Coordinate responses to alkaline pH stress in budding yeast

Abstract

Alkalinization of the medium represents a stress condition for the budding yeast Saccharomyces cerevisiae to which this organism responds with profound remodeling of gene expression. This is the result of the modulation of a substantial number of signaling pathways whose participation in the alkaline response has been elucidated within the last ten years. These regulatory inputs involve not only the conserved Rim101/PacC pathway, but also the calcium-activated phosphatase calcineurin, the Wsc1-Pkc1-Slt2 MAP kinase, the Snf1 and PKA kinases and oxidative stress-response pathways. The uptake of many nutrients is perturbed by alkalinization of the environment and, consequently, an impact on phosphate, iron/copper and glucose homeostatic mechanisms can also be observed. The analysis of available data highlights cases in which diverse signaling pathways are integrated in the gene promoter to shape the appropriate response pattern. Thus, the expression of different genes sharing the same signaling network can be coordinated, allowing functional coupling of their gene products.

Effects of pH on antioxidant and prooxidant properties of common medicinal herbs

“…Therefore, we supposed that the combined action of two stressors, alkaline pH and hydrogen peroxide, could sensitize yeast cells to H 2 O 2 leading to rapid cell death. It is consistent with previous data that S. ceresiviae cell differentiation programs and proliferation are under tight control of alkalinization of the medium [43]. Our results suggest that certain phytochemicals present in plant extracts are able to stimulate yeast reproduction at acidic pH.…”

“…Yeast S. cerevisiae belongs to acidophilic organisms which grow better at acidic than at neutral or alkaline pHs [42]. Moreover, alkalinization of the medium represents a stress condition for the budding yeast [42,43]. Therefore, we supposed that the combined action of two stressors, alkaline pH and hydrogen peroxide, could sensitize yeast cells to H 2 O 2 leading to rapid cell death.…”

RNA sequencing reveals an additional Crz1-binding motif in promoters of its target genes in the human fungal pathogen Candida albicans

“…Regulation of calcium homeostasis is highly conserved in eukaryotic cells. Gene expression in response to calcium stress is controlled by the calcium/ calcineurin signalling through the transcription factor Crz1 in fungi or the nuclear factor of activated T cells (NFAT) in mammals [6,7]. In Saccharomyces cerevisiae, an increase in cytosolic calcium triggers the calmodulin/Ca 2+ binding and activation of the protein phosphatase, calcineurin.…”

Metabolic constraints and quantitative design principles in gene expression during adaption of yeast to heat shock

“…Four independent experiments were carried out, and for each experiment two samples were processed for each time point (eight replicates per time point). Total RNA isolation and labelling, and determination of mRNA levels were done as described in [23] at 0, 3,6,9,12,15,18,21,25,30,45, and 60 min after heat shock. Values at each time point after the beginning of the experiment were normalized by those at time 0.…”

“…It is firmly established that the sets of yeast genes whose expression is modulated during adaptive responses to different types of stress only partially overlap [24], [25]. For example, TPS1 and TPS2 code for proteins involved in the synthesis of trehalose and change their expression in response to various types of stress [26]- [28], while MEC1 only changes its expression in response to DNA damage, but not to heat shock [27], [29].…”