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.

ABCC Subfamily Vacuolar Transporters are Involved in Pb (Lead) Detoxification in Saccharomyces cerevisiae

“…Two parallel pathways for Pb sequestration can occur: one dependent of H + gradient generated by the V-ATPAse as previously described [14] and another mediated by ABCC transporters presented here. For Pb concentrations up to 250 μmol L −1 , the toxic effect was not felt in strains without glutathione transferase (Gtt1p and Gtt2p) or ABCC vacuolar transporters (Figs.…”

“…In a previous work, it was shown the involvement of vacuole and the functional V-ATPase in Pb detoxification [14]. Fig.…”

“…It was described as the sequestration of Co, Cu, Ni and Zn in the vacuole of yeast cells [13]. Recently, it was also shown the involvement of the vacuole in Pb detoxification in yeast cells [14]. In S. cerevisiae, it has been reported that the ATP-binding cassette (ABC) transporter Ycf1p constitutes a major pathway for vacuolar compartmentalization of GSHconjugated xenobiotics and metals, such as Cd and Hg [15][16][17].…”

The FgSsb‐FgZuo‐FgSsz complex regulates multiple stress responses and mycotoxin production via folding the soluble SNARE Vam7 and β2‐tubulin in Fusarium graminearum

“…Functions of the FgSsb-FgZuo-FgSsz complex 5051 of glutathione-conjugated metals in S. cerevisiae (Paumi et al, 2009;Sousa et al, 2014). In this study, we found that lack of the complex FgSsb-FgZuo-FgSsz affected vacuole fusion.…”

“…Vacuolar sequestration of metals is a common detoxification mechanism in eukaryotes (Wysocki and Tam as, 2010). In S. cerevisiae, vacuole has been found to be involved in the sequestration of heavy metals Co, Cu, Ni, Zn and Pb (Macdiarmid et al, 2002;Sousa et al, 2014). The ATP-binding cassette (ABC) transporter Ycf1 constitutes a major pathway for vacuolar compartmentalization Fig.…”