The glucose signaling network in yeast

Abstract

Background Most cells possess a sophisticated mechanism for sensing glucose and responsing to it appropriately. Glucose sensing and signaling in the budding yeast Saccharomyces cerevisiae represents an important paradigm for understanding how extracellular signals lead to changes in the gene expression program in eukaryotes. Scope of review This review focuses on the yeast glucose sensing and signaling pathways that operate in a highly regulated and cooperative manner to bring about glucose-induction of HXT gene expression. Major conclusions The yeast cells possess a family of glucose transporters (HXTs), with different kinetic properties. They employ three major glucose signaling pathways— Rgt2/Snf3, AMPK, and cAMP-PKA—to express only those transporters best suited for the amounts of glucose available. We discuss the current understanding of how these pathways are integrated into a regulatory network to ensure efficient uptake and utilization of glucose. General significance Elucidating the role of multiple glucose signals and pathways involved in glucose uptake and metabolism in yeast may reveal the molecular basis of glucose homeostasis in humans, especially under pathological conditions, such as hyperglycemia in diabetics and the elevated rate of glycolysis observed in many solid tumors.

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

“…Addition of glucose to glucosedepleted cells induces degradation of Mth1 (14 -18) and consequent phosphorylation of Rgt1 by PKA, leading to Rgt1 dissociation from DNA and thus to HXT gene expression (11,12). Hence, multiple mechanisms are involved for fine-tuned regulation of HXT gene expression (19).…”

Proteome and metabolome profiling of wild-type and YCA1 -knock-out yeast cells during acetic acid-induced programmed cell death

“…5). We could not detect intermediate metabolites of the Krebs cycle probably due to the unique glucose repression system that drastically suppresses respiration independently of oxygen availability in yeast growing in the presence of glucose as a sole carbon source [32].…”

Glycolysis Controls Plasma Membrane Glucose Sensors To Promote Glucose Signaling in Yeasts

“…The effect of the extracellular glucose concentration on glucose signaling has been widely studied in both K. lactis (11) and S. cerevisiae (1,12). However, intracellular glucose and particularly its metabolism through glycolysis appear to exert regulation of glucose transport independently of the presence of extracellular hexose.…”

“…1B) (1,12). At least 17 hexose transporter homologs (Hxts) exist in S. cerevisiae, with Hxt1 being the Rag1 functional homolog (13).…”