cytoskeletal rearrangements. Based originally on paradigms for animal cell signaling, phospholipids have received increased scrutiny as key intermediates for transmitting information to the actin cytoskeleton. Significantly, a wealth of biochemical data for plant actin-binding proteins (ABPs) demonstrates that many of these interact with phosphoinositide lipids in vitro. Moreover, phosphatidic acid (PA) has been identified not only as an abundant structural lipid in plants, but also as an intermediary in developmental and stress signaling pathways that lead to altered actin organization. Several years ago, the heterodimeric capping protein (CP) from Arabidopsis was demonstrated to bind PA and is negatively regulated by this lipid in vitro. Whether this form of regulation occurs in cells, however, remained a mystery. A new study, that combines live-cell imaging of cytoskeletal dynamics with reverse-genetic analyses in Arabidopsis, provides compelling new evidence that CP is inhibited from binding filament ends in the presence of PA in vivo. This allows rapid actin polymerization and increases in filament abundance following stimulation and could be one key factor in the physiological responses of plant cells to environmental stimuli.
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Affiliation(s)
- Jiejie Li
- Department of Biological Sciences; Purdue University; West Lafayette, IN USA
| | - Roman Pleskot
- Institute of Experimental Botany v.v.i.; Academy of Sciences of the Czech Republic; Prague, Czech Republic
| | | | - Laurent Blanchoin
- Institut de Recherches en Technologie et Sciences pour le Vivant; Laboratoire de Physiologie Cellulaire and Végétale; Commissariat á l’Energie Atomique/Centre National de la Recherche Scientifique/Institut National de la Recherche; Agronomique/Université Joseph Fourier; Grenoble, France
| | - Martin Potocký
- Institute of Experimental Botany v.v.i.; Academy of Sciences of the Czech Republic; Prague, Czech Republic
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Chiyomaru T, Tatarano S, Kawakami K, Enokida H, Yoshino H, Nohata N, Fuse M, Seki N, Nakagawa M. SWAP70, actin-binding protein, function as an oncogene targeting tumor-suppressive miR-145 in prostate cancer. Prostate 2011; 71:1559-67. [PMID: 21360565 DOI: 10.1002/pros.21372] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 02/07/2011] [Indexed: 01/02/2023]
Abstract
BACKGROUND MiR-145 is down-regulated in various human cancers. We previously demonstrated that some actin-binding proteins were targeted by several microRNAs (miRNAs), including miR-145, in bladder and prostate cancer (CaP). The aim of this study is to determine a novel oncogenic gene targeted by miR-145 by focusing on actin-binding proteins in CaP. METHODS We focused on the SWAP switching B-cell complex 70 kDa subunit (SWAP70), which is an F-actin binding protein involved in activating B-cell transformation. A luciferase reporter assay was used to identify the actual binding sites between miR-145 and SWAP70 mRNA. Cell viability was evaluated by cell proliferation, wound healing, and matrigel invasion assays in si-SWAP70 transfectants. A total of 75 clinical prostate specimens were subjected to immunohistochemistry of SWAP70. RESULTS Molecular target searches of this miRNA and the luciferase reporter assay showed that SWAP70 was directly regulated by miR-145. Silencing of SWAP70 studies demonstrated significant inhibitions of cell migration and invasion in CaP cell lines. The SWAP70 positive-staining was significantly higher in percentage in the CaP than in benign prostate hyperplasia tissue. CONCLUSIONS Down-regulation of miR-145 was a frequent event in CaP, and it may have a tumor suppressive function. SWAP70 may be a target of miR-145, and it might have a potential oncogenic function. The novel molecular networks though which miR-145 acts, may provide new insights into the underlying molecular mechanisms of CaP.
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Affiliation(s)
- Takeshi Chiyomaru
- Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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Yamashiro S, Speicher KD, Speicher DW, Fowler VM. Mammalian tropomodulins nucleate actin polymerization via their actin monomer binding and filament pointed end-capping activities. J Biol Chem 2010; 285:33265-33280. [PMID: 20650902 PMCID: PMC2963411 DOI: 10.1074/jbc.m110.144873] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/18/2010] [Indexed: 01/10/2023] Open
Abstract
Many actin-binding proteins have been shown to possess multiple activities to regulate filament dynamics. Tropomodulins (Tmod1-4) are a conserved family of actin filament pointed end-capping proteins. Our previous work has demonstrated that Tmod3 binds to monomeric actin in addition to capping pointed ends. Here, we show a novel actin-nucleating activity in mammalian Tmods. Comparison of Tmod isoforms revealed that Tmod1-3 but not Tmod4 nucleate actin filament assembly. All Tmods bind to monomeric actin, and Tmod3 forms a 1:1 complex with actin. By truncation and mutagenesis studies, we demonstrated that the second α-helix in the N-terminal domain of Tmod3 is essential for actin monomer binding. Chemical cross-linking and LC-MS/MS further indicated that residues in this second α-helix interact with actin subdomain 2, whereas Tmod3 N-terminal domain peptides distal to this α-helix interact with actin subdomain 1. Mutagenesis of Leu-73 to Asp, which disrupts the second α-helix of Tmod3, decreases both its actin monomer-binding and -nucleating activities. On the other hand, point mutations of residues in the C-terminal leucine-rich repeat domain of Tmod3 (Lys-317 in the fifth leucine-rich repeat β-sheet and Lys-344 or Arg-345/Arg-346 in the C-terminal α6-helix) significantly reduced pointed end-capping and nucleation without altering actin monomer binding. Taken together, our data indicate that Tmod3 binds actin monomers over an extended interface and that nucleating activity depends on actin monomer binding and pointed end-capping activities, contributed by N- and C-terminal domains of Tmod3, respectively. Tmod3 nucleation of actin assembly may regulate the cytoskeleton in dynamic cellular contexts.
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Affiliation(s)
- Sawako Yamashiro
- From the Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037.
| | - Kaye D Speicher
- Center for Systems and Computational Biology, The Wistar Institute, Philadelphia, Pennsylvania 19104
| | - David W Speicher
- Center for Systems and Computational Biology, The Wistar Institute, Philadelphia, Pennsylvania 19104
| | - Velia M Fowler
- From the Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037.
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Abstract
The dynamic remolding of the actin cytoskeleton is a critical part of most cellular activities, and malfunction of cytoskeletal proteins results in various human diseases. The transition between two forms of actin, monomeric or G-actin and filamentous or F-actin, is tightly regulated in time and space by a large number of signaling, scaffolding and actin-binding proteins (ABPs). New ABPs are constantly being discovered in the post-genomic era. Most of these proteins are modular, integrating actin binding, protein-protein interaction, membrane-binding, and signaling domains. In response to extracellular signals, often mediated by Rho family GTPases, ABPs control different steps of actin cytoskeleton assembly, including filament nucleation, elongation, severing, capping, and depolymerization. This review summarizes structure-function relationships among ABPs in the regulation of actin cytoskeleton assembly.
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Affiliation(s)
- Sung Haeng Lee
- Chosun University School of Medicine, Department of Cellular and Molecular Medicine, Gwangju 501-759, Korea.
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40
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Lee SH, Weins A, Hayes DB, Pollak MR, Dominguez R. Crystal structure of the actin-binding domain of alpha-actinin-4 Lys255Glu mutant implicated in focal segmental glomerulosclerosis. J Mol Biol 2008; 376:317-24. [PMID: 18164029 PMCID: PMC2255586 DOI: 10.1016/j.jmb.2007.11.084] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2007] [Revised: 11/22/2007] [Accepted: 11/28/2007] [Indexed: 11/28/2022]
Abstract
Mutations in alpha-actinin-4 have been linked to familial focal segmental glomerulosclerosis (FSGS), a common renal disorder in humans, and produce an apparent increase in the actin-binding affinity of alpha-actinin-4 in vitro. One of the mutations, in particular, Lys255Glu, falls in the middle of the actin-binding interface of the actin-binding domain (ABD). The ABD consists of tandem calponin homology (CH) domains (CH1 and CH2). The crystal structures of most ABDs display a compact conformation, characterized by extensive inter-CH interactions. However, the conformation of F-actin-bound ABDs is unsettled. Some electron microscopy studies find that the compact conformation is preserved upon binding to F-actin, whereas other studies suggest that the CHs separate and the ABD becomes extended. The Lys255Glu mutation in CH2 is significant in this regard since it removes a crucial inter-CH interaction with Trp147 of CH1, thought to stabilize the compact conformation. Together, the increased actin-binding affinity and the removal of this important inter-CH contact suggested that the Lys255Glu mutation might facilitate the transition toward the open ABD conformation proposed by some of the electron microscopy studies. However, the crystal structure of the ABD of alpha-actinin-4 Lys255Glu mutant described here displays the canonical compact conformation. Furthermore, the sedimentation coefficients by analytical ultracentrifugation of wild-type and FSGS mutant ABDs (Lys255Glu, Ser262Pro, and Thr259Ile) are nearly identical (2.50+/-0.03 S) and are in good agreement with the theoretical value calculated from the crystal structure (2.382 S), implying that the compact conformation is retained in solution. The absence of a structural change suggests that the compact ABD conformation observed in the majority of the structures is highly stable and is preserved in solution, even in FSGS mutant ABDs.
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Affiliation(s)
- Sung Haeng Lee
- University of Pennsylvania School of Medicine, Department of Physiology, 3700 Hamilton Walk, Philadelphia, PA 19104−6085
| | - Astrid Weins
- Renal and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - David B. Hayes
- Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472
| | - Martin R. Pollak
- Renal and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Roberto Dominguez
- University of Pennsylvania School of Medicine, Department of Physiology, 3700 Hamilton Walk, Philadelphia, PA 19104−6085
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van Kesteren RE, Carter C, Dissel HMG, van Minnen J, Gouwenberg Y, Syed NI, Spencer GE, Smit AB. Local synthesis of actin-binding protein beta-thymosin regulates neurite outgrowth. J Neurosci 2006; 26:152-7. [PMID: 16399682 PMCID: PMC6674307 DOI: 10.1523/jneurosci.4164-05.2006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 11/07/2005] [Accepted: 11/07/2005] [Indexed: 11/21/2022] Open
Abstract
Local protein synthesis plays an essential role in the regulation of various aspects of axonal and dendritic function in adult neurons. At present, however, there is no direct evidence that local protein translation is functionally contributing to neuronal outgrowth. Here, we identified the mRNA encoding the actin-binding protein beta-thymosin as one of the most abundant transcripts in neurites of outgrowing neurons in culture. Beta-thymosin mRNA is not evenly distributed in neurites, but appears to accumulate at distinct sites such as turning points and growth cones. Using double-stranded RNA knockdown, we show that reducing beta-thymosin mRNA levels results in a significant increase in neurite outgrowth, both in neurites of intact cells and in isolated neurites. Together, our data demonstrate that local synthesis of beta-thymosin is functionally involved in regulating neuronal outgrowth.
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Affiliation(s)
- Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Research Institute Neurosciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.
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Vermeulen W, Vanhaesebrouck P, Van Troys M, Verschueren M, Fant F, Goethals M, Ampe C, Martins JC, Borremans FAM. Solution structures of the C-terminal headpiece subdomains of human villin and advillin, evaluation of headpiece F-actin-binding requirements. Protein Sci 2004; 13:1276-87. [PMID: 15096633 PMCID: PMC2286768 DOI: 10.1110/ps.03518104] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Revised: 02/12/2004] [Accepted: 02/14/2004] [Indexed: 10/26/2022]
Abstract
Headpiece (HP) is a 76-residue F-actin-binding module at the C terminus of many cytoskeletal proteins. Its 35-residue C-terminal subdomain is one of the smallest known motifs capable of autonomously adopting a stable, folded structure in the absence of any disulfide bridges, metal ligands, or unnatural amino acids. We report the three-dimensional solution structures of the C-terminal headpiece subdomains of human villin (HVcHP) and human advillin (HAcHP), determined by two-dimensional 1H-NMR. They represent the second and third structures of such C-terminal headpiece subdomains to be elucidated so far. A comparison with the structure of the chicken villin C-terminal subdomain reveals a high structural conservation. Both C-terminal subdomains bind specifically to F-actin. Mutagenesis is used to demonstrate the involvement of Trp 64 in the F-actin-binding surface. The latter residue is part of a conserved structural feature, in which the surface-exposed indole ring is stacked on the proline and lysine side chain embedded in a PXWK sequence motif. On the basis of the structural and mutational data concerning Trp 64 reported here, the results of a cysteine-scanning mutagenesis study of full headpiece, and a phage display mutational study of the 69-74 fragment, we propose a modification of the model, elaborated by Vardar and coworkers, for the binding of headpiece to F-actin.
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Affiliation(s)
- Wim Vermeulen
- NMR and Structure Analysis Unit, Department of Organic Chemistry, Faculty of Sciences, Ghent University, 9000 Ghent, Belgium
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Abstract
Paxillin is a focal adhesion adapter protein involved in the integration of growth factor- and adhesion-mediated signal transduction pathways. Paxillin LD motifs have been demonstrated to bind to several proteins associated with remodeling of the actin cytoskeleton including the focal adhesion kinase, vinculin, and a complex of proteins comprising p95PKL, PIX, and PAK (Turner, C.E., M. C. Brown, J.A. Perrotta, M.C. Riedy, S.N. Nikolopoulos, A.R. McDonald, S. Bagrodia, S. Thomas, and P.S. Leventhal. 1999. J. Cell Biol. 145:851-863). In this study, we report the cloning and initial characterization of a new paxillin LD motif-binding protein, actopaxin. Analysis of the deduced amino acid sequence of actopaxin reveals a 42-kD protein with two calponin homology domains and a paxillin-binding subdomain (PBS). Western blotting identifies actopaxin as a widely expressed protein. Actopaxin binds directly to both F-actin and paxillin LD1 and LD4 motifs. It exhibits robust focal adhesion localization in several cultured cell types but is not found along the length of the associated actin-rich stress fibers. Similar to paxillin, it is absent from actin-rich cell-cell adherens junctions. Also, actopaxin colocalizes with paxillin to rudimentary focal complexes at the leading edge of migrating cells. An actopaxin PBS mutant incapable of binding paxillin in vitro cannot target to focal adhesions when expressed in fibroblasts. In addition, ectopic expression of the PBS mutant and/or the COOH terminus of actopaxin in HeLa cells resulted in substantial reduction in adhesion to collagen. Together, these results suggest an important role for actopaxin in integrin-dependent remodeling of the actin cytoskeleton during cell motility and cell adhesion.
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Affiliation(s)
- Sotiris N. Nikolopoulos
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
| | - Christopher E. Turner
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, New York 13210
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Petrecca K, Miller DM, Shrier A. Localization and enhanced current density of the Kv4.2 potassium channel by interaction with the actin-binding protein filamin. J Neurosci 2000; 20:8736-44. [PMID: 11102480 PMCID: PMC6773047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
Kv4.2 potassium channels play a critical role in postsynaptic excitability. Immunocytochemical studies reveal a somatodendritic Kv4.2 expression pattern, with the channels concentrated mainly at dendritic spines. The molecular mechanism that underlies the localization of Kv4.2 to this subcellular region is unknown. We used the yeast two-hybrid system to identify the Kv4.2-associated proteins that are involved in channel localization. Here we demonstrate a direct interaction between Kv4.2 and the actin-binding protein, filamin. We show that Kv4.2 and filamin can be coimmunoprecipitated both in vitro and in brain and that Kv4.2 and filamin share an overlapping expression pattern in the cerebellum and cultured hippocampal neurons. To examine the functional consequences of this interaction, we expressed Kv4.2 in filamin(+) and filamin(-) cells and performed immunocytochemical and electrophysiological analyses. Our results indicate that Kv4.2 colocalizes with filamin at filopodial roots in filamin(+) cells but shows a nonspecific expression pattern in filamin(-) cells, with no localization to filopodial roots. Furthermore, the magnitude of whole-cell Kv4.2 current density is approximately 2.7-fold larger in filamin(+) cells as compared with these currents in filamin(-) cells. We propose that filamin may function as a scaffold protein in the postsynaptic density, mediating a direct link between Kv4.2 and the actin cytoskeleton, and that this interaction is essential for the generation of appropriate Kv4.2 current densities.
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Affiliation(s)
- K Petrecca
- Department of Physiology, McGill University, Montréal, Québec, Canada H3G 1Y6
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Ohtsuka T, Nakanishi H, Ikeda W, Satoh A, Momose Y, Nishioka H, Takai Y. Nexilin: a novel actin filament-binding protein localized at cell-matrix adherens junction. J Cell Biol 1998; 143:1227-38. [PMID: 9832551 PMCID: PMC2133087 DOI: 10.1083/jcb.143.5.1227] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/1998] [Revised: 09/21/1998] [Indexed: 01/27/2023] Open
Abstract
We isolated two novel actin filament (F-actin)-binding proteins from rat brain and rat 3Y1 fibroblast. They were splicing variants, and we named brain big one b-nexilin and fibroblast small one s-nexilin. b-Nexilin purified from rat brain was a protein of 656 amino acids (aa) with a calculated molecular weight of 78,392, whereas s-nexilin, encoded by the cDNA isolated from rat 3Y1 cells by the reverse transcriptase-PCR method, was a protein of 606 aa with a calculated molecular weight of 71,942. b-Nexilin had two F-actin- binding domains (ABDs) at the NH2-terminal and middle regions, whereas s-nexilin had one ABD at the middle region because 64 aa residues were deleted and 14 aa residues were inserted in the first NH2-terminal ABD of b-nexilin, and thereby the first ABD lost its activity. b- and s-nexilins bound along the sides of F-actin, but only b-nexilin showed F-actin cross-linking activity. b-Nexilin was mainly expressed in brain and testis, whereas s-nexilin was mainly expressed in testis, spleen, and fibroblasts, such as rat 3Y1 and mouse Swiss 3T3 cells, but neither b- nor s-nexilin was detected in liver, kidney, or cultured epithelial cells. An immunofluorescence microscopic study revealed that s-nexilin was colocalized with vinculin, talin, and paxillin at cell- matrix adherens junction (AJ) and focal contacts, but not at cell-cell AJ, in 3Y1 cells. Overexpressed b- and s-nexilins were localized at focal contacts but not at cell-cell AJ. These results indicate that nexilin is a novel F-actin-binding protein localized at cell-matrix AJ.
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Affiliation(s)
- T Ohtsuka
- Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565-0871, Japan
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Abstract
We have purified a protein from rabbit serum with a molecular weight of 90,000 that inhibits the polymerization of actin measured viscometrically and that we have named "brevin" (from the Latin breviare, to shorten). From the extent of purification, we estimate that this inhibitor constitutes 0.3% of the total protein in plasma and serum. Brevin is also present in sera from humans and rats. Almost all of the activity in blood is extracellular; only 1% is present in platelets or other cellular elements. Several lines of evidence indicate that brevin is the same protein as the factor described by Fagraeus and Norberg [Fagraeus, A. & Norberg, R. (1978) Curr. Top. Microbiol. Immunol. 82, 1-13] as an actin-depolymerizing factor (ADF). If ADF and brevin are identical, then "ADF" is an inappropriate name because we find that the protein shortens actin filaments without depolymerizing them. Thus, brevin causes little change in the critical concentration of monomeric actin, even though the inhibitor binds to monomeric actin complexed to DNase I-agarose. Binding of brevin to filaments was demonstrated by sedimenting the inhibitor with F-actin. From the amounts of actin and brevin sedimented, and from the lengths of filaments measured by electron microscopy, we calculated that the stoichiometry of binding is one brevin molecule per filament over a wide range of inhibitor concentrations. This stoichiometry suggests that brevin inhibits polymerization by binding at the end of elongating actin filaments, a mechanism similar to that proposed for several intracellular actin-binding proteins and for the cytochalasins. Its abundance suggests that brevin plays an important physiological role in serum, but one not directly concerned with intracellular motility. Therefore its relationship to cytoplasmic actin-binding proteins remains to be determined.
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