Lysine-R2HGylation identified as a post-translational modification in R2HG-elevated cancers

R-2-Hydroxyglutarate (R2HG), an oncometabolite predominantly produced by mutated isocitrate dehydrogenase 1/2 (IDH1/2) in various cancers, is known to drive cancer progression through noncovalent inhibition of -ketoglutarate (KG)-dependent enzymes. In this work, we propose an alternative mechanism wherein R2HG contributes to cancer development via covalent modification of biologically critical lysines, a process termed lysine-R2HGylation (KR2HG). We designed and synthesized R2HG-mimicking probes, demonstrating their effectiveness in facilitating KR2HG target profiling and site mapping. We identified KR2HG as a previously unrecognized post-translational modification, confirmed its C5-linkage on GSTP1(K209), and demonstrated that SIRT5 functions as a deacylase for GSTP1-KR2HG in vitro. Furthermore, we found that R2HG slightly but significantly inhibits the enzymatic activity of GSTP1 through KR2HG and dramatically suppresses monocyte differentiation via this catalytically important lysine modification. Our findings provide an alternative perspective on the role of R2HG in leukemia progression and offer a practical tool for the clinical investigation of R2HG-elevated cancers.