The Snf1 protein kinase controls the induction of genes of the iron uptake pathway at the diauxic shift in Saccharomyces cerevisiae.
In Saccharomyces cerevisiae the transition between the fermentative and the oxidative metabolism, called the diauxic shift, is associated with major changes in gene expression. In this study, we characterized a novel family of five genes whose expression is induced during the diauxic shift. These genes, FET3, FTR1, TIS11, SIT1, and FIT2, are involved in the iron uptake pathway. We showed that their induction at the diauxic shift is positively controlled by the Snf1/Snf4 kinase pathway. The transcriptional factor Aft1p, which is known to control their induction in response to iron limitation, is also required for their induction during the diauxic shift. The increase of the extracellular iron concentration does not affect this induction, indicating that glucose exhaustion by itself would be the signal. The possibility that the Snf1/Snf4 pathway was also involved in the induction of the same set of genes in response to iron starvation was considered. We demonstrate here that this is not the case. Thus, the two signals, glucose exhaustion and iron starvation, use two independent pathways to activate the same set of genes through the Aft1p transcriptional factor.
Haurie
Valérie
V
Institut de Biochimie et Génétique Cellulaires, UMR 5095, 33077 Bordeaux Cedex, France.
Boucherie
Helian
H
Sagliocco
Francis
F
D015152:Blotting, Northern; D027682:Cation Transport Proteins / Q000235:genetics; D002570:Ceruloplasmin / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics; D015151:Immunoblotting; D007501:Iron / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics; D009693:Nucleic Acid Hybridization; D016366:Open Reading Frames; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D051816:Tristetraprolin
C090297:AFT1 protein, S cerevisiae; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; C445318:FIT2 protein, S cerevisiae; C098723:FTR1 protein, S cerevisiae; D006023:Glycoproteins; D026901:Membrane Transport Proteins; C118510:SIT1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C091790:TIS11 protein, S cerevisiae; D014157:Transcription Factors; D051816:Tristetraprolin; D007501:Iron; D002570:Ceruloplasmin; C085513:FET3 protein, S cerevisiae; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; D005947:Glucose