title: Saccharomyces cerevisiae mutants affected in vacuole assembly or vacuolar H+-ATPase are hypersensitive to lead (Pb) toxicity.
abstract: Lead is an important environmental pollutant. The role of vacuole, in Pb detoxification, was studied using a vacuolar protein sorting mutant strain (vps16Δ), belonging to class C mutants. Cells disrupted in VPS16 gene, did not display a detectable vacuolar-like structure. Based on the loss of cell proliferation capacity, it was found that cells from vps16Δ mutant exhibited a hypersensitivity to Pb-induced toxicity, compared to wild type (WT) strain. The function of vacuolar H(+)-ATPase (V-ATPase), in Pb detoxification, was evaluated using mutants with structurally normal vacuoles but defective in subunits of catalytic (vma1Δ or vma2Δ) or membrane domain (vph1Δ or vma3Δ) of V-ATPase. All mutants tested, lacking a functional V-ATPase, displayed an increased susceptibility to Pb, comparatively to cells from WT strain. Modification of vacuolar morphology, in Pb-exposed cells, was visualized using a Vma2p-GFP strain. The treatment of yeast cells with Pb originated the fusion of the medium size vacuolar lobes into one enlarged vacuole. In conclusion, it was found that vacuole plays an important role in the detoxification of Pb in Saccharomyces cerevisiae; in addition, a functional V-ATPase was required for Pb compartmentalization.
authors.affiliation: Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072, Porto, Portugal.
authors.forename: Cátia A
authors.initials: CA
authors.lastname: Sousa
authors.forename: Rita R
authors.initials: RR
authors.lastname: Perez
authors.forename: Eduardo V
authors.initials: EV
authors.lastname: Soares
mesh_terms: D007854:Lead / Q000494:pharmacology* / Q000633:toxicity; D050296:Microbial Viability / Q000187:drug effects; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics*; D014617:Vacuoles / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics
chemical_list: D029701:Saccharomyces cerevisiae Proteins; C080045:VPS16 protein, S cerevisiae; D033921:Vesicular Transport Proteins; D007854:Lead; D025262:Vacuolar Proton-Translocating ATPases