Two categories of functional relationships. The two categories of functional relationships that we use in this study are physical interactions (specifically co-complex memberships) and metabolic interactions. The physical interactions (red) exist between proteins that are identified in the same protein complex, whereas the metabolic interactions (blue) exist between proteins that act in the same metabolic pathway. Metabolic interactions may also exist between individual members of a complex and proteins that act in the same pathway as this complex. One aspect of the nature of these to functional relationships is the physical distance between proteins as illustrated in the graph. As the nature of the relationships differs, one might expect differential behavior in high-throughput experiments.
van Noort et al. Genome Biology 2007 8:R197 doi:10.1186/gb-2007-8-9-r197