title: The dual mechanism of the antifungal effect of new lysosomotropic agents on the Saccharomyces cerevisiae RXII strain.
abstract: Quinacrine was used to visualize the intracellular pH changes in the yeast strain Saccharomyces cerevisiae RXII occurring after exposure to four recently-synthesized lysosomotropic drugs: DM-11, PY-11, PYG-12s and DMAL-12s. The cells took up quinacrine, mostly accumulating it in their vacuoles. DM-11 and PY-11 gave rise to diffuse quinacrine fluorescence throughout the cells, with the vacuoles staining to a somewhat greater extent than the cytosol. This quinacrine-detected overall acidification of the cell interior is very probably caused by blocking of plasma membrane H(+)-ATPase. PYG-12s gave rise to a strong vacuolar accumulation of the dye. Like the vacuolar ATPase inhibitor bafilomycin A(1), DMAL-12s strongly lowered the intensity of quinacrine fluorescence. Owing to its low pK(a), it can penetrate rapidly into the cells and may inhibit vacuolar H(+)-ATPase and prevent quinacrine-detectable vacuolar acidification without causing strong cell acidification. Since these drugs were found to penetrate into the cells, their lack of effect may reflect a higher resistance of both plasma membrane H(+)-ATPase and vacuolar ATPase to the drugs. Our data indicate that the lysosomotropic drugs under study have a dual action. On entering the cell, they cause intracellular acidification, very probably by inhibiting plasma membrane H(+)-ATPase and curtailing active proton pumping from the cells. Furthermore, they interfere with the function of V-type ATPase, causing vacuolar alkalinization and eventually cell death.
authors.affiliation: Institute of Microbiology, Wrocław University, Przybyszewskiego 63-77, Poland. aniak@microb.uni.wroc.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Krasowska
authors.forename: Lucyna
authors.initials: L
authors.lastname: Chmielewska
authors.forename: Jacek
authors.initials: J
authors.lastname: Łuczyński
authors.forename: Stanisław
authors.initials: S
authors.lastname: Witek
authors.forename: Karel
authors.initials: K
authors.lastname: Sigler
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D006863:Hydrogen-Ion Concentration; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008247:Lysosomes / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D006180:Proton-Translocating ATPases / Q000378:metabolism; D011796:Quinacrine / Q000493:pharmacokinetics; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D005456:Fluorescent Dyes; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases; D011796:Quinacrine