Recombinant renilla reniformis system for bioluminescence resonance energy transfer

The invention relates to compositions comprising a first fusion protein comprising a first polypeptide domain and a R. reniformis luciferase and a second fusion protein comprising a second polypeptide domain and a R. reniformis GFP. The invention also relates to compositions comprising one or more polynucleotides encoding a first fusion protein comprising a first polypeptide domain and a R. reniformis luciferase and a second fusion protein comprising a second polypeptide domain and a R. reniformis GFP. The invention also relates to methods and kits for detecting protein-protein interactions, determining the location of a protein-protein interaction, identifying cells wherein there is a protein-protein interaction of interest, and screening for a candidate modulator that increases or decreases the amount of a protein-protein interaction.