Abstract
Senescent cells have less free ubiquitin and more ubiquitin-protein conjugates than do young cells. The ubiquitin-protein conjugates are heterogeneous in size but contain prominent bands at 106, 55, and 22 kDa. The age-related increase in ubiquitin-protein conjugates applies primarily to the 55-kDa band, while the 106-kDa and 22-kDa conjugates change little with age. Ubiquitin mRNA levels do not change with age, and the ability of cells to degrade two proteins that are good substrates for ubiquitin-mediated proteolysis is unaltered by aging. These results indicate that an increase in ubiquitin-protein conjugates does not necessarily reflect alterations in ubiquitin-mediated proteolysis. Furthermore, an overactive pathway of ubiquitin-mediated proteolysis does not appear to contribute to the proliferative arrest in senescent cells.
Original language | English (US) |
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Pages (from-to) | 39-49 |
Number of pages | 11 |
Journal | Experimental Gerontology |
Volume | 28 |
Issue number | 1 |
DOIs | |
State | Published - 1993 |
ASJC Scopus subject areas
- Biochemistry
- Aging
- Molecular Biology
- Genetics
- Endocrinology
- Cell Biology