InterPro domain: IPR004923

Fungi uptake extracellular ferrous iron (Fe2+) using a bipartite high-affinity transporter consisting of a multicopper ferroxidase associated with a membrane permease which translocates generated ferric iron (Fe3+) into the cytosol. The Saccharomyces cerevisiae (Baker's yeast) iron permease FTR1 is a plasma membrane permease for high-affinity iron uptake [ 1 ]. FTR1, together with multicopper oxidase FET3, mediate high-affinity iron uptake. Schizosaccharomyces pombe Fio1 (ferrous iron oxidase) and Fip1 (ferriferous permease), share significant similarity to FET3 and FTR1 from S. cerevisiae [ 2 ]. In Neosartorya fumigata, the high affinity iron permease is known as FtrA [ 3 ].

Many bacteria possess Fe2+ transporters with functional similaritiesto the FET3-FTR1 system. Escherichia coli encodes an EfeUOB transporter where EfeU is homologous to the high-affinity iron permease FTR1 of Saccharomyces cerevisiae [ 4 , 5 ]. Bacillus subtilis encodes similar proteins, but not identical to the E. coli EfeUOB transporter components. B. subtilis EfeUOB uses a transport system that permits the high-affinity acquisition of both Fe2+ and Fe3+ [ 6 ].

This entry also includes the vacuolar iron transporter FTH1 [ 7 ].

1. A permease-oxidase complex involved in high-affinity iron uptake in yeast. Science 271, 1552-7
2. An oxidase-permease-based iron transport system in Schizosaccharomyces pombe and its expression in Saccharomyces cerevisiae. J. Biol. Chem. 272, 401-5
3. Siderophore biosynthesis but not reductive iron assimilation is essential for Aspergillus fumigatus virulence. J. Exp. Med. 200, 1213-9
4. A new ferrous iron-uptake transporter, EfeU (YcdN), from Escherichia coli. Mol. Microbiol. 62, 120-31
5. EfeUOB (YcdNOB) is a tripartite, acid-induced and CpxAR-regulated, low-pH Fe2+ transporter that is cryptic in Escherichia coli K-12 but functional in E. coli O157:H7. Mol. Microbiol. 65, 857-75
6. The Bacillus subtilis EfeUOB transporter is essential for high-affinity acquisition of ferrous and ferric iron. Biochim. Biophys. Acta 1833, 2267-78
7. The iron transporter Fth1p forms a complex with the Fet5 iron oxidase and resides on the vacuolar membrane. J. Biol. Chem. 274, 38061-70