New types of modifications of histones keep emerging. Recently, histone H4K8 2-hydroxyisobutyrylation (H4K8hib) was identified as an evolutionarily conserved modification. However, how this modification is regulated within a cell is still elusive, and the enzymes adding and removing 2-hydroxyisobutyrylation have not been found. Here, we report that the amount of H4K8hib fluctuates in response to the availability of carbon source in Saccharomyces cerevisiae and that low-glucose conditions lead to diminished modification. The removal of the 2-hydroxyisobutyryl group from H4K8 is mediated by the histone lysine deacetylase Rpd3p and Hos3p in vivo. In addition, eliminating modifications at this site by alanine substitution alters transcription in carbon transport/metabolism genes and results in a reduced chronological life span (CLS). Furthermore, consistent with the glucose-responsive H4K8hib regulation, proteomic analysis revealed that a large set of proteins involved in glycolysis/gluconeogenesis are modified by lysine 2-hydroxyisobutyrylation. Cumulatively, these results established a functional and regulatory network among Khib, glucose metabolism, and CLS.
Keywords: chronological life span; histone deacetylase; lysine 2-hydroxyisobutyrylation; lysine acetylation; protein posttranslational modifications.