MS023 was identified to have high potency for type I PRMTs including PRMT1, -3, -4, -6, and -8 but was inactive against type II and type III PRMTs, protein lysine methyltransferases as well as DNA methyltransferases. The crystal structure of PRMT6 with MS023 indicated that MS023 bound to the substrate-binding site. Moreover, MS023 could potentially decrease the cellular levels of histone arginine asymmetric dimethylation. In cells, MS023 also ould reduce the levels of arginine asymmetric dimethylation and increase levels of arginine monomethylation and symmetric dimethylation. Therefore, MS023 is a useful chemical tool for testing the role of type I PRMTs in health and disease [1].