Both Ligand- and Cell-Specific Parameters Control Ligand Agonism in a Kinetic Model of G Protein–Coupled Receptor Signaling
Figure 4
The Effect of Changing Receptor and G Protein Expression on the Activation of G Protein
Dose response curves measuring the percent accumulation of GαGTP (%Accum) were calculated according to Equation 2 as described in Methods.
(A) Total G protein (Gtotal) is varied from 1,000,000/cell to 3,000 per cell, and Rtotal = 5,000/cell.
(B) Total receptor (Rtotal) is varied from 30,000 to 1,000 per cell, and Gtotal = 10,000/cell. Parameter values: k1 = 1 s−1, k3 = 1 × 107 M−1s−1, k11 =1 × 10−4 (number/cell)−1s−1, kGact = 5 s−1, kGTP = 1 s−1, kG = 1 × 10−4 (number/cell)−1s−1, Ka = 1 × 10−8 M−1, Kg = 1 × 10−4 (number/cell)−1, Kact = 0.01, α = 5, β = 5, δ = 0.5, γ = 0.1, η = 0.1.