Protein Bundling to Enhance the Detection of Protein-Protein Interactions

Many key cellular processes, including transcriptional regulation, protein degradation, and signal transduction, are the outcome of the protein–protein interactions that occur in vivo. In almost all cases, the proteins that participate in these processes exist in multiprotein complexes, the formation of which is dependent on extensive protein–protein interactions. For example, the process of transcriptional activation of eukaryotic genes is dependent on the interaction of multiple transcriptional activators with dozens of proteins that are part of several multiprotein complexes, including TFIID, RNA polymerase, and chromatin-modifying complexes (Laemmli and Tjian 1996; Kingston 1999; Lemon and Tjian 2000). A large number of protein–protein interactions occurring in many biological processes have been identified in recent years, although they repre-