Global Analysis of Lysine 2-Hydroxyisobutyrylome upon SAHA Treatment and Its Relationship with Acetylation and Crotonylation.

Lysine 2-hydroxyisobutyrylation is a newly discovered protein acylation and was reported to share acyltransferases and deacylases with the widely studied lysine acetylation. The well-known acetyltransferase Tip60 and histone deacetylases HDAC 2 and HDAC 3 were discovered to be "writer" and "eraser" of this new PTM on histones. However, the acyltransferases and deacylases for nonhistone proteins are still unclear. In this work, lysine 2-hydroxyisobutyrylome on both histones and nonhistone proteins upon SAHA treatment were intensively studied and 8765 lysine 2-hydroxyisobutyrylation sites on 2484 proteins were identified in A549 cells. This is the largest data set of lysine 2-hydroxyisobutyrylome in mammalian cells to date. It was found that lysine 2-hydroxyisobutyrylation participates in varieties of biological functions and processes including ribosome, glycolysis/gluconeogenesis, and transcription. More importantly, it was found that most quantified sites on core histones were up-regulated upon SAHA treatment for all 2-hydroxyisobutyrylation, crotonylation, and acetylation and the fold changes upon SAHA of 2-hydroxyisobutyrylation and crotonylation on nonhistone proteins were highly correlated, while their fold changes have little correlations with acetylation on nonhistone proteins.