title: Hexokinase regulates kinetics of glucose transport and expression of genes encoding hexose transporters in Saccharomyces cerevisiae.
abstract: Glucose transport kinetics and mRNA levels of different glucose transporters were determined in Saccharomyces cerevisiae strains expressing different sugar kinases. During exponential growth on glucose, a hxk2 null strain exhibited high-affinity hexose transport associated with an elevated transcription of the genes HXT2 and HXT7, encoding high-affinity transporters, and a diminished expression of the HXT1 and HXT3 genes, encoding low-affinity transporters. Deletion of HXT7 revealed that the high-affinity component is mostly due to HXT7; however, a previously unidentified very-high-affinity component (K(m) = 0.19 mM) appeared to be due to other factors. Expression of genes encoding hexokinases from Schizosaccharomyces pombe or Yarrowia lipolytica in a hxk1 hxk2 glk1 strain prevented derepression of the high-affinity transport system at high concentrations of glucose.
authors.affiliation: Instituto de Investigaciones Biomédicas Alberto Sols, 28029 Madrid, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Petit
authors.forename: J A
authors.initials: JA
authors.lastname: Diderich
authors.forename: A L
authors.initials: AL
authors.lastname: Kruckeberg
authors.forename: C
authors.initials: C
authors.lastname: Gancedo
authors.forename: K
authors.initials: K
authors.lastname: Van Dam
mesh_terms: D001692:Biological Transport; D005656:Fungal Proteins / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism*; D051246:Glucose Transport Proteins, Facilitative; D006593:Hexokinase / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D005656:Fungal Proteins; D051246:Glucose Transport Proteins, Facilitative; C090594:HXT1 protein, S cerevisiae; C084498:HXT2 protein, S cerevisiae; C090595:HXT3 protein, S cerevisiae; C090593:HXT4 protein, S cerevisiae; C095258:HXT7 protein, S cerevisiae; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D006593:Hexokinase; D005947:Glucose