1365-2958/asset/cover.gif?v=1&s=75254d9e3ae6a0f08085f34cc6e5bd65d8e3d52e "Molecular Microbiology")
Department of General and Marine Microbiology, Göteborg University, Medicinaregatan 9C, S-41390 Göteborg, Sweden.
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Evidence for trehalose-6-phosphate-dependent and -independent mechanisms in the control of sugar influx into yeast glycolysis
Article first published online: 6 OCT 2006
DOI: 10.1111/j.1365-2958.1996.tb02539.x
Additional Information
How to Cite
Hohmann, S., Bell, W., NevesA, M. J., Valckx, D. and Thevelein, J. M. (1996), Evidence for trehalose-6-phosphate-dependent and -independent mechanisms in the control of sugar influx into yeast glycolysis. Molecular Microbiology, 20: 981–991. doi: 10.1111/j.1365-2958.1996.tb02539.x
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Department of General and Marine Microbiology, Göteborg University, Medicinaregatan 9C, S-41390 Göteborg, Sweden.
Publication History
- Issue published online: 6 OCT 2006
- Article first published online: 6 OCT 2006
- Received 30 October, 1995; revised 27 February, 1996; accepted 29 February, 1996
- Abstract
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Summary
In the yeast Saccharomyces cerevisíae, trehalose-6-phosphate (tre-6-P) synthase encoded by GGS1/TPS1, is not only involved in the production of trehalose but also in restriction of sugar influx into glycolysis in an unknown fashion; it is therefore essential for growth on glucose or fructose. In this work, we have deleted the TPS2 gene encoding tre-6-P phosphatase in a strain which displays very low levels of Ggs1/Tps1, as a result of the presence of the byp1-3 allele of GGS1/TPS1. The byp1-3 tps2Δ double mutant showed elevated tre-6-P levels along with improved growth and ethanol production, although the estimated concentrations of glycolytic metabolites indicated excessive sugar influx. In the wild-type strain, the addition of glucose caused a rapid transient increase of tre-6-P. In tps2Δ mutant cells, which showed a high tre-6-P level before glucose addition, sugar influx into glycolysis appeared to be diminished. Furthermore, we have confirmed that tre-6-P inhibits the hexokinases in vitro. These data are consistent with restriction of sugar influx into glycolysis through inhibition of the hexokinases by tre-6-P during the switch to fermentative metabolism. During logarithmic growth on glucose the tre-6-P level in wild-type cells was lower than that of the byp1-3 tps2Δ. mutant. However, the latter strain arrested growth and ethanol production on glucose after about four generations. Hence, other mechanisms, which also depend on Ggs1/Tps1, appear to control sugar influx during growth on glucose. In addition, we provide evidence that the requirement for Ggs1/Tps1 for sporulation may be unrelated to its involvement in trehalose metabolism or in the system controlling glycolysis.