Expression of the HXT1 low affinity glucose transporter requires the coordinated activities of the HOG and glucose signalling pathways.
Expression of the HXT1 gene, which encodes a low affinity glucose transporter in Saccharomyces cerevisiae, is regulated positively in response to glucose by the general glucose induction pathway, involving the Snf3/Rgt2 membrane glucose sensors, the SCF-Grr1 ubiquitination complex and the Rgt1 transcription factor. In this study we show that, in addition to the glucose signaling pathway, regulation of HXT1 expression also requires the HOG pathway. Deletion of components in the glucose signaling pathway or in the HOG pathway results in impaired HXT1 expression. Genetic analyses showed that, whereas the glucose signaling pathway regulates HXT1 through modulation of the Rgt1 transcription factor, the HOG pathway modulates HXT1 through regulation of the Sko1-Tup1-Ssn6 complex. Coordinated regulation of the two signaling pathways is required for expression of HXT1 by glucose and in response to osmostress.
Tomás-Cobos
Lidia
L
Instituto de Biomedicina de Valencia, Jaime Roig 11, 46010 Valencia, Spain.
Casadomé
Laura
L
Mas
Glòria
G
Sanz
Pascual
P
Posas
Francesc
F
D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D005822:Genetic Vectors; D005947:Glucose / Q000378:metabolism*; D051246:Glucose Transport Proteins, Facilitative; D015151:Immunoblotting; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D008954:Models, Biological; D009004:Monosaccharide Transport Proteins / Q000096:biosynthesis*; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000502:physiology*; D015398:Signal Transduction; D013997:Time Factors; D015533:Transcriptional Activation; D001616:beta-Galactosidase / Q000378:metabolism
D051246:Glucose Transport Proteins, Facilitative; C090594:HXT1 protein, S cerevisiae; D009004:Monosaccharide Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C088589:HOG1 protein, S cerevisiae; D020928:Mitogen-Activated Protein Kinases; D001616:beta-Galactosidase; D005947:Glucose