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. Binds to the URS1 site (5'-AGCCGCCGA-3') and recruits the RPD3 histone deacetylase complex to the promoters to negatively regulate the expression of many genes including CAR1 (arginase), several required for sporulation, mating type switching, inositol metabolism, and oxidative carbon metabolism. Recruits also the ISW2 chromatin remodeling complex to promoters in a second gene repression pathway. Associates with the master regulator of meiosis IME1 in order to activate the expression of meiosis genes. Has both a positive and negative role in regulating phospholipid biosynthesis. Component of the RPD3C(L) complex composed of at least ASH1, CTI6, DEP1, PHO23, RPD3, RXT2, RXT3, SAP30, SDS3, SIN3, UME1 and UME6. Interacts with RIM11, MCK1 and IME1. Phosphorylated by RIM11 and MCK1. Present with 217 molecules/cell in log phase SD medium.