The nutrient stress response in yeast

Nutrients such as glucose and glutamine provide yeast not only with substrates for energy production and mass accumulation but also with signals specifying the metabolic and transcriptional program appropriate for the condition in which the yeast cells find themselves. In nutrient replete conditions, nutrient signaling pathways activate growth programs promoting both continuous mass accumulation and the discontinuous process of the cell cycle. Under nutrient limiting conditions, these pathways activate a canonical stress response program and attenuate cell growth in proportion to the extent of nutrient limitation. In this review, we describe recent results elaborating the nature of these nutrient signaling pathways. In addition, we describe the short-term and long-term consequences of nutrient limitation on both the canonical stress response and the regulation of cell growth. We highlight the stochastic nature of the stress response, which permits genetically identical cells in a common environment to pursue distinct survival strategies, maximizing the potential for overall persistence of the clonal population regardless of subsequent environmental conditions. Finally, we examine the mechanistic connection between activation of the stress response and attenuation of cell growth. These recent results provide insight not only into the biology of yeast but also on homologous signaling pathways and stress responses of larger eukaryotes.