The two-hybrid system: an assay for protein-protein interactions.

The two-hybrid system is a yeast-based genetic assay for detecting protein-protein interactions. It can be used to identify proteins that bind to a protein of interest, or to delineate domains or residues critical for an interaction. Variations on this methodology have been developed to clone genes that encode DNA-binding proteins, to identify peptides that bind to a protein and, potentially, to screen for drugs.