BCOR and BCORL1 proteins. (A) The BCOR protein is characterized by the BCL6 binding site, the AF9 (MLLT3) binding site, the ANK repeats, and the PUFD binding site capable to dimerize with PCGF1. When the BCOR PUFD domain binds to the RAWUL domain of PCGF1, the complex acquires stability and therefore BCOR is able to interact with the leucine-rich repeat domains of KDM2B. Other components of the multiprotein complex include the catalytic enzyme RING1A/B, RYPB, and SKP1. (B) The BCORL1 protein is characterized by the CtBP1 binding site (CBS), 2 LXXLL (nuclear receptor recruitment motifs), the ANK repeats, and the PUFD binding site.