SUT2 is a novel multicopy suppressor of low activity of the cAMP/protein kinase A pathway in yeast

Eur J Biochem. 2004 Apr;271(7):1284-91. doi: 10.1111/j.1432-1033.2004.04034.x.


SUT2 was found in a screen for multicopy suppressors of the synthetic slow growth phenotype of a Deltaras2Deltagpa2 double deletion mutant. It failed, however, to cure the lethal phenotype of a Deltaras1Deltaras2 mutant suggesting that it acts upstream of Ras or in a parallel pathway. By testing cAMP-dependent reactions including the accumulation of storage carbohydrates, pseudohyphal differentiation, entry of meiosis as well as the measurement of FLO11 reporter activity we show that Sut2p modulates the activity of protein kinase A (PKA). Additionally, we demonstrate that cellular levels of Ras2p are affected by Sut2p and that Sut2-GFPp accumulates significantly in the nucleus. Based on the observed influence of high SUT2 gene dosage on PKA activity as well as Sut2p's homology to the presumptive transcription factor Sut1p, we suggest that Sut2p contributes to regulation of PKA activity at the level of transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Division
  • Cell Nucleus / metabolism
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Fungal Proteins / physiology*
  • Gene Dosage
  • Genes, Reporter
  • Genetic Complementation Test
  • Glycogen / metabolism
  • Green Fluorescent Proteins
  • Immunoblotting
  • Luminescent Proteins / metabolism
  • MAP Kinase Signaling System
  • Microscopy, Fluorescence
  • Monosaccharide Transport Proteins / physiology*
  • Mutation
  • Open Reading Frames
  • Phenotype
  • Plasmids / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Saccharomyces cerevisiae / metabolism
  • Time Factors
  • Transcription, Genetic
  • Trehalose / metabolism
  • beta-Galactosidase / metabolism
  • ras Proteins / metabolism


  • Fungal Proteins
  • Luminescent Proteins
  • Monosaccharide Transport Proteins
  • Recombinant Fusion Proteins
  • SUT2 protein, Pichia stipitis
  • Green Fluorescent Proteins
  • Glycogen
  • Trehalose
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • beta-Galactosidase
  • ras Proteins