a, By combining experimentally determined interaction stoichiometry between a bait A and a prey B (SbaitA<preyB) and their cellular abundance it is possible to calculate a ‘reciprocal’ stoichiometry in which B and A behave as the bait and the prey, respectively. b, Dot plots representing the interaction stoichiometries of the predicted GRB2 interactome (left, FDR ≤ 3%, ranked by maximum predicted stoichiometries) and of the experimentally determined GRB2 interactome (right, no FDR restriction). Note that the repertoire of preys of the predicted GRB2 interactome is confined to the repertoire of OST-tag baits capable of binding to GRB2. See Key in Fig. 2b legend. c, Global comparison of experimentally determined and of predicted interaction stoichiometries corresponding to the 15 baits showed a correlation coefficient of 0.66 and a median ratio of measured against predicted interactions stoichiometries of 3.7.