Figure 1

Network structure of the extended model of vertebrate phototransduction. With respect to previous implementations (refs. [15, 19]), the new model accounts for more realistic molecular steps involved in the recovery after light activation. In particular, a detailed mechanism of Rec-mediated calcium feedback on RK was added (light green boxes) together with dynamic Arr oligomerization, leading to the formation of Arr dimers and tetramers (blue boxes). The biochemical reactions describing these new modules and the relative kinetic parameters are described in the Methods. Irreversible reactions are marked with an arrow indicating the direction of each reaction. The symbols are the same used in ref. [15].