Global Profiling of 2-hydroxyisobutyrylome in Common Wheat.

As a novel post-translational modification (PTM), lysine 2-hydroxyisobutyrylation (Khib) was considered to regulate gene transcriptional activity in eukaryotic cells and yeast, but the function of Khib proteins in plants remains unknown. Here, we report that Khib is an evolutionarily-conserved PTM in wheat and its donators. Proteomic analysis shows that there are 3348 Khib lysine modification sites from 1074 proteins in common wheat (Triticum aestivum L.) using affinity purification and mass spectroscopy of 2-hydroxyisobutyrylome. Bioinformatic data indicates that Khib proteins participate in a wide variety of biological and metabolic pathways. Immunoprecipitation (IP) confirmed that Khib proteins have an in vivo origin. A comparison of Khib and other major PTMs shows that Khib proteins are simultaneously modified by multiple PTMs. Using mutagenesis experiments and Co-IP, we demonstrate that Khib on K206 is a key regulatory modification of phosphoglycerate kinase (PGK) enzymatic activity, and mutation of the Khib site affects protein interactions of PGK and its substrates. Furthermore, Khib production of low-molecular-weight proteins is a response to the deacetylase inhibitors nicotinamide and trichostatin. This study provides evidence that enhances our current understanding of Khib in wheat plants, including the cooperation between this PTM and its metabolic regulation.