Required for activity of HDA1 histone deacetylase complex. The HDA1 histone deacetylase complex is responsible for the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Heterodimer with HDA3. Component of the HDA1 histone deacetylase complex composed of at least one HDA1 homodimer and one HDA2/HDA3 heterodimer. Interacts with HDA1 and HDA3. Present with 1500 molecules/cell in log phase SD medium. Belongs to the HDA2/3 family. HDA2 subfamily.