Mode of action of the qcr9 and cat3 mutations in restoring the ability of Saccharomyces cerevisiae tps1 mutants to grow on glucose.
Mutations in the TPS1 gene, which encodes trehalose-6-P synthase, cause a glucose-negative phenotype in Saccharomyces cerevisiae. Antimycin A or disruption of the QCR9 gene, which encodes one subunit of the cytochrome bc1 complex, restore the ability to grow in glucose-containing media. Under these conditions the cell excreted a large amount of glycerol, corresponding to about 20% of the glucose taken up. Suppression appears to be achieved by diversion of accumulated glycolytic intermediates to the production of glycerol, thereby providing NAD+ and phosphate for the glyceraldehyde-3-P dehydrogenase reaction. Analysis of the mutation sci1-1, which also suppresses the glucose-negative phenotype of tps1 mutants, showed that glucose transport was decreased in sci1-1 mutants. The gene SCI1 was cloned and its nucleotide sequence revealed it to be identical to CAT3/SNF4. The suppression mediated by sci1-1 is attributable to a decrease in glycolytic flux.
Unidad de Bioquímica y Genética de Levaduras, Instituto de Investigaciones Biomédicas del C.S.I.C., Madrid, Spain.
M A
MA
Blázquez
C
C
Gancedo
D055372:AMP-Activated Protein Kinases; D000968:Antimycin A / Q000494:pharmacology; D001692:Biological Transport; D002352:Carrier Proteins; D003001:Cloning, Molecular; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000235:genetics*; D005285:Fermentation / Q000187:drug effects; D005656:Fungal Proteins / Q000235:genetics; D005947:Glucose / Q000378:metabolism*; D005964:Glucosyltransferases / Q000235:genetics*; D005990:Glycerol / Q000378:metabolism; D016296:Mutagenesis; D009154:Mutation; D010101:Oxygen Consumption / Q000187:drug effects; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017422:Sequence Analysis, DNA; D013489:Suppression, Genetic; D014157:Transcription Factors / Q000235:genetics*
D002352:Carrier Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000968:Antimycin A; D005964:Glucosyltransferases; C023180:trehalose-6-phosphate synthase; D011494:Protein Kinases; C078651:SNF4 protein, S cerevisiae; D055372:AMP-Activated Protein Kinases; D014450:Electron Transport Complex III; D005947:Glucose; D005990:Glycerol