MCFOs expression was regulated by iron levels. (A) SDS-PAGE analysis of proteins extracted by heating whole yeast cells of C. albicans SC5314. Cells were cultivated in sufficient iron (YPD) or restricted iron (RIM) medium at 30°C for 5 h, and proteins were extracted as described in the experimental part. (B) Multiple sequence alignment (MSA) of the first 15 amino acids (aa) (given in the single letter code) after excision of a predicted 20 aa signaling peptide of MCFOs. The alignment was performed using CLUSTALW2 and displayed with the Jalview editor (http://www.ebi.ac.uk/Tools/msa/clustalw2/). The selected proteins are: Fet3p [UniProtKB: Q59NF9], Fet31p [UniProtKB: Q59NF7], Fet33 [UniProtKB: Q5A503], Fet34p [UniProtKB: Q59NF5] and Fet99p [UniProtKB: Q59NF8]. (C) SDS-PAGE analysis of MCFOs, which were extracted from cells grown in RPMI supplemented with different iron concentrations at 30°C for 3 h.