Functional characterization of genes encoding cadmium pumping P1B-type ATPases in Aspergillus fumigatus and Aspergillus nidulans

Ildikó Vig; Zsigmond Benkő; Barnabás Cs Gila; Zoltán Palczert; Ágnes Jakab; Fruzsina Nagy; Márton Miskei; Mi-Kyung Lee; Jae-Hyuk Yu; István Pócsi; Tamás Emri

doi:10.1128/spectrum.00283-23

Functional characterization of genes encoding cadmium pumping P_1B-type ATPases in Aspergillus fumigatus and Aspergillus nidulans

Microbiol Spectr. 2023 Sep 7;11(5):e0028323. doi: 10.1128/spectrum.00283-23. Online ahead of print.

Authors

Ildikó Vig^{1

2}, Zsigmond Benkő¹, Barnabás Cs Gila¹, Zoltán Palczert¹, Ágnes Jakab³, Fruzsina Nagy³, Márton Miskei², Mi-Kyung Lee⁴, Jae-Hyuk Yu⁵, István Pócsi^{1

2}, Tamás Emri^{1

2}

Affiliations

¹ Department of Molecular Biotechnology and Microbiology, Faculty of Sciences and Technology, University of Debrecen , Debrecen, Hungary.
² ELRN-UD Fungal Stress Biology Research Group , Debrecen, Hungary.
³ Department of Medical Microbiology, Faculty of Medicine, University of Debrecen , Debrecen, Hungary.
⁴ Biological Resource Center, Korea Research Institute of Bioscience and Biotechnology , Jeongeup-si, South Korea.
⁵ Department of Bacteriology, University of Wisconsin-Madison , Madison, Wisconsin, USA.

Abstract

Several P_1B-type ATPases are important Cd²⁺/Cu²⁺ pumps in Aspergillus 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_1B-type ATPases, Aspergillus nidulans CrpA Cd²⁺/Cu²⁺ pump (orthologue of the Candida albicans Crp1 Cd²⁺/Cu²⁺ pump) and Aspergillus fumigatus PcaA Cd²⁺ pump (orthologue of the Saccharomyces cerevisiae Pca1 Cd²⁺ pump), we have generated individual mutants and characterized their heavy metal susceptibilities. The deletion of CrpA in A. nidulans has led to the increased sensitivity of the fungus to stresses induced by Zn²⁺, Fe²⁺, or the combination of oxidative-stress-inducing menadione sodium bisulfite and Fe³⁺. Heterologous expression of A. fumigatus PcaA in the S. cerevisiae pca1 deletion mutant has resulted in enhanced tolerance of the yeast to stresses elicited by Cd²⁺or Zn²⁺ but not by Fe²⁺/Fe³⁺ or Cu²⁺. Mammalian host immune defense can attack microbes by secreting Zn²⁺ or Cu²⁺, and the oxidative stress induced by host immune systems can also disturb metal (Cu²⁺, Fe²⁺, and Zn²⁺) homeostasis in microbes. In summary, PcaA and CrpA can protect fungal cells from these complex stresses that contribute to the virulence of the pathogenic Aspergillus species. Moreover, due to their presence on the fungal cell surface, these P_1B-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 Aspergillus fumigatus and Aspergillus nidulans may help to cope with this stress and serve as virulence traits. In our experiments, both A. nidulans Cd2+/Cu2+ pump CrpA and A. fumigatus 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.

Keywords: Aspergillus fumigatus; Aspergillus nidulans; CrpA copper pump; P1B-type ATPase; PcaA cadmium pump; heavy metal homeostasis; virulence; zinc toxicity.