Identification of the Plasma Membrane H+-Biotin Symporter of Saccharomyces cerevisiae by Rescue of a Fatty Acid-auxotrophic Mutant

Stolz, Jürgen; Hoja, Ursula; Meier, Sandra; Sauer, Norbert; Schweizer, Eckhart

doi:10.1074/jbc.274.26.18741

Cited by 54 publications

(81 citation statements)

References 45 publications

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“…We demonstrated before that protonophores cause a severe reduction in the activity of known proton-vitamin symporters (22,40,43). We repeated some of these experiments and found that biotin uptake, for example, is reduced to 25% of controls by the addition of 0.1 mM carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (data not shown).…”

Section: The Function Of Mch5 Is Unique Within the Mch Gene Familymchmentioning

confidence: 78%

The Monocarboxylate Transporter Homolog Mch5p Catalyzes Riboflavin (Vitamin B2) Uptake in Saccharomyces cerevisiae

Reihl¹,

Stolz

2005

Journal of Biological Chemistry

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Riboflavin is a water-soluble vitamin (vitamin B 2 ) required for the production of the flavin cofactors FMN and FAD. Mammals are unable to synthesize riboflavin and need a dietary supply of the vitamin. Riboflavin transport proteins operating in the plasma membrane thus have an important role in the absorption of the vitamin. However, their sequences remained elusive, and not a single eukaryotic riboflavin transporter is known to date. Here we used a genetic approach to isolate MCH5, a Saccharomyces cerevisiae gene with homology to mammalian monocarboxylate transporters, and characterize the protein as a plasma membrane transporter for riboflavin. This conclusion is based on the suppression of riboflavin biosynthetic mutants (rib mutants) by overexpression of MCH5 and by synthetic growth defects caused by deletion of MCH5 in rib mutants. We also show that cellular processes in multiple compartments are affected by deletion of MCH5 and localize the protein to the plasma membrane. Transport experiments in S. cerevisiae and Schizosaccharomyces pombe cells demonstrate that Mch5p is a high affinity transporter (K m ‫؍‬ 17 M) with a pH optimum at pH 7.5. Riboflavin uptake is not inhibited by protonophores, does not require metabolic energy, and operates by a facilitated diffusion mechanism. The expression of MCH5 is regulated by the cellular riboflavin content. This indicates that S. cerevisiae has a mechanism to sense riboflavin and avert riboflavin deficiency by increasing the expression of the plasma membrane transporter MCH5. Moreover, the other members of the MCH gene family appear to have unrelated functions.The proteins that require FMN or FAD as cofactors are termed flavoproteins. Mostly, they contain noncovalently bound flavin cofactors and are specific for either FAD or FMN. Some of them contain auxiliary groups such as pteridin, heme, iron-sulfur centers, molybdenum, or other metal ions or contain disulfides in their active site. Flavoproteins are involved in a wide range of biochemical reactions. They play a pivotal role in the dehydrogenation of metabolites in one-and two-electron transfer reactions from and to redox centers, in the activation of oxygen for oxidation, and in hydroxylation reactions (1).The flavin cofactor FMN is produced from riboflavin by the action of riboflavin kinase. FAD derives from FMN and ATP, a reaction catalyzed by FAD synthetase. Riboflavin is a vitamin (vitamin B 2 ) for mammals and many other organisms. Thus, dietary riboflavin has to be taken up from the gut and then provided to every single cell in a multicellular organism. Plasma membrane riboflavin transporters are thought to play an important role in the distribution of riboflavin. However, their existence in many cell types up to now has only been demonstrated biochemically (reviewed in Ref. 2). Whereas passive uptake of riboflavin is commonly observed in riboflavin-sufficient conditions, riboflavin uptake at low concentrations follows saturation kinetics and displays high affinity for the substrate (K m ϭ 1 nM to 1 M ...

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Section: The Function Of Mch5 Is Unique Within the Mch Gene Familymchmentioning

confidence: 78%

The Monocarboxylate Transporter Homolog Mch5p Catalyzes Riboflavin (Vitamin B2) Uptake in Saccharomyces cerevisiae

Reihl¹,

Stolz

2005

Journal of Biological Chemistry

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“…Biotin is taken up by VHT1, a plasma membrane biotin transporter (Stolz et al 1999). Many prokaryotes are capable of synthesizing biotin, as are plants and some fungi.…”

Section: B Iotin (Vitamin H) Is An Essential Vitamin Inmentioning

confidence: 99%

The Reacquisition of Biotin Prototrophy in Saccharomyces cerevisiae Involved Horizontal Gene Transfer, Gene Duplication and Gene Clustering

2007

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The synthesis of biotin, a vitamin required for many carboxylation reactions, is a variable trait in Saccharomyces cerevisiae. Many S. cerevisiae strains, including common laboratory strains, contain only a partial biotin synthesis pathway. We here report the identification of the first step necessary for the biotin synthesis pathway in S. cerevisiae. The biotin auxotroph strain S288c was able to grow on media lacking biotin when BIO1 and the known biotin synthesis gene BIO6 were introduced together on a plasmid vector. BIO1 is a paralog of YJR154W, a gene of unknown function and adjacent to BIO6. The nature of BIO1 illuminates the remarkable evolutionary history of the biotin biosynthesis pathway in S. cerevisiae. This pathway appears to have been lost in an ancestor of S. cerevisiae and subsequently rebuilt by a combination of horizontal gene transfer and gene duplication followed by neofunctionalization. Unusually, for S. cerevisiae, most of the genes required for biotin synthesis in S. cerevisiae are grouped in two subtelomeric gene clusters. The BIO1-BIO6 functional cluster is an example of a cluster of genes of ''dispensable function,'' one of the few categories of genes in S. cerevisiae that are positionally clustered.

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“…Mutation of the glycosylation sites at N138 and N489 reduced the V max of the importer activity, but did not affect the affinity for biotin, implying a key role of the sugar moieties in the activity of the transporter [68]. Likewise, posttranslational phosphorylation of SMVT is utilized to regulate SMVT activity [69]. This was demonstrated in colorectal adenocarcinoma cells where the addition of protein kinase C activators reduced uptake of biotin whereas the presence of kinase inhibitors stimulated its uptake [60].…”

Section: Mammalian Sodium -Dependent Multivitamin Transporter (Smvt1)mentioning

confidence: 69%

“…MCT1 has also been proposed as an alternative mammalian biotin transporter in cells of the lymphoid lineage [71], despite these cells also expressing a functional SMVT [69]. In mammalian colonic luminal membrane vesicles, MCT1 acts as the main protein that facilitates translocation of bicarbonate ions from the colonic lumen into colonocytes [72].…”

Section: Mammalian Monocarboxylate Transporter (Mct)mentioning

confidence: 99%

Mechanisms of Biotin Transport

Polyak¹

2015

Biochem Anal Biochem

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Identification of the Plasma Membrane H+-Biotin Symporter of Saccharomyces cerevisiae by Rescue of a Fatty Acid-auxotrophic Mutant

Cited by 54 publications

References 45 publications

The Monocarboxylate Transporter Homolog Mch5p Catalyzes Riboflavin (Vitamin B2) Uptake in Saccharomyces cerevisiae

The Monocarboxylate Transporter Homolog Mch5p Catalyzes Riboflavin (Vitamin B2) Uptake in Saccharomyces cerevisiae

The Reacquisition of Biotin Prototrophy in Saccharomyces cerevisiae Involved Horizontal Gene Transfer, Gene Duplication and Gene Clustering

Mechanisms of Biotin Transport

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