Glucose activation of the yeast plasma membrane H+-ATPase requires the ubiquitin-proteasome proteolytic pathway.
Glucose triggers transcriptional and post-transcriptional mechanisms that increase the level and activity of Saccharomyces cerevisiae plasma membrane H+-ATPase. We have studied the post-transcriptional activation of the enzyme by glucose and have found that Rsp5, a ubiquitin-protein ligase enzyme, Ubc4, a ubiquitin-conjugating enzyme, and the 26S proteasome complex are implicated in this activation. These results suggest that ATPase activation by glucose requires the ubiquitin-proteasome proteolytic pathway. This is supported by the fact that over-expression of the ubiquitin-specific protease Ubp2, which cleaves ubiquitin from its branched conjugates, inhibits this activation. We propose that glucose triggers degradation of an inhibitory protein resulting in enzyme activation.
de la Fuente
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Departamento de Bioquímica, Facultad de Medicina, Universidad Autónoma de Madrid and Instituto de Investigaciones Biomédicas del Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Maldonado
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AM
Portillo
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F
D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D010450:Endopeptidases / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport; D004789:Enzyme Activation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005947:Glucose / Q000494:pharmacology*; D007700:Kinetics; D008025:Ligases / Q000378:metabolism; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D014452:Ubiquitins / Q000378:metabolism*
D056827:Endosomal Sorting Complexes Required for Transport; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; C063109:ubiquitin-conjugating enzyme UBC4; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C059237:ubiquitin-Nalpha-protein hydrolase; D006180:Proton-Translocating ATPases; D008025:Ligases; C469287:RSP5 protein, S cerevisiae; D005947:Glucose