Figure 1
From: Essentiality and centrality in protein interaction networks revisited
e-MDSet proteins follow the centrality-lethality rule. (A) In a toy network we defined a minimum dominating set (MDSet) as an optimized subset of nodes (red square symbol) from where each remaining (i.e. non-MDSet) node (gray circle symbol) can be immediately reached by one step. Therefore, each non-MDSet protein is connected to at least one MDSet protein. (B) After we calculated the corresponding MDSets in binary interaction networks of E. coli, S. cerevisiae and H. sapiens, we grouped proteins in bins of logarithmically increasing degree. In each bin we determined the fraction of essential proteins that participated in the underlying MDSet as well, allowing us to observe that essential MDSet proteins (e-MDSet) were preferably enriched among highly connected essential proteins in all organisms. In the inset of (C) we calculated the enrichment of essential proteins as a function of their degree in the binary protein interaction networks of E. coli, S. cerevisiae and H. sapiens. Generally, essential proteins in binary interactions failed to produce a significant trend in either organism. Focusing on the enrichment of MDSet proteins, however, we recovered a strong increasing trend that (D) was reinforced by focusing on e-MDSet proteins.