Protein-protein interaction (PPI) network analysis

The search tool for the retrieval of interacting genes (STRING) is used to provide information regarding predicted and experimental interactions of proteins and the prediction method of this database is from neighborhood, gene fusion, co‑occurrence, co‑expression experiments, databases, and text mining. By setting the Combination score >0.4 as the reliability threshold value, the web based STRING database (http://string-db.org/) was used to produce PPI predictions after uploading the union gene list to the search bar.23 Based on the interplayed relationships, a PPI network was established and then visualized using the Cytoscape software.44 The connectivity degree of each protein, namely the number of proteins it connected, was calculated to evaluate its importance in this network.