Protein-Protein Interaction Networks: Structures, Evolution, and Application to Drug Design

Since proteins exert their functions through interaction with other proteins rather than in isolation, networks of protein interactions are inevitable for understanding protein functions, disease mechanisms, and discovering novel targets of therapeutic drugs (Hase et al. 2009, Barabasi et al. 2011, Vidal et al. 2011). With the recent influx of genome-wide data of protein interactions, many researchers have studied on the structures and statistics of protein-protein interaction networks (PINs). To discover novel drug target genes, it is informative to understand topological and statistical characteristics of PINs, and how disease and drug target genes are distributed over the networks. Moreover, because those statistical properties of PINs are the results of long-term evolution, analysis of the PIN architecture from the viewpoint of comparative genomics and molecular evolution is of particular importance.