Relation of essentiality and functionality of Yeast proteins with their centrality values in a PPI network

Dodi Fitra Chandra ( 1351205 )


It has long been investigated and understood that centrality of proteins in the context of protein-protein interaction (PPI) networks are related to their essentiality. In the present work we reconfirmed the relations between essentiality of yeast proteins and their centrality measures in a PPI network by following a different approach using the concept of the receiver operating characteristic (ROC) curve.

We evaluated the performance of various centrality measures by comparing the area under the ROC curves and the minimum distance of the ROC curves from the ideal optimum classification point where TPR (True Positive Rate) is 1 and FPR (False Positive Rate) is 0. We further investigated that the functions of yeast proteins also have some relations with their centrality measures. Different types of centrality values imply different types of importance of a node in a network.

By deeply examining different centrality values of yeast proteins we found that they are not highly correlated, which leaded us to hypothesize that centralities might have some relations with gene/protein functionalities. Indeed, we found that many of the clusters generated based on the pattern of centrality values are rich with similar function proteins. The statistical significance of the protein clusters was assessed by hyper-geometric p-values. Using the statistically significant clusters, we established links between pattern of centrality measures and protein functions.