Role of ubiquitin-proteasome-dependent proteolytic process in degradation of muscle protein from diabetic rabbits.
The activity of ATP, ubiquitin (Ub)-dependent proteases partially purified from skeletal muscle (psoas) from alloxan diabetic rabbits was determined at different periods of insulin deficiency. Two days after alloxan injection, no change was observed in the activity of ATP, Ub-dependent proteases, but this activity increased 3 and 5 days after diabetes induction, attaining 181% of control values on the 5th day. However, after this early rise, the activity of muscle ATP, Ub-dependent proteases decreased, returning to values that did not differ significantly from controls 7 and 10 days after alloxan injection. After 15 days, the activity of these proteases was 57% lower than in muscle from control rabbits. Both the initial increase and the subsequent fall in the activity of the enzymes were prevented by insulin treatment of alloxan diabetic rabbits. The data suggest that Ub-proteasome-dependent proteolysis have an important role in the control of muscle protein degradation and may be regulated by insulin.
Galban
V D
VD
Department of Biochemistry and Immunology, Ribeirão Preto Medical School, São Paulo University, Brazil.
Evangelista
E A
EA
Migliorini
R H
RH
do Carmo Kettelhut
I
I
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005227:Fatty Acids / Q000097:blood; D007328:Insulin / Q000494:pharmacology; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011817:Rabbits; D013997:Time Factors; D014452:Ubiquitins / Q000378:metabolism*
D001786:Blood Glucose; D005227:Fatty Acids; D007328:Insulin; D009097:Multienzyme Complexes; D009124:Muscle Proteins; D014452:Ubiquitins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex