Using Steady-State Fluorescence Anisotropy to Study Protein Clustering.

Signaling pathways rely on the precise control of protein-protein interactions. Therefore, it is essential to be able to investigate such interactions with spatiotemporal resolution and in live cells. Here we describe a microscope-based fluorescence spectrometry technique to investigate homotypic interactions between GFP-labeled fusion proteins in a rapid and reproducible fashion using fluorescence anisotropy. This method is of great value for the study of protein complexes in live tissue with subcellular resolution.