Transcriptional regulator that, together with ECM5, recruits histone deacetylase RPD3 to a small number of promoters of stress-response genes in response to oxidative stress (PubMed:23878396). Probable ubiquitin-protein ligase involved in the degradation-related ubiquitination of histones. Contributes to the post-translational regulation of histone protein levels by polyubiquitination of excess histones for subsequent degradation (PubMed:22570702). S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Component of the Snt2C complex composed of SNT2, ECM5 and RPD3. Interacts with the E2 ubiquitin-conjugating enzyme UBC4 and histones H3 and H4. Binding is enhanced to methylated histone H3K36me3. Localizes to promoters of stress-response genes in response to oxidative stress.