11 results on '"Lionel Fontao"'
Search Results
2. Facial skin infection with Ochroconis mirabilis
- Author
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Béatrice Ninet-Bescher, Lionel Fontao, and Raphaël André
- Subjects
ddc:616 ,Adult ,Male ,medicine.medical_specialty ,Skin / pathology ,Administration, Topical ,Microbial Sensitivity Tests ,Biology ,Skin / microbiology ,Dermatology ,Ascomycota / pathogenicity ,Skin / drug effects ,Antifungal Agents / pharmacology ,Ochroconis mirabilis ,Facial skin ,Ascomycota / drug effects ,Treatment Outcome ,Infectious Diseases ,Antifungal Agents / therapeutic use ,Face / microbiology ,Mycoses / microbiology ,medicine ,Humans ,Ascomycota / isolation & purification ,Switzerland - Published
- 2021
3. BPAG1 isoform-b: Complex distribution pattern in striated and heart muscle and association with plectin and α-actinin
- Author
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Yann Schneider, Georgine Faulkner, Marie-France Steiner-Champliaud, Gerhard Wiche, Lionel Fontao, Patryk Konieczny, Marianne Raith, Luca Borradori, Bertrand Favre, Ronald K.H. Liem, Silke Praetzel-Wunder, Adijat Adebola, Lutz Langbein, Frédérique Paulhe, and Arnoud Sonnenberg
- Subjects
Cell Extracts ,Repetitive Sequences, Amino Acid ,Gene isoform ,Protein family ,Dystonin ,Nerve Tissue Proteins ,macromolecular substances ,Biology ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Intermediate Filament Proteins ,Animals ,Humans ,Protein Isoforms ,Myocyte ,Actinin ,Muscle, Skeletal ,Cells, Cultured ,030304 developmental biology ,Mice, Knockout ,0303 health sciences ,Plakin ,Immune Sera ,Myocardium ,Cell Biology ,Plectin ,Molecular biology ,Rats ,Transport protein ,Cytoskeletal Proteins ,Protein Transport ,Desmin ,Carrier Proteins ,030217 neurology & neurosurgery ,Protein Binding - Abstract
BPAG1-b is the major muscle-specific isoform encoded by the dystonin gene, which expresses various protein isoforms belonging to the plakin protein family with complex, tissue-specific expression profiles. Recent observations in mice with either engineered or spontaneous mutations in the dystonin gene indicate that BPAG1-b serves as a cytolinker important for the establishment and maintenance of the cytoarchitecture and integrity of striated muscle. Here, we studied in detail its distribution in skeletal and cardiac muscles and assessed potential binding partners. BPAG1-b was detectable in vitro and in vivo as a high molecular mass protein in striated and heart muscle cells, co-localizing with the sarcomeric Z-disc protein alpha-actinin-2 and partially with the cytolinker plectin as well as with the intermediate filament protein desmin. Ultrastructurally, like alpha-actinin-2, BPAG1-b was predominantly localized at the Z-discs, adjacent to desmin-containing structures. BPAG1-b was able to form complexes with both plectin and alpha-actinin-2, and its NH(2)-terminus, which contains an actin-binding domain, directly interacted with that of plectin and alpha-actinin. Moreover, the protein level of BPAG1-b was reduced in muscle tissues from plectin-null mutant mice versus wild-type mice. These studies provide new insights into the role of BPAG1-b in the cytoskeletal organization of striated muscle.
- Published
- 2010
4. 191 Characterization of the interaction of desmoplakin with keratins and desmin: Implication for genetic cardio-cutaneous syndromes
- Author
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Luca Borradori, Lionel Fontao, Bertrand Favre, and Nadja Begré
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chemistry.chemical_classification ,Pathology ,medicine.medical_specialty ,biology ,Desmoplakin ,Cell Biology ,Dermatology ,Biochemistry ,chemistry ,Keratin ,biology.protein ,medicine ,Desmin ,Molecular Biology - Published
- 2017
5. Molecular Consequences of Deletion of the Cytoplasmic Domain of Bullous Pemphigoid 180 in a Patient with Predominant Features of Epidermolysis Bullosa Simplex
- Author
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Luca Borradori, Daniel Hohl, Kaisa Tasanen, Arnoud Sonnenberg, Jan Koster, Lionel Fontao, Marcel Huber, Leena Bruckner-Tuderman, Oncogenomics, CCA - Cancer biology and immunology, and AII - Cancer immunology
- Subjects
Keratinocytes ,Cytoplasm ,Pathology ,medicine.medical_specialty ,Dystonin ,BP180 ,Nerve Tissue Proteins ,Dermatology ,Biology ,Gene mutation ,Transfection ,Junctional epidermolysis bullosa (medicine) ,Autoantigens ,Biochemistry ,030207 dermatology & venereal diseases ,03 medical and health sciences ,Epidermolysis bullosa simplex ,0302 clinical medicine ,medicine ,Animals ,Humans ,hemidesmosome ,epidermolysis bullosa ,Microscopy, Immunoelectron ,Intermediate filament ,Molecular Biology ,collagen XVII ,030304 developmental biology ,0303 health sciences ,Hemidesmosome ,Integrin beta4 ,Cell Biology ,Plectin ,Hemidesmosomes ,Non-Fibrillar Collagens ,mutations ,medicine.disease ,Protein Structure, Tertiary ,Cell biology ,Cytoskeletal Proteins ,Epidermolysis Bullosa Simplex ,COS Cells ,Epidermolysis bullosa ,Bullous pemphigoid ,Carrier Proteins ,Protein Processing, Post-Translational ,Gene Deletion ,Protein Binding - Abstract
Bullous pemphigoid antigen 2 (BP180; COL17A1) collagen gene mutations typically result in nonlethal junctional epidermolysis bullosa. We have identified a patient, who had phenotypic features of mainly epidermolysis bullosa simplex and evidence for both intraepidermal and junctional blister formation. Mutation analysis disclosed compound heterozygous mutations in the COL17A1 gene, leading to deletion of Ile-18 to Asn-407 from the intracellular domain of BP180, BP180 Delta 18-407. To gain insight into the mechanisms underlying the phenotype, we have investigated the functional consequences of this truncation in BP180. The results demonstrate that: (1) in cultured keratinocytes of the patient, the assembly of hemidesmosomes, and their linkage with intermediate filaments are impaired; (2) BP180 Delta 18-407 is not capable of binding to the hemidesmosomal components BP230, plectin, and the beta 4 subunit of the alpha 6 beta 4 integrin in yeast two-hybrid assays; (3) BP180 Delta 18-407 is recruited into hemidesmosome-like structures in both normal and BP180-deficient transfected keratinocytes when ectopically expressed, suggesting that the extracellular domain of BP180 Delta 18-407 determines its topogenic fate; and, finally (4) the proteolytic shedding of the extracellular domain of BP180 Delta 18-407 is not impaired in transfected COS-7 cells. Collectively, the data demonstrate that the truncation of the intracellular domain of BP180 impairs the organization of hemidesmosomes, affecting both the mechanical stability of basal keratinocytes and dermoepidermal cohesion.
- Published
- 2004
6. Biochemical evidence for interaction between smoothelin and filamentous actin
- Author
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Christine Chaponnier, Guillaume J.J.M. van Eys, Birgit E.J. Teunissen, Lionel Fontao, Sander S. Rensen, Sophie Clément, Giulio Gabbiani, and Petra Niessen
- Subjects
Cytoskeletal Proteins/chemistry/genetics/ metabolism ,Actins/ metabolism ,Swine ,Recombinant Fusion Proteins ,Calponin ,Muscle Proteins ,Arp2/3 complex ,Protein Isoforms/chemistry/genetics/ metabolism ,Enzyme-Linked Immunosorbent Assay ,Rats/ embryology ,macromolecular substances ,ddc:616.07 ,Transfection ,Calponin homology domain ,Filamentous actin ,Cell Line ,Calcium-Binding Proteins/metabolism ,Stress Fibers/metabolism ,Stress Fibers ,Escherichia coli ,Animals ,Protein Isoforms ,Actin-binding protein ,Aorta ,Glutathione Transferase ,biology ,Calcium-Binding Proteins ,Microfilament Proteins ,Actin remodeling ,Cell Biology ,Fibroblasts ,Fibroblasts/cytology/ metabolism ,Aorta/chemistry ,Precipitin Tests ,Actins ,Protein Structure, Tertiary ,Rats ,Cell biology ,Escherichia coli/genetics ,Cytoskeletal Proteins ,biology.protein ,Smoothelin ,Glutathione Transferase/metabolism ,Recombinant Fusion Proteins/metabolism ,MDia1 - Abstract
The two major isoforms of smoothelin (A and B) contain a calponin homology (CH) domain, colocalize with alpha-smooth muscle actin (alpha-SMA) in stress fibers and are only expressed in contractile smooth muscle cells (SMCs). Based on these findings, we hypothesized that smoothelins are involved in smooth muscle cell contraction, presumably via interaction with actin. The interaction between smoothelins and three different actin isoforms (alpha- and gamma-smooth muscle and alpha-skeletal actin [alpha-SKA]) was investigated using several in vitro assays. Smoothelin-B co-immunoprecipitated with alpha-smooth muscle actin from pig aorta extracts. In rat embryonic fibroblasts, transfected smoothelins-A and -B associated with stress fibers. In vitro dot blot assays, in which immobilized actin was overlaid with radio-labeled smoothelin, showed binding of smoothelin-A to actin filaments, but not to monomeric G-actin. A truncated smoothelin, containing the calponin homology domain, associated with stress fibers when transfected and bound to actin filaments in overlay, but to a lesser extent. ELISA results showed that the binding of smoothelin to actin has no significant isoform specificity. Our results indicate an interaction between smoothelin and actin filaments. Moreover, the calponin homology domain and its surrounding sequences appear to be sufficient to accomplish this interaction, although the presence of other domains is apparently necessary to facilitate and/or strengthen the binding to actin.
- Published
- 2004
7. Comparative study of PCR, microscopic examination and culture-based methods for detection and identification of fungi in onychomycosis
- Author
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Lionel Fontao and K. Da Cunha
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Itraconazole ,Biology ,Amplicon ,DNA extraction ,Microbiology ,law.invention ,Infectious Diseases ,medicine.anatomical_structure ,law ,medicine ,Nail (anatomy) ,Terbinafine ,Identification (biology) ,Fluconazole ,Polymerase chain reaction ,medicine.drug - Abstract
This work was supported by a grant from the Swiss Government Excellence Scholarships for Foreign Students to da Cunha KC. Onychomycosis is the most common disease of the nails and represents about a half of all nail abnormalities worldwide. It affects, in particular, males, the elderly, diabetics, and immune-compromised individuals, with toenails being affected to a greater extent than fingernails. The diagnosis of onychomycosis cannot be done only based on clinical presentation, due to the similarity with other onychopathies. Traditionally, fungi identification is based on direct microscopic examination of clinical samples as well as microscopic and macroscopic examination of cultures, and when needed in metabolism tests. However, it is time-consuming, laborious, costly, and requires a certain level of morphological and taxonomical expertise. Furthermore, in the case of onychomycosis the culture sensitivity is only about 50%. Moreover, the identification of cultured isolates is sometime challenging especially when strains do not produce typical characteristics or when Non Dermatophytes Molds (NDM) are the causative agent. With the growing number of organisms recognized as possible fungal pathogens in nails, it is becoming important to ensure the accurate identification of the causative organism. This will help clinicians in selecting the most appropriate therapy. Indeed antifungal agents, such as terbinafine, itraconazole, and fluconazole have a broad spectrum with activity against fungi but some NDM may be poorly responsive or unresponsive to systemic treatments. We have introduced the identification based on DNA extraction directly from human nail samples. We use PCR amplification of DNA coding nuclear ribosomal internal transcribed spacer (ITS). The clinical specimen consisted of 80 nails samples with 60 being positives under microscope using blankophor and 20 were negative. As expected PCR allows detection of fungi in all nail specimen that were positive by microscopy and culture. Moreover, PCR also allows detection of fungal DNA in nails with negative culture but with positive microscopy. In some samples, PCR lead to the amplification of more than one amplicon, which suggests mixed infection. Sequencing of purified amplicons permitted identification of the implicated fungi in the vast majority of case. The results of the present study indicated that PCR is highly advantageous as a diagnostic tool for detection and identification of fungi on direct application to nail specimens. Because during the last decade, cost for DNA sequencing have been dramatically reduced and given the poor sensitivity of culture in onychomycosis, it is becoming reasonable to use PCR/sequencing as a first line method for the diagnosis of onychomycosis. This will provide a quick identification of the implicated fungi and will help clinicians in making rational and effective therapeutic decisions. This will be a direct benefit to patients with dermatophytosis.
- Published
- 2016
8. Production of the bullous pemphigoid antigen 230 (BP230) by Saccharomyces cerevisiae and Pichia pastoris
- Author
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Michel Monod, Lionel Fontao, Bertrand Favre, Jan Koster, Jean-Hilaire Saurat, Emmanuel Laffitte, Luca Borradori, Reza Shafaatian, Oncogenomics, CCA - Cancer biology and immunology, and AII - Cancer immunology
- Subjects
Keratinocytes ,Antigens, Fungal ,Dystonin ,Immunoblotting ,Saccharomyces cerevisiae ,Nerve Tissue Proteins ,Autoantigens ,Pichia ,Pichia pastoris ,law.invention ,law ,Complementary DNA ,Pemphigoid, Bullous ,medicine ,Humans ,Cells, Cultured ,Cloning ,chemistry.chemical_classification ,biology ,Non-Fibrillar Collagens ,medicine.disease ,biology.organism_classification ,Recombinant Proteins ,Yeast ,Protein Structure, Tertiary ,Amino acid ,Cytoskeletal Proteins ,Solubility ,chemistry ,Biochemistry ,Recombinant DNA ,Collagen ,Bullous pemphigoid ,Carrier Proteins ,Biotechnology - Abstract
BP230 is a cytoskeletal linker protein of 2649 amino acids originally identified as the target autoantigen in bullous pemphigoid, a potentially devastating autoimmune skin blistering disorder. To better define its function, we sought to generate recombinant forms of BP230 in both Saccharomyces cerevisiae and Pichia pastoris after cloning its entire cDNA. By immunoblot analysis, full-length BP230 was not found in extracts of P. pastoris, whereas minor amounts of degraded BP230 were detected in extracts of S. cerevisiae. In contrast, both S. cerevisiae and P. pastoris were able to produce the 770-amino acid COOH-terminal domain of BP230. Furthermore, the production level of the recombinant BP230 tail in S. cerevisiae was significantly higher than that observed in P. pastoris and that of endogenous BP230 in cultured human keratinocytes. Finally, 12 of 17 (71%) BP sera recognized the recombinant BP230 protein in yeast extracts. Our results indicate that S. cerevisiae occasionally constitutes a better tool for recombinant protein production than P. pastoris. Although both its large size and poor solubility limit production of BP230, the developed yeast system provides cellular fractions enriched in BP230 recombinant proteins that constitute useful tools for the diagnosis of bullous pemphigoid.
- Published
- 2003
9. The Hemidesmosomal Protein Bullous Pemphigoid Antigen 1 and the Integrin β4 Subunit Bind to ERBIN
- Author
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Jean-Hilaire Saurat, Lionel Fontao, Arnoud Sonnenberg, Luca Borradori, Fabienne Jaunin, Reza Shafaatian, Bertrand Favre, and Jan Koster
- Subjects
Integrin beta4 ,Protein family ,Hemidesmosome ,Protein subunit ,PDZ domain ,Cell Biology ,Basolateral plasma membrane ,Biology ,Molecular Biology ,Biochemistry ,Dystonin ,Molecular biology ,Transmembrane protein - Abstract
The bullous pemphigoid antigen 1 (eBPAG1) is a constituent of hemidesmosomes (HDs), cell-substrate adhesion complexes in stratified epithelia. Although its COOH terminus interacts with intermediate filaments, its NH2 terminus is important for its recruitment into HDs. To identify proteins that interact with the NH2terminus of human eBPAG1, we performed a yeast two-hybrid screen, which uncovered a protein belonging to the LAP/LERP (for LRRand PDZ domain) protein family with 16 NH2-terminal leucine-rich repeats and a COOH-terminal PDZ domain. The gene for this LAP/LERP protein comprises at least 26 exons located on the long arm of chromosome 5. In most human tissues, several transcripts were detected differing in the coding region situated upstream of or within the PDZ domain. One of the encoded variants was found to correspond to the recently described protein ERBIN. In yeast and in vitro binding experiments, ERBIN was shown to interact not only with eBPAG1 but also with the COOH-terminal region of the cytoplasmic domain of the integrin β4 subunit, another component of HDs. Antibodies raised against the COOH terminus showed that ERBIN is expressed in keratinocytes. In transfected epithelial cells the protein, however, was not localized in HDs but was either diffusely distributed over the cytoplasm or concentrated at the basolateral plasma membrane. Because ERBIN had been shown previously to interact with the transmembrane tyrosine kinase receptor Erb-B2, which in turn associates with the integrin β4 subunit, we suggest that ERBIN provides a link between HD assembly and Erb-B2 receptor signaling.
- Published
- 2001
10. Regulation of the Type II Hemidesmosomal Plaque Assembly in Intestinal Epithelial Cells
- Author
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Jean-François Launay, Lionel Fontao, Jeanne Stutzmann, and Patrick Gendry
- Subjects
Integrins ,Cytochalasin B ,Immunoelectron microscopy ,Cell Count ,macromolecular substances ,Biology ,Vinblastine ,Microtubules ,Cell junction ,Extracellular matrix ,Intermediate Filament Proteins ,Cell Adhesion ,Tumor Cells, Cultured ,Humans ,Pseudopodia ,Intestinal Mucosa ,Intermediate filament ,Cytoskeleton ,Actin ,Cell Size ,Integrin alpha6beta4 ,Microscopy, Confocal ,Hemidesmosome ,Epithelial Cells ,Desmosomes ,Cell Biology ,Plectin ,Actins ,Vinculin ,Extracellular Matrix ,Cell biology ,Actin Cytoskeleton ,Microscopy, Electron ,Antigens, Surface ,Colonic Neoplasms ,Keratins - Abstract
Hemidesmosomes (HDs) are cellular junctions that anchor epithelial cells to the extracellular matrix (ECM) and are associated morphologically with the cytoskeleton. Hemidesmosomal molecular components include two proteins involved in linking intermediate filaments, HD1/plectin and BP230, and two transmembrane proteins, BP180 and the alpha6beta4 integrin, a laminin receptor. In cells lacking BP230 and BP180, HD1/plectin still associates with alpha6beta4 integrin, forming HD-like structures, called type II HDs. In the present study, we used an intestinal epithelial cell line that expresses HD1/plectin and the alpha6beta4 integrin to investigate the regulation of assembly of these proteins in type II HDs. These compounds were found to be clustered at sites of cell-ECM contact and their polarized localization was influenced by either cell confluency or extracellular matrix deposition. Conventional and immunoelectron microscopy showed that HD1/plectin and the beta4 integrin subunit are colocalized in an adhesion structure. Using cytoskeleton-disrupting drugs and confocal microscopy, we demonstrated that type II HDs are made up of numerous individual plaques whose assembly into a cluster requires actin filaments, but not microtubules.
- Published
- 1999
11. AhR binds a variety of structurally unrelated compounds with a wide range of potencies: Comparison between three bioassays
- Author
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Frédérique Ino, Olivier Sorg, Fabienne Fontao, Jean-Hilaire Saurat, N. Barouti, Vincent Piguet, and Lionel Fontao
- Subjects
Range (biology) ,Chemistry ,Bioassay ,General Medicine ,Toxicology ,Combinatorial chemistry - Published
- 2011
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