In recent years, comprehensive studies of protein and domain networks have produced large amounts of interaction data. Further work has revealed that alternative splicing is a major cause of the observed protein and interaction diversity. Special microarrays now allow for measuring gene expression at the exon level, which enables the identification of alternative splicing events. We developed the Cytoscape plugin DomainGraph that facilitates the construction and visualization of protein and domain interaction networks. This plugin additionally supports the integration of exon expression data to highlight the effects of alternative splicing on the networks. We also designed and implemented a radial layout algorithm that specifically takes the integrated biological information for the networks into account and improves the visual presentation of the protein domain graphs considerably.