Exogenous oxidative stress induces Ca²⁺ release in the yeast Saccharomyces cerevisiae

Abstract

The Ca2+‐dependent response to oxidative stress caused by H2O2 or tert‐butylhydroperoxide (tBOOH) was investigated in Saccharomyces cerevisiae cells expressing transgenic cytosolic aequorin, a Ca2+‐dependent photoprotein. Both H2O2 and tBOOH induced an immediate and short‐duration cytosolic Ca2+ increase that depended on the concentration of the stressors. Sublethal doses of H2O2 induced Ca2+ entry into the cytosol from both extracellular and vacuolar sources, whereas lethal H2O2 shock mobilized predominantly the vacuolar Ca2+. Sublethal and lethal tBOOH shocks induced mainly the influx of external Ca2+, accompanied by a more modest vacuolar contribution. Ca2+ transport across the plasma membrane did not necessarily involve the activity of the Cch1p/Mid1p channel, whereas the release of vacuolar Ca2+ into the cytosol required the vacuolar channel Yvc1p. In mutants lacking the Ca2+ transporters, H2O2 or tBOOH sensitivity correlated with cytosolic Ca2+ overload. Thus, it appears that under H2O2‐induced or tBOOH‐induced oxidative stress, Ca2+ mediates the cytotoxic effect of the stressors and not the adaptation process.

Molecular Bases of Multimodal Regulation of a Fungal Transient Receptor Potential (TRP) Channel

“…2F) in a concentration-dependent manner, with a similar range between 0.2 and 5.0 mM (Fig. 2G), as reported by Popa et al (59). The level of responses was not saturated within the range of the tested H 2 O 2 concentration.…”

Organellar mechanosensitive channels in fission yeast regulate the hypo-osmotic shock response

“…In fact, an excessive elevation in [Ca 2 + ] i under stress conditions is known to cause apoptosis-like cell death in yeast 32 . Thus, we measured quantitatively the change in [Ca 2 + ] i using aequorin to (Fig.…”

Redox regulation of the yeast voltage-gated Ca2+ channel homolog Cch1p by glutathionylation of specific cysteine residues

“…Previous studies have indicated that both Cch1p and Yvc1p respond to oxidative stress (Popa et al, 2010). To determine whether the responses of Cch1p and Yvc1p to oxidative stress followed similar patterns, we investigated the influx of Ca 2+ into the cytoplasm during activation using individual deletions of these transporters, thereby ensuring that any interference could be eliminated.…”

“…Although Cch1p shows significant sequence and structural homology to VGCCs, Ca 2+ movement through Cch1p is not voltage dependent (Martin et al, 2011). Studies on Cch1p have revealed that it responds to different stimuli that include a sudden increase in pH (Viladevall et al, 2004), exposure to mating pheromones (Iida et al, 1994;Muller et al, 2001), store-operated stress (D'hooge et al, 2015;Locke et al, 2000), endoplasmic reticulum (ER) stress (Hong et al, 2010;Locke et al, 2000) and oxidative stress (Popa et al, 2010).…”

“…In the yeast Saccharomyces cerevisiae, it has recently been shown that the yeast vacuolar Ca 2+ channel Yvc1p, a member of the transient receptor potential (TRP) family of Ca 2+ channels, responds to the redox state in the cell to regulate Ca 2+ levels under conditions of glutathione depletion and extracellular oxidative stress through specific glutathionylation of cysteine residues (Chandel et al, 2016). As the yeast VGCC homolog, Cch1p also appears to respond to oxidative stress (Chandel et al, 2016;Popa et al, 2010), in the present study, we have investigated in detail the redox sensitivity of Cch1p. We show that Cch1p responds to the redox state in the cell and that both the rapid and the slow activation modes of Cch1p activation function in a conserved redox-dependent manner.…”