Ubiquitin pools, ubiquitin mRNA levels, and ubiquitin-mediated proteolysis in aging human fibroblasts

Jia Xiu Pan, Sharla R. Short, Stephen A. Goff, J. Fred Dice

Research output: Contribution to journalArticle

26 Scopus citations

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 languageEnglish (US)
Pages (from-to)39-49
Number of pages11
JournalExperimental Gerontology
Volume28
Issue number1
DOIs
StatePublished - Jan 1 1993

ASJC Scopus subject areas

  • Biochemistry
  • Aging
  • Molecular Biology
  • Genetics
  • Endocrinology
  • Cell Biology

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