E. Mamroudkidron et al., THE 20S PROTEASOME MEDIATES THE DEGRADATION OF MOUSE AND YEAST ORNITHINE DECARBOXYLASE IN YEAST-CELLS, FEBS letters, 337(3), 1994, pp. 239-242
Ornithine decarboxylase (ODC), a key enzyme in the biosynthesis of pol
yamines, is one of the most rapidly degraded proteins in mammalian cel
ls. Recently it has been demonstrated that mammalian ODC is degraded i
n vitro by the 26S protease that contains the 20S proteasome as its ca
talytic core, in a reaction that does not require ubiquitin. Here, we
show that yeast and mouse ODC are both rapidly degraded in yeast cells
and that their degradation severely inhibited in a mutant yeast cell
line defective in the chymotryptic activity of proteinase yscE, the ye
ast 20S proteasome. These results provide compelling genetic support t
o previous biochemical studies suggesting the involvement of the 20S p
roteasome in the degradation of ornithine decarboxylase.