Eukaryotic Cell doi:10.1128/EC.00169-08
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.
The gluconeogenic enzyme fructose-1, 6-bisphosphatase is dispensable for growth of the yeast Yarrowia lipolytica in gluconeogenic substrates
Raquel Jardón,
Carlos Gancedo,
and
Carmen-Lisset Flores*
Department of Metabolism and Cell Signaling, Instituto de Investigaciones Biomédicas "Alberto Sols" CSIC-UAM, C/Arturo Duperier 4, E-28029 Madrid, Spain
* To whom correspondence should be addressed. Email:
clflores{at}iib.uam.es.
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Abstract |
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The genes encoding gluconeogenic enzymes in the non-conventional yeast Yarrowia lipolytica were found to be differentially regulated. Expression of YlFBP1 encoding the key enzyme fructose-1, 6-bisphosphatase was not repressed by glucose in contrast with the situation in other yeasts; however this sugar markedly repressed the expression of YlPCK1, encoding phosphoenolpyruvate carboxykinase, and YlICL1 encoding isocitrate lyase. We constructed Y. lipolytica strains with two different disrupted versions of YlFBP1 and found that they grew much slower than the wild type in gluconeogenic carbon sources but growth was not abolished as happens in most micro organisms. We attribute this growth to the existence of an alternative phosphatase with a high Km, 2.3 mM, for fructose-1, 6-bisphosphate. The gene YlFBP1 restored fructose-1, 6-bisphosphatase activity and growth in gluconeogenic carbon sources to a Saccharomyces cerevisiae fbp1 mutant but introduction of the FBP1 gene from S. cerevisiae in the Ylfbp1 mutant did not produce fructose-1, 6-bisphosphatase activity or growth complementation. Subcellular fractionation revealed the presence of fructose-1, 6-bisphosphatase both in the cytoplasm and in the nucleus.
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