The high-affinity glucose uptake system is not required for induction of the RAS-mediated cAMP signal by glucose in cells of the yeast Saccharomyces cerevisiae.
Addition of glucose or related fermentable sugars to yeast cells grown on non-fermentable carbon sources, triggers a RAS-protein mediated cAMP signal which induces a protein phosphorylation cascade. The high-affinity glucose uptake system in yeast cells is known to be glucose-repressible and only functional in strains containing at least one active kinase. In strains containing point or disruption mutations in the SNF3 gene, which codes for the high-affinity glucose carrier, the glucose-induced cAMP signal is still present. This indicates that the previously demonstrated requirement of a functional kinase for the induction of the cAMP signal, does not reflect requirement of high-affinity sugar transport. It also indicates that the unknown glucose-repressible protein in the induction sequence of the RAS-mediated cAMP signal is not the high-affinity sugar carrier.
Mbonyi
K
K
Laboratorium voor Cellulaire Biochemie, Katholieke Universiteit te Leuven, Belgium.
Thevelein
J M
JM
D000242:Cyclic AMP / Q000378:metabolism*; D004140:Dinitrophenols / Q000494:pharmacology; D005632:Fructose / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins / Q000502:physiology*; D009154:Mutation; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D016283:Proto-Oncogene Proteins p21(ras); D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D004140:Dinitrophenols; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D011518:Proto-Oncogene Proteins; D005632:Fructose; D000242:Cyclic AMP; D016283:Proto-Oncogene Proteins p21(ras); D005947:Glucose