Glucose sensing and signaling by two glucose receptors in the yeast Saccharomyces cerevisiae.
How eukaryotic cells sense availability of glucose, their preferred carbon and energy source, is an important, unsolved problem. Bakers' yeast (Saccharomyces cerevisiae) uses two glucose transporter homologs, Snf3 and Rgt2, as glucose sensors that generate a signal for induction of expression of genes encoding hexose transporters (HXT genes). We present evidence that these proteins generate an intracellular glucose signal without transporting glucose. The Snf3 and Rgt2 glucose sensors contain unusually long C-terminal tails that are predicted to be in the cytoplasm. These tails appear to be the signaling domains of Snf3 and Rgt2 because they are necessary for glucose signaling by Snf3 and Rgt2, and transplantation of the C-terminal tail of Snf3 onto the Hxt1 and Hxt2 glucose transporters converts them into glucose sensors that can generate a signal for glucose-induced HXT gene expression. These results support the idea that yeast senses glucose using two modified glucose transporters that serve as glucose receptors.
Ozcan
S
S
Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA.
Dover
J
J
Johnston
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D016384:Consensus Sequence; D017931:DNA Primers; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D005947:Glucose / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D015398:Signal Transduction; D001616:beta-Galactosidase / Q000096:biosynthesis
D017931:DNA Primers; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; C112512:RGT2 protein, S cerevisiae; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C104463:SNF3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C027786:glucose receptor; D001616:beta-Galactosidase; D005947:Glucose