Cooperating interactions related to the cooperative pair of module 0 and module 4. This graph shows some of the interactions and crosstalk for module 0 (response to DNA damage stimulus) and module 4 (ubiquitin-dependent protein catabolism). Green circles indicate genes in module 0, and yellow circles indicate genes in module 4. Correlated genes of the cooperative module pair are represented by purple circles. Links represent regulatory interactions (red) and protein-protein interactions (blue) between two genes in the weighted physical interaction network (WPI network). Only crosstalk interactions and interactions with correlated genes are shown. RAD23 (YEL037C) is contained in module 4, and FKH2 (YIL131C) is a correlated gene of the module pair. The genes in module 4, particularly RAD23, are shown to interact directly with Module 0 and members of the 26S proteasome (contained in Module 4). Fkh1 regulates both module 0 and 4. By tracing crosstalk interactions between two modules and interactions with correlated genes, we can infer potential cooperating interactions of a module pair.