High impact information on FUI1

• The uptake of Urd into the yeast Saccharomyces cerevisiae is mediated by Fui1p, a Urd-specific nucleoside transporter encoded by the FUI1 gene and a member of the yeast Fur permease family, which also includes the uracil, allantoin, and thiamine permeases [1].
• Electrophysiological analysis of recombinant Fui1p produced in Xenopus oocytes demonstrated that Fui1p-mediated Urd uptake was dependent on proton cotransport with a 1:1 stoichiometry [1].
• When Fui1p was produced in a double-permease knock-out strain (fur4Deltafui1Delta) of yeast, Urd uptake was stimulated at acidic pH and sensitive to the protonophore carbonyl cyanide m-chlorophenylhydrazone [1].
• The FUI1-encoded uridine permease is similarly sorted for early vacuolar degradation in cells exposed to a toxic level of uridine uptake [2].
• Nucleoside transporter proteins of Saccharomyces cerevisiae. Demonstration of a transporter (FUI1) with high uridine selectivity in plasma membranes and a transporter (FUN26) with broad nucleoside selectivity in intracellular membranes [3].

Biological context of FUI1

• A strain carrying the disrupted allele and a fui1 mutant exhibit the same phenotype as they do not grow on a medium containing uridine as the sole source of pyrimidines and as they are resistant to 10(-3) M 5-fluorouridine (5FUI), a toxic analog of uridine [4].

Anatomical context of FUI1

• These results indicated that FUI1 has high selectivity for uracil-containing ribonucleosides and imports uridine across cell-surface membranes, whereas FUN26 has broad nucleoside selectivity and most likely functions to transport nucleosides across intracellular membranes [3].

Associations of FUI1 with chemical compounds

• Even though the FUI1 gene has a multicopy suppressor effect on uracil transport, its product does not seem to be involved in this transport, in contrast to the FUR4 gene product which is involved in uridine transport [4].
• The inability to transport uridine indicated that the NUP gene product was different from the Candida uridine permease, which also transported cytosine and adenosine [5].
• In the case of cytosine and uridine permease, a membrane ATPase is possibly involved in the process of energetic coupling whereas this does not seem to be so for uracil [6].

Other interactions of FUI1

• Moreover, the FUI1 gene product does not play any role in allantoin transport [4].

References