Changes in 20S proteasome activity during ageing of the LOU rat.
Muscular functions decline and muscle mass decreases during ageing. In the rat, there is a 27% decrease in muscle protein between 18 and 34 months of age. We examined age-related changes in the proteasome-dependent proteolytic pathway in rats at 4, 18, 24, 29 and 34 months of age. The three best characterised activities of the proteasome (chymotrypsin-like, trypsin-like and peptidylglutamyl peptide hydrolase) increased to 29 months and then decreased in the senescent animal. These variations in activity were accompanied by an identical change in the quantity of 20S proteasome measured by Western blot, whereas the S4 subunit of the 19S regulator and the quantity of ubiquitin-linked proteins remained constant. mRNA of subunits C3, C5, C9, and S4 increased in the senescent animal, but ubiquitin mRNA levels were unchanged. These findings suggest that the 20S proteasome may be partly responsible for the muscular atrophy observed during ageing in the rat.
Bardag-Gorce
F
F
Université Blaise Pascal Clermont 2, Laboratoire de Biochimie Appliquée-EA 995, Aubiere, France.
Farout
L
L
Veyrat-Durebex
C
C
Briand
Y
Y
Briand
M
M
D000375:Aging / Q000378:metabolism*; D000818:Animals; D001284:Atrophy; D015153:Blotting, Western; D001835:Body Weight; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008297:Male; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D046988:Proteasome Endopeptidase Complex; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism
D009097:Multienzyme Complexes; D012333:RNA, Messenger; D014452:Ubiquitins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex