Transcriptional corepressor. May specifically inhibit gene expression when recruited to promoter regions by sequence-specific DNA- binding proteins such as BCL6. This repression may be mediated at least in part by histone deacetylase activities which can associate with this corepressor. . This is the function of BCORL1 (BCL6 corepressor like 1, Ensembl gene identifier ENSG00000085185).