title: Altered distribution of plectin/HD1 in dystrophinopathies.
abstract: Plectin/HD1 is a high molecular weight protein (approximately 500 kDa) that has been proposed to act as an important and versatile cytoskeletal cross-linker molecule. Mutations of the human plectin gene have recently been associated with the autosomal recessive disorder epidermolysis bullosa simplex with muscular dystrophy. We studied the expression of plectin/HD1 in various neuromuscular disorders by indirect immunofluorescence. In cross sections of normal human muscle, plectin/HD1 showed a checkerboard-like distribution with moderate to intense cytoplasmic and sarcolemmal staining in type 1 fibers and a faint staining of the sarcolemma in type 2 fibers. In longitudinal sections of plectin/HD1-positive fibers a cross-striation staining pattern was noted. This fiber type-related expression was significantly altered in the group of dystrophinopathies, whereas it was maintained in all other myopathies and denervating disorders. In seven dystrophinopathies studied, a markedly increased plectin/HD1 immunoreactivity at the sarcolemmal level of type 2 fibers was observed. Confocal laser microscopy of normal skeletal muscle revealed a colocalization of desmin and plectin/HD1 at the level of the sarcolemma. This suggests that plectin/HD1- in analogy to its demonstrated involvement in cytokeratin-hemidesmosome linkage in epidermis-may mediate the anchorage of desmin to the sarcolemma (i.e. to costameres).
authors.affiliation: Neurologische Klinik und Poliklinik, Universität Bonn, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Schröder
authors.forename: R R
authors.initials: RR
authors.lastname: Mundegar
authors.forename: M
authors.initials: M
authors.lastname: Treusch
authors.forename: U
authors.initials: U
authors.lastname: Schlegel
authors.forename: I
authors.initials: I
authors.lastname: Blümcke
authors.forename: K
authors.initials: K
authors.lastname: Owaribe
authors.forename: T M
authors.initials: TM
authors.lastname: Magin
mesh_terms: D015139:Blotting, Southern; D015153:Blotting, Western; D005796:Genes; D006801:Humans; D007381:Intermediate Filament Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D018482:Muscle, Skeletal / Q000737:chemistry / Q000648:ultrastructure; D009136:Muscular Dystrophies / Q000378:metabolism; D009468:Neuromuscular Diseases / Q000378:metabolism*; D051190:Plectin
chemical_list: D007381:Intermediate Filament Proteins; C495332:PLEC protein, human; D051190:Plectin