[14] Detection of protein-protein interactions by protein fragment complementation strategies

This chapter presents the basic concept of protein fragment complementation assays (PCAs) and how they are designed, with particular attention to the system developed based on murine dihydrofolate reductase (mDHFR). It then discusses several applications of the assay, including a simple, large-scale library-versus-library screening strategy in Escherichia coli. The implementation of mammalian assays is discussed, including applications to the quantitative detection of induced protein interactions and allosteric transitions in intact cells. Finally, the generality of the PCA strategy is demonstrated with examples of assays that are designed on the basis of other enzymes including glycinamide ribonucleotide transformylase, aminoglycoside kinase, and hygromycin B kinase.