Detection of Membrane Protein Interactions by Cell-based Tango Assays.

The Tango assay is a protein-protein interaction assay, in which a transcription factor (rTA) is fused to a membrane-bound protein via a linker that contains a cleavage site for TEV protease, whereas a soluble interaction partner is fused to TEV protease (Barnea , 2008). Association between the two interaction partners leads to an efficient cleavage of the transcription factor, allowing it to translocate to the nucleus and activate a luciferase reporter gene as measurement of the interactions. In this modified assay, we fused one copy of the membrane-spanning amyloid precursor protein (APP) C99 region to TEV site-rTA (C99-TEV site-rTA) and a second copy to TEV protease (C99-TEV) to analyze intramembrane C99-C99 interaction in live cells.