Transcriptional activator that binds to the regulatory region of MMP3 and thereby controls stromelysin expression. It stimulates the activity of various transcriptional activators such as JUN, SP1, PAX6 and ETS1, suggesting a function as a coactivator. Homodimer (Probable). Interacts with RNF4 and JUN. Binds to the regulatory region of MMP3. Expressed in brain, lung, liver, kidney and testes. Isoform 2 is exclusively expressed at 7-11 days of development. Isoform 1 is found only at low levels in 15-17 days embryos. The atypical PHD domain functions as a negative modulator of cofactor binding.