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Functional characterization of the ferroxidase, permease high‐affinity iron transport complex from Candida albicans
Author(s) -
Ziegler Lynn,
Terzulli Alaina,
Gaur Ruchi,
McCarthy Ryan,
Kosman Daniel J.
Publication year - 2011
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2011.07704.x
Subject(s) - candida albicans , biology , permease , corpus albicans , saccharomyces cerevisiae , cryptococcus neoformans , fungal protein , yeast , biochemistry , virulence , multicopper oxidase , transport protein , gene , microbiology and biotechnology , transporter , enzyme , laccase
Summary Saccharomyces cerevisiae expresses two proteins that together support high‐affinity Fe‐uptake. These are a multicopper oxidase, Fet3p, with specificity towards Fe 2+ and a ferric iron permease, Ftr1p, which supports Fe‐accumulation. Homologues of the genes encoding these two proteins are found in all fungal genomes including those for the pathogens, Candida albicans and Cryptococcus neoformans . At least one of these loci represents a virulence factor for each pathogen suggesting that this complex would be an appropriate pharmacologic target. However, the mechanism by which this protein pair supports Fe‐uptake in any fungal pathogen has not been elucidated. Taking advantage of the robust molecular genetics available in S. cerevisiae , we identify the two of five candidate ferroxidases likely involved in high‐affinity Fe‐uptake in C. albicans , Fet31 and Fet34. Both localize to the yeast plasma membrane and both support Fe‐uptake along with an Ftr1 protein, either from C. albicans or from S. cerevisiae . We express and characterize Fet34, demonstrating that it is functionally homologous to Sc Fet3p. Using S. cerevisiae as host for the functional expression of the C. albicans Fe‐uptake proteins, we demonstrate that they support a mechanism of Fe‐trafficking that involves channelling of the Ca Fet34‐generated Fe 3+ directly to Ca Ftr1 for transport into the cytoplasm.