Fructose‐1,6‐bisphosphatase of the yeast <i>Kluyveromyces lactis</i>

Zaror, Isabel; Marcus, Frank I.; Moyer, Donna L.; Tung, J. S.; Shuster, Jeffrey R.

doi:10.1111/j.1432-1033.1993.tb17650.x

Cited by 17 publications

(10 citation statements)

References 54 publications

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“…In particular, the amount of the KlSDH1 mRNA from ethanol and glycerol cultures was very similar to that of cells grown in 1 and 7% glucose, indicating that the gene was not sensitive to carbon catabolite repression. These results are in agreement with the general observation that respiratory genes of K. lactis escape transcriptional repression during growth on glucose (26,35,36,53). No KlSDH1 mRNA could be detected in the Klsdh1⌬ strain grown on different concentrations of glucose or lactate (lanes 8, 9, and 10).…”

Section: Resultssupporting

confidence: 91%

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

et al. 2004

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We have isolated a Kluyveromyces lactis mutant unable to grow on all respiratory carbon sources with the exception of lactate. Functional complementation of this mutant led to the isolation of KlSDH1, the gene encoding the flavoprotein subunit of the succinate dehydrogenase (SDH) complex, which is essential for the aerobic utilization of carbon sources. Despite the high sequence conservation of the SDH genes in Saccharomyces cerevisiae and K. lactis, they do not have the same relevance in the metabolism of the two yeasts. In fact, unlike SDH1, KlSDH1 was highly expressed under both fermentative and nonfermentative conditions. In addition to this, but in contrast with S. cerevisiae, K. lactis strains lacking KlSDH1 were still able to grow in the presence of lactate. In these mutants, oxygen consumption was one-eighth that of the wild type in the presence of lactate and was normal with glucose and ethanol, indicating that the respiratory chain was fully functional. Northern analysis suggested that alternative pathway(s), which involves pyruvate decarboxylase and the glyoxylate cycle, could overcome the absence of SDH and allow (i) lactate utilization and (ii) the accumulation of succinate instead of ethanol during growth on glucose.Succinate dehydrogenase (SDH) is a component of complex II of the respiratory chain that catalyses the oxidation of succinate to fumarate in the Krebs cycle and feeds electrons to the ubiquinone pool. The complex, which is highly conserved through evolution, is located in the inner mitochondrial membrane and consists of two catalytic and two structural subunits, all encoded by nuclear genes (38). In Saccharomyces cerevisiae, the four genes (SDH1 to SDH4) coding for SDH have been isolated and characterized (26,27,45,47). The flavoprotein subunit (11, 42) responsible for the oxidation of succinate to fumarate is encoded by two paralogous genes, SDH1 and SDH1b, although only SDH1 is necessary for growth on respiratory carbon sources (11). SDH2 codes for the iron-protein subunit (31) that contains three different iron-sulfur centers (22) and, together with the protein Sdh1p, constitutes the catalytic core of the SDH complex, which conveys electrons from the covalently attached flavin adenine dinucleotide (FAD) of Sdh1p first to the iron-sulfur centers and then to ubiquinone. SDH3 and SDH4 code for two small hydrophobic peptides, which anchor the complex to the inner mitochondrial membrane (10, 15). In humans, the mutations in the SDH genes have been associated to several mitochondrial-related pathologies suggesting, beside the enzymatic activity of the complex in the Krebs cycle, its involvement in superoxide handling (39,43).In S. cerevisiae, the expression of the SDH genes is repressed by glucose and derepressed on respiratory carbon sources (31, 45), and the loss of SDH functions results in the inability of cells to grow on any respiratory carbon sources (12,47).In this paper we report the isolation of the KlSDH1 gene (EMBL accession number AJ555233) encoding the Kluyveromyces lactis fla...

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Section: Resultssupporting

confidence: 91%

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

et al. 2004

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“…5) revealed that the level of KlFBP1-speci®c mRNA in glucosegrown wild-type cells is reduced compared to that in glycerol-and ethanol-grown cells. The repression observed in strain JA6 is stronger than that described previously for strain 2UV21 (Zaror et al 1993). Similarly, the amount of KlPCK1 mRNA expressed in glucose medium is lower than that in ethanol.…”

Section: Resultscontrasting

confidence: 68%

Differences in regulation of yeast gluconeogenesis revealed by Cat8p-independent activation of PCK1 and FBP1 genes in Kluyveromyces lactis

et al. 2000

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The yeast Kluyveromyces lactis is can utilise a wide range of non-fermentable carbon compounds as sole sources of carbon and energy, and differs from Saccharomyces cerevisiae in being able to carry out oxidative and fermentative metabolism simultaneously. In S. cerevisiae, growth on all non-fermentable carbon sources requires Cat8p, a transcriptional activator that controls the expression of gluconeogenic and glyoxylate cycle genes via CSREs (Carbon Source Responsive Elements). The down-regulation of Cat8p by fermentable carbon sources is the primary factor responsible for the tight repression of gluconeogenesis by glucose in S. cerevisiae. To analyse the regulation of gluconeogenesis in K. lactis, we have cloned and characterised the K. lactis homologue of CAT8 (KlCAT8). The gene was isolated by multicopy suppression of a fog2/klsnf1 mutation, indicating a similar epistatic relationship between KlSNF1 and KlCAT8 as in the case of the S. cerevisiae homologues. KlCAT8 encodes a protein of 1445 amino acids that is 40% identical to ScCat8p. The most highly conserved block is the putative Zn(II)2Cys6 DNA-binding domain, but additional conserved regions shared with members of the zinc-cluster family from Aspergillus define a subfamily of Cat8p-related proteins. KlCAT8 complements the growth defect of a Sccat8 mutant on non-fermentable carbon sources. In K. lactis, deletion of KlCAT8 severely impairs growth on ethanol, acetate and lactate, but not on glycerol. Derepression of enzymes of the glyoxylate cycle--malate synthase and particularly isocitrate lyase--was impaired in a Klcat8 mutant, whereas Northern analysis revealed that derepression of KlFBP1 and KlPCK1 does not require KlCat8p. Taken together, our results indicate that in K. lactis gluconeogenesis is not co-regulated with the glyoxylate cycle, and only the latter is controlled by KlCat8p.

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“…The protein from K. lactis contains a short amino acid insert sequence near the binding site of the allosteric inhibitor AMP absent in the S. cerevisiae protein. This amino acid stretch seems to be responsible for the lower sensitivity to AMP inhibition of this enzyme with respect to that of S. cerevisiae [237]. The expression of the gene is usually repressed in the presence of glucose, although differences in the degree of repression are observed among species.…”

Section: Gluconeogenesismentioning

confidence: 93%

“…This reaction is the terminal step of gluconeogenesis and therefore the corresponding enzyme is required for metabolism of every non‐sugar carbon source. The gene encoding this enzyme has been isolated from S. pombe [236] and from K. lactis [237] and the enzyme has also been purified from C. utilis [238]. The protein from K. lactis contains a short amino acid insert sequence near the binding site of the allosteric inhibitor AMP absent in the S. cerevisiae protein.…”

Section: Gluconeogenesismentioning

confidence: 99%

Carbohydrate and energy-yielding metabolism in non-conventional yeasts: Figure 1

et al. 2000

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Sugars are excellent carbon sources for all yeasts. Since a vast amount of information is available on the components of the pathways of sugar utilization in Saccharomyces cerevisiae it has been tacitly assumed that other yeasts use sugars in the same way. However, although the pathways of sugar utilization follow the same theme in all yeasts, important biochemical and genetic variations on it exist. Basically, in most non-conventional yeasts, in contrast to S. cerevisiae, respiration in the presence of oxygen is prominent for the use of sugars. This review provides comparative information on the different steps of the fundamental pathways of sugar utilization in non-conventional yeasts: glycolysis, fermentation, tricarboxylic acid cycle, pentose phosphate pathway and respiration. We consider also gluconeogenesis and, briefly, catabolite repression. We have centered our attention in the genera Kluyveromyces, Candida, Pichia, Yarrowia and Schizosaccharomyces, although occasional reference to other genera is made. The review shows that basic knowledge is missing on many components of these pathways and also that studies on regulation of critical steps are scarce. Information on these points would be important to generate genetically engineered yeast strains for certain industrial uses.

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Fructose‐1,6‐bisphosphatase of the yeast Kluyveromyces lactis

Cited by 17 publications

References 54 publications

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

The Deletion of the Succinate Dehydrogenase Gene KlSDH1 in Kluyveromyces lactis Does Not Lead to Respiratory Deficiency

Differences in regulation of yeast gluconeogenesis revealed by Cat8p-independent activation of PCK1 and FBP1 genes in Kluyveromyces lactis

Carbohydrate and energy-yielding metabolism in non-conventional yeasts: Figure 1

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