title: SIT4 regulation of Mig1p-mediated catabolite repression in Saccharomyces cerevisiae.
abstract: E153 is a respiratory deficient mutant of Saccharomyces cerevisiae with a mutation in the active site of the Sit4p protein phosphatase. Measurements of mitochondrial respiration and cytochromes indicate that the mutation suppresses glucose repression. The escape from catabolite repression is accompanied by a marked reduction of the transcriptional repressor Mig1p. The presence of normal levels of MIG1 mRNA in the mutant and its association with the polysome fraction suggests that depletion of Mig1p is the result of protein degradation. This study shows that in addition to phosphorylation by Snf1p, the transcriptional repressor activity of Mig1p is also regulated by a post-transcriptional Sit4p-dependent pathway. Our evidence suggests that this pathway involves turnover of Mig1p.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
authors.forename: Can
authors.initials: C
authors.lastname: Jin
authors.forename: Antoni
authors.initials: A
authors.lastname: Barrientos
authors.forename: Charles B
authors.initials: CB
authors.lastname: Epstein
authors.forename: Ronald A
authors.initials: RA
authors.lastname: Butow
authors.forename: Alexander
authors.initials: A
authors.lastname: Tzagoloff
mesh_terms: D000483:Alleles; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D008954:Models, Biological; D009154:Mutation; D010641:Phenotype; D010766:Phosphorylation; D054648:Protein Phosphatase 2 / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D004268:DNA-Binding Proteins; C085242:ISF1 protein, S cerevisiae; C085976:MIG1 protein, S cerevisiae; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; D054648:Protein Phosphatase 2; C104343:SIT4 protein, S cerevisiae