Lysine- R 2HGylation identified as a post-translational modification in R 2HG-elevated cancers

R -2-Hydroxyglutarate ( R 2HG), 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 α-ketoglutarate ( α KG)-dependent enzymes. In this work, we propose an alternative mechanism wherein R 2HG contributes to cancer development via covalent modification of biologically critical lysines, a process termed lysine- R 2HGylation (K _{R 2HG} ). We designed and synthesized R 2HG-mimicking probes, demonstrating their effectiveness in facilitating K _{R 2HG} target profiling and site mapping. We identified K _{R 2HG} as a previously unrecognized post-translational modification, confirmed its C5-linkage on GSTP1(K209), and demonstrated that SIRT5 functions as a deacylase for GSTP1-K _{R 2HG} in vitro . Furthermore, we found that R 2HG slightly but significantly inhibits the enzymatic activity of GSTP1 through K _{R 2HG} and dramatically suppresses monocyte differentiation via this catalytically important lysine modification. Our findings provide an alternative perspective on the role of R 2HG in leukemia progression and offer a practical tool for the clinical investigation of R 2HG-elevated cancers.