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Donkervoort S, Chan SHS, Hayes LH, Bradley N, Nguyen D, Leach ME, Mohassel P, Hu Y, Thangarajh M, Bharucha-Goebel D, Kan A, Ho RSL, Reyes CA, Nance J, Moore SA, Foley AR, Bönnemann CG. Cytoplasmic body pathology in severe ACTA1-related myopathy in the absence of typical nemaline rods. Neuromuscul Disord 2017; 27:531-536. [PMID: 28416349 PMCID: PMC5918412 DOI: 10.1016/j.nmd.2017.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 01/24/2017] [Accepted: 02/24/2017] [Indexed: 02/07/2023]
Abstract
Mutations in ACTA1 cause a group of myopathies with expanding clinical and histopathological heterogeneity. We describe three patients with severe ACTA1-related myopathy who have muscle fiber cytoplasmic bodies but no classic nemaline rods. Patient 1 is a five-year-old boy who presented at birth with severe weakness and respiratory failure, requiring mechanical ventilation. Whole exome sequencing identified a heterozygous c.282C>A (p.Asn94Lys) ACTA1 mutation. Patients 2 and 3 were twin boys with hypotonia, severe weakness, and respiratory insufficiency at birth requiring mechanical ventilation. Both died at 6 months of age. The same heterozygous c.282C>A (p.Asn94Lys) ACTA1 mutation was identified by whole exome sequencing. We conclude that clinically severe ACTA1-related myopathy can present with muscle morphological findings suggestive of cytoplasmic body myopathy in the absence of definite nemaline rods. The Asn94Lys mutation in skeletal muscle sarcomeric α-actin may be linked to this histological appearance. These novel ACTA1 cases also illustrate the successful application of whole exome sequencing in directly arriving at a candidate genetic diagnosis in patients with unexpected phenotypic and histologic features for a known neuromuscular gene.
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Affiliation(s)
- Sandra Donkervoort
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - Sophelia H S Chan
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong SAR
| | - Leslie H Hayes
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA; Boston Children's Hospital, Boston, MA, USA
| | - Nathaniel Bradley
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - David Nguyen
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - Meganne E Leach
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA; Children's National Health System, Washington, DC, USA
| | - Payam Mohassel
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - Ying Hu
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | | | - Diana Bharucha-Goebel
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA; Children's National Health System, Washington, DC, USA
| | - Amanda Kan
- Department of Pathology and Clinical Biochemistry, The Queen Mary Hospital, Hong Kong SAR
| | - Ronnie S L Ho
- Department of Pathology and Clinical Biochemistry, The Queen Mary Hospital, Hong Kong SAR
| | | | - Jessica Nance
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Steven A Moore
- Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - A Reghan Foley
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA
| | - Carsten G Bönnemann
- National Institutes of Health, Neuromuscular and Neurogenetic Disorders of Childhood Section, Bethesda, MD, USA.
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202
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Michaels TCT, Liu LX, Meisl G, Knowles TPJ. Physical principles of filamentous protein self-assembly kinetics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:153002. [PMID: 28170349 DOI: 10.1088/1361-648x/aa5f10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The polymerization of proteins and peptides into filamentous supramolecular structures is an elementary form of self-organization of key importance to the functioning biological systems, as in the case of actin biofilaments that compose the cellular cytoskeleton. Aberrant filamentous protein self-assembly, however, is associated with undesired effects and severe clinical disorders, such as Alzheimer's and Parkinson's diseases, which, at the molecular level, are associated with the formation of certain forms of filamentous protein aggregates known as amyloids. Moreover, due to their unique physicochemical properties, protein filaments are finding extensive applications as biomaterials for nanotechnology. With all these different factors at play, the field of filamentous protein self-assembly has experienced tremendous activity in recent years. A key question in this area has been to elucidate the microscopic mechanisms through which filamentous aggregates emerge from dispersed proteins with the goal of uncovering the underlying physical principles. With the latest developments in the mathematical modeling of protein aggregation kinetics as well as the improvement of the available experimental techniques it is now possible to tackle many of these complex systems and carry out detailed analyses of the underlying microscopic steps involved in protein filament formation. In this paper, we review some classical and modern kinetic theories of protein filament formation, highlighting their use as a general strategy for quantifying the molecular-level mechanisms and transition states involved in these processes.
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Affiliation(s)
- Thomas C T Michaels
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States of America
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203
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Gray KT, Kostyukova AS, Fath T. Actin regulation by tropomodulin and tropomyosin in neuronal morphogenesis and function. Mol Cell Neurosci 2017; 84:48-57. [PMID: 28433463 DOI: 10.1016/j.mcn.2017.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 04/06/2017] [Accepted: 04/11/2017] [Indexed: 12/26/2022] Open
Abstract
Actin is a profoundly influential protein; it impacts, among other processes, membrane morphology, cellular motility, and vesicle transport. Actin can polymerize into long filaments that push on membranes and provide support for intracellular transport. Actin filaments have polar ends: the fast-growing (barbed) end and the slow-growing (pointed) end. Depolymerization from the pointed end supplies monomers for further polymerization at the barbed end. Tropomodulins (Tmods) cap pointed ends by binding onto actin and tropomyosins (Tpms). Tmods and Tpms have been shown to regulate many cellular processes; however, very few studies have investigated their joint role in the nervous system. Recent data directly indicate that they can modulate neuronal morphology. Additional studies suggest that Tmod and Tpm impact molecular processes influential in synaptic signaling. To facilitate future research regarding their joint role in actin regulation in the nervous system, we will comprehensively discuss Tpm and Tmod and their known functions within molecular systems that influence neuronal development.
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Affiliation(s)
- Kevin T Gray
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States; School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Alla S Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington, United States.
| | - Thomas Fath
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
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204
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Mamon LA, Ginanova VR, Kliver SF, Yakimova AO, Atsapkina AA, Golubkova EV. RNA-binding proteins of the NXF (nuclear export factor) family and their connection with the cytoskeleton. Cytoskeleton (Hoboken) 2017; 74:161-169. [PMID: 28296067 DOI: 10.1002/cm.21362] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/04/2017] [Accepted: 03/08/2017] [Indexed: 02/05/2023]
Abstract
The mutual relationship between mRNA and the cytoskeleton can be seen from two points of view. On the one hand, the cytoskeleton is necessary for mRNA trafficking and anchoring to subcellular domains. On the other hand, cytoskeletal growth and rearrangement require the translation of mRNAs that are connected to the cytoskeleton. β-actin mRNA localization may influence dynamic changes in the actin cytoskeleton. In the cytoplasm, long-lived mRNAs exist in the form of RNP (ribonucleoprotein) complexes, where they interact with RNA-binding proteins, including NXF (Nuclear eXport Factor). Dm NXF1 is an evolutionarily conserved protein in Drosophila melanogaster that has orthologs in different animals. The universal function of nxf1 genes is the nuclear export of different mRNAs in various organisms. In this mini-review, we briefly discuss the evidence demonstrating that Dm NXF1 fulfils not only universal but also specialized cytoplasmic functions. This protein is detected not only in the nucleus but also in the cytoplasm. It is a component of neuronal granules. Dm NXF1 marks nuclear division spindles during early embryogenesis and the dense body on one side of the elongated spermatid nuclei. The characteristic features of sbr mutants (sbr10 and sbr5 ) are impairment of chromosome segregation and spindle formation anomalies during female meiosis. sbr12 mutant sterile males with immobile spermatozoa exhibit disturbances in the axoneme, mitochondrial derivatives and cytokinesis. These data allow us to propose that the Dm NXF1 proteins transport certain mRNAs in neurites and interact with localized mRNAs that are necessary for dynamic changes of the cytoskeleton.
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Affiliation(s)
- L A Mamon
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
| | - V R Ginanova
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
| | - S F Kliver
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
| | - A O Yakimova
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
| | - A A Atsapkina
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
| | - E V Golubkova
- Department of Genetics and Biotechnology, Faculty of Biology, St Petersburg State University Universitetskaya nab. 7-9, Saint-Petersburg, 199034, Russia
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205
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Wirshing ACE, Cram EJ. Myosin activity drives actomyosin bundle formation and organization in contractile cells of the Caenorhabditis elegans spermatheca. Mol Biol Cell 2017; 28:1937-1949. [PMID: 28331075 PMCID: PMC5541844 DOI: 10.1091/mbc.e17-01-0029] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 12/04/2022] Open
Abstract
The contractile myoepithelial cells of the Caenorhabditis elegans somatic gonad are stretched by oocyte entry and subsequently contract to expel the fertilized embryo into the uterus. Formation of aligned, parallel actomyosin bundles during the first ovulation is triggered by oocyte entry and regulated by myosin contractility. Stress fibers—contractile actomyosin bundles—are important for cellular force production and adaptation to physical stress and have been well studied within the context of cell migration. However, less is known about actomyosin bundle formation and organization in vivo and in specialized contractile cells, such as smooth muscle and myoepithelial cells. The Caenorhabditis elegans spermatheca is a bag-like organ of 24 myoepithelial cells that houses the sperm and is the site of fertilization. During ovulation, spermathecal cells are stretched by oocyte entry and then coordinately contract to expel the fertilized embryo into the uterus. Here we use four-dimensional confocal microscopy of live animals to observe changes to spermathecal actomyosin network organization during cell stretch and contraction. Oocyte entry is required to trigger cell contraction and concomitant production of parallel actomyosin bundles. Actomyosin bundle size, connectivity, spacing, and orientation are regulated by myosin activity. We conclude that myosin drives actomyosin bundle production and that myosin activity is tightly regulated during ovulation to produce an optimally organized actomyosin network in C. elegans spermathecae.
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Affiliation(s)
| | - Erin J Cram
- Department of Biology, Northeastern University, Boston, MA 02115
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206
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Li N, Wong CK, Cheng CY. Plastins regulate ectoplasmic specialization via its actin bundling activity on microfilaments in the rat testis. Asian J Androl 2017; 18:716-22. [PMID: 26608945 PMCID: PMC5000794 DOI: 10.4103/1008-682x.166583] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Plastins are a family of actin binding proteins (ABPs) known to cross-link actin microfilaments in mammalian cells, creating actin microfilament bundles necessary to confer cell polarity and cell shape. Plastins also support cell movement in response to changes in environment, involved in cell/tissue growth and development. They also confer plasticity to cells and tissues in response to infection or other pathological conditions (e.g., inflammation). In the testis, the cell-cell anchoring junction unique to the testis that is found at the Sertoli cell-cell interface at the blood-testis barrier (BTB) and at the Sertoli-spermatid (e.g., 8–19 spermatids in the rat testis) is the basal and the apical ectoplasmic specialization (ES), respectively. The ES is an F-actin-rich anchoring junction constituted most notably by actin microfilament bundles. A recent report using RNAi that specifically knocks down plastin 3 has yielded some insightful information regarding the mechanism by which plastin 3 regulates the status of actin microfilament bundles at the ES via its intrinsic actin filament bundling activity. Herein, we provide a brief review on the role of plastins in the testis in light of this report, which together with recent findings in the field, we propose a likely model by which plastins regulate ES function during the epithelial cycle of spermatogenesis via their intrinsic activity on actin microfilament organization in the rat testis.
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Affiliation(s)
- Nan Li
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York 10065, USA
| | - Chris Kc Wong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research, Population Council, 1230 York Avenue, New York 10065, USA
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207
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Di Blasio L, Gagliardi PA, Puliafito A, Primo L. Serine/Threonine Kinase 3-Phosphoinositide-Dependent Protein Kinase-1 (PDK1) as a Key Regulator of Cell Migration and Cancer Dissemination. Cancers (Basel) 2017; 9:cancers9030025. [PMID: 28287465 PMCID: PMC5366820 DOI: 10.3390/cancers9030025] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/07/2017] [Accepted: 03/08/2017] [Indexed: 02/03/2023] Open
Abstract
Dissecting the cellular signaling that governs the motility of eukaryotic cells is one of the fundamental tasks of modern cell biology, not only because of the large number of physiological processes in which cell migration is crucial, but even more so because of the pathological ones, in particular tumor invasion and metastasis. Cell migration requires the coordination of at least four major processes: polarization of intracellular signaling, regulation of the actin cytoskeleton and membrane extension, focal adhesion and integrin signaling and contractile forces generation and rear retraction. Among the molecular components involved in the regulation of locomotion, the phosphatidylinositol-3-kinase (PI3K) pathway has been shown to exert fundamental role. A pivotal node of such pathway is represented by the serine/threonine kinase 3-phosphoinositide-dependent protein kinase-1 (PDPK1 or PDK1). PDK1, and the majority of its substrates, belong to the AGC family of kinases (related to cAMP-dependent protein kinase 1, cyclic Guanosine monophosphate-dependent protein kinase and protein kinase C), and control a plethora of cellular processes, downstream either to PI3K or to other pathways, such as RAS GTPase-MAPK (mitogen-activated protein kinase). Interestingly, PDK1 has been demonstrated to be crucial for the regulation of each step of cell migration, by activating several proteins such as protein kinase B/Akt (PKB/Akt), myotonic dystrophy-related CDC42-binding kinases alpha (MRCKα), Rho associated coiled-coil containing protein kinase 1 (ROCK1), phospholipase C gamma 1 (PLCγ1) and β3 integrin. Moreover, PDK1 regulates cancer cell invasion as well, thus representing a possible target to prevent cancer metastasis in human patients. The aim of this review is to summarize the various mechanisms by which PDK1 controls the cell migration process, from cell polarization to actin cytoskeleton and focal adhesion regulation, and finally, to discuss the evidence supporting a role for PDK1 in cancer cell invasion and dissemination.
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Affiliation(s)
- Laura Di Blasio
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
| | | | | | - Luca Primo
- Candiolo Cancer Institute FPO-IRCCS, 10060 Candiolo, Torino, Italy.
- Department of Oncology, University of Torino, 10043 Orbassano, Torino, Italy.
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208
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Proteomic analysis of chondromodulin-I-induced differentiation of mesenchymal stem cells into chondrocytes. J Proteomics 2017; 159:1-18. [PMID: 28263889 DOI: 10.1016/j.jprot.2017.02.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/13/2017] [Accepted: 02/26/2017] [Indexed: 12/16/2022]
Abstract
To identify novel proteins that might help clarify the molecular mechanisms underlying chondromodulin-I (ChM-I) induction of mesenchymal stem cells (MSCs) differentiate into chondrocytes. MSCs are triggered to differentiate into chondrocytes, which are recognized as important factors in cartilage tissue engineering. ChM-I is a glycoprotein that stimulates the growth of chondrocytes and inhibits angiogenesis in vitro. In this study, the proteomic approach was used to evaluate protein changes between undifferentiated MSCs and ChM-I-transfected MSCs. The expression of the protein spots was analyzed using two-dimensional gel electrophoresis. Then, 14 protein spots were identified between MSCs and ChM-I-transfected MSCs. 309 proteins were identified using mass spectrometry (MS). The differentially regulated proteins were categorized and annotated using Protein Analysis Through Evolutionary Relationships (PANTHER) analysis with the aid of the Database for Annotation, Visualization and Integrated Discovery (DAVID) tool. These proteins are included in a variety of metabolic pathways and signal transduction pathways, such as focal adhesion, glycolysis, actin cytoskeleton regulation, and ribosome. These results demonstrate novel information about the molecular mechanism by which ChM-I induce MSCs to differentiate into chondrocytes. These results also provide a solid foundation for the development of tissue-engineered cartilage.
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209
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LINGO-1 Regulates Oligodendrocyte Differentiation through the Cytoplasmic Gelsolin Signaling Pathway. J Neurosci 2017; 37:3127-3137. [PMID: 28193690 DOI: 10.1523/jneurosci.3722-16.2017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/19/2017] [Accepted: 02/06/2017] [Indexed: 01/07/2023] Open
Abstract
Differentiation and maturation of oligodendrocyte progenitor cells (OPCs) involve the assembly and disassembly of actin microfilaments. However, how actin dynamics are regulated during this process remains poorly understood. Leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of OPC differentiation. We discovered that anti-LINGO-1 antibody-promoted OPC differentiation was accompanied by upregulation of cytoplasmic gelsolin (cGSN), an abundant actin-severing protein involved in the depolymerization of actin filaments. Treating rat OPCs with cGSN siRNA reduced OPC differentiation, whereas overexpression of cGSN promoted OPC differentiation in vitro and remyelination in vivo Furthermore, coexpression of cGSN and LINGO-1 blocked the inhibitory effect of LINGO-1. Our study demonstrates that cGSN works downstream of LINGO-1 signaling pathway, which enhances actin dynamics and is essential for OPC morphogenesis and differentiation. This finding may lead to novel therapeutic approaches for the treatment of demyelinating diseases such as multiple sclerosis (MS).SIGNIFICANCE STATEMENT Myelin loss and subsequent axon degeneration contributes to a variety of neurological diseases, such as multiple sclerosis (MS). Understanding the regulation of myelination by oligodendrocytes is therefore critical for developing therapies for the treatment of MS. We previously demonstrated that leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of oligodendrocyte differentiation and that anti-LINGO-1 promotes remyelination in preclinical animal models for MS and in a phase II acute optic neuritis clinical trial (RENEW). The mechanism by which LINGO-1 regulates oligodendrocyte differentiation is unknown. Here, we demonstrate that LINGO-1 regulates oligodendrocyte differentiation and maturation through the cytoplasmic gelsolin signaling pathway, providing new drug targets for the treatment of demyelination diseases.
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210
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Huo Y, Xie X, Jiang B. Identification of functional pathways associated with the conditional ablation of serum response factor in Dstncorn1 mice. Mol Med Rep 2017; 15:139-145. [PMID: 27922676 PMCID: PMC5355747 DOI: 10.3892/mmr.2016.5984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 07/25/2016] [Indexed: 11/06/2022] Open
Abstract
The aim of the present study was to investigate the signaling pathways associated with functional alterations in corneal tissues following the conditional ablation of serum response factor (Srf) in Dstncorn1 mice. The gene expression profiling array GSE49688, which includes 3 samples each from the wild-type (WT), Dstncorn1 mutant (corn1) and corn1 mice following the conditional ablation of Srf from the corneal epithelium [namely rescued (res)] mouse groups, was downloaded from the Gene Expression Omnibus database. The limma package was used to identify differentially expressed genes (DEGs) among the three mouse groups. DEGs were subsequently analyzed by dynamic comparison, hierarchical clustering and pathway enrichment analysis. Pathway alteration scores were also calculated in order to study the dynamic metergasis of each identified pathway. A total of 788 DEGs were identified between the corn1 and res groups, 1,365 DEGs were identified between the corn1 and WT groups, and 852 DEGs were identified between the res and WT groups. Among these DEGs, 228 genes were differentially expressed across all three groups, and were mainly enriched in signaling pathways involved in the regulation of the actin cytoskeleton, including the cofilin 1 (CFL1), the mitogen-activated protein kinase (MAPK) signaling pathway and focal adhesion. The dilated cardiomyopathy signaling pathway displayed the highest alteration score, and was enriched with integrin and integrin β-6 (ITGB6). In conclusion, the actin cytoskeleton regulatory pathway, MAPK and dilated cardiomyopathy signaling pathways, as well as CFL1 and ITGB6 genes, may be regulated by Srf to serve important roles in the progression of corneal disease.
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211
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Abstract
In this review we discuss the history and the current state of ideas related to the mechanism of size regulation of the thick (myosin) and thin (actin) filaments in vertebrate striated muscles. Various hypotheses have been considered during of more than half century of research, recently mostly involving titin and nebulin acting as templates or 'molecular rulers', terminating exact assembly. These two giant, single-polypeptide, filamentous proteins are bound in situ along the thick and thin filaments, respectively, with an almost perfect match in the respective lengths and structural periodicities. However, evidence still questions the possibility that the proteins function as templates, or scaffolds, on which the thin and thick filaments could be assembled. In addition, the progress in muscle research during the last decades highlighted a number of other factors that could potentially be involved in the mechanism of length regulation: molecular chaperones that may guide folding and assembly of actin and myosin; capping proteins that can influence the rates of assembly-disassembly of the myofilaments; Ca2+ transients that can activate or deactivate protein interactions, etc. The entire mechanism of sarcomere assembly appears complex and highly dynamic. This mechanism is also capable of producing filaments of about the correct size without titin and nebulin. What then is the role of these proteins? Evidence points to titin and nebulin stabilizing structures of the respective filaments. This stabilizing effect, based on linear proteins of a fixed size, implies that titin and nebulin are indeed molecular rulers of the filaments. Although the proteins may not function as templates in the assembly of the filaments, they measure and stabilize exactly the same size of the functionally important for the muscles segments in each of the respective filaments.
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212
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Grintsevich EE. Remodeling of Actin Filaments by Drebrin A and Its Implications. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1006:61-82. [DOI: 10.1007/978-4-431-56550-5_5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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213
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Cofilin-1 and Other ADF/Cofilin Superfamily Members in Human Malignant Cells. Int J Mol Sci 2016; 18:ijms18010010. [PMID: 28025492 PMCID: PMC5297645 DOI: 10.3390/ijms18010010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/18/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
Identification of actin-depolymerizing factor homology (ADF-H) domains in the structures of several related proteins led first to the formation of the ADF/cofilin family, which then expanded to the ADF/cofilin superfamily. This superfamily includes the well-studied cofilin-1 (Cfl-1) and about a dozen different human proteins that interact directly or indirectly with the actin cytoskeleton, provide its remodeling, and alter cell motility. According to some data, Cfl-1 is contained in various human malignant cells (HMCs) and is involved in the formation of malignant properties, including invasiveness, metastatic potential, and resistance to chemotherapeutic drugs. The presence of other ADF/cofilin superfamily proteins in HMCs and their involvement in the regulation of cell motility were discovered with the use of various OMICS technologies. In our review, we discuss the results of the study of Cfl-1 and other ADF/cofilin superfamily proteins, which may be of interest for solving different problems of molecular oncology, as well as for the prospects of further investigations of these proteins in HMCs.
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214
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Dasgupta A, Sawant MA, Kavishwar G, Lavhale M, Sitasawad S. AECHL-1 targets breast cancer progression via inhibition of metastasis, prevention of EMT and suppression of Cancer Stem Cell characteristics. Sci Rep 2016; 6:38045. [PMID: 27974826 PMCID: PMC5156909 DOI: 10.1038/srep38045] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 11/02/2016] [Indexed: 12/30/2022] Open
Abstract
Triple negative breast cancer (TNBC) features among the most aggressive manifestations of cancer due to its enhanced metastatic potential and immunity to therapeutics which target hormone receptors. Under such scenarios, anti-cancer compounds with an ability to influence multiple targets, or an entire process, will have an advantage over specific signal transduction inhibitors. To counter the metastatic threat it is essential to target cellular components central to the processes of cancer cell migration and adaptation. Our previous work on a novel triterpenoid, AECHL-1, explored its anti-cancer potential, and linked it to elevated ER stress in cancer cells, while its anti-angiogenic potential was credited for its ability to manipulate the cytoskeleton. Here, we broaden its range of action by showing that it curbs the metastatic ability of TNBC cells, both in vitro in MDA-MB-231 cell line and in vivo, in mouse models of metastasis. AECHL-1 does so by disrupting the cytoskeletal network, and also suppressing NF-κB and β-Catenin mediated key molecular pathways. These activities also contributed to AECHL-1 mediated suppression of TGF-β/TNF-α induced Epithelial to Mesenchymal Transition (EMT) and cancer stem cell characteristic. Thus, we present AECHL-1 as a promising therapeutic inhibitor of metastatic disease.
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Affiliation(s)
- Aparajita Dasgupta
- National Centre for Cell Science, NCCS Complex, S.P. Pune University, Ganeshkhind, Pune 411007, Maharashtra, India
| | - Mithila A. Sawant
- National Centre for Cell Science, NCCS Complex, S.P. Pune University, Ganeshkhind, Pune 411007, Maharashtra, India
| | - Gayatri Kavishwar
- National Centre for Cell Science, NCCS Complex, S.P. Pune University, Ganeshkhind, Pune 411007, Maharashtra, India
| | - Manish Lavhale
- Pharmazz India Private Limited, H-6, Site-C, Surajpur Industrial area, Greater Noida, UP- 201307, India
| | - Sandhya Sitasawad
- National Centre for Cell Science, NCCS Complex, S.P. Pune University, Ganeshkhind, Pune 411007, Maharashtra, India
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215
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Skugor S, Jodaa Holm H, Bjelland AK, Pino J, Evensen Ø, Krasnov A, Wadsworth S. Nutrigenomic effects of glucosinolates on liver, muscle and distal kidney in parasite-free and salmon louse infected Atlantic salmon. Parasit Vectors 2016; 9:639. [PMID: 27955686 PMCID: PMC5153675 DOI: 10.1186/s13071-016-1921-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/28/2016] [Indexed: 12/22/2022] Open
Abstract
Background Reduction of Lepeophtheirus salmonis infection in Atlantic salmon achieved by glucosinolates (GLs) from Brassica plants was recently reported. However, wider application of functional feeds based on GLs requires better knowledge of their positive and adverse effects. Methods Liver, distal kidney and muscle transcriptomes of salmon exposed to the extreme dose of GLs were profiled by microarray, while qPCR analysis followed up selected hepatic and renal responses under the extreme and moderate GLs dose during the L. salmonis challenge. Transcriptional analysis were complemented with measurements of organ indices, liver steatosis and plasma profiling, including indicators of cytolysis and bilirubin. Finally, the third trial was performed to quantify the effect of lower GLs doses on growth. Results The extreme GLs dose caused a decrease in hepatic fat deposition and growth, in line with microarray findings, which suggested tissue remodeling and reduction of cellular proliferation in the skeletal muscle and liver. Lower GLs inclusion levels in a follow-up trial did not show negative effects on growth. Microarray analysis of the distal kidney pointed to activation of anti-fibrotic responses under the overexposure. However, analyses of ALT, CK and AST enzymes in plasma provided no evidence of increased cytolysis and organ damage. Prevalent activation of phase-2 detoxification genes that occurred in all three tissues could be considered part of beneficial effects caused by the extreme dose of GLs. In addition, transcriptomic evidence suggested GLs-mediated iron and heme withdrawal response, including increased heme degradation in muscle (upregulation of heme oxygenase-1), decrease of its synthesis in liver (downregulation of porphobilinogen deaminase) and increased iron sequestration from blood (hepatic induction of hepcidin-1 and renal induction of intracellular storage protein ferritin). This response could be advantageous for salmon upon encountering lice, which depend on the host for the provision of iron carrying heme. Most of the hepatic genes studied by qPCR showed similar expression levels in fish exposed to GLs, lice and their combination, while renal induction of leptin suggested heightened stress by the combination of extreme dose of GLs and lice. High expression of interferonγ (cytokine considered organ-protective in mammalian kidney) was detected at the moderate GLs level. This fish also showed highest plasma bilirubin levels (degradation product of heme), and had lowest number of attached lice, further supporting hypothesis that making heme unavailable to lice could be part of an effective anti-parasitic strategy. Conclusions Modulation of detoxification and iron metabolism in Atlantic salmon tissues could be beneficial prior and during lice infestations. Investigation of anti-lice functional feeds based on low and moderate GLs inclusion levels thus deserves further attention. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1921-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stanko Skugor
- Cargill Innovation Center, Sea Lice Research Centre, Oslo, Norway.
| | - Helle Jodaa Holm
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, Sea Lice Research Centre, Oslo, Norway
| | | | - Jorge Pino
- Cargill Innovation Center, Puerto Montt, Chile
| | - Øystein Evensen
- Norwegian University of Life Sciences, Faculty of Veterinary Medicine and Biosciences, Sea Lice Research Centre, Oslo, Norway
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216
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Wales P, Schuberth CE, Aufschnaiter R, Fels J, García-Aguilar I, Janning A, Dlugos CP, Schäfer-Herte M, Klingner C, Wälte M, Kuhlmann J, Menis E, Hockaday Kang L, Maier KC, Hou W, Russo A, Higgs HN, Pavenstädt H, Vogl T, Roth J, Qualmann B, Kessels MM, Martin DE, Mulder B, Wedlich-Söldner R. Calcium-mediated actin reset (CaAR) mediates acute cell adaptations. eLife 2016; 5. [PMID: 27919320 PMCID: PMC5140269 DOI: 10.7554/elife.19850] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/14/2016] [Indexed: 12/24/2022] Open
Abstract
Actin has well established functions in cellular morphogenesis. However, it is not well understood how the various actin assemblies in a cell are kept in a dynamic equilibrium, in particular when cells have to respond to acute signals. Here, we characterize a rapid and transient actin reset in response to increased intracellular calcium levels. Within seconds of calcium influx, the formin INF2 stimulates filament polymerization at the endoplasmic reticulum (ER), while cortical actin is disassembled. The reaction is then reversed within a few minutes. This Calcium-mediated actin reset (CaAR) occurs in a wide range of mammalian cell types and in response to many physiological cues. CaAR leads to transient immobilization of organelles, drives reorganization of actin during cell cortex repair, cell spreading and wound healing, and induces long-lasting changes in gene expression. Our findings suggest that CaAR acts as fundamental facilitator of cellular adaptations in response to acute signals and stress. DOI:http://dx.doi.org/10.7554/eLife.19850.001 Our skeleton plays a vital role in giving shape and structure to our body, it also allows us to make coordinated movements. Similarly, each cell contains a microscopic network of structures and supports called the cytoskeleton that helps cells to adopt specific shapes and is crucial for them to move around. Unlike our skeleton, which is relatively unchanging, the cytoskeleton of each cell constantly changes and adapts to the specific needs of the cell. One part of the cytoskeleton is a dense, flexible meshwork of fibers called the cortex that lies just beneath the surface of the cell. The cortex is constructed using a protein called actin, and many of these proteins join together to form each fiber. When cells need to adapt rapidly to an injury or other sudden changes in their environment they activate a so-called stress response. This response often begins with a rapid increase in the amount of calcium ions inside a cell, which can then trigger changes in actin organization. However, it is not clear how cells under stress are able to globally remodel their actin cytoskeleton without compromising stability and integrity of the cortex. Wales, Schuberth, Aufschnaiter et al. used a range of mammalian cells to investigate how actin responds to stress signals. All cells responded to the resulting influx of calcium ions by deconstructing large parts of the actin cortex and simultaneously forming actin filaments near the center of the cell. Wales, Schuberth, Aufschnaiter et al. termed this response calcium-mediated actin reset (CaAR), as it lasted for only a few minutes before the actin cortex reformed. The experiments show that a protein called INF2 controls CaAR by rapidly removing actin from the cortex and forming new filaments near a cell compartment called the endoplasmic reticulum. CaAR allows cells to rapidly and drastically alter the cortex in response to stress. The experiments also show that this sudden shift in actin can change the activity of certain genes, leading to longer-term effects on the cell. The findings of Wales, Schuberth, Aufschnaiter et al. suggest that calcium ions globally regulate the actin cytoskeleton and hence cell shape and movement under stress. This could be relevant for many important processes and conditions such as wound healing, inflammation and cancer. A future challenge will be to understand the role of CaAR in these processes. DOI:http://dx.doi.org/10.7554/eLife.19850.002
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Affiliation(s)
- Pauline Wales
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christian E Schuberth
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Roland Aufschnaiter
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Johannes Fels
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | | | - Annette Janning
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christopher P Dlugos
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany.,Medical Clinic D, University Clinic of Muenster, Muenster, Germany
| | - Marco Schäfer-Herte
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Christoph Klingner
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany.,AG Molecular Mechanotransduction, Max Planck Institute of Biochemistry, Munich, Germany
| | - Mike Wälte
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Julian Kuhlmann
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Ekaterina Menis
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Laura Hockaday Kang
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
| | - Kerstin C Maier
- Department of Biochemistry, University of Munich, Munich, Germany
| | - Wenya Hou
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Antonella Russo
- Institute of Immunology, University of Münster, Münster, Germany
| | - Henry N Higgs
- Department of Biochemistry, Dartmouth Medical School, Hanover, United States
| | | | - Thomas Vogl
- Institute of Immunology, University of Münster, Münster, Germany
| | - Johannes Roth
- Institute of Immunology, University of Münster, Münster, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Michael M Kessels
- Institute of Biochemistry I, Friedrich Schiller University Jena, Jena, Germany
| | - Dietmar E Martin
- Department of Biochemistry, University of Munich, Munich, Germany
| | - Bela Mulder
- Theory of Biological Matter, FOM Institute AMOLF, Amsterdam, Netherlands
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, University of Muenster, Muenster, Germany.,Cells-In-Motion Cluster of Excellence (EXC1003 - CiM), University of Münster, Muenster, Germany
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217
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Belyy A, Raoux-Barbot D, Saveanu C, Namane A, Ogryzko V, Worpenberg L, David V, Henriot V, Fellous S, Merrifield C, Assayag E, Ladant D, Renault L, Mechold U. Actin activates Pseudomonas aeruginosa ExoY nucleotidyl cyclase toxin and ExoY-like effector domains from MARTX toxins. Nat Commun 2016; 7:13582. [PMID: 27917880 PMCID: PMC5150216 DOI: 10.1038/ncomms13582] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/13/2016] [Indexed: 12/15/2022] Open
Abstract
The nucleotidyl cyclase toxin ExoY is one of the virulence factors injected by the Pseudomonas aeruginosa type III secretion system into host cells. Inside cells, it is activated by an unknown eukaryotic cofactor to synthesize various cyclic nucleotide monophosphates. ExoY-like adenylate cyclases are also found in Multifunctional-Autoprocessing Repeats-in-ToXin (MARTX) toxins produced by various Gram-negative pathogens. Here we demonstrate that filamentous actin (F-actin) is the hitherto unknown cofactor of ExoY. Association with F-actin stimulates ExoY activity more than 10,000 fold in vitro and results in stabilization of actin filaments. ExoY is recruited to actin filaments in transfected cells and alters F-actin turnover. Actin also activates an ExoY-like adenylate cyclase MARTX effector domain from Vibrio nigripulchritudo. Finally, using a yeast genetic screen, we identify actin mutants that no longer activate ExoY. Our results thus reveal a new sub-group within the class II adenylyl cyclase family, namely actin-activated nucleotidyl cyclase (AA-NC) toxins.
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Affiliation(s)
- Alexander Belyy
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
- Department of Bacterial Infections, Gamaleya Research Center, Moscow 123098, Russia
| | - Dorothée Raoux-Barbot
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Cosmin Saveanu
- Institut Pasteur, CNRS UMR3525, Génétique des Interactions Macromoléculaires, Département de Génomes et Génétique, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Abdelkader Namane
- Institut Pasteur, CNRS UMR3525, Génétique des Interactions Macromoléculaires, Département de Génomes et Génétique, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Vasily Ogryzko
- Institut Gustave Roussy, CNRS UMR 8126, Unité de Signaling, Nuclei and Innovations in Oncology, 94805 Villejuif, France
| | - Lina Worpenberg
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Violaine David
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Veronique Henriot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Souad Fellous
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Christien Merrifield
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Elodie Assayag
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Daniel Ladant
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
| | - Louis Renault
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France
| | - Undine Mechold
- Institut Pasteur, CNRS UMR3528, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 25-28 rue du Docteur Roux, 75724 Paris cedex 15, France
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218
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Nicovich PR, Janco M, Sobey T, Gajwani M, Obeidy P, Whan R, Gaus K, Gunning PW, Coster AC, Böcking T. Effect of surface chemistry on tropomyosin binding to actin filaments on surfaces. Cytoskeleton (Hoboken) 2016; 73:729-738. [PMID: 27783462 DOI: 10.1002/cm.21342] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 01/29/2023]
Abstract
Reconstitution of actin filaments on surfaces for observation of filament-associated protein dynamics by fluorescence microscopy is currently an exciting field in biophysics. Here we examine the effects of attaching actin filaments to surfaces on the binding and dissociation kinetics of a fluorescence-labeled tropomyosin, a rod-shaped protein that forms continuous strands wrapping around the actin filament. Two attachment modalities of the actin to the surface are explored: where the actin filament is attached to the surface at multiple points along its length; and where the actin filament is attached at one end and aligned parallel to the surface by buffer flow. To facilitate analysis of actin-binding protein dynamics, we have developed a software tool for the viewing, tracing and analysis of filaments and co-localized species in noisy fluorescence timelapse images. Our analysis shows that the interaction of tropomyosin with actin filaments is similar for both attachment modalities. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Philip R Nicovich
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Miro Janco
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Tom Sobey
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Mehul Gajwani
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Peyman Obeidy
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Renee Whan
- Biomedical Imaging Facility, University of New South Wales, Sydney, Australia
| | - Katharina Gaus
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Adelle Cf Coster
- School of Mathematics and Statistics, University of New South Wales, Sydney, Australia
| | - Till Böcking
- ARC Centre of Excellence in Advanced Molecular Imaging and EMBL Australia Node in Single Molecule Science, School of Medical Sciences, University of New South Wales, Sydney, Australia
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219
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Jiang S, Ghoshdastider U, Narita A, Popp D, Robinson RC. Structural complexity of filaments formed from the actin and tubulin folds. Commun Integr Biol 2016; 9:e1242538. [PMID: 28042378 PMCID: PMC5193048 DOI: 10.1080/19420889.2016.1242538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 11/09/2022] Open
Abstract
From yeast to man, an evolutionary distance of 1.3 billion years, the F-actin filament structure has been conserved largely in line with the 94% sequence identity. The situation is entirely different in bacteria. In comparison to eukaryotic actins, the bacterial actin-like proteins (ALPs) show medium to low levels of sequence identity. This is extreme in the case of the ParM family of proteins, which often display less than 20% identity. ParMs are plasmid segregation proteins that form the polymerizing motors that propel pairs of plasmids to the extremities of a cell prior to cell division, ensuring faithful inheritance of the plasmid. Recently, exotic ParM filament structures have been elucidated that show ParM filament geometries are not limited to the standard polar pair of strands typified by actin. Four-stranded non-polar ParM filaments existing as open or closed nanotubules are found in Clostridium tetani and Bacillus thuringiensis, respectively. These diverse architectures indicate that the actin fold is capable of forming a large variety of filament morphologies, and that the conception of the “actin” filament has been heavily influenced by its conservation in eukaryotes. Here, we review the history of the structure determination of the eukaryotic actin filament to give a sense of context for the discovery of the new ParM filament structures. We describe the novel ParM geometries and predict that even more complex actin-like filaments may exist in bacteria. Finally, we compare the architectures of filaments arising from the actin and tubulin folds and conclude that the basic units possess similar properties that can each form a range of structures. Thus, the use of the actin fold in microfilaments and the tubulin fold for microtubules likely arose from a wider range of filament possibilities, but became entrenched as those architectures in early eukaryotes.
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Affiliation(s)
- Shimin Jiang
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Umesh Ghoshdastider
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Akihiro Narita
- Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences , Furo-cho , Chikusa-ku, Nagoya, Japan
| | - David Popp
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research) , Biopolis, Singapore
| | - Robert C Robinson
- Institute of Molecular and Cell Biology, ASTAR (Agency for Science, Technology and Research), Biopolis, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore; Lee Kong Chan School of Medicine, Singapore
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220
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Expression of profilin in Trypanosoma cruzi and identification of some of its ligands. Biochem Biophys Res Commun 2016; 480:709-714. [DOI: 10.1016/j.bbrc.2016.10.044] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/15/2016] [Indexed: 12/31/2022]
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221
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Chakrabarti KR, Whipple RA, Boggs AE, Hessler LK, Bhandary L, Vitolo MI, Thompson K, Martin SS. Pharmacologic regulation of AMPK in breast cancer affects cytoskeletal properties involved with microtentacle formation and re-attachment. Oncotarget 2016; 6:36292-307. [PMID: 26431377 PMCID: PMC4742178 DOI: 10.18632/oncotarget.5345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/11/2015] [Indexed: 01/20/2023] Open
Abstract
The presence of tumor cells in the circulation is associated with a higher risk of metastasis in patients with breast cancer. Circulating breast tumor cells use tubulin-based structures known as microtentacles (McTNs) to re-attach to endothelial cells and arrest in distant organs. McTN formation is dependent on the opposing cytoskeletal forces of stable microtubules and the actin network. AMP-activated protein kinase (AMPK) is a cellular metabolic regulator that can alter actin and microtubule organization in epithelial cells. We report that AMPK can regulate the cytoskeleton of breast cancer cells in both attached and suspended conditions. We tested the effects of AMPK on microtubule stability and the actin-severing protein, cofilin. AMPK inhibition with compound c increased both microtubule stability and cofilin activation, which also resulted in higher McTN formation and re-attachment. Conversely, AMPK activation with A-769662 decreased microtubule stability and cofilin activation with concurrent decreases in McTN formation and cell re-attachment. This data shows for the first time that AMPK shifts the balance of cytoskeletal forces in suspended breast cancer cells, which affect their ability to form McTNs and re-attach. These results support a model where AMPK activators may be used therapeutically to reduce the metastatic efficiency of breast tumor cells.
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Affiliation(s)
- Kristi R Chakrabarti
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rebecca A Whipple
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Amanda E Boggs
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lindsay K Hessler
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Lekhana Bhandary
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Michele I Vitolo
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Keyata Thompson
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Stuart S Martin
- University of Maryland School of Medicine, Marlene and Stewart Greenebaum National Cancer Institute Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA.,Graduate Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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222
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Spectroscopic characterization of the effect of mouse twinfilin-1 on actin filaments at different pH values. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 164:276-282. [PMID: 27718419 DOI: 10.1016/j.jphotobiol.2016.09.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 09/26/2016] [Accepted: 09/30/2016] [Indexed: 11/22/2022]
Abstract
The effect of mammalian twinfilin-1 on the structure and dynamics of actin filaments were studied with steady state fluorescence spectroscopy, total internal reflection fluorescence microscopy and differential scanning calorimetry techniques. It was proved before that the eukaryotic budding yeast twinfilin-1 can efficiently bind and severe actin filaments in vitro at low pH values. In the present work steady-state anisotropy measurements revealed that twinfilin can bind efficiently to F-actin. Dilution-induced depolymerization assay proved that mammalian twinfilin-1 has an actin filament severing activity. This severing activity was more pronounced at low pH values. Total internal reflection fluorescence microscopy measurements could support the severing activity of mouse twinfilin-1. The average rate of depolymerization was more apparent at low pH values. The differential scanning calorimetry measurements demonstrated that mammalian twinfilin-1 could reduce the stiffness within the actin filaments before the detachment of the actin protomers. The structural and dynamic reorganization of actin can support the twinfilin-1 induced separation of actin protomers. The measured data indicated that mammalian twinfilin-1 was able to accelerate the monomers dissociation and/or sever the filaments effectively at low pH values. It was concluded that twinfilin-1 can affect the F-actin in biological processes or under stress situations when the pH is markedly under the physiological level.
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223
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A Genome-Wide Association Study Identifies Multiple Regions Associated with Head Size in Catfish. G3-GENES GENOMES GENETICS 2016; 6:3389-3398. [PMID: 27558670 PMCID: PMC5068958 DOI: 10.1534/g3.116.032201] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Skull morphology is fundamental to evolution and the biological adaptation of species to their environments. With aquaculture fish species, head size is also important for economic reasons because it has a direct impact on fillet yield. However, little is known about the underlying genetic basis of head size. Catfish is the primary aquaculture species in the United States. In this study, we performed a genome-wide association study using the catfish 250K SNP array with backcross hybrid catfish to map the QTL for head size (head length, head width, and head depth). One significantly associated region on linkage group (LG) 7 was identified for head length. In addition, LGs 7, 9, and 16 contain suggestively associated regions for head length. For head width, significantly associated regions were found on LG9, and additional suggestively associated regions were identified on LGs 5 and 7. No region was found associated with head depth. Head size genetic loci were mapped in catfish to genomic regions with candidate genes involved in bone development. Comparative analysis indicated that homologs of several candidate genes are also involved in skull morphology in various other species ranging from amphibian to mammalian species, suggesting possible evolutionary conservation of those genes in the control of skull morphologies.
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Actin-Dependent Alterations of Dendritic Spine Morphology in Shankopathies. Neural Plast 2016; 2016:8051861. [PMID: 27795858 PMCID: PMC5067329 DOI: 10.1155/2016/8051861] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 08/30/2016] [Indexed: 12/11/2022] Open
Abstract
Shank proteins (Shank1, Shank2, and Shank3) act as scaffolding molecules in the postsynaptic density of many excitatory neurons. Mutations in SHANK genes, in particular SHANK2 and SHANK3, lead to autism spectrum disorders (ASD) in both human and mouse models. Shank3 proteins are made of several domains-the Shank/ProSAP N-terminal (SPN) domain, ankyrin repeats, SH3 domain, PDZ domain, a proline-rich region, and the sterile alpha motif (SAM) domain. Via various binding partners of these domains, Shank3 is able to bind and interact with a wide range of proteins including modulators of small GTPases such as RICH2, a RhoGAP protein, and βPIX, a RhoGEF protein for Rac1 and Cdc42, actin binding proteins and actin modulators. Dysregulation of all isoforms of Shank proteins, but especially Shank3, leads to alterations in spine morphogenesis, shape, and activity of the synapse via altering actin dynamics. Therefore, here, we highlight the role of Shank proteins as modulators of small GTPases and, ultimately, actin dynamics, as found in multiple in vitro and in vivo models. The failure to mediate this regulatory role might present a shared mechanism in the pathophysiology of autism-associated mutations, which leads to dysregulation of spine morphogenesis and synaptic signaling.
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225
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Haga RB, Ridley AJ. Rho GTPases: Regulation and roles in cancer cell biology. Small GTPases 2016; 7:207-221. [PMID: 27628050 PMCID: PMC5129894 DOI: 10.1080/21541248.2016.1232583] [Citation(s) in RCA: 314] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 08/26/2016] [Accepted: 08/29/2016] [Indexed: 02/08/2023] Open
Abstract
Rho GTPases are well known for their roles in regulating cell migration, and also contribute to a variety of other cellular responses. They are subdivided into 2 groups: typical and atypical. The typical Rho family members, including RhoA, Rac1 and Cdc42, cycle between an active GTP-bound and inactive GDP-bound conformation, and are regulated by GEFs, GAPs and GDIs, whereas atypical Rho family members have amino acid substitutions that alter their ability to interact with GTP/GDP and hence are regulated by different mechanisms. Both typical and atypical Rho GTPases contribute to cancer progression. In a few cancers, RhoA or Rac1 are mutated, but in most cancers expression levels and/or activity of Rho GTPases is altered. Rho GTPase signaling could therefore be therapeutically targeted in cancer treatment.
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Affiliation(s)
- Raquel B. Haga
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - Anne J. Ridley
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
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226
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Utilization of paramagnetic relaxation enhancements for structural analysis of actin-binding proteins in complex with actin. Sci Rep 2016; 6:33690. [PMID: 27654858 PMCID: PMC5031973 DOI: 10.1038/srep33690] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/23/2016] [Indexed: 11/08/2022] Open
Abstract
Actin cytoskeleton dynamics are controlled by various actin binding proteins (ABPs) that modulate the polymerization of the monomeric G-actin and the depolymerization of filamentous F-actin. Although revealing the structures of the actin/ABP complexes is crucial to understand how the ABPs regulate actin dynamics, the X-ray crystallography and cryoEM methods are inadequate to apply for the ABPs that interact with G- or F-actin with lower affinity or multiple binding modes. In this study, we aimed to establish the alternative method to build a structural model of G-actin/ABP complexes, utilizing the paramagnetic relaxation enhancement (PRE) experiments. Thymosin β4 (Tβ4) was used as a test case for validation, since its structure in complex with G-actin was reported recently. Recombinantly expressed G-actin, containing a cysteine mutation, was conjugated with a nitroxyl spin label at the specific site. Based on the intensity ratio of the 1H-15N HSQC spectra of Tβ4 in the complex with G-actin in the paramagnetic and diamagnetic states, the distances between the amide groups of Tβ4 and the spin label of G-actin were estimated. Using the PRE-derived distance constraints, we were able to compute a well-converged docking structure of the G-actin/Tβ4 complex that shows great accordance with the reference structure.
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227
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De novo sequencing, assembly and analysis of eight different transcriptomes from the Malayan pangolin. Sci Rep 2016; 6:28199. [PMID: 27618997 PMCID: PMC5020319 DOI: 10.1038/srep28199] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 06/01/2016] [Indexed: 01/06/2023] Open
Abstract
Pangolins are scale-covered mammals, containing eight endangered species. Maintaining pangolins in captivity is a significant challenge, in part because little is known about their genetics. Here we provide the first large-scale sequencing of the critically endangered Manis javanica transcriptomes from eight different organs using Illumina HiSeq technology, yielding ~75 Giga bases and 89,754 unigenes. We found some unigenes involved in the insect hormone biosynthesis pathway and also 747 lipids metabolism-related unigenes that may be insightful to understand the lipid metabolism system in pangolins. Comparative analysis between M. javanica and other mammals revealed many pangolin-specific genes significantly over-represented in stress-related processes, cell proliferation and external stimulus, probably reflecting the traits and adaptations of the analyzed pregnant female M. javanica. Our study provides an invaluable resource for future functional works that may be highly relevant for the conservation of pangolins.
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228
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The Candida albicans fimbrin Sac6 regulates oxidative stress response (OSR) and morphogenesis at the transcriptional level. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:2255-66. [DOI: 10.1016/j.bbamcr.2016.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 05/27/2016] [Accepted: 06/02/2016] [Indexed: 12/30/2022]
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229
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Reithmann E, Reese L, Frey E. Nonequilibrium Diffusion and Capture Mechanism Ensures Tip Localization of Regulating Proteins on Dynamic Filaments. PHYSICAL REVIEW LETTERS 2016; 117:078102. [PMID: 27564001 DOI: 10.1103/physrevlett.117.078102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Indexed: 06/06/2023]
Abstract
Diffusive motion of regulatory enzymes on biopolymers with eventual capture at a reaction site is a common feature in cell biology. Using a lattice gas model we study the impact of diffusion and capture for a microtubule polymerase and a depolymerase. Our results show that the capture mechanism localizes the proteins and creates large-scale spatial correlations. We develop an analytic approximation that globally accounts for relevant correlations and yields results that are in excellent agreement with experimental data. Our results show that diffusion and capture operates most efficiently at cellular enzyme concentrations which points to in vivo relevance.
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Affiliation(s)
- Emanuel Reithmann
- Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, 80333 München, Germany
| | - Louis Reese
- Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, 80333 München, Germany
| | - Erwin Frey
- Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München, Theresienstrasse 37, 80333 München, Germany
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230
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Khan S, Conte I, Carter T, Bayer KU, Molloy JE. Multiple CaMKII Binding Modes to the Actin Cytoskeleton Revealed by Single-Molecule Imaging. Biophys J 2016; 111:395-408. [PMID: 27463141 PMCID: PMC4968397 DOI: 10.1016/j.bpj.2016.06.007] [Citation(s) in RCA: 24] [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: 12/16/2015] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 11/22/2022] Open
Abstract
Localization of the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) to dendritic spine synapses is determined in part by the actin cytoskeleton. We determined binding of GFP-tagged CaMKII to tag-RFP-labeled actin cytoskeleton within live cells using total internal reflection fluorescence microscopy and single-molecule tracking. Stepwise photobleaching showed that CaMKII formed oligomeric complexes. Photoactivation experiments demonstrated that diffusion out of the evanescent field determined the track lifetimes. Latrunculin treatment triggered a coupled loss of actin stress fibers and the colocalized, long-lived CaMKII tracks. The CaMKIIα (α) isoform, which was previously thought to lack F-actin interactions, also showed binding, but this was threefold weaker than that observed for CaMKIIβ (β). The βE' splice variant bound more weakly than α, showing that binding by β depends critically on the interdomain linker. The mutations βT287D and αT286D, which mimic autophosphorylation states, also abolished F-actin binding. Autophosphorylation triggers autonomous CaMKII activity, but does not impair GluN2B binding, another important synaptic protein interaction of CaMKII. The CaMKII inhibitor tatCN21 or CaMKII mutations that inhibit GluN2B association by blocking binding of ATP (βK43R and αK42M) or Ca(2+)/calmodulin (βA303R) had no effect on the interaction with F-actin. These results provide the first rationale for the reduced synaptic spine localization of the αT286D mutant, indicating that transient F-actin binding contributes to the synaptic localization of the CaMKIIα isoform. The track lifetime distributions had a stretched exponential form consistent with a heterogeneously diffusing population. This heterogeneity suggests that CaMKII adopts different F-actin binding modes, which is most easily rationalized by multiple subunit contacts between the CaMKII dodecamer and the F-actin cytoskeleton that stabilize the initial weak (micromolar) monovalent interaction.
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Affiliation(s)
- Shahid Khan
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, California.
| | - Ianina Conte
- Cardiovascular and Cell Science Research Institute, St. George's University of London, London, UK
| | - Tom Carter
- Cell Biology and Genetics, St. George's University of London, London, UK
| | - K Ulrich Bayer
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado
| | - Justin E Molloy
- The Francis Crick Institute, Mill Hill Laboratory, London, UK
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231
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F-actin dampens NLRP3 inflammasome activity via Flightless-I and LRRFIP2. Sci Rep 2016; 6:29834. [PMID: 27431477 PMCID: PMC4949445 DOI: 10.1038/srep29834] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/22/2016] [Indexed: 01/12/2023] Open
Abstract
NLRP3 and ASC are able to form a large multimeric complex called inflammasome in response to a number danger signals. The NLRP3 inflammasome is required for the activation of caspase-1 and subsequent maturation of pro-IL-1β into active IL-1β. Although the mechanisms regulating the formation and activity of NLRP3 inflammasome are yet not fully elucidated, data suggest that the assembly of NLRP3 inflammasome requires microtubules to induce the proximity of ASC and NLRP3. In this study we show that microfilaments (F-actin) inhibit NLRP3 inflammasome activity and interact with NLRP3 and ASC. We demonstrate that the inhibition depends on the actin polymerization state but not on the active polymerization process. In ATP- or nigericin-activated macrophages, our data further indicate that Flightless-I (FliI) and leucine-rich repeat FliI-interaction protein 2 (LRRFIP2) are required for the co-localization of NLRP3, ASC and F-actin. We also established that the ability of Ca2+ to accentuate the activity of NLRP3 inflammasome is abrogated in FliI- and LRRFIP2-knockdown macrophages, suggesting that Ca2+ signaling requires the presence of FliI and LRRFIP2. Accordingly, we observed that Ca2+/FliI-dependent severing of F-actin suppresses F-actin/FliI/LRRFIP2-dependent NLRP3 inflammasome inhibition leading to increase IL-1β production. Altogether, our results unveil a new function of F-actin in the regulation of NLRP3 inflammasome activity strengthening the importance of cytoskeleton in the regulation of inflammation.
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232
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Lim J, Ehsanipour A, Hsu JJ, Lu J, Pedego T, Wu A, Walthers CM, Demer LL, Seidlits SK, Tintut Y. Inflammation Drives Retraction, Stiffening, and Nodule Formation via Cytoskeletal Machinery in a Three-Dimensional Culture Model of Aortic Stenosis. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2378-89. [PMID: 27392969 DOI: 10.1016/j.ajpath.2016.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/27/2016] [Accepted: 05/05/2016] [Indexed: 12/26/2022]
Abstract
In calcific aortic valve disease, the valve cusps undergo retraction, stiffening, and nodular calcification. The inflammatory cytokine, tumor necrosis factor (TNF)-α, contributes to valve disease progression; however, the mechanisms of its actions on cusp retraction and stiffening are unclear. We investigated effects of TNF-α on murine aortic valvular interstitial cells (VICs) within three-dimensional, free-floating, compliant, collagen hydrogels, simulating their natural substrate and biomechanics. TNF-α increased retraction (percentage of diameter), stiffness, and formation of macroscopic, nodular structures with calcification in the VIC-laden hydrogels. The effects of TNF-α were attenuated by blebbistatin inhibition of myosin II-mediated cytoskeletal contraction. Inhibition of actin polymerization with cytochalasin-D, but not inhibition of Rho kinase with Y27632, blocked TNF-α-induced retraction in three-dimensional VIC hydrogels, suggesting that actin stress fibers mediate TNF-α-induced effects. In the hydrogels, inhibitors of NF-κB blocked TNF-α-induced retraction, whereas simultaneous inhibition of c-Jun N-terminal kinase was required to block TNF-α-induced stiffness. TNF-α also significantly increased collagen deposition, as visualized by Masson's trichrome staining, and up-regulated mRNA expression of discoidin domain receptor tyrosine kinase 2, fibronectin, and α-smooth muscle actin. In human aortic valves, calcified cusps were stiffer and had more collagen deposition than noncalcified cusps. These findings suggest that inflammation, through stimulation of cytoskeletal contractile activity, may be responsible for valvular cusp retraction, stiffening, and formation of calcified nodules.
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Affiliation(s)
- Jina Lim
- Department of Pediatrics, University of California, Los Angeles, Los Angeles, California
| | - Arshia Ehsanipour
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Jeffrey J Hsu
- Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Jinxiu Lu
- Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Taylor Pedego
- Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Alexander Wu
- Department of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Chris M Walthers
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Linda L Demer
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California; Department of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Physiology, University of California, Los Angeles, Los Angeles, California
| | - Stephanie K Seidlits
- Department of Bioengineering, University of California, Los Angeles, Los Angeles, California
| | - Yin Tintut
- Department of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Physiology, University of California, Los Angeles, Los Angeles, California; Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, California.
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233
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Tropomodulin-3 is essential in asymmetric division during mouse oocyte maturation. Sci Rep 2016; 6:29204. [PMID: 27374327 PMCID: PMC4931587 DOI: 10.1038/srep29204] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/16/2016] [Indexed: 11/08/2022] Open
Abstract
The dynamic polymerization and depolymerization of actin filaments is essential for various cellular processes such as cell migration, rotation, cytokinesis, and mammalian oocyte maturation. Tropomodulin 3 (Tmod3) binds to the slow-growing (pointed) ends of the actin filament, thereby protecting the filament from depolymerization. However, the roles of Tmod3 in mammalian oocyte maturation remain elusive. Tmod3 mRNA and protein is present at all stages of mouse oocyte maturation. Tmod3 protein is mainly localized in the cytoplasm and appears enriched near the chromosome during maturation. By knocking down or ectopically overexpressing Tmod3, we confirmed that Tmod3 regulate the level of the intracytoplasmic actin mesh and asymmetric spindle migration. Expression of N-terminal Tmod3 (correspond to 1–155 amino acids), which contains the tropomyosin-binding site, results in decreased density of the actin mesh, thereby demonstrating the importance of the interaction between tropomyosin and tropomodulin for the maintenance of the actin mesh. Taken together, these findings indicate that Tmod3 plays crucial roles in oocyte maturation, presumably by protecting the actin filament from depolymerization and thereby controlling the density of the cytoplasmic actin mesh.
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234
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Li N, Lee WM, Cheng CY. Overexpression of plastin 3 in Sertoli cells disrupts actin microfilament bundle homeostasis and perturbs the tight junction barrier. SPERMATOGENESIS 2016; 6:e1206353. [PMID: 27559491 DOI: 10.1080/21565562.2016.1206353] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 06/07/2016] [Accepted: 06/20/2016] [Indexed: 02/08/2023]
Abstract
Throughout the epithelial cycle of spermatogenesis, actin microfilaments arranged as bundles near the Sertoli cell plasma membrane at the Sertoli cell-cell interface that constitute the blood-testis barrier (BTB) undergo extensive re-organization by converting between bundled and unbundled/branched configuration to give plasticity to the F-actin network. This is crucial to accommodate the transport of preleptotene spermatocytes across the BTB. Herein, we sought to examine changes in the actin microfilament organization at the Sertoli cell BTB using an in vitro model since Sertoli cells cultured in vitro is known to establish a functional tight junction (TJ)-permeability barrier that mimics the BTB in vivo. Plastin 3, a known actin microfilament cross-linker and bundling protein, when overexpressed in Sertoli cells using a mammalian expression vector pCI-neo was found to perturb the Sertoli cell TJ-barrier function even though its overexpression increased the overall actin bundling activity in these cells. Furthermore, plastin 3 overexpression also perturbed the localization and distribution of BTB-associated proteins, such as occludin-ZO1 and N-cadherin-β-catenin, this thus destabilized the barrier function. Collectively, these data illustrate that a delicate balance of actin microfilaments between organized in bundles vs. an unbundled/branched configuration is crucial to confer the homeostasis of the BTB and its integrity.
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Affiliation(s)
- Nan Li
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research , New York, NY, USA
| | - Will M Lee
- School of Biological Sciences, University of Hong Kong , Hong Kong, China
| | - C Yan Cheng
- The Mary M. Wohlford Laboratory for Male Contraceptive Research, Center for Biomedical Research , New York, NY, USA
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235
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Wang YH, Bucki R, Janmey PA. Cholesterol-Dependent Phase-Demixing in Lipid Bilayers as a Switch for the Activity of the Phosphoinositide-Binding Cytoskeletal Protein Gelsolin. Biochemistry 2016; 55:3361-9. [PMID: 27224309 DOI: 10.1021/acs.biochem.5b01363] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The lateral distribution of phosphatidylinositol 4,5-bisphosphate (PIP2) in lipid bilayers is affected both by divalent cation-mediated attractions and cholesterol-dependent phase demixing. The effects of lateral redistribution of PIP2 within a membrane on PIP2-protein interactions are explored with an N-terminal fragment of gelsolin (NtGSN) that severs actin in a Ca(2+)-insensitive manner. The extent of NtGSN inhibition by PIP2-containing large unilamellar vesicles (LUVs) depends on the lateral organization of the membrane as quantified by an actin-severing assay. At a fixed PIP2 mole fraction, the inhibition is largely enhanced by the segregation of liquid ordered/liquid disordered (Lo/Ld) phases that is induced by altering either cholesterol content or temperature, whereas the presence of Ca(2+) only slightly improves the inhibition. Inhibition of gelsolin induced by demixed LUVs is more effective with decreasing temperature, coincident with increasing membrane order as determined by Laurdan generalized polarization and is reversible as the temperature increases. This result suggests that PIP2-mediated inhibition of gelsolin function depends not only on changes in global concentration but also on lateral distribution of PIP2. These observations imply that gelsolin, and perhaps other PIP2-regulated proteins, can be activated or inactivated by the formation of nanodomains or clusters without changing PIP2 bulk concentration in the cell membrane.
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Affiliation(s)
- Yu-Hsiu Wang
- Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104, United States
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236
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Chen X, Cui J, Sun H, Müllner M, Yan Y, Noi KF, Ping Y, Caruso F. Analysing intracellular deformation of polymer capsules using structured illumination microscopy. NANOSCALE 2016; 8:11924-31. [PMID: 27241620 DOI: 10.1039/c6nr02151d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Understanding the behaviour of therapeutic carriers is important in elucidating their mechanism of action and how they are processed inside cells. Herein we examine the intracellular deformation of layer-by-layer assembled polymer capsules using super-resolution structured illumination microscopy (SIM). Spherical- and cylindrical-shaped capsules were studied in three different cell lines, namely HeLa (human epithelial cell line), RAW264.7 (mouse macrophage cell line) and differentiated THP-1 (human monocyte-derived macrophage cell line). We observed that the deformation of capsules was dependent on cell line, but independent of capsule shape. This suggests that the mechanical forces, which induce capsule deformation during cell uptake, vary between cell lines, indicating that the capsules are exposed to higher mechanical forces in HeLa cells, followed by RAW264.7 and then differentiated THP-1 cells. Our study demonstrates the use of super-resolution SIM in analysing intracellular capsule deformation, offering important insights into the cellular processing of drug carriers in cells and providing fundamental knowledge of intracellular mechanobiology. Furthermore, this study may aid in the design of novel drug carriers that are sensitive to deformation for enhanced drug release properties.
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Affiliation(s)
- Xi Chen
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Jiwei Cui
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Huanli Sun
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Markus Müllner
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Yan Yan
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Ka Fung Noi
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Yuan Ping
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Frank Caruso
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, and the Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, Victoria 3010, Australia.
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237
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Gray KT, Suchowerska AK, Bland T, Colpan M, Wayman G, Fath T, Kostyukova AS. Tropomodulin isoforms utilize specific binding functions to modulate dendrite development. Cytoskeleton (Hoboken) 2016; 73:316-28. [PMID: 27126680 DOI: 10.1002/cm.21304] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 12/18/2022]
Abstract
Tropomodulins (Tmods) cap F-actin pointed ends and have altered expression in the brain in neurological diseases. The function of Tmods in neurons has been poorly studied and their role in neurological diseases is entirely unknown. In this article, we show that Tmod1 and Tmod2, but not Tmod3, are positive regulators of dendritic complexity and dendritic spine morphology. Tmod1 increases dendritic branching distal from the cell body and the number of filopodia/thin spines. Tmod2 increases dendritic branching proximal to the cell body and the number of mature dendritic spines. Tmods utilize two actin-binding sites and two tropomyosin (Tpm)-binding sites to cap F-actin. Overexpression of Tmods with disrupted Tpm-binding sites indicates that Tmod1 and Tmod2 differentially utilize their Tpm- and actin-binding sites to affect morphology. Disruption of Tmod1's Tpm-binding sites abolished the overexpression phenotype. In contrast, overexpression of the mutated Tmod2 caused the same phenotype as wild type overexpression. Proximity ligation assays indicate that the mutated Tmods are shuttled similarly to wild type Tmods. Our data begins to uncover the roles of Tmods in neural development and the mechanism by which Tmods alter neural morphology. These observations in combination with altered Tmod expression found in several neurological diseases also suggest that dysregulation of Tmod expression may be involved in the pathology of these diseases. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kevin T Gray
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Alexandra K Suchowerska
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Tyler Bland
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Mert Colpan
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
| | - Gary Wayman
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Thomas Fath
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Alla S Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington
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238
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Pernier J, Shekhar S, Jegou A, Guichard B, Carlier MF. Profilin Interaction with Actin Filament Barbed End Controls Dynamic Instability, Capping, Branching, and Motility. Dev Cell 2016; 36:201-14. [PMID: 26812019 PMCID: PMC4729542 DOI: 10.1016/j.devcel.2015.12.024] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/09/2015] [Accepted: 12/22/2015] [Indexed: 12/22/2022]
Abstract
Cell motility and actin homeostasis depend on the control of polarized growth of actin filaments. Profilin, an abundant regulator of actin dynamics, supports filament assembly at barbed ends by binding G-actin. Here, we demonstrate how, by binding and destabilizing filament barbed ends at physiological concentrations, profilin also controls motility, cell migration, and actin homeostasis. Profilin enhances filament length fluctuations. Profilin competes with Capping Protein at barbed ends, which generates a lower amount of profilin-actin than expected if barbed ends were tightly capped. Profilin competes with barbed end polymerases, such as formins and VopF, and inhibits filament branching by WASP-Arp2/3 complex by competition for filament barbed ends, accounting for its as-yet-unknown effects on motility and metastatic cell migration observed in this concentration range. In conclusion, profilin is a major coordinator of polarized growth of actin filaments, controlled by competition between barbed end cappers, trackers, destabilizers, and filament branching machineries. The binding of profilin to barbed ends accounts for its effects on cell migration Profilin enhances length fluctuations of actin filaments by destabilizing barbed ends Profilin competes with capping protein at filament barbed ends Profilin competes with polymerases and filament branching machineries at barbed ends
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Affiliation(s)
- Julien Pernier
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Shashank Shekhar
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Antoine Jegou
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Bérengère Guichard
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility Group, I2BC, CNRS, Gif-sur-Yvette 91198, France.
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239
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Wu MC, Forbes JG, Wang K. Disorder profile of nebulin encodes a vernierlike position sensor for the sliding thin and thick filaments of the skeletal muscle sarcomere. Phys Rev E 2016; 93:062406. [PMID: 27415297 DOI: 10.1103/physreve.93.062406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Indexed: 06/06/2023]
Abstract
Nebulin is an about 1μm long intrinsically disordered scaffold for the thin filaments of skeletal muscle sarcomere. It is a multifunctional elastic protein that wraps around actin filament, stabilizes thin filaments, and regulates Ca-dependent actomyosin interactions. This study investigates whether the disorder profile of nebulin might encode guidelines for thin and thick filament interactions in the sarcomere of the skeletal muscle. The question was addressed computationally by analyzing the predicted disorder profile of human nebulin (6669 residues, ∼200 actin-binding repeats) by pondr and the periodicity of the A-band stripes (reflecting the locations of myosin-associated proteins) in the electron micrographs of the sarcomere. Using the detrended fluctuation analysis, a scale factor for the A-band stripe image data with respect to the nebulin disorder profile was determined to make the thin and thick filaments aligned to have maximum correlation. The empirical mode decomposition method was then applied to identify hidden periodicities in both the nebulin disorder profile and the rescaled A-band data. The decomposition reveals three characteristic length scales (45 nm, 100 nm, and 200 nm) that are relevant for correlational analysis. The dynamical cross-correlation analyses with moving windows at various sarcomere lengths depict a vernierlike design for both periodicities, thus enabling nebulin to sense position and fine tune sarcomere overlap. This shows that the disorder profile of scaffolding proteins may encode a guideline for cellular architecture.
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Affiliation(s)
- Ming-Chya Wu
- Research Center for Adaptive Data Analysis, National Central University, Chungli, Taoyuan 32001, Taiwan
- Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | | | - Kuan Wang
- Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan
- Nanomedicine Program, and Institute of Biological Chemistry, Academia Sinica, Nankang, Taipei 11529, Taiwan
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240
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Renault L. Intrinsic, Functional, and Structural Properties of β-Thymosins and β-Thymosin/WH2 Domains in the Regulation and Coordination of Actin Self-Assembly Dynamics and Cytoskeleton Remodeling. VITAMINS AND HORMONES 2016; 102:25-54. [PMID: 27450729 DOI: 10.1016/bs.vh.2016.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
β-Thymosins are a family of heat-stable multifunctional polypeptides that are expressed as small proteins of about 5kDa (~45 amino acids) almost exclusively in multicellular animals. They were first isolated from the thymus. As full-length or truncated polypeptides, they appear to stimulate a broad range of extracellular activities in various signaling pathways, including tissue repair and regeneration, inflammation, cell migration, and immune defense. However, their cell surface receptors and structural mechanisms of regulations in these multiple pathways remain still poorly understood. Besides their extracellular activities, they belong to a larger family of small, intrinsically disordered actin-binding domains called WH2/β-thymosin domains that have been identified in more than 1800 multidomain proteins found in different taxonomic domains of life and involved in various actin-based motile processes including cell morphogenesis, motility, adhesions, tissue development, intracellular trafficking, or pathogen infections. This review briefly surveys the main recent findings to understand how these small, intrinsically disordered but functional domains can interact with many unrelated partners and can thus integrate and coordinate various intracellular activities in actin self-assembly dynamics and cell signaling pathways linked to their cytoskeleton remodeling.
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Affiliation(s)
- L Renault
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France.
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241
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nArgBP2 regulates excitatory synapse formation by controlling dendritic spine morphology. Proc Natl Acad Sci U S A 2016; 113:6749-54. [PMID: 27226294 DOI: 10.1073/pnas.1600944113] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Neural Abelson-related gene-binding protein 2 (nArgBP2) was originally identified as a protein that directly interacts with synapse-associated protein 90/postsynaptic density protein 95-associated protein 3 (SAPAP3), a postsynaptic scaffolding protein critical for the assembly of glutamatergic synapses. Although genetic deletion of nArgBP2 in mice leads to manic/bipolar-like behaviors resembling many aspects of symptoms in patients with bipolar disorder, the actual function of nArgBP2 at the synapse is completely unknown. Here, we found that the knockdown (KD) of nArgBP2 by specific small hairpin RNAs (shRNAs) resulted in a dramatic change in dendritic spine morphology. Reintroducing shRNA-resistant nArgBP2 reversed these defects. In particular, nArgBP2 KD impaired spine-synapse formation such that excitatory synapses terminated mostly at dendritic shafts instead of spine heads in spiny neurons, although inhibitory synapse formation was not affected. nArgBP2 KD further caused a marked increase of actin cytoskeleton dynamics in spines, which was associated with increased Wiskott-Aldrich syndrome protein-family verprolin homologous protein 1 (WAVE1)/p21-activated kinase (PAK) phosphorylation and reduced activity of cofilin. These effects of nArgBP2 KD in spines were rescued by inhibiting PAK or activating cofilin combined with sequestration of WAVE. Together, our results suggest that nArgBP2 functions to regulate spine morphogenesis and subsequent spine-synapse formation at glutamatergic synapses. They also raise the possibility that the aberrant regulation of synaptic actin filaments caused by reduced nArgBP2 expression may contribute to the manifestation of the synaptic dysfunction observed in manic/bipolar disorder.
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242
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Namgoong S, Kim NH. Roles of actin binding proteins in mammalian oocyte maturation and beyond. Cell Cycle 2016; 15:1830-43. [PMID: 27152960 DOI: 10.1080/15384101.2016.1181239] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Actin nucleation factors, which promote the formation of new actin filaments, have emerged in the last decade as key regulatory factors controlling asymmetric division in mammalian oocytes. Actin nucleators such as formin-2, spire, and the ARP2/3 complex have been found to be important regulators of actin remodeling during oocyte maturation. Another class of actin-binding proteins including cofilin, tropomyosin, myosin motors, capping proteins, tropomodulin, and Ezrin-Radixin-Moesin proteins are thought to control actin cytoskeleton dynamics at various steps of oocyte maturation. In addition, actin dynamics controlling asymmetric-symmetric transitions after fertilization is a new area of investigation. Taken together, defining the mechanisms by which actin-binding proteins regulate actin cytoskeletons is crucial for understanding the basic biology of mammalian gamete formation and pre-implantation development.
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Affiliation(s)
- Suk Namgoong
- a Department of Animal Sciences , Chungbuk National University , Cheong-Ju , ChungChungBuk-do , Republic of Korea
| | - Nam-Hyung Kim
- a Department of Animal Sciences , Chungbuk National University , Cheong-Ju , ChungChungBuk-do , Republic of Korea
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243
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Yang GN, Kopecki Z, Cowin AJ. Role of Actin Cytoskeleton in the Regulation of Epithelial Cutaneous Stem Cells. Stem Cells Dev 2016; 25:749-59. [PMID: 27021878 DOI: 10.1089/scd.2016.0051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cutaneous stem cells (CSCs) orchestrate the homeostasis and regeneration of mammalian skin. Epithelial CSCs have been isolated and characterized from the skin and hold great potential for tissue engineering and clinical applications. The actin cytoskeleton is known to regulate cell adhesion and motility through its intricate participation in signal transduction and structural modifications. The dynamics of actin cytoskeleton can directly influence CSCs behaviors including tissue morphogenesis, homeostasis, niche maintenance, activation, and wound repair. Various regulators of the actin cytoskeleton including kinases, actin-remodeling proteins, paracrine signals, and micro-RNAs collaborate and contribute to epithelial CSC proliferation, adhesion, and differentiation. This review brings together the latest mechanistic insights into how the actin cytoskeleton participates in the regulation of epithelial CSCs during development, homeostasis, and wound repair.
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Affiliation(s)
- Gink N Yang
- Future Industries Institute, University of South Australia , Adelaide, South Australia, Australia
| | - Zlatko Kopecki
- Future Industries Institute, University of South Australia , Adelaide, South Australia, Australia
| | - Allison J Cowin
- Future Industries Institute, University of South Australia , Adelaide, South Australia, Australia
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244
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The plasma gelsolin levels in atopic dermatitis: Effect of atopy and disease severity. Allergol Immunopathol (Madr) 2016; 44:221-5. [PMID: 26318415 DOI: 10.1016/j.aller.2015.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/24/2015] [Accepted: 05/26/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Gelsolin is an actin-binding protein with several cellular functions including anti-apoptosis and is reported to have an anti-inflammatory effect. Apoptosis of keratinocytes has been implicated as a key mechanism of atopic dermatitis (AD). OBJECTIVE We aimed to determine plasma gelsolin (pGSN) levels in children with atopic dermatitis (AD). METHOD The diagnosis of AD was made according to Hanifin and Rajka criteria. The disease severity was scored by objective SCORAD index by the same allergist. Skin prick testing (SPT), total IgE levels, and eosinophil counts were analyzed. The pGSN levels were determined using ELISA technique. RESULTS Children aged between 0.5 and 3.0 years were included in the study. The children with AD (AD; n=84) were analyzed in two groups according to the presence (AD+/Atopy+; n=54) or absence of SPT positivity (AD+/Atopy-; n=30). The comparisons were made with a healthy control group matched for age and sex (n=81). The median (interquartile range) of pGSN levels in AD+/A+, AD+/A- and control groups were 267μg/ml (236-368), 293 (240-498) and 547 (361-695), respectively (p<0.001). The difference between the control group and AD sub-groups remained significant after Bonferroni correction (p<0.001). Correlation analysis failed to reach significance with the disease severity total IgE levels and eosinophil counts. CONCLUSION This is the first study investigating the association of pGSN levels with AD and disease severity. pGSN levels decreased in AD. These findings suggest that gelsolin may have a role in the disease process in AD patients.
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245
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Colpan M, Moroz NA, Gray KT, Cooper DA, Diaz CA, Kostyukova AS. Tropomyosin-binding properties modulate competition between tropomodulin isoforms. Arch Biochem Biophys 2016; 600:23-32. [PMID: 27091317 DOI: 10.1016/j.abb.2016.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 01/09/2023]
Abstract
The formation and fine-tuning of cytoskeleton in cells are governed by proteins that influence actin filament dynamics. Tropomodulin (Tmod) regulates the length of actin filaments by capping the pointed ends in a tropomyosin (TM)-dependent manner. Tmod1, Tmod2 and Tmod3 are associated with the cytoskeleton of non-muscle cells and their expression has distinct consequences on cell morphology. To understand the molecular basis of differences in the function and localization of Tmod isoforms in a cell, we compared the actin filament-binding abilities of Tmod1, Tmod2 and Tmod3 in the presence of Tpm3.1, a non-muscle TM isoform. Tmod3 displayed preferential binding to actin filaments when competing with other isoforms. Mutating the second or both TM-binding sites of Tmod3 destroyed its preferential binding. Our findings clarify how Tmod1, Tmod2 and Tmod3 compete for binding actin filaments. Different binding mechanisms and strengths of Tmod isoforms for Tpm3.1 contribute to their divergent functional capabilities.
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Affiliation(s)
- Mert Colpan
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
| | - Natalia A Moroz
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Kevin T Gray
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Dillon A Cooper
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Christian A Diaz
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Alla S Kostyukova
- Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
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246
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Egbowon BF, Harris W, Arnott G, Mills CL, Hargreaves AJ. Sub-lethal concentrations of CdCl2 disrupt cell migration and cytoskeletal proteins in cultured mouse TM4 Sertoli cells. Toxicol In Vitro 2016; 32:154-65. [DOI: 10.1016/j.tiv.2015.12.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/29/2015] [Accepted: 12/23/2015] [Indexed: 11/30/2022]
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247
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Addario B, Sandblad L, Persson K, Backman L. Characterisation of Schizosaccharomyces pombe α-actinin. PeerJ 2016; 4:e1858. [PMID: 27069798 PMCID: PMC4824898 DOI: 10.7717/peerj.1858] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 03/08/2016] [Indexed: 11/27/2022] Open
Abstract
The actin cytoskeleton plays a fundamental role in eukaryotic cells. Its reorganization is regulated by a plethora of actin-modulating proteins, such as a-actinin. In higher organisms, α-actinin is characterized by the presence of three distinct structural domains: an N-terminal actin-binding domain and a C-terminal region with EF-hand motif separated by a central rod domain with four spectrin repeats. Sequence analysis has revealed that the central rod domain of α-actinin from the fission yeast Schizosaccharomyces pombe consists of only two spectrin repeats. To obtain a firmer understanding of the structure and function of this unconventional α-actinin, we have cloned and characterized each structural domain. Our results show that this a-actinin isoform is capable of forming dimers and that the rod domain is required for this. However, its actin-binding and cross-linking activity appears less efficient compared to conventional α-actinins. The solved crystal structure of the actin-binding domain indicates that the closed state is stabilised by hydrogen bonds and a salt bridge not present in other α-actinins, which may reduce the affinity for actin.
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Affiliation(s)
- Barbara Addario
- Cell Biology Laboratory, School of Biochemistry and Cell Biology, BioScience Institute, University College Cork , Cork , Ireland
| | - Linda Sandblad
- Department of Molecular Biology, UmeåUniversity , Umeå , Sweden
| | - Karina Persson
- Department of Chemistry, Biological Chemistry , Umeå , Sweden
| | - Lars Backman
- Department of Chemistry, Biological Chemistry , Umeå , Sweden
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248
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Fluvoxamine, an anti-depressant, inhibits human glioblastoma invasion by disrupting actin polymerization. Sci Rep 2016; 6:23372. [PMID: 26988603 PMCID: PMC4796892 DOI: 10.1038/srep23372] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 03/02/2016] [Indexed: 12/31/2022] Open
Abstract
Glioblastoma multiforme (GBM) is the most common malignant brain tumor with a median survival time about one year. Invasion of GBM cells into normal brain is the major cause of poor prognosis and requires dynamic reorganization of the actin cytoskeleton, which includes lamellipodial protrusions, focal adhesions, and stress fibers at the leading edge of GBM. Therefore, we hypothesized that inhibitors of actin polymerization can suppress GBM migration and invasion. First, we adopted a drug repositioning system for screening with a pyrene-actin-based actin polymerization assay and identified fluvoxamine, a clinically used antidepressant. Fluvoxamine, selective serotonin reuptake inhibitor, was a potent inhibitor of actin polymerization and confirmed as drug penetration through the blood-brain barrier (BBB) and accumulation of whole brain including brain tumor with no drug toxicity. Fluvoxamine inhibited serum-induced ruffle formation, cell migration, and invasion of human GBM and glioma stem cells in vitro by suppressing both FAK and Akt/mammalian target of rapamycin signaling. Daily treatment of athymic mice bearing human glioma-initiating cells with fluvoxamine blocked tumor cell invasion and prolonged the survival with almost same dose of anti-depressant effect. In conclusion, fluvoxamine is a promising anti-invasive treatment against GBM with reliable approach.
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249
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Cheng C, Nowak RB, Fowler VM. The lens actin filament cytoskeleton: Diverse structures for complex functions. Exp Eye Res 2016; 156:58-71. [PMID: 26971460 DOI: 10.1016/j.exer.2016.03.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 03/01/2016] [Accepted: 03/07/2016] [Indexed: 01/05/2023]
Abstract
The eye lens is a transparent and avascular organ in the front of the eye that is responsible for focusing light onto the retina in order to transmit a clear image. A monolayer of epithelial cells covers the anterior hemisphere of the lens, and the bulk of the lens is made up of elongated and differentiated fiber cells. Lens fiber cells are very long and thin cells that are supported by sophisticated cytoskeletal networks, including actin filaments at cell junctions and the spectrin-actin network of the membrane skeleton. In this review, we highlight the proteins that regulate diverse actin filament networks in the lens and discuss how these actin cytoskeletal structures assemble and function in epithelial and fiber cells. We then discuss methods that have been used to study actin in the lens and unanswered questions that can be addressed with novel techniques.
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Affiliation(s)
- Catherine Cheng
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Roberta B Nowak
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Velia M Fowler
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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250
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Mittal R, Grati M, Yan D, Liu XZ. Pseudomonas aeruginosa Activates PKC-Alpha to Invade Middle Ear Epithelial Cells. Front Microbiol 2016; 7:255. [PMID: 26973629 PMCID: PMC4777741 DOI: 10.3389/fmicb.2016.00255] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 02/16/2016] [Indexed: 12/31/2022] Open
Abstract
Otitis media (OM) is a group of complex inflammatory disorders affecting the middle ear which can be acute or chronic. Chronic suppurative otitis media (CSOM) is a form of chronic OM characterized by tympanic membrane perforation and discharge. Despite the significant impact of CSOM on human population, it is still an understudied and unexplored research area. CSOM is a leading cause of hearing loss and life-threatening central nervous system complications. Bacterial exposure especially Pseudomonas aeruginosa is the most common cause of CSOM. Our previous studies have demonstrated that P. aeruginosa invades human middle ear epithelial cells (HMEECs). However, molecular mechanisms leading to bacterial invasion of HMEECs are not known. The aim of this study is to characterize the role of PKC pathway in the ability of P. aeruginosa to colonize HMEECs. We observed that otopathogenic P. aeruginosa activates the PKC pathway, specifically phosphorylation of PKC-alpha (PKC-α) in HMEECs. The ability of otopathogenic P. aeruginosa to phosphorylate PKC-α depends on bacterial OprF expression. The activation of PKC-α was associated with actin condensation. Blocking the PKC pathway attenuated the ability of bacteria to invade HMEECs and subsequent actin condensation. This study, for the first time, demonstrates that the host PKC-α pathway is involved in invasion of HMEECs by P. aeruginosa and subsequently to cause OM. Characterizing the role of the host signaling pathway in the pathogenesis of CSOM will provide novel avenues to design effective treatment modalities against the disease.
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Affiliation(s)
- Rahul Mittal
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami Florida, USA
| | - M'hamed Grati
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami Florida, USA
| | - Denise Yan
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami Florida, USA
| | - Xue Z Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, MiamiFlorida, USA; Department of Biochemistry, University of Miami Miller School of Medicine, MiamiFL, USA; Department of Human Genetics, University of Miami Miller School of Medicine, MiamiFL, USA; Department of Otolaryngology, Xiangya Hospital, Central South UniversityChangsha, China
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