Abstract
MafBx and Murf are two new rat E3 ubiquitin ligases induced in muscle atrophy. Our goal was to investigate whether lipopolysaccharide (LPS) injection, a model of muscle catabolism, is associated with increased expression of MafBx and Murf. LPS (750 microg/100 g body weight) induces MafBx and Murf mRNA (respectively, 23-fold and 33-fold after 12 h; P<0.001). A transient induction of tumor necrosis factor-alpha mRNA (21-fold; P<0.001 at 3 h) and a decrease of insulin like growth factor-I mRNA (50%; P<0.001 at 6 h), two potential regulators of the ubiquitin-proteasome system were also demonstrated. In summary, MafBx and Murf mRNA are up-regulated in response to LPS and might play a role in the muscle proteolysis observed.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Body Weight
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Ligases / metabolism*
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Lipopolysaccharides / metabolism*
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Muscle Proteins / metabolism*
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Muscle, Skeletal / drug effects
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Muscle, Skeletal / metabolism*
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Muscles / metabolism
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RNA / metabolism
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RNA, Messenger / metabolism
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Rats
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Rats, Wistar
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Reverse Transcriptase Polymerase Chain Reaction
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SKP Cullin F-Box Protein Ligases*
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Time Factors
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Tripartite Motif Proteins
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Tumor Necrosis Factor-alpha / metabolism
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Ubiquitin-Protein Ligases*
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Up-Regulation
Substances
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Lipopolysaccharides
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Muscle Proteins
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RNA, Messenger
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Tripartite Motif Proteins
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Tumor Necrosis Factor-alpha
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RNA
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FBXO32 protein, human
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Fbxo32 protein, rat
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SKP Cullin F-Box Protein Ligases
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TRIM63 protein, human
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Trim63 protein, rat
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Ubiquitin-Protein Ligases
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Ligases