FMK is an irreversible inhibitor of the CTD of RSK1 and RSK2 with IC50 of 15 nM for wt RSK2.
FMK shows 600- and 200-fold selectivity over the C436V and T493M mutants, respectively.
FMK inhibits EGF-induced Ser386 phosphorylation of endogenous RSK2 in COS-7 cells (IC50=200 nM).
FMK also potently inhibits a Fyn mutant in which Val285 was replaced with Cys(IC50=100 nM), weakly inhibits WT Fyn with IC50 of 4 uM.
