Figure 7.—

The PHO pathway might be networked with other cellular signaling pathways that are important for cell survival. Genes required for efficient PHO5 induction under no-phosphate conditions are boxed on the left next to the known PHO pathway, whereas genes required for PHO5 repression under high-phosphate conditions are boxed on the right. Regulation of adenosine nucleotides might have an effect on the PHO pathway by acting upstream of PHO81, while the other processes seem to contribute to PHO5 regulation at levels of transcription and other processes downstream of PHO4.