Acts as component of the ssn6-tup corepressor complexes, which are involved in the repression of many genes in a wide variety of physiological processes. May also be involved in the derepression of at least some target genes. The complex is recruited to target genes by interaction with DNA-bound transcriptional repressors. The complex recruits histone deacetylases to produce a repressive chromatin structure, interacts with hypoacetylated N-terminal tails of histones H3 and H4 that have been programmed for repression by the action of histone deacetylases and interferes directly with the transcriptional machinery by associating with the RNA polymerase II mediator complex (By similarity). Associates independently with tup11 and tup12 to form ssn6-tup corepressor complexes. Nuclear dots. Belongs to the CYC8/SSN6 family.