Yeast cells modulate their protein synthesis capacity in response to
physiological needs through the transcriptional control of ribosomal protein
(RP) genes. Here we demonstrate that the transcription factor Sfp1,
previously shown to play a role in the control of cell size, regulates RP
gene expression in response to nutrients and stress. Under optimal growth
conditions, Sfp1 is localized to the nucleus, bound to the promoters of RP
genes, and helps promote RP gene expression. In response to inhibition of
target of rapamycin (TOR) signaling, stress, or changes in nutrient
availability, Sfp1 is released from RP gene promoters and leaves the
nucleus, and RP gene transcription is down-regulated. Additionally, cells
lacking Sfp1 fail to appropriately modulate RP gene expression in response
to environmental cues. We conclude that Sfp1 integrates information from
nutrient- and stress-responsive signaling pathways to help control RP gene
expression.