Abstract
Increased expression of critical components of the ubiquitin-dependent proteolytic pathway occurs in any muscle wasting condition so far studied in rodents where proteolysis rises. We have recently reported similar adaptations in head trauma patients [Mansoor et al. (1996) Proc. Natl. Acad. Sci. USA 93, 2714-2718]. We demonstrate here that the increased muscle protein breakdown seen in mdx mice only correlated with enhanced expression of m-calpain, a Ca(2+)-activated proteinase. By contrast, no change in mRNA levels for components of the ubiquitin-proteasome proteolytic process was seen in muscles from both mdx mice and Duchenne muscular dystrophy patients. Thus, gene expression of components of this pathway is not regulated in the chronic wasting that characterizes muscular dystrophy.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adolescent
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Animals
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Calpain / biosynthesis
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Cathepsin D / biosynthesis
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Cathepsin L
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Cathepsins / biosynthesis
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Child
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Cysteine Endopeptidases / biosynthesis*
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Cysteine Endopeptidases / genetics
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Dystrophin / deficiency*
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Endopeptidases*
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Female
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Fibrosis
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Gene Expression
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Humans
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Male
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Mice
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Mice, Inbred mdx
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Multienzyme Complexes / biosynthesis*
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Multienzyme Complexes / genetics
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Muscle, Skeletal / metabolism
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Muscle, Skeletal / pathology
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Muscular Dystrophies / metabolism*
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Muscular Dystrophies / pathology
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Muscular Dystrophies / physiopathology
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Necrosis
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Proteasome Endopeptidase Complex
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RNA, Messenger / analysis
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Reference Values
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Transcription, Genetic*
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Ubiquitins / biosynthesis*
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Ubiquitins / genetics
Substances
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Dystrophin
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Multienzyme Complexes
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RNA, Messenger
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Ubiquitins
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Cathepsins
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Endopeptidases
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Calpain
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Cysteine Endopeptidases
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CTSL protein, human
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Cathepsin L
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Ctsl protein, mouse
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Cathepsin D
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Proteasome Endopeptidase Complex