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Qiu Z, Minegishi T, Aoki D, Abe K, Baba K, Inagaki N. Adhesion-clutch between DCC and netrin-1 mediates netrin-1-induced axonal haptotaxis. Front Mol Neurosci 2024; 17:1307755. [PMID: 38375502 PMCID: PMC10875621 DOI: 10.3389/fnmol.2024.1307755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 01/08/2024] [Indexed: 02/21/2024] Open
Abstract
The growth cone, a motile structure located at the tip of growing axons, senses extracellular guidance cues and translates them into directional forces that drive axon outgrowth and guidance. Axon guidance directed by chemical cues on the extracellular adhesive substrate is termed haptotaxis. Recent studies reported that netrin-1 on the substrate functions as a haptotactic axon guidance cue. However, the mechanism mediating netrin-1-induced axonal haptotaxis remains unclear. Here, we demonstrate that substrate-bound netrin-1 induces axonal haptotaxis by facilitating physical interactions between the netrin-1 receptor, DCC, and the adhesive substrates. DCC serves as an adhesion receptor for netrin-1. The clutch-linker molecule shootin1a interacted with DCC, linking it to actin filament retrograde flow at the growth cone. Speckle imaging analyses showed that DCC underwent either grip (stop) or retrograde slip on the adhesive substrate. The grip state was more prevalent on netrin-1-coated substrate compared to the control substrate polylysine, thereby transmitting larger traction force on the netrin-1-coated substrate. Furthermore, disruption of the linkage between actin filament retrograde flow and DCC by shootin1 knockout impaired netrin-1-induced axonal haptotaxis. These results suggest that the directional force for netrin-1-induced haptotaxis is exerted on the substrates through the adhesion-clutch between DCC and netrin-1 which occurs asymmetrically within the growth cone.
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Affiliation(s)
| | | | | | | | | | - Naoyuki Inagaki
- Laboratory of Systems Neurobiology and Medicine, Division of Biological Science, Nara Institute of Science and Technology, Nara, Japan
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2
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Schacke S, Kirkpatrick J, Stocksdale A, Bauer R, Hagel C, Riecken LB, Morrison H. Ezrin deficiency triggers glial fibrillary acidic protein upregulation and a distinct reactive astrocyte phenotype. Glia 2022; 70:2309-2329. [PMID: 35929192 DOI: 10.1002/glia.24253] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 07/12/2022] [Accepted: 07/15/2022] [Indexed: 01/02/2023]
Abstract
Astrocytes are increasingly being recognized as contributors to physiological brain function and behavior. Astrocytes engage in glia-synaptic interactions through peripheral astrocyte processes, thus modulating synaptic signaling, for example, by handling glutamate removal from the synaptic cleft and (re)provision to axonal terminals. Peripheral astrocyte processes are ultrafine membrane protrusions rich in the membrane-to-actin cytoskeleton linker Ezrin, an essential component of in vitro filopodia formation and in vivo peripheral astrocyte process motility. Consequently, it has been postulated that Ezrin significantly contributes to neurodevelopment as well as astrocyte functions within the adult brain. However, while Ezrin has been studied in vitro within cultured primary astrocytes, in vivo studies on the role of Ezrin in astrocytes remain to be conducted and consequences of its depletion to be studied. Here, we investigated consequences of Ezrin deletion in the mouse brain starting from early neuronal specification. While Ezrin knockout did not impact prenatal cerebral cortex development, behavioral phenotyping depicted reduced exploratory behavior. Starting with postnatal appearance of glia cells, Ezrin was verified to remain predominantly expressed in astrocytes. Proteome analysis of Ezrin deficient astrocytes revealed alterations in glutamate and ion homeostasis, metabolism and cell morphology - important processes for synaptic signal transmission. Notably, Ezrin deletion in astrocytes provoked (GFAP) glial fibrillary acidic protein upregulation - a marker of astrocyte activation and reactive astrogliosis. However, this spontaneous, reactive astrogliosis exhibited proteome changes distinct from ischemic-induced reactive astrogliosis. Moreover, in experimental ischemic stroke, Ezrin knockout mice displayed reduced infarct volume, indicating a protective effect of the Ezrin deletion-induced changes and astrogliosis.
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Affiliation(s)
- Stephan Schacke
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | | | - Amy Stocksdale
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Reinhard Bauer
- Institute of Molecular Cell Biology, CMB, Jena University Hospital, Jena, Germany
| | - Christian Hagel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Helen Morrison
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany.,Faculty of Biological Sciences, Friedrich-Schiller University, Jena, Germany
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Vacano GN, Gibson DS, Turjoman AA, Gawryluk JW, Geiger JD, Duncan M, Patterson D. Proteomic analysis of six- and twelve-month hippocampus and cerebellum in a murine Down syndrome model. Neurobiol Aging 2017; 63:96-109. [PMID: 29245059 DOI: 10.1016/j.neurobiolaging.2017.11.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/09/2017] [Accepted: 11/17/2017] [Indexed: 02/07/2023]
Abstract
This study was designed to investigate the brain proteome of the Ts65Dn mouse model of Down syndrome. We profiled the cerebellum and hippocampus proteomes of 6- and 12-month-old trisomic and disomic mice by difference gel electrophoresis. We quantified levels of 2082 protein spots and identified 272 (170 unique UniProt accessions) by mass spectrometry. Four identified proteins are encoded by genes trisomic in the Ts65Dn mouse. Three of these (CRYZL11, EZR, and SOD1) were elevated with p-value <0.05, and 2 proteins encoded by disomic genes (MAPRE3 and PHB) were reduced. Intergel comparisons based on age (6 vs. 12 months) and brain region (cerebellum vs. hippocampus) revealed numerous differences. Specifically, 132 identified proteins were different between age groups, and 141 identified proteins were different between the 2 brain regions. Our results suggest that compensatory mechanisms exist, which ameliorate the effect of trisomy in the Ts65Dn mice. Differences observed during aging may play a role in the accelerated deterioration of learning and memory seen in Ts65Dn mice.
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Affiliation(s)
- Guido N Vacano
- Knoebel Institute for Healthy Aging, Eleanor Roosevelt Institute, and Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - David S Gibson
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Abdullah Arif Turjoman
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Jeremy W Gawryluk
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - Jonathan D Geiger
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, USA
| | - Mark Duncan
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - David Patterson
- Knoebel Institute for Healthy Aging, Eleanor Roosevelt Institute, and Department of Biological Sciences, University of Denver, Denver, CO, USA.
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4
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Inhibition of N1-Src kinase by a specific SH3 peptide ligand reveals a role for N1-Src in neurite elongation by L1-CAM. Sci Rep 2017; 7:43106. [PMID: 28220894 PMCID: PMC5318895 DOI: 10.1038/srep43106] [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] [Received: 09/05/2016] [Accepted: 01/19/2017] [Indexed: 11/09/2022] Open
Abstract
In the mammalian brain the ubiquitous tyrosine kinase, C-Src, undergoes splicing to insert short sequences in the SH3 domain to yield N1- and N2-Src. We and others have previously shown that the N-Srcs have altered substrate specificity and kinase activity compared to C-Src. However, the exact functions of the N-Srcs are unknown and it is likely that N-Src signalling events have been misattributed to C-Src because they cannot be distinguished by conventional Src inhibitors that target the kinase domain. By screening a peptide phage display library, we discovered a novel ligand (PDN1) that targets the unique SH3 domain of N1-Src and inhibits N1-Src in cells. In cultured neurons, PDN1 fused to a fluorescent protein inhibited neurite outgrowth, an effect that was mimicked by shRNA targeting the N1-Src microexon. PDN1 also inhibited L1-CAM-dependent neurite elongation in cerebellar granule neurons, a pathway previously shown to be disrupted in Src−/− mice. PDN1 therefore represents a novel tool for distinguishing the functions of N1-Src and C-Src in neurons and is a starting point for the development of a small molecule inhibitor of N1-Src.
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5
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Buck KB, Schaefer AW, Schoonderwoert VT, Creamer MS, Dufresne ER, Forscher P. Local Arp2/3-dependent actin assembly modulates applied traction force during apCAM adhesion site maturation. Mol Biol Cell 2016; 28:98-110. [PMID: 27852899 PMCID: PMC5221634 DOI: 10.1091/mbc.e16-04-0228] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 01/06/2023] Open
Abstract
In growth cones, local Arp 2/3-dependent actin assembly mechanically buffers apCAM adhesions from retrograde flow–associated traction forces. The resulting propulsive forces drive the exploratory motility of inductopodia. Increasing the stiffness of apCAM targets induces an extensive 3D actin cup to form at the adhesion during evoked growth responses. Homophilic binding of immunoglobulin superfamily molecules such as the Aplysia cell adhesion molecule (apCAM) leads to actin filament assembly near nascent adhesion sites. Such actin assembly can generate significant localized forces that have not been characterized in the larger context of axon growth and guidance. We used apCAM-coated bead substrates applied to the surface of neuronal growth cones to characterize the development of forces evoked by varying stiffness of mechanical restraint. Unrestrained bead propulsion matched or exceeded rates of retrograde network flow and was dependent on Arp2/3 complex activity. Analysis of growth cone forces applied to beads at low stiffness of restraint revealed switching between two states: frictional coupling to retrograde flow and Arp2/3-dependent propulsion. Stiff mechanical restraint led to formation of an extensive actin cup matching the geometric profile of the bead target and forward growth cone translocation; pharmacological inhibition of the Arp2/3 complex or Rac attenuated F-actin assembly near bead binding sites, decreased the efficacy of growth responses, and blocked accumulation of signaling molecules associated with nascent adhesions. These studies introduce a new model for regulation of traction force in which local actin assembly forces buffer nascent adhesion sites from the mechanical effects of retrograde flow.
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Affiliation(s)
- Kenneth B Buck
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Andrew W Schaefer
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Vincent T Schoonderwoert
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
| | - Matthew S Creamer
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520
| | - Eric R Dufresne
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520
| | - Paul Forscher
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520
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6
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Samatov TR, Wicklein D, Tonevitsky AG. L1CAM: Cell adhesion and more. ACTA ACUST UNITED AC 2016; 51:25-32. [DOI: 10.1016/j.proghi.2016.05.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 05/20/2016] [Indexed: 12/17/2022]
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Cell Adhesion Molecules and Ubiquitination-Functions and Significance. BIOLOGY 2015; 5:biology5010001. [PMID: 26703751 PMCID: PMC4810158 DOI: 10.3390/biology5010001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/02/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system.
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Siegenthaler D, Enneking EM, Moreno E, Pielage J. L1CAM/Neuroglian controls the axon-axon interactions establishing layered and lobular mushroom body architecture. ACTA ACUST UNITED AC 2015; 208:1003-18. [PMID: 25825519 PMCID: PMC4384726 DOI: 10.1083/jcb.201407131] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The establishment of neuronal circuits depends on the guidance of axons both along and in between axonal populations of different identity; however, the molecular principles controlling axon-axon interactions in vivo remain largely elusive. We demonstrate that the Drosophila melanogaster L1CAM homologue Neuroglian mediates adhesion between functionally distinct mushroom body axon populations to enforce and control appropriate projections into distinct axonal layers and lobes essential for olfactory learning and memory. We addressed the regulatory mechanisms controlling homophilic Neuroglian-mediated cell adhesion by analyzing targeted mutations of extra- and intracellular Neuroglian domains in combination with cell type-specific rescue assays in vivo. We demonstrate independent and cooperative domain requirements: intercalating growth depends on homophilic adhesion mediated by extracellular Ig domains. For functional cluster formation, intracellular Ankyrin2 association is sufficient on one side of the trans-axonal complex whereas Moesin association is likely required simultaneously in both interacting axonal populations. Together, our results provide novel mechanistic insights into cell adhesion molecule-mediated axon-axon interactions that enable precise assembly of complex neuronal circuits.
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Affiliation(s)
- Dominique Siegenthaler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland University of Basel, 4003 Basel, Switzerland
| | - Eva-Maria Enneking
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland University of Basel, 4003 Basel, Switzerland
| | - Eliza Moreno
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Jan Pielage
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
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9
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Gomez TM, Letourneau PC. Actin dynamics in growth cone motility and navigation. J Neurochem 2013; 129:221-34. [PMID: 24164353 DOI: 10.1111/jnc.12506] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 10/07/2013] [Accepted: 10/16/2013] [Indexed: 12/17/2022]
Abstract
Motile growth cones lead growing axons through developing tissues to synaptic targets. These behaviors depend on the organization and dynamics of actin filaments that fill the growth cone leading margin [peripheral (P-) domain]. Actin filament organization in growth cones is regulated by actin-binding proteins that control all aspects of filament assembly, turnover, interactions with other filaments and cytoplasmic components, and participation in producing mechanical forces. Actin filament polymerization drives protrusion of sensory filopodia and lamellipodia, and actin filament connections to the plasma membrane link the filament network to adhesive contacts of filopodia and lamellipodia with other surfaces. These contacts stabilize protrusions and transduce mechanical forces generated by actomyosin activity into traction that pulls an elongating axon along the path toward its target. Adhesive ligands and extrinsic guidance cues bind growth cone receptors and trigger signaling activities involving Rho GTPases, kinases, phosphatases, cyclic nucleotides, and [Ca++] fluxes. These signals regulate actin-binding proteins to locally modulate actin polymerization, interactions, and force transduction to steer the growth cone leading margin toward the sources of attractive cues and away from repellent guidance cues.
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Affiliation(s)
- Timothy M Gomez
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA
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10
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Viswanatha R, Wayt J, Ohouo PY, Smolka MB, Bretscher A. Interactome analysis reveals ezrin can adopt multiple conformational states. J Biol Chem 2013; 288:35437-51. [PMID: 24151071 DOI: 10.1074/jbc.m113.505669] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ezrin, a member of the ezrin-radixin-moesin family (ERM), is an essential regulator of the structure of microvilli on the apical aspect of epithelial cells. Ezrin provides a linkage between membrane-associated proteins and F-actin, oscillating between active/open and inactive/closed states, and is regulated in part by phosphorylation of a C-terminal threonine. In the open state, ezrin can bind a number of ligands, but in the closed state the ligand-binding sites are inaccessible. In vitro analysis has proposed that there may be a third hyperactivated form of ezrin. To gain a better understanding of ezrin, we conducted an unbiased proteomic analysis of ezrin-binding proteins in an epithelial cell line, Jeg-3. We refined our list of interactors by comparing the interactomes using quantitative mass spectrometry between wild-type ezrin, closed ezrin, open ezrin, and hyperactivated ezrin. The analysis reveals several novel interactors confirmed by their localization to microvilli, as well as a significant class of proteins that bind closed ezrin. Taken together, the data indicate that ezrin can exist in three different conformational states, and different ligands "perceive" ezrin conformational states differently.
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Affiliation(s)
- Raghuvir Viswanatha
- From the Department of Molecular Biology and Genetics and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853
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11
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Aikawa Y. Ubiquitination within the membrane-proximal ezrin-radixin-moesin (ERM)-binding region of the L1 cell adhesion molecule. Commun Integr Biol 2013; 6:e24750. [PMID: 23986810 PMCID: PMC3737756 DOI: 10.4161/cib.24750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 04/19/2013] [Accepted: 04/19/2013] [Indexed: 12/14/2022] Open
Abstract
The dynamic turnover of the L1 cell adhesion molecule to and from the plasma membrane that is mediated through exo-and endocytic trafficking is central to axon outgrowth. Although the ubiquitination of L1 in response to incubation with an L1 antibody that mimics L1-L1 homophilic binding has been previously shown, the endocytic trafficking pathway of the ubiquitinated L1 destined for degradation is yet unclear. I have recently shown that the ubiquitinated L1 is endocytosed by Rabex-5, which is an ubiquitin-binding protein and guanine nucleotide exchange factor for Rab5, into early endosomes from the plasma membrane. Here, I speculate on the putative ubiquitination site within the membrane-proximal ezrin-binding motif in the cytoplasmic domain of L1 and discuss the regulatory role of this motif in the competition between ubiquitination and the binding of ezrin prior to L1 internalization.
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Affiliation(s)
- Yoshikatsu Aikawa
- Laboratory of Neural Membrane Biology; Graduate School of Brain Science; Doshisha University; Kyoto, Japan
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12
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Harris HJ, Clerte C, Farquhar MJ, Goodall M, Hu K, Rassam P, Dosset P, Wilson GK, Balfe P, IJzendoorn SC, Milhiet PE, McKeating JA. Hepatoma polarization limits CD81 and hepatitis C virus dynamics. Cell Microbiol 2013; 15:430-45. [PMID: 23126643 PMCID: PMC3599488 DOI: 10.1111/cmi.12047] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 09/08/2012] [Accepted: 09/27/2012] [Indexed: 12/12/2022]
Abstract
Many viruses target the polarized epithelial apex during host invasion. In contrast, hepatitis C virus (HCV) engages receptors at the basal surface of hepatocytes in the polarized liver parenchyma. Hepatocyte polarization limits HCV entry by undefined mechanism(s). Given the recent reports highlighting a role for receptor mobility in pathogen entry, we studied the effect(s) of hepatocyte polarization on viral receptor and HCV pseudoparticle (HCVpp) dynamics using real-time fluorescence recovery after photobleaching and single particle tracking. Hepatoma polarization reduced CD81 and HCVpp dynamics at the basal membrane. Since cell polarization is accompanied by changes in the actin cytoskeleton and CD81 links to actin via its C-terminus, we studied the dynamics of a mutant CD81 lacking a C-terminal tail (CD81(ΔC)) and its effect(s) on HCVpp mobility and infection. CD81(ΔC) showed an increased frequency of confined trajectories and a reduction of Brownian diffusing molecules compared to wild-type protein in non-polarized cells. However, these changes were notobserved in polarized cells. HCVpp showed a significant reduction in Brownian diffusion and infection of CD81(ΔC) expressing non-polarized cells. In summary, these data highlight the dynamic nature of CD81 and demonstrate a role for CD81 lateral diffusion to regulate HCV infection in a polarization-dependent manner.
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Affiliation(s)
- H J Harris
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - C Clerte
- Unité 1054, InsermMontpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048Montpellier, France
| | - M J Farquhar
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - M Goodall
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - K Hu
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - P Rassam
- Unité 1054, InsermMontpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048Montpellier, France
| | - P Dosset
- Unité 1054, InsermMontpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048Montpellier, France
| | - G K Wilson
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - P Balfe
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
| | - S C IJzendoorn
- Department of Cell Biology, University Medical Center Groningen, University of GroningenGroningen, The Netherlands
| | - P E Milhiet
- Unité 1054, InsermMontpellier, France
- Centre de Biochimie Structurale, Université de Montpellier, CNRS, UMR 5048Montpellier, France
| | - J A McKeating
- School of Immunity and Infection, University of BirminghamBirmingham, UK
- NIHR Centre for Liver Disease, University of BirminghamBirmingham, UK
- NIHR Liver Biomedical Research Unit, University of BirminghamBirmingham, UK
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13
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Aikawa Y. Rabex-5 protein regulates the endocytic trafficking pathway of ubiquitinated neural cell adhesion molecule L1. J Biol Chem 2012; 287:32312-23. [PMID: 22846990 DOI: 10.1074/jbc.m112.374322] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ubiquitination of integral membrane proteins is a common posttranslational modification used to mediate endocytosis and endocytic sorting of cell surface proteins in eukaryotic cells. Ubiquitin (Ub)-binding proteins (UBPs) regulate the stability, function, and localization of ubiquitinated cell surface proteins in the endocytic pathway. Here, I report that the immunoglobulin superfamily cell adhesion molecule L1 undergoes ubiquitination and dephosphorylation on the plasma membrane upon L1 antibody-induced clustering, which mimics L1-L1 homophilic binding, and that these modifications are critical for obtaining the maximal rate of internalization and trafficking to the lysosome, but not to the proteasome. Notably, L1 antibody-induced clustering leads to the association of ubiquitinated L1 with Rabex-5, a UBP and guanine nucleotide exchange factor for Rab5, via interaction with the motif interacting with Ub (MIU) domain, but not the A20-type zinc finger domain. This interaction specifically depends on the presence of an Ub moiety on lysine residues in L1. Rabex-5 expression accelerates the internalization rates of L1(WT) and L1(Y1176A), a tyrosine-based motif mutant, but not L1(K11R), an ubiquitination-deficient mutant, leading to the accumulation of ubiquitinated L1 on endosomes. In contrast, RNA interference-mediated knockdown of Rabex-5 impairs the internalizations of L1(WT) and L1(Y1176A), but not L1(K11R) from the plasma membrane. Overall, these results provide a novel mechanistic insight into how Rabex-5 regulates internalization and postendocytic trafficking of ubiquitinated L1 destined for lysosomal degradation.
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Affiliation(s)
- Yoshikatsu Aikawa
- Laboratory of Neural Membrane Biology, Graduate School of Brain Science, Doshisha University, 1-3 Miyakodani, Kyotanabe, Kyoto 610-0394, Japan.
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14
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Epple LM, Griffiths SG, Dechkovskaia AM, Dusto NL, White J, Ouellette RJ, Anchordoquy TJ, Bemis LT, Graner MW. Medulloblastoma exosome proteomics yield functional roles for extracellular vesicles. PLoS One 2012; 7:e42064. [PMID: 22848702 PMCID: PMC3407172 DOI: 10.1371/journal.pone.0042064] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 07/02/2012] [Indexed: 12/21/2022] Open
Abstract
Medulloblastomas are the most prevalent malignant pediatric brain tumors. Survival for these patients has remained largely the same for approximately 20 years, and our therapies for these cancers cause significant health, cognitive, behavioral and developmental sequelae for those who survive the tumor and their treatments. We obviously need a better understanding of the biology of these tumors, particularly with regard to their migratory/invasive behaviors, their proliferative propensity, and their abilities to deflect immune responses. Exosomes, virus-sized membrane vesicles released extracellularly from cells after formation in, and transit thru, the endosomal pathway, may play roles in medulloblastoma pathogenesis but are as yet unstudied in this disease. Here we characterized exosomes from a medulloblastoma cell line with biochemical and proteomic analyses, and included characterization of patient serum exosomes. Further scrutiny of the proteomic data suggested functional properties of the exosomes that are relevant to medulloblastoma tumor biology, including their roles as proliferation stimulants, their activities as attractants for tumor cell migration, and their immune modulatory impacts on lymphocytes. Aspects of this held true for exosomes from other medulloblastoma cell lines as well. Additionally, pathway analyses suggested a possible role for the transcription factor hepatocyte nuclear factor 4 alpha (HNF4A); however, inhibition of the protein’s activity actually increased D283MED cell proliferation/clonogenecity, suggesting that HNF4A may act as a tumor suppressor in this cell line. Our work demonstrates that relevant functional properties of exosomes may be derived from appropriate proteomic analyses, which translate into mechanisms of tumor pathophysiology harbored in these extracellular vesicles.
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Affiliation(s)
- Laura M. Epple
- Department of Neurosurgery, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
- Cell and Molecular Biology Program, Cancer Biology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | | | - Anjelika M. Dechkovskaia
- Department of Surgery, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Nathaniel L. Dusto
- Department of Neurosurgery, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Jason White
- Department of Neurosurgery, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
| | | | - Thomas J. Anchordoquy
- School of Pharmacy, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Lynne T. Bemis
- Department of Medical Oncology, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
| | - Michael W. Graner
- Department of Neurosurgery, Anschutz Medical Center, University of Colorado Denver, Aurora, Colorado, United States of America
- * E-mail:
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15
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Role of L1CAM for axon sprouting and branching. Cell Tissue Res 2012; 349:39-48. [DOI: 10.1007/s00441-012-1345-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 01/25/2012] [Indexed: 01/02/2023]
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16
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Activation of ezrin/radixin/moesin mediates attractive growth cone guidance through regulation of growth cone actin and adhesion receptors. J Neurosci 2012; 32:282-96. [PMID: 22219290 DOI: 10.1523/jneurosci.4794-11.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The development of a functioning neural network relies on responses of axonal growth cones to molecular guidance cues that are encountered en route to their target tissue. Nerve growth factor (NGF) and neurotrophin-3 serve as attractive cues for chick embryo sensory growth cones in vitro and in vivo, but little is known about the actin-binding proteins necessary to mediate this response. The evolutionarily conserved ezrin/radixin/moesin (ERM) family of proteins can tether actin filaments to the cell membrane when phosphorylated at a conserved threonine residue. Here we show that acute neurotrophin stimulation rapidly increases active phospho-ERM levels in chick sensory neuron growth cone filopodia, coincident with an increase in filopodial L1 and β-integrin. Disrupting ERM function with a dominant-negative construct (DN-ERM) results in smaller and less motile growth cones with disorganized actin filaments. Previously, we found that NGF treatment increases actin-depolymerizing factor (ADF)/cofilin activity and growth cone F-actin (Marsick et al., 2010). Here, we show this F-actin increase, as well as attractive turning to NGF, is blocked when ERM function is disrupted despite normal activation of ADF/cofilin. We further show that DN-ERM expression disrupts leading edge localization of active ADF/cofilin and free F-actin barbed ends. Moreover, filopodial phospho-ERM levels are increased by incorporation of active ADF/cofilin and reduced by knockdown of L1CAM.Together, these data suggest that ERM proteins organize actin filaments in sensory neuron growth cones and are crucial for neurotrophin-induced remodeling of F-actin and redistribution of adhesion receptors.
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17
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Sakurai T. The role of NrCAM in neural development and disorders--beyond a simple glue in the brain. Mol Cell Neurosci 2011; 49:351-63. [PMID: 22182708 DOI: 10.1016/j.mcn.2011.12.002] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 11/03/2011] [Accepted: 12/02/2011] [Indexed: 12/15/2022] Open
Abstract
NrCAM is a neuronal cell adhesion molecule of the L1 family of immunoglobulin super family. It plays a wide variety of roles in neural development, including cell proliferation and differentiation, axon growth and guidance, synapse formation, and the formation of the myelinated nerve structure. NrCAM functions in cell adhesion and modulates signaling pathways in neural development through multiple molecular interactions with guidance and other factors. Alterations in NrCAM structure/expression are associated with psychiatric disorders such as autism and drug addiction and with tumor progression. The mechanisms of NrCAM participation in development and how these might be perturbed in disorders are reviewed.
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Affiliation(s)
- Takeshi Sakurai
- Medical Innovation Center, Kyoto University Graduate School of Medicine, Japan.
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18
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Itofusa R, Kamiguchi H. Polarizing membrane dynamics and adhesion for growth cone navigation. Mol Cell Neurosci 2011; 48:332-8. [PMID: 21459144 DOI: 10.1016/j.mcn.2011.03.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 03/23/2011] [Accepted: 03/24/2011] [Indexed: 10/18/2022] Open
Abstract
Neuronal network formation relies on the motile behavior of growth cones at the tip of navigating axons. Accumulating evidence indicates that growth cone motility requires spatially controlled endocytosis and exocytosis that can redistribute bulk membrane and functional cargos such as cell adhesion molecules. For axon elongation, the growth cone recycles cell adhesion molecules from its rear to its leading front through endosomes, thereby polarizing growth cone adhesiveness along the axis of migration direction. In response to extracellular guidance cues, the growth cone turns by retrieving membrane components from the retractive side or by supplying them to the side facing the new direction. We propose that polarized membrane trafficking creates adhesion gradients along and across the front-to-rear axis of growth cones that are essential for axon elongation and turning, respectively. This review will examine how growth cone adhesiveness can be patterned by spatially coordinated endocytosis and exocytosis of cell adhesion molecules. This article is part of a Special Issue entitled 'Neuronal Function'.
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Affiliation(s)
- Rurika Itofusa
- Laboratory for Neuronal Growth Mechanisms, RIKEN Brain Science Institute, 2–1 Hirosawa, Wako, Saitama 351–0198, Japan
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19
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Cavallaro U, Dejana E. Adhesion molecule signalling: not always a sticky business. Nat Rev Mol Cell Biol 2011; 12:189-97. [PMID: 21346732 DOI: 10.1038/nrm3068] [Citation(s) in RCA: 197] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The signalling activity of cell adhesion molecules (CAMs) such as cadherins, immunoglobulin-like CAMs or integrins has long been considered to be a direct consequence of their adhesive properties. However, there are physiological and pathological processes that reduce or even abrogate the adhesive properties of CAMs, such as cleavage, conformational changes, mutations and shedding. In some cases these 'adhesion deficient' CAMs still retain signalling properties through their cytoplasmic domains and/or their mutated or truncated extracellular domains. The ability of CAMs to activate signal transduction cascades in the absence of cell adhesion significantly extends their range of biological activities.
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Affiliation(s)
- Ugo Cavallaro
- Cell Adhesion and Signalling, FIRC Institute of Molecular Oncology (IFOM), Via Adamello 16, 20139 Milan, Italy.
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20
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Gibson NJ. Cell adhesion molecules in context: CAM function depends on the neighborhood. Cell Adh Migr 2011; 5:48-51. [PMID: 20948304 PMCID: PMC3038097 DOI: 10.4161/cam.5.1.13639] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 09/16/2010] [Indexed: 01/03/2023] Open
Abstract
Cell adhesion molecules (CAMs) are now known to mediate much more than adhesion between cells and between cells and the extracellular matrix. Work by many researchers has illuminated their roles in modulating activation of molecules such as receptor tyrosine kinases, with subsequent effects on cell survival, migration, and process extension. CAMs also are known to serve as substrates for proteases which can create diffusible fragments capable of signaling independently from the CAM. The diversity of interactions is further modulated by membrane rafts, which can co-localize or separate potential signaling partners to affect the likelihood of a given signaling pathway being activated. Given the ever-growing number of known CAMs and the fact that their heterophilic binding in cis or in trans can affect their interactions with other molecules, including membrane-bound receptors, one would predict a wide range of effects attributable to a particular CAM in a particular cell at a particular stage of development. The function(s) of a given CAM must therefore be considered in the context of the history of the cell expressing it and the repertoire of molecules expressed both by that cell and its neighbors.
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Affiliation(s)
- Nicholas J Gibson
- Department of Neuroscience, University of Arizona, Tucson, Arizona, USA.
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21
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Flotillin-mediated endocytic events dictate cell type-specific responses to semaphorin 3A. J Neurosci 2010; 30:15317-29. [PMID: 21068336 DOI: 10.1523/jneurosci.1821-10.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cortical efferents growing in the same environment diverge early in development. The expression of particular transcription factors dictates the trajectories taken, presumably by regulating responsiveness to guidance cues via cellular mechanisms that are not yet known. Here, we show that cortical neurons that are dissociated and grown in culture maintain their cell type-specific identities defined by the expression of transcription factors. Using this model system, we sought to identify and characterize mechanisms that are recruited to produce cell type-specific responses to Semaphorin 3A (Sema3A), a guidance cue that would be presented similarly to cortical axons in vivo. Axons from presumptive corticofugal neurons lacking the transcription factor Satb2 and expressing Ctip2 or Tbr1 respond far more robustly to Sema3A than those from presumptive callosal neurons expressing Satb2. Both populations of axons express similar levels of Sema3A receptors (neuropilin-1, cell adhesion molecule L1, and plexinA4), but significantly, axons from neurons lacking Satb2 internalize more Sema3A, and they do so via a raft-mediated endocytic pathway. We used an in silico approach to identify the endocytosis effector flotillin-1 as a Sema3A signaling candidate. We tested the contributions of flotillin-1 to Sema3A endocytosis and signaling, and show that raft-mediated Sema3A endocytosis is defined by and depends on the recruitment of flotillin-1, which mediates LIM domain kinase activation and regulates axon responsiveness to Sema3A in presumptive corticofugal axons.
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22
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Abstract
Wiring of the brain relies initially on the correct outgrowth of axons to reach the appropriate target area for innervation. A large number of guidance receptors present in the plasma membrane of axonal growth cones and elsewhere on the neuron read and execute directional cues present in the extracellular environment of the navigating growth cone. The exact timing, levels, and localization of expression of the guidance receptors in the plasma membrane therefore determine the outcome of guidance decisions. Many guidance receptors are localized in exquisitely precise spatial and temporal patterns. The cellular mechanisms ensuring these localization patterns include spatially accurate sorting after synthesis in the secretory pathway, retrieval of inappropriately expressed receptors by endocytosis followed by degradation or recycling, and restriction of diffusion. This article will discuss the machinery and regulation underlying the restricted distribution of membrane receptors, focusing on the currently best-studied example, the L1 cell adhesion molecule. In addition to the long-range mechanisms ensuring appropriate localization, the same mechanisms can act locally to adjust levels and localization of receptors. These local mechanisms are regulated by ligand binding and subsequent activation of local signaling cascades. It is likely that the localization of all guidance receptors is regulated by a combination of sorting, retrieval, recycling and retention, similar to the ones we discuss here for L1.
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Affiliation(s)
- Bettina Winckler
- University of Virginia, Department of Neuroscience, Charlottesville, Virgina 22908, USA
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23
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Gavert N, Ben-Shmuel A, Lemmon V, Brabletz T, Ben-Ze'ev A. Nuclear factor-kappaB signaling and ezrin are essential for L1-mediated metastasis of colon cancer cells. J Cell Sci 2010; 123:2135-43. [PMID: 20501702 DOI: 10.1242/jcs.069542] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hyperactivation of beta-catenin-T-cell-factor (TCF)-regulated gene transcription is a hallmark of colorectal cancer (CRC). The cell-neural adhesion molecule L1CAM (hereafter referred to as L1) is a target of beta-catenin-TCF, exclusively expressed at the CRC invasive front in humans. L1 overexpression in CRC cells increases cell growth and motility, and promotes liver metastasis. Genes induced by L1 are also expressed in human CRC tissue but the mechanisms by which L1 confers metastasis are still unknown. We found that signaling by the nuclear factor kappaB (NF-kappaB) is essential, because inhibition of signaling by the inhibitor of kappaB super repressor (IkappaB-SR) blocked L1-mediated metastasis. Overexpression of the NF-kappaB p65 subunit was sufficient to increase CRC cell proliferation, motility and metastasis. Binding of the L1 cytodomain to ezrin - a cytoskeleton-crosslinking protein - is necessary for metastasis because when binding to L1 was interrupted or ezrin gene expression was suppressed with specific shRNA, metastasis did not occur. L1 and ezrin bound to and mediated the phosphorylation of IkappaB. We also observed a complex containing IkappaB, L1 and ezrin in the juxtamembrane region of CRC cells. Furthermore, we found that L1, ezrin and phosphorylated p65 are co-expressed at the invasive front in human CRC tissue, indicating that L1-mediated activation of NF-kappaB signaling involving ezrin is a major route of CRC progression.
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Affiliation(s)
- Nancy Gavert
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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24
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Nakamura Y, Lee S, Haddox CL, Weaver EJ, Lemmon VP. Role of the cytoplasmic domain of the L1 cell adhesion molecule in brain development. J Comp Neurol 2010; 518:1113-32. [PMID: 20127821 DOI: 10.1002/cne.22267] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Mutations in the human L1CAM gene cause X-linked hydrocephalus and MASA (Mental retardation, Aphasia, Shuffling gait, Adducted thumbs) syndrome. In vitro studies have shown that the L1 cytoplasmic domain (L1CD) is involved in L1 trafficking, neurite branching, signaling, and interactions with the cytoskeleton. L1cam knockout (L1(KO)) mice have hydrocephalus, a small cerebellum, hyperfasciculation of corticothalamic tracts, and abnormal peripheral nerves. To explore the function of the L1CD, we made three new mice lines in which different parts of the L1CD have been altered. In all mutant lines L1 protein is expressed and transported into the axon. Interestingly, these new L1CD mutant lines display normal brain morphology. However, the expression of L1 protein in the adult is dramatically reduced in the two L1CD mutant lines that lack the ankyrin-binding region and they show defects in motor function. Therefore, the L1CD is not responsible for the major defects observed in L1(KO) mice, yet it is required for continued L1 protein expression and motor function in the adult.
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Affiliation(s)
- Yukiko Nakamura
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
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25
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Conant K, Wang Y, Szklarczyk A, Dudak A, Mattson MP, Lim ST. Matrix metalloproteinase-dependent shedding of intercellular adhesion molecule-5 occurs with long-term potentiation. Neuroscience 2010; 166:508-21. [PMID: 20045450 PMCID: PMC3535483 DOI: 10.1016/j.neuroscience.2009.12.061] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 12/22/2009] [Accepted: 12/23/2009] [Indexed: 12/21/2022]
Abstract
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that can be released or activated in a neuronal activity dependent manner. Although pathologically elevated levels of MMPs may be synaptotoxic, physiologically appropriate levels of MMPs may instead enhance synaptic transmission. MMP inhibitors can block long term potentiation (LTP), and at least one family member can affect an increase in the volume of dendritic spines. While the mechanism by which MMPs affect these changes is not completely understood, one possibility is that the cleavage of specific synaptic cell adhesion molecules plays a role. In the present study, we have examined the ability of neuronal activity to stimulate rapid MMP dependent shedding of the intercellular adhesion molecule-5 (ICAM-5), a synaptic adhesion molecule that is thought to inhibit the maturation and enlargement of dendritic spines. Since such cleavage would likely occur within minutes if it were relevant to a process such as LTP, we focused on post stimulus time points of 30 min or less. We show that NMDA can stimulate rapid shedding of ICAM-5 from cortical neurons in dissociated cell cultures and that such shedding is diminished by pretreatment of cultures with inhibitors that target MMP-3 and -9, proteases thought to influence synaptic plasticity. Additional studies suggest that MMP mediated cleavage of ICAM-5 occurs at amino acid 780, so that the major portion of the ectodomain is released. Since reductions in ICAM-5 have been linked to changes in dendritic spine morphology that are associated with LTP, we also examined the possibility that MMP dependent ICAM-5 shedding occurs following high frequency tetanic stimulation of murine hippocampal slices. Results show that the shedding of ICAM-5 occurs in association with LTP, and that both LTP and the associated ICAM-5 shedding are reduced when slices are pretreated with an MMP inhibitor. Together, these findings suggest that neuronal activity is linked to the shedding of a molecule that may inhibit dendritic spine enlargement and that MMPs can affect this change. While further studies will be necessary to determine the extent to which cleavage of ICAM-5 in particular contributes to MMP dependent LTP, our data support an emerging body of literature suggesting that MMPs are critical mediators of synaptic plasticity.
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Affiliation(s)
- Katherine Conant
- Department of Neurology, Johns Hopkins University, Baltimore, MD
- Department of Neuroscience, Georgetown University, Washington, DC
| | - Yue Wang
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD
| | - Arek Szklarczyk
- Department of Neurology, Johns Hopkins University, Baltimore, MD
| | - Amanda Dudak
- Department of Neuroscience, Georgetown University, Washington, DC
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging, Baltimore, MD
| | - Seung T. Lim
- Department of Neuroscience, Georgetown University, Washington, DC
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26
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Tsoory M, Guterman A, Richter-Levin G. âJuvenile stressâ alters maturation-related changes in expression of the neural cell adhesion molecule L1 in the limbic system: Relevance for stress-related psychopathologies. J Neurosci Res 2010; 88:369-80. [DOI: 10.1002/jnr.22203] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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27
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Giannone G, Mège RM, Thoumine O. Multi-level molecular clutches in motile cell processes. Trends Cell Biol 2009; 19:475-86. [PMID: 19716305 DOI: 10.1016/j.tcb.2009.07.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 07/01/2009] [Accepted: 07/02/2009] [Indexed: 01/09/2023]
Abstract
To trigger cell motility, forces generated by the cytoskeleton must be transmitted physically to the external environment through transmembrane adhesion molecules. One model put forward twenty years ago to describe this process is the molecular clutch by which a modular interface of adaptor proteins mediates a dynamic mechanical connection between the actin flow and cell adhesion complexes. Recent optical imaging experiments have identified key clutch molecules linked to specific chemical and mechanical signal transduction pathways, particularly regarding integrins in migrating cells, IgCAMs in neuronal growth cones, and cadherins at intercellular junctions. We propose here the concept of a multi-level clutch as a useful analogy to grasp the complexity of the dynamic molecular interactions involved in a panel of motile behaviors and shapes.
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Affiliation(s)
- Grégory Giannone
- CNRS UMR 5091, Institut Magendie, Université Bordeaux 2, 33077 Bordeaux, France
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28
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Abstract
The L1 family of CAMs (cell adhesion molecules) has long aroused the interest of researchers, but primarily the extracellular interactions of these proteins have been elucidated. More recently, attention has turned to the intracellular signalling potentiated by transmembrane proteins and the cytoplasmic proteins with which they can interact. The present review brings up to date the current body of published knowledge for the intracellular interactions of L1-CAM family proteins and the potential importance of these interactions for the mechanisms of L1-CAM action.
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