1
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Hummel DR, Hakala M, Toret CP, Kaksonen M. Bsp1, a fungal CPI motif protein, regulates actin filament capping in endocytosis and cytokinesis. Mol Biol Cell 2024; 35:br6. [PMID: 38088874 PMCID: PMC10881157 DOI: 10.1091/mbc.e23-10-0391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/28/2023] [Accepted: 12/07/2023] [Indexed: 01/14/2024] Open
Abstract
The capping of barbed filament ends is a fundamental mechanism for actin regulation. Capping protein controls filament growth and actin turnover in cells by binding to the barbed ends of the filaments with high affinity and slow off-rate. The interaction between capping protein and actin is regulated by capping protein interaction (CPI) motif proteins. We identified a novel CPI motif protein, Bsp1, which is involved in cytokinesis and endocytosis in budding yeast. We demonstrate that Bsp1 is an actin binding protein with a high affinity for capping protein via its CPI motif. In cells, Bsp1 regulates capping protein at endocytic sites and is a major recruiter of capping protein to the cytokinetic actin ring. Lastly, we define Bsp1-related proteins as a distinct fungi-specific CPI protein group. Our results suggest that Bsp1 promotes actin filament capping by the capping protein. This study establishes Bsp1 as a new capping protein regulator and promising candidate to regulate actin networks in fungi.
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Affiliation(s)
- Daniel R. Hummel
- Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland
| | - Markku Hakala
- Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland
| | | | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, 1205 Geneva, Switzerland
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2
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Alimov N, Hoeprich GJ, Padrick SB, Goode BL. Cyclase-associated protein interacts with actin filament barbed ends to promote depolymerization and formin displacement. J Biol Chem 2023; 299:105367. [PMID: 37863260 PMCID: PMC10692737 DOI: 10.1016/j.jbc.2023.105367] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/04/2023] [Accepted: 10/12/2023] [Indexed: 10/22/2023] Open
Abstract
Cyclase-associated protein (CAP) has emerged as a central player in cellular actin turnover, but its molecular mechanisms of action are not yet fully understood. Recent studies revealed that the N terminus of CAP interacts with the pointed ends of actin filaments to accelerate depolymerization in conjunction with cofilin. Here, we use in vitro microfluidics-assisted TIRF microscopy to show that the C terminus of CAP promotes depolymerization at the opposite (barbed) ends of actin filaments. In the absence of actin monomers, full-length mouse CAP1 and C-terminal halves of CAP1 (C-CAP1) and CAP2 (C-CAP2) accelerate barbed end depolymerization. Using mutagenesis and structural modeling, we show that these activities are mediated by the WH2 and CARP domains of CAP. In addition, we observe that CAP collaborates with profilin to accelerate barbed end depolymerization and that these effects depend on their direct interaction, providing the first known example of CAP-profilin collaborative effects in regulating actin. In the presence of actin monomers, CAP1 attenuates barbed end growth and promotes formin dissociation. Overall, these findings demonstrate that CAP uses distinct domains and mechanisms to interact with opposite ends of actin filaments and drive turnover. Further, they contribute to the emerging view of actin barbed ends as sites of dynamic molecular regulation, where numerous proteins compete and cooperate with each other to tune polymer dynamics, similar to the rich complexity seen at microtubule ends.
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Affiliation(s)
- Nikita Alimov
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Gregory J Hoeprich
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA
| | - Shae B Padrick
- Department of Biochemistry and Molecular Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, USA.
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3
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Molina-Pelayo C, Olguin P, Mlodzik M, Glavic A. The conserved Pelado/ZSWIM8 protein regulates actin dynamics by promoting linear actin filament polymerization. Life Sci Alliance 2022; 5:5/12/e202201484. [PMID: 35940847 PMCID: PMC9375228 DOI: 10.26508/lsa.202201484] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/24/2022] Open
Abstract
Actin filament polymerization can be branched or linear, which depends on the associated regulatory proteins. Competition for actin monomers occurs between proteins that induce branched or linear actin polymerization. Cell specialization requires the regulation of actin filaments to allow the formation of cell type-specific structures, like cuticular hairs in Drosophila, formed by linear actin filaments. Here, we report the functional analysis of CG34401/pelado, a gene encoding a SWIM domain-containing protein, conserved throughout the animal kingdom, called ZSWIM8 in mammals. Mutant pelado epithelial cells display actin hair elongation defects. This phenotype is reversed by increasing actin monomer levels or by either pushing linear actin polymerization or reducing branched actin polymerization. Similarly, in hemocytes, Pelado is essential to induce filopodia, a linear actin-based structure. We further show that this function of Pelado/ZSWIM8 is conserved in human cells, where Pelado inhibits branched actin polymerization in a cell migration context. In summary, our data indicate that the function of Pelado/ZSWIM8 in regulating actin cytoskeletal dynamics is conserved, favoring linear actin polymerization at the expense of branched filaments.
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Affiliation(s)
- Claudia Molina-Pelayo
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Departamento de Biología, Centro FONDAP de Regulación del Genoma, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Patricio Olguin
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA .,Departamento de Neurociencia, Programa de Genética Humana, Instituto de Ciencias Biomédicas, Instituto de Neurociencia Biomédica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marek Mlodzik
- Department of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alvaro Glavic
- Departamento de Biología, Centro FONDAP de Regulación del Genoma, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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4
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Tur-Gracia S, Martinez-Quiles N. Emerging functions of cytoskeletal proteins in immune diseases. J Cell Sci 2021; 134:134/3/jcs253534. [PMID: 33558442 DOI: 10.1242/jcs.253534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Immune cells are especially dependent on the proper functioning of the actin cytoskeleton, and both innate and adaptive responses rely on it. Leukocytes need to adhere not only to substrates but also to cells in order to form synapses that pass on instructions or kill infected cells. Neutrophils literally squeeze their cell body during blood extravasation and efficiently migrate to the inflammatory focus. Moreover, the development of immune cells requires the remodeling of their cytoskeleton as it depends on, among other processes, adhesive contacts and migration. In recent years, the number of reports describing cytoskeletal defects that compromise the immune system has increased immensely. Furthermore, a new emerging paradigm points toward a role for the cellular actin content as an essential component of the so-called homeostasis-altering molecular processes that induce the activation of innate immune signaling pathways. Here, we review the role of critical actin-cytoskeleton-remodeling proteins, including the Arp2/3 complex, cofilin, coronin and WD40-repeat containing protein 1 (WDR1), in immune pathophysiology, with a special focus on autoimmune and autoinflammatory traits.
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Affiliation(s)
- Sara Tur-Gracia
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, 28040 Madrid, Spain
| | - Narcisa Martinez-Quiles
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, 28040 Madrid, Spain .,Gregorio Marañón Health Research Institute, 28007 Madrid, Spain
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5
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Janssen E, Geha RS. Primary immunodeficiencies caused by mutations in actin regulatory proteins. Immunol Rev 2019; 287:121-134. [PMID: 30565251 DOI: 10.1111/imr.12716] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/31/2018] [Indexed: 12/31/2022]
Abstract
The identification of patients with monogenic gene defects have illuminated the function of different proteins in the immune system, including proteins that regulate the actin cytoskeleton. Many of these actin regulatory proteins are exclusively expressed in leukocytes and regulate the formation and branching of actin filaments. Their absence or abnormal function leads to defects in immune cell shape, cellular projections, migration, and signaling. Through the study of patients' mutations and generation of mouse models that recapitulate the patients' phenotypes, our laboratory and others have gained a better understanding of the role these proteins play in cell biology and the underlying pathogenesis of immunodeficiencies and immune dysregulatory syndromes.
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Affiliation(s)
- Erin Janssen
- Division of Immunology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Raif S Geha
- Division of Immunology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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6
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Hegsted A, Votra S, Christophe AM, Yingling CV, Sundaramurthy S, Pruyne D. Functional importance of an inverted formin C-terminal tail at morphologically dynamic epithelial junctions. Cytoskeleton (Hoboken) 2019; 76:322-336. [PMID: 31215743 DOI: 10.1002/cm.21547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/30/2019] [Accepted: 06/09/2019] [Indexed: 11/10/2022]
Abstract
Epithelial cell-cell junctions have dual roles of accommodating morphological changes in an epithelium, while maintaining cohesion during those changes. An abundance of junction proteins has been identified, but many details on how intercellular junctions respond to morphological changes remain unclear. In Caenorhabditis elegans, the spermatheca is an epithelial sac that repeatedly dilates and constricts to allow ovulation. It is thought that the junctions between spermatheca epithelial cells undergo reversible partial unzipping to allow rapid dilation. Previously, we found that EXC-6, a C. elegans protein homolog of the human disease-associated formin INF2, is expressed in the spermatheca and promotes oocyte entry. We show here that EXC-6 localizes toward the apical aspect of the spermatheca epithelial junctions, and that the EXC-6-labeled junction domains "unzip" and dramatically flatten with oocyte entry into the spermatheca. We demonstrate that the C-terminal tail of EXC-6 is necessary and sufficient for junction localization. Moreover, expression of the tail alone worsens ovulation defects, suggesting this region not only mediates EXC-6 localization, but also interacts with other components important for junction remodeling.
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Affiliation(s)
- Anna Hegsted
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - SarahBeth Votra
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - Amylisa M Christophe
- Department of Clinical Laboratory Sciences, SUNY Upstate Medical University, Syracuse, New York
| | - Curtis V Yingling
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - Sumana Sundaramurthy
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - David Pruyne
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
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7
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Miller EW, Blystone SD. The carboxy-terminus of the formin FMNL1ɣ bundles actin to potentiate adenocarcinoma migration. J Cell Biochem 2019; 120:14383-14404. [PMID: 30977161 DOI: 10.1002/jcb.28694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 12/31/2022]
Abstract
The formin family of proteins contributes to spatiotemporal control of actin cytoskeletal rearrangements during motile cell activities. The FMNL subfamily exhibits multiple mechanisms of linear actin filament formation and organization. Here we report novel actin-modifying functions of FMNL1 in breast adenocarcinoma migration models. FMNL1 is required for efficient cell migration and its three isoforms exhibit distinct localization. Suppression of FMNL1 protein expression results in a significant impairment of cell adhesion, migration, and invasion. Overexpression of FMNL1ɣ, but not FMNL1β or FMNL1α, enhances cell adhesion independent of the FH2 domain and FMNL1ɣ rescues migration in cells depleted of all three endogenous isoforms. While FMNL1ɣ inhibits actin assembly in vitro, it facilitates bundling of filamentous actin independent of the FH2 domain. The unique interactions of FMNL1ɣ with filamentous actin provide a new understanding of formin domain functions and its effect on motility of diverse cell types suggest a broader role than previously realized.
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Affiliation(s)
- Eric W Miller
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
| | - Scott D Blystone
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York
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8
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Isogai T, Danuser G. Discovery of functional interactions among actin regulators by analysis of image fluctuations in an unperturbed motile cell system. Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0110. [PMID: 29632262 DOI: 10.1098/rstb.2017.0110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/30/2017] [Indexed: 01/06/2023] Open
Abstract
Cell migration is driven by propulsive forces derived from polymerizing actin that pushes and extends the plasma membrane. The underlying actin network is constantly undergoing adaptation to new mechano-chemical environments and intracellular conditions. As such, mechanisms that regulate actin dynamics inherently contain multiple feedback loops and redundant pathways. Given the highly adaptable nature of such a system, studies that use only perturbation experiments (e.g. knockdowns, overexpression, pharmacological activation/inhibition, etc.) are challenged by the nonlinearity and redundancy of the pathway. In these pathway configurations, perturbation experiments at best describe the function(s) of a molecular component in an adapting (e.g. acutely drug-treated) or fully adapted (e.g. permanent gene silenced) cell system, where the targeted component now resides in a non-native equilibrium. Here, we propose how quantitative live-cell imaging and analysis of constitutive fluctuations of molecular activities can overcome these limitations. We highlight emerging actin filament barbed-end biology as a prime example of a complex, nonlinear molecular process that requires a fluctuation analytic approach, especially in an unperturbed cellular system, to decipher functional interactions of barbed-end regulators, actin polymerization and membrane protrusion.This article is part of the theme issue 'Self-organization in cell biology'.
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Affiliation(s)
- Tadamoto Isogai
- Department of Cell Biology, Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gaudenz Danuser
- Department of Cell Biology, Lyda Hill Department of Bioinformatics, UT Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Yavorski JM, Blanck G. Smoking correlates with increased cytoskeletal protein-related coding region mutations in the lung and head and neck datasets of the cancer genome atlas. Physiol Rep 2017; 4:4/24/e13045. [PMID: 28039401 PMCID: PMC5210378 DOI: 10.14814/phy2.13045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 10/27/2016] [Accepted: 10/28/2016] [Indexed: 12/19/2022] Open
Abstract
Cancer from smoking tobacco is considered dependent on mutagens, but significant molecular aspects of smoking‐specific, cancer development remain unknown. We defined sets of coding regions for oncoproteins, tumor suppressor proteins, and cytoskeletal‐related proteins that were compared between nonsmokers and smokers, for mutation occurrences, in the lung adenocarcinoma (LUAD), head and neck squamous carcinoma (HNSC), bladder carcinoma (BLCA), and pancreatic adenocarcinoma ( PAAD) datasets from the cancer genome atlas (TCGA). We uncovered significant differences in overall mutation rates, and in mutation rates in cytoskeletal protein‐related coding regions (CPCRs, including extracellular matrix protein coding regions), between nonsmokers and smokers in LUAD and HNSC (P < 0.001), raising the question of whether the CPCR mutation differences lead to different clinical courses for nonsmoker and smoker cancers. Another important question inspired by these results is, whether high smoker cancer mutation rates would facilitate genotoxicity or neoantigen‐based therapies. No significant, mutation‐based differences were found in the BLCA or PAAD datasets, between nonsmokers and smokers. However, a significant difference was uncovered for the average number of overall cancer mutations, in LUAD, for persons who stopped smoking more than 15 years ago, compared with more recent smokers (P < 0.032).
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Affiliation(s)
- John M Yavorski
- Department of Molecular Medicine, Morsani College of Medicine University of South Florida, Tampa, Florida
| | - George Blanck
- Department of Molecular Medicine, Morsani College of Medicine University of South Florida, Tampa, Florida .,Immunology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida
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10
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Pruyne D. Probing the origins of metazoan formin diversity: Evidence for evolutionary relationships between metazoan and non-metazoan formin subtypes. PLoS One 2017; 12:e0186081. [PMID: 28982189 PMCID: PMC5628938 DOI: 10.1371/journal.pone.0186081] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/25/2017] [Indexed: 11/18/2022] Open
Abstract
Formins are proteins that assist in regulating cytoskeletal organization through interactions with actin filaments and microtubules. Metazoans encode nine distinct formin subtypes based on sequence similarity, potentially allowing for great functional diversity for these proteins. Through the evolution of the eukaryotes, formins are believed to have repeatedly undergone rounds of gene duplications, followed by diversification and domain shuffling, but previous phylogenetic analyses have shed only a little light on the specific origins of different formin subtypes. To improve our understanding of this in the case of the metazoan formins, phylogenetic comparisons were made here of a broad range of metazoan and non-metazoan formin sequences. This analysis suggests a model in which eight of the nine metazoan formin subtypes arose from two ancestral proteins that were present in an ancient unikont ancestor. Additionally, evidence is shown suggesting the common ancestor of unikonts and bikonts was likely to have encoded at least two formins, a canonical Drf-type protein and a formin bearing a PTEN-like domain.
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Affiliation(s)
- David Pruyne
- Department of Cell and Developmental Biology, State University of New York Upstate Medical University, Syracuse, NY, United States of America
- * E-mail:
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11
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González-Rodríguez VE, Garrido C, Cantoral JM, Schumacher J. The F-actin capping protein is required for hyphal growth and full virulence but is dispensable for septum formation in Botrytis cinerea. Fungal Biol 2016; 120:1225-35. [PMID: 27647239 DOI: 10.1016/j.funbio.2016.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/05/2016] [Accepted: 07/07/2016] [Indexed: 01/20/2023]
Abstract
Filamentous (F-) actin is an integral part of the cytoskeleton allowing for cell growth, intracellular motility, and cytokinesis of eukaryotic cells. Its assembly from G-actin monomers and its disassembly are tightly regulated processes involving a number of actin-binding proteins (ABPs) such as F-actin nucleators and cross-linking proteins. F-actin capping protein (CP) is an alpha/beta heterodimer known from yeast and higher eukaryotes to bind to the fast growing ends of the actin filaments stabilizing them. In this study, we identified the orthologs of the two CP subunits, named BcCPA1 and BcCPB1, in the plant pathogenic fungus Botrytis cinerea and showed that the two proteins physically interact in a yeast two-hybrid approach. GFP-BcCPA1 fusion proteins were functional and localized to the assumed sites of F-actin accumulation, i.e. to the hyphal tips and the sites of actin ring formation. Deletion of bccpa1 had a profound effect on hyphal growth, morphogenesis, and virulence indicating the importance of F-actin capping for an intact actin cytoskeleton. As polarized growth - unlike septum formation - is impaired in the mutants, it can be concluded that the organization and/or localization of actin patches and cables are disturbed rather than the functionality of the actin rings.
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Affiliation(s)
- Victoria E González-Rodríguez
- Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain.
| | - Carlos Garrido
- Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain.
| | - Jesús M Cantoral
- Departamento de Biomedicina, Biotecnología y Salud Pública, Laboratorio de Microbiología, Facultad de Ciencias de Mar y Ambientales, Instituto Universitario de Investigación Vitivinícola y Agroalimentaria (IVAGRO), Universidad de Cádiz, Polígono Río San Pedro, 11510 Puerto Real, Spain.
| | - Julia Schumacher
- Institut für Biologie und Biotechnologie der Pflanzen (IBBP), Westfälische Wilhelms-Universität Münster, Schlossplatz 8, 48143 Münster, Germany.
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12
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Pernier J, Shekhar S, Jegou A, Guichard B, Carlier MF. Profilin Interaction with Actin Filament Barbed End Controls Dynamic Instability, Capping, Branching, and Motility. Dev Cell 2016; 36:201-14. [PMID: 26812019 PMCID: PMC4729542 DOI: 10.1016/j.devcel.2015.12.024] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/09/2015] [Accepted: 12/22/2015] [Indexed: 12/22/2022]
Abstract
Cell motility and actin homeostasis depend on the control of polarized growth of actin filaments. Profilin, an abundant regulator of actin dynamics, supports filament assembly at barbed ends by binding G-actin. Here, we demonstrate how, by binding and destabilizing filament barbed ends at physiological concentrations, profilin also controls motility, cell migration, and actin homeostasis. Profilin enhances filament length fluctuations. Profilin competes with Capping Protein at barbed ends, which generates a lower amount of profilin-actin than expected if barbed ends were tightly capped. Profilin competes with barbed end polymerases, such as formins and VopF, and inhibits filament branching by WASP-Arp2/3 complex by competition for filament barbed ends, accounting for its as-yet-unknown effects on motility and metastatic cell migration observed in this concentration range. In conclusion, profilin is a major coordinator of polarized growth of actin filaments, controlled by competition between barbed end cappers, trackers, destabilizers, and filament branching machineries. The binding of profilin to barbed ends accounts for its effects on cell migration Profilin enhances length fluctuations of actin filaments by destabilizing barbed ends Profilin competes with capping protein at filament barbed ends Profilin competes with polymerases and filament branching machineries at barbed ends
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Affiliation(s)
- Julien Pernier
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Shashank Shekhar
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Antoine Jegou
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Bérengère Guichard
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France.
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13
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Tzelos T, Matthews JB, Buck AH, Simbari F, Frew D, Inglis NF, McLean K, Nisbet AJ, Whitelaw CBA, Knox DP, McNeilly TN. A preliminary proteomic characterisation of extracellular vesicles released by the ovine parasitic nematode, Teladorsagia circumcincta. Vet Parasitol 2016; 221:84-92. [PMID: 27084478 PMCID: PMC4867787 DOI: 10.1016/j.vetpar.2016.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 12/21/2022]
Abstract
Teladorsagia circumcincta is a major cause of ovine parasitic gastroenteritis in temperate climatic regions. The development of high levels of anthelmintic resistance in this nematode species challenges its future control. Recent research indicates that many parasite species release extracellular vesicles into their environment, many of which have been classified as endocytic in origin, termed exosomes. These vesicles are considered to play important roles in the intercellular communication between parasites and their hosts, and thus represent potentially useful targets for novel control strategies. Here, we demonstrate that exosome-like extracellular vesicles can be isolated from excretory-secretory (ES) products released by T. circumcincta fourth stage larvae (Tci-L4ES). Furthermore, we perform a comparative proteomic analysis of vesicle-enriched and vesicle-free Tci-L4ES. Approximately 73% of the proteins identified in the vesicle-enriched fraction were unique to this fraction, whilst the remaining 27% were present in both vesicle-enriched and vesicle-free fraction. These unique proteins included structural proteins, nuclear proteins, metabolic proteins, proteolytic enzymes and activation-associated secreted proteins. Finally, we demonstrate that molecules present within the vesicles-enriched material are targets of the IgA and IgG response in T. circumcincta infected sheep, and could potentially represent useful targets for future vaccine intervention studies.
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Affiliation(s)
- Thomas Tzelos
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK.
| | - Jacqueline B Matthews
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Amy H Buck
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, EH9 3JL, Edinburgh, UK
| | - Fabio Simbari
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, EH9 3JL, Edinburgh, UK
| | - David Frew
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Neil F Inglis
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Kevin McLean
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Alasdair J Nisbet
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - C Bruce A Whitelaw
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian,EH25 9RG, Edinburgh, UK
| | - David P Knox
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
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14
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Montaville P, Kühn S, Compper C, Carlier MF. Role of the C-terminal Extension of Formin 2 in Its Activation by Spire Protein and Processive Assembly of Actin Filaments. J Biol Chem 2015; 291:3302-18. [PMID: 26668326 DOI: 10.1074/jbc.m115.681379] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Indexed: 11/06/2022] Open
Abstract
Formin 2 (Fmn2), a member of the FMN family of formins, plays an important role in early development. This formin cooperates with profilin and Spire, a WASP homology domain 2 (WH2) repeat protein, to stimulate assembly of a dynamic cytoplasmic actin meshwork that facilitates translocation of the meiotic spindle in asymmetric division of mouse oocytes. The kinase-like non-catalytic domain (KIND) of Spire directly interacts with the C-terminal extension of the formin homology domain 2 (FH2) domain of Fmn2, called FSI. This direct interaction is required for the synergy between the two proteins in actin assembly. We have recently demonstrated how Spire, which caps barbed ends via its WH2 domains, activates Fmn2. Fmn2 by itself associates very poorly to filament barbed ends but is rapidly recruited to Spire-capped barbed ends via the KIND domain, and it subsequently displaces Spire from the barbed end to elicit rapid processive assembly from profilin·actin. Here, we address the mechanism by which Spire and Fmn2 compete at barbed ends and the role of FSI in orchestrating this competition as well as in the processivity of Fmn2. We have combined microcalorimetric, fluorescence, and hydrodynamic binding assays, as well as bulk solution and single filament measurements of actin assembly, to show that removal of FSI converts Fmn2 into a Capping Protein. This activity is mimicked by association of KIND to Fmn2. In addition, FSI binds actin at filament barbed ends as a weak capper and plays a role in displacing the WH2 domains of Spire from actin, thus allowing the association of actin-binding regions of FH2 to the barbed end.
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Affiliation(s)
- Pierre Montaville
- From the Cytoskeleton Dynamics and Motility, Institut de Biologie Intégrative de la Cellule, CNRS, 91198 Gif-sur-Yvette, France
| | - Sonja Kühn
- From the Cytoskeleton Dynamics and Motility, Institut de Biologie Intégrative de la Cellule, CNRS, 91198 Gif-sur-Yvette, France
| | - Christel Compper
- From the Cytoskeleton Dynamics and Motility, Institut de Biologie Intégrative de la Cellule, CNRS, 91198 Gif-sur-Yvette, France
| | - Marie-France Carlier
- From the Cytoskeleton Dynamics and Motility, Institut de Biologie Intégrative de la Cellule, CNRS, 91198 Gif-sur-Yvette, France
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15
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Parry ML, Blanck G. Flat cells come full sphere: Are mutant cytoskeletal-related proteins oncoprotein-monsters or useful immunogens? Hum Vaccin Immunother 2015. [PMID: 26225584 DOI: 10.1080/21645515.2015.1073428] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Osteogenesis imperfecta is inherited as a dominant disease because if one allele is mutated, it contributes a mutant, destructive subunit polypeptide to collagen, which requires many subunits to form normal, polymeric, collagenous structures. Recent cancer genome atlas (TCGA) data indicate that cytoskeletal-related proteins are among the most commonly mutated proteins in human cancers, in distinct mutation frequency groups, i.e., including low mutation frequency groups. Part of the explanation for this observation is likely to be the fact that many of the coding regions for these proteins are very large, and indeed, it is likely these coding regions are mutated in many cells that never become cancerous. However, it would not be surprising if mutations in cytoskeletal proteins, when combined with oncoprotein or tumor suppressor protein mutations, had significant impacts on cancer development, for a number of reasons, including results obtained almost 5 decades ago indicating that well-spread cells in tissue culture, with well-formed cytoskeletons, were less tumorigenic than spherical cells with disrupted cytoskeletons. This raises the question, are mutant cytoskeletal proteins, which would likely interfere with polymer formation, a new class of oncoproteins, in particular, dominant negative oncoproteins? If these proteins are so commonly mutant, could they be the bases for common cancer vaccines?
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Affiliation(s)
- Michele L Parry
- a Department of Molecular Medicine ; Morsani College of Medicine; University of South Florida ; Tampa , FL USA
| | - George Blanck
- a Department of Molecular Medicine ; Morsani College of Medicine; University of South Florida ; Tampa , FL USA.,b Immunology Program; Moffitt Cancer Center and Research Institute ; Tampa , FL USA
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16
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Control of polarized assembly of actin filaments in cell motility. Cell Mol Life Sci 2015; 72:3051-67. [PMID: 25948416 PMCID: PMC4506460 DOI: 10.1007/s00018-015-1914-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 04/02/2015] [Accepted: 04/23/2015] [Indexed: 10/25/2022]
Abstract
Actin cytoskeleton remodeling, which drives changes in cell shape and motility, is orchestrated by a coordinated control of polarized assembly of actin filaments. Signal responsive, membrane-bound protein machineries initiate and regulate polarized growth of actin filaments by mediating transient links with their barbed ends, which elongate from polymerizable actin monomers. The barbed end of an actin filament thus stands out as a hotspot of regulation of filament assembly. It is the target of both soluble and membrane-bound agonists as well as antagonists of filament assembly. Here, we review the molecular mechanisms by which various regulators of actin dynamics bind, synergize or compete at filament barbed ends. Two proteins can compete for the barbed end via a mutually exclusive binding scheme. Alternatively, two regulators acting individually at barbed ends may be bound together transiently to terminal actin subunits at barbed ends, leading to the displacement of one by the other. The kinetics of these reactions is a key in understanding how filament length and membrane-filament linkage are controlled. It is also essential for understanding how force is produced to shape membranes by mechano-sensitive, processive barbed end tracking machineries like formins and by WASP-Arp2/3 branched filament arrays. A combination of biochemical and biophysical approaches, including bulk solution assembly measurements using pyrenyl-actin fluorescence, single filament dynamics, single molecule fluorescence imaging and reconstituted self-organized filament assemblies, have provided mechanistic insight into the role of actin polymerization in motile processes.
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17
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Sweeney MO, Collins A, Padrick SB, Goode BL. A novel role for WAVE1 in controlling actin network growth rate and architecture. Mol Biol Cell 2014; 26:495-505. [PMID: 25473116 PMCID: PMC4310740 DOI: 10.1091/mbc.e14-10-1477] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
A novel functional role for WAVE1 is found that is lacking in N-WASP and WAVE2. Through its unique WH2 domain, WAVE1 dramatically reduces the rate of actin filament elongation independently of its interactions with the Arp2/3 complex. These findings help explain how cells build actin networks with distinct geometries and growth rates. Branched actin filament networks in cells are assembled through the combined activities of Arp2/3 complex and different WASP/WAVE proteins. Here we used TIRF and electron microscopy to directly compare for the first time the assembly kinetics and architectures of actin filament networks produced by Arp2/3 complex and dimerized VCA regions of WAVE1, WAVE2, or N-WASP. WAVE1 produced strikingly different networks from WAVE2 or N-WASP, which comprised unexpectedly short filaments. Further analysis showed that the WAVE1-specific activity stemmed from an inhibitory effect on filament elongation both in the presence and absence of Arp2/3 complex, which was observed even at low stoichiometries of WAVE1 to actin monomers, precluding an effect from monomer sequestration. Using a series of VCA chimeras, we mapped the elongation inhibitory effects of WAVE1 to its WH2 (“V”) domain. Further, mutating a single conserved lysine residue potently disrupted WAVE1's inhibitory effects. Taken together, our results show that WAVE1 has unique activities independent of Arp2/3 complex that can govern both the growth rates and architectures of actin filament networks. Such activities may underlie previously observed differences between the cellular functions of WAVE1 and WAVE2.
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Affiliation(s)
- Meredith O Sweeney
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Agnieszka Collins
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454
| | - Shae B Padrick
- Howard Hughes Medical Institute and Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Bruce L Goode
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454;
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