title: A collection of yeast mutants selectively resistant to ionophores acting on mitochondrial inner membrane.
abstract: Valinomycin and nigericin are potassium ionophores acting selectively on the mitochondrial inner membrane of Saccharomyces cerevisiae [Kovac, L., Bohmerova, E., Butko, P., 1982a. Ionophores and intact cells. I. Valinomycin and nigericin act preferentially on mitochondria and not on the plasma membrane of Saccharomyces cerevisiae. Biochim. Biophys. Acta 721, 341-348]. However, the molecular mechanism of their action is not understood. Here we show that their selective effect on mitochondrial membranes is not caused by the pleiotropic drug resistance system. To identify the molecular components mediating the action of ionophores we isolated several mutants specifically resistant to valinomycin and/or nigericin. In contrast to the parental strain, these mutants do not form respiratory-deficient cells in the presence of ionophores. Moreover, all mutants harbor extensively fragmented mitochondria and these morphological defects can be alleviated by the ionophores. Interestingly, we observed that these mitochondrial defects may be accompanied by changes in vacuolar dynamics. Our results demonstrate that the classical genetic approach can provide a starting point for the analysis of components involved in the action of ionophores on mitochondria-related processes in eukaryotic cell.
authors.affiliation: Department of Genetics, Comenius University, Faculty of Natural Sciences, Mlynska Dolina, 842 15 Bratislava, Slovak Republic. petrezselyova@fns.uniba.sk <petrezselyova@fns.uniba.sk>
authors.forename: Silvia
authors.initials: S
authors.lastname: Petrezselyova
authors.forename: Jana
authors.initials: J
authors.lastname: Lalakova
authors.forename: Lenka
authors.initials: L
authors.lastname: Abelovska
authors.forename: Vlasta
authors.initials: V
authors.lastname: Klobucnikova
authors.forename: Lubomir
authors.initials: L
authors.lastname: Tomaska
mesh_terms: D025141:Drug Resistance, Fungal / Q000235:genetics*; D007476:Ionophores / Q000494:pharmacology*; D051336:Mitochondrial Membranes / Q000187:drug effects* / Q000648:ultrastructure; D009154:Mutation; D009550:Nigericin / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014634:Valinomycin / Q000494:pharmacology*
chemical_list: D007476:Ionophores; D014634:Valinomycin; D009550:Nigericin