Two glutathione peroxidases in the fungal pathogen Cryptococcus neoformans are expressed in the presence of specific substrates

Tricia A. Missall, Jocie F. Cherry-Harris, Jennifer K. Lodge

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Glutathione peroxidases catalyse the reduction of peroxides by reduced glutathione. To determine if these enzymes are important for resistance to oxidative stress and evasion of the innate immune system by the fungal pathogen Cryptococcus neoformans, two glutathione peroxidase homologues, which share 38% identity, were identified and investigated. In this study, these peroxidases, Gpx1 and Gpx2, their localization, their contribution to total glutathione peroxidase activity, and their importance to the oxidative and nitrosative stress resistance of C. neoformans are described. It is shown that the two glutathione peroxidase genes are differentially expressed in response to stress. While both GPX1 and GPX2 are induced during t-butylhydroperoxide or cumene hydroperoxide stress and repressed during nitric oxide stress, only GPX2 is induced in response to hydrogen peroxide stress. Deletion mutants of each and both of the glutathione peroxidases were generated, and it was found that they are sensitive to various peroxide stresses while showing wild-type resistance to other oxidant stresses, such as superoxide and nitric oxide. While the glutathione peroxidase mutants are slightly sensitive to oxidant killing by macrophages, they exhibit wild-type virulence in a mouse model of cryptococcosis.

Original languageEnglish
Pages (from-to)2573-2581
Number of pages9
JournalMicrobiology
Volume151
Issue number8
DOIs
StatePublished - Aug 2005
Externally publishedYes

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