English: The differences between singleton and duplicate capacitors are illustrated by the protein-interaction subnetwork surrounding complexes involved in transcriptional activation. Shown is a subnetwork of the affinity-capture mass spectrometry interaction network that was created using all proteins annotated to be in the Mediator complex and their first-degree interaction neighbors. The subnetwork was displayed using Cytoscape (http://www.cytoscape.org/), with nodes placed by spring embedded layout. Nineteen nodes with only one interaction have been removed for clarity. Colors represent nonessential proteins (light grey), essential proteins (dark grey), singleton capacitors (light blue), duplicate capacitors (dark blue), and capacitors that cannot be categorized as singletons or duplicates (purple). Singleton capacitors are likely to be found in highly interconnected complexes such as the Mediator transcriptional coactivation complex, RNA polymerase II, the SAGA and TFIID complexes, and chromatin remodeling complexes. Other members of these complexes tend to be essential genes or capacitors. Duplicate capacitors are highly connected and tend to interact with multiple complexes. Interactions of the duplicate capacitor TAF14 are highlighted in purple.