Sarcospan, the 25-kDa transmembrane component of the dystrophin-glycoprotein complex.
Affiliation
Howard Hughes Medical Institute, Department of Physiology and Biophysics, University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.Issue Date
1997-12-12
Metadata
Show full item recordAbstract
The dystrophin-glycoprotein complex is a multisubunit protein complex that spans the sarcolemma and forms a link between the subsarcolemmal cytoskeleton and the extracellular matrix. Primary mutations in the genes encoding the proteins of this complex are associated with several forms of muscular dystrophy. Here we report the cloning and characterization of sarcospan, a unique 25-kDa member of this complex. Topology algorithms predict that sarcospan contains four transmembrane spanning helices with both N- and C-terminal domains located intracellularly. Phylogenetic analysis reveals that sarcospan's arrangement in the membrane as well as its primary sequence are similar to that of the tetraspan superfamily of proteins. Sarcospan co-localizes and co-purifies with the dystrophin-glycoprotein complex, demonstrating that it is an integral component of the complex. We also show that sarcospan expression is dramatically reduced in muscle from patients with Duchenne muscular dystrophy. This suggests that localization of sarcospan to the membrane is dependent on proper dystrophin expression. The gene encoding sarcospan maps to human chromosome 12p11.2, which falls within the genetic locus for congenital fibrosis of the extraocular muscle, an autosomal dominant muscular dystrophy.Citation
Sarcospan, the 25-kDa transmembrane component of the dystrophin-glycoprotein complex. 1997, 272 (50):31221-4 J. Biol. Chem.Journal
The Journal of Biological ChemistryDOI
10.1074/jbc.272.50.31221PubMed ID
9395445Type
ArticleLanguage
enISSN
0021-9258ae974a485f413a2113503eed53cd6c53
10.1074/jbc.272.50.31221