Yeast Carbon Catabolite Repression
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TLDR
It is possible in certain cases to propose a partial model of the way in which the different elements involved in catabolite repression may be integrated, and preliminary evidence suggests that Snf1 is in a dephosphorylated state under these conditions.Abstract:
Glucose and related sugars repress the transcription of genes encoding enzymes required for the utilization of alternative carbon sources; some of these genes are also repressed by other sugars such as galactose, and the process is known as catabolite repression. The different sugars produce signals which modify the conformation of certain proteins that, in turn, directly or through a regulatory cascade affect the expression of the genes subject to catabolite repression. These genes are not all controlled by a single set of regulatory proteins, but there are different circuits of repression for different groups of genes. However, the protein kinase Snf1/Cat1 is shared by the various circuits and is therefore a central element in the regulatory process. Snf1 is not operative in the presence of glucose, and preliminary evidence suggests that Snf1 is in a dephosphorylated state under these conditions. However, the enzymes that phosphorylate and dephosphorylate Snf1 have not been identified, and it is not known how the presence of glucose may affect their activity. What has been established is that Snf1 remains active in mutants lacking either the proteins Grr1/Cat80 or Hxk2 or the Glc7 complex, which functions as a protein phosphatase. One of the main roles of Snf1 is to relieve repression by the Mig1 complex, but it is also required for the operation of transcription factors such as Adr1 and possibly other factors that are still unidentified. Although our knowledge of catabolite repression is still very incomplete, it is possible in certain cases to propose a partial model of the way in which the different elements involved in catabolite repression may be integrated.read more
Citations
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Journal ArticleDOI
Glucose regulation of Saccharomyces cerevisiae cell cycle genes.
TL;DR: A link between the rate of glycolysis and the expression of genes that are critical for passage through G1 is indicated, and addition of iodoacetate, an inhibitor of the glyceraldehyde-3-phosphate dehydrogenase step in yeast gly colysis, strongly downregulates the levels CLN3, BCK2, and CDC28 mRNAs.
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Active Snf1 protein kinase inhibits expression of the Saccharomyces cerevisiae HXT1 glucose transporter gene
Lidia Tomás-Cobos,Pascual Sanz +1 more
TL;DR: It is shown that Snf1 protein kinase participates actively in the inhibition of HXT1 expression, and that Rgt1 interacts physically with Ssn6, a major transcriptional repressor, to regulate negatively H XT1 expression when glucose is depleted.
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Structure-function analysis of yeast hexokinase: structural requirements for triggering cAMP signalling and catabolite repression.
TL;DR: It is concluded that the establishment of catabolite repression is dependent on the onset of the phosphoryl transfer reaction on hexokinase and is probably related to the stable formation of a transition intermediate and concomitant conformational changes within the enzyme.
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Disruption of the MIG1 gene enhances lipid biosynthesis in the oleaginous yeast Yarrowia lipolytica ACA-DC 50109.
TL;DR: Biosynthesis of C18:1 fatty acid in the disruptant M25 was greatly enhanced compared to that in the parent yeast, and transcript level of the MFE1 gene, one of the genes relevant to fatty acid degradation was reduced in the disrupting molecule.
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Pdc2 coordinates expression of the THI regulon in the yeast Saccharomyces cerevisiae
Dominik Mojzita,Stefan Hohmann +1 more
TL;DR: The analysis helps to further define the THI regulon and hence the spectrum of genes/proteins involved in the ThDP homeostasis and identify novel proteins putatively involved in thiamine and/or ThDP transport across the plasma and the mitochondrial membrane.
References
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