PUFD is the minimal domain at the C-terminus of BCORL (BCL6 corepressor) that is needed for binding and giving specificity to some of the PCGF proteins, polycomb-group RING finger homologues. PUFD binds to the RAWUL (RING finger- and WD40-associated ubiquitin-like) domain of the particular PCGF PCGF1, Pfam:PF16207. Polycomb group proteins form repressive complexes (PRC) that mediate epigenetic modifications of histones. In humans there are many different PCGF homologues whose functions all vary, but the direct binding partner of PCGF1 is BCOR. BCOR has emerged as an important player in development and health [1].

1: Structure of the polycomb group protein PCGF1 in complex with BCOR reveals basis for binding selectivity of PCGF homologs. Junco SE, Wang R, Gaipa JC, Taylor AB, Schirf V, Gearhart MD, Bardwell VJ, Demeler B, Hart PJ, Kim CA; Structure. 2013;21:665-671. PMID:23523425