Mikaela Lindfors, Sini Penttilä, H. Luque, Talita C. Conte, Bernard Brais, Giorgio Tasca, Bruno Eymard, Karine Charton, Isabelle Richard, Anna Vihola, Marco Savarese, F. Leturcq, Bjarne Udd, Lääketieteen ja biotieteiden tiedekunta - Faculty of Medicine and Life Sciences, University of Tampere, University of Helsinki, Tampere University Hospital, Hôpital Cochin [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Institut de Myologie, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Association française contre les myopathies (AFM-Téléthon)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università cattolica del Sacro Cuore [Roma] (Unicatt), McGill University = Université McGill [Montréal, Canada], Approches génétiques intégrées et nouvelles thérapies pour les maladies rares (INTEGRARE), Université d'Évry-Val-d'Essonne (UEVE)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Généthon-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Vaasa Central Hospital, CHU Cochin [AP-HP], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Association française contre les myopathies (AFM-Téléthon)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Università Cattolica del Sacro Cuore [Roma] (Unicatt), McGill University, Immunologie moléculaire et biothérapies innovantes, École pratique des hautes études (EPHE)-Université d'Évry-Val-d'Essonne (UEVE)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Genethon, École pratique des hautes études (EPHE)-Université d'Évry-Val-d'Essonne (UEVE)-GENETHON 3-Institut National de la Santé et de la Recherche Médicale (INSERM), Richard, Isabelle, Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Università cattolica del Sacro Cuore = Catholic University of the Sacred Heart [Roma] (Unicatt), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Évry-Val-d'Essonne (UEVE)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Généthon, and École Pratique des Hautes Études (EPHE)
Aims Previously, detection of ANO5 protein has been complicated by unspecific antibodies, most of which have not identified the correct protein. The aims of the study were to specify ANO5 protein expression in human skeletal muscle, and to investigate if the ANO5 protein levels are affected by different ANO5 mutations in anoctaminopathy patients. Methods Four different antibodies were tested for ANO5 specificity. A sample preparation method compatible with membrane proteins, combined with tissue fractionation was used to determine ANO5 expression in cell cultures expressing ANO5, in normal muscles and eight patient biopsies with six different ANO5 mutations in homozygous or compound heterozygous states, and in other dystrophies. Results Only one specific monoclonal N-terminal ANO5 antibody was efficient in detecting the protein, showing that ANO5 is expressed as a single 107 kD polypeptide in human skeletal muscle. The truncating mutations c.191dupA and c.1261C>T were found to abolish ANO5 expression, whereas the studied point mutations had variable effects, however, all the ANO5 mutations resulted in clearly reduced ANO5 expression in the patient muscle membrane fraction. Attempts to detect ANO5 using immunohistochemistry were not yet successful. Conclusions The data presented here indicate that the ANO5 protein expression is decreased in ANO5-mutated muscular dystrophy and that most of the non-truncating pathogenic ANO5 mutations likely destabilize the protein and cause its degradation. The method described here allows direct analysis of human ANO5 protein, which can be used in diagnostics, for evaluating the pathogenicity of the potentially harmful ANO5 variants of uncertain significance. This article is protected by copyright. All rights reserved.