title: γ-Glutamyl transpeptidase (GgtA) of Aspergillus nidulans is not necessary for bulk degradation of glutathione.
abstract: Aspergillus nidulans exhibited high γ-glutamyl transpeptidase (γGT) activity in both carbon-starved and carbon-limited cultures. Glucose repressed, but casein peptone increased γGT production. Null mutation of creA did not influence γGT formation, but the functional meaB was necessary for the γGT induction. Deletion of the AN10444 gene (ggtA) completely eliminated the γGT activity, and the mRNA levels of ggtA showed strong correlation with the observed γGT activities. While ggtA does not contain a canonical signal sequence, the γGT activity was detectable both in the fermentation broth and in the hyphae. Deletion of the ggtA gene did not prevent the depletion of glutathione observed in carbon-starved and carbon-limited cultures. Addition of casein peptone to carbon-starved cultures lowered the formation of reactive species (RS). Deletion of ggtA could hinder this decrease and resulted in elevated RS formation. This effect of γGT on redox homeostasis may explain the reduced cleistothecia formation of ΔggtA strains in surface cultures.
authors.affiliation: Department of Biotechnology and Microbiology, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H4032, Hungary.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Spitzmüller
authors.forename: Nak-Jung
authors.initials: NJ
authors.lastname: Kwon
authors.forename: Melinda
authors.initials: M
authors.lastname: Szilágyi
authors.forename: Judit
authors.initials: J
authors.lastname: Keserű
authors.forename: Viktória
authors.initials: V
authors.lastname: Tóth
authors.forename: Jae-Hyuk
authors.initials: JH
authors.lastname: Yu
authors.forename: István
authors.initials: I
authors.lastname: Pócsi
authors.forename: Tamás
authors.initials: T
authors.lastname: Emri
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics; D002244:Carbon / Q000378:metabolism; D004789:Enzyme Activation / Q000235:genetics; D017353:Gene Deletion; D005800:Genes, Fungal / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006706:Homeostasis; D025301:Hyphae / Q000201:enzymology; D010084:Oxidation-Reduction; D005723:gamma-Glutamyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D002244:Carbon; D005723:gamma-Glutamyltransferase; D005978:Glutathione; D005947:Glucose