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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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Sciandra F, Bottoni P, De Leo M, Braca A, Brancaccio A, Bozzi M. Verbascoside Elicits Its Beneficial Effects by Enhancing Mitochondrial Spare Respiratory Capacity and the Nrf2/HO-1 Mediated Antioxidant System in a Murine Skeletal Muscle Cell Line. Int J Mol Sci 2023; 24:15276. [PMID: 37894956 PMCID: PMC10607197 DOI: 10.3390/ijms242015276] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/11/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Muscle weakness and muscle loss characterize many physio-pathological conditions, including sarcopenia and many forms of muscular dystrophy, which are often also associated with mitochondrial dysfunction. Verbascoside, a phenylethanoid glycoside of plant origin, also named acteoside, has shown strong antioxidant and anti-fatigue activity in different animal models, but the molecular mechanisms underlying these effects are not completely understood. This study aimed to investigate the influence of verbascoside on mitochondrial function and its protective role against H2O2-induced oxidative damage in murine C2C12 myoblasts and myotubes pre-treated with verbascoside for 24 h and exposed to H2O2. We examined the effects of verbascoside on cell viability, intracellular reactive oxygen species (ROS) production and mitochondrial function through high-resolution respirometry. Moreover, we verified whether verbascoside was able to stimulate nuclear factor erythroid 2-related factor (Nrf2) activity through Western blotting and confocal fluorescence microscopy, and to modulate the transcription of its target genes, such as heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), by Real Time PCR. We found that verbascoside (1) improved mitochondrial function by increasing mitochondrial spare respiratory capacity; (2) mitigated the decrease in cell viability induced by H2O2 and reduced ROS levels; (3) promoted the phosphorylation of Nrf2 and its nuclear translocation; (4) increased the transcription levels of HO-1 and, in myoblasts but not in myotubes, those of PGC-1α. These findings contribute to explaining verbascoside's ability to relieve muscular fatigue and could have positive repercussions for the development of therapies aimed at counteracting muscle weakness and mitochondrial dysfunction.
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Affiliation(s)
- Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—SCITEC Sede di Roma, Largo F. Vito, 00168 Roma, Italy
| | - Patrizia Bottoni
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica, Università Cattolica del Sacro Cuore di Roma, Largo F. Vito 1, 00168 Roma, Italy
| | - Marinella De Leo
- Dipartimento di Farmacia, Università di Pisa, Via Bonanno 33, 56126 Pisa, Italy
| | - Alessandra Braca
- Dipartimento di Farmacia, Università di Pisa, Via Bonanno 33, 56126 Pisa, Italy
| | - Andrea Brancaccio
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—SCITEC Sede di Roma, Largo F. Vito, 00168 Roma, Italy
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Manuela Bozzi
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”—SCITEC Sede di Roma, Largo F. Vito, 00168 Roma, Italy
- Dipartimento di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica, Università Cattolica del Sacro Cuore di Roma, Largo F. Vito 1, 00168 Roma, Italy
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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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Wu WJ, Sun SZ, Li BG. Congenital muscular dystrophy caused by beta1,3-N-acetylgalactosaminyltransferase 2 gene mutation: Two case reports. World J Clin Cases 2022; 10:1056-1066. [PMID: 35127920 PMCID: PMC8790464 DOI: 10.12998/wjcc.v10.i3.1056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/20/2021] [Accepted: 12/23/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Mutations in the beta1,3-N-acetylgalactosaminyltransferase 2 (B3GALNT2) gene can lead to impaired glycosylation of α-dystroglycan, which, in turn, causes congenital muscular dystrophy (CMD). The clinical phenotypes of CMD are broad, and there are only a few reports of CMD worldwide.
CASE SUMMARY This report describes the cases of two children with CMD caused by B3GALNT2 gene mutation. The main manifestations of the two cases were abnormal walking posture, language development delay, and abnormal development of the white matter. Case 2 also had unreported symptoms of meningocele and giant arachnoid cyst. Both cases had compound heterozygous mutations of the B3GALNT2 gene, each containing a truncated mutation and a missense mutation, and three of the four loci had not been reported. Nineteen patients with CMD caused by B3GALNT2 gene mutation were found in the literature. Summary and analysis of the characteristics of CMD caused by B3GALNT2 gene mutation showed that 100% of the cases had nervous system involvement. Head magnetic resonance imaging often showed abnormal manifestations, and more than half of the children had eye and muscle involvement; some of the gene-related symptoms were self-healing.
CONCLUSION B3GALNT2 gene can be used as one of the candidate genes for screening CMD, cognitive development retardation, epilepsy, and multiple brain developmental malformations in infants.
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Affiliation(s)
- Wen-Juan Wu
- Department of Neurology, Hebei Children's Hospital, Hebei Children's Hospital Affiliated to Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
| | - Su-Zhen Sun
- Department of Neurology, Hebei Children's Hospital, Hebei Children's Hospital Affiliated to Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
| | - Bao-Guang Li
- Department of Neurology, Hebei Children's Hospital, Hebei Children's Hospital Affiliated to Hebei Medical University, Shijiazhuang 050031, Hebei Province, China
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Abstract
Morphological transitions are typically attributed to the actions of proteins and lipids. Largely overlooked in membrane shape regulation is the glycocalyx, a pericellular membrane coat that resides on all cells in the human body. Comprised of complex sugar polymers known as glycans as well as glycosylated lipids and proteins, the glycocalyx is ideally positioned to impart forces on the plasma membrane. Large, unstructured polysaccharides and glycoproteins in the glycocalyx can generate crowding pressures strong enough to induce membrane curvature. Stress may also originate from glycan chains that convey curvature preference on asymmetrically distributed lipids, which are exploited by binding factors and infectious agents to induce morphological changes. Through such forces, the glycocalyx can have profound effects on the biogenesis of functional cell surface structures as well as the secretion of extracellular vesicles. In this review, we discuss recent evidence and examples of these mechanisms in normal health and disease.
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Affiliation(s)
- Joe Chin-Hun Kuo
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA; ,
| | - Matthew J Paszek
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA; , .,Field of Biomedical Engineering and Field of Biophysics, Cornell University, Ithaca, New York 14853, USA.,Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853, USA
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7
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Cloutier G, Sallenbach-Morrissette A, Beaulieu JF. Non-integrin laminin receptors in epithelia. Tissue Cell 2019; 56:71-78. [DOI: 10.1016/j.tice.2018.12.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/17/2018] [Accepted: 12/21/2018] [Indexed: 12/14/2022]
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Nickolls AR, Bönnemann CG. The roles of dystroglycan in the nervous system: insights from animal models of muscular dystrophy. Dis Model Mech 2018; 11:11/12/dmm035931. [PMID: 30578246 PMCID: PMC6307911 DOI: 10.1242/dmm.035931] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dystroglycan is a cell membrane protein that binds to the extracellular matrix in a variety of mammalian tissues. The α-subunit of dystroglycan (αDG) is heavily glycosylated, including a special O-mannosyl glycoepitope, relying upon this unique glycosylation to bind its matrix ligands. A distinct group of muscular dystrophies results from specific hypoglycosylation of αDG, and they are frequently associated with central nervous system involvement, ranging from profound brain malformation to intellectual disability without evident morphological defects. There is an expanding literature addressing the function of αDG in the nervous system, with recent reports demonstrating important roles in brain development and in the maintenance of neuronal synapses. Much of these data are derived from an increasingly rich array of experimental animal models. This Review aims to synthesize the information from such diverse models, formulating an up-to-date understanding about the various functions of αDG in neurons and glia of the central and peripheral nervous systems. Where possible, we integrate these data with our knowledge of the human disorders to promote translation from basic mechanistic findings to clinical therapies that take the neural phenotypes into account. Summary: Dystroglycan is a ubiquitous matrix receptor linked to brain and muscle disease. Unraveling the functions of this protein will inform basic and translational research on neural development and muscular dystrophies.
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Affiliation(s)
- Alec R Nickolls
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Del Favero G, Woelflingseder L, Janker L, Neuditschko B, Seriani S, Gallina P, Sbaizero O, Gerner C, Marko D. Deoxynivalenol induces structural alterations in epidermoid carcinoma cells A431 and impairs the response to biomechanical stimulation. Sci Rep 2018; 8:11351. [PMID: 30054545 PMCID: PMC6063857 DOI: 10.1038/s41598-018-29728-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 07/12/2018] [Indexed: 12/12/2022] Open
Abstract
Morphology together with the capability to respond to surrounding stimuli are key elements governing the spatial interaction of living cells with the environment. In this respect, biomechanical stimulation can trigger significant physiological cascades that can potentially modulate toxicity. Deoxynivalenol (DON, vomitoxin) is one of the most prevalent mycotoxins produced by Fusarium spp. and it was used to explore the delicate interaction between biomechanical stimulation and cytotoxicity in A431 cells. In fact, in addition of being a food contaminant, DON is a relevant toxin for several organ systems. The combination between biomechanical stimulation and the mycotoxin revealed how DON can impair crucial functions affecting cellular morphology, tubulin and lysosomes at concentrations even below those known to be cytotoxic in routine toxicity studies. Sub-toxic concentrations of DON (0.1-1 μM) impaired the capability of A431 cells to respond to a biomechanical stimulation that normally sustains trophic effects in these cells. Moreover, the effects of DON (0.1-10 μM) were partially modulated by the application of uniaxial stretching (0.5 Hz, 24 h, 15% deformation). Ultimately, proteomic analysis revealed the potential of DON to alter several proteins necessary for cell adhesion and cytoskeletal modulation suggesting a molecular link between biomechanics and the cytotoxic potential of the mycotoxin.
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Affiliation(s)
- Giorgia Del Favero
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria.
| | - Lydia Woelflingseder
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Lukas Janker
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Benjamin Neuditschko
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Stefano Seriani
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
- Robotik und Mechatronik Zentrum, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen, Germany
| | - Paolo Gallina
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
| | - Orfeo Sbaizero
- Department of Engineering and Architecture, University of Trieste Via A, Valerio 10, 34127, Trieste, Italy
| | - Christopher Gerner
- Department of Analytical Chemistry, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Währingerstr. 38-40, 1090, Vienna, Austria
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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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11
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Covaceuszach S, Bozzi M, Bigotti MG, Sciandra F, Konarev PV, Brancaccio A, Cassetta A. The effect of the pathological V72I, D109N and T190M missense mutations on the molecular structure of α-dystroglycan. PLoS One 2017; 12:e0186110. [PMID: 29036200 PMCID: PMC5643065 DOI: 10.1371/journal.pone.0186110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 09/25/2017] [Indexed: 11/18/2022] Open
Abstract
Dystroglycan (DG) is a highly glycosylated protein complex that links the cytoskeleton with the extracellular matrix, mediating fundamental physiological functions such as mechanical stability of tissues, matrix organization and cell polarity. A crucial role in the glycosylation of the DG α subunit is played by its own N-terminal region that is required by the glycosyltransferase LARGE. Alteration in this O-glycosylation deeply impairs the high affinity binding to other extracellular matrix proteins such as laminins. Recently, three missense mutations in the gene encoding DG, mapped in the α-DG N-terminal region, were found to be responsible for hypoglycosylated states, causing congenital diseases of different severity referred as primary dystroglycanopaties.To gain insight on the molecular basis of these disorders, we investigated the crystallographic and solution structures of these pathological point mutants, namely V72I, D109N and T190M. Small Angle X-ray Scattering analysis reveals that these mutations affect the structures in solution, altering the distribution between compact and more elongated conformations. These results, supported by biochemical and biophysical assays, point to an altered structural flexibility of the mutant α-DG N-terminal region that may have repercussions on its interaction with LARGE and/or other DG-modifying enzymes, eventually reducing their catalytic efficiency.
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Affiliation(s)
| | - Manuela Bozzi
- Istituto di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore, Roma, Italy
- Istituto di Chimica del Riconoscimento Molecolare—CNR c/o Università Cattolica del Sacro Cuore, Roma, Italy
| | | | - Francesca Sciandra
- Istituto di Chimica del Riconoscimento Molecolare—CNR c/o Università Cattolica del Sacro Cuore, Roma, Italy
| | - Petr V. Konarev
- A.V. Shubnikov Institute of Crystallography of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Moscow, Russia
- National Research Centre “Kurchatov Institute”, Moscow, Russia
| | - Andrea Brancaccio
- Istituto di Chimica del Riconoscimento Molecolare—CNR c/o Università Cattolica del Sacro Cuore, Roma, Italy
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Alberto Cassetta
- Istituto di Cristallografia–CNR, Trieste Outstation, Trieste, Italy
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