Biochemical Evidence for Glucose-Independent Induction of HXT Expression in Saccharomyces cerevisiae
The yeast glucose sensors Rgt2 and Snf3 generate a signal in response to glucose that leads to degradation of Mth1 and Std1, thereby relieving repression of Rgt1-repressed genes such as the glucose transporter genes (HXT). Mth1 and Std1 are degraded via the Yck1/2 kinase-SCFGrr1-26S proteasome pathway triggered by the glucose sensors. Here, we show that RGT2-1 promotes ubiquitination and subsequent degradation of Mth1 and Std1 regardless of the presence of glucose. Site-specific mutagenesis reveals that the conserved lysine residues of Mth1 and Std1 might serve as attachment sites for ubiquitin, and that the potential casein kinase (Yck1/2) sites of serine phosphorylation might control their ubiquitination. Finally, we show that active Snf1 protein kinase in high glucose prevents degradation of Mth1 and Std1.
(2007). Biochemical Evidence for Glucose-Independent Induction of HXT Expression in Saccharomyces cerevisiae. FEBS Letters, 581(17), 3230-3234.
Available at: https://aquila.usm.edu/fac_pubs/8499