Summry: Recent studies have revealed that alternative splicing plays an important role in the observed protein and interaction diversity. Spe-cial microarrays allow for measuring gene expression at the exon level and thus for studying alternative transcripts and their corre-sponding protein domain architecture. We have developed the Cytoscape plugin DomainGraph that enables the visualization and detailed study of domain-domain interactions forming protein inter-action networks. In addition, the integration of exon expression data supports the analysis of alternative splicing events and the charac-terization of their effects on the protein and domain interaction net-work. Different expression patterns between human tissues or cells can be identified by comparing the generated domain graphs. Availability: The plugin DomainGraph and the online documentation are avail-able at http://domaingraph.bioinf.mpi-inf.mpg.de. Contact: mario.albrecht@mpi-inf.mpg.de 10.1093/bioinformatics/btn437