The fenpropimorph resistance gene FEN2 from Saccharomyces cerevisiae encodes a plasma membrane H+-pantothenate symporter.
The product of the FEN2 gene of Saccharomyces cerevisiae has previously been described as a protein conferring sensitivity to the antifungal agent fenpropimorph. Fen2p was postulated to act as a common regulator of carbon and nitrogen catabolite repression and of amino acid and ergosterol biosynthesis. In this paper, we present experimental evidence characterizing Fen2p as a plasma membrane-localized transporter for the vitamin pantothenate. The high affinity transport system (Km = 3.5 microM) is sensitive to uncouplers, suggesting a H+-pantothenate cotransport. Pantothenate transport rates in yeast are modulated by extracellular pantothenate, being maximal at low pantothenate concentrations. It is demonstrated that beta-alanine can suppress the growth defect of FEN2 wild-type and fen2 mutant cells on pantothenate-free medium. Evidence is presented that beta-alanine is transported by the general amino acid permease Gap1p. The relation among pantothenate transport, nitrogen catabolite repression, and sensitivity to the antifungal agent fenpropimorph is discussed.
Stolz
J
J
Lehrstuhl Botanik II, Molekulare Pflanzenphysiologie, Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany.
Sauer
N
N
D000595:Amino Acid Sequence; D001692:Biological Transport / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004352:Drug Resistance, Microbial / Q000235:genetics; D005659:Fungicides, Industrial / Q000494:pharmacology*; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009025:Morpholines / Q000494:pharmacology*; D010205:Pantothenic Acid / Q000378:metabolism*; D010641:Phenotype; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D027981:Symporters
D002352:Carrier Proteins; C436246:FEN2 protein, S cerevisiae; D005659:Fungicides, Industrial; D008565:Membrane Proteins; D009025:Morpholines; D029701:Saccharomyces cerevisiae Proteins; D027981:Symporters; C119982:pantothenate transporter; D010205:Pantothenic Acid; C050435:fenpropimorph