Figure 1. Eps8 and IRSp53 effector network.

Network showing the main interactors of Eps8 and IRSp53 involved in the regulation of filopodia formation. Black filled dots indicate substrates of a reversible binding reaction, whose product is pointed by an arrow. Turnover of filamentous actin (reaction (9)) is the only irreversible reaction depicted in the diagram. In the network, we identify two different modules, a capping module, which includes the binding reactions between cappers and barbed ends, and a bundling module, which includes the binding reactions between bundlers and filamentous actin. CP represents Capping Protein, cyan circles are polymerized monomers of actin; the red circle marked Ga is G-actin. B and P mark the barbed and pointed ends, respectively, of a filament of actin. Reaction numbers and the shortened names in parentheses under the icons allow an easy interpreation of the equations of the model (Table 1 in Text S1).