title: Skelemin, a cytoskeletal M-disc periphery protein, contains motifs of adhesion/recognition and intermediate filament proteins.
abstract: In striated muscle, myofibrils are anchored to an interconnecting cytoskeleton of desmin intermediate filaments. Skelemin (195 kDa) may be a link between myofibrils and the intermediate filament cytoskeleton. Skelemin partitions with desmin to the insoluble cytoskeleton, and increases the thickness of reconstituted intermediate filaments. Concentrated at the M-disc periphery, skelemin may also contact myosin filaments. We used immunoscreening to isolate a mouse muscle cDNA which encodes a protein with a calculated molecular mass of 185 kDa. Anti-skelemin antibodies bound to the protein products of each of three nonoverlapping regions of the open reading frame. Antibodies directed against the protein products of each one-third of the cDNA react with a 195-kDa muscle protein and stain the M-disc indistinguishably from the original anti-skelemin antibodies, suggesting that the cDNA encodes skelemin. A single skelemin mRNA is detected in muscle but not non-muscle tissues, consistent with immunostaining results. Skelemin is a member of a family of myosin-associated proteins containing fibronectin type III and immunoglobulin superfamily C2 motifs. Skelemin is unique in this family in having intermediate filament core-like motifs, one near each terminus. We hypothesize that skelemin could interact with myosin or myosin-associated proteins through its fibronectin and/or immunoglobulin motifs, and with intermediate filaments through intermediate filament-like motifs.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251-1892.
authors.forename: M G
authors.initials: MG
authors.lastname: Price
authors.forename: R H
authors.initials: RH
authors.lastname: Gomer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002478:Cells, Cultured; D064211:Connectin; D006224:Cricetinae; D003598:Cytoskeletal Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary; D007381:Intermediate Filament Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins; D009132:Muscles / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D015815:Cell Adhesion Molecules; D064211:Connectin; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D007381:Intermediate Filament Proteins; D009124:Muscle Proteins; C577300:Myom1 protein, mouse; D012333:RNA, Messenger