Probable DNA-binding transcriptional activator. Key determinant of the keratinocyte proliferation-differentiation switch involved in appropriate epidermal development. Plays a role in regulating mammary epithelial cell proliferation. May regulate WDR65 transcription. Interacts with SERPINB5. Translocates to nucleus in response to an activating signal. High levels of expression along the medial edge of the fusing palate, tooth buds, hair follicles, genitalia and skin. Phosphorylated. Phosphorylation status depends on the cell cycle and is a signal for ubiquitination and proteasome-mediated degradation. Belongs to the IRF family.