Figure 4
From: Identification of a Novel, Small Molecule Partial Agonist for the Cyclic AMP Sensor, EPAC1
GEF activity of EPAC1. (a) Time trace of the exchange reaction with 500 μM cAMP either 500 μM I178, I288, I516 or I942 where indicated. The data are fitted as single exponential decay with off-set (red lines) to obtain the rate constants kobs, as shown in (b). Rate constants from exchange reactions with either 500 μM or 50 μM cAMP, the presence or absence of 500 μM I178, I288, I516 or I942, as indicated, are presented as a bar graph (n = 4). (c) Exchange activity induced by cAMP, I942 or I178. The dependency of kobs on the concentration of cAMP (open triangles), I942 (closed circles) or I178 (open circles) is plotted on the left. The lower panel shows a magnification of the I942 and I178 induced activity. Inhibition of cAMP induced exchange activity by I942 and I178 is shown on the right. kobs were determined in the presence of 500 μM cAMP and various concentrations of I942 or I178.
