title: Not all injury-induced muscle proteolysis is due to increased activity of the ubiquitin/proteasome system: evidence for up-regulation of macrophage-associated lysosomal proteolysis in a model of local trauma.
abstract: A characteristic response to injury is a dramatic loss of skeletal muscle protein owing to increased muscle protein breakdown. Over the past decade, numerous studies have indicated that up-regulation of the ubiquitin-proteasome system is a common mechanism underlying such injury-induced muscle proteolysis. However, a recent study using a single-impact trauma to the gastrocnemius muscle found that, although the rate of muscle proteolysis was dramatically increased, the ubiquitin-proteasome system was not involved. Rather, an increase in lysosomal activity, through infiltration of the damaged tissue by mononuclear macrophages, is responsible for the high rates of protein breakdown.
authors.affiliation: Department of Nutritional Sciences, Thompson Hall, Cook College, Rutgers University, New Brunswick, NJ 08901, USA.
authors.forename: Malcolm
authors.initials: M
authors.lastname: Watford
mesh_terms: D000818:Animals; D008247:Lysosomes / Q000201:enzymology*; D008264:Macrophages / Q000201:enzymology*; D023421:Models, Animal; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D009124:Muscle Proteins; D025801:Ubiquitin; D010447:Peptide Hydrolases