Catabolite inactivation of fructose-1,6-bisphosphatase of Saccharomyces cerevisiae. Degradation occurs via the ubiquitin pathway.
Catabolite inactivation of fructose-1,6-bisphosphatase (FBPase), a key enzyme in gluconeogenesis, is due to phosphorylation and subsequent degradation in the yeast Saccharomyces cerevisiae. The degradation process of the enzyme had been shown to depend on the action of the proteasome. Here we report that components of the ubiquitin pathway target FBPase to proteolysis. Upon glucose addition to yeast cells cultured on nonfermentable carbon sources FBPase is ubiquitinated in vivo. A multiubiquitin chain containing isopeptide linkages at Lys48 of ubiquitin is attached to FBPase. Formation of a multiubiquitin chain is a prerequisite for the degradation of FBPase. Catabolite degradation of FBPase is dependent on the ubiquitin-conjugating enzymes Ubc1, Ubc4, and Ubc5. The 26 S proteasome is involved in the degradation process.
Schork
S M
SM
Institut für Biochemie, Universität Stuttgart, Germany.
Thumm
M
M
Wolf
D H
DH
D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000378:metabolism; D005246:Feedback; D006597:Fructose-Bisphosphatase / Q000037:antagonists & inhibitors*; D015870:Gene Expression; D005800:Genes, Fungal; D005947:Glucose / Q000494:pharmacology; D007700:Kinetics; D008025:Ligases / Q000096:biosynthesis / Q000378:metabolism*; D008239:Lysine; D009097:Multienzyme Complexes / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000378:metabolism*
D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; C066752:UBC1 protein, S cerevisiae; C489270:UBC5 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; C063109:ubiquitin-conjugating enzyme UBC4; D006597:Fructose-Bisphosphatase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D008025:Ligases; D005947:Glucose; D008239:Lysine