New aspects on phosphate sensing and signalling in Saccharomyces cerevisiae

Abstract

The mechanism involved in the cellular phosphate response of Saccharomyces cerevisiae forms part of the PHO pathway, which upon expression allows a co-ordinated cellular response and adaptation to changes in availability of external phosphate. Although genetic studies and analyses of the S. cerevisiae genome have produced much information on the components of the PHO pathway, little is known about how cells sense the environmental phosphate level and the mechanistic regulation of phosphate acquisition. Recent studies emphasize different levels in phosphate sensing and signalling in response to external phosphate fluctuations. This review integrates all these findings into a model involving rapid and long-term effects of phosphate sensing and signalling in S. cerevisiae. The model describes in particular how yeast cells are able to adjust phosphate acquisition by integrating the status of the intracellular phosphate pools together with the extracellular phosphate concentration.

Pho85p-Pho80p Phosphorylation of Yeast Pah1p Phosphatidate Phosphatase Regulates Its Activity, Location, Abundance, and Function in Lipid Metabolism

“…In brief, low phosphate leads to the Pho81p-mediated inhibition of Pho85p-Pho80p activity and the induction of PHO genes and their products for foraging phosphate from the environment (60). When phosphate levels are replete, Pho85p-Pho80p is active to inhibit expression of PHO genes (28,60).…”

“…Pho85p-Pho80p phosphorylation is known for its involvement in the regulation of phosphate metabolism (28,60). In brief, low phosphate leads to the Pho81p-mediated inhibition of Pho85p-Pho80p activity and the induction of PHO genes and their products for foraging phosphate from the environment (60).…”

Phosphate homeostasis in the yeast Saccharomyces cerevisiae, the key role of the SPX domain‐containing proteins

“…However, the activation of the PKA signaling pathway by glycerol-3-phosphate only requires Pho84 [43]. Thus, Pho84 is considered as a transceptor, having both nutrient transport and signaling functions, while the transceptor capacity of Pho87 still remains to be confirmed [3,4,43].…”

“…For most organisms the availability of Pi in the environment is a growth limiting factor. In the budding yeast Saccharomyces cerevisiae, Pi sensing, acquisition, and storage are mainly mediated by the phosphate-responsive signaling pathway, referred to as the PHO pathway [1][2][3][4]. Under Pi deficiency, the PHO operon, which controls a set of genes aimed at increasing Pi uptake and Pi use efficiency, is triggered.…”

Phosphate (Pi)-regulated heterodimerization of the high-affinity sodium-dependent Pi transporters PiT1/Slc20a1 and PiT2/Slc20a2 underlies extracellular Pi sensing independently of Pi uptake

“…In case of a low extracellular Pi level, this system increases the efficiency of Pi retention in the bacteria (38). In Saccharomyces cerevisiae, a low extracellular Pi level resulted in induction of the Pi transporter Pho84, now identified as the essential component of the Pi-sensing system (38,39). Interestingly, following Pi restriction it was demonstrated that Pho84 could trigger the rapid activation of protein kinase A without transporting Pi (40).…”