Lysine 2-hydroxyisobutyrylatome profiling reveals extensive lysine 2-hydroxyisobutyrylation in common wheat

In this work, we first analyzed wheat (Triticum aestivum L.) lysine Khib sites by mass spectrometry. A total of 3,348 lysine modification sites from 1,047 proteins were identified in wheat seedlings. The identified Kcr proteins were discovered to be widespread. Bioinformatic data indicated these Kcr proteins involved in diverse biology and metabolic processes. Our data indicated that Khib is as dynamic as Kac and Khib changes in response to the deacetylase inhibitors Trichostatin A (TSA) and nicotinamide (NAM). We tested histone Khib and deacylation activities of several wheat HATs and HDACs using wheat Krnose EMS mutants. Finally, we confirmed lysine Khib on K206 of PGK was a regulatory modification using mustagenesis experiments and found that de-Khib impaired protein interactions of PGK. Our data demonstrate that the regulatory scope of lysine Khib is broad and comparable with that of other major PTMs. Wheat histone Khib are dynamically regulated by environmental cues and are likely to be removed by different mechanisms.