Function
Cyclin partner of the cyclin-dependent kinase (CDK) PHO85. Negatively regulates the expression of phosphate-starvation-responsive genes under phosphate-rich conditions. The PHO80-PHO85 cyclin-CDK holoenzyme phosphorylates and inactivates the transcription factor PHO4, by preventing its association with the transcription factor PHO2 and the nuclear import receptor PSE1, and by promoting association with the nuclear export receptor MSN5, excluding PHO4 from the nucleus. PHO80-PHO85 phosphorylates and inactivates protein kinase RIM15 by retaining it in the cytoplasm, antagonizing RIM15-induced entry into stationary phase. PHO80-PHO85 also phosphorylates and inactivates the calcineurin-responsive transcription factor CRZ1, linking PHO85 to calcium signaling.