Chemically Responsive Protein Switches for the Precise Control of Biological Activities

Controlling the proximity or interaction of proteins with small molecules enables researchers to chemically regulate cellular functions. Here, we leveraged CATCHFIRE (chemically assisted tethering of chimera by fluorogenic induced recognition)─a technology enabling the chemical induction of dimerization in a reversible manner─to create chemically responsive protein switches for the precise and reversible control of various biological activities. CATCHFIRE allowed us to chemically induce the assembly and thus function of various split enzymes─including luciferases, proteases, and DNA recombinases. We extended this approach to develop CATCH-ON, a chemically inducible gene expression system relying on the chemically induced dimerization of the DNA-binding domain GAL4 and the truncated transcription factor p65Δ. CATCH-ON allowed us to precisely regulate the expression of cellular enzymes such as proteases, DNA recombinases, or suicide switches, as well as to control the secretion of therapeutically relevant proteins such as insulin. We showed that the CATCH-ON system is fast-acting, reversible, titratable, nontoxic, and compatible with other chemically induced dimerization systems, opening exciting possibilities for its application in basic research, biotechnology, and cell therapy.