Carboxylic acids permeases in yeast: two genes in Kluyveromyces lactis.
Two new genes KlJEN1 and KlJEN2 were identified in Kluyveromyces lactis. The deduced structure of their products is typical of membrane-bound carriers and displays high similarity to Jen1p, the monocarboxylate permease of Saccharomyces cerevisiae. Both KlJEN1 and KlJEN2 are under the control of glucose repression mediated by FOG1 and FOG2, corresponding to S. cerevisiae GAL83 and SNF1 respectively, and KlCAT8, proteins involved in glucose signalling cascade in K. lactis. KlJEN1, but not KlJEN2, is induced by lactate. KlJEN2 in contrast is expressed at high level in ethanol and succinate. The physiological characterization of null mutants showed that KlJEN1 is the functional homologue of ScJEN1, whereas KlJEN2 encodes a dicarboxylic acids transporter. In fact, KlJen1p [transporter classification (TC) number: 2.A.1.12.2.] is required for lactate uptake and therefore for growth on lactate. KlJen2p is required for succinate transport, as demonstrated by succinate uptake experiments and by inability of Kljen2 mutant to grow on succinate. This carrier appears to transport also malate and fumarate because the Kljen2 mutant cannot grow on these substrates and the succinate uptake is competed by these carboxylic acids. We conclude that KlJEN2 is the first yeast gene shown to encode a dicarboxylic acids permease.
Lodi
Tiziana
T
Dipartimento di Genetica Antropologia Evoluzione, University of Parma, Viale delle Scienze 11/A, 43100 Parma, Italy. tiziana.lodi@unipr.it
Fontanesi
Flavia
F
Ferrero
Iliana
I
Donnini
Claudia
C
D015152:Blotting, Northern; D002264:Carboxylic Acids / Q000378:metabolism; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D029382:Dicarboxylic Acid Transporters / Q000235:genetics* / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D000431:Ethanol / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D007716:Kluyveromyces / Q000201:enzymology / Q000235:genetics*; D045022:Lactate Dehydrogenases / Q000096:biosynthesis; D007773:Lactates / Q000494:pharmacology; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019998:Racemases and Epimerases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D017422:Sequence Analysis, DNA; D013386:Succinates / Q000494:pharmacology; D014170:Transformation, Genetic
D002264:Carboxylic Acids; D004271:DNA, Fungal; D029382:Dicarboxylic Acid Transporters; D005656:Fungal Proteins; D007773:Lactates; D027501:Monocarboxylic Acid Transporters; D012333:RNA, Messenger; D013386:Succinates; D000431:Ethanol; D045022:Lactate Dehydrogenases; D019998:Racemases and Epimerases; C021498:lactate racemase; D005947:Glucose