Fig 1. UrhB and UrkA mediate the hydrolysis and phosphorylation of 5FUR/uridine.

(A) Scheme illustrating proteins involved in 5FC uptake and pyrimidine salvage pathway based metabolization of fluoropyrimidines in yeast (black) and A. fumigatus (magenta). (B) The role of uridine nucleosidase and uridine kinase encoding genes was determined by susceptibility testing. (C) Resistance analysis was complemented with a reversal assay studying the contribution of enzymes in the metabolization of nucleobases cytosine (Cyt) and uracil (Ura) as well as the nucleoside uridine (Urd) during de novo pyrimidine biosynthesis inhibition.