Fig. 2: Membranes increase the affinity of EPAC1FL for cAMP and 007.
From: Membranes prime the RapGEF EPAC1 to transduce cAMP signaling
a, d EPAC1FL nucleotide exchange activity was measured in the presence of different concentrations of cAMP (a) in solution (purple) or on liposomes (green), or in the presence of different concentrations of 007 (d) in solution (blue) or on liposomes (red). Sigmoidal curves were fitted to the data using nonlinear regression, with all points considered independent. EC50 (arrows) and top values (dotted lines) of the curves were deduced from the regression and reported as KD ± SE (b, e) and kmax ± SE (c, f), respectively (n = 1 experiment including 32 (cAMP), 28 (007 in solution), or 24 (007 on liposomes) individual kinetics reactions per condition). Statistical analyses were performed by two-tailed unpaired Student’s t-tests with Welch’s correction. ***P < 0.001; ****P < 0.0001. Test statistics, mean values with 95% CI, effect sizes, and exact P values are in Supplementary Table 5. Source data are provided as a Source Data file.
