title: The Caveolin-3 G56S sequence variant of unknown significance: Muscle biopsy findings and functional cell biological analysis.
abstract: In the era of next-generation sequencing, we are increasingly confronted with sequence variants of unknown significance. This phenomenon is also known for variations in Caveolin-3 and can complicate the molecular diagnosis of the disease. Here, we aimed to study the ambiguous character of the G56S Caveolin-3 variant.
  
  
  
  A comprehensive approach combining genetic and morphological studies of muscle derived from carriers of the G56S Caveolin-3 variant were carried out and linked to biochemical assays (including phosphoblot studies and proteome profiling) and morphological investigations of cultured myoblasts.
  
  
  
  Muscles showed moderate chronic myopathic changes in all carriers of the variant. Myogenic RCMH cells expressing the G56S Caveolin-3 protein presented irregular Caveolin-3 deposits within the Golgi in addition to a regular localization of the protein to the plasma membrane. This result was associated with abnormal findings on the ultra-structural level. Phosphoblot studies revealed that G56S affects EGFR-signaling. Proteomic profiling demonstrated alterations in levels of physiologically relevant proteins which are indicative for antagonization of G56S Caveolin-3 expression. Remarkably, some proteomic alterations were enhanced by osmotic/mechanical stress.
  
  
  
  Our studies suggest that G56S might influence the manifestation of myopathic changes upon the presence of additional cellular stress burden. Results of our studies moreover improve the current understanding of (genetic) causes of myopathic disorders classified as caveolinopathies.
authors.affiliation: Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Brauers
authors.affiliation: Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.|Leibniz-Institut für Analytische Wissenschaften - ISAS e.V, Dortmund, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Roos
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS e.V, Dortmund, Germany.
authors.forename: Laxmikanth
authors.initials: L
authors.lastname: Kollipara
authors.affiliation: Leibniz-Institut für Analytische Wissenschaften - ISAS e.V, Dortmund, Germany.
authors.forename: René P
authors.initials: RP
authors.lastname: Zahedi
authors.affiliation: Medizinisches Versorgungszentrum Dr. Eberhard und Partner, Dortmund, Germany.
authors.forename: Alf
authors.initials: A
authors.lastname: Beckmann
authors.affiliation: Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Nilane
authors.initials: N
authors.lastname: Mohanadas
authors.affiliation: Department of Neurology, Marien-Hospital, Euskirchen, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Bauer
authors.affiliation: Department of Pediatrics, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Häusler
authors.affiliation: Bld. de la Pétrusse 98, Luxembourg, Luxembourg.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Thoma
authors.affiliation: Institute of Human Genetics, University of Würzburg, Würzburg, Germany.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kress
authors.affiliation: Friedrich-Baur-Institut, Neurologische Klinik und Poliklinik, Ludwig-Maximilians-University, München, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Senderek
authors.affiliation: Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Weis
mesh_terms: D000293:Adolescent; D000328:Adult; D051244:Caveolin 3 / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D004576:Electromyography; D066246:ErbB Receptors / Q000378:metabolism; D005260:Female; D006579:Heterozygote; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D009135:Muscular Diseases / Q000235:genetics* / Q000473:pathology; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D020543:Proteome / Q000032:analysis; D040901:Proteomics; D017422:Sequence Analysis, DNA; D053719:Tandem Mass Spectrometry
chemical_list: D051244:Caveolin 3; D020543:Proteome; D004247:DNA; D066246:ErbB Receptors
keywords: Caveolin-3; LGMD-1C; Proteome profile of muscle cells; RCMH