Untitled

Abstract

Background: Nutrient minerals are essential yet potentially toxic, and homeostatic mechanisms are required to regulate their intracellular levels. We describe here a genome-wide screen for genes involved in the homeostasis of minerals in Saccharomyces cerevisiae. Using inductively coupled plasma-atomic emission spectroscopy (ICP-AES), we assayed 4,385 mutant strains for the accumulation of 13 elements (calcium, cobalt, copper, iron, potassium, magnesium, manganese, nickel, phosphorus, selenium, sodium, sulfur, and zinc). We refer to the resulting accumulation profile as the yeast 'ionome'.

Identification and Characterization of Vnx1p, a Novel Type of Vacuolar Monovalent Cation/H+ Antiporter of Saccharomyces cerevisiae

“…On the other hand, the growth of the ena1-ena4⌬ vnx1⌬ cells was affected in the presence of either NaCl or LiC, thus indicating the predominant role of Ena1-Ena4 in Na ϩ extrusion. S. cerevisiae is able to accumulate different ions in the cell to up to 3-30 times the external concentration, but Na ϩ are largely excluded, with cells showing only 30% of the Na ϩ concentration of the growth medium (43). Moreover, ionomic analysis of nhx1⌬ and nha1⌬ cells failed to show any significant differences in ion content relative to wild type, reinforcing the notion that Na ϩ -ATPases are predominant in S. cerevisiae Na ϩ homeostasis.…”

Vacuolar H+-ATPase Protects Saccharomyces cerevisiae Cells against Ethanol-Induced Oxidative and Cell Wall Stresses

“…These phenotypes of the vma mutants suggest that the V-ATPase and the plasma membrane H ϩ -ATPases together play an interdependent role in the regulation of intracellular pH homeostasis. In addition to the expected phenotypes of the vma mutants, which are a direct consequence of impaired intracellular pH regulation, these mutants also exhibited other pleiotropic phenotypes, including sensitivity to a variety of oxidants, such as H 2 O 2 (20), sensitivity to transition metals, such as copper and zinc (21,22), poor growth under conditions of both high and low concentrations of calcium and iron (18,23,24), poor growth on nonfermentable carbon sources (25), and defective vacuolar morphology and vacuolar protein sorting (26,27). Some of these phenotypes can be easily explained by an increased accumulation of reactive oxygen species (ROS) or defective vacuolar function, important for storage and sequestration of several metabolites and toxins in these mutants (20,25).…”

Development of Efficient Xylose Fermentation in Saccharomyces cerevisiae: Xylose Isomerase as a Key Component

“…Although S. cerevisiae has been demonstrated to accumulate cobalt intracellularly [18], it is not clear whether this metal is available in the cytosol or sequestered in, for example, the vacuole. Other aspects with potential relevance for yeast metabolic engineering include the high temperature optimum (60-80 • C) and the relatively high pH optimum (7.0-9.0) of many of the XIs that have been characterised [11].…”