Polycomb group (PcG) protein. Component of the PRC2/EED-EZH2 complex, which methylates 'Lys-9' and 'Lys-27' of histone H3, leading to transcriptional repression of the affected target gene. Also recognizes 'Lys-26' trimethylated histone H1 with the effect of inhibiting PRC2 complex methyltransferase activity on nucleosomal histone H3 'Lys-27', whereas H3 'Lys-27' recognition has the opposite effect, enabling the propagation of this repressive mark (By similarity). The PRC2/EED-EZH2 complex may also serve as a recruiting platform for DNA methyltransferases, thereby linking two epigenetic repression systems (By similarity). Component of the PRC2/EED-EZH2 complex, which includes EED, EZH2, SUZ12, RBBP4 and RBBP7 and possibly AEBP2 (By similarity). The minimum components required for methyltransferase activity of the PRC2/EED-EZH2 complex are EED, EZH2 and SUZ12. Component of the PRC2/EED-EZH1 complex, which includes EED, EZH1, SUZ12, RBBP4 and AEBP2 (By similarity). The PRC2 complex may also interact with DNMT1, DNMT3A, DNMT3B and PHF1 via the EZH2 subunit and with SIRT1 via the SUZ12 subunit (By similarity). Interacts with HDAC, HDAC2, histone H1, KMT2A/MLL1 and YY1 (By similarity). May interact with ITGA4, ITGAE and ITGB7 (By similarity). Interacts with CDYL. Interacts with ARNTL/BMAL1 (By similarity). The WD repeat domain mediates recognition of trimethylated histone peptides at the consensus sequence Ala-Arg-Lys-Ser. This is achieved through an aromatic cage encircling the methyllysine, and involving Phe-97, Tyr-148 and Tyr-365 (By similarity). Methylated. Binding to histone H1 'Lys-26' promotes mono-, di-, and trimethylation of internal lysines (By similarity). Belongs to the WD repeat ESC family.