Open AccessGlucose uptake in Kluyveromyces lactis: role of the HGT1 gene in glucose transport
Author(s) -
Patrick Billard,
Sandrine Ménart,
Joël Blaisonneau,
Monique BolotinFukuhara,
Hiroshi Fukuhara,
Micheline WésolowskiLouvel
Publication year - 1996
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.178.20.5860-5866.1996
Subject(s) - kluyveromyces lactis , snf3 , biology , kluyveromyces , glucose transporter , biochemistry , glucose uptake , saccharomyces cerevisiae , yeast , hexokinase , mutant , nucleotide sugar , gene , lactose , nucleotide , metabolism , glycolysis , insulin , endocrinology
A gene for high-affinity glucose transport, HGT1, has been isolated from the lactose-assimilating yeast Kluyveromyces lactis. Disruption strains showed much-reduced uptake of glucose at low concentrations and growth was particularly affected in low-glucose medium. The HGT1 nucleotide sequence implies that it encodes a typical transmembrane protein with 12 hydrophobic domains and with 26 to 31% amino acid identity with the Hxtp family of glucose transport elements in Saccharomyces cerevisiae. Expression is constitutive (in contrast to RAG1, the major gene for low-affinity glucose uptake in K. lactis) and is controlled by several genes also known to affect expression of RAG1. These include RAG5 (which codes for the single hexokinase of K. lactis), which is required for HGT1 transcription, and RAG4, which has a negative effect. The double mutant deltahgt1deltarag1 showed further reduced glucose uptake but still grew quite well on 2% glucose and was not completely impaired even on 0.1% glucose.