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Sciandra F, Desiderio C, Vincenzoni F, Viscuso S, Bozzi M, Hübner W, Jimenez-Gutierrez GE, Cisneros B, Brancaccio A. Analysis of the GFP-labelled β-dystroglycan interactome in HEK-293 transfected cells reveals novel intracellular networks. Biochem Biophys Res Commun 2024; 703:149656. [PMID: 38364681 DOI: 10.1016/j.bbrc.2024.149656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/19/2024] [Accepted: 02/06/2024] [Indexed: 02/18/2024]
Abstract
Dystroglycan (DG) is a cell adhesion complex that is widely expressed in tissues. It is composed by two subunits, α-DG, a highly glycosylated protein that interacts with several extracellular matrix proteins, and transmembrane β-DG whose, cytodomain binds to the actin cytoskeleton. Glycosylation of α-DG is crucial for functioning as a receptor for its multiple extracellular binding partners. Perturbation of α-DG glycosylation is the central event in the pathogenesis of severe pathologies such as muscular dystrophy and cancer. β-DG acts as a scaffold for several cytoskeletal and nuclear proteins and very little is known about the fine regulation of some of these intracellular interactions and how they are perturbed in diseases. To start filling this gap by identifying uncharacterized intracellular networks preferentially associated with β-DG, HEK-293 cells were transiently transfected with a plasmid carrying the β-DG subunit with GFP fused at its C-terminus. With this strategy, we aimed at forcing β-DG to occupy multiple intracellular locations instead of sitting tightly at its canonical plasma membrane milieu, where it is commonly found in association with α-DG. Immunoprecipitation by anti-GFP antibodies followed by shotgun proteomic analysis led to the identification of an interactome formed by 313 exclusive protein matches for β-DG binding. A series of already known β-DG interactors have been found, including ezrin and emerin, whilst significant new matches, which include potential novel β-DG interactors and their related networks, were identified in diverse subcellular compartments, such as cytoskeleton, endoplasmic reticulum/Golgi, mitochondria, nuclear membrane and the nucleus itself. Of particular interest amongst the novel identified matches, Lamina-Associated Polypeptide-1B (LAP1B), an inner nuclear membrane protein, whose mutations are known to cause nuclear envelopathies characterized by muscular dystrophy, was found to interact with β-DG in HEK-293 cells. This evidence was confirmed by immunoprecipitation, Western blotting and immunofluorescence experiments. We also found by immunofluorescence experiments that LAP1B looses its nuclear envelope localization in C2C12 DG-knock-out cells, suggesting that LAP1B requires β-DG for a proper nuclear localization. These results expand the role of β-DG as a nuclear scaffolding protein and provide novel evidence of a possible link between dystroglycanopathies and nuclear envelopathies displaying with muscular dystrophy.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy
| | - Claudia Desiderio
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy
| | - Federica Vincenzoni
- Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Roma, Italy
| | - Simona Viscuso
- Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy; Dipartimento di Scienze biotecnologiche di base, cliniche intensivologiche e perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168, Roma, Italy
| | - Wolfgang Hübner
- Biomolecular Photonics, University of Bielefeld, 33615, Bielefeld, Germany
| | | | - Bulmaro Cisneros
- Departamento de Genética y Biología Molecular, CINVESTAV Zacatenco IPN, Ciudad de México, 07360, Mexico
| | - Andrea Brancaccio
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta"- SCITEC (CNR), Largo F. Vito, 00168, Roma, Italy; School of Biochemistry, University of Bristol, BS8 1TD, UK.
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Sciandra F, Bozzi M, Bigotti MG. From adhesion complex to signaling hub: the dual role of dystroglycan. Front Mol Biosci 2023; 10:1325284. [PMID: 38155958 PMCID: PMC10752950 DOI: 10.3389/fmolb.2023.1325284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 11/27/2023] [Indexed: 12/30/2023] Open
Abstract
Dystroglycan (DG) is a transmembrane protein widely expressed in multiple cells and tissues. It is formed by two subunits, α- and β-DG, and represents a molecular bridge between the outside and the inside of the cell, which is essential for the mechanical and structural stability of the plasma membrane. The α-subunit is a cell-surface protein that binds to the extracellular matrix (ECM) and is tightly associated with the plasma membrane via a non-covalent interaction with the β-subunit, which, in turn, is a transmembrane protein that binds to the cytoskeletal actin. DG is a versatile molecule acting not only as a mechanical building block but also as a modulator of outside-inside signaling events. The cytoplasmic domain of β-DG interacts with different adaptor and cytoskeletal proteins that function as molecular switches for the transmission of ECM signals inside the cells. These interactions can modulate the involvement of DG in different biological processes, ranging from cell growth and survival to differentiation and proliferation/regeneration. Although the molecular events that characterize signaling through the ECM-DG-cytoskeleton axis are still largely unknown, in recent years, a growing list of evidence has started to fill the gaps in our understanding of the role of DG in signal transduction. This mini-review represents an update of recent developments, uncovering the dual role of DG as an adhesion and signaling molecule that might inspire new ideas for the design of novel therapeutic strategies for pathologies such as muscular dystrophy, cardiomyopathy, and cancer, where the DG signaling hub plays important roles.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”-SCITEC (CNR), Roma, Italy
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica, Università Cattolica del Sacro Cuore di Roma, Roma, Italy
| | - Maria Giulia Bigotti
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
- Bristol Heart Institute, Research Floor Level 7, Bristol Royal Infirmary, Bristol, United Kingdom
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Quereda C, Pastor À, Martín-Nieto J. Involvement of abnormal dystroglycan expression and matriglycan levels in cancer pathogenesis. Cancer Cell Int 2022; 22:395. [PMID: 36494657 PMCID: PMC9733019 DOI: 10.1186/s12935-022-02812-7] [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: 08/24/2022] [Accepted: 11/28/2022] [Indexed: 12/13/2022] Open
Abstract
Dystroglycan (DG) is a glycoprotein composed of two subunits that remain non-covalently bound at the plasma membrane: α-DG, which is extracellular and heavily O-mannosyl glycosylated, and β-DG, an integral transmembrane polypeptide. α-DG is involved in the maintenance of tissue integrity and function in the adult, providing an O-glycosylation-dependent link for cells to their extracellular matrix. β-DG in turn contacts the cytoskeleton via dystrophin and participates in a variety of pathways transmitting extracellular signals to the nucleus. Increasing evidence exists of a pivotal role of DG in the modulation of normal cellular proliferation. In this context, deficiencies in DG glycosylation levels, in particular those affecting the so-called matriglycan structure, have been found in an ample variety of human tumors and cancer-derived cell lines. This occurs together with an underexpression of the DAG1 mRNA and/or its α-DG (core) polypeptide product or, more frequently, with a downregulation of β-DG protein levels. These changes are in general accompanied in tumor cells by a low expression of genes involved in the last steps of the α-DG O-mannosyl glycosylation pathway, namely POMT1/2, POMGNT2, CRPPA, B4GAT1 and LARGE1/2. On the other hand, a series of other genes acting earlier in this pathway are overexpressed in tumor cells, namely DOLK, DPM1/2/3, POMGNT1, B3GALNT2, POMK and FKTN, hence exerting instead a pro-oncogenic role. Finally, downregulation of β-DG, altered β-DG processing and/or impaired β-DG nuclear levels are increasingly found in human tumors and cell lines. It follows that DG itself, particular genes/proteins involved in its glycosylation and/or their interactors in the cell could be useful as biomarkers of certain types of human cancer, and/or as molecular targets of new therapies addressing these neoplasms.
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Affiliation(s)
- Cristina Quereda
- grid.5268.90000 0001 2168 1800Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Campus Universitario San Vicente, P.O. Box 99, 03080 Alicante, Spain
| | - Àngels Pastor
- grid.5268.90000 0001 2168 1800Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Campus Universitario San Vicente, P.O. Box 99, 03080 Alicante, Spain
| | - José Martín-Nieto
- grid.5268.90000 0001 2168 1800Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, Campus Universitario San Vicente, P.O. Box 99, 03080 Alicante, Spain ,grid.5268.90000 0001 2168 1800Instituto Multidisciplinar para el Estudio del Medio ‘Ramón Margalef’, Universidad de Alicante, 03080 Alicante, Spain
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Basu A, Mahammad A, Das A. Inhibition of the formation of lysozyme fibrillar assemblies by the isoquinoline alkaloid coralyne. NEW J CHEM 2022. [DOI: 10.1039/d1nj06007d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The isoquinoline alkaloid coralyne can efficiently attenuate fibrillogenesis in lysozyme.
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Affiliation(s)
- Anirban Basu
- Department of Chemistry, Vidyasagar University, Midnapore 721 102, India
| | - Adil Mahammad
- Department of Chemistry, Vidyasagar University, Midnapore 721 102, India
| | - Arindam Das
- Department of Chemistry, Vidyasagar University, Midnapore 721 102, India
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MMP-9 Signaling Pathways That Engage Rho GTPases in Brain Plasticity. Cells 2021; 10:cells10010166. [PMID: 33467671 PMCID: PMC7830260 DOI: 10.3390/cells10010166] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/12/2021] [Accepted: 01/12/2021] [Indexed: 02/08/2023] Open
Abstract
The extracellular matrix (ECM) has been identified as a critical factor affecting synaptic function. It forms a functional scaffold that provides both the structural support and the reservoir of signaling molecules necessary for communication between cellular constituents of the central nervous system (CNS). Among numerous ECM components and modifiers that play a role in the physiological and pathological synaptic plasticity, matrix metalloproteinase 9 (MMP-9) has recently emerged as a key molecule. MMP-9 may contribute to the dynamic remodeling of structural and functional plasticity by cleaving ECM components and cell adhesion molecules. Notably, MMP-9 signaling was shown to be indispensable for long-term memory formation that requires synaptic remodeling. The core regulators of the dynamic reorganization of the actin cytoskeleton and cell adhesion are the Rho family of GTPases. These proteins have been implicated in the control of a wide range of cellular processes occurring in brain physiology and pathology. Here, we discuss the contribution of Rho GTPases to MMP-9-dependent signaling pathways in the brain. We also describe how the regulation of Rho GTPases by post-translational modifications (PTMs) can influence these processes.
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Noël G, Tham DKL, Guadagno E, MacVicar B, Moukhles H. The Laminin-Induced Phosphorylation of PKCδ Regulates AQP4 Distribution and Water Permeability in Rat Astrocytes. Cell Mol Neurobiol 2020; 41:1743-1757. [PMID: 32851539 DOI: 10.1007/s10571-020-00944-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 08/14/2020] [Indexed: 11/29/2022]
Abstract
In astrocytes, the water-permeable channel aquaporin-4 (AQP4) is concentrated at the endfeet that abut the blood vessels of the brain. The asymmetric distribution of this channel is dependent on the function of dystroglycan (DG), a co-expressed laminin receptor, and its associated protein complex. We have demonstrated that the addition of laminin to astrocytes in culture causes the clustering of AQP4, DG, and lipid rafts. The last, in particular, have been associated with the initiation of cell signaling. As laminin binding to DG in muscle cells can induce the tyrosine phosphorylation of syntrophin and laminin requires tyrosine kinases for acetylcholine receptor clustering in myotubes, we asked if signal transduction might also be involved in AQP4 clustering in astrocytes. We analyzed the timecourse of AQP4, DG, and monosialotetrahexosylganglioside (GM1) clustering in primary cultures of rat astrocytes following the addition of laminin, and determined that the clustering of DG precedes that of AQP4 and GM1. We also showed that laminin induces the formation of phosphotyrosine-rich clusters and that the tyrosine kinase inhibitor, genistein, disrupts the laminin-induced clustering of both β-DG and AQP4. Using the Kinexus antibody microarray chip, we then identified protein-serine kinase C delta (PKCδ) as one of the main proteins exhibiting high levels of tyrosine phosphorylation upon laminin treatment. Selective inhibitors of PKC and siRNA against PKCδ disrupted β-DG and AQP4 clustering, and also caused water transport to increase in astrocytes treated with laminin. Our results demonstrate that the effects of laminin on AQP4 localization and function are relayed, at least in part, through PKC signaling.
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Affiliation(s)
- Geoffroy Noël
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Daniel Kai Long Tham
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Eric Guadagno
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada
| | - Brian MacVicar
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Hakima Moukhles
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, V6T 1Z3, Canada.
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Gioia M, Fasciglione GF, Sbardella D, Sciandra F, Casella M, Camerini S, Crescenzi M, Gori A, Tarantino U, Cozza P, Brancaccio A, Coletta M, Bozzi M. The enzymatic processing of α-dystroglycan by MMP-2 is controlled by two anchoring sites distinct from the active site. PLoS One 2018; 13:e0192651. [PMID: 29447293 PMCID: PMC5813964 DOI: 10.1371/journal.pone.0192651] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/26/2018] [Indexed: 11/19/2022] Open
Abstract
Dystroglycan (DG) is a membrane receptor, belonging to the dystrophin-glycoprotein complex (DGC) and formed by two subunits, α-dystroglycan (α-DG) and β-dystroglycan (β -DG). The C-terminal domain of α-DG and the N-terminal extracellular domain of β -DG are connected, providing a link between the extracellular matrix and the cytosol. Under pathological conditions, such as cancer and muscular dystrophies, DG may be the target of metalloproteinases MMP-2 and MMP-9, contributing to disease progression. Previously, we reported that the C-terminal domain α-DG (483–628) domain is particularly susceptible to the catalytic activity of MMP-2; here we show that the α-DG 621–628 region is required to carry out its complete digestion, suggesting that this portion may represent a MMP-2 anchoring site. Following this observation, we synthesized an α-DG based-peptide, spanning the (613–651) C-terminal region. The analysis of the kinetic and thermodynamic parameters of the whole and the isolated catalytic domain of MMP-2 (cdMMP-2) has shown its inhibitory properties, indicating the presence of (at least) two binding sites for the peptide, both located within the catalytic domain, only one of the two being topologically distinct from the catalytic active groove. However, the different behavior between whole MMP-2 and cdMMP-2 envisages the occurrence of an additional binding site for the peptide on the hemopexin-like domain of MMP-2. Interestingly, mass spectrometry analysis has shown that α-DG (613–651) peptide is cleavable even though it is a very poor substrate of MMP-2, a feature that renders this molecule a promising template for developing a selective MMP-2 inhibitor.
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Affiliation(s)
- Magda Gioia
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
- CIRCMSB, Bari, Italy
- * E-mail: (MG); (MB)
| | - Giovanni Francesco Fasciglione
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
- CIRCMSB, Bari, Italy
| | - Diego Sbardella
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
- CIRCMSB, Bari, Italy
| | | | | | | | | | | | - Umberto Tarantino
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
| | - Paola Cozza
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
| | - Andrea Brancaccio
- CNR Institute for Molecular Recognition, Roma Italy
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma Tor Vergata, Roma, Italy
- CIRCMSB, Bari, Italy
| | - Manuela Bozzi
- CNR Institute for Molecular Recognition, Roma Italy
- Institute of Biochemistry and Clinical Biochemistry, Catholic University, Roma Italy
- * E-mail: (MG); (MB)
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8
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Signorino G, Covaceuszach S, Bozzi M, Hübner W, Mönkemöller V, Konarev PV, Cassetta A, Brancaccio A, Sciandra F. A dystroglycan mutation (p.Cys667Phe) associated to muscle-eye-brain disease with multicystic leucodystrophy results in ER-retention of the mutant protein. Hum Mutat 2017; 39:266-280. [PMID: 29134705 DOI: 10.1002/humu.23370] [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: 08/07/2017] [Revised: 10/13/2017] [Accepted: 11/06/2017] [Indexed: 01/11/2023]
Abstract
Dystroglycan (DG) is a cell adhesion complex composed by two subunits, the highly glycosylated α-DG and the transmembrane β-DG. In skeletal muscle, DG is involved in dystroglycanopathies, a group of heterogeneous muscular dystrophies characterized by a reduced glycosylation of α-DG. The genes mutated in secondary dystroglycanopathies are involved in the synthesis of O-mannosyl glycans and in the O-mannosylation pathway of α-DG. Mutations in the DG gene (DAG1), causing primary dystroglycanopathies, destabilize the α-DG core protein influencing its binding to modifying enzymes. Recently, a homozygous mutation (p.Cys699Phe) hitting the β-DG ectodomain has been identified in a patient affected by muscle-eye-brain disease with multicystic leucodystrophy, suggesting that other mechanisms than hypoglycosylation of α-DG could be implicated in dystroglycanopathies. Herein, we have characterized the DG murine mutant counterpart by transfection in cellular systems and high-resolution microscopy. We observed that the mutation alters the DG processing leading to retention of its uncleaved precursor in the endoplasmic reticulum. Accordingly, small-angle X-ray scattering data, corroborated by biochemical and biophysical experiments, revealed that the mutation provokes an alteration in the β-DG ectodomain overall folding, resulting in disulfide-associated oligomerization. Our data provide the first evidence of a novel intracellular mechanism, featuring an anomalous endoplasmic reticulum-retention, underlying dystroglycanopathy.
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Affiliation(s)
- Giulia Signorino
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | | | - Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy.,Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Wolfgang Hübner
- Biomolecular Photonics, University of Bielefeld, Bielefeld, Germany
| | | | - Petr V Konarev
- A.V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics" of Russian Academy of Sciences, Leninsky prospect 59, Moscow, Russia
| | - Alberto Cassetta
- Istituto di Cristallografia - CNR, Trieste Outstation, Trieste, Italy
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy.,School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare - CNR c/o Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
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Palmieri V, Bozzi M, Signorino G, Papi M, De Spirito M, Brancaccio A, Maulucci G, Sciandra F. α-Dystroglycan hypoglycosylation affects cell migration by influencing β-dystroglycan membrane clustering and filopodia length: A multiscale confocal microscopy analysis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2182-2191. [DOI: 10.1016/j.bbadis.2017.05.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 05/05/2017] [Accepted: 05/28/2017] [Indexed: 12/26/2022]
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10
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Chong X, Sun L, Sun Y, Chang L, Chang AK, Lu X, Zhou X, Liu J, Zhang B, Jones GW, He J. Insights into the mechanism of how Morin suppresses amyloid fibrillation of hen egg white lysozyme. Int J Biol Macromol 2017; 101:321-325. [PMID: 28341174 DOI: 10.1016/j.ijbiomac.2017.03.107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 03/17/2017] [Accepted: 03/20/2017] [Indexed: 12/20/2022]
Abstract
This communication describes the inhibitory effect of Morin on the fibrillation of Hen Egg White Lysozyme (HEWL), a generic amyloid-forming model protein. This effect was dose-dependent and stronger than other small molecules we have tested previously. Spectrofluorometric and computational studies support a model suggesting that Morin inhibits amyloid fibril formation of HEWL by binding to the aggregation prone cleft region of the β-domain of HEWL, thereby stabilizing the molecule in its native-like state. Interestingly, transmission electron microscopy observations suggest that, along with increases in Morin concentration, the observed amorphous aggregates became larger and morphologically different. We propose that following occupation of the binding cleft, excess Morin adheres and coats the HEWL protein surface, thereby minimizing the interaction between the protein surface and water molecules.
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Affiliation(s)
- Xiaoying Chong
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Luchen Sun
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Yonghui Sun
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Lin Chang
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Alan K Chang
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Xian Lu
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Xuejie Zhou
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Junqing Liu
- School of Life Science, Liaoning University, Shenyang 110036, China
| | - Bing Zhang
- Experimental Center of Functional Subjects, China Medical University, 92 Bei Er Road, Heping District, Shenyang 110001, China
| | - Gary W Jones
- Centre for Biomedical Science Research, School of Clinical and Applied Sciences, Leeds Beckett University, City Campus, Leeds LS1 3HE, United Kingdom
| | - Jianwei He
- School of Life Science, Liaoning University, Shenyang 110036, China.
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Cerecedo D, Martínez-Vieyra I, Sosa-Peinado A, Cornejo-Garrido J, Ordaz-Pichardo C, Benítez-Cardoza C. Alterations in plasma membrane promote overexpression and increase of sodium influx through epithelial sodium channel in hypertensive platelets. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1891-903. [PMID: 27137675 DOI: 10.1016/j.bbamem.2016.04.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 03/31/2016] [Accepted: 04/27/2016] [Indexed: 12/30/2022]
Abstract
Platelets are small, anucleated cell fragments that activate in response to a wide variety of stimuli, triggering a complex series of intracellular pathways leading to a hemostatic thrombus formation at vascular injury sites. However, in essential hypertension, platelet activation contributes to causing myocardial infarction and ischemic stroke. Reported abnormalities in platelet functions, such as platelet hyperactivity and hyperaggregability to several agonists, contribute to the pathogenesis and complications of thrombotic events associated with hypertension. Platelet membrane lipid composition and fluidity are determining for protein site accessibility, structural arrangement of platelet surface, and response to appropriate stimuli. The present study aimed to demonstrate whether structural and biochemical abnormalities in lipid membrane composition and fluidity characteristic of platelets from hypertensive patients influence the expression of the Epithelial Sodium Channel (ENaC), fundamental for sodium influx during collagen activation. Wb, cytometry and quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) assays demonstrated ENaC overexpression in platelets from hypertensive subjects and in relation to control subjects. Additionally, our results strongly suggest a key role of β-dystroglycan as a scaffold for the organization of ENaC and associated proteins. Understanding of the mechanisms of platelet alterations in hypertension should provide valuable information for the pathophysiology of hypertension.
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Affiliation(s)
- D Cerecedo
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), México City, México.
| | - Ivette Martínez-Vieyra
- Laboratorio de Hematobiología, Escuela Nacional de Medicina y Homeopatía (ENMH), Instituto Politécnico Nacional (IPN), México City, México
| | - Alejandro Sosa-Peinado
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), P.O. Box 70-159, 04510, D.F., México City, México
| | - Jorge Cornejo-Garrido
- Laboratorio de Biología Celular y Productos Naturales, ENMH, IPN, México City, México
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Dystrophin complex functions as a scaffold for signalling proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:635-42. [DOI: 10.1016/j.bbamem.2013.08.023] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/22/2013] [Accepted: 08/28/2013] [Indexed: 11/23/2022]
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Johnson EK, Li B, Yoon JH, Flanigan KM, Martin PT, Ervasti J, Montanaro F. Identification of new dystroglycan complexes in skeletal muscle. PLoS One 2013; 8:e73224. [PMID: 23951345 PMCID: PMC3738564 DOI: 10.1371/journal.pone.0073224] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/18/2013] [Indexed: 01/16/2023] Open
Abstract
The dystroglycan complex contains the transmembrane protein β-dystroglycan and its interacting extracellular mucin-like protein α-dystroglycan. In skeletal muscle fibers, the dystroglycan complex plays an important structural role by linking the cytoskeletal protein dystrophin to laminin in the extracellular matrix. Mutations that affect any of the proteins involved in this structural axis lead to myofiber degeneration and are associated with muscular dystrophies and congenital myopathies. Because loss of dystrophin in Duchenne muscular dystrophy (DMD) leads to an almost complete loss of dystroglycan complexes at the myofiber membrane, it is generally assumed that the vast majority of dystroglycan complexes within skeletal muscle fibers interact with dystrophin. The residual dystroglycan present in dystrophin-deficient muscle is thought to be preserved by utrophin, a structural homolog of dystrophin that is up-regulated in dystrophic muscles. However, we found that dystroglycan complexes are still present at the myofiber membrane in the absence of both dystrophin and utrophin. Our data show that only a minority of dystroglycan complexes associate with dystrophin in wild type muscle. Furthermore, we provide evidence for at least three separate pools of dystroglycan complexes within myofibers that differ in composition and are differentially affected by loss of dystrophin. Our findings indicate a more complex role of dystroglycan in muscle than currently recognized and may help explain differences in disease pathology and severity among myopathies linked to mutations in DAPC members.
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Affiliation(s)
- Eric K. Johnson
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, the Ohio State University, Columbus, Ohio, United States of America
| | - Bin Li
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Jung Hae Yoon
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
| | - Kevin M. Flanigan
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Paul T. Martin
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - James Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Federica Montanaro
- Center for Gene Therapy, the Research Institute at Nationwide Children’s Hospital, and The Ohio State University Biochemistry Program, Columbus, Ohio, United States of America
- Ohio State Biochemistry Program, the Ohio State University, Columbus, Ohio, United States of America
- Department of Pediatrics, the Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
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Van Roey K, Dinkel H, Weatheritt RJ, Gibson TJ, Davey NE. The switches.ELM resource: a compendium of conditional regulatory interaction interfaces. Sci Signal 2013; 6:rs7. [PMID: 23550212 DOI: 10.1126/scisignal.2003345] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Short linear motifs (SLiMs) are protein interaction sites that play an important role in cell regulation by controlling protein activity, localization, and local abundance. The functionality of a SLiM can be modulated in a context-dependent manner to induce a gain, loss, or exchange of binding partners, which will affect the function of the SLiM-containing protein. As such, these conditional interactions underlie molecular decision-making in cell signaling. We identified multiple types of pre- and posttranslational switch mechanisms that can regulate the function of a SLiM and thereby control its interactions. The collected examples of experimentally characterized SLiM-based switch mechanisms were curated in the freely accessible switches.ELM resource (http://switches.elm.eu.org). On the basis of these examples, we defined and integrated rules to analyze SLiMs for putative regulatory switch mechanisms. We applied these rules to known validated SLiMs, providing evidence that more than half of these are likely to be pre- or posttranslationally regulated. In addition, we showed that posttranslationally modified sites are enriched around SLiMs, which enables cooperative and integrative regulation of protein interaction interfaces. We foresee switches.ELM complementing available resources to extend our knowledge of the molecular mechanisms underlying cell signaling.
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Affiliation(s)
- Kim Van Roey
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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Mallozzi C, D'Amore C, Camerini S, Macchia G, Crescenzi M, Petrucci TC, Di Stasi AMM. Phosphorylation and nitration of tyrosine residues affect functional properties of Synaptophysin and Dynamin I, two proteins involved in exo-endocytosis of synaptic vesicles. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:110-21. [DOI: 10.1016/j.bbamcr.2012.10.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 10/08/2012] [Accepted: 10/21/2012] [Indexed: 12/14/2022]
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Abstract
Agrin, an extracellular matrix protein belonging to the heterogeneous family of heparan sulfate proteoglycans (HSPGs), is expressed by cells of the hematopoietic system but its role in leukocyte biology is not yet clear. Here we demonstrate that agrin has a crucial, nonredundant role in myeloid cell development and functions. We have identified lineage-specific alterations that affect maturation, survival and properties of agrin-deficient monocytic cells, and occur at stages later than stem cell precursors. Our data indicate that the cell-autonomous signals delivered by agrin are sensed by macrophages through the α-DC (DG) receptor and lead to the activation of signaling pathways resulting in rearrangements of the actin cytoskeleton during the phagocytic synapse formation and phosphorylation of extracellular signal-regulated kinases (Erk 1/2). Altogether, these data identify agrin as a novel player of innate immunity.
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Jiang X, Rieder S, Giese NA, Friess H, Michalski CW, Kleeff J. Reduced α-Dystroglycan Expression Correlates with Shortened Patient Survival in Pancreatic Cancer. J Surg Res 2011; 171:120-6. [DOI: 10.1016/j.jss.2009.11.730] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/10/2009] [Accepted: 11/20/2009] [Indexed: 02/06/2023]
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The dystrophin-glycoprotein complex in the prevention of muscle damage. J Biomed Biotechnol 2011; 2011:210797. [PMID: 22007139 PMCID: PMC3189583 DOI: 10.1155/2011/210797] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/03/2011] [Indexed: 01/18/2023] Open
Abstract
Muscular dystrophies are genetically diverse but share common phenotypic features of muscle weakness, degeneration, and progressive decline in muscle function. Previous work has focused on understanding how disruptions in the dystrophin-glycoprotein complex result in muscular dystrophy, supporting a hypothesis that the muscle sarcolemma is fragile and susceptible to contraction-induced injury in multiple forms of dystrophy. Although benign in healthy muscle, contractions in dystrophic muscle may contribute to a higher degree of muscle damage which eventually overwhelms muscle regeneration capacity. While increased susceptibility of muscle to mechanical injury is thought to be an important contributor to disease pathology, it is becoming clear that not all DGC-associated diseases share this supposed hallmark feature. This paper outlines experimental support for a function of the DGC in preventing muscle damage and examines the evidence that supports novel functions for this complex in muscle that when impaired, may contribute to the pathogenesis of muscular dystrophy.
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Expression of Dystrophins and the Dystrophin-Associated-Protein Complex by Pituicytes in Culture. Neurochem Res 2011; 36:1407-16. [DOI: 10.1007/s11064-011-0466-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/2011] [Indexed: 11/30/2022]
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Galvin J, Eyermann C, Colognato H. Dystroglycan modulates the ability of insulin-like growth factor-1 to promote oligodendrocyte differentiation. J Neurosci Res 2011; 88:3295-307. [PMID: 20857503 DOI: 10.1002/jnr.22484] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The adhesion receptor dystroglycan positively regulates terminal differentiation of oligodendrocytes, but the mechanism by which this occurs remains unclear. Using primary oligodendrocyte cultures, we identified and examined a connection between dystroglycan and the ability of insulin-like growth factor-1 (IGF-1) to promote oligodendrocyte differentiation. Consistent with previous reports, treatment with exogenous IGF-1 caused an increase in MBP protein that was preceded by activation of PI3K (AKT) and MAPK (ERK) signaling pathways. The extracellular matrix protein laminin was further shown to potentiate the effect of IGF-1 on oligodendrocyte differentiation. Depletion of the laminin receptor dystroglycan using siRNA, however, blocked the ability of IGF-1 to promote oligodendrocyte differentiation of cells grown on laminin, suggesting a role for dystroglycan in IGF-1-mediated differentiation. Indeed, loss of dystroglycan led to a reduction in the ability of IGF-1 to activate MAPK, but not PI3K, signaling pathways. Pharmacological inhibition of MAPK signaling also prevented IGF-1-induced increases in myelin basic protein (MBP), indicating that MAPK signaling was necessary to drive IGF-1-mediated enhancement of oligodendrocyte differentiation. Using immunoprecipitation, we found that dystroglycan, the adaptor protein Grb2, and insulin receptor substrate-1 (IRS-1), were associated in a protein complex. Taken together, our results suggest that the positive regulatory effect of laminin on oligodendrocyte differentiation may be attributed, at least in part, to dystroglycan's ability to promote IGF-1-induced differentiation.
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Affiliation(s)
- Jason Galvin
- Department of Pharmacology, Stony Brook University, Stony Brook, New York 11794-8651, USA
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Pinto LC, Fávaro WJ, Cagnon VHA. Proliferative, structural and molecular features of the Mdx mouse prostate. Int J Exp Pathol 2010; 91:408-19. [PMID: 20618884 DOI: 10.1111/j.1365-2613.2010.00722.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The prostate is fundamental to the male reproductive process, and the stroma-epithelium interaction has an important role in prostate maintenance. Studies suggest that dystroglycan (DG) plays a role in cancer development in various organs. Thus, the aims of this work were to characterize morphological and proliferative features of the prostatic stroma and epithelium of mdx mice; to verify the immunolocalization of the α and β DG, IGF-1 and laminin α3 receptors; and to relate those structural and molecular events to prostate pathogenesis and to verify the viability of this experimental model in prostate studies. Thirty male mice (mdx and C57BL10/Uni) were divided into control and mdx groups. Samples from the ventral prostate were collected for immunological, Western Blotting, transmission electron microscopy and morphometric analyses. Oestradiol and testosterone measurements were verified. The results showed diminished testosterone and increased oestradiol levels in the mdx group. Atrophied cells and hypertrophied stroma were seen in the mdx mice. Weak α and β DG and laminin α3 immunolocalization was demonstrated in the mdx group. Intense insulin-like growth factor receptor α-1 (IGFRα-1) localization was identified in the mdx animals. Thus, mdx animals showed changes in molecular and structural integrity and proliferation signals, leading to glandular homoeostasis imbalance, and compromise of prostate function. Also, the steroid hormone imbalance and the increased IGF-1 receptor level detected in mdx mice could be considered as a crucial factor in the pathogenesis of prostatic disorders.
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Affiliation(s)
- Leslie C Pinto
- Department of Anatomy, Cell Biology, Physiology and Biophysic, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, Brazil
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Biological role of dystroglycan in Schwann cell function and its implications in peripheral nervous system diseases. J Biomed Biotechnol 2010; 2010:740403. [PMID: 20625412 PMCID: PMC2896880 DOI: 10.1155/2010/740403] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Accepted: 04/20/2010] [Indexed: 11/17/2022] Open
Abstract
Dystroglycan is a central component of the dystrophin-glycoprotein complex (DGC) that links extracellular matrix with cytoskeleton, expressed in a variety of fetal and adult tissues. Dystroglycan plays diverse roles in development and homeostasis including basement membrane formation, epithelial morphogenesis, membrane stability, cell polarization, and cell migration. In this paper, we will focus on biological role of dystroglycan in Schwann cell function, especially myelination. First, we review the molecular architecture of DGC in Schwann cell abaxonal membrane. Then, we will review the loss-of-function studies using targeted mutagenesis, which have revealed biological functions of each component of DGC in Schwann cells. Based on these findings, roles of dystroglycan in Schwann cell function, in myelination in particular, and its implications in diseases will be discussed in detail. Finally, in view of the fact that understanding the role of dystroglycan in Schwann cells is just beginning, future perspectives will be discussed.
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Artegiani B, Labbaye C, Sferra A, Quaranta MT, Torreri P, Macchia G, Ceccarini M, Petrucci TC, Macioce P. The interaction with HMG20a/b proteins suggests a potential role for beta-dystrobrevin in neuronal differentiation. J Biol Chem 2010; 285:24740-50. [PMID: 20530487 DOI: 10.1074/jbc.m109.090654] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha and beta dystrobrevins are cytoplasmic components of the dystrophin-associated protein complex that are thought to play a role as scaffold proteins in signal transduction and intracellular transport. In the search of new insights into the functions of beta-dystrobrevin, the isoform restricted to non-muscle tissues, we performed a two-hybrid screen of a mouse cDNA library to look for interacting proteins. Among the positive clones, one encodes iBRAF/HMG20a, a high mobility group (HMG)-domain protein that activates REST (RE-1 silencing transcription factor)-responsive genes, playing a key role in the initiation of neuronal differentiation. We characterized the beta-dystrobrevin-iBRAF interaction by in vitro and in vivo association assays, localized the binding region of one protein to the other, and assessed the kinetics of the interaction as one of high affinity. We also found that beta-dystrobrevin directly binds to BRAF35/HMG20b, a close homologue of iBRAF and a member of a co-repressor complex required for the repression of neural specific genes in neuronal progenitors. In vitro assays indicated that beta-dystrobrevin binds to RE-1 and represses the promoter activity of synapsin I, a REST-responsive gene that is a marker for neuronal differentiation. Altogether, our data demonstrate a direct interaction of beta-dystrobrevin with the HMG20 proteins iBRAF and BRAF35 and suggest that beta-dystrobrevin may be involved in regulating chromatin dynamics, possibly playing a role in neuronal differentiation.
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Affiliation(s)
- Benedetta Artegiani
- Department of Cell Biology and Neuroscience, National Center for Rare Diseases, Istituto Superiore di Sanità, Rome 00161, Italy
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Lara-Chacón B, de León MB, Leocadio D, Gómez P, Fuentes-Mera L, Martínez-Vieyra I, Ortega A, Jans DA, Cisneros B. Characterization of an Importin α/β-recognized nuclear localization signal in β-dystroglycan. J Cell Biochem 2010; 110:706-17. [DOI: 10.1002/jcb.22581] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Moore CJ, Winder SJ. Dystroglycan versatility in cell adhesion: a tale of multiple motifs. Cell Commun Signal 2010; 8:3. [PMID: 20163697 PMCID: PMC2834674 DOI: 10.1186/1478-811x-8-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 02/17/2010] [Indexed: 12/02/2022] Open
Abstract
Dystroglycan is a ubiquitously expressed heterodimeric adhesion receptor. The extracellular α-subunit makes connections with a number of laminin G domain ligands including laminins, agrin and perlecan in the extracellular matrix and the transmembrane β-subunit makes connections to the actin filament network via cytoskeletal linkers including dystrophin, utrophin, ezrin and plectin, depending on context. Originally discovered as part of the dystrophin glycoprotein complex of skeletal muscle, dystroglycan is an important adhesion molecule and signalling scaffold in a multitude of cell types and tissues and is involved in several diseases. Dystroglycan has emerged as a multifunctional adhesion platform with many interacting partners associating with its short unstructured cytoplasmic domain. Two particular hotspots are the cytoplasmic juxtamembrane region and at the very carboxy terminus of dystroglycan. Regions which between them have several overlapping functions: in the juxtamembrane region; a nuclear localisation signal, ezrin/radixin/moesin protein, rapsyn and ERK MAP Kinase binding function, and at the C terminus a regulatory tyrosine governing WW, SH2 and SH3 domain interactions. We will discuss the binding partners for these motifs and how their interactions and regulation can modulate the involvement of dystroglycan in a range of different adhesion structures and functions depending on context. Thus dystroglycan presents as a multifunctional scaffold involved in adhesion and adhesion-mediated signalling with its functions under exquisite spatio-temporal regulation.
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Affiliation(s)
- Chris J Moore
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK.
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Yatsenko AS, Kucherenko MM, Pantoja M, Fischer KA, Madeoy J, Deng WM, Schneider M, Baumgartner S, Akey J, Shcherbata HR, Ruohola-Baker H. The conserved WW-domain binding sites in Dystroglycan C-terminus are essential but partially redundant for Dystroglycan function. BMC DEVELOPMENTAL BIOLOGY 2009; 9:18. [PMID: 19250553 PMCID: PMC2660313 DOI: 10.1186/1471-213x-9-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Accepted: 02/27/2009] [Indexed: 11/23/2022]
Abstract
Background Dystroglycan (Dg) is a transmembrane protein that is a part of the Dystrophin Glycoprotein Complex (DGC) which connects the extracellular matrix to the actin cytoskeleton. The C-terminal end of Dg contains a number of putative SH3, SH2 and WW domain binding sites. The most C-terminal PPXY motif has been established as a binding site for Dystrophin (Dys) WW-domain. However, our previous studies indicate that both Dystroglycan PPXY motives, WWbsI and WWbsII can bind Dystrophin protein in vitro. Results We now find that both WW binding sites are important for maintaining full Dg function in the establishment of oocyte polarity in Drosophila. If either WW binding site is mutated, the Dg protein can still be active. However, simultaneous mutations in both WW binding sites abolish the Dg activities in both overexpression and loss-of-function oocyte polarity assays in vivo. Additionally, sequence comparisons of WW binding sites in 12 species of Drosophila, as well as in humans, reveal a high level of conservation. This preservation throughout evolution supports the idea that both WW binding sites are functionally required. Conclusion Based on the obtained results we propose that the presence of the two WW binding sites in Dystroglycan secures the essential interaction between Dg and Dys and might further provide additional regulation for the cytoskeletal interactions of this complex.
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Affiliation(s)
- A S Yatsenko
- Department of Biochemistry, Institute for Stem Cell and Regenerative Medicine, Program in Neurobiology and Behaviour, University of Washington, Seattle, WA 98195, USA.
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Yamamoto T, Kato Y, Shibata N, Sawada T, Osawa M, Kobayashi M. A role of fukutin, a gene responsible for Fukuyama type congenital muscular dystrophy, in cancer cells: a possible role to suppress cell proliferation. Int J Exp Pathol 2008; 89:332-41. [PMID: 18808525 DOI: 10.1111/j.1365-2613.2008.00599.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Fukutin, a gene responsible for Fukuyama type congenital muscular dystrophy (FCMD), is presumably related to the glycosylation of alpha-dystroglycan (alpha-DG), involved in basement membrane formation. Hypoglycosylation of alpha-DG plays a key role for the pathogenesis of FCMD. On the other hand, fukutin and alpha-DG are also expressed in various non-neuromuscular tissues. Recently, a role of alpha-DG as a cancer suppressor has been proposed, because of a decrease of glycosylated alpha-DG in cancers. In this study, function of fukutin was investigated in two cancer cell lines, focusing on whether fukutin is involved in the glycosylation of alpha-DG in cancer cells and has any possible roles related to a cancer suppressor. Localization of fukutin and a result of laminin-binding assay after RNA interference suggest that fukutin may be involved in the glycosylation of alpha-DG in a small portion in these cancer cell lines. In Western blotting and immuno-electron microscopy, localization of fukutin in the nucleus was suggested in addition to the Golgi apparatus and/or endoplasmic reticulum. Immunohistochemically, there were more Ki-67-positive cells and more nuclear staining of phosphorylated c-jun after knockdown of fukutin in two cell lines. Fukutin appears to suppress cell proliferation through a system involving c-jun, although it is unclear this process is related to alpha-DG or not at present. The result may propose a possibility of another function of fukutin in addition to the glycosylation of alpha-DG in cancer cells.
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Affiliation(s)
- Tomoko Yamamoto
- Department of Pathology, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan.
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Martin PT, Shelton GD, Dickinson PJ, Sturges BK, Xu R, LeCouteur RA, Guo LT, Grahn RA, Lo HP, North KN, Malik R, Engvall E, Lyons LA. Muscular dystrophy associated with alpha-dystroglycan deficiency in Sphynx and Devon Rex cats. Neuromuscul Disord 2008; 18:942-52. [PMID: 18990577 DOI: 10.1016/j.nmd.2008.08.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Revised: 07/27/2008] [Accepted: 08/16/2008] [Indexed: 11/28/2022]
Abstract
Recent studies have identified a number of forms of muscular dystrophy, termed dystroglycanopathies, which are associated with loss of natively glycosylated alpha-dystroglycan. Here we identify a new animal model for this class of disorders in Sphynx and Devon Rex cats. Affected cats displayed a slowly progressive myopathy with clinical and histologic hallmarks of muscular dystrophy including skeletal muscle weakness with no involvement of peripheral nerves or CNS. Skeletal muscles had myopathic features and reduced expression of alpha-dystroglycan, while beta-dystroglycan, sarcoglycans, and dystrophin were expressed at normal levels. In the Sphynx cat, analysis of laminin and lectin binding capacity demonstrated no loss in overall glycosylation or ligand binding for the alpha-dystroglycan protein, only a loss of protein expression. A reduction in laminin-alpha2 expression in the basal lamina surrounding skeletal myofibers was also observed. Sequence analysis of translated regions of the feline dystroglycan gene (DAG1) in affected cats did not identify a causative mutation, and levels of DAG1 mRNA determined by real-time QRT-PCR did not differ significantly from normal controls. Reduction in the levels of glycosylated alpha-dystroglycan by immunoblot was also identified in an affected Devon Rex cat. These data suggest that muscular dystrophy in Sphynx and Devon Rex cats results from a deficiency in alpha-dystroglycan protein expression, and as such may represent a new type of dystroglycanopathy where expression, but not glycosylation, is affected.
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Affiliation(s)
- Paul T Martin
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Department of Pediatrics, Ohio State University, College of Medicine, Columbus, OH 43205, USA
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Thompson O, Kleino I, Crimaldi L, Gimona M, Saksela K, Winder SJ. Dystroglycan, Tks5 and Src mediated assembly of podosomes in myoblasts. PLoS One 2008; 3:e3638. [PMID: 18982058 PMCID: PMC2572840 DOI: 10.1371/journal.pone.0003638] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 10/17/2008] [Indexed: 01/07/2023] Open
Abstract
Background Dystroglycan is a ubiquitously expressed cell adhesion receptor best understood in its role as part of the dystrophin glycoprotein complex of mature skeletal muscle. Less is known of the role of dystroglycan in more fundamental aspects of cell adhesion in other cell types, nor of its role in myoblast cell adhesion. Principal Findings We have examined the role of dystroglycan in the early stages of myoblast adhesion and spreading and found that dystroglycan initially associates with other adhesion proteins in large puncta morphologically similar to podosomes. Using a human SH3 domain phage display library we identified Tks5, a key regulator of podosomes, as interacting with β-dystroglycan. We verified the interaction by immunoprecipitation, GST-pulldown and immunfluorescence localisation. Both proteins localise to puncta during early phases of spreading, but importantly following stimulation with phorbol ester, also localise to structures indistinguishable from podosomes. Dystroglycan overexpression inhibited podosome formation by sequestering Tks5 and Src. Mutation of dystroglycan tyrosine 890, previously identified as a Src substrate, restored podosome formation. Conclusions We propose therefore, that Src-dependent phosphorylation of β-dystroglycan results in the formation of a Src/dystroglycan complex that drives the SH3-mediated association between dystroglycan and Tks5 which together regulate podosome formation in myoblasts.
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Affiliation(s)
- Oliver Thompson
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Iivari Kleino
- Department of Virology, Haartman Institute, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Luca Crimaldi
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Chieti, Italy
| | - Mario Gimona
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, Santa Maria Imbaro, Chieti, Italy
| | - Kalle Saksela
- Department of Virology, Haartman Institute, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Steve J. Winder
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
- * E-mail:
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Petrakis S, Irinopoulou T, Panagiotidis CH, Engelstein R, Lindstrom J, Orr-Urtreger A, Gabizon R, Grigoriadis N, Sklaviadis T. Cellular prion protein co-localizes with nAChR beta4 subunit in brain and gastrointestinal tract. Eur J Neurosci 2008; 27:612-20. [PMID: 18279314 DOI: 10.1111/j.1460-9568.2008.06037.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PrP(C), the cellular isoform of prion protein, is widely expressed in most tissues, including brain, muscle and gastrointestinal tract. Despite its involvement in several bioprocesses, PrP has still no apparent physiological role. During propagation of transmissible spongiform encephalopathies (TSE), prion protein is converted to the pathological isoform, PrP(Sc), in a process believed to be mediated by unknown host factors. The identification of proteins associated with PrP may provide information about both the biology of prions and the pathogenesis of TSE. Thus far, PrP(C) has been shown to interact with synaptic proteins, components of the cytoskeleton and intracellular proteins involved in signalling pathways. Here, we describe the association of PrP with the beta4 subunit of nicotinic acetylcholine receptor (nAChR), as indicated by co-immunoprecipitation assays and double-label immunofluorescence. The interaction between prion protein and native beta4 subunit was further studied by affinity chromatography, using immobilized and refolded recombinant PrP as a bait and brain homogenates from normal individuals. Additionally, the participation of beta4 subunit in the pathogenesis of TSE was studied by in vivo assays. beta4(-/-) and wild-type mice were challenged with the RML (Rocky Mountain Laboratories) infectious agent. Transgenic animals displayed altered incubation times but the deletion of beta4 subunit did not result in a significant change of the incubation period of the disease. Our results suggest that PrP(C) is a member of a multiprotein membrane complex participating in the formation and function of alpha3beta4 nAChR.
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Affiliation(s)
- S Petrakis
- Prion Disease Research Group, Laboratory of Pharmacology, School of Pharmaceutical Sciences, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
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Martin LT, Glass M, Dosunmu E, Martin PT. Altered expression of natively glycosylated alpha dystroglycan in pediatric solid tumors. Hum Pathol 2007; 38:1657-68. [PMID: 17640712 PMCID: PMC2850815 DOI: 10.1016/j.humpath.2007.03.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 11/28/2006] [Accepted: 03/12/2007] [Indexed: 10/23/2022]
Abstract
Altered glycosylation and/or expression of dystroglycan have been reported in forms of congenital muscular dystrophy as well as in cancers of the breast, colon, and oral epithelium. To date, however, there has been no study of the expression of dystroglycan in pediatric solid tumors. Using a combination of immunostaining on tissue microarrays and immunoblotting of snap-frozen unfixed tissues, we demonstrate a significant reduction in native alpha dystroglycan expression in pediatric alveolar rhabdomyosarcoma (RMS), embryonal RMS, neuroblastoma (NBL), and medulloblastoma, whereas expression of beta dystroglycan, which is cotranslated with alpha dystroglycan, is largely unchanged. Loss of native alpha dystroglycan expression was significantly more pronounced in stage 4 NBL than in pooled samples of stage 1 and stage 2 NBL, suggesting that loss of native alpha dystroglycan expression increases with advancing tumor stage. Neuroblastoma and RMS samples with reduced expression of native alpha dystroglycan also showed reduced laminin binding in laminin overlay experiments. Expression of natively glycosylated alpha dystroglycan was not altered in several other pediatric tumor types when compared with appropriate normal tissue controls. These data provide the first evidence that alpha dystroglycan glycosylation and laminin binding to alpha dystroglycan are altered in certain pediatric solid tumors and suggest that aberrant dystroglycan glycosylation may contribute to tumor cell biology in patients with RMS, medulloblastoma, and NBL.
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Affiliation(s)
- Laura T Martin
- Division of Pediatric Hematology/Oncology, Department of Pediatrics, Ohio State University College of Medicine and Public Health, Columbus, OH 43205, USA.
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Lynch GS, Schertzer JD, Ryall JG. Therapeutic approaches for muscle wasting disorders. Pharmacol Ther 2007; 113:461-87. [PMID: 17258813 DOI: 10.1016/j.pharmthera.2006.11.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Revised: 11/10/2006] [Accepted: 11/10/2006] [Indexed: 12/12/2022]
Abstract
Muscle wasting and weakness are common in many disease states and conditions including aging, cancer cachexia, sepsis, denervation, disuse, inactivity, burns, HIV-acquired immunodeficiency syndrome (AIDS), chronic kidney or heart failure, unloading/microgravity, and muscular dystrophies. Although the maintenance of muscle mass is generally regarded as a simple balance between protein synthesis and protein degradation, these mechanisms are not strictly independent, but in fact they are coordinated by a number of different and sometimes complementary signaling pathways. Clearer details are now emerging about these different molecular pathways and the extent to which these pathways contribute to the etiology of various muscle wasting disorders. Therapeutic strategies for attenuating muscle wasting and improving muscle function vary in efficacy. Exercise and nutritional interventions have merit for slowing the rate of muscle atrophy in some muscle wasting conditions, but in most cases they cannot halt or reverse the wasting process. Hormonal and/or other drug strategies that can target key steps in the molecular pathways that regulate protein synthesis and protein degradation are needed. This review describes the signaling pathways that maintain muscle mass and provides an overview of some of the major conditions where muscle wasting and weakness are indicated. The review provides details on some therapeutic strategies that could potentially attenuate muscle atrophy, promote muscle growth, and ultimately improve muscle function. The emphasis is on therapies that can increase muscle mass and improve functional outcomes that will ultimately lead to improvement in the quality of life for affected patients.
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Affiliation(s)
- Gordon S Lynch
- Basic and Clinical Myology Laboratory, Department of Physiology, The University of Melbourne, Victoria 3010, Australia.
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Romo-Yáñez J, Ceja V, Ilarraza-Lomelí R, Coral-Vázquez R, Velázquez F, Mornet D, Rendón A, Montañez C. Dp71ab/DAPs complex composition changes during the differentiation process in PC12 cells. J Cell Biochem 2007; 102:82-97. [PMID: 17390338 DOI: 10.1002/jcb.21281] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PC12 cells express different Dp71 isoforms originated from alternative splicing; one of them, Dp71ab lacks exons 71 and 78. To gain insight into the function of Dp71 isoforms we identified dystrophin associated proteins (DAPs) that associate in vivo with Dp71ab during nerve growth factor (NGF) induced differentiation of PC12 cells. DAPs expression was analyzed by RT-PCR, Western blot and indirect immunofluorescence, showing the presence of each mRNA and protein corresponding to alpha-, beta-, gamma-, delta-, and epsilon-sarcoglycans as well as zeta-sarcoglycan mRNA. Western blot analysis also revealed the expression of beta-dystroglycan, alpha1-syntrophin, alpha1-, and beta-dystrobrevins. We have established that Dp71ab forms a complex with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and alpha-, beta- and gamma-sarcoglycans in undifferentiated PC12 cells. In differentiated PC12 cells, the complex composition changes since Dp71ab associates only with beta-dystroglycan, alpha1-syntrophin, beta-dystrobrevin, and delta-sarcoglycan. Interestingly, neuronal nitric oxide synthase associates with the Dp71ab/DAPs complex during NGF treatment, raising the possibility that Dp71ab may be involved in signal transduction events during neuronal differentiation.
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Affiliation(s)
- J Romo-Yáñez
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Avenida Instituto Politécnico Nacional 2508, Apartado Postal 14-740, C.P. 07000, Ciudad de México, México
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Sgambato A, De Paola B, Migaldi M, Di Salvatore M, Rettino A, Rossi G, Faraglia B, Boninsegna A, Maiorana A, Cittadini A. Dystroglycan expression is reduced during prostate tumorigenesis and is regulated by androgens in prostate cancer cells. J Cell Physiol 2007; 213:528-39. [PMID: 17516554 DOI: 10.1002/jcp.21130] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Prostate cancer, the most frequently diagnosed cancer in Western men, can display a high variability in term of clinical aggressiveness and prognosis and none of the available markers is able to accurately predict its clinical course. Dystroglycan (DG), a non-integrin adhesion molecule, is a complex formed by two subunits, alpha- and beta-DG, which bind to extracellular matrix molecules and cytoskeleton, respectively. DG expression is frequently reduced in human cancers and has been related to tumor grade and aggressiveness. This study investigated the role of DG in human prostate tumorigenesis and its suitability as a prognostic marker. The expression level of extracellular alpha-DG subunit was frequently reduced in human prostate cancer cell lines and primary tumors and the percentage of positive tumor cells was significantly further decreased in vivo following androgen ablation therapy (median = 1%) compared to pre-treatment samples (median = 28%). A significant relationship was observed between alpha-DG staining on the post-treatment samples and tumor recurrence. A dose- and time-dependent decrease of DG expression also occurred in human prostate cancer cells following treatment with the anti-androgen flutamide. Stable expression of an exogenous DG cDNA in the LNCaP human prostate carcinoma cell line resulted in a marked inhibition of both anchorage-dependent and independent growth and of the in vivo tumorigenicity. These findings confirm and extend previous evidence that disturbances in the function of the DG complex might contribute to the definition of the malignant behavior of prostate cancer cells and suggest that androgens might regulate DG expression in these cells.
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Affiliation(s)
- A Sgambato
- Laboratorio di Oncologia Molecolare, Centro di Riferimento Oncologico di Basilicata, Rionero in Vulture (PZ), Italy.
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Bozzi M, Sciandra F, Ferri L, Torreri P, Pavoni E, Petrucci TC, Giardina B, Brancaccio A. Concerted mutation of Phe residues belonging to the ?-dystroglycan ectodomain strongly inhibits the interaction with ?-dystroglycan in�vitro. FEBS J 2006; 273:4929-43. [PMID: 17018058 DOI: 10.1111/j.1742-4658.2006.05492.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The dystroglycan adhesion complex consists of two noncovalently interacting proteins: alpha-dystroglycan, a peripheral extracellular subunit that is extensively glycosylated, and the transmembrane beta-dystroglycan, whose cytosolic tail interacts with dystrophin, thus linking the F-actin cytoskeleton to the extracellular matrix. Dystroglycan is thought to play a crucial role in the stability of the plasmalemma, and forms strong contacts between the extracellular matrix and the cytoskeleton in a wide variety of tissues. Abnormal membrane targeting of dystroglycan subunits and/or their aberrant post-translational modification are often associated with several pathologic conditions, ranging from neuromuscular disorders to carcinomas. A putative functional hotspot of dystroglycan is represented by its intersubunit surface, which is contributed by two amino acid stretches: approximately 30 amino acids of beta-dystroglycan (691-719), and approximately 15 amino acids of alpha-dystroglycan (550-565). Exploiting alanine scanning, we have produced a panel of site-directed mutants of our two consolidated recombinant peptides beta-dystroglycan (654-750), corresponding to the ectodomain of beta-dystroglycan, and alpha-dystroglycan (485-630), spanning the C-terminal domain of alpha-dystroglycan. By solid-phase binding assays and surface plasmon resonance, we have determined the binding affinities of mutated peptides in comparison to those of wild-type alpha-dystroglycan and beta-dystroglycan, and shown the crucial role of two beta-dystroglycan phenylalanines, namely Phe692 and Phe718, for the alpha-beta interaction. Substitution of the alpha-dystroglycan residues Trp551, Phe554 and Asn555 by Ala does not affect the interaction between dystroglycan subunits in vitro. As a preliminary analysis of the possible effects of the aforementioned mutations in vivo, detection through immunofluorescence and western blot of the two dystroglycan subunits was pursued in dystroglycan-transfected 293-Ebna cells.
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Affiliation(s)
- Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy
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Sgambato A, Tarquini E, Resci F, De Paola B, Faraglia B, Camerini A, Rettino A, Migaldi M, Cittadini A, Zannoni GF. Aberrant expression of alpha-dystroglycan in cervical and vulvar cancer. Gynecol Oncol 2006; 103:397-404. [PMID: 16765426 DOI: 10.1016/j.ygyno.2006.03.059] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 03/10/2006] [Accepted: 03/15/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVES Cervical and vulvar cancers develop through well-defined precursor lesions but their exact pathogenesis is still unknown. The dystroglycan complex is a transmembrane glycoprotein that forms a continuous link from the extracellular matrix to the actin cytoskeleton. Deregulated expression of dystroglycan has been reported in human malignancies and related to tumor differentiation and aggressiveness. In this study, expression of dystroglycan was evaluated in the multistep cervical and vulvar tumorigenesis. METHODS Expression of the dystroglycan complex was evaluated by immunostaining in lesions representing different stages of vulvar and cervical tumorigenesis using a monoclonal antibody which recognizes carbohydratic epitopes on the alpha-dystroglycan subunit. RESULTS alpha-dystroglycan was constantly detected in normal cervical epithelium with a mean percentage of positive cells higher than 80%. A progressive significant reduction in the mean percentage of positive cells was observed in low (67%) and high grade SIL (14%) and in invasive carcinomas (2.6%) of the cervix. In cancers, no differences were observed in terms of percentage of positive cells when cases were stratified according with either tumor grade or stage. A progressive significant reduction in the mean percentage of positive cells was also observed from normal vulvar epithelium (90%) to VIN1 (66%), VIN2 (28%) and invasive vulvar carcinomas (22%). No significant decrease in the alpha-dystroglycan staining was observed in squamous cell hyperplasia lesions (85%) while lichen sclerosus displayed a percentage of positive cells (47%) significantly lower than normal epithelium. CONCLUSIONS Detection of alpha-dystroglycan is frequently lost in human cervical and vulvar tumorigenesis and further studies are warranted to verify whether evaluation of this molecule might serve as marker of risk progression of preneoplastic lesions and to better understand its significance in terms of cancer development.
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Affiliation(s)
- Alessandro Sgambato
- Centro di Ricerche Oncologiche Giovanni XXIII-Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, 00168 Rome, Italy.
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Shah WA, Peng H, Carbonetto S. Role of non-raft cholesterol in lymphocytic choriomeningitis virus infection via alpha-dystroglycan. J Gen Virol 2006; 87:673-678. [PMID: 16476990 DOI: 10.1099/vir.0.81444-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dystroglycan (DG) is an extracellular matrix receptor necessary for the development of metazoans from flies to humans and is also an entry route for various pathogens. Lymphocytic choriomeningitis virus (LCMV), a member of the family Arenaviridae, infects by binding to alpha-DG. Here, the role of cholesterol lipid rafts in infection by LCMV via alpha-DG was investigated. The cholesterol-sequestering drugs methyl-beta-cyclodextrin (MbetaCD), filipin and nystatin inhibited the infectivity of LCMV selectively, but did not affect infection by vesicular stomatitis virus. Cholesterol loading after depletion with MbetaCD restored infectivity to control levels. DG was not found in lipid rafts identified with the raft marker ganglioside GM1. Treatment with MbetaCD, however, enhanced the solubility of DG. This may reflect the association of DG with cholesterol outside lipid rafts and suggests that association of DG with non-raft cholesterol is critical for infection by LCMV through alpha-DG.
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Affiliation(s)
- Waris A Shah
- Center for Research in Neuroscience and Department of Neurology and Neurosurgery, McGill University, Montréal General Hospital Research Institute, 1650 Cedar Avenue, Montréal, Québec H3G 1A4, Canada
| | - Huashan Peng
- Center for Research in Neuroscience and Department of Neurology and Neurosurgery, McGill University, Montréal General Hospital Research Institute, 1650 Cedar Avenue, Montréal, Québec H3G 1A4, Canada
| | - Salvatore Carbonetto
- Center for Research in Neuroscience and Department of Neurology and Neurosurgery, McGill University, Montréal General Hospital Research Institute, 1650 Cedar Avenue, Montréal, Québec H3G 1A4, Canada
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Halayko AJ, Stelmack GL. The association of caveolae, actin, and the dystrophin-glycoprotein complex: a role in smooth muscle phenotype and function? Can J Physiol Pharmacol 2006; 83:877-91. [PMID: 16333360 DOI: 10.1139/y05-107] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Smooth muscle cells exhibit phenotypic and mechanical plasticity. During maturation, signalling pathways controlling actin dynamics modulate contractile apparatus-associated gene transcription and contractile apparatus remodelling resulting from length change. Differentiated myocytes accumulate abundant caveolae that evolve from the structural association of lipid rafts with caveolin-1, a protein with domains that confer unique functional properties. Caveolae and caveolin-1 modulate and participate in receptor-mediated signalling, and thus contribute to functional diversity of phenotypically similar myocytes. In mature smooth muscle, caveolae are partitioned into discrete linear domains aligned with structural proteins that tether actin to the extracellular matrix. Caveolin-1 binds with beta-dystroglycan, a subunit of the dystrophin glycoprotein complex (DGC), and with filamin, an actin binding protein that organizes cortical actin, to which integrins and focal adhesion complexes are anchored. The DGC is linked to the actin cytoskeleton by a dystrophin subunit and is a receptor for extracellular laminin. Thus, caveolae and caveolin-associated signalling proteins and receptors are linked via structural proteins to a dynamic filamentous actin network. Despite development of transgenic models to investigate caveolins and membrane-associated actin-linking proteins in skeletal and cardiac muscle function, only superficial understanding of this association in smooth muscle phenotype and function has emerged.
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Affiliation(s)
- Andrew J Halayko
- Department of Physiology, University of Manitoba, Winnipeg, Canada.
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Mendell JR, Boué DR, Martin PT. The congenital muscular dystrophies: recent advances and molecular insights. Pediatr Dev Pathol 2006; 9:427-43. [PMID: 17163796 PMCID: PMC2855646 DOI: 10.2350/06-07-0127.1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2006] [Accepted: 08/30/2006] [Indexed: 01/16/2023]
Abstract
Over the past decade, molecular understanding of the congenital muscular dystrophies (CMDs) has greatly expanded. The diseases can be classified into 3 major groups based on the affected genes and the location of their expressed protein: abnormalities of extracellular matrix proteins (LAMA2, COL6A1, COL6A2, COL6A3), abnormalities of membrane receptors for the extracellular matrix (fukutin, POMGnT1, POMT1, POMT2, FKRP, LARGE, and ITGA7), and abnormal endoplasmic reticulum protein (SEPN1). The diseases begin in the perinatal period or shortly thereafter. A specific diagnosis can be challenging because the muscle pathology is usually not distinctive. Immunostaining of muscle using a battery of antibodies can help define a disorder that will need confirmation by gene testing. In muscle diseases with overlapping pathological features, such as CMD, careful attention to the clinical clues (e.g., family history, central nervous system features) can help guide the battery of immunostains necessary to target an unequivocal diagnosis.
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Affiliation(s)
- Jerry R Mendell
- Department of Pediatrics, Columbus Children's Hospital and Research Institute and The Ohio State University, 700 Children's Drive, Columbus, OH 43205, USA.
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40
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Sgambato A, Di Salvatore MA, De Paola B, Rettino A, Faraglia B, Boninsegna A, Graziani C, Camerini A, Proietti G, Cittadini A. Analysis of dystroglycan regulation and functions in mouse mammary epithelial cells and implications for mammary tumorigenesis. J Cell Physiol 2006; 207:520-9. [PMID: 16447256 DOI: 10.1002/jcp.20600] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Abnormalities in the interactions of cells with the extracellular matrix (ECM) play an important role in the development and progression of many types of cancer and are a hallmark of malignant transformation. The dystroglycan (DG) complex is a transmembrane glycoprotein that forms a continuous link from the ECM to the actin cytoskeleton, providing structural integrity and perhaps transducing signal, in a manner similar to integrins. Deregulated expression of DG has been reported in a variety of human malignancies and related to tumor differentiation and aggressiveness. In breast cancer, reduced DG expression has been associated with patient survival and with loss of differentiation of tumor cells. Limited data are available on DG physiology in epithelial cells. In this study, we used the HC11 spontaneously immortalized murine mammary epithelial cells to study DG function(s) and regulation in normal cells. We found that expression of DG protein and mRNA is cell-cycle and cell-density regulated in these cells. Moreover, expression of both DG subunits increased upon lactogenic differentiation of the HC11 cells. The turnover of cell-surface-expressed DG was evaluated in the same cells and half-life of DG subunits was evaluated to be about 12 h. DG-specific small inhibitory RNAs were used to analyze the effects of a reduced expression of DG in these cells. Cells in which DG expression was suppressed were growth inhibited, accumulated in the S-phase of the cell cycle, failed to undergo lactogenic differentiation, and displayed an increase in the percentage of apoptotic cells. Moreover, changes were observed in the expression and/or activity of several molecules involved in cell growth control. These results demonstrate that DG expression is tightly regulated in normal mammary epithelial cells and support the hypothesis that DG is involved in several functions other than structural integrity in these cells. This finding provides new insight into the roles played by DG in epithelial cell physiology and will contribute to our understanding of its involvement in the process of epithelial cell transformation.
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Affiliation(s)
- A Sgambato
- Centro di Ricerche Oncologiche "Giovanni XXIII", Istituto di Patologia Generale, Catholic University, Rome, Italy.
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Ceccarini M, Torreri P, Lombardi DG, Macchia G, Macioce P, Petrucci TC. Molecular Basis of Dystrobrevin Interaction with Kinesin Heavy Chain: Structural Determinants of their Binding. J Mol Biol 2005; 354:872-82. [PMID: 16288919 DOI: 10.1016/j.jmb.2005.09.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Accepted: 09/22/2005] [Indexed: 11/19/2022]
Abstract
Dystrobrevins are a family of widely expressed dystrophin-associated proteins that comprises alpha and beta isoforms and displays significant sequence homology with several protein-binding domains of the dystrophin C-terminal region. The complex distribution of the multiple dystrobrevin isoforms suggests that the variability of their composition may be important in mediating their function. We have recently identified kinesin as a novel dystrobrevin-interacting protein and localized the dystrobrevin-binding site on the cargo-binding domain of neuronal kinesin heavy chain (Kif5A). In the present study, we assessed the kinetics of the dystrobrevin-Kif5A interaction by quantitative pull-down assay and surface plasmon resonance (SPR) analysis and found that beta-dystrobrevin binds to kinesin with high affinity (K(D) approximately 40 nM). Comparison of the sensorgrams obtained with alpha and beta-dystrobrevin at the same concentration of analyte showed a lower affinity of alpha compared to that of beta-dystrobrevin, despite their functional domain homology and about 70% sequence identity. Analysis of the contribution of single dystrobrevin domains to the interaction revealed that the deletion of either the ZZ domain or the coiled-coil region decreased the kinetics of the interaction, suggesting that the tertiary structure of dystrobrevin may play a role in regulating the interaction of dystrobrevin with kinesin. In order to understand if structural changes induced by post-translational modifications could affect dystrobrevin affinity for kinesin, we phosphorylated beta-dystrobrevin in vitro and found that it showed reduced binding capacity towards kinesin. The interaction between the adaptor/scaffolding protein dystrobrevin and the motor protein kinesin may play a role in the transport and targeting of components of the dystrophin-associated protein complex to specific sites in the cell, with the differences in the binding properties of dystrobrevin isoforms reflecting their functional diversity within the same cell type. Phosphorylation events could have a regulatory role in this context.
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Affiliation(s)
- Marina Ceccarini
- Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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Zhan Y, Tremblay MR, Melian N, Carbonetto S. Evidence that dystroglycan is associated with dynamin and regulates endocytosis. J Biol Chem 2005; 280:18015-24. [PMID: 15728588 DOI: 10.1074/jbc.m409682200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Disruption of the dystroglycan gene in humans and mice leads to muscular dystrophies and nervous system defects including malformation of the brain and defective synaptic transmission. To identify proteins that interact with dystroglycan in the brain we have used immunoaffinity purification followed by mass spectrometry (LC/MS-MS) and found that the GTPase dynamin 1 is a novel dystroglycan-associated protein. The beta-dystroglycan-dynamin 1 complex also included alpha-dystroglycan and Grb2. Overlay assays indicated that dynamin interacts directly with dystroglycan, and immunodepletion showed that only a pool of dynamin is associated with dystroglycan. Dystroglycan was associated and colocalized immunohistochemically with dynamin 1 in the central nervous system in the outer plexiform layer of retina where photoreceptor terminals are found. Endocytosis in neurons is both constitutive, as in non-neural cells, and regulated by neural activity. To assess the function of dystroglycan in the former, we have assayed transferrin uptake in fibroblastic cells differentiated from embryonic stem cells null for both dystroglycan alleles. In wild-type cells, dystroglycan formed a complex with dynamin and codistributed with cortactin at membrane ruffles, which are organelles implicated in endocytosis. Dystroglycan-null cells had a significantly greater transferrin uptake, a process well known to require dynamin. Expression of dystroglycan in null cells by infection with an adenovirus containing dystroglycan reduced transferrin uptake to levels seen in wild-type embryonic stem cells. These data suggest that dystroglycan regulates endocytosis possibly as a result of its interaction with dynamin.
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Affiliation(s)
- Yougen Zhan
- Centre for Research in Neuroscience and the Department of Neurology and Neurosurgery, Montréal General Hospital Research Institute, McGill University, Montréal, Québec H3G 1A4, Canada
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Abstract
Dystroglycan (DG), a non-integrin adhesion molecule, is a pivotal component of the dystrophin-glycoprotein complex, that is expressed in skeletal muscle and in a wide variety of tissues at the interface between the basement membrane (BM) and the cell membrane. DG has been mainly studied for its role in skeletal muscle cell stability and its alterations in muscular diseases, such as dystrophies. However, accumulating evidence have implicated DG in a variety of other biological functions, such as maturation of post-synaptic elements in the central and peripheral nervous system, early morphogenesis, and infective pathogens targeting. Moreover, DG has been reported to play a role in regulating cytoskeletal organization, cell polarization, and cell growth in epithelial cells. Recent studies also indicate that abnormalities in the expression of DG frequently occur in human cancers and may play a role in both the process of tumor progression and in the maintenance of the malignant phenotype. This paper reviews the available information on the biology of DG, the abnormalities found in human cancers, and the implications of these findings with respect to our understanding of cancer pathogenesis and to the development of novel strategies for a better management of cancer patients.
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Affiliation(s)
- Alessandro Sgambato
- Centro di Ricerche Oncologiche Giovanni XXIII, Istituto di Patologia Generale, Catholic University, Rome, Italy.
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Jing J, Lien CF, Sharma S, Rice J, Brennan PA, Górecki DC. Aberrant expression, processing and degradation of dystroglycan in squamous cell carcinomas. Eur J Cancer 2004; 40:2143-51. [PMID: 15341990 DOI: 10.1016/j.ejca.2004.05.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2004] [Accepted: 05/17/2004] [Indexed: 11/27/2022]
Abstract
The alpha- and beta- dystroglycan (DG) proteins are involved in epithelial cell development, formation of the basement membrane and maintenance of tissue integrity. Recently, specific changes in the expression patterns of DGs have been described in some cancers. We studied the expression and localisation of alpha- and beta-DG using Western blotting, immunohistochemistry and reverse transcriptase-polymerase chain reaction analyses in samples of normal oral mucosa, oral squamous cell carcinoma (SCC) and cancer cell lines. The alpha- and beta-DG were localised in the basal layers of normal oral mucosa.However, beta-DG expression in cancer tissues showed evidence of aberrant expression, processing and degradation. alpha-DG was altered in all oral cancer samples and cell lines, despite the persistent presence of DG mRNA in cancer cells. Using matrix metalloproteinase (MMP) inhibitors, we determined that beta-DG degradation in carcinoma cell lines can be mediated by MMPs but this process is highly variable, even in cells from the same cancer type. Considering the multifaceted role of DG in epithelial development, it appears that the role of DG degradation in cancer growth and spread, although currently poorly understood, may be important.
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Affiliation(s)
- Jie Jing
- School of Pharmacy and Biomedical Sciences, Institute of Biomedical and Biomolecular Sciences, Molecular Medicine Group, University of Portsmouth, St. Michael's Building, White Swan Road, PO1 2DT, UK
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Brennan PA, Jing J, Ethunandan M, Górecki D. Dystroglycan complex in cancer. Eur J Surg Oncol 2004; 30:589-92. [PMID: 15256230 DOI: 10.1016/j.ejso.2004.03.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2004] [Indexed: 10/26/2022] Open
Abstract
Abnormalities in the interactions between tumour cells, adhesion molecules and extracellular matrix proteins are often implicated in the behaviour of carcinoma cells. The alpha- and beta-dystroglycan (DG) proteins form part of the large dystrophin-associated protein (DAP) complex. They are involved in epithelial cell development, formation of the basement membrane and maintenance of tissue integrity. Specific changes and reduction or loss of DG expression have been reported in human breast, colon, head and neck, and prostate cancers, implicating it in tumour invasion and dissemination. Degradation of beta-DG by matrix metalloproteinase (MMP) enzymes may assist tumour dissemination. We report the present knowledge of the DG interactions in solid tumour biology.
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Affiliation(s)
- P A Brennan
- Maxillofacial Unit, Department of Head and Neck Surgery, Queen Alexandra Hospital, Portsmouth PO6 3LY, UK.
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Qu Q, Smith FI. Alpha-dystroglycan interactions affect cerebellar granule neuron migration. J Neurosci Res 2004; 76:771-82. [PMID: 15160389 DOI: 10.1002/jnr.20129] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The interaction of alpha-dystroglycan (a-DG) with its extracellular binding partners requires glycans attached to its mucin core domain, and defects in the glycosylation of a-DG are associated with both muscular dystrophy and neuronal migration defects. The involvement of a-DG and one of its ligands, agrin, in cerebellar neuronal migration was investigated. Antibodies directed against glycosylated a-DG inhibited granule neuron migration in cerebellar slice cultures. a-DG interactions did not appear to influence neurite outgrowth in cerebellar explant cultures, but enhanced granule neuron binding was observed on cells transfected with a-DG. These results suggest that interactions involving a-DG influence the strength of attachment of granule neurons to the a-DG-expressing Bergmann glial cells that guide granule neuron migration in the cerebellum. Experiments using anti-agrin antibodies suggest that agrin is not involved in these interactions.
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Affiliation(s)
- Qiang Qu
- Shriver Center for Mental Retardation, Waltham, Massachusetts 02452, USA
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Spence HJ, Dhillon AS, James M, Winder SJ. Dystroglycan, a scaffold for the ERK-MAP kinase cascade. EMBO Rep 2004; 5:484-9. [PMID: 15071496 PMCID: PMC1299052 DOI: 10.1038/sj.embor.7400140] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2003] [Revised: 03/01/2004] [Accepted: 03/02/2004] [Indexed: 11/09/2022] Open
Abstract
Dystroglycan is an important cell adhesion receptor linking the actin cytoskeleton, via utrophin and dystrophin, to laminin in the extracellular matrix. To identify adhesion-related signalling molecules associated with dystroglycan, we conducted a yeast two-hybrid screen and identified mitogen-activated protein (MAP) kinase kinase 2 (MEK2) as a beta-dystroglycan interactor. Pull-down experiments and localization studies substantiated a physiological link between beta-dystroglycan and MEK and localized MEK with dystroglycan in membrane ruffles. Moreover, we also identified active extracellular signal-regulated kinase (ERK), the downstream kinase from MEK, as another interacting partner for beta-dystroglycan and localized both active ERK and dystroglycan to focal adhesions in fibroblast cells. These studies suggest a role for dystroglycan as a multifunctional adaptor or scaffold capable of interacting with components of the ERK-MAP kinase cascade including MEK and ERK. These findings have important implications for our understanding of the role of dystroglycan in normal cellular processes and in disease states such as muscular dystrophy.
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Affiliation(s)
- Heather J Spence
- The Beatson Institute for Cancer Research, CRUK Beatson Laboratories, Switchback Road, Glasgow G61 1BD, UK
| | - Amardeep S Dhillon
- The Beatson Institute for Cancer Research, CRUK Beatson Laboratories, Switchback Road, Glasgow G61 1BD, UK
| | - Marian James
- Centre for Developmental Genetics, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
- Present address: Ascent Technology Ltd, Leicester LE19 1SX, UK
| | - Steven J Winder
- Centre for Developmental Genetics, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
- Tel: +44 114 222 2332; Fax: +44 114 276 5413; E-mail:
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García-Tovar CG, Luna J, Mena R, Soto-Zárate CI, Cortés R, Pérez A, León-Avila G, Mornet D, Rendón A, Hernández JM. Dystrophin isoform Dp7l is present in lamellipodia and focal complexes in human astrocytoma cells U-373 MG. Acta Histochem 2003; 104:245-54. [PMID: 12389738 DOI: 10.1078/0065-1281-00654] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Dp71 is the most abundant product of the dmd gene in the brain. There are at least 2 isoforms derived from alternative splicing of exon 78 (Dp71d, which contains exon 78 and Dp71f, the spliced isoform) but the precise localization and function of each isoform is still unknown. In the present study, we demonstrate by RT-PCR that the Dp71f isoform is present in an astrocytoma cell line U-373 MG, and its subcellular localization was determined in the cytoplasm, particularly in perinuclear areas, with lower amounts towards the periphery but increasing in the leader borders of lamellipodia and focal complexes. Double labeling indirect immunofluorescence showed that Dp71f colocalized with actin-like beta-dystroglycan and beta-1 integrin. We also demonstrated by triple labeling that Dp71f was colocalized with actin and two members of integrin complexes, alpha-actinin and vinculin, in focal complexes. Ventral plasma membranes were enriched and in those containing focal complex proteins, we found colocalization of Dp71f, actin and vinculin. It is concluded that U-373 MG cells express Dp71f as part of lamellipodia and focal complex proteins, and possibly connected via distroglycan complexes to integrin complexes.
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Facchiano A, Russo K, Facchiano AM, De Marchis F, Facchiano F, Ribatti D, Aguzzi MS, Capogrossi MC. Identification of a novel domain of fibroblast growth factor 2 controlling its angiogenic properties. J Biol Chem 2003; 278:8751-60. [PMID: 12496262 DOI: 10.1074/jbc.m209936200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor 2 (FGF-2) is a potent factor modulating the activity of many cell types. Its dimerization and binding to high affinity receptors are considered to be necessary steps to induce FGF receptor phosphorylation and signaling activation. A structural analysis was carried out and a region encompassing residues 48-58 of human FGF-2 was identified, as potentially involved in FGF-2 dimerization. A peptide (FREG-48-58) derived from this region strongly and specifically inhibited FGF-2 induced proliferation and migration of primary bovine aorta endothelial cells (BAEC) in vitro, and markedly reduced FGF-2-dependent angiogenesis in two distinct in vivo assays. To further investigate the role of region 48-58, a polyclonal antibody raised against FREG-(48-58) was tested and was found to block FGF-2 action in vitro. Human FGF-2 has three histidine residues, one falling within the region 48-58. Chemical modification of histidine residues blocked FGF-2 activity and FREG-(48-58) inhibitory effect in vitro, indicating that histidine residues, in particular the one within FREG-(48-58) region, play a crucial role in the observed activity. Additional experiments showed that FREG-(48-58) specifically interacted with FGF-2, impaired FGF-2-interaction with itself, with heparin and with FGF receptor 1, and inhibited FGF-2-induced receptor phosphorylation and FGF-2 internalization. These data indicate for the first time that region 48-58 of FGF-2 is a functional domain controlling FGF-2 activity.
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Affiliation(s)
- Antonio Facchiano
- Laboratorio Patologia Vascolare, Istituto Dermopatico dell'Immacolata, IRCCS, 00167 Roma, Italy.
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Sgambato A, Migaldi M, Montanari M, Camerini A, Brancaccio A, Rossi G, Cangiano R, Losasso C, Capelli G, Trentini GP, Cittadini A. Dystroglycan expression is frequently reduced in human breast and colon cancers and is associated with tumor progression. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 162:849-60. [PMID: 12598319 PMCID: PMC1868099 DOI: 10.1016/s0002-9440(10)63881-3] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Dystroglycan (DG) is an adhesion molecule responsible for crucial interactions between extracellular matrix and cytoplasmic compartment. It is formed by two subunits, alpha-DG (extracellular) and beta-DG (transmembrane), that bind to laminin in the matrix and dystrophin in the cytoskeleton, respectively. In this study we evaluated by Western blot analysis the expression of DG in a series of human cancer cell lines of various histogenetic origin and in a series of human primary colon and breast cancers. Decreased expression of DG was observed in most of the cell lines and in both types of tumors and correlated with higher tumor grade and stage. Analysis of the mRNA levels suggested that expression of DG protein is likely regulated at a posttranscriptional level. Evaluation of alpha-DG expression by immunostaining in a series of archival cases of primary breast carcinomas confirmed that alpha-DG expression is lost in a significant fraction of tumors (66%). Loss of DG staining correlated with higher tumor stage (P = 0.022), positivity for p53 (P = 0.033), and high proliferation index (P = 0.045). A significant correlation was also observed between loss of alpha-DG and overall survival (P = 0.013 by log-rank test) in an univariate analysis. These data indicate that DG expression is frequently lost in human malignancies and suggest that this glycoprotein might play an important role in human tumor development and progression.
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Affiliation(s)
- Alessandro Sgambato
- Centro di Ricerche Oncologiche Giovanni XXIII, Istituto di Patologia Generale, Catholic University, Rome, Italy.
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