Functional interactions between cellular entities like genes, proteins, metabolites, etc. are the key drivers of cellular functions. Different experimental methods like chromatin immunoprecipitation (1) and two-hybrid assays (2), among others, have generated large amounts of interaction data for many organisms, usually stored in interaction databases. In the past few years, the analysis of interaction networks has become crucial to understand biological processes and their dysfunctions in human diseases. For example, reaction networks build the basis of computational models in systems biology. Analyses combining expression and interaction data have recently been used to reveal previously unknown disease mechanisms (3,4). Thus, collecting comprehensive human interaction data is the key to gain new insights into cell biology.
