Inhibition of proteasome function prevents thymocyte apoptosis: Involvement of ornithine decarboxylase

Emanuela Grassilli, Francesca Benatti, Paola Dansi, Anna Maria Giammarioli, Walter Malorni, Claudio Franceschi, Maria Alfonsina Desiderio

Research output: Contribution to journalArticlepeer-review


We have previously shown that polyamine levels rapidly decrease in thymocytes undergoing apoptosis, and that ornithine decarboxylase increases early but too transiently to maintain elevated polyamine levels. These data led us to suppose that a precocious ornithine decarboxylase degradation might be responsible for the imbalance of polyamine metabolism. Ornithine decarboxylase is known to be degraded by the cytosolic 26S proteasome that plays an essential role in thymocyte apoptosis. In this paper we demonstrate that the inhibition of proteasome function preserves ornithine decarboxylase activity and prevents thymocytes from undergoing apoptosis after dexamethasone treatment. Since intracellular polyamine levels are also preserved, ornithine decarboxylase seems to be functionally active in maintaining polyamine homeostasis after proteasome inhibition in thymocytes. Our proposed role for the proteasome in quiescent cells upon an apoptotic stimulus is to degrade proteins like ornithine decarboxylase that are involved in the control of the cell cycle and cell survival.

Original languageEnglish
Pages (from-to)293-297
Number of pages5
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - Sept 18 1998

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


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