... presenting the pulse of Src activity in the plane of the inactive and active fractions, si and s1. If the duration of the stimulus exceeds the critical value, the trajectory in the (si, ... conformation, the SH2 domain binds to pYion the C-terminal tail, and the Src homology 3 (SH3) domain binds to the linkerbetween the SH2 and kinase domains at the back of the small lobe, preventing the ... by the addition of relevant phosphatases (or other Src activators, such as the SH2/SH3-ligands) [38] to activate step 1, followedby the addition of Csk and ATP to the reaction med-ium. At the...