Tudor-based Proteomic Strategy Pan-specifically Enriches and Identifies Protein Arginine Methylation

In current study, we developed a molecular affinity strategy based on the Tudor domain of SMN, a naturally occurring methylarginine reader protein, for comprehensive proteomic profiling of cellular arginine methylation. We demonstrated that the Tudor domain-based approach exhibits broad specificity for proteins harboring mono- or di-methylated arginines, encompassing both RGG/RG-rich and non-RG motifs, facilitating the discovery of novel methylation sites. Using this strategy, we identified asymmetric dimethylarginine (aDMA) at the N-terminal of eIF3D, an essential component of the eukaryotic translation initiation complex. Biochemical analysis revealed that aDMA modification at R99 of eIF3D plays a regulatory role in protein translation initiation. Our findings establish a generally applicable approach for proteomic profiling of arginine methylation and unveil its novel regulatory role for this modification in eukaryotic protein translation.