scholarly journals Sepsis is associated with increased mRNAs of the ubiquitin-proteasome proteolytic pathway in human skeletal muscle.

1997 ◽  
Vol 99 (2) ◽  
pp. 163-168 ◽  
Author(s):  
G Tiao ◽  
S Hobler ◽  
J J Wang ◽  
T A Meyer ◽  
F A Luchette ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome

Burn injury upregulates the activity and gene expression of the 20 S proteasome in rat skeletal muscle

2000 ◽  
Vol 99 (3) ◽  
pp. 181-187 ◽  
Author(s):  
Cheng-Hui FANG ◽  
Bing-Guo LI ◽  
David R. FISCHER ◽  
Jing Jing WANG ◽  
Herbert A. RUNNELS ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Burn Injury ◽  
Catalytic Core ◽  
Peptide Substrates ◽  
Protein Substrates ◽  
Proteolytic Pathway ◽  
Proteasome Subunits ◽  
Ubiquitin Proteasome ◽  
Dependent Protein ◽  
Increased Activity

There is evidence that burn injury stimulates ubiquitin–proteasome-dependent protein breakdown in skeletal muscle. In this proteolytic pathway, protein substrates are conjugated to multiple molecules of ubiquitin, whereafter they are recognized, unfolded and degraded by the multicatalytic 26 S protease complex. The 20 S proteasome is the catalytic core of the 26 S protease complex. The influence of burn injury on the expression and activity of the 20 S proteasome has not been reported. We tested the hypothesis that burn injury increases 20 S proteasome activity and the expression of mRNA for the 20 S proteasome subunits RC3 and RC7. Proteolytic activity of isolated 20 S proteasomes, assessed as activity against fluorogenic peptide substrates, was increased in extensor digitorum longus muscles from burned rats. Northern-blot analysis revealed that the expression of mRNA for RC3 and RC7 was increased by 100% and 80% respectively following burn injury. Increased activity and expression of the 20 S proteasome in muscles from burned rats support the concept that burn-induced muscle cachexia is at least, in part, regulated by the ubiquitin–proteasome proteolytic pathway.

Activity and expression of the 20S proteasome are increased in skeletal muscle during sepsis

1999 ◽  
Vol 277 (2) ◽  
pp. R434-R440 ◽  
Author(s):  
Scott C. Hobler ◽  
Arthur Williams ◽  
David Fischer ◽  
Jing Jing Wang ◽  
Xiaoyan Sun ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Proteolytic Activity ◽  
Blot Analysis ◽  
20S Proteasome ◽  
Catalytic Core ◽  
Proteolytic Pathway ◽  
Ubiquitin Proteasome ◽  
Dependent Protein ◽  
26S Protease

Recent studies suggest that sepsis stimulates ubiquitin-dependent protein breakdown in skeletal muscle. In this proteolytic pathway, ubiquitinated proteins are recognized, unfolded, and degraded by the multicatalytic 26S protease complex. The 20S proteasome is the catalytic core of the 26S protease complex. The role of the 20S proteasome in the regulation of sepsis-induced muscle proteolysis is not known. We tested the hypothesis that sepsis increases 20S proteasome activity and the expression of mRNA for various subunits of this complex. Proteolytic activity of isolated 20S proteasomes, assessed as activity against fluorogenic peptide substrates, was increased in extensor digitorum longus muscles from septic rats. The proteolytic activity was inhibited by specific proteasome blockers. Northern blot analysis revealed an approximately twofold increase in the relative abundance of mRNA for the 20S α-subunits RC3 and RC9 and the β-subunit RC7. However, Western blot analysis did not show any difference in RC9 protein content between sham-operated and septic rats. The increased activity and expression of the 20S proteasome in muscles from septic rats lend further support for a role of the ubiquitin-proteasome-pathway in the regulation of sepsis-induced muscle proteolysis.

Sign in / Sign up

Export Citation Format

Share Document