FIG. 5.

Doa4p and Ump1p are required for Ume3p degradation in response to oxidative stress. Log-phase wild-type (RSY10), doa4 mutant (MHY623) and ump1 mutant (JD59) cultures harboring pKC337 were subjected to ethanol shock (A) or oxidative stress (B) as described previously. Samples were taken prior to stress treatment (0 min) and at subsequent times as indicated. Protein extracts from these samples were prepared, and Ume3p levels were determined by Western blot analysis. The vector lane controls for nonspecific binding of the myc monoclonal antibody. Tub1p levels served as protein loading controls.