Methods and assays for identifying compounds that modulate protein-protein interactions

A method to identify a compound that modulates a protein-protein interaction between a first protein and a second protein comprising:

• i) providing a first protein that is attached to a reporter activating protein that is arranged to be inactive, wherein the inactive reporter activating protein comprises a cleavage site for a protease that is interposed between two portions of the inactive reporter activating protein;
• ii) providing a second protein that is attached to a protease, wherein the protease is capable of cleaving the cleavage site in the inactive reporter activating protein;
• iii) providing a reporter whose signal is altered by the activity of an active reporter activating protein;
• iv) providing a test compound;
• v) reacting the test compound with the first protein, the second protein, and the reporter, causing the first protein to associate with the second protein, which association causes the protease to cleave the inactive reporter activating protein at the cleavage site, resulting in the two portions of the inactive reporter activating protein to be rearranged to be active and generate the active reporter activating protein, causing the active reporter activating protein to activate the reporter;
• and
• vi) measuring the signal generated by the activated reporter;
• wherein a change in the signal is indicative of the protein-protein interaction between the first protein and second protein.