PIF4 plays a central role in integrating light and high temperature signaling to promote growth.
High ambient temperature induces PIF4 expression and also stabilizes PIF4 protein. Multiple regulators have been shown to directly interact with PIF4 and regulate its function by inhibiting DNA binding, transcription activity and protein stability. While two photoreceptors, phyB and Cry1 function to inhibit PIF4 activity in response to red and blue light signals, respectively, only phyB has been shown to act as a thermosensor in Arabidopsis. PIF4 directly activates the expression of YUC/TAA1/CYP79B2 genes to promote growth.