Rgt1inYeastGlucoseInductionPathway

Yeast sense glucose in their environment and alter gene expression to match their nutritional needs. In a glucose-rich environment, glycolysis is activated, glucose transport is increased and gluconeogenesis repressed to use glucose to make energy. In a glucose-poor environment these processes are regulated in the opposite direction. Rgt1 is a yeast transcription factor that helps to regulate glucose metabolism, responding to glucose levels by regulating transcription of genes like hexose transporters (HXT1 and HXT2) involved in glucose metabolism. Rgt1 does not itself directly sense glucose levels but is regulated by Rgt2 and Snf3 acting through the SCF ubiquitin ligase complex. The SCF complex, including Grr1 and Skp1, targets Rgt1 and other proteins for degradation through ligation with ubiquitin. The activity of the SCF complex and its ability to degrade Rgt1 are regulated by Rgt2 and Snf3, glucose transporters that also act as glucose sensors on the cell surface to regulate the activity of the SCF complex and Rgt1.

Contributor: Glenn Croston, PhD

REFERENCES: Ozcan S, Johnston M. Function and regulation of yeast hexose transporters. Microbiol Mol Biol Rev 1999 Sep;63(3):554-69