Nutrient sensing and signaling in the yeastSaccharomyces cerevisiae

Abstract

The yeast Saccharomyces cerevisiae has been a favorite organism for pioneering studies on nutrient-sensing and signaling mechanisms. Many specific nutrient responses have been elucidated in great detail. This has led to important new concepts and insight into nutrient-controlled cellular regulation. Major highlights include the central role of the Snf1 protein kinase in the glucose repression pathway, galactose induction, the discovery of a G-protein-coupled receptor system, and role of Ras in glucose-induced cAMP signaling, the role of the protein synthesis initiation machinery in general control of nitrogen metabolism, the cyclin-controlled protein kinase Pho85 in phosphate regulation, nitrogen catabolite repression and the nitrogen-sensing target of rapamycin pathway, and the discovery of transporter-like proteins acting as nutrient sensors. In addition, a number of cellular targets, like carbohydrate stores, stress tolerance, and ribosomal gene expression, are controlled by the presence of multiple nutrients. The protein kinase A signaling pathway plays a major role in this general nutrient response. It has led to the discovery of nutrient transceptors (transporter receptors) as nutrient sensors. Major shortcomings in our knowledge are the relationship between rapid and steady-state nutrient signaling, the role of metabolic intermediates in intracellular nutrient sensing, and the identity of the nutrient sensors controlling cellular growth.

Yeast RNA-Binding Protein Nab3 Regulates Genes Involved in Nitrogen Metabolism

“…2B). Many of the genes that are elevated in response to Nab3 depletion are, like GLT1, regulated by nitrogen catabolite repression (NCR) ( Table 1, genes in boldface) (46,47). This includes genes for a transcription factor that regulates genes involved in nitrogen metabolism (DAL80), an enzyme at the hub of nitrogen metabolism (GLT1), and a number of transporters involved in nitrogen acquisition (GAP1, MEP2, MEP3, and UGA4).…”

Arbuscular Mycorrhizal Symbiosis Requires a Phosphate Transceptor in the Gigaspora margarita Fungal Symbiont

“…These data provided new insights into the transport and signaling functions of the GigmPT transceptor in fungal cells. On the basis of the aforementioned data, we also propose the hypothesis that depletion and repletion of nutrients (P or C) affect a common PKA pathway (Conrad et al, 2014) in response to conditions that promoted AM fungal growth and development. In the first version of the scheme for Pi sensing and signaling networks, it has been proposed that GigmPT protein is predominantly located in ERM, arbuscules, and intraradical hyphae in G. margarita ( Figure 9), and that GigmPT is functional in the PHO pathway in the absence of Pi (Supplemental Figure 20A and 20C) and is inactive under abundant Pi conditions regarding transcription of Pi-repressible genes, while GigmPT is functional in the PKA signaling cascade in the presence of Pi regarding a response in PKA targets (Supplemental Figure 20B and 20D).…”

A large-scale analysis of autophagy-related gene expression identifies new regulators of autophagy

“…Gln3 and Gat1 are both part of the GATA family of transcription factors and bind to similar DNA motifs. [27][28][29][30] The double deletion gat1D gln3D did not have an additive effect on ATG expression after nitrogen starvation compared to the single gln3D or gat1D strain (Fig. 2C) suggesting that the 2 proteins may recognize the same consensus sites on ATG promoters and work together to induce their transcription.…”