BMS-5 (LIMKi 3) is a potent LIMK inhibitor with IC50s of 7 nM and 8 nM for LIMK1 and LIMK2, respectively.

LIMK2:8 nM, LIMK1:7 nM

The protein kinase domains of human LIMK1 and LIMK2 are expressed as glutathione S-transferase fusion proteins using the Bac-to-Bac system in Sf9 cells. Compounds 1 to 6 (e.g., BMS-5) are assayed for inhibition of LIMK1 and LIMK2 protein kinase activity by radioactive phosphate incorporation into biotinylated full-length human destrin. Reactions are done with a concentration series of compound in 25 mM HEPES, 100 mM NaCl, 5 mM MgCl2, 5 mM MnCl2, 1 μM total ATP, 83 μg/mL biotinylated destrin, 167 ng/mL glutathione S-transferase-LIMK1, or 835 ng/mL glutathione S-transferase-LIMK2 in a total volume of 60 μL at room temperature for 30 min (LIMK1) or 60 min (LIMK2). Reactions are terminated by addition of 140 μL of 20% TCA/100 mM sodium pyrophosphate, and the precipitates are harvested onto GF/C unifilter plates. The radioactivity incorporated is determined using a TopCount after addition of 35 μL Microscint scintillation fluid[1]

Cell membrane asymmetry is measured. Nf2ΔEx2 MSCs plated in a 6-well format are incubated with 2 μM BMS-5 or DMSO vehicle for 24 hrs. Cell are harvested and assayed. Plasma membrane asymmetry is evaluated with the Violet ratiometric assay by flow cytometry[2] .

Rats [3]