Site-specific profiling of lysine Itaconylation via a thiol-based probe.

Lysine itaconylation is a novel post-translational modification (PTM) that was recently discovered in macrophage proteomes mediated by the immunoregulatory metabolite, itaconate. However, comprehensive and high-accuracy analytical methods are currently lacking for the global identification of itaconylation sites in proteomes, which limits the study of their biological functions. Here, we developed a thiol-based bioorthogonal probe, BMAyne, to site-specifically profile itaconylation in macrophage proteomes by a chemoproteomic strategy. Notably, 31 endogenous itaconylation sites on 29 proteins were identified in lipopolysaccharide (LPS)-stimulated macrophages using BMAyne probe, which complemented the results obtained previously by the promiscuous antibody enrichment. Our effort provides a unique chemical tool to enrich endogenous lysine itaconylation and establishes a rich database for guiding subsequent functional studies of this unique lysine PTM.