P53-BRCT interactions. (a) The subnetwork of the protein-protein interaction network spanning only the human proteins with p53 and BCRT domains. Three pairs of these proteins interact (as indicated by connecting edges). The domain composition of each protein is given in the corresponding box. PE correctly identifies BRCT-p53 as interacting partners. (b) Crystal structure of the p53-BCRT complex (PDB entry 1gzh); only the p53 and BRCT domains are shown in the figure.