Functional characterization of genes encoding cadmium pumping P-type ATPases in and .

Several P-type ATPases are important Cd/Cu pumps in species, and they are tightly associated with the heavy metal stress tolerance of these ascomycetous fungi. To better understand the roles of the two P-type ATPases, CrpA Cd/Cu pump (orthologue of the Cd/Cu pump) and PcaA Cd pump (orthologue of the Pca1 Cd pump), we have generated individual mutants and characterized their heavy metal susceptibilities. The deletion of CrpA in has led to the increased sensitivity of the fungus to stresses induced by Zn, Fe, or the combination of oxidative-stress-inducing menadione sodium bisulfite and Fe. Heterologous expression of PcaA in the deletion mutant has resulted in enhanced tolerance of the yeast to stresses elicited by Cdor Zn but not by Fe/Fe or Cu. Mammalian host immune defense can attack microbes by secreting Zn or Cu, and the oxidative stress induced by host immune systems can also disturb metal (Cu, Fe, and Zn) homeostasis in microbes. In summary, PcaA and CrpA can protect fungal cells from these complex stresses that contribute to the virulence of the pathogenic species. Moreover, due to their presence on the fungal cell surface, these P-type ATPases may serve as a novel drug target in the future. IMPORTANCE Mammalian host immune defense disrupts heavy metal homeostasis of fungal pathogens. P1B-type ATPase of and may help to cope with this stress and serve as virulence traits. In our experiments, both Cd2+/Cu2+ pump CrpA and Cd2+ pump PcaA protected fungal cells from toxic Zn2+, and CrpA also decreased Fe2+ susceptibility most likely indirectly. In addition, CrpA protected cells against the combined stress induced by the oxidative stressor menadione and Fe3+. Since P1B-type ATPases are present on the fungal cell surface, these proteins may serve as a novel drug target in the future.