Quantitative Modeling of GRK-Mediated β2AR Regulation
Figure 3
Validation of the model with two sets of experimental results.
Validation of the simulations (continuous lines) of the model shown in Figure 1, with experimental data obtained in HEK 293 cells stably overexpressing the FLAG WT β2AR (discrete data points). (A) Desensitization of β2AR stimulation of adenylyl cyclase after treatment with 10 µM ISO. Inset shows desensitization obtained on 30 nM ISO stimulation. Red – simulated results; Black – WT cells; Blue - cells stably overexpressing β2AR lacking PKA phosphorylation sites (PKA-). At lower concentrations the model matches PKA- desensitization more closely since it does not include PKA-mediated β2AR desensitization. (B) Resensitization of the β2AR stimulation of adenylyl cyclase. WT β2AR were stimulated with 1µM ISO for 15 min, followed by addition of metoprolol as described in methods. Dotted line shows simulated % activity of the β2AR when ligand dissociation from arrestin-bound receptor complex is reduced by ten-fold.