Figure 1.

Classical linear signaling versus the high-connectivity interactome. The high number and intricacy of protein-protein interactions revealed by the human interactome ^8-10 (Figure taken from http://www.unihi.org/) (right panel) and kinome ¹² is in contrast to the traditionally depicted linear signaling cascades, where each component of the pathway interacts with only a few others (left panel), from the membrane-localized receptor (elongated blue oval) to the nucleus (gray oval).