Fig. 3: Mesoscale analysis of virus–host interactions.

Different methods to detect the mesoscale functional organization of human PPI (protein–protein interactions) highlight the impact of viral interactions on the human interactome in terms of variations in the number of modules, modularity, and hierarchical levels. Axis with virus labels is shared between all panels. a The method based on multiscale modularity maximization (Louvain) shows that viral interactions can significantly disrupt modules, leading to a higher number of smaller modules, while reducing modularity in most of the cases. The relative impact is relevant for SARS-CoV-2 and Influenza A. b The degree-corrected stochastic block model (DCSBM) shows a more heterogeneous pattern, where isolation of targeted proteins can lead to the merging of communities and more modular structure, or vice versa. c The number of levels (N Levels) of the hierarchical structure of targeted interactomes is presented, compared to the un-targeted reference structure (human PPI, dashed red line). Virus–host interactions often lead to a shallower hierarchical arrangement of communities.