Discovery of Itaconate-Mediated Lysine Acylation

Itaconate is an important antimicrobial and immunoregulatory
metabolite
involved in host–pathogen interactions. A key mechanistic action
of itaconate is through the covalent modification of cysteine residues
via Michael addition, resulting in “itaconation”. However,
it is unclear whether itaconate has other regulatory mechanisms. In
this work, we discovered a novel type of post-translational modification
by promiscuous antibody enrichment and data analysis with the open-search
strategy and further confirmed it as the lysine “itaconylation”.
We showed that itaconylation and its precursor metabolite itaconyl-CoA
undergo significant upregulation upon lipopolysaccharides (LPS) stimulation
in RAW264.7 macrophages. Quantitative proteomics identified itaconylation
sites in multiple functional proteins, including glycolytic enzymes
and histones, some of which were confirmed by synthetic peptide standards.
The discovery of lysine itaconylation opens up new areas for studying
how itaconate participates in immunoregulation via protein post-translational
modification.