Protein interaction networks.

All proteins that have at least one interaction in one of the seven original databases are reported (see Methods). The gold sets only include interactions derived from single-gene experiments or found in more than one high-throughput screening. The percentage of proteins with network information is calculated over the total unique genes for each species as reported in Table 1 and returns a rough indication of the completeness of the network. Hs, H. sapiens; Dm, D. melanogaster; Sc, S. cerevisiae; Ec, E. coli.