Inhibition of MAPKAPK2 (unknown origin) assessed as remaining activity at 100 uM by radioactive filter binding assay in presence of [33P]-ATP relative to control
IMAP Assay: The ability of compounds to inhibit activated phospho-p38alpha is evaluated using a p38alpha /MK2 and a p38alpha /PRAK cascade assay format. The kinase activity of p38alpha is determined by its ability to phosphorylate GST-MK2 or GST-PRAK. Activation of MK2 or PRAK by p38alpha is quantitated by measuring the phosphorylation of a fluorescently-labeled, MK2/PRAK specific peptide substrate, Hsp27 peptide (FITC-KKKALSRQLSVAA). The phosphorylation of the Hsp27 peptide is quantified using IMAP technology (Molecular Devices, Sunnyvale Calif.). Kinase reactions are carried out in a 384-well plate (Greiner, 781280) in 20 mM HEPES pH 7.5, 10 mM MgCl2, 0.01% Triton X-100, 0.01% BSA, 1 mM DTT, and 2% DMSO. The inhibitor concentration is varied between 0.02-30,000 nM, while the Hsp27 peptide substrate and MgATP are held constant at 1 uM and 10 uM, respectively. Activated p38alpha is added to a final concentration of 30 uM for reactions with nonphosphorylated 1 nM GST-MK2.