Imagine the possibilities! In an impressive feat of rational engineering and directed evolution, Spencer C. Alford et.al. from Bob Campbell’s lab at the University of Alberta developed ddRFP, a dimerization dependent bright new red that can be used to image protein-protein interactions in vitro!
This landmark paper, “A Fluorogenic Red Fluorescent Protein Heterodimer” demonstrates that the dimerization-dependent fluorescence of ddRFP can be used to detect protein-protein interaction in vitro. Their proof of principle describes imaging the reversible Ca2+-dependent association of calmodulin and M13 in live cells, and then goes way over the top by showing us how caspase-3 activity can be imaged during apoptosis with this unique single fluorophore sensor. Brilliant! And Red.
Check it out.