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van Zwam MC, Dhar A, Bosman W, van Straaten W, Weijers S, Seta E, Joosten B, van Haren J, Palani S, van den Dries K. IntAct: A nondisruptive internal tagging strategy to study the organization and function of actin isoforms. PLoS Biol 2024; 22:e3002551. [PMID: 38466773 PMCID: PMC10957077 DOI: 10.1371/journal.pbio.3002551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 03/21/2024] [Accepted: 02/16/2024] [Indexed: 03/13/2024] Open
Abstract
Mammals have 6 highly conserved actin isoforms with nonredundant biological functions. The molecular basis of isoform specificity, however, remains elusive due to a lack of tools. Here, we describe the development of IntAct, an internal tagging strategy to study actin isoforms in fixed and living cells. We identified a residue pair in β-actin that permits tag integration and used knock-in cell lines to demonstrate that IntAct β-actin expression and filament incorporation is indistinguishable from wild type. Furthermore, IntAct β-actin remains associated with common actin-binding proteins (ABPs) and can be targeted in living cells. We demonstrate the usability of IntAct for actin isoform investigations by showing that actin isoform-specific distribution is maintained in human cells. Lastly, we observed a variant-dependent incorporation of tagged actin variants into yeast actin patches, cables, and cytokinetic rings demonstrating cross species applicability. Together, our data indicate that IntAct is a versatile tool to study actin isoform localization, dynamics, and molecular interactions.
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Affiliation(s)
- Maxime C. van Zwam
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anubhav Dhar
- Department of Biochemistry, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Willem Bosman
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Wendy van Straaten
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Suzanne Weijers
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Emiel Seta
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ben Joosten
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Saravanan Palani
- Department of Biochemistry, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Koen van den Dries
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, the Netherlands
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Lacoste J, Haghighi M, Haider S, Lin ZY, Segal D, Reno C, Qian WW, Xiong X, Shafqat-Abbasi H, Ryder PV, Senft R, Cimini BA, Roth FP, Calderwood M, Hill D, Vidal M, Yi SS, Sahni N, Peng J, Gingras AC, Singh S, Carpenter AE, Taipale M. Pervasive mislocalization of pathogenic coding variants underlying human disorders. bioRxiv 2023:2023.09.05.556368. [PMID: 37732209 PMCID: PMC10508771 DOI: 10.1101/2023.09.05.556368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Widespread sequencing has yielded thousands of missense variants predicted or confirmed as disease-causing. This creates a new bottleneck: determining the functional impact of each variant - largely a painstaking, customized process undertaken one or a few genes or variants at a time. Here, we established a high-throughput imaging platform to assay the impact of coding variation on protein localization, evaluating 3,547 missense variants of over 1,000 genes and phenotypes. We discovered that mislocalization is a common consequence of coding variation, affecting about one-sixth of all pathogenic missense variants, all cellular compartments, and recessive and dominant disorders alike. Mislocalization is primarily driven by effects on protein stability and membrane insertion rather than disruptions of trafficking signals or specific interactions. Furthermore, mislocalization patterns help explain pleiotropy and disease severity and provide insights on variants of unknown significance. Our publicly available resource will likely accelerate the understanding of coding variation in human diseases.
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Affiliation(s)
- Jessica Lacoste
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
- These authors contributed equally
| | - Marzieh Haghighi
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
- These authors contributed equally
| | - Shahan Haider
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
| | - Dmitri Segal
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Chloe Reno
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | - Wesley Wei Qian
- Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Xueting Xiong
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
| | | | | | - Rebecca Senft
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | | | - Frederick P. Roth
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
- Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Calderwood
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - David Hill
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Marc Vidal
- Center for Cancer Systems Biology (CCSB), Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - S. Stephen Yi
- Livestrong Cancer Institutes, Department of Oncology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
- Oden Institute for Computational Engineering and Sciences (ICES), The University of Texas at Austin, Austin, TX, USA
- Department of Biomedical Engineering, Cockrell School of Engineering, The University of Texas at Austin, Austin, TX, USA
- Interdisciplinary Life Sciences Graduate Programs (ILSGP), College of Natural Sciences, The University of Texas at Austin, Austin, TX, USA
| | - Nidhi Sahni
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Quantitative and Computational Biosciences Program, Baylor College of Medicine, Houston, TX, USA
| | - Jian Peng
- Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Canada
| | | | | | - Mikko Taipale
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Canada
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Chen J, Kaw K, Lu H, Fagnant PM, Chattopadhyay A, Duan XY, Zhou Z, Ma S, Liu Z, Huang J, Kamm K, Stull JT, Kwartler CS, Trybus KM, Milewicz DM. Resistance of Acta2 R149C/+ mice to aortic disease is associated with defective release of mutant smooth muscle α-actin from the chaperonin-containing TCP1 folding complex. J Biol Chem 2021; 297:101228. [PMID: 34600884 PMCID: PMC8633019 DOI: 10.1016/j.jbc.2021.101228] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 04/22/2021] [Revised: 09/12/2021] [Accepted: 09/21/2021] [Indexed: 11/04/2022] Open
Abstract
Pathogenic variants of the gene for smooth muscle α-actin (ACTA2), which encodes smooth muscle (SM) α-actin, predispose to heritable thoracic aortic disease. The ACTA2 variant p.Arg149Cys (R149C) is the most common alteration; however, only 60% of carriers have a dissection or undergo repair of an aneurysm by 70 years of age. A mouse model of ACTA2 p.Arg149Cys was generated using CRISPR/Cas9 technology to determine the etiology of reduced penetrance. Acta2R149C/+ mice had significantly decreased aortic contraction compared with WT mice but did not form aortic aneurysms or dissections when followed to 24 months, even when hypertension was induced. In vitro motility assays found decreased interaction of mutant SM α-actin filaments with SM myosin. Polymerization studies using total internal reflection fluorescence microscopy showed enhanced nucleation of mutant SM α-actin by formin, which correlated with disorganized and reduced SM α-actin filaments in Acta2R149C/+ smooth muscle cells (SMCs). However, the most prominent molecular defect was the increased retention of mutant SM α-actin in the chaperonin-containing t-complex polypeptide folding complex, which was associated with reduced levels of mutant compared with WT SM α-actin in Acta2R149C/+ SMCs. These data indicate that Acta2R149C/+ mice do not develop thoracic aortic disease despite decreased contraction of aortic segments and disrupted SM α-actin filament formation and function in Acta2R149C/+ SMCs. Enhanced binding of mutant SM α-actin to chaperonin-containing t-complex polypeptide decreases the mutant actin versus WT monomer levels in Acta2R149C/+ SMCs, thus minimizing the effect of the mutation on SMC function and potentially preventing aortic disease in the Acta2R149C/+ mice.
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Affiliation(s)
- Jiyuan Chen
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Kaveeta Kaw
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Hailong Lu
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Patricia M Fagnant
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Abhijnan Chattopadhyay
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Xue Yan Duan
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Zhen Zhou
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Shuangtao Ma
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Zhenan Liu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jian Huang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kristine Kamm
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - James T Stull
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Callie S Kwartler
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA
| | - Kathleen M Trybus
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Dianna M Milewicz
- Division of Medical Genetic, Department of Internal Medicine, McGovern Medical School, University of Texas Health Science Center at Houston, Texas, USA.
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Malek N, Michrowska A, Mazurkiewicz E, Mrówczyńska E, Mackiewicz P, Mazur AJ. The origin of the expressed retrotransposed gene ACTBL2 and its influence on human melanoma cells' motility and focal adhesion formation. Sci Rep 2021; 11:3329. [PMID: 33558623 PMCID: PMC7870945 DOI: 10.1038/s41598-021-82074-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 10/16/2020] [Accepted: 01/08/2021] [Indexed: 01/30/2023] Open
Abstract
We have recently found that β-actin-like protein 2 (actbl2) forms complexes with gelsolin in human melanoma cells and can polymerize. Phylogenetic and bioinformatic analyses showed that actbl2 has a common origin with two non-muscle actins, which share a separate history from the muscle actins. The actin groups' divergence started at the beginning of vertebrate evolution, and actbl2 actins are characterized by the largest number of non-conserved amino acid substitutions of all actins. We also discovered that ACTBL2 is expressed at a very low level in several melanoma cell lines, but a small subset of cells exhibited a high ACTBL2 expression. We found that clones with knocked-out ACTBL2 (CR-ACTBL2) or overexpressing actbl2 (OE-ACTBL2) differ from control cells in the invasion, focal adhesion formation, and actin polymerization ratio, as well as in the formation of lamellipodia and stress fibers. Thus, we postulate that actbl2 is the seventh actin isoform and is essential for cell motility.
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Affiliation(s)
- Natalia Malek
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Aleksandra Michrowska
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Ewa Mazurkiewicz
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Ewa Mrówczyńska
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Paweł Mackiewicz
- Department of Bioinformatics and Genomics, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, Wroclaw, 50-383, Poland
| | - Antonina J Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, ul. Joliot-Curie 14a, 50-383, Wroclaw, Poland.
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Abstract
Actin is a widely expressed protein found in almost all eukaryotic cells. In humans, there are six different genes, which encode specific actin isoforms. Disease-causing mutations have been described for each of these, most of which are missense. Analysis of the position of the resulting mutated residues in the protein reveals mutational hotspots. Many of these occur in regions important for actin polymerization. We briefly discuss the challenges in characterizing the effects of these actin mutations, with a focus on cardiac actin mutations.
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Simiczyjew A, Mazur AJ, Dratkiewicz E, Nowak D. Involvement of β- and γ-actin isoforms in actin cytoskeleton organization and migration abilities of bleb-forming human colon cancer cells. PLoS One 2017; 12:e0173709. [PMID: 28333953 PMCID: PMC5363831 DOI: 10.1371/journal.pone.0173709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/15/2017] [Indexed: 12/13/2022] Open
Abstract
Amoeboid movement is characteristic for rounded cells, which do not form strong adhesion contacts with the ECM and use blebs as migratory protrusions. It is well known that actin is the main component of mature forms of these structures, but the exact role fulfilled by non-muscle actin isoforms β- and γ- in bleb formation and migration of these cells is still not fully understood. The aim of this study was to establish the role of β- and γ-actin in migration of bleb-forming cancer cells using isoform-specific antibodies and expression of fluorescently tagged actin isoforms. We observed, after staining with monoclonal antibodies, that both actins are present in these cells in the form of a cortical ring as well as in the area of blebs. Additionally, using simultaneous expression of differentially tagged β- and γ-actin in cells, we observed that the actin isoforms are present together in a single bleb. They were involved during bleb expansion as well as retraction. Also present in the area of these protrusions formed by both isoforms were the bleb markers–ezrin and myosin II. The overexpression of β- or γ-actin led to actin cytoskeletal rearrangement followed by the growth of migration and invasion abilities of examined human colon cancer cells, LS174T line. In summary these data prove that both actin isoforms have an impact on motility of bleb-forming cancer cells. Moreover, we conclude that monoclonal antibodies directed against actin isoforms in combination with the tagged actins are good tools to study their role in important biological processes.
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Affiliation(s)
- Aleksandra Simiczyjew
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, Poland
- * E-mail:
| | - Antonina Joanna Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, Poland
| | - Ewelina Dratkiewicz
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, Poland
| | - Dorota Nowak
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, Wroclaw, Poland
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Kratter IH, Zahed H, Lau A, Tsvetkov AS, Daub AC, Weiberth KF, Gu X, Saudou F, Humbert S, Yang XW, Osmand A, Steffan JS, Masliah E, Finkbeiner S. Serine 421 regulates mutant huntingtin toxicity and clearance in mice. J Clin Invest 2016; 126:3585-97. [PMID: 27525439 DOI: 10.1172/jci80339] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 06/30/2016] [Indexed: 01/17/2023] Open
Abstract
Huntington's disease (HD) is a progressive, adult-onset neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the N-terminal region of the protein huntingtin (HTT). There are no cures or disease-modifying therapies for HD. HTT has a highly conserved Akt phosphorylation site at serine 421, and prior work in HD models found that phosphorylation at S421 (S421-P) diminishes the toxicity of mutant HTT (mHTT) fragments in neuronal cultures. However, whether S421-P affects the toxicity of mHTT in vivo remains unknown. In this work, we used murine models to investigate the role of S421-P in HTT-induced neurodegeneration. Specifically, we mutated the human mHTT gene within a BAC to express either an aspartic acid or an alanine at position 421, mimicking tonic phosphorylation (mHTT-S421D mice) or preventing phosphorylation (mHTT-S421A mice), respectively. Mimicking HTT phosphorylation strongly ameliorated mHTT-induced behavioral dysfunction and striatal neurodegeneration, whereas neuronal dysfunction persisted when S421 phosphorylation was blocked. We found that S421 phosphorylation mitigates neurodegeneration by increasing proteasome-dependent turnover of mHTT and reducing the presence of a toxic mHTT conformer. These data indicate that S421 is a potent modifier of mHTT toxicity and offer in vivo validation for S421 as a therapeutic target in HD.
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Abstract
Actin is the central building block of the actin cytoskeleton, a highly regulated filamentous network enabling dynamic processes of cells and simultaneously providing structure. Mammals have six actin isoforms that are very conserved and thus share common functions. Tissue-specific expression in part underlies their differential roles, but actin isoforms also coexist in various cell types and tissues, suggesting specific functions and preferential interaction partners. Gene deletion models, antibody-based staining patterns, gene silencing effects, and the occurrence of isoform-specific mutations in certain diseases have provided clues for specificity on the subcellular level and its consequences on the organism level. Yet, the differential actin isoform functions are still far from understood in detail. Biochemical studies on the different isoforms in pure form are just emerging, and investigations in cells have to deal with a complex and regulated system, including compensatory actin isoform expression.
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Affiliation(s)
- Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium.
| | - Marleen Van Troys
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, A. Baertsoenkaai 3, 9000, Ghent, Belgium
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Simiczyjew A, Mazur AJ, Ampe C, Malicka-Błaszkiewicz M, van Troys M, Nowak D. Active invadopodia of mesenchymally migrating cancer cells contain both β and γ cytoplasmic actin isoforms. Exp Cell Res 2015; 339:206-19. [PMID: 26548725 DOI: 10.1016/j.yexcr.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 10/30/2015] [Accepted: 11/04/2015] [Indexed: 10/25/2022]
Abstract
Invadopodia are actin-rich protrusions formed by mesenchymally migrating cancer cells. They are mainly composed of actin, actin-associated proteins, integrins and proteins of signaling machineries. These protrusions display focalized proteolytic activity towards the extracellular matrix. It is well known that polymerized (F-)actin is present in these structures, but the nature of the actin isoform has not been studied before. We here show that both cytoplasmic actin isoforms, β- and γ-actin, are present in the invadopodia of MDA-MB-231 breast cancer cells cultured on a 2D-surface, where they colocalize with the invadopodial marker cortactin. Invadopodial structures formed by the cells in a 3D-collagen matrix also contain β- and γ-actin. We demonstrate this using isoform-specific antibodies and expression of fluorescently-tagged actin isoforms. Additionally, using simultaneous expression of differentially tagged β- and γ-actin in cells, we show that the actin isoforms are present together in a single invadopodium. Cells with an increased level of β- or γ-actin, display a similar increase in the number and size of invadopodia in comparison to control cells. Moreover, increasing the level of either actin isoforms also increases invasion velocity.
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Affiliation(s)
- Aleksandra Simiczyjew
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland.
| | - Antonina Joanna Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Christophe Ampe
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Maria Malicka-Błaszkiewicz
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Marleen van Troys
- Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
| | - Dorota Nowak
- Department of Cell Pathology, Faculty of Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383 Wroclaw, Poland
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Hundt N, Preller M, Swolski O, Ang AM, Mannherz HG, Manstein DJ, Müller M. Molecular mechanisms of disease-related human β-actin mutations p.R183W and p.E364K. FEBS J 2014; 281:5279-91. [PMID: 25255767 DOI: 10.1111/febs.13068] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 09/06/2014] [Accepted: 09/22/2014] [Indexed: 12/30/2022]
Abstract
Cytoplasmic β-actin supports fundamental cellular processes in healthy and diseased cells including cell adhesion, migration, cytokinesis and maintenance of cell polarity. Mutations in ACTB, the gene encoding cytoplasmic β-actin, lead to severe disorders with a broad range of symptoms. The two dominant heterozygous gain-of-function β-actin mutations p.R183W and p.E364K were identified in patients with developmental malformations, deafness and juvenile-onset dystonia (p.R183W) and neutrophil dysfunction (p.E364K). Here, we report the recombinant production and functional characterization of the two mutant proteins. Arg183 is located near the nucleotide-binding pocket of actin. Our results from biochemical studies and molecular dynamics simulations show that replacement by a tryptophan residue at position 183 establishes an unusual stacking interaction with Tyr69 that perturbs nucleotide release from actin monomers and polymerization behavior by inducing a closed state conformation. The replacement of Glu364 by a lysine residue appears to act as an allosteric trigger event leading to the preferred formation of the closed state. Thus, our approach indicates that both mutations affect interdomain mobility and nucleotide interactions as a basis for the formation of disease phenotypes in patients.
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Affiliation(s)
- Nikolas Hundt
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
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11
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Simiczyjew A, Mazur AJ, Popow-Woźniak A, Malicka-Błaszkiewicz M, Nowak D. Effect of overexpression of β- and γ-actin isoforms on actin cytoskeleton organization and migration of human colon cancer cells. Histochem Cell Biol 2014; 142:307-22. [PMID: 24682235 PMCID: PMC4133152 DOI: 10.1007/s00418-014-1199-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2014] [Indexed: 01/26/2023]
Abstract
Actins are eukaryotic proteins, which are involved in diverse cellular functions including muscle contraction, cell motility, adhesion and maintenance of cell shape. Cytoplasmic actin isoforms β and γ are ubiquitously expressed and essential for cell functioning. However, their unique contributions are not very well understood. The aim of this study was to determine the effect of β- and γ-actin overexpression on the migration capacity and actin cytoskeleton organization of human colon adenocarcinoma BE cells. In cells overexpressing β- or γ-actin, distinct cytoskeletal actin rearrangements were observed under the laser scanning confocal microscope. Overexpressed actins localized at the submembranous region of the cell body, especially near to the leading edge and on the tips of pseudopodia. The cells transfected with plasmids containing cDNA for β- or γ-actin were characterized by increased migration and invasion capacities. However, the migration velocity was statistically significantly higher only in the case of γ-actin overexpressing cells. In conclusion, the increased level of β- or γ-actin leads to actin cytoskeletal remodeling followed by an increase in migration and invasion capacities of human colon BE cells. These data suggest that expression of both actin isoforms has an impact on cancer cell motility, with the subtle predominance of γ-actin, and may influence invasiveness of human colon cancer.
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Affiliation(s)
- Aleksandra Simiczyjew
- Department of Cell Pathology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Antonina Joanna Mazur
- Department of Cell Pathology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Agnieszka Popow-Woźniak
- Department of Cell Pathology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Maria Malicka-Błaszkiewicz
- Department of Cell Pathology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Dorota Nowak
- Department of Cell Pathology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
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Szaro BG, Strong MJ. Regulation of Cytoskeletal Composition in Neurons: Transcriptional and Post-transcriptional Control in Development, Regeneration, and Disease. Advances in Neurobiology 2011. [DOI: 10.1007/978-1-4419-6787-9_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Tondeleir D, Vandamme D, Vandekerckhove J, Ampe C, Lambrechts A. Actin isoform expression patterns during mammalian development and in pathology: insights from mouse models. ACTA ACUST UNITED AC 2009; 66:798-815. [PMID: 19296487 DOI: 10.1002/cm.20350] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The dynamic actin cytoskeleton, consisting of six actin isoforms in mammals and a variety of actin binding proteins is essential for all developmental processes and for the viability of the adult organism. Actin isoform specific functions have been proposed for muscle contraction, cell migration, endo- and exocytosis and maintaining cell shape. However, these specific functions for each of the actin isoforms during development are not well understood. Based on transgenic mouse models, we will discuss the expression patterns of the six conventional actin isoforms in mammals during development and adult life. Ablation of actin genes usually leads to lethality and affects expression of other actin isoforms at the cell or tissue level. A good knowledge of their expression and functions will contribute to fully understand severe phenotypes or diseases caused by mutations in actin isoforms.
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Affiliation(s)
- Davina Tondeleir
- Department of Medical Protein Research, Flanders Interuniversity Institute for Biotechnology (VIB), Albert Baertsoenkaai 3, Ghent, Belgium
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Vandamme D, Lambert E, Waterschoot D, Cognard C, Vandekerckhove J, Ampe C, Constantin B, Rommelaere H. alpha-Skeletal muscle actin nemaline myopathy mutants cause cell death in cultured muscle cells. Biochim Biophys Acta 2009; 1793:1259-71. [PMID: 19393268 DOI: 10.1016/j.bbamcr.2009.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 03/24/2009] [Accepted: 04/14/2009] [Indexed: 11/24/2022]
Abstract
Nemaline myopathy is a neuromuscular disorder, characterized by muscle weakness and hypotonia and is, in 20% of the cases, caused by mutations in the gene encoding alpha-skeletal muscle actin, ACTA1. It is a heterogeneous disease with various clinical phenotypes and severities. In patients the ultrastructure of muscle cells is often disturbed by nemaline rods and it is thought this is the cause for muscle weakness. To search for possible defects during muscle cell differentiation we expressed alpha-actin mutants in myoblasts and allowed these cells to differentiate into myotubes. Surprisingly, we observed two striking new phenotypes in differentiating myoblasts: rounding up of cells and bleb formation, two features reminiscent of apoptosis. Indeed expression of these mutants induced cell death with apoptotic features in muscle cell culture, using AIF and endonuclease G, in a caspase-independent but calpain-dependent pathway. This is the first report on a common cellular defect induced by NM causing actin mutants, independent of their biochemical phenotypes or rod and aggregate formation capacity. These data suggest that lack of type II fibers or atrophy observed in nemaline myopathy patients may be also due to an increased number of dying muscle cells.
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Affiliation(s)
- Drieke Vandamme
- Department of Biochemistry, Ghent University, A. Baertsoenkaai 3, B-9000, Gent, Belgium
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Vandamme D, Rommelaere H, Lambert E, Waterschoot D, Vandekerckhove J, Constantin B, Ampe C. α-Skeletal muscle actin mutants causing different congenital myopathies induce similar cytoskeletal defects in cell line cultures. ACTA ACUST UNITED AC 2009; 66:179-92. [DOI: 10.1002/cm.20340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Vandamme D, Lambert E, Waterschoot D, Tondeleir D, Vandekerckhove J, Machesky LM, Constantin B, Rommelaere H, Ampe C. Phenotypes induced by NM causing alpha-skeletal muscle actin mutants in fibroblasts, Sol 8 myoblasts and myotubes. BMC Res Notes 2009; 2:40. [PMID: 19284548 DOI: 10.1186/1756-0500-2-40] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Accepted: 03/10/2009] [Indexed: 11/15/2022] Open
Abstract
Background Nemaline myopathy is a neuromuscular disorder characterized by the presence of nemaline bodies in patient muscles. 20% of the cases are associated with α-skeletal muscle actin mutations. We previously showed that actin mutations can cause four different biochemical phenotypes and that expression of NM associated actin mutants in fibroblasts, myoblasts and myotubes induces a range of cellular defects. Findings We conducted the same biochemical experiments for twelve new actin mutants associated with nemaline myopathy. We observed folding and polymerization defects. Immunostainings of these and eight other mutants in transfected cells revealed typical cellular defects such as nemaline rods or aggregates, decreased incorporation in F-actin structures, membrane blebbing, the formation of thickened actin fibres and cell membrane blebbing in myotubes. Conclusion Our results confirm that NM associated α-actin mutations induce a range of defects at the biochemical level as well as in cultured fibroblasts and muscle cells.
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Abstract
Mutations in human alpha-skeletal actin have been implicated in causing congenital nemaline myopathy, a disease characterized histopathologically by nemaline bodies in skeletal muscle and manifested in the patient as skeletal muscle weakness. Here we investigate the functional effects of three severe nemaline myopathy mutations (V43F, A138P, and R183G) in human alpha-skeletal actin. Wild-type and mutant actins were expressed and purified from the baculovirus/insect cell expression system. The mutations are located in different subdomains of actin; Val-43 is located in a flexible loop of subdomain 2, Ala-138 is near a hydrophobic cleft in the "hinge" region between subdomains 1 and 3, and Arg-183 is near the nucleotide-binding site. None of the three mutations affected the folding of the actin monomer, the velocity at which skeletal myosin moves actin in an in vitro motility assay, or the relative average isometric force supported by F-actin. Defects in fundamental actomyosin interactions are, therefore, unlikely to account for the muscle weakness observed in affected patients. There were, however, significant changes observed in the polymerization kinetics of V43F and A138P and in the rate of nucleotide release for V43F. No detectable defect was found for R183G. If these subtle changes in polymerization observed in vitro are amplified in the context of the sarcomere, it could in principle be one of the primary insults that triggers the development of nemaline myopathy.
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Affiliation(s)
- Becky M Miller
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405, USA
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Yates SP, Otley MD, Dawson JF. Overexpression of cardiac actin with baculovirus is promoter dependent. Arch Biochem Biophys 2007; 466:58-65. [PMID: 17765196 DOI: 10.1016/j.abb.2007.07.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/09/2007] [Accepted: 07/18/2007] [Indexed: 10/23/2022]
Abstract
The influence of the promoter and an N-terminal hexahistidine tag on human cardiac actin (ACTC) expression and function was investigated using four baculovirus constructs. It was found that both non-tagged ACTC and hisACTC expression from the p10 promoter was higher than from the polh promoter. Characterization showed that an N-terminal hexahistidine tag has a negative effect on ACTC. Recombinant ACTC inhibits DNase-I and binds myosin S1, indicative of proper folding. Our data support the hypothesis that the actin protein down-regulates the polh promoter.
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Affiliation(s)
- Susan P Yates
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ont., Canada N1G 2W1
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