Description:
<jats:sec><jats:label /><jats:p>Advances in our understanding of complex, sometimes interconnected, signaling networks will likely require the implementation of tunable perturbation techniques that enable sensitivity analyses of these circuits. We have developed a general experimental technique in which the stability of a specific protein is regulated by a synthetic small molecule. Mutants of the E. coli dihydrofolate reductase (ecDHFR) protein were engineered to be degraded when expressed in mammalian cells. Trimethoprim (TMP) is a high‐affinity ligand for ecDHFR that stabilizes fusion proteins in a predictable, dose‐dependent manner, allowing investigators to tunably regulate genetically engineered alleles of any protein of interest. DD‐regulated proteins are degraded very rapidly upon withdrawal of TMP, and protein levels in the absence of TMP are barely detectable. The ability of TMP to cross the blood‐brain barrier enables the tunable regulation of proteins expressed in cells found within the mammalian central nervous system.</jats:p></jats:sec>