Transcription factor. Inhibits cell proliferation by activating either CDKN1A/p21 transcription or RB1 transcription. Interacts with EP300, KAT5/Tip60 and ZBTB17. The interaction with EP300 is direct and leads to synergistic induction of CDKN1A. On the CDKN1A promoter, forms a complex with ZBTB17; this interaction leads to additive CDKN1A transactivation. The interaction with ZBTB17 may block ZBTB17 repressor activity. Widely expressed, with highest levels in white adipose tissue and kidney, intermediate levels in brain, liver and heart, and lowest levels in spleen, brown adipose tissue and muscle. Belongs to the krueppel C2H2-type zinc-finger protein family.