This model is from the article:
Competing G protein-coupled receptor kinases balance G protein and β-arrestin signaling
Heitzler D, Durand G, Gallay N, Rizk A, Ahn S, Kim J, Violin JD, Dupuy L, Gauthier C, Piketty V, Crépieux P, Poupon A, Clément F, Fages F, Lefkowit...