1
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Christophers B, Leahy SN, Soffar DB, von Saucken VE, Broadie K, Baylies MK. Muscle cofilin alters neuromuscular junction postsynaptic development to strengthen functional neurotransmission. Development 2024; 151:dev202558. [PMID: 38869008 PMCID: PMC11266751 DOI: 10.1242/dev.202558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 06/05/2024] [Indexed: 06/14/2024]
Abstract
Cofilin, an actin-severing protein, plays key roles in muscle sarcomere addition and maintenance. Our previous work found that Drosophila cofilin (DmCFL) knockdown in muscle causes progressive deterioration of muscle structure and function and produces features seen in nemaline myopathy caused by cofilin mutations. We hypothesized that disruption of actin cytoskeleton dynamics by DmCFL knockdown would impact other aspects of muscle development, and, thus, conducted an RNA-sequencing analysis that unexpectedly revealed upregulated expression of numerous neuromuscular junction (NMJ) genes. We found that DmCFL is enriched in the muscle postsynaptic compartment and that DmCFL muscle knockdown causes F-actin disorganization in this subcellular domain prior to the sarcomere defects observed later in development. Despite NMJ gene expression changes, we found no significant changes in gross presynaptic Bruchpilot active zones or total postsynaptic glutamate receptor levels. However, DmCFL knockdown resulted in mislocalization of GluRIIA class glutamate receptors in more deteriorated muscles and strongly impaired NMJ transmission strength. These findings expand our understanding of the roles of cofilin in muscle to include NMJ structural development and suggest that NMJ defects may contribute to the pathophysiology of nemaline myopathy.
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Affiliation(s)
- Briana Christophers
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - David B. Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Victoria E. von Saucken
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Mary K. Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
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2
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Advedissian T, Frémont S, Echard A. Cytokinetic abscission requires actin-dependent microtubule severing. Nat Commun 2024; 15:1949. [PMID: 38431632 PMCID: PMC10908825 DOI: 10.1038/s41467-024-46062-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
Cell division is completed by the abscission of the intercellular bridge connecting the daughter cells. Abscission requires the polymerization of an ESCRT-III cone close to the midbody to both recruit the microtubule severing enzyme spastin and scission the plasma membrane. Here, we found that the microtubule and the membrane cuts are two separate events that are regulated differently. Using HeLa cells, we uncovered that the F-actin disassembling protein Cofilin-1 controls the disappearance of a transient pool of branched F-actin which is precisely assembled at the tip of the ESCRT-III cone shortly before the microtubule cut. Functionally, Cofilin-1 and Arp2/3-mediated branched F-actin favor abscission by promoting local severing of the microtubules but do not participate later in the membrane scission event. Mechanistically, we propose that branched F-actin functions as a physical barrier that limits ESCRT-III cone elongation and thereby favors stable spastin recruitment. Our work thus reveals that F-actin controls the timely and local disassembly of microtubules required for cytokinetic abscission.
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Affiliation(s)
- Tamara Advedissian
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Stéphane Frémont
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France
| | - Arnaud Echard
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, Membrane Traffic and Cell Division Unit, 25-28 rue du Dr Roux, F-75015, Paris, France.
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3
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Christophers B, Leahy SN, Soffar DB, von Saucken VE, Broadie K, Baylies MK. Muscle cofilin alters neuromuscular junction postsynaptic development to strengthen functional neurotransmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.21.568166. [PMID: 38045306 PMCID: PMC10690168 DOI: 10.1101/2023.11.21.568166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Cofilin, an actin severing protein, plays critical roles in muscle sarcomere addition and maintenance. Our previous work has shown Drosophila cofilin (DmCFL) knockdown causes progressive deterioration of muscle structure and function and produces features seen in nemaline myopathy (NM) caused by cofilin mutations. We hypothesized that disruption of actin cytoskeleton dynamics by DmCFL knockdown would impact other aspects of muscle development, and, thus, conducted an RNA sequencing analysis which unexpectedly revealed upregulated expression of numerous neuromuscular junction (NMJ) genes. We found that DmCFL is enriched in the muscle postsynaptic compartment and that DmCFL deficiency causes F-actin disorganization in this subcellular domain prior to the sarcomere defects observed later in development. Despite NMJ gene expression changes, we found no significant changes in gross presynaptic Bruchpilot active zones or total postsynaptic glutamate receptor levels. However, DmCFL knockdown results in mislocalization of glutamate receptors containing the GluRIIA subunit in more deteriorated muscles and neurotransmission strength is strongly impaired. These findings expand our understanding of cofilin's roles in muscle to include NMJ structural development and suggest that NMJ defects may contribute to NM pathophysiology.
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Affiliation(s)
- Briana Christophers
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - David B. Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Victoria E. von Saucken
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Mary K. Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
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4
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Schiller NR, Almuhanna SA, Hoppe PE. UNC-82/NUAK kinase is required by myosin A, but not myosin B, to assemble and function in the thick filament arms of C. elegans striated muscle. Cytoskeleton (Hoboken) 2023. [PMID: 37983932 DOI: 10.1002/cm.21807] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/10/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023]
Abstract
The mechanisms that ensure proper assembly, activity, and turnover of myosin II filaments are fundamental to a diverse range of cellular processes. In Caenorhabditis elegans striated muscle, thick filaments contain two myosins that are functionally distinct and spatially segregated. Using transgenic double mutants, we demonstrate that the ability of increased myosin A expression to restore muscle structure and movement in myosin B mutants requires UNC-82/NUAK kinase activity. Myosin B function appears unaffected in the kinase-impaired unc-82(e1220) mutant: the recessive antimorphic effects on early assembly of paramyosin and myosin A in this mutant are counteracted by increased myosin B expression and exacerbated by loss of myosin B. Using chimeric myosins and motility assays, we mapped the region of myosin A that requires UNC-82 activity to a 531-amino-acid region of the coiled-coil rod. This region includes the 264-amino-acid Region 1, which is sufficient in chimeric myosins to rescue the essential filament-initiation function of myosin A, as well as two sites that interact with myosin head domains in the Interacting Heads Motif. A specific physical interaction between myosin A and UNC-82::GFP is supported by GFP labeling of ectopic myosin A filaments but not thin filaments. We hypothesize that UNC-82 regulates assembly competence of myosin A during parallel assembly in the filament arms.
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Affiliation(s)
- NaTasha R Schiller
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
- Biology Department, Wingate University, Wingate, North Carolina, USA
| | - Sarah A Almuhanna
- Clinical Laboratory Sciences, Imam Abdulrahman bin Faisal University, Dammam, Saudi Arabia
| | - Pamela E Hoppe
- Department of Biological Sciences, Western Michigan University, Kalamazoo, Michigan, USA
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Jafari G, Khan LA, Zhang H, Membreno E, Yan S, Dempsey G, Gobel V. Branched-chain actin dynamics polarizes vesicle trajectories and partitions apicobasal epithelial membrane domains. SCIENCE ADVANCES 2023; 9:eade4022. [PMID: 37379384 PMCID: PMC10306301 DOI: 10.1126/sciadv.ade4022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 05/24/2023] [Indexed: 06/30/2023]
Abstract
In prevailing epithelial polarity models, membrane- and junction-based polarity cues such as the partitioning-defective PARs specify the positions of apicobasal membrane domains. Recent findings indicate, however, that intracellular vesicular trafficking can determine the position of the apical domain, upstream of membrane-based polarity cues. These findings raise the question of how vesicular trafficking becomes polarized independent of apicobasal target membrane domains. Here, we show that the apical directionality of vesicle trajectories depends on actin dynamics during de novo polarized membrane biogenesis in the C. elegans intestine. We find that actin, powered by branched-chain actin modulators, determines the polarized distribution of apical membrane components, PARs, and itself. Using photomodulation, we demonstrate that F-actin travels through the cytoplasm and along the cortex toward the future apical domain. Our findings support an alternative polarity model where actin-directed trafficking asymmetrically inserts the nascent apical domain into the growing epithelial membrane to partition apicobasal membrane domains.
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Affiliation(s)
- Gholamali Jafari
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
| | - Liakot A. Khan
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
| | - Hongjie Zhang
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Edward Membreno
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
| | - Siyang Yan
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
| | - Graham Dempsey
- Chemistry and Chemical Biology Department, Harvard University, Cambridge, MA, USA
| | - Verena Gobel
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, MGHfC, Harvard Medical School, Boston, MA, USA
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6
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McDargh Z, Zhu T, Zhu H, O'Shaughnessy B. Actin turnover protects the cytokinetic contractile ring from structural instability. J Cell Sci 2023; 136:jcs259969. [PMID: 36052670 PMCID: PMC10660070 DOI: 10.1242/jcs.259969] [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: 02/25/2022] [Accepted: 08/17/2022] [Indexed: 11/20/2022] Open
Abstract
In common with other actomyosin contractile cellular machineries, actin turnover is required for normal function of the cytokinetic contractile ring. Cofilin is an actin-binding protein contributing to turnover by severing actin filaments, required for cytokinesis by many organisms. In fission yeast cofilin mutants, contractile rings suffer bridging instabilities in which segments of the ring peel away from the plasma membrane, forming straight bridges whose ends remain attached to the membrane. The origin of bridging instability is unclear. Here, we used molecularly explicit simulations of contractile rings to examine the role of cofilin. Simulations reproduced the experimentally observed cycles of bridging and reassembly during constriction, and the occurrence of bridging in ring segments with low density of the myosin II protein Myo2. The lack of cofilin severing produced ∼2-fold longer filaments and, consequently, ∼2-fold higher ring tensions. Simulations identified bridging as originating in the boosted ring tension, which increased centripetal forces that detached actin from Myo2, which was anchoring actin to the membrane. Thus, cofilin serves a critical role in cytokinesis by providing protection from bridging, the principal structural threat to contractile rings.
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Affiliation(s)
- Zachary McDargh
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
| | - Tianyi Zhu
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
| | - Hongkang Zhu
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
| | - Ben O'Shaughnessy
- Department of Chemical Engineering, Columbia University, New York, NY 10027, USA
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7
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Szikora S, Görög P, Mihály J. The Mechanisms of Thin Filament Assembly and Length Regulation in Muscles. Int J Mol Sci 2022; 23:5306. [PMID: 35628117 PMCID: PMC9140763 DOI: 10.3390/ijms23105306] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 02/01/2023] Open
Abstract
The actin containing tropomyosin and troponin decorated thin filaments form one of the crucial components of the contractile apparatus in muscles. The thin filaments are organized into densely packed lattices interdigitated with myosin-based thick filaments. The crossbridge interactions between these myofilaments drive muscle contraction, and the degree of myofilament overlap is a key factor of contractile force determination. As such, the optimal length of the thin filaments is critical for efficient activity, therefore, this parameter is precisely controlled according to the workload of a given muscle. Thin filament length is thought to be regulated by two major, but only partially understood mechanisms: it is set by (i) factors that mediate the assembly of filaments from monomers and catalyze their elongation, and (ii) by factors that specify their length and uniformity. Mutations affecting these factors can alter the length of thin filaments, and in human cases, many of them are linked to debilitating diseases such as nemaline myopathy and dilated cardiomyopathy.
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Affiliation(s)
- Szilárd Szikora
- Institute of Genetics, Biological Research Centre, H-6726 Szeged, Hungary;
| | - Péter Görög
- Institute of Genetics, Biological Research Centre, H-6726 Szeged, Hungary;
- Doctoral School of Multidisciplinary Medical Science, Faculty of Medicine, University of Szeged, H-6725 Szeged, Hungary
| | - József Mihály
- Institute of Genetics, Biological Research Centre, H-6726 Szeged, Hungary;
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary
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8
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Yao B, Donoughe S, Michaux J, Munro E. Modulating RhoA effectors induces transitions to oscillatory and more wavelike RhoA dynamics in C. elegans zygotes. Mol Biol Cell 2022; 33:ar58. [PMID: 35138935 PMCID: PMC9265151 DOI: 10.1091/mbc.e21-11-0542] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Pulsatile RhoA dynamics underlie a wide range of cell and tissue behaviors. The circuits that produce these dynamics in different cells share common architectures based on fast positive and delayed negative feedback through F-actin, but they can produce very different spatiotemporal patterns of RhoA activity. However, the underlying causes of this variation remain poorly understood. Here we asked how this variation could arise through modulation of actin network dynamics downstream of active RhoA in early C. elegans embryos. We find that perturbing two RhoA effectors - formin and anillin - induce transitions from non-recurrent focal pulses to either large noisy oscillatory pulses (formin depletion) or noisy oscillatory waves (anillin depletion). In both cases these transitions could be explained by changes in local F-actin levels and depletion dynamics, leading to changes in spatial and temporal patterns of RhoA inhibition. However, the underlying mechanisms for F-actin depletion are distinct, with different dependencies on myosin II activity. Thus, modulating actomyosin network dynamics could shape the spatiotemporal dynamics of RhoA activity for different physiological or morphogenetic functions. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].
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Affiliation(s)
- Baixue Yao
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637.,Committee on Cell Biology, University of Chicago, Chicago, IL 60637
| | - Seth Donoughe
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637
| | | | - Edwin Munro
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637.,Committee on Cell Biology, University of Chicago, Chicago, IL 60637.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, IL 60637.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL 60637
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9
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Imaging of Actin Cytoskeleton in the Nematode Caenorhabditis elegans. Methods Mol Biol 2021. [PMID: 34542852 DOI: 10.1007/978-1-0716-1661-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The nematode Caenorhabditis elegans is one of the major model organisms in cell and developmental biology. This organism is easy to culture in laboratories and suitable for microscopic investigation of the cytoskeleton. Because the worms are small and transparent, the actin cytoskeleton in many tissues and cells can be observed with appropriate visualization techniques without sectioning or dissection. This chapter describes the introduction to representative methods for imaging the actin cytoskeleton in C. elegans and a protocol for staining worms with fluorescent phalloidin.
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10
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Kučera O, Siahaan V, Janda D, Dijkstra SH, Pilátová E, Zatecka E, Diez S, Braun M, Lansky Z. Anillin propels myosin-independent constriction of actin rings. Nat Commun 2021; 12:4595. [PMID: 34321459 PMCID: PMC8319318 DOI: 10.1038/s41467-021-24474-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 06/21/2021] [Indexed: 02/07/2023] Open
Abstract
Constriction of the cytokinetic ring, a circular structure of actin filaments, is an essential step during cell division. Mechanical forces driving the constriction are attributed to myosin motor proteins, which slide actin filaments along each other. However, in multiple organisms, ring constriction has been reported to be myosin independent. How actin rings constrict in the absence of motor activity remains unclear. Here, we demonstrate that anillin, a non-motor actin crosslinker, indispensable during cytokinesis, autonomously propels the contractility of actin bundles. Anillin generates contractile forces of tens of pico-Newtons to maximise the lengths of overlaps between bundled actin filaments. The contractility is enhanced by actin disassembly. When multiple actin filaments are arranged into a ring, this contractility leads to ring constriction. Our results indicate that passive actin crosslinkers can substitute for the activity of molecular motors to generate contractile forces in a variety of actin networks, including the cytokinetic ring.
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Affiliation(s)
- Ondřej Kučera
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia ,grid.5583.b0000 0001 2299 8025Present Address: CytoMorpho Lab, Laboratoire Physiologie Cellulaire & Végétale, Institut de recherche interdisciplinaire de Grenoble, Commissariat à l’énergie atomique et aux énergies alternatives (CEA), Grenoble, France
| | - Valerie Siahaan
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Daniel Janda
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Sietske H. Dijkstra
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Eliška Pilátová
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Eva Zatecka
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Stefan Diez
- grid.4488.00000 0001 2111 7257B CUBE – Center for Molecular Bioengineering, TU Dresden, Dresden, Germany ,grid.419537.d0000 0001 2113 4567Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany ,grid.4488.00000 0001 2111 7257Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, Germany
| | - Marcus Braun
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
| | - Zdenek Lansky
- grid.418095.10000 0001 1015 3316Institute of Biotechnology, Czech Academy of Sciences, BIOCEV, Vestec, Prague West, Czechia
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11
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Balakrishnan M, Yu SF, Chin SM, Soffar DB, Windner SE, Goode BL, Baylies MK. Cofilin Loss in Drosophila Muscles Contributes to Muscle Weakness through Defective Sarcomerogenesis during Muscle Growth. Cell Rep 2021; 32:107893. [PMID: 32697999 PMCID: PMC7479987 DOI: 10.1016/j.celrep.2020.107893] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 02/23/2020] [Accepted: 06/19/2020] [Indexed: 12/20/2022] Open
Abstract
Sarcomeres, the fundamental contractile units of muscles, are conserved structures composed of actin thin filaments and myosin thick filaments. How sarcomeres are formed and maintained is not well understood. Here, we show that knockdown of Drosophila cofilin (DmCFL), an actin depolymerizing factor, disrupts both sarcomere structure and muscle function. The loss of DmCFL also results in the formation of sarcomeric protein aggregates and impairs sarcomere addition during growth. The activation of the proteasome delays muscle deterioration in our model. Furthermore, we investigate how a point mutation in CFL2 that causes nemaline myopathy (NM) in humans affects CFL function and leads to the muscle phenotypes observed in vivo. Our data provide significant insights to the role of CFLs during sarcomere formation, as well as mechanistic implications for disease progression in NM patients. How sarcomeres are added and maintained in a growing muscle cell is unclear. Balakrishnan et al. observed that DmCFL loss in growing muscles affects sarcomere size and addition through unregulated actin polymerization. This results in a collapse of sarcomere and muscle structure, formation of large protein aggregates, and muscle weakness.
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Affiliation(s)
- Mridula Balakrishnan
- Biochemistry & Structural Biology, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA; Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Shannon F Yu
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Samantha M Chin
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - David B Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Stefanie E Windner
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Mary K Baylies
- Biochemistry & Structural Biology, Cell & Developmental Biology, and Molecular Biology (BCMB) Program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA; Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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12
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Rust MB, Khudayberdiev S, Pelucchi S, Marcello E. CAPt'n of Actin Dynamics: Recent Advances in the Molecular, Developmental and Physiological Functions of Cyclase-Associated Protein (CAP). Front Cell Dev Biol 2020; 8:586631. [PMID: 33072768 PMCID: PMC7543520 DOI: 10.3389/fcell.2020.586631] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 08/26/2020] [Indexed: 12/11/2022] Open
Abstract
Cyclase-associated protein (CAP) has been discovered three decades ago in budding yeast as a protein that associates with the cyclic adenosine monophosphate (cAMP)-producing adenylyl cyclase and that suppresses a hyperactive RAS2 variant. Since that time, CAP has been identified in all eukaryotic species examined and it became evident that the activity in RAS-cAMP signaling is restricted to a limited number of species. Instead, its actin binding activity is conserved among eukaryotes and actin cytoskeleton regulation emerged as its primary function. However, for many years, the molecular functions as well as the developmental and physiological relevance of CAP remained unknown. In the present article, we will compile important recent progress on its molecular functions that identified CAP as a novel key regulator of actin dynamics, i.e., the spatiotemporally controlled assembly and disassembly of actin filaments (F-actin). These studies unraveled a cooperation with ADF/Cofilin and Twinfilin in F-actin disassembly, a nucleotide exchange activity on globular actin monomers (G-actin) that is required for F-actin assembly and an inhibitory function towards the F-actin assembly factor INF2. Moreover, by focusing on selected model organisms, we will review current literature on its developmental and physiological functions, and we will present studies implicating CAP in human pathologies. Together, this review article summarizes and discusses recent achievements in understanding the molecular, developmental and physiological functions of CAP, which led this protein emerge as a novel CAPt'n of actin dynamics.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, University of Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior, University of Marburg and Justus-Liebig-University Giessen, Giessen, Germany
| | - Sharof Khudayberdiev
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, Marburg, Germany
| | - Silvia Pelucchi
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
| | - Elena Marcello
- Department of Pharmacological and Biomolecular Sciences, University of Milan, Milan, Italy
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13
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Gordon KL, Zussman JW, Li X, Miller C, Sherwood DR. Stem cell niche exit in C. elegans via orientation and segregation of daughter cells by a cryptic cell outside the niche. eLife 2020; 9:e56383. [PMID: 32692313 PMCID: PMC7467730 DOI: 10.7554/elife.56383] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/17/2020] [Indexed: 12/17/2022] Open
Abstract
Stem cells reside in and rely upon their niche to maintain stemness but must balance self-renewal with the production of daughters that leave the niche to differentiate. We discovered a mechanism of stem cell niche exit in the canonical C. elegans distal tip cell (DTC) germ stem cell niche mediated by previously unobserved, thin, membranous protrusions of the adjacent somatic gonad cell pair (Sh1). A disproportionate number of germ cell divisions were observed at the DTC-Sh1 interface. Stem-like and differentiating cell fates segregated across this boundary. Spindles polarized, pairs of daughter cells oriented between the DTC and Sh1, and Sh1 grew over the Sh1-facing daughter. Impeding Sh1 growth by RNAi to cofilin and Arp2/3 perturbed the DTC-Sh1 interface, reduced germ cell proliferation, and shifted a differentiation marker. Because Sh1 membrane protrusions eluded detection for decades, it is possible that similar structures actively regulate niche exit in other systems.
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Affiliation(s)
- Kacy L Gordon
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - Jay W Zussman
- Department of Biology, Duke UniversityDurhamUnited States
| | - Xin Li
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - Camille Miller
- Department of Biology, The University of North Carolina at Chapel HillChapel HillUnited States
| | - David R Sherwood
- Department of Biology, Duke UniversityDurhamUnited States
- Regeneration Next, Duke UniversityDurhamUnited States
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14
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Tsuda Y, Yamanaka K, Toyoshima R, Ueda M, Masuda T, Misumi Y, Ogura T, Ando Y. Development of transgenic Caenorhabditis elegans expressing human transthyretin as a model for drug screening. Sci Rep 2018; 8:17884. [PMID: 30552363 PMCID: PMC6294829 DOI: 10.1038/s41598-018-36357-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/19/2018] [Indexed: 01/09/2023] Open
Abstract
Familial amyloid polyneuropathy is a hereditary systemic amyloidosis caused by a mutation in the transthyretin (TTR) gene. Amyloid deposits in tissues of patients contain not only full-length TTR but also C-terminal TTR fragments. However, in vivo models to evaluate the pathogenicity of TTR fragments have not yet been developed. Here, we generated transgenic Caenorhabditis elegans strains expressing several types of TTR fragments or full-length TTR fused to enhanced green fluorescent protein in the body wall muscle cells and analyzed the phenotypes of the worms. The transgenic strain expressing residues 81-127 of TTR, which included the β-strands F and H, formed aggregates and caused defective worm motility and a significantly shortened lifespan compared with other strains. These findings suggest that the C-terminal fragments of TTR may contribute to cytotoxicity of TTR amyloidosis in vivo. By using this C. elegans model system, we found that (-)-epigallocatechin-3-gallate, a major polyphenol in green tea, significantly inhibited the formation of aggregates, the defective motility, and the shortened lifespan caused by residues 81-127 of TTR. These results suggest that our newly developed C. elegans model system will be useful for in vivo pathological analyses of TTR amyloidosis as well as drug screening.
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Affiliation(s)
- Yukimoto Tsuda
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Kunitoshi Yamanaka
- Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan.
| | - Risa Toyoshima
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Mitsuharu Ueda
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan.
| | - Teruaki Masuda
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Yohei Misumi
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
| | - Teru Ogura
- Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan
| | - Yukio Ando
- Department of Neurology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Chuo-ku, Kumamoto, 860-8556, Japan
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Ueda EI, Kashiwazaki J, Inoué S, Mabuchi I. Fission yeast Adf1 is necessary for reassembly of actin filaments into the contractile ring during cytokinesis. Biochem Biophys Res Commun 2018; 506:330-338. [DOI: 10.1016/j.bbrc.2018.07.156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/31/2018] [Indexed: 01/27/2023]
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16
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Wirshing ACE, Cram EJ. Spectrin regulates cell contractility through production and maintenance of actin bundles in the Caenorhabditis elegans spermatheca. Mol Biol Cell 2018; 29:2433-2449. [PMID: 30091661 PMCID: PMC6233056 DOI: 10.1091/mbc.e18-06-0347] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Disruption to the contractility of cells, including smooth muscle cells of the cardiovascular system and myoepithelial cells of the glandular epithelium, contributes to the pathophysiology of contractile tissue diseases, including asthma, hypertension, and primary Sjögren's syndrome. Cell contractility is determined by myosin activity and actomyosin network organization and is mediated by hundreds of protein-protein interactions, many directly involving actin. Here we use a candidate RNA interference screen of more than 100 Caenorhabditis elegans genes with predicted actin-binding and regulatory domains to identify genes that contribute to the contractility of the somatic gonad. We identify the spectrin cytoskeleton composed of SPC-1/α-spectrin, UNC-70/β-spectrin, and SMA-1/β heavy-spectrin as required for contractility and actin organization in the myoepithelial cells of the C. elegans spermatheca. We use imaging of fixed and live animals as well as tissue- and developmental-stage-specific disruption of the spectrin cytoskeleton to show that spectrin regulates the production of prominent central actin bundles and is required for maintenance of central actin bundles throughout successive rounds of stretch and contraction. We conclude that the spectrin cytoskeleton contributes to spermathecal contractility by promoting maintenance of the robust actomyosin bundles that drive contraction.
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Affiliation(s)
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA 02115
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Kaletsky R, Yao V, Williams A, Runnels AM, Tadych A, Zhou S, Troyanskaya OG, Murphy CT. Transcriptome analysis of adult Caenorhabditis elegans cells reveals tissue-specific gene and isoform expression. PLoS Genet 2018; 14:e1007559. [PMID: 30096138 PMCID: PMC6105014 DOI: 10.1371/journal.pgen.1007559] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 08/22/2018] [Accepted: 07/13/2018] [Indexed: 12/19/2022] Open
Abstract
The biology and behavior of adults differ substantially from those of developing animals, and cell-specific information is critical for deciphering the biology of multicellular animals. Thus, adult tissue-specific transcriptomic data are critical for understanding molecular mechanisms that control their phenotypes. We used adult cell-specific isolation to identify the transcriptomes of C. elegans' four major tissues (or "tissue-ome"), identifying ubiquitously expressed and tissue-specific "enriched" genes. These data newly reveal the hypodermis' metabolic character, suggest potential worm-human tissue orthologies, and identify tissue-specific changes in the Insulin/IGF-1 signaling pathway. Tissue-specific alternative splicing analysis identified a large set of collagen isoforms. Finally, we developed a machine learning-based prediction tool for 76 sub-tissue cell types, which we used to predict cellular expression differences in IIS/FOXO signaling, stage-specific TGF-β activity, and basal vs. memory-induced CREB transcription. Together, these data provide a rich resource for understanding the biology governing multicellular adult animals.
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Affiliation(s)
- Rachel Kaletsky
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Victoria Yao
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
| | - April Williams
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Alexi M. Runnels
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Alicja Tadych
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Shiyi Zhou
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
| | - Olga G. Troyanskaya
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
- Department of Computer Science, Princeton University, Princeton, New Jersey, United States of America
- Flatiron Institute, Simons Foundation, New York, New York, United States of America
| | - Coleen T. Murphy
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States of America
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Raiders SA, Eastwood MD, Bacher M, Priess JR. Binucleate germ cells in Caenorhabditis elegans are removed by physiological apoptosis. PLoS Genet 2018; 14:e1007417. [PMID: 30024879 PMCID: PMC6053125 DOI: 10.1371/journal.pgen.1007417] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/15/2018] [Indexed: 12/27/2022] Open
Abstract
Cell death plays a major role during C. elegans oogenesis, where over half of the oogenic germ cells die in a process termed physiological apoptosis. How germ cells are selected for physiological apoptosis, or instead become oocytes, is not understood. Most oocytes produce viable embryos when apoptosis is blocked, suggesting that physiological apoptosis does not function to cull defective germ cells. Instead, cells targeted for apoptosis may function as nurse cells; the germline is syncytial, and all germ cells appear to contribute cytoplasm to developing oocytes. C. elegans has been a leading model for the genetics and molecular biology of apoptosis and phagocytosis, but comparatively few studies have examined the cell biology of apoptotic cells. We used live imaging to identify and examine pre-apoptotic germ cells in the adult gonad. After initiating apoptosis, germ cells selectively export their mitochondria into the shared pool of syncytial cytoplasm; this transport appears to use the microtubule motor kinesin. The apoptotic cells then shrink as they expel most of their remaining cytoplasm, and close off from the syncytium. Shortly thereafter the apoptotic cells restructure their microtubule and actin cytoskeletons, possibly to maintain cell integrity; the microtubules form a novel, cortical array of stabilized microtubules, and actin and cofilin organize into giant cofilin-actin rods. We discovered that some apoptotic germ cells are binucleate; the binucleate germ cells can develop into binucleate oocytes in apoptosis-defective strains, and appear capable of producing triploid offspring. Our results suggest that the nuclear layer of the germline syncytium becomes folded during mitosis and growth, and that binucleate cells arise as the layer unfolds or everts; all of the binucleate cells are subsequently removed by apoptosis. These results show that physiological apoptosis targets at least two distinct populations of germ cells, and that the apoptosis machinery efficiently recognizes cells with two nuclei. Many germ cells die by apoptosis during the development of animal oocytes, including more than half of all germ cells in the model system C. elegans. How individual germ cells are selected for apoptosis, or survival, is not known. Here we study the cell biology of apoptosis. The C. elegans gonad is a syncytium, with nearly 1000 germ “cells” connected to a shared, core cytoplasm. Once apoptosis is initiated, germ cells selectively transport their mitochondria into the gonad core, apparently using the microtubule motor protein kinesin. The apoptotic cells next constrict, expelling most of their remaining cytoplasm into the core, and close off from the gonad core. The microtubule and actin cytoskeletons are remodeled and stabilized, presumably to maintain the integrity of the dying cell. The apoptotic cells form giant cofilin-actin rods, similar to rods described in stressed cultured cells and in human myopathies and neuropathies such as Alzheimer’s and Huntington’s disease. We show that some germ cells are binucleate; these cells appear to form during germline morphogenesis, and are removed by apoptosis. These results demonstrate heterogeneity between oogenic germ cells, and show that the apoptosis machinery efficiently recognizes and removes cells with two nuclei.
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Affiliation(s)
- Stephan A. Raiders
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Michael D. Eastwood
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Meghan Bacher
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - James R. Priess
- Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington, United States of America
- Department of Biology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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Naskar S, Panda AK, Kumaran V, Mehta B, Basu B. Controlled Shear Flow Directs Osteogenesis on UHMWPE-Based Hybrid Nanobiocomposites in a Custom-Designed PMMA Microfluidic Device. ACS APPLIED BIO MATERIALS 2018; 1:414-435. [DOI: 10.1021/acsabm.8b00147] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Sharmistha Naskar
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Asish Kumar Panda
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
| | - Viswanathan Kumaran
- Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Bhupesh Mehta
- Department of Biophysics, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Bikramjit Basu
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore 560012, India
- Laboratory for Biomaterials, Materials Research Centre, Indian Institute of Science, Bangalore 560012, India
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20
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King CD, Singh D, Holden K, Govan AB, Keith SA, Ghazi A, Robinson RA. Proteomic identification of virulence-related factors in young and aging C. elegans infected with Pseudomonas aeruginosa. J Proteomics 2018; 181:92-103. [DOI: 10.1016/j.jprot.2018.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 03/26/2018] [Accepted: 04/09/2018] [Indexed: 12/16/2022]
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21
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Hu J, Shi Y, Xia M, Liu Z, Zhang R, Luo H, Zhang T, Yang Z, Yuan B. WDR1-regulated actin dynamics is required for outflow tract and right ventricle development. Dev Biol 2018; 438:124-137. [PMID: 29654745 DOI: 10.1016/j.ydbio.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 04/05/2018] [Accepted: 04/08/2018] [Indexed: 10/17/2022]
Abstract
Outflow tract (OFT) anomalies account for about 30% of human congenital heart defects detected at birth. The second heart field (SHF) progenitors contribute to OFT and right ventricle (RV) development, but the process largely remains unknown. WDR1 (WD-repeat domain 1) is a major co-factor of actin depolymerizing factor (ADF)/cofilin that actively disassembles ADF/cofilin-bound actin filaments. Its function in embryonic heart development has been unknown. Using Wdr1 floxed mice and Nkx2.5-Cre, we deleted Wdr1 in embryonic heart (Wdr1F/F;Nkx2.5-Cre) and found that these mice exhibited embryonic lethality, and hypoplasia of OFT and RV. To investigate the role of WDR1 in OFT and RV development, we generated SHF progenitors-specific Wdr1 deletion mice (shfKO). shfKO mice began to die at embryonic day 11.5 (E11.5), and displayed decreased size of the proximal OFT and RV at E10.5. In shfKO embryos, neither the number of SHF cells deployment to OFT nor cell proliferation and the cell number were changed, whereas the cellular organization and myofibrillar assembly of cardiomyocytes were severely disrupted. In the proximal OFT and RV of both shfKO and Wdr1F/F;Nkx2.5-Cre embryos, cardiomyocytes were dissociated from the outer compact myocardial layer and loosely and disorderly arranged into multilayered myocardium. Our results demonstrate that WDR1 is indispensable for normal OFT and RV development, and suggest that WDR1-mediated actin dynamics functions in controlling the size of OFT and RV, which might through regulating the spatial arrangement of cardiomyocytes.
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Affiliation(s)
- Jisheng Hu
- Biomedical Research Institute, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Yingchao Shi
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing 210061, China
| | - Meng Xia
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing 210061, China
| | - Zhongying Liu
- Biomedical Research Institute, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Ruirui Zhang
- Biomedical Research Institute, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Hongmei Luo
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing 210061, China
| | - Tongcun Zhang
- Biomedical Research Institute, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China
| | - Zhongzhou Yang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing Biomedical Research Institute, Nanjing University, Nanjing 210061, China.
| | - Baiyin Yuan
- Biomedical Research Institute, College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, Hubei Province 430065, China.
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Wani S, Kuroyanagi H. An emerging model organism Caenorhabditis elegans for alternative pre-mRNA processing in vivo. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28703462 DOI: 10.1002/wrna.1428] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/02/2017] [Accepted: 05/02/2017] [Indexed: 12/13/2022]
Abstract
A nematode Caenorhabditis elegans is an intron-rich organism and up to 25% of its pre-mRNAs are estimated to be alternatively processed. Its compact genomic organization enables construction of fluorescence splicing reporters with intact genomic sequences and visualization of alternative processing patterns of interest in the transparent living animals with single-cell resolution. Genetic analysis with the reporter worms facilitated identification of trans-acting factors and cis-acting elements, which are highly conserved in mammals. Analysis of unspliced and partially spliced pre-mRNAs in vivo raised models for alternative splicing regulation relying on specific order of intron excision. RNA-seq analysis of splicing factor mutants and CLIP-seq analysis of the factors allow global search for target genes in the whole animal. An mRNA surveillance system is not essential for its viability or fertility, allowing analysis of unproductively spliced noncoding mRNAs. These features offer C. elegans as an ideal model organism for elucidating alternative pre-mRNA processing mechanisms in vivo. Examples of isoform-specific functions of alternatively processed genes are summarized. WIREs RNA 2017, 8:e1428. doi: 10.1002/wrna.1428 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Shotaro Wani
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidehito Kuroyanagi
- Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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Ca 2+ Signalling and Membrane Dynamics During Cytokinesis in Animal Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:389-412. [PMID: 29594869 DOI: 10.1007/978-3-319-55858-5_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
Interest in the role of Ca2+ signalling as a possible regulator of the combinatorial processes that result in the separation of the daughter cells during cytokinesis, extend back almost a 100 years. One of the key processes required for the successful completion of cytokinesis in animal cells (especially in the large holoblastically and meroblastically dividing embryonic cells of a number of amphibian and fish species), is the dynamic remodelling of the plasma membrane. Ca2+ signalling was subsequently demonstrated to regulate various different aspects of cytokinesis in animal cells, and so here we focus specifically on the role of Ca2+ signalling in the remodelling of the plasma membrane. We begin by providing a brief history of the animal models used and the research accomplished by the early twentieth century investigators, with regards to this aspect of animal cell cytokinesis. We then review the most recent progress made (i.e., in the last 10 years), which has significantly advanced our current understanding on the role of cytokinetic Ca2+ signalling in membrane remodelling. To this end, we initially summarize what is currently known about the Ca2+ transients generated during animal cell cytokinesis, and then we describe the latest findings regarding the source of Ca2+ generating these transients. Finally, we review the current evidence about the possible targets of the different cytokinetic Ca2+ transients with a particular emphasis on those that either directly or indirectly affect plasma membrane dynamics. With regards to the latter, we discuss the possible role of the early Ca2+ signalling events in the deformation of the plasma membrane at the start of cytokinesis (i.e., during furrow positioning), as well as the role of the subsequent Ca2+ signals in the trafficking and fusion of vesicles, which help to remodel the plasma membrane during the final stages of cell division. As it is becoming clear that each of the cytokinetic Ca2+ transients might have multiple, integrated targets, deciphering the precise role of each transient represents a significant (and ongoing) challenge.
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Nomura K, Hayakawa K, Tatsumi H, Ono S. Actin-interacting Protein 1 Promotes Disassembly of Actin-depolymerizing Factor/Cofilin-bound Actin Filaments in a pH-dependent Manner. J Biol Chem 2016; 291:5146-56. [PMID: 26747606 DOI: 10.1074/jbc.m115.713495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Indexed: 02/02/2023] Open
Abstract
Actin-interacting protein 1 (AIP1) is a conserved WD repeat protein that promotes disassembly of actin filaments when actin-depolymerizing factor (ADF)/cofilin is present. Although AIP1 is known to be essential for a number of cellular events involving dynamic rearrangement of the actin cytoskeleton, the regulatory mechanism of the function of AIP1 is unknown. In this study, we report that two AIP1 isoforms from the nematode Caenorhabditis elegans, known as UNC-78 and AIPL-1, are pH-sensitive in enhancement of actin filament disassembly. Both AIP1 isoforms only weakly enhance disassembly of ADF/cofilin-bound actin filaments at an acidic pH but show stronger disassembly activity at neutral and basic pH values. However, a severing-defective mutant of UNC-78 shows pH-insensitive binding to ADF/cofilin-decorated actin filaments, suggesting that the process of filament severing or disassembly, but not filament binding, is pH-dependent. His-60 of AIP1 is located near the predicted binding surface for the ADF/cofilin-actin complex, and an H60K mutation of AIP1 partially impairs its pH sensitivity, suggesting that His-60 is involved in the pH sensor for AIP1. These biochemical results suggest that pH-dependent changes in AIP1 activity might be a novel regulatory mechanism of actin filament dynamics.
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Affiliation(s)
- Kazumi Nomura
- From the Departments of Pathology and Cell Biology, Emory University, Atlanta, Georgia 30322
| | | | - Hitoshi Tatsumi
- Department of Physiology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan, and the Department of Applied Biosciences, Kanazawa Institute of Technology, Kanazawa 924-0838, Japan
| | - Shoichiro Ono
- From the Departments of Pathology and Cell Biology, Emory University, Atlanta, Georgia 30322,
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Gracida X, Norris AD, Calarco JA. Regulation of Tissue-Specific Alternative Splicing: C. elegans as a Model System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 907:229-61. [DOI: 10.1007/978-3-319-29073-7_10] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Ono S. Regulation of structure and function of sarcomeric actin filaments in striated muscle of the nematode Caenorhabditis elegans. Anat Rec (Hoboken) 2015; 297:1548-59. [PMID: 25125169 DOI: 10.1002/ar.22965] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/26/2014] [Accepted: 02/26/2014] [Indexed: 02/01/2023]
Abstract
The nematode Caenorhabditis elegans has been used as a valuable system to study structure and function of striated muscle. The body wall muscle of C. elegans is obliquely striated muscle with highly organized sarcomeric assembly of actin, myosin, and other accessory proteins. Genetic and molecular biological studies in C. elegans have identified a number of genes encoding structural and regulatory components for the muscle contractile apparatuses, and many of them have counterparts in mammalian cardiac and skeletal muscles or striated muscles in other invertebrates. Applicability of genetics, cell biology, and biochemistry has made C. elegans an excellent system to study mechanisms of muscle contractility and assembly and maintenance of myofibrils. This review focuses on the regulatory mechanisms of structure and function of actin filaments in the C. elegans body wall muscle. Sarcomeric actin filaments in C. elegans muscle are associated with the troponin-tropomyosin system that regulates the actin-myosin interaction. Proteins that bind to the side and ends of actin filaments support ordered assembly of thin filaments. Furthermore, regulators of actin dynamics play important roles in initial assembly, growth, and maintenance of sarcomeres. The knowledge acquired in C. elegans can serve as bases to understand the basic mechanisms of muscle structure and function.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia; Department of Cell Biology, Emory University, Atlanta, Georgia
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27
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Solution structures and dynamics of ADF/cofilins UNC-60A and UNC-60B from Caenorhabditis elegans. Biochem J 2015; 465:63-78. [PMID: 25279657 DOI: 10.1042/bj20140923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The nematode Caenorhabditis elegans has two ADF (actin-depolymerizing factor)/cofilin isoforms, UNC-60A and UNC-60B, which are expressed by the unc60 gene by alternative splicing. UNC-60A has higher activity to cause net depolymerization, and to inhibit polymerization, than UNC-60B. UNC-60B, on the other hand, shows much stronger severing activity than UNC-60A. To understand the structural basis of their functional differences, we have determined the solution structures of UNC-60A and UNC-60B proteins and characterized their backbone dynamics. Both UNC-60A and UNC-60B show a conserved ADF/cofilin fold. The G-actin (globular actin)-binding regions of the two proteins are structurally and dynamically conserved. Accordingly, UNC-60A and UNC-60B individually bind to rabbit muscle ADP-G-actin with high affinities, with Kd values of 32.25 nM and 8.62 nM respectively. The primary differences between these strong and weak severing proteins were observed in the orientation and dynamics of the F-actin (filamentous actin)-binding loop (F-loop). In the strong severing activity isoform UNC-60B, the orientation of the F-loop was towards the recently identified F-loop-binding region on F-actin, and the F-loop was relatively more flexible with 14 residues showing motions on a nanosecond-picosecond timescale. In contrast, in the weak severing protein isoform UNC-60A, the orientation of the F-loop was away from the F-loop-binding region and inclined towards its own C-terminal and strand β6. It was also relatively less flexible with only five residues showing motions on a nanosecond-picosecond timescale. These differences in structure and dynamics seem to directly correlate with the differential F-actin site-binding and severing properties of UNC-60A and UNC-60B, and other related ADF/cofilin proteins.
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Grego-Bessa J, Hildebrand J, Anderson KV. Morphogenesis of the mouse neural plate depends on distinct roles of cofilin 1 in apical and basal epithelial domains. Development 2015; 142:1305-14. [PMID: 25742799 DOI: 10.1242/dev.115493] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The genetic control of mammalian epithelial polarity and dynamics can be studied in vivo at cellular resolution during morphogenesis of the mouse neural tube. The mouse neural plate is a simple epithelium that is transformed into a columnar pseudostratified tube over the course of ∼ 24 h. Apical F-actin is known to be important for neural tube closure, but the precise roles of actin dynamics in the neural epithelium are not known. To determine how the organization of the neural epithelium and neural tube closure are affected when actin dynamics are blocked, we examined the cellular basis of the neural tube closure defect in mouse mutants that lack the actin-severing protein cofilin 1 (CFL1). Although apical localization of the adherens junctions, the Par complex, the Crumbs complex and SHROOM3 is normal in the mutants, CFL1 has at least two distinct functions in the apical and basal domains of the neural plate. Apically, in the absence of CFL1 myosin light chain does not become phosphorylated, indicating that CFL1 is required for the activation of apical actomyosin required for neural tube closure. On the basal side of the neural plate, loss of CFL1 has the opposite effect on myosin: excess F-actin and myosin accumulate and the ectopic myosin light chain is phosphorylated. The basal accumulation of F-actin is associated with the assembly of ectopic basal tight junctions and focal disruptions of the basement membrane, which eventually lead to a breakdown of epithelial organization.
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Affiliation(s)
- Joaquim Grego-Bessa
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
| | - Jeffrey Hildebrand
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Kathryn V Anderson
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065, USA
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Kremneva E, Makkonen MH, Skwarek-Maruszewska A, Gateva G, Michelot A, Dominguez R, Lappalainen P. Cofilin-2 controls actin filament length in muscle sarcomeres. Dev Cell 2015; 31:215-26. [PMID: 25373779 DOI: 10.1016/j.devcel.2014.09.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 07/03/2014] [Accepted: 09/03/2014] [Indexed: 01/26/2023]
Abstract
ADF/cofilins drive cytoskeletal dynamics by promoting the disassembly of "aged" ADP-actin filaments. Mammals express several ADF/cofilin isoforms, but their specific biochemical activities and cellular functions have not been studied in detail. Here, we demonstrate that the muscle-specific isoform cofilin-2 promotes actin filament disassembly in sarcomeres to control the precise length of thin filaments in the contractile apparatus. In contrast to other isoforms, cofilin-2 efficiently binds and disassembles both ADP- and ATP/ADP-Pi-actin filaments. We mapped surface-exposed cofilin-2-specific residues required for ATP-actin binding and propose that these residues function as an "actin nucleotide-state sensor" among ADF/cofilins. The results suggest that cofilin-2 evolved specific biochemical and cellular properties that allow it to control actin dynamics in sarcomeres, where filament pointed ends may contain a mixture of ADP- and ATP/ADP-Pi-actin subunits. Our findings also offer a rationale for why cofilin-2 mutations in humans lead to myopathies.
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Affiliation(s)
- Elena Kremneva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Maarit H Makkonen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | | | - Gergana Gateva
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | - Alphee Michelot
- Laboratoire de Physiologie Cellulaire et Végétale, Institut de Recherches en Technologies et Sciences pour le Vivant, iRTSV, CNRS/CEA/INRA/UJF, 38054 Grenoble, France
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland.
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Abstract
The essential neurotransmitter acetylcholine functions throughout the animal kingdom. In Caenorhabditis elegans, the acetylcholine biosynthetic enzyme [choline acetyltransferase (ChAT)] and vesicular transporter [vesicular acetylcholine transporter (VAChT)] are encoded by the cha-1 and unc-17 genes, respectively. These two genes compose a single complex locus in which the unc-17 gene is nested within the first intron of cha-1, and the two gene products arise from a common pre-messenger RNA (pre-mRNA) by alternative splicing. This genomic organization, known as the cholinergic gene locus (CGL), is conserved throughout the animal kingdom, suggesting that the structure is important for the regulation and function of these genes. However, very little is known about CGL regulation in any species. We now report the identification of an unusual type of splicing regulation in the CGL of C. elegans, mediated by two pairs of complementary sequence elements within the locus. We show that both pairs of elements are required for efficient splicing to the distal acceptor, and we also demonstrate that proper distal splicing depends more on sequence complementarity within each pair of elements than on the sequences themselves. We propose that these sequence elements are able to form stem-loop structures in the pre-mRNA; such structures would favor specific splicing alternatives and thus regulate CGL splicing. We have identified complementary elements at comparable locations in the genomes of representative species of other animal phyla; we suggest that this unusual regulatory mechanism may be a general feature of CGLs.
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Etheridge T, Rahman M, Gaffney CJ, Shaw D, Shephard F, Magudia J, Solomon DE, Milne T, Blawzdziewicz J, Constantin-Teodosiu D, Greenhaff PL, Vanapalli SA, Szewczyk NJ. The integrin-adhesome is required to maintain muscle structure, mitochondrial ATP production, and movement forces in Caenorhabditis elegans. FASEB J 2014; 29:1235-46. [PMID: 25491313 PMCID: PMC4396603 DOI: 10.1096/fj.14-259119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 11/11/2014] [Indexed: 01/19/2023]
Abstract
The integrin-adhesome network, which contains >150 proteins, is mechano-transducing and located at discreet positions along the cell-cell and cell-extracellular matrix interface. A small subset of the integrin-adhesome is known to maintain normal muscle morphology. However, the importance of the entire adhesome for muscle structure and function is unknown. We used RNA interference to knock down 113 putative Caenorhabditis elegans homologs constituting most of the mammalian adhesome and 48 proteins known to localize to attachment sites in C. elegans muscle. In both cases, we found >90% of components were required for normal muscle mitochondrial structure and/or proteostasis vs. empty vector controls. Approximately half of these, mainly proteins that physically interact with each other, were also required for normal sarcomere and/or adhesome structure. Next we confirmed that the dystrophy observed in adhesome mutants associates with impaired maximal mitochondrial ATP production (P < 0.01), as well as reduced probability distribution of muscle movement forces compared with wild-type animals. Our results show that the integrin-adhesome network as a whole is required for maintaining both muscle structure and function and extend the current understanding of the full complexities of the functional adhesome in vivo.—Etheridge, T., Rahman, M., Gaffney, C. J., Shaw, D., Shephard, F., Magudia, J., Solomon, D. E., Milne, T., Blawzdziewicz, J., Constantin-Teodosiu, D., Greenhaff, P. L., Vanapalli, S. A., Szewczyk, N. J. The integrin-adhesome is required to maintain muscle structure, mitochondrial ATP production, and movement forces in Caenorhabditis elegans.
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Affiliation(s)
- Timothy Etheridge
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Mizanur Rahman
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Christopher J Gaffney
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Debra Shaw
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Freya Shephard
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Jignesh Magudia
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Deepak E Solomon
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Thomas Milne
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Jerzy Blawzdziewicz
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Dumitru Constantin-Teodosiu
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Paul L Greenhaff
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Siva A Vanapalli
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
| | - Nathaniel J Szewczyk
- *Department of Sport and Health Science, College of Life and Environmental Sciences, and College of Engineering, Mathematics and Physical Science, University of Exeter, Exeter, United Kingdom; Departments of Chemical Engineering and Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA; Medical Research Council/Arthritis Research UK Centre for Musculoskeletal Ageing Research, Schools of Life Sciences and Medicine, University of Nottingham, Nottingham, United Kingdom; and School of Veterinary Medicine and Science, University of Nottingham, Leicestershire, United Kingdom
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32
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Regulation of synaptic extracellular matrix composition is critical for proper synapse morphology. J Neurosci 2014; 34:12678-89. [PMID: 25232106 DOI: 10.1523/jneurosci.1183-14.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Synapses are surrounded by a layer of extracellular matrix (ECM), which is instrumental for their development and maintenance. ECM composition is dynamically controlled by proteases, but how the precise composition of the ECM affects synaptic morphology is largely unknown. Through an unbiased forward genetic screen, we found that Caenorhabditis elegans gon-1, a conserved extracellular ADAMTS protease, is required for maintaining proper synaptic morphology at the neuromuscular junction. In gon-1 mutants, once synapse formation is complete, motor neuron presynaptic varicosities develop into large bulbous protrusions that contain synaptic vesicles and active zone proteins. A concomitant overgrowth of postsynaptic muscle membrane is found in close apposition to presynaptic axonal protrusions. Mutations in the muscle-specific, actin-severing protein cofilin (unc-60) suppress the axon phenotype, suggesting that muscle outgrowth is necessary for presynaptic protrusions. gon-1 mutants can also be suppressed by loss of the ECM components collagen IV (EMB-9) and fibulin (FBL-1). We propose that GON-1 regulates a developmental switch out of an initial "pro-growth" phase during which muscle arms grow out and form synapses with motor neuron axons. We postulate that this switch involves degradation or reorganization of collagen IV (EMB-9), whereas FBL-1 opposes GON-1 by stabilizing EMB-9. Our results describe a mechanism for regulating synaptic ECM composition and reveal the importance of precise ECM composition for neuronal morphology and synapse integrity.
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33
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Ono S. The role of cyclase-associated protein in regulating actin filament dynamics - more than a monomer-sequestration factor. J Cell Sci 2014; 126:3249-58. [PMID: 23908377 DOI: 10.1242/jcs.128231] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is fundamental to a number of cell biological events. A variety of actin-regulatory proteins modulate polymerization and depolymerization of actin and contribute to actin cytoskeletal reorganization. Cyclase-associated protein (CAP) is a conserved actin-monomer-binding protein that has been studied for over 20 years. Early studies have shown that CAP sequesters actin monomers; recent studies, however, have revealed more active roles of CAP in actin filament dynamics. CAP enhances the recharging of actin monomers with ATP antagonistically to ADF/cofilin, and also promotes the severing of actin filaments in cooperation with ADF/cofilin. Self-oligomerization and binding to other proteins regulate activities and localization of CAP. CAP has crucial roles in cell signaling, development, vesicle trafficking, cell migration and muscle sarcomere assembly. This Commentary discusses the recent advances in our understanding of the functions of CAP and its implications as an important regulator of actin cytoskeletal dynamics, which are involved in various cellular activities.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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34
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Hagedorn EJ, Kelley LC, Naegeli KM, Wang Z, Chi Q, Sherwood DR. ADF/cofilin promotes invadopodial membrane recycling during cell invasion in vivo. ACTA ACUST UNITED AC 2014; 204:1209-18. [PMID: 24662568 PMCID: PMC3971745 DOI: 10.1083/jcb.201312098] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Localized F-actin disassembly by ADF/cofilin drives invadopodial membrane recycling through endolysosomes, which promotes efficient cell transmigration through the basement membrane. Invadopodia are protrusive, F-actin–driven membrane structures that are thought to mediate basement membrane transmigration during development and tumor dissemination. An understanding of the mechanisms regulating invadopodia has been hindered by the difficulty of examining these dynamic structures in native environments. Using an RNAi screen and live-cell imaging of anchor cell (AC) invasion in Caenorhabditis elegans, we have identified UNC-60A (ADF/cofilin) as an essential regulator of invadopodia. UNC-60A localizes to AC invadopodia, and its loss resulted in a dramatic slowing of F-actin dynamics and an inability to breach basement membrane. Optical highlighting indicated that UNC-60A disassembles actin filaments at invadopodia. Surprisingly, loss of unc-60a led to the accumulation of invadopodial membrane and associated components within the endolysosomal compartment. Photobleaching experiments revealed that during normal invasion the invadopodial membrane undergoes rapid recycling through the endolysosome. Together, these results identify the invadopodial membrane as a specialized compartment whose recycling to form dynamic, functional invadopodia is dependent on localized F-actin disassembly by ADF/cofilin.
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35
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Mendes Pinto I, Rubinstein B, Li R. Force to divide: structural and mechanical requirements for actomyosin ring contraction. Biophys J 2014; 105:547-54. [PMID: 23931302 DOI: 10.1016/j.bpj.2013.06.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 06/14/2013] [Accepted: 06/24/2013] [Indexed: 10/26/2022] Open
Abstract
One of the unresolved questions in the field of cell division is how the actomyosin cytoskeleton remains structurally organized while generating the contractile force to divide one cell into two. In analogy to the actomyosin-based force production mechanism in striated muscle, it was originally proposed that contractile stress in the actomyosin ring is generated via a sliding filament mechanism within an organized sarcomere-like array. However, over the last 30 years, ultrastructural and functional studies have noted important distinctions between cytokinetic structures in dividing cells and muscle sarcomeres. Myosin-II motor activity is not always required, and there is evidence that actin depolymerization contributes to contraction. In this Review, the architecture and contractile dynamics of the actomyosin ring at the cell division plane will be discussed. We will report the interdisciplinary advances in the field as well as their integration into a mechanistic understanding of contraction in cell division and in other biological processes that rely on an actomyosin-based force-generating system.
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36
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An equatorial contractile mechanism drives cell elongation but not cell division. PLoS Biol 2014; 12:e1001781. [PMID: 24503569 PMCID: PMC3913557 DOI: 10.1371/journal.pbio.1001781] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 12/20/2013] [Indexed: 11/19/2022] Open
Abstract
A cytokinesis-like contractile mechanism is co-opted in a different developmental scenario to achieve cell elongation instead of cell division in Ciona intestinalis. Cell shape changes and proliferation are two fundamental strategies for morphogenesis in animal development. During embryogenesis of the simple chordate Ciona intestinalis, elongation of individual notochord cells constitutes a crucial stage of notochord growth, which contributes to the establishment of the larval body plan. The mechanism of cell elongation is elusive. Here we show that although notochord cells do not divide, they use a cytokinesis-like actomyosin mechanism to drive cell elongation. The actomyosin network forming at the equator of each notochord cell includes phosphorylated myosin regulatory light chain, α-actinin, cofilin, tropomyosin, and talin. We demonstrate that cofilin and α-actinin are two crucial components for cell elongation. Cortical flow contributes to the assembly of the actomyosin ring. Similar to cytokinetic cells, membrane blebs that cause local contractions form at the basal cortex next to the equator and participate in force generation. We present a model in which the cooperation of equatorial actomyosin ring-based constriction and bleb-associated contractions at the basal cortex promotes cell elongation. Our results demonstrate that a cytokinesis-like contractile mechanism is co-opted in a completely different developmental scenario to achieve cell shape change instead of cell division. We discuss the occurrences of actomyosin rings aside from cell division, suggesting that circumferential contraction is an evolutionally conserved mechanism to drive cell or tissue elongation. The actomyosin cytoskeleton is the primary force that drives cell shape changes. These fibers are organized in elaborate structures that form sarcomeres in the muscle and the contractile ring during cytokinesis. In cytokinesis, the establishment of an equatorial actomyosin ring is preceded and regulated by many cell cycle events, and the ring itself is a complex and dynamic structure. Here we report the presence of an equatorial circumferential actomyosin structure with remarkable similarities to the cytokinetic ring formed in postmitotic notochord cells of sea squirt Ciona intestinalis. The notochord is a transient rod-like structure found in all embryos that belong to the phylum Chordata, and in Ciona, a simple chordate, it consists of only 40 cylindrical cells arranged in a single file, which elongate individually during development. Our study shows that the activity of the equatorial actomyosin ring is required for the elongation of the notochord cells. We also find that cortical flow contributes significantly to the formation of the ring at the equator. Similar to cytokinetic cells, we observe the formation of membrane blebs outside the equatorial region. Our analyses suggest that cooperation of actomyosin ring-based circumferential constriction and bleb-associated contractions drive cell elongation in Ciona. We conclude that cells can utilize a cytokinesis-like force generation mechanism to promote cell shape change instead of cell division.
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37
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Ono K, Ono S. Two actin-interacting protein 1 isoforms function redundantly in the somatic gonad and are essential for reproduction in Caenorhabditis elegans. Cytoskeleton (Hoboken) 2013; 71:36-45. [PMID: 24130131 DOI: 10.1002/cm.21152] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 09/17/2013] [Accepted: 10/10/2013] [Indexed: 11/11/2022]
Abstract
The somatic gonad of the nematode Caenorhabditis elegans exhibits highly regulated contractility during ovulation, which is essential for successful reproduction. Nonstriated actin filament networks in the myoepithelial sheath at the proximal ovary provide contractile forces to push a mature oocyte for ovulation, but the mechanism of assembly and regulation of the contractile actin networks is poorly understood. Here, we show that actin-interacting protein 1 (AIP1) is essential for the assembly of the contractile actin networks in the myoepithelial sheath. AIP1 promotes disassembly of actin filaments in the presence of actin depolymerizing factor (ADF)/cofilin. C. elegans has two AIP1 genes, unc-78 and aipl-1. Mutation or RNA interference of a single AIP1 isoform causes only minor impacts on reproduction. However, simultaneous depletion of the two AIP1 isoforms causes sterility. AIP1-depleted animals show very weak contractility of the myoepithelial sheath and fail to ovulate a mature oocyte, which results in accumulation of endomitotic oocytes in the ovary. Depletion of AIP1 prevents assembly of actin networks and causes abnormal aggregation of actin as well as ADF/cofilin in the myoepithelial sheath. These results indicate that two AIP1 isoforms have redundant roles in assembly of the contractile apparatuses necessary for C. elegans reproduction.
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Affiliation(s)
- Kanako Ono
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, Georgia
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38
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Kuroyanagi H. Switch-like regulation of tissue-specific alternative pre-mRNA processing patterns revealed by customized fluorescence reporters. WORM 2013; 2:e23834. [PMID: 24778931 PMCID: PMC3875643 DOI: 10.4161/worm.23834] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 01/27/2013] [Accepted: 01/30/2013] [Indexed: 12/01/2022]
Abstract
Alternative processing of precursor mRNAs (pre-mRNAs), including alternative transcription start sites, alternative splicing and alternative polyadenylation, is the major source of protein diversity and plays crucial roles in development, differentiation and diseases in higher eukaryotes. It is estimated from microarray analyses and deep sequencing of mRNAs from synchronized worms that up to 25% of protein-coding genes in Caenorhabditis elegans undergo alternative pre-mRNA processing and that many of them are subject to developmental regulation. Recent progress in visualizing the alternative pre-mRNA processing patterns in living worms with custom-designed fluorescence reporters has enabled genetic analyses of the regulatory mechanisms for alternative processing events of interest in vivo. Expression of the tissue-specific isoforms of actin depolymerising factor (ADF)/cofilin, UNC-60A and UNC-60B, is regulated by a combination of alternative splicing and alternative polyadenylation of pre-mRNA from a single gene unc-60. We recently found that muscle-specific splicing regulators ASD-2 and SUP-12 cooperatively switch the pre-mRNA processing patterns of the unc-60 gene in body wall muscles. Here I summarize the bichromatic fluorescence reporter system utilized for visualizing the tissue-specific alternative processing patterns of the unc-60 pre-mRNA. I also discuss the model for the coordinated regulation of the UNC-60B-type pre-mRNA processing in body wall muscles by ASD-2 and SUP-12.
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Affiliation(s)
- Hidehito Kuroyanagi
- Laboratory of Gene Expression; Medical Research Institute; Tokyo Medical and Dental University; Tokyo, Japan
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Shen Q, He B, Lu N, Conradt B, Grant BD, Zhou Z. Phagocytic receptor signaling regulates clathrin and epsin-mediated cytoskeletal remodeling during apoptotic cell engulfment in C. elegans. Development 2013; 140:3230-43. [PMID: 23861060 PMCID: PMC3931732 DOI: 10.1242/dev.093732] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The engulfment and subsequent degradation of apoptotic cells by phagocytes is an evolutionarily conserved process that efficiently removes dying cells from animal bodies during development. Here, we report that clathrin heavy chain (CHC-1), a membrane coat protein well known for its role in receptor-mediated endocytosis, and its adaptor epsin (EPN-1) play crucial roles in removing apoptotic cells in Caenorhabditis elegans. Inactivating epn-1 or chc-1 disrupts engulfment by impairing actin polymerization. This defect is partially suppressed by inactivating UNC-60, a cofilin ortholog and actin server/depolymerization protein, further indicating that EPN-1 and CHC-1 regulate actin assembly during pseudopod extension. CHC-1 is enriched on extending pseudopods together with EPN-1, in an EPN-1-dependent manner. Epistasis analysis places epn-1 and chc-1 in the same cell-corpse engulfment pathway as ced-1, ced-6 and dyn-1. CED-1 signaling is necessary for the pseudopod enrichment of EPN-1 and CHC-1. CED-1, CED-6 and DYN-1, like EPN-1 and CHC-1, are essential for the assembly and stability of F-actin underneath pseudopods. We propose that in response to CED-1 signaling, CHC-1 is recruited to the phagocytic cup through EPN-1 and acts as a scaffold protein to organize actin remodeling. Our work reveals novel roles of clathrin and epsin in apoptotic-cell internalization, suggests a Hip1/R-independent mechanism linking clathrin to actin assembly, and ties the CED-1 pathway to cytoskeleton remodeling.
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Affiliation(s)
- Qian Shen
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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ATP-dependent regulation of actin monomer-filament equilibrium by cyclase-associated protein and ADF/cofilin. Biochem J 2013; 453:249-59. [PMID: 23672398 DOI: 10.1042/bj20130491] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
CAP (cyclase-associated protein) is a conserved regulator of actin filament dynamics. In the nematode Caenorhabditis elegans, CAS-1 is an isoform of CAP that is expressed in striated muscle and regulates sarcomeric actin assembly. In the present study, we report that CAS-2, a second CAP isoform in C. elegans, attenuates the actin-monomer-sequestering effect of ADF (actin depolymerizing factor)/cofilin to increase the steady-state levels of actin filaments in an ATP-dependent manner. CAS-2 binds to actin monomers without a strong preference for either ATP- or ADP-actin. CAS-2 strongly enhances the exchange of actin-bound nucleotides even in the presence of UNC-60A, a C. elegans ADF/cofilin that inhibits nucleotide exchange. UNC-60A induces the depolymerization of actin filaments and sequesters actin monomers, whereas CAS-2 reverses the monomer-sequestering effect of UNC-60A in the presence of ATP, but not in the presence of only ADP or the absence of ATP or ADP. A 1:100 molar ratio of CAS-2 to UNC-60A is sufficient to increase actin filaments. CAS-2 has two independent actin-binding sites in its N- and C-terminal halves, and the C-terminal half is necessary and sufficient for the observed activities of the full-length CAS-2. These results suggest that CAS-2 (CAP) and UNC-60A (ADF/cofilin) are important in the ATP-dependent regulation of the actin monomer-filament equilibrium.
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ADF/cofilin is not essential but is critically important for actin activities during phagocytosis in Tetrahymena thermophila. EUKARYOTIC CELL 2013; 12:1080-6. [PMID: 23729382 DOI: 10.1128/ec.00074-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
ADF/cofilin is a highly conserved actin-modulating protein. Reorganization of the actin cytoskeleton in vivo through severing and depolymerizing of F-actin by this protein is essential for various cellular events, such as endocytosis, phagocytosis, cytokinesis, and cell migration. We show that in the ciliate Tetrahymena thermophila, the ADF/cofilin homologue Adf73p associates with actin on nascent food vacuoles. Overexpression of Adf73p disrupted the proper localization of actin and inhibited the formation of food vacuoles. In vitro, recombinant Adf73p promoted the depolymerization of filaments made of T. thermophila actin (Act1p). Knockout cells lacking the ADF73 gene are viable but grow extremely slowly and have a severely decreased rate of food vacuole formation. Knockout cells have abnormal aggregates of actin in the cytoplasm. Surprisingly, unlike the case in animals and yeasts, in Tetrahymena, ADF/cofilin is not required for cytokinesis. Thus, the Tetrahymena model shows promise for future studies of the role of ADF/cofilin in vivo.
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Ohno G, Ono K, Togo M, Watanabe Y, Ono S, Hagiwara M, Kuroyanagi H. Muscle-specific splicing factors ASD-2 and SUP-12 cooperatively switch alternative pre-mRNA processing patterns of the ADF/cofilin gene in Caenorhabditis elegans. PLoS Genet 2012; 8:e1002991. [PMID: 23071450 PMCID: PMC3469465 DOI: 10.1371/journal.pgen.1002991] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 08/10/2012] [Indexed: 11/18/2022] Open
Abstract
Pre-mRNAs are often processed in complex patterns in tissue-specific manners to produce a variety of protein isoforms from single genes. However, mechanisms orchestrating the processing of the entire transcript are not well understood. Muscle-specific alternative pre-mRNA processing of the unc-60 gene in Caenorhabditis elegans, encoding two tissue-specific isoforms of ADF/cofilin with distinct biochemical properties in regulating actin organization, provides an excellent in vivo model of complex and tissue-specific pre-mRNA processing; it consists of a single first exon and two separate series of downstream exons. Here we visualize the complex muscle-specific processing pattern of the unc-60 pre-mRNA with asymmetric fluorescence reporter minigenes. By disrupting juxtaposed CUAAC repeats and UGUGUG stretch in intron 1A, we demonstrate that these elements are required for retaining intron 1A, as well as for switching the processing patterns of the entire pre-mRNA from non-muscle-type to muscle-type. Mutations in genes encoding muscle-specific RNA-binding proteins ASD-2 and SUP-12 turned the colour of the unc-60 reporter worms. ASD-2 and SUP-12 proteins specifically and cooperatively bind to CUAAC repeats and UGUGUG stretch in intron 1A, respectively, to form a ternary complex in vitro. Immunohistochemical staining and RT-PCR analyses demonstrate that ASD-2 and SUP-12 are also required for switching the processing patterns of the endogenous unc-60 pre-mRNA from UNC-60A to UNC-60B in muscles. Furthermore, systematic analyses of partially spliced RNAs reveal the actual orders of intron removal for distinct mRNA isoforms. Taken together, our results demonstrate that muscle-specific splicing factors ASD-2 and SUP-12 cooperatively promote muscle-specific processing of the unc-60 gene, and provide insight into the mechanisms of complex pre-mRNA processing; combinatorial regulation of a single splice site by two tissue-specific splicing regulators determines the binary fate of the entire transcript.
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Affiliation(s)
- Genta Ohno
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Research Fellowship for Young Scientists, Japan Society for the Promotion of Science (JSPS), Tokyo, Japan
| | - Kanako Ono
- Department of Pathology, Emory University, Atlanta, Georgia, United States of America
| | - Marina Togo
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yohei Watanabe
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, Georgia, United States of America
| | - Masatoshi Hagiwara
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Hidehito Kuroyanagi
- Laboratory of Gene Expression, Graduate School of Biomedical Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Functional Genomics, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama, Japan
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Melo JA, Ruvkun G. Inactivation of conserved C. elegans genes engages pathogen- and xenobiotic-associated defenses. Cell 2012; 149:452-66. [PMID: 22500807 DOI: 10.1016/j.cell.2012.02.050] [Citation(s) in RCA: 281] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 01/02/2012] [Accepted: 02/23/2012] [Indexed: 12/18/2022]
Abstract
The nematode C. elegans is attracted to nutritious bacteria and is repelled by pathogens and toxins. Here we show that RNAi and toxin-mediated disruption of core cellular activities, including translation, respiration, and protein turnover, stimulate behavioral avoidance of normally attractive bacteria. RNAi of these and other essential processes induces expression of detoxification and innate immune effectors, even in the absence of toxins or pathogens. Disruption of core processes in non-neuronal tissues was sufficient to stimulate aversion behavior, revealing a neuroendocrine axis of control that additionally required serotonergic and Jnk kinase signaling pathways. We propose that surveillance pathways overseeing core cellular activities allow animals to detect invading pathogens that deploy toxins and virulence factors to undermine vital host functions. Variation in cellular surveillance and endocrine pathways controlling behavior, detoxification, and immunity selected by past toxin or microbial interactions could underlie aberrant responses to foods, medicines, and microbes.
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Affiliation(s)
- Justine A Melo
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
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Caenorhabditis elegans screen reveals role of PAR-5 in RAB-11-recycling endosome positioning and apicobasal cell polarity. Nat Cell Biol 2012; 14:666-76. [PMID: 22634595 DOI: 10.1038/ncb2508] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 04/19/2012] [Indexed: 02/08/2023]
Abstract
Apically enriched Rab11-positive recycling endosomes (Rab11-REs) are important for establishing and maintaining epithelial polarity. Yet, little is known about the molecules controlling trafficking of Rab11-REs in an epithelium in vivo. Here, we report a genome-wide, image-based RNA interference screen for regulators of Rab11-RE positioning and transport of an apical membrane protein (PEPT-1) in C. elegans intestine. Among the 356 screen hits was the 14-3-3 and partitioning defective protein PAR-5, which we found to be specifically required for Rab11-RE positioning and apicobasal polarity maintenance. Depletion of PAR-5 induced abnormal clustering of Rab11-REs to ectopic sites at the basolateral cortex containing F-actin and other apical domain components. This phenotype required key regulators of F-actin dynamics and polarity, such as Rho GTPases (RHO-1 and the Rac1 orthologue CED-10) and apical PAR proteins. Our data suggest that PAR-5 acts as a regulatory hub for a polarity-maintaining network required for apicobasal asymmetry of F-actin and proper Rab11-RE positioning.
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Nomura K, Ono K, Ono S. CAS-1, a C. elegans cyclase-associated protein, is required for sarcomeric actin assembly in striated muscle. J Cell Sci 2012; 125:4077-89. [PMID: 22623720 DOI: 10.1242/jcs.104950] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Assembly of contractile apparatuses in striated muscle requires precisely regulated reorganization of the actin cytoskeletal proteins into sarcomeric organization. Regulation of actin filament dynamics is one of the essential processes of myofibril assembly, but the mechanism of actin regulation in striated muscle is not clearly understood. Actin depolymerizing factor (ADF)/cofilin is a key enhancer of actin filament dynamics in striated muscle in both vertebrates and nematodes. Here, we report that CAS-1, a cyclase-associated protein in Caenorhabditis elegans, promotes ADF/cofilin-dependent actin filament turnover in vitro and is required for sarcomeric actin organization in striated muscle. CAS-1 is predominantly expressed in striated muscle from embryos to adults. In vitro, CAS-1 binds to actin monomers and enhances exchange of actin-bound ATP/ADP even in the presence of UNC-60B, a muscle-specific ADF/cofilin that inhibits the nucleotide exchange. As a result, CAS-1 and UNC-60B cooperatively enhance actin filament turnover. The two proteins also cooperate to shorten actin filaments. A cas-1 mutation is homozygous lethal with defects in sarcomeric actin organization. cas-1-mutant embryos and worms have aggregates of actin in muscle cells, and UNC-60B is mislocalized to the aggregates. These results provide genetic and biochemical evidence that cyclase-associated protein is a critical regulator of sarcomeric actin organization in striated muscle.
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Affiliation(s)
- Kazumi Nomura
- Department of Pathology and Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
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Agrawal PB, Joshi M, Savic T, Chen Z, Beggs AH. Normal myofibrillar development followed by progressive sarcomeric disruption with actin accumulations in a mouse Cfl2 knockout demonstrates requirement of cofilin-2 for muscle maintenance. Hum Mol Genet 2012; 21:2341-56. [PMID: 22343409 DOI: 10.1093/hmg/dds053] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Cofilin-2, a small actin-binding protein and member of the AC protein family that includes cofilin-1 and destrin, is predominantly expressed at sarcomeres in skeletal and cardiac muscles. The role of cofilin-2 in muscle development and function is unclear. In humans, recessive cofilin-2 mutations have been associated with nemaline myopathy with minicores. To investigate the functional role of cofilin-2 in vivo, we generated constitutive and muscle-specific cofilin-2-deficient mice using a cre-loxP strategy. Cofilin-2-deficient mice were similar to their wild-type (WT) littermates at birth, but died by day 8. They were significantly smaller, severely weak and had very little milk in their stomachs. The sarcomeric structure was intact at birth, but by Day 7, skeletal muscles showed severe sarcomeric disruptions starting at the Z-line, along with filamentous actin accumulations consistent with a lack of actin depolymerization activity. Cofilin-2-deficient muscles contained elevated numbers of slow fibers and exhibited upregulation of slow fiber-specific genes. Increased amounts of other sarcomeric proteins including α-actinin-2, α-sarcomeric actin and tropomyosin were also present. While destrin was not expressed in either WT or cofilin-2-deficient muscles, cofilin-1 was similarly expressed in developing myofibers of both genotypes. There was no evidence for compensatory changes in expression of either family member in cofilin-2-deficient tissues. The onset of pathology and weakness in cofilin-2-deficient muscles correlated with normal developmental loss of cofilin-1 expression within myofibers, suggesting that cofilin-1 serves as an early developmental sarcomeric isoform. Overall, cofilin-2, although not critical for muscle development, is essential for muscle maintenance.
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Affiliation(s)
- Pankaj B Agrawal
- Genomics Program and Division of Genetics, The Manton Center for Orphan Disease Research, Boston, MA 02115, USA.
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Chen Q, Pollard TD. Actin filament severing by cofilin is more important for assembly than constriction of the cytokinetic contractile ring. ACTA ACUST UNITED AC 2011; 195:485-98. [PMID: 22024167 PMCID: PMC3206353 DOI: 10.1083/jcb.201103067] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
When fission yeast express mutant cofilin that is inefficient at actin filament severing, cytokinetic contractile ring formation is severely impaired, but ring contraction proceeds efficiently. We created two new mutants of fission yeast cofilin to investigate why cytokinesis in many organisms depends on this small actin-binding protein. These mutant cofilins bound actin monomers normally, but bound and severed ADP-actin filaments much slower than wild-type cofilin. Cells depending on mutant cofilins condensed nodes, precursors of the contractile ring, into clumps rather than rings. Starting from clumped nodes, mutant cells slowly assembled rings from diverse intermediate structures including spiral strands containing actin filaments and other contractile ring proteins. This process in mutant cells depended on α-actinin. These slowly assembled contractile rings constricted at a normal rate but with more variability, indicating ring constriction is not very sensitive to defects in severing by cofilin. Computer simulations of the search-capture-pull and release model of contractile ring formation predicted that nodes clump when the release step is slow, so cofilin severing of actin filament connections between nodes likely contributes to the release step.
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Affiliation(s)
- Qian Chen
- Department of Molecular Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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Biochemical and cell biological analysis of actin in the nematode Caenorhabditis elegans. Methods 2011; 56:11-7. [PMID: 21945576 DOI: 10.1016/j.ymeth.2011.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 09/06/2011] [Accepted: 09/10/2011] [Indexed: 11/21/2022] Open
Abstract
The nematode Caenorhabditis elegans has long been a useful model organism for muscle research. Its body wall muscle is obliquely striated muscle and exhibits structural similarities with vertebrate striated muscle. Actin is the core component of the muscle thin filaments, which are highly ordered in sarcomeric structures in striated muscle. Genetic studies have identified genes that regulate proper organization and function of actin filaments in C. elegans muscle, and sequence of the worm genome has revealed a number of conserved candidate genes that may regulate actin. To precisely understand the functions of actin-binding proteins, such genetic and genomic studies need to be complemented by biochemical characterization of these actin-binding proteins in vitro. This article describes methods for purification and biochemical characterization of actin from C. elegans. Although rabbit muscle actin is commonly used to characterize actin-binding proteins from many eukaryotic organisms, we detect several quantitative differences between C. elegans actin and rabbit muscle actin, highlighting that use of actin from an appropriate source is important in some cases. Additionally, we describe probes for cell biological analysis of actin in C. elegans.
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Poukkula M, Kremneva E, Serlachius M, Lappalainen P. Actin-depolymerizing factor homology domain: a conserved fold performing diverse roles in cytoskeletal dynamics. Cytoskeleton (Hoboken) 2011; 68:471-90. [PMID: 21850706 DOI: 10.1002/cm.20530] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/29/2011] [Accepted: 08/05/2011] [Indexed: 11/09/2022]
Abstract
Actin filaments form contractile and protrusive structures that play central roles in many processes such as cell migration, morphogenesis, endocytosis, and cytokinesis. During these processes, the dynamics of the actin filaments are precisely regulated by a large array of actin-binding proteins. The actin-depolymerizing factor homology (ADF-H) domain is a structurally conserved protein motif, which promotes cytoskeletal dynamics by interacting with monomeric and/or filamentous actin, and with the Arp2/3 complex. Despite their structural homology, the five classes of ADF-H domain proteins display distinct biochemical activities and cellular roles, only parts of which are currently understood. ADF/cofilin promotes disassembly of aged actin filaments, whereas twinfilin inhibits actin filament assembly via sequestering actin monomers and interacting with filament barbed ends. GMF does not interact with actin, but instead binds Arp2/3 complex and promotes dissociation of Arp2/3-mediated filament branches. Abp1 and drebrin are multidomain proteins that interact with actin filaments and regulate the activities of other proteins during various actin-dependent processes. The exact function of coactosin is currently incompletely understood. In this review article, we discuss the biochemical functions, cellular roles, and regulation of the five groups of ADF-H domain proteins.
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Affiliation(s)
- Minna Poukkula
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Finland
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Ono S, Nomura K, Hitosugi S, Tu DK, Lee JA, Baillie DL, Ono K. The two actin-interacting protein 1 genes have overlapping and essential function for embryonic development in Caenorhabditis elegans. Mol Biol Cell 2011; 22:2258-69. [PMID: 21551072 PMCID: PMC3128528 DOI: 10.1091/mbc.e10-12-0934] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Disassembly of actin filaments by actin-depolymerizing factor (ADF)/cofilin and actin-interacting protein 1 (AIP1) is a conserved mechanism to promote reorganization of the actin cytoskeleton. We previously reported that unc-78, an AIP1 gene in the nematode Caenorhabditis elegans, is required for organized assembly of sarcomeric actin filaments in the body wall muscle. unc-78 functions in larval and adult muscle, and an unc-78-null mutant is homozygous viable and shows only weak phenotypes in embryos. Here we report that a second AIP1 gene, aipl-1 (AIP1-like gene-1), has overlapping function with unc-78, and that depletion of the two AIP1 isoforms causes embryonic lethality. A single aipl-1-null mutation did not cause a detectable phenotype. However, depletion of both unc-78 and aipl-1 arrested development at late embryonic stages due to severe disorganization of sarcomeric actin filaments in body wall muscle. In vitro, both AIPL-1 and UNC-78 preferentially cooperated with UNC-60B, a muscle-specific ADF/cofilin isoform, in actin filament disassembly but not with UNC-60A, a nonmuscle ADF/cofilin. AIPL-1 is expressed in embryonic muscle, and forced expression of AIPL-1 in adult muscle compensated for the function of UNC-78. Thus our results suggest that enhancement of actin filament disassembly by ADF/cofilin and AIP1 proteins is critical for embryogenesis.
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Affiliation(s)
- Shoichiro Ono
- Department of Pathology, Emory University, Atlanta, GA 30322, USA.
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