IC50 Values from ICW Assays Correlate Well with Published Values
||CREB ap pKB
||cAMP ap pKB
|Radioligand binding assay
Table 1. pKi, the negative log of the inhibition constant of a drug; pKB, the negative log of the dissociation equilibrium constant for a competitive antagonist; ap, apparent; CREB, cAMP response element binding protein. Selkirk JV et al. J. Biomol. Screen. 11: 351 (2006).
Comparison to GPCR Activity Assay
GPCR activity assays primarily monitor upstream signaling events, such as accumulation of cyclic AMP (cAMP). Downstream events, such as phosphorylation of cAMP response element binding protein (CREB), may also be useful readouts.1-2
In a 2006 study, the In-Cell Western method was used to quantify CREB phosphorylation.1 Potencies of agonists and antagonists correlated well with radioligand binding affinities and cAMP accumulation assays.
For the GPCR antagonist KW6002, the results in Table 1 were obtained.
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