V-ATPase dysfunction suppresses polyphosphate synthesis in Saccharomyces cerevisiae

Abstract

The yeast Saccharomyces cerevisiae accumulates the high levels of inorganic polyphosphates (polyPs) performing in the cells numerous functions, including phosphate and energy storage. The effects of vacuolar membrane ATPase (V-ATPase) dysfunction were studied on polyP accumulation under short-term cultivation in the Pi-excess media after Pi starvation. The addition of bafilomycin A1, a specific inhibitor of V-ATPase, to the medium with glucose resulted in strong inhibition of the synthesis of long-chain polyP and in substantial suppression of short-chain polyP. The addition of bafilomycin to the medium with ethanol resulted in decreased accumulation of high-molecular polyP, while the accumulation of low-molecular polyP was not affected. The levels of polyP synthesis in the mutant strain with a deletion in the vma2 gene encoding a V-ATPase subunit were significantly lower than in the parent strain in the media with glucose and with ethanol. The synthesis of the longest chain polyP was not observed in the mutant cells. The synthesis of only the low-polymer acid-soluble polyP fraction occurred in the cells of the mutant strain. However, the level of polyP1 was nearly tenfold lower than compared to the cells of the parent strain. Both bafilomycin A1 and the mutation in vacuolar ATPase subunit vma2 lead to a considerable decrease of cellular polyP accumulation. Thus, the defects in ΔμH(+) formation on the vacuolar membrane resulted in the decrease of polyP biosynthesis in S. cerevisiae.

The Reduced Level of Inorganic Polyphosphate Mobilizes Antioxidant and Manganese-Resistance Systems in Saccharomyces cerevisiae

“…The synthesis of the major part of polyP pool is provided by the vacuolar transporter chaperone (VTC) complex of the vacuolar membrane [28,33]. The reduced polyP accumulation was observed in mutants without VTC4 [34] and VTC5 [33], and in knockout strains lacking subunits of vacuolar V-ATPase [35]. All such mutants either lack some components of the VTC complex, being deficient in V-ATPase assembly and stability [36], or lack V-ATPase per se.…”

pH homeostasis in yeast; the phosphate perspective

“…Consistently, the synthesis of long-chain PolyPs is compromised, when the activity of the V-ATPase is pharmacologically inhibited and in cells lacking the V-ATPase subunit Vma2. In addition, the total PolyP content and chain length in wild-type cells not only depend on Pi supply, but also differ significantly depending on the growth phase and availability of either ethanol or glucose as carbon source (Tomaschevsky et al 2010 ; Trilisenko et al 2013 ). Given the compensatory interplay between the V-ATPase and Pma1, it is not surprising that mutations in Pma1 also affect the chain length of PolyPs (Tomashevski and Petrov 2015a , b ).…”

High-Spin Ferric Ions in Saccharomyces cerevisiae Vacuoles Are Reduced to the Ferrous State during Adenine-Precursor Detoxification

“…41 Consistent with this, YAB↑ cells, although grown for 5 days, afforded higher mitochondrial heme levels than equivalent MM cells. Increased vacuolar pH also inhibits synthesis of long-chain polyphosphates, 43 which might be ligands of vacuolar Fe III . 13 Thus, the shift toward nanoparticles at high vacuolar pH may also be related to changes in polyphosphate concentrations.…”