Figure 3
DP1 and DP2 receptor differ remarkably in their deactivation kinetics upon PGD2 withdrawal. We performed single cell FRET measurements of HEK293T cells transiently transfected with either DP2 or DP1 receptor sensor construct measured at an inverted fluorescence microscope under constant flow using a pressurized perfusion system. Depicted is an example trace of the time course of the DP2 receptor sensor activation induced upon PGD2 application and subsequent receptor deactivation upon agonist withdrawal (A). (B) shows the extract from the curve shown in (A) used to fit to a mono-exponential function to determine the kinetics of receptor activation. (C) shows the extract from the curve shown in (A) used to fit to a mono-exponential function to determine the kinetics of receptor deactivation. (D) shown is an example trace of the time course of DP1 receptor sensor activation and deactivation measured side by side to the measurements shown in (A). (E,F) show the respective extract of the curve shown in (D) used to calculate receptor (de)activation kinetics respectively. (G,H) Halftimes determined by fitting of individual experiments of (G) activation kinetics (P value 0.0011**, unpaired t test) and H) deactivation kinetics (P value < 0.0001****, unpaired t test with Welch's correction) are displayed as mean ± SEM (n = 8–9 per condition).
