On the functional and structural characterization of hubs in protein-protein interaction networks.

A number of interesting issues have been addressed on biological networks about their global and local properties. The connection between the topological properties of proteins in Protein-Protein Interaction (PPI) networks and their biological relevance has been investigated focusing on hubs, i.e. proteins with a large number of interacting partners. We will survey the literature trying to answer the following questions: Do hub proteins have special biological properties? Do they tend to be more essential than non-hub proteins? Are they more evolutionarily conserved? Do they play a central role in modular organization of the protein interaction network? Are there structural properties that characterize hub proteins?