Details

Autor(en) / Beteiligte

• Schule, T
• Rose, M
• Entian, K.D
• Thumm, M
• Wolf, D.H

Titel

Ubc8p functions in catabolite degradation of fructose-1,6-bisphosphatase in yeast

Ist Teil von

• The EMBO journal, 2000-05, Vol.19 (10), p.2161-2167

Ort / Verlag

Chichester, UK: John Wiley & Sons, Ltd

Erscheinungsjahr

2000

Quelle

MEDLINE

Beschreibungen/Notizen

• The key gluconeogenic enzyme fructose‐1,6‐bisphosphatase (FBPase) is synthesized when cells of the yeast Saccharomyces cerevisiae are grown on a non‐fermentable carbon source. After shifting the cells to glucose‐containing medium, in a process called catabolite degradation, FBPase is selectively and rapidly broken down. We have isolated gid mutants, which are defective in this glucose‐induced degradation process. When complementing the defect in catabolite degradation of FBPase in gid3‐1 mutant cells with a yeast genomic library, we identified the GID3 gene and found it to be identical to UBC8 encoding the ubiquitin‐conjugating enzyme Ubc8p. The in vivo function of Ubc8p (Gid3p) has remained a mystery so far. Here we demonstrate the involvement of Ubc8p in the glucose‐induced ubiquitylation of FBPase as a prerequisite for catabolite degradation of the enzyme via the proteasome. Like FBPase, Ubc8p is found in the cytoplasmic fraction of the cell. We demonstrate cytoplasmic degradation of FBPase.