Each protein kinase was assayed in duplicate at 0.1 mM ATP in the presence and absence of 10 μM solenopsin. The results are presented as the percentage of activity remaining in the presence of solenopsin (average of duplicate determinations). Similar results were obtained in another independent experiment. Each protein was expressed, purified, and assayed as described previously.^26,32  MKK indicates MAPK kinase; ERK, extracellular signal-related kinase; JNK, c-Jun N-terminal kinase; RSK, p90 ribosomal S6 kinase; MAPKAP-K2, MAPK-activated protein kinase 2; MSK, mitogen- and stress-activated kinase; PRAK, p38-regulated/activated kinase; PKA, cAMP-dependent protein kinase; PKC protein kinase C; PDK1, 3-phosphoinositide–dependent protein kinase 1; AKT1, protein kinase Bα; SGK, serum and glucocorticoid-induced protein kinase; S6K, p70 ribosomal protein S6 kinase; GSK3, glycogen synthase kinase-3; ROCK, Rho-dependent kinase; AMPK, AMP-activated protein kinase; CHK1, checkpoint kinase 1; CK2, casein kinase 2; PHK, phosphorylase kinase; LCK, lymphocyte kinase; CSK; C-terminal Src kinase; CDK2, cyclin-dependent kinase 2-cyclin A complex; DYRK, dual specificity tyrosine phosphorylation regulated kinase; and PP2a, protein phosphatase 2A.