title: TOR kinase pathway and 14-3-3 proteins regulate glucose-induced expression of HXT1, a yeast low-affinity glucose transporter.
abstract: Expression of HXT1, a gene encoding a Saccharomyces cerevisiae low-affinity glucose transporter, is regulated by glucose availability, being activated in the presence of glucose and inhibited when the levels of the sugar are scarce. In this study we show that 14-3-3 proteins are involved in the regulation of the expression of HXT1 by glucose. We also demonstrate that 14-3-3 proteins, in complex with Reg1, a regulatory subunit of Glc7 protein phosphatase, interact physically with Grr1 (a component of the SCF-Grr1 ubiquitination complex), a key player in the process of HXT1 induction by glucose. In addition, we show that the TOR kinase pathway participates actively in the induction of HXT1 expression by glucose. Inhibition of the TOR kinase pathway by rapamycin treatment abolishes HXT1 glucose induction. A possible involvement of PP2A protein phosphatase complex, through the Cdc55 B-subunit, in the glucose induction of HXT1 is also discussed.
authors.affiliation: Instituto de Biomedicina de Valencia (CSIC), Jaime Roig 11, 46010-Valencia, Spain.
authors.forename: Lidia
authors.initials: L
authors.lastname: Tomás-Cobos
authors.forename: Rosa
authors.initials: R
authors.lastname: Viana
authors.forename: Pascual
authors.initials: P
authors.lastname: Sanz
mesh_terms: D048948:14-3-3 Proteins / Q000378:metabolism*; D001692:Biological Transport; D018797:Cell Cycle Proteins / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044783:F-Box Proteins; D005947:Glucose / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative; D015151:Immunoblotting; D008840:Microfilament Proteins / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D054648:Protein Phosphatase 2; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D020123:Sirolimus / Q000494:pharmacology; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
chemical_list: D048948:14-3-3 Proteins; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; D004791:Enzyme Inhibitors; D044783:F-Box Proteins; D005947:Glucose; D051246:Glucose Transport Proteins, Facilitative; D008840:Microfilament Proteins; D009004:Monosaccharide Transport Proteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D017853:Phosphotransferases (Alcohol Group Acceptor); D054648:Protein Phosphatase 2; D029701:Saccharomyces cerevisiae Proteins; D020123:Sirolimus; D044767:Ubiquitin-Protein Ligases; C071246:CDC55 protein, S cerevisiae; C090594:HXT1 protein, S cerevisiae; C115237:actin interacting protein 1; C071032:GRR1 protein, S cerevisiae; C083324:TOR1 protein, S cerevisiae