Component of the RPD3C(L) histone deacetylase complex (HDAC) 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. Component of the RPD3C(L) complex composed of at least ASH1, CTI6, DEP1, PHO23, RPD3, RXT2, RXT3, SAP30, SDS3, SIN3, UME1 and UME6.