Glucose sensing and signaling in Saccharomyces cerevisiae through the Rgt2 glucose sensor and casein kinase I

Abstract

The yeast Saccharomyces cerevisiae senses glucose through two transmembrane glucose sensors, Snf3 and Rgt2. Extracellular glucose causes these sensors to generate an intracellular signal that induces expression of HXT genes encoding glucose transporters by inhibiting the function of Rgt1, a transcriptional repressor of HXT genes. We present the following evidence that suggests that the glucose sensors are coupled to the membrane-associated protein kinase casein kinase I (Yck1). (

Endocytosis and Vacuolar Degradation of the Yeast Cell Surface Glucose Sensors Rgt2 and Snf3

“…5C). High glucose-induced proteasomal degradation of Mth1 is triggered by glucose activation of the Rgt2 sensor (14,16). Western blot analysis showed that glucose-dependent Mth1 degradation occurs in cells expressing the wild type Rgt2 sensor but not the Rgt2 W529Y sensor (Fig.…”

Two Major Facilitator Superfamily Sugar Transporters from Trichoderma reesei and Their Roles in Induction of Cellulase Biosynthesis

“…A high degree of similarity between Stp1 and fungal glucose transporters was observed by means of the BLASTX algorithm. Phylogenetic analysis further revealed that Stp1 did not group with the well characterized cellobiose transporters from N. crassa (CTD1 and CTD2), but rather was closely related to some characterized glucose transporter proteins including HGT-1 from N. crassa (24), MstA from Aspergillus niger (25), as well as glucose sensors Rgt2 and Snf3 from S. cerevisiae (26) (Fig. 2).…”

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

“…It has been shown that Yck1/2-dependent Ssy5 prodomain phosphorylation precedes SCF Grr1 -dependent ubiquitylation (Abdel-Sater et al 2011). In other signaling pathways, Yck1/2-catalyzed phosphorylation has been shown to lead to Grr1-dependent polyubiquitylation and subsequent degradation of the modified substrates by the 26S proteasome (Moriya and Johnston 2004;Spielewoy et al 2004). Hence, the SPS sensor coordinates the activity of general signaling components to achieve a highly specific output (Omnus et al 2011) (Figure 11C).…”