Selective loss of sarcolemmal nitric oxide synthase in Becker muscular dystrophy.
Becker muscular dystrophy is an X-linked disease due to mutations of the dystrophin gene. We now show that neuronal-type nitric oxide synthase (nNOS), an identified enzyme in the dystrophin complex, is uniquely absent from skeletal muscle plasma membrane in many human Becker patients and in mouse models of dystrophinopathy. An NH2-terminal domain of nNOS directly interacts with alpha 1-syntrophin but not with other proteins in the dystrophin complex analyzed. However, nNOS does not associate with alpha 1-syntrophin on the sarcolemma in transgenic mdx mice expressing truncated dystrophin proteins. This suggests a ternary interaction of nNOS, alpha 1-syntrophin, and the central domain of dystrophin in vivo, a conclusion supported by developmental studies in muscle. These data indicate that proper assembly of the dystrophin complex is dependent upon the structure of the central rodlike domain and have implications for the design of dystrophin-containing vectors for gene therapy.
Chao
D S
DS
Department of Physiology, University of California at San Francisco School of Medicine 94143-0444, USA.
Gorospe
J R
JR
Brenman
J E
JE
Rafael
J A
JA
Peters
M F
MF
Froehner
S C
SC
Hoffman
E P
EP
Chamberlain
J S
JS
Bredt
D S
DS
D000818:Animals; D001706:Biopsy; D002135:Calcium-Binding Proteins; D003598:Cytoskeletal Proteins / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D009136:Muscular Dystrophies / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D049031:Sarcoglycans; D012508:Sarcolemma / Q000201:enzymology; D049411:Utrophin
D002135:Calcium-Binding Proteins; D003598:Cytoskeletal Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D049031:Sarcoglycans; C483600:Utrn protein, mouse; D049411:Utrophin; C091825:syntrophin alpha1; D019001:Nitric Oxide Synthase