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Xue R, Meng H, Yin J, Xia J, Hu Z, Liu H. The Role of Calmodulin vs. Synaptotagmin in Exocytosis. Front Mol Neurosci 2021; 14:691363. [PMID: 34421537 PMCID: PMC8375295 DOI: 10.3389/fnmol.2021.691363] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/19/2021] [Indexed: 12/04/2022] Open
Abstract
Exocytosis is a Ca2+-regulated process that requires the participation of Ca2+ sensors. In the 1980s, two classes of Ca2+-binding proteins were proposed as putative Ca2+ sensors: EF-hand protein calmodulin, and the C2 domain protein synaptotagmin. In the next few decades, numerous studies determined that in the final stage of membrane fusion triggered by a micromolar boost in the level of Ca2+, the low affinity Ca2+-binding protein synaptotagmin, especially synaptotagmin 1 and 2, acts as the primary Ca2+ sensor, whereas calmodulin is unlikely to be functional due to its high Ca2+ affinity. However, in the meantime emerging evidence has revealed that calmodulin is involved in the earlier exocytotic steps prior to fusion, such as vesicle trafficking, docking and priming by acting as a high affinity Ca2+ sensor activated at submicromolar level of Ca2+. Calmodulin directly interacts with multiple regulatory proteins involved in the regulation of exocytosis, including VAMP, myosin V, Munc13, synapsin, GAP43 and Rab3, and switches on key kinases, such as type II Ca2+/calmodulin-dependent protein kinase, to phosphorylate a series of exocytosis regulators, including syntaxin, synapsin, RIM and Ca2+ channels. Moreover, calmodulin interacts with synaptotagmin through either direct binding or indirect phosphorylation. In summary, calmodulin and synaptotagmin are Ca2+ sensors that play complementary roles throughout the process of exocytosis. In this review, we discuss the complementary roles that calmodulin and synaptotagmin play as Ca2+ sensors during exocytosis.
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Affiliation(s)
- Renhao Xue
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity & Infant Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Hao Meng
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Jiaxiang Yin
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
| | - Jingyao Xia
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Zhitao Hu
- Clem Jones Centre for Ageing Dementia Research (CJCADR), Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Huisheng Liu
- Guangzhou Laboratory, Guangzhou, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, China
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2
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Ménasché G, Longé C, Bratti M, Blank U. Cytoskeletal Transport, Reorganization, and Fusion Regulation in Mast Cell-Stimulus Secretion Coupling. Front Cell Dev Biol 2021; 9:652077. [PMID: 33796537 PMCID: PMC8007931 DOI: 10.3389/fcell.2021.652077] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/03/2021] [Indexed: 01/16/2023] Open
Abstract
Mast cells are well known for their role in allergies and many chronic inflammatory diseases. They release upon stimulation, e.g., via the IgE receptor, numerous bioactive compounds from cytoplasmic secretory granules. The regulation of granule secretion and its interaction with the cytoskeleton and transport mechanisms has only recently begun to be understood. These studies have provided new insight into the interaction between the secretory machinery and cytoskeletal elements in the regulation of the degranulation process. They suggest a tight coupling of these two systems, implying a series of specific signaling effectors and adaptor molecules. Here we review recent knowledge describing the signaling events regulating cytoskeletal reorganization and secretory granule transport machinery in conjunction with the membrane fusion machinery that occur during mast cell degranulation. The new insight into MC biology offers novel strategies to treat human allergic and inflammatory diseases targeting the late steps that affect harmful release from granular stores leaving regulatory cytokine secretion intact.
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Affiliation(s)
- Gaël Ménasché
- Laboratory of Molecular Basis of Altered Immune Homeostasis, Imagine Institute, INSERM UMR 1163, Université de Paris, Paris, France
| | - Cyril Longé
- Laboratory of Molecular Basis of Altered Immune Homeostasis, Imagine Institute, INSERM UMR 1163, Université de Paris, Paris, France
| | - Manuela Bratti
- Centre de Recherche sur l'Inflammation, INSERM UMR 1149, CNRS ERL8252, Faculté de Médecine site Bichat, Université de Paris, Paris, France.,Laboratoire d'Excellence Inflamex, Université de Paris, Paris, France
| | - Ulrich Blank
- Centre de Recherche sur l'Inflammation, INSERM UMR 1149, CNRS ERL8252, Faculté de Médecine site Bichat, Université de Paris, Paris, France.,Laboratoire d'Excellence Inflamex, Université de Paris, Paris, France
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3
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Halova I, Rönnberg E, Draberova L, Vliagoftis H, Nilsson GP, Draber P. Changing the threshold-Signals and mechanisms of mast cell priming. Immunol Rev 2019; 282:73-86. [PMID: 29431203 DOI: 10.1111/imr.12625] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mast cells play a key role in allergy and other inflammatory diseases involving engagement of multivalent antigen with IgE bound to high-affinity IgE receptors (FcεRIs). Aggregation of FcεRIs on mast cells initiates a cascade of signaling events that eventually lead to degranulation, secretion of leukotrienes and prostaglandins, and cytokine and chemokine production contributing to the inflammatory response. Exposure to pro-inflammatory cytokines, chemokines, bacterial and viral products, as well as some other biological products and drugs, induces mast cell transition from the basal state into a primed one, which leads to enhanced response to IgE-antigen complexes. Mast cell priming changes the threshold for antigen-mediated activation by various mechanisms, depending on the priming agent used, which alone usually do not induce mast cell degranulation. In this review, we describe the priming processes induced in mast cells by various cytokines (stem cell factor, interleukins-4, -6 and -33), chemokines, other agents acting through G protein-coupled receptors (adenosine, prostaglandin E2 , sphingosine-1-phosphate, and β-2-adrenergic receptor agonists), toll-like receptors, and various drugs affecting the cytoskeleton. We will review the current knowledge about the molecular mechanisms behind priming of mast cells leading to degranulation and cytokine production and discuss the biological effects of mast cell priming induced by several cytokines.
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Affiliation(s)
- Ivana Halova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Elin Rönnberg
- Immunology and Allergy Unit, Department of Medicine, Karolinska Institutet and Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Lubica Draberova
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
| | - Harissios Vliagoftis
- Immunology and Allergy Unit, Department of Medicine, Karolinska Institutet and Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Stockholm, Sweden.,Alberta Respiratory Center and Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Gunnar P Nilsson
- Immunology and Allergy Unit, Department of Medicine, Karolinska Institutet and Clinical Immunology and Transfusion Medicine, Karolinska University Hospital, Stockholm, Sweden.,Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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4
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Knothe Tate ML, Gunning PW, Sansalone V. Emergence of Form from Function - Mechanical Engineering Approaches to Probe the Role of Stem Cell Mechanoadaptation in Sealing Cell Fate. BIOARCHITECTURE 2016; 6:85-103. [PMID: 27739911 DOI: 10.1080/19490992.2016.1229729] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Stem cell "mechanomics" refers to the effect of mechanical cues on stem cell and matrix biology, where cell shape and fate are intrinsic manifestations of form and function. Before specialization, the stem cell itself serves as a sensor and actuator; its structure emerges from its local mechanical milieu as the cell adapts over time. Coupling of novel spatiotemporal imaging and computational methods allows for linking of the energy of adaptation to the structure, biology and mechanical function of the cell. Cutting edge imaging methods enable probing of mechanisms by which stem cells' emergent anisotropic architecture and fate commitment occurs. A novel cell-scale model provides a mechanistic framework to describe stem cell growth and remodeling through mechanical feedback; making use of a generalized virtual power principle, the model accounts for the rate of doing work or the rate of using energy to effect the work. This coupled approach provides a basis to elucidate mechanisms underlying the stem cell's innate capacity to adapt to mechanical stimuli as well as the role of mechanoadaptation in lineage commitment. An understanding of stem cell mechanoadaptation is key to deciphering lineage commitment, during prenatal development, postnatal wound healing, and engineering of tissues.
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Affiliation(s)
- Melissa L Knothe Tate
- a Graduate School of Biomedical Engineering , University of New South Wales , Sydney , Australia
| | - Peter W Gunning
- b School of Medical Sciences, University of New South Wales , Sydney , Australia
| | - Vittorio Sansalone
- c Université Paris-Est Créteil (UPEC), Laboratoire Modélisation et Simulation Multi Echelle , MSME UMR 8208 CNRS, France
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Wang Z, Wann A, Thompson C, Hassen A, Wang W, Knight M. IFT88 influences chondrocyte actin organization and biomechanics. Osteoarthritis Cartilage 2016; 24:544-54. [PMID: 26493329 PMCID: PMC4769095 DOI: 10.1016/j.joca.2015.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/06/2015] [Accepted: 10/12/2015] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Primary cilia are microtubule based organelles which control a variety of signalling pathways important in cartilage development, health and disease. This study examines the role of the intraflagellar transport (IFT) protein, IFT88, in regulating fundamental actin organisation and mechanics in articular chondrocytes. METHODS The study used an established chondrocyte cell line with and without hypomorphic mutation of IFT88 (IFT88(orpk)). Confocal microscopy was used to quantify F-actin and myosin IIB organisation. Viscoelastic cell and actin cortex mechanics were determined using micropipette aspiration with actin dynamics visualised in live cells transfected with LifeACT-GFP. RESULTS IFT88(orpk) cells exhibited a significant increase in acto-myosin stress fibre organisation relative to wild-type (WT) cells in monolayer and an altered response to cytochalasin D. Rounded IFT88(orpk) cells cultured in suspension exhibited reduced cortical actin expression with reduced cellular equilibrium modulus. Micropipette aspiration resulted in reduced membrane bleb formation in IFT88(orpk) cells. Following membrane blebbing, IFT88(orpk) cells exhibited slower reformation of the actin cortex. IFT88(orpk) cells showed increased actin deformability and reduced cortical tension confirming that IFT regulates actin cortex mechanics. The reduced cortical tension is also consistent with the reduced bleb formation. CONCLUSIONS This study demonstrates for the first time that the ciliary protein IFT88 regulates fundamental actin organisation and the stiffness of the actin cortex leading to alterations in cell deformation, mechanical properties and blebbing in an IFT88 chondrocyte cell line. This adds to the growing understanding of the role of primary cilia and IFT in regulating cartilage biology.
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Affiliation(s)
- Z. Wang
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - A.K.T. Wann
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, United Kingdom
| | - C.L. Thompson
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom,Address correspondence and reprint requests to: C.L. Thompson, School of Engineering and Materials Science, Queen Mary University of London, Mile end Rd, London, E1 4NS, United Kingdom. Tel: 44-(0)20-7882-8868.
| | - A. Hassen
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - W. Wang
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - M.M. Knight
- Institute of Bioengineering and School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
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6
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Szabo M, Dulka K, Gulya K. Calmodulin inhibition regulates morphological and functional changes related to the actin cytoskeleton in pure microglial cells. Brain Res Bull 2015; 120:41-57. [PMID: 26551061 DOI: 10.1016/j.brainresbull.2015.11.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/26/2015] [Accepted: 11/03/2015] [Indexed: 01/24/2023]
Abstract
The roles of calmodulin (CaM), a multifunctional intracellular calcium receptor protein, as concerns selected morphological and functional characteristics of pure microglial cells derived from mixed primary cultures from embryonal forebrains of rats, were investigated through use of the CaM antagonists calmidazolium (CALMID) and trifluoperazine (TFP). The intracellular localization of the CaM protein relative to phalloidin, a bicyclic heptapeptide that binds only to filamentous actin, and the ionized calcium-binding adaptor molecule 1 (Iba1), a microglia-specific actin-binding protein, was determined by immunocytochemistry, with quantitative analysis by immunoblotting. In unchallenged and untreated (control) microglia, high concentrations of CaM protein were found mainly perinuclearly in ameboid microglia, while the cell cortex had a smaller CaM content that diminished progressively deeper into the branches in the ramified microglia. The amounts and intracellular distributions of both Iba1 and CaM proteins were altered after lipopolysaccharide (LPS) challenge in activated microglia. CALMID and TFP exerted different, sometimes opposing, effects on many morphological, cytoskeletal and functional characteristics of the microglial cells. They affected the CaM and Iba1 protein expressions and their intracellular localizations differently, inhibited cell proliferation, viability and fluid-phase phagocytosis to different degrees both in unchallenged and in LPS-treated (immunologically challenged) cells, and differentially affected the reorganization of the actin cytoskeleton in the microglial cell cortex, influencing lamellipodia, filopodia and podosome formation. In summary, these CaM antagonists altered different aspects of filamentous actin-based cell morphology and related functions with variable efficacy, which could be important in deciphering the roles of CaM in regulating microglial functions in health and disease.
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Affiliation(s)
- Melinda Szabo
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Karolina Dulka
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary
| | - Karoly Gulya
- Department of Cell Biology and Molecular Medicine, University of Szeged, Szeged, Hungary.
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7
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Choong G, Liu Y, Templeton DM. Interplay of calcium and cadmium in mediating cadmium toxicity. Chem Biol Interact 2014; 211:54-65. [PMID: 24463198 DOI: 10.1016/j.cbi.2014.01.007] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 12/31/2013] [Accepted: 01/13/2014] [Indexed: 01/30/2023]
Abstract
The environmentally important toxic metal, cadmium, exists as the Cd(2+) ion in biological systems, and in this state structurally resembles Ca(2+). Thus, although cadmium exerts a broad range of adverse actions on cells by virtue of its propensity to bind to protein thiol groups, it is now well appreciated that Cd(2+) participates in a number of Ca(2+)-dependent pathways, attributable to its actions as a Ca(2+) mimetic, with a central role for calmodulin, and the Ca(2+)/calmodlin-dependent protein kinase II (CaMK-II) that mediates effects on cytoskeletal dynamics and apoptotic cell death. Cadmium interacts with receptors and ion channels on the cell surface, and with the intracellular estrogen receptor where it binds competitively to residues shared by Ca(2+). It increases cytosolic [Ca(2+)] through several mechanisms, but also decreases transcript levels of some Ca(2+)-transporter genes. It initiates mitochondrial apoptotic pathways, and activates calpains, contributing to mitochondria-independent apoptosis. However, the recent discovery of the role CaMK-II plays in Cd(2+)-induced cell death, and subsequent implication of CaMK-II in Cd(2+)-dependent alterations of cytoskeletal dynamics, has opened a new area of mechanistic cadmium toxicology that is a focus of this review. Calmodulin is necessary for induction of apoptosis by several agents, yet induction of apoptosis by Cd(2+) is prevented by CaMK-II block, and Ca(2+)-dependent phosphorylation of CaMK-II has been linked to increased Cd(2+)-dependent apoptosis. Calmodulin antagonism suppresses Cd(2+)-induced phosphorylation of Erk1/2 and the Akt survival pathway. The involvement of CaMK-II in the effects of Cd(2+) on cell morphology, and particularly the actin cytoskeleton, is profound, favouring actin depolymerization, disrupting focal adhesions, and directing phosphorylated FAK into a cellular membrane. CaMK-II is also implicated in effects of Cd(2+) on microtubules and cadherin junctions. A key question for future cadmium research is whether cytoskeletal disruption leads to apoptosis, or rather if apoptosis initiates cytoskeletal disruption in the context of Cd(2+).
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Affiliation(s)
- Grace Choong
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada
| | - Ying Liu
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada
| | - Douglas M Templeton
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto M5S 1A8, Canada.
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Yang W, Schmid E, Nurbaeva MK, Szteyn K, Leibrock C, Yan J, Schaller M, Gulbins E, Shumilina E, Lang F. Role of acid sphingomyelinase in the regulation of mast cell function. Clin Exp Allergy 2013; 44:79-90. [DOI: 10.1111/cea.12229] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 10/14/2013] [Accepted: 10/23/2013] [Indexed: 12/11/2022]
Affiliation(s)
- W. Yang
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - E. Schmid
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - M. K. Nurbaeva
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - K. Szteyn
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - C. Leibrock
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - J. Yan
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - M. Schaller
- Department of Dermatology; University of Tübingen; Tübingen Germany
| | - E. Gulbins
- Institute of Molecular Biology; University of Duisburg-Essen; Essen Germany
| | - E. Shumilina
- Department of Physiology; University of Tübingen; Tübingen Germany
| | - F. Lang
- Department of Physiology; University of Tübingen; Tübingen Germany
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Ando K, Kudo Y, Aoyagi K, Ishikawa R, Igarashi M, Takahashi M. Calmodulin-dependent regulation of neurotransmitter release differs in subsets of neuronal cells. Brain Res 2013; 1535:1-13. [DOI: 10.1016/j.brainres.2013.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/25/2013] [Accepted: 08/08/2013] [Indexed: 02/05/2023]
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Farrell B, Qian F, Kolomeisky A, Anvari B, Brownell WE. Measuring forces at the leading edge: a force assay for cell motility. Integr Biol (Camb) 2013; 5:204-14. [PMID: 23080534 DOI: 10.1039/c2ib20097j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cancer cells become mobile by remodelling their cytoskeleton to form migratory structures. This transformation is dominated by actin assembly and disassembly (polymerisation and depolymerisation) in the cytoplasm. Synthesis of filamentous actin produces a force at the leading edge that pushes the plasma membrane forward. We describe an assay to measure the restoring force of the membrane in response to forces generated within the cytoplasm adjacent to the membrane. A laser trap is used to form a long membrane nanotube from a living cell and to measure the axial membrane force at the end of the tube. When the tube, resembling a filopodium, is formed and in a relaxed state the axial membrane force exhibits a positive stationary value. This value reflects the influence of the cytoskeleton that acts to pull the tube back to the cell. A dynamic sawtooth force that rides upon the stationary value is also observed. This force is sensitive to a toxin that affects actin assembly and disassembly, but not affected by agents that influence microtubules and myosin light chain kinase. We deduce from the magnitude and characteristics of dynamic force measurements that it originates from depolymerisation and polymerisation of F-actin. The on- and off-rates, the number of working filaments, and the force per filament (2.5 pN) are determined. We suggest the force-dependent transitions are thermodynamically uncoupled as both the on- and off-rates decrease exponentially with a compressive load. We propose kinetic schemes that require attachment of actin filaments to the membrane during depolymerisation. This demonstrates that actin kinetics can be monitored in a living cell by measuring force at the membrane, and used to probe the mobility of cells including cancer cells.
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Affiliation(s)
- Brenda Farrell
- Bobby R Alford Department of Otolaryngology - Head & Neck Surgery, Baylor College of Medicine, Houston, TX 77030, USA.
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Hua SZ. Mapped! A machinery of degranulation in mast cells. Focus on "Serum- and glucocorticoid-inducible kinase SGK1 regulates reorganization of actin cytoskeleton in mast cells upon degranulation". Am J Physiol Cell Physiol 2012; 304:C36-7. [PMID: 23099640 DOI: 10.1152/ajpcell.00330.2012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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12
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Schmid E, Gu S, Yang W, Münzer P, Schaller M, Lang F, Stournaras C, Shumilina E. Serum- and glucocorticoid-inducible kinase SGK1 regulates reorganization of actin cytoskeleton in mast cells upon degranulation. Am J Physiol Cell Physiol 2012; 304:C49-55. [PMID: 23015548 DOI: 10.1152/ajpcell.00179.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aggregation of the high-affinity IgE receptor (FcεRI) on mast cells (MCs) causes MC degranulation, a process that involves cortical F-actin disassembly. Actin depolymerization may be triggered by increase of cytosolic Ca(2+). Entry of Ca(2+) through the Ca(2+) release-activated Ca(2+) (CRAC) channels is under powerful regulation by the serum- and glucocorticoid-inducible kinase SGK1. Moreover, FcεRI-dependent degranulation is decreased in SGK1-deficient (sgk1(-/-)) MCs. The present study addressed whether SGK1 is required for actin cytoskeleton rearrangement in MCs and whether modulation of actin architecture could underlie decreased degranulation of sgk1(-/-) MCs. Confirming previous results, release of β-hexosaminidase reflecting FcεRI-dependent degranulation was impaired in sgk1(-/-) MCs compared with sgk1(+/+) MCs. When CRAC channels were inhibited by 2-aminoethoxydiphenyl borate (2-APB; 50 μM), MC degranulation was strongly decreased in both sgk1(+/+) and sgk1(-/-) MCs and the difference between genotypes was abolished. Moreover, degranulation was impaired by actin-stabilizing (phallacidin) and enhanced by actin-disrupting (cytochalasin B) agents to a similar extent in sgk1(+/+) MCs and sgk1(-/-) MCs, implying a regulatory role of actin reorganization in this event. In line with this, measurements of monomeric (G) and filamentous (F) actin content by FACS analysis and Western blotting of detergent-soluble and -insoluble cell fractions indicated an increase of the G/F-actin ratio in sgk1(+/+) MCs but not in sgk1(-/-) MCs upon FcεRI ligation, an observation reflecting actin depolymerization. In sgk1(+/+) MCs, FcεRI-induced actin depolymerization was abolished by 2-APB. The observed actin reorganization was confirmed by confocal laser microscopic analysis. Our observations uncover SGK1-dependent Ca(2+) entry in mast cells as a novel mechanism regulating actin cytoskeleton.
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Affiliation(s)
- Evi Schmid
- Dept. of Physiology, University of Tübingen, Gmelinstr. 5, D-72072 Tübingen, Germany
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Dráber P, Sulimenko V, Dráberová E. Cytoskeleton in mast cell signaling. Front Immunol 2012; 3:130. [PMID: 22654883 PMCID: PMC3360219 DOI: 10.3389/fimmu.2012.00130] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Accepted: 05/05/2012] [Indexed: 11/13/2022] Open
Abstract
Mast cell activation mediated by the high affinity receptor for IgE (FcεRI) is a key event in allergic response and inflammation. Other receptors on mast cells, as c-Kit for stem cell factor and G protein-coupled receptors (GPCRs) synergistically enhance the FcεRI-mediated release of inflammatory mediators. Activation of various signaling pathways in mast cells results in changes in cell morphology, adhesion to substrate, exocytosis, and migration. Reorganization of cytoskeleton is pivotal in all these processes. Cytoskeletal proteins also play an important role in initial stages of FcεRI and other surface receptors induced triggering. Highly dynamic microtubules formed by αβ-tubulin dimers as well as microfilaments build up from polymerized actin are affected in activated cells by kinases/phosphatases, Rho GTPases and changes in concentration of cytosolic Ca(2+). Also important are nucleation proteins; the γ-tubulin complexes in case of microtubules or Arp 2/3 complex with its nucleation promoting factors and formins in case of microfilaments. The dynamic nature of microtubules and microfilaments in activated cells depends on many associated/regulatory proteins. Changes in rigidity of activated mast cells reflect changes in intermediate filaments build up from vimentin. This review offers a critical appraisal of current knowledge on the role of cytoskeleton in mast cells signaling.
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Affiliation(s)
- Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Vadym Sulimenko
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
| | - Eduarda Dráberová
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics, Academy of Sciences of the Czech RepublicPrague, Czech Republic
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14
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Blank U. The mechanisms of exocytosis in mast cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 716:107-22. [PMID: 21713654 DOI: 10.1007/978-1-4419-9533-9_7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Upon activation through high affinity IgE receptors (FcεRI), mast cells (MCs) can release up to 100% of their content of preformed mediators stored in cytoplasmic secretory granules by compound exocytosis. This causes Type I immediate hypersensitivity reactions and, in the case of inappropriate activation by allergens, the symptoms of allergy. Recent work has uncovered a central role of SNARE (Soluble N-ethylmaleimide-Sensitive Factor (NSF) Attachment Protein (SNAP) Receptors) proteins in regulating the numerous membrane fusion events during exocytosis. This has defined a series of new molecular actors in MC exocytosis that participate in the regulation of membrane fusion and the connection of the fusion machinery with early signaling events. The purpose of this chapter is to describe these proteins and provide a brief overview on their mechanism of action.
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15
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Shimizu T, Owsianik G, Freichel M, Flockerzi V, Nilius B, Vennekens R. TRPM4 regulates migration of mast cells in mice. Cell Calcium 2008; 45:226-32. [PMID: 19046767 DOI: 10.1016/j.ceca.2008.10.005] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 10/18/2008] [Indexed: 11/25/2022]
Abstract
We demonstrate here that the transient receptor potential melastatin subfamily channel, TRPM4, controls migration of bone marrow-derived mast cells (BMMCs), triggered by dinitrophenylated human serum albumin (DNP-HSA) or stem cell factor (SCF). Wild-type BMMCs migrate after stimulation with DNP-HSA or SCF whereas both stimuli do not induce migration in BMMCs derived from TRPM4 knockout mice (trpm4(-/-)). Mast cell migration is a Ca(2+)-dependent process, and TRPM4 likely controls this process by setting the intracellular Ca(2+) level upon cell stimulation. Cell migration depends on filamentous actin (F-actin) rearrangement, since pretreatment with cytochalasin B, an inhibitor of F-actin formation, prevented both DNP-HSA- and SCF-induced migration in wild-type BMMC. Immunocytochemical experiments using fluorescence-conjugated phalloidin demonstrate a reduced level of F-actin formation in DNP-HSA-stimulated BMMCs from trpm4(-/-) mice. Thus, our results suggest that TRPM4 is critically involved in migration of BMMCs by regulation of Ca(2+)-dependent actin cytoskeleton rearrangements.
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Affiliation(s)
- Takahiro Shimizu
- Department of Molecular Cell Biology, Laboratory of Ion Channel Research, KU Leuven, Campus Gasthuisberg, Herestraat 49, bus 802, B-3000 Leuven, Belgium
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16
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Lange K, Gartzke J. F-actin-based Ca signaling-a critical comparison with the current concept of Ca signaling. J Cell Physiol 2006; 209:270-87. [PMID: 16823881 DOI: 10.1002/jcp.20717] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A short comparative survey on the current idea of Ca signaling and the alternative concept of F-actin-based Ca signaling is given. The two hypotheses differ in one central aspect, the mechanism of Ca storage. The current theory rests on the assumption of Ca-accumulating endoplasmic/sarcoplasmic reticulum-derived vesicles equipped with an ATP-dependent Ca pump and IP3- or ryanodine-sensitive channel-receptors for Ca-release. The alternative hypothesis proceeds from the idea of Ca storage at the high-affinity binding sites of actin filaments. Cellular sites of F-actin-based Ca storage are microvilli and the submembrane cytoskeleton. Several specific features of Ca signaling such as store-channel coupling, quantal Ca release, spiking and oscillations, biphasic and "phasic" uptake kinetics, and Ca-induced Ca release (CICR), which are not adequately described by the current concept, are inherent properties of the F-actin system and its dynamic state of treadmilling.
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17
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Hibbert JE, Butt RH, Coorssen JR. Actin is not an essential component in the mechanism of calcium-triggered vesicle fusion. Int J Biochem Cell Biol 2005; 38:461-71. [PMID: 16309945 DOI: 10.1016/j.biocel.2005.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2005] [Accepted: 10/17/2005] [Indexed: 10/25/2022]
Abstract
Actin has been suggested as an essential component in the membrane fusion stage of exocytosis. In some model systems disruption of the actin filament network associated with exocytotic membranes results in a decrease in secretion. Here we analyze the fast Ca2+-triggered membrane fusion steps of regulated exocytosis using a stage-specific preparation of native secretory vesicles (SV) to directly test whether actin plays an essential role in this mechanism. Although present on secretory vesicles, selective pharmacological inhibition of actin did not affect the Ca2+-sensitivity, extent, or kinetics of membrane fusion, nor did the addition of exogenous actin or an anti-actin antibody. There was also no discernable affect on inter-vesicle contact (docking). Overall, the results do not support a direct role for actin in the fast, Ca2+-triggered steps of regulated membrane fusion. It would appear that actin acts elsewhere within the exocytotic cycle.
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Affiliation(s)
- Julie E Hibbert
- Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, Alta., Canada T2N 4N1
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18
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Tao Q, Lloyd B, Lang S, Houston D, Zorn A, Wylie C. A novel G protein-coupled receptor, related to GPR4, is required for assembly of the cortical actin skeleton in early Xenopus embryos. Development 2005; 132:2825-36. [PMID: 15930112 DOI: 10.1242/dev.01866] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
As the fertilized Xenopus egg undergoes sequential cell divisions to form a blastula, each cell develops a network of cortical actin that provides shape and skeletal support for the whole embryo. Disruption of this network causes loss of shape and rigidity of the embryo, and disrupts gastrulation movements. We previously showed that lysophosphatidic acid (LPA) signaling controls the change in cortical actin density that occurs at different stages of the cell cycle. Here, we use a gain-of-function screen, using an egg cDNA expression library, to identify an orphan G protein-coupled cell-surface receptor (XFlop) that controls the overall amount of cortical F-actin. Overexpression of XFlop increases the amount of cortical actin, as well as embryo rigidity and wound healing, whereas depletion of maternal XFlop mRNA does the reverse. Both overexpression and depletion of XFlop perturb gastrulation movements. Reciprocal rescue experiments, and comparison of the effects of their depletion in early embryos, show that the XLPA and XFlop signaling pathways play independent roles in cortical actin assembly, and thus that multiple signaling pathways control the actin skeleton in the blastula.
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Affiliation(s)
- Qinghua Tao
- Division of Developmental Biology, Cincinnati Children's Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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19
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Affiliation(s)
- Martin Oheim
- Laboratory of Neurophysiology and New Microscopies, Ecole Supérieure de Physique et Chimie Industrielles, Paris, France.
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20
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Psatha M, Koffer A, Erent M, Moss SE, Bolsover S. Calmodulin spatial dynamics in RBL-2H3 mast cells. Cell Calcium 2004; 36:51-9. [PMID: 15126056 DOI: 10.1016/j.ceca.2003.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2003] [Revised: 11/15/2003] [Accepted: 11/25/2003] [Indexed: 10/26/2022]
Abstract
A line of rat basophilic leukaemia (RBL) cells, a model of mast cells, stably expressing EGFP-tagged calmodulin secreted normally in response to standard agonists. As reported for other cell types, calmodulin was concentrated in the mitotic spindle poles of dividing cells. In unstimulated interphase cells calmodulin was concentrated in the cell cortex and at a single central location. Disruption of cortical actin eliminated the concentration of calmodulin at the cortex while the central calmodulin concentration was associated with an enrichment of tubulin and is likely to represent the centrosome. Following stimulation with either an agonist that crosslinks Fc receptors or co-application of phorbol ester and a calcium ionophore the interior of the cells lost calmodulin while cortical fluorescence became more pronounced but also less uniform. After stimulation discrete bright puncta of calmodulin-EGFP (CaM-EGFP) appeared in the cell interior. Puncta colocalised with moving lysotracker-labelled granules, suggesting that calmodulin may play a role in organising their transport. Our results show that in interphase RBL cells a large fraction of the calmodulin pool is associated with targets in the actin cytoskeleton and demonstrate the utility of this model system for studying calmodulin biology.
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Affiliation(s)
- Maria Psatha
- Department of Physiology, University College London, London, UK
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21
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Sivalenka RR, Jessberger R. SWAP-70 regulates c-kit-induced mast cell activation, cell-cell adhesion, and migration. Mol Cell Biol 2004; 24:10277-88. [PMID: 15542837 PMCID: PMC529030 DOI: 10.1128/mcb.24.23.10277-10288.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 05/27/2004] [Accepted: 08/24/2004] [Indexed: 12/18/2022] Open
Abstract
SWAP-70, an unusual phosphatidylinositol-3-kinase-dependent protein that interacts with the RhoGTPase Rac, is highly expressed in mast cells. Cultured bone marrow mast cells (BMMC) from SWAP-70(-/-) mice are reduced in FcepsilonRI-triggered degranulation. This report describes the hitherto-unknown role of SWAP-70 in c-kit receptor signaling, a key proliferation and differentiation pathway in mast cells. Consistent with the role of Rac in cell motility and regulation of the actin cytoskeleton, mutant cells show abnormal actin rearrangements and are deficient in migration in vitro and in vivo. SWAP-70(-/-) BMMC are impaired in calcium flux, in proper translocation and activity of Akt kinase (required for mast cell activation and survival), and in translocation of Rac1 and Rac2 upon c-kit stimulation. Adhesion to fibronectin is reduced, but homotypic cell association induced through c-kit is strongly increased in SWAP-70(-/-) BMMC. Homotypic association requires extracellular Ca(2+) and depends on the integrin alpha(L)beta(2) (LFA-1). ERK is hyperactivated upon c-kit signaling in adherent and dispersed mutant cells. Together, we suggest that SWAP-70 is an important regulator of specific effector pathways in c-kit signaling, including mast cell activation, migration, and cell adhesion.
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Affiliation(s)
- Raja Rajeswari Sivalenka
- Mount Sinai School of Medicine, Department of Gene and Cell Medicine, 1425 Madison Ave., Box 1496, New York, NY 10029-6574, USA
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22
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Kettner A, Kumar L, Antón IM, Sasahara Y, de la Fuente M, Pivniouk VI, Falet H, Hartwig JH, Geha RS. WIP regulates signaling via the high affinity receptor for immunoglobulin E in mast cells. ACTA ACUST UNITED AC 2004; 199:357-68. [PMID: 14757742 PMCID: PMC2211794 DOI: 10.1084/jem.20030652] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Wiskott-Aldrich syndrome protein-interacting protein (WIP) stabilizes actin filaments and is important for immunoreceptor-mediated signal transduction leading to actin cytoskeleton rearrangement in T and B cells. Here we report a role for WIP in signaling pathways downstream of the high affinity receptor for immunoglobulin (Ig)E (FcepsilonRI) in mast cells. WIP-deficient bone marrow-derived mast cells (BMMCs) were impaired in their capacity to degranulate and secrete interleukin 6 after FcepsilonRI ligation. Calcium mobilization, phosphorylation of Syk, phospholipase C-g2, and c-Jun NH2-terminal kinase were markedly decreased in WIP-deficient BMMCs. WIP was found to associate with Syk after FcepsilonRI ligation and to inhibit Syk degradation as evidenced by markedly diminished Syk levels in WIP-deficient BMMCs. WIP-deficient BMMCs exhibited no apparent defect in their subcortical actin network and were normal in their ability to form protrusions when exposed to an IgE-coated surface. However, the kinetics of actin changes and the cell shape changes that follow FcepsilonRI signaling were altered in WIP-deficient BMMCs. These results suggest that WIP regulates FcepsilonRI-mediated mast cell activation by regulating Syk levels and actin cytoskeleton rearrangement.
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Affiliation(s)
- Alexander Kettner
- Division of Immunology, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
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23
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Affiliation(s)
- Ulrich Blank
- INSERM E 0225, Bichat Medical School, 16 rue Henri Huchard, BP 416, 75870 Cedex 18, France
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24
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Vitale ML, Carbajal ME. Involvement of myosin II in dopamine-induced reorganization of the lactotroph cell's actin cytoskeleton. J Histochem Cytochem 2004; 52:517-27. [PMID: 15034003 DOI: 10.1177/002215540405200410] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We have shown that dopamine (DA), an inhibitor of prolactin secretion from anterior pituitary lactotrophs, stabilizes the cortical actin cytoskeleton. DA-induced cortical actin stabilization is accompanied by cytoplasmic actin cable disassembly and cell rounding up. Our aim was to identify the mechanisms involved in DA-induced stabilization of the lactotroph's actin cytoskeleton. Here we show that DA increased the association of myosin II with the cell cortex, suggesting that DA facilitates actin-myosin interaction to stabilize cortical actin filaments. This notion was supported by the finding that inhibitors of actin-myosin interaction blocked DA-evoked morphological responses. In addition, our results showed that DA-induced myosin association with the cell periphery may be mediated by inhibition of Rac1/Cdc42-dependent pathways, whereas, DA-induced cytoplasmic actin filament disassembly may be mediated by the inhibition of MLCK- and RhoA-dependent pathways. In conclusion, the present results provide evidence that myosin II is involved in the DA-induced remodeling of actin filaments in lactotrophs, and that DA-induced cortical actin filament assembly and stabilization involve the translocation of myosin II to the cell cortex. This effect requires, among other things, inhibition of the Rac1/Cdc42-dependent signaling pathway.
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Affiliation(s)
- María L Vitale
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.
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25
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Gilchrist M, McCauley SD, Befus AD. Expression, localization, and regulation of NOS in human mast cell lines: effects on leukotriene production. Blood 2004; 104:462-9. [PMID: 15044250 DOI: 10.1182/blood-2003-08-2990] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nitric oxide (NO) is a potent radical produced by nitric oxide synthase (NOS) and has pleiotrophic activities in health and disease. As mast cells (MCs) play a central role in both homeostasis and pathology, we investigated NOS expression and NO production in human MC populations. Endothelial NOS (eNOS) was ubiquitously expressed in both human MC lines and skin-derived MCs, while neuronal NOS (nNOS) was variably expressed in the MC populations studied. The inducible (iNOS) isoform was not detected in human MCs. Both growth factor-independent (HMC-1) and -dependent (LAD 2) MC lines showed predominant nuclear eNOS protein localization, with weaker cytoplasmic expression. nNOS showed exclusive cytoplasmic localization in HMC-1. Activation with Ca(2+) ionophore (A23187) or IgE-anti-IgE induced eNOS phosphorylation and translocation to the nucleus and nuclear and cytoplasmic NO formation. eNOS colocalizes with the leukotriene (LT)-initiating enzyme 5-lipoxygenase (5-LO) in the MC nucleus. The NO donor, S-nitrosoglutathione (SNOG), inhibited, whereas the NOS inhibitor, N(G)-nitro-l-arginine methyl ester (L-NAME), potentiated LT release in a dose-dependent manner. Thus, human MC lines produce NO in both cytoplasmic and nuclear compartments, and endogenously produced NO can regulate LT production by MCs.
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26
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Gilchrist M, Hesslinger C, Befus AD. Tetrahydrobiopterin, a critical factor in the production and role of nitric oxide in mast cells. J Biol Chem 2003; 278:50607-14. [PMID: 14514683 DOI: 10.1074/jbc.m307777200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mast cells (MC) are biologically potent, ubiquitously distributed immune cells with fundamental roles in host integrity and disease. MC diversity and function is regulated by exogenous nitric oxide; however, the production and function of endogenously produced NO in MC is enigmatic. We used rat peritoneal MC (PMC) as an in vivo model to examine intracellular NO production. Live cell confocal analysis of PMC using the NO-sensitive probe diaminofluorescein showed distinct patterns of intracellular NO formation with either antigen (Ag)/IgE (short term) or interferon-gamma (IFN-gamma) (long term). Ag/IgE-induced NO production is preceded by increased intracellular Ca2+, implying constitutive nitric-oxide synthase (NOS) activity. NO formation inhibits MC degranulation. NOS has obligate requirements for tetrahydrobiopterin (BH4), a product of GTP-cyclohydrolase I (CHI), IFN-gamma-stimulated PMC increased CHI mRNA, protein, and enzymatic activity, while decreasing CHI feedback regulatory protein mRNA, causing sustained NO production. Treatment with the CHI inhibitor, 2,4-diamino-6-hydroxypyrimidine, inhibited NO in both IFN-gamma and Ag/IgE systems, increasing MC degranulation. Reconstitution with the exogenous BH4 substrate, sepiapterin, restored NO formation and inhibited exocytosis. Thus, Ag/IgE and IFN-gamma induced intracellular NO plays a key role in MC mediator release, and alterations in NOS activity via BH4 availability may be critical to the heterogeneous responsiveness of MC.
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Affiliation(s)
- Mark Gilchrist
- Glaxo-Heritage Asthma Research Laboratory, Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta T6G 2S2, Canada.
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27
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Koltzscher M, Neumann C, König S, Gerke V. Ca2+-dependent binding and activation of dormant ezrin by dimeric S100P. Mol Biol Cell 2003; 14:2372-84. [PMID: 12808036 PMCID: PMC194886 DOI: 10.1091/mbc.e02-09-0553] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
S100 proteins are EF hand type Ca2+ binding proteins thought to function in stimulus-response coupling by binding to and thereby regulating cellular targets in a Ca2+-dependent manner. To isolate such target(s) of the S100P protein we devised an affinity chromatography approach that selects for S100 protein ligands requiring the biologically active S100 dimer for interaction. Hereby we identify ezrin, a membrane/F-actin cross-linking protein, as a dimer-specific S100P ligand. S100P-ezrin complex formation is Ca2+ dependent and most likely occurs within cells because both proteins colocalize at the plasma membrane after growth factor or Ca2+ ionophore stimulation. The S100P binding site is located in the N-terminal domain of ezrin and is accessible for interaction in dormant ezrin, in which binding sites for F-actin and transmembrane proteins are masked through an association between the N- and C-terminal domains. Interestingly, S100P binding unmasks the F-actin binding site, thereby at least partially activating the ezrin molecule. This identifies S100P as a novel activator of ezrin and indicates that activation of ezrin's cross-linking function can occur directly in response to Ca2+ transients.
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Affiliation(s)
- Max Koltzscher
- Institute for Medical Biochemistry, University of Muenster, Germany
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28
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Pendleton A, Pope B, Weeds A, Koffer A. Latrunculin B or ATP depletion induces cofilin-dependent translocation of actin into nuclei of mast cells. J Biol Chem 2003; 278:14394-400. [PMID: 12566455 DOI: 10.1074/jbc.m206393200] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Increasing cellular G-actin, using latrunculin B, in either intact or permeabilized rat peritoneal mast cells, caused translocation of both actin and an actin regulatory protein, cofilin, into the nuclei. The effect was not associated with an increase in the proportion of apoptotic cells. The major part of the nuclear actin was not stained by rhodamine-phalloidin but could be visualized with an actin antibody, indicating its monomeric or a conformationally distinct state, e.g. cofilin-decorated filaments. Introduction of anti-cofilin into permeabilized cells inhibited nuclear actin accumulation, implying that an active, cofilin-dependent, import exists in this system. Nuclear actin was localized outside the ethidium bromide-stained region, in the extrachromosomal nuclear domain. In permeabilized cells, the appearance of nuclear actin and cofilin was not significantly affected by increasing [Ca(2+)] and/or adding guanosine 5'-O-(3-thiotriphosphate), but was greatly promoted when ATP was withdrawn. Similarly, ATP depletion in intact cells also induced nuclear actin accumulation. In contrast to the effects of latrunculin B, ATP depletion was associated with an increase in cortical F-actin. Our results suggest that the presence of actin in the nucleus may be required for certain stress-induced responses and that cofilin is essential for the nuclear import of actin.
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Affiliation(s)
- Annmarie Pendleton
- Physiology Department, University College London, University Street, United Kingdom
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29
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Neco P, Gil A, Del Mar Francés M, Viniegra S, Gutiérrez LM. The role of myosin in vesicle transport during bovine chromaffin cell secretion. Biochem J 2002; 368:405-13. [PMID: 12225290 PMCID: PMC1223018 DOI: 10.1042/bj20021090] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2002] [Revised: 08/28/2002] [Accepted: 09/12/2002] [Indexed: 11/17/2022]
Abstract
Bovine adrenomedullary cells in culture have been used to study the role of myosin in vesicle transport during exocytosis. Amperometric determination of calcium-dependent catecholamine release from individual digitonin-permeabilized cells treated with 3 microM wortmannin or 20 mM 2,3-butanedione monoxime (BDM) and stimulated by continuous as well as repetitive calcium pulses showed alteration of slow phases of secretion when compared with control untreated cells. The specificity of these drugs for myosin inhibition was further supported by the use of peptide-18, a potent peptide affecting myosin light-chain kinase activity. These results were supported also by studying the impact of these myosin inhibitors on chromaffin granule mobility using direct visualization by dynamic confocal microscopy. Wortmannin and BDM affect drastically vesicle transport throughout the cell cytoplasm, including the region beneath the plasma membrane. Immunocytochemical studies demonstrate the presence of myosin types II and V in the cell periphery. The capability of antibodies to myosin II in abrogating the secretory response from populations of digitonin-permeabilized cells compared with the modest effect caused by anti-myosin V suggests that myosin II plays a fundamental role in the active transport of vesicles occurring in the sub-plasmalemmal area during chromaffin cell secretory activity.
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Affiliation(s)
- Patricia Neco
- Instituto de Neurociencias, Centro Mixto CSIC-Universidad Miguel Hernández, Campus de San Juan, 03550 Alicante, Spain
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30
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Holst J, Sim ATR, Ludowyke RI. Protein phosphatases 1 and 2A transiently associate with myosin during the peak rate of secretion from mast cells. Mol Biol Cell 2002; 13:1083-98. [PMID: 11907284 PMCID: PMC99621 DOI: 10.1091/mbc.01-12-0587] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mast cells undergo cytoskeletal restructuring to allow secretory granules passage through the cortical actomyosin barrier to fuse with the plasma membrane and release inflammatory mediators. Protein phosphorylation is believed to regulate these rearrangements. Although some of the protein kinases implicated in this phosphorylation are known, the relevant protein phosphatases are not. At the peak rate of antigen-induced granule mediator release (2.5 min), protein phosphatases PP1 and PP2A, along with actin and myosin II, are transiently relocated to ruffles on the apical surface and a band at the peripheral edge of the cell. This leaves an area between the nucleus and the peripheral edge significantly depleted (3-5-fold) in these proteins. Phorbol 12-myristate 13-acetate (PMA) plus A23187 induces the same changes, at a time coincident with its slower rate of secretion. Coimmunoprecipitation experiments demonstrated a significantly increased association of myosin with PP1 and PP2A at the time of peak mediator release, with levels of association decreasing by 5 min. Jasplakinolide, an inhibitor of actin assembly, inhibits secretion and the cytoskeletal rearrangements. Surprisingly, jasplakinolide also affects myosin, inducing the formation of short rods throughout the cytoplasm. Inhibition of PP2A inhibited secretion, the cytoskeletal rearrangements, and led to increased phosphorylation of the myosin heavy and light chains at protein kinase C-specific sites. These findings indicate that a dynamic actomyosin cytoskeleton, partially regulated by both PP1 and PP2A, is required for mast cell secretion.
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Affiliation(s)
- Jeff Holst
- Centre for Immunology, St. Vincent's Hospital, University of New South Wales, Sydney, New South Wales, Australia
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31
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Abstract
Rho proteins are well known for their effects on the actin cytoskeleton, and are activated in response to a variety of extracellular stimuli. Several Rho family members are localized to vesicular compartments, and increasing evidence suggests that they play important roles in the trafficking of vesicles on both endocytic and exocytic pathways. In particular, RhoA, RhoB, RhoD, Rac and Cdc42 have been shown to affect various steps of membrane trafficking. The underlying molecular basis for these effects of Rho proteins are incompletely understood, but in the case of Cdc42 it appears that it can drive vesicle movement through Arp2/3 complex-mediated actin polymerization at the surface of the vesicle. This is similar to what is believed to happen when Rac and Cdc42 stimulate actin polymerization at the plasma membrane. Rho proteins may also affect membrane trafficking by altering phosphatidylinositide composition of membrane compartments, or through interactions with microtubules.
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Affiliation(s)
- A J Ridley
- Ludwig Institute for Cancer Research, Royal Free and University College Medical School, 91 Riding House Street, London W1W 7BS, UK.
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32
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Pendleton A, Koffer A. Effects of latrunculin reveal requirements for the actin cytoskeleton during secretion from mast cells. CELL MOTILITY AND THE CYTOSKELETON 2001; 48:37-51. [PMID: 11124709 DOI: 10.1002/1097-0169(200101)48:1<37::aid-cm4>3.0.co;2-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To investigate the role of the actin cytoskeleton in exocytosis, we have tested the effects of latrunculin B, a microfilament-disrupting drug, on secretion from intact and permeabilised rat peritoneal mast cells. The toxin strongly inhibited secretion from intact cells (attached or in suspension) responding to a polybasic agonist, compound 48/80. However, this effect was revealed only after a profound depletion of actin filaments. This was achieved by a long (1 h) exposure of cells to the drug before activation, together with its presence during activation. Maximal inhibition of secretion by such treatment was 85% at 40 microgram/ml latrunculin B. These results indicate that minimal actin structures are essential for the exocytotic response. In contrast, stimulus-induced cell spreading was prevented by latrunculin (5 microgram/ml) applied either before or after activation. The effects of the toxin on intact cells were fully reversible. The responses of permeabilised cells were affected differentially: secretion induced by calcium was more sensitive to latrunculin than that induced by GTP-gamma-S. The calcium response, therefore, is more dependent upon the integrity of the actin cytoskeleton than the response induced by GTP-gamma-S. Again, maximal inhibitory effects (approximately 65 and 25% at 40 microgram/ml) were observed only when cells were exposed to the toxin both before and after permeabilisation. Since the permeabilised cells system focuses on the final steps of exocytosis, the incomplete inhibition suggests that actin plays a modulatory rather than a central role at this stage.
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Affiliation(s)
- A Pendleton
- Physiology Department, University College London, University Street, London, United Kingdom
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