Evolutionary Identifications of Functional Modules in Yeast Protein Interaction Network

Comprehensive data of protein interactions are suitable for large-scale identifications of functional units such as protein complexes and pathways. There have been the preceding studies to identify the functional units mainly by graph approaches and by co-expression. In this poster presentation, we propose the evolutionary approaches to identify the functional units in yeast protein interaction network [1]. By inferring the evolutionary birth periods of yeast proteins based on phylogenetic profile [2], we showed that hub proteins are entirely evolutionary new and suggested that protein interaction network evolved by modules that form the functional unit. It is consistent with the previous suggestion from the facts that two proteins tend to interact with each other if they are in the same or similar evolutionary categories [4]. Based on these insights, we attempted to show a possibility of the evolutionary approaches to identify the functional units in yeast protein interaction network mainly by examining the evolutionary organization of protein complexes and by examining the gene co-expressions as described below.