The Use of Differential Scanning Fluorimetry to Assess Strigolactone Receptor Function

Differential scanning fluorimetry (DSF) is a method used for assessing the interaction of ligands with proteins. In most cases binding of a ligand to proteins tends to increase the melting temperature (T_m) of the protein involved. However, in the case of strigolactone receptors (e.g., D14, AtD14, DAD2, RMS3) from plants, the T_m tends to be reduced in the presence of strigolactones. This is likely due to increased flexibility of the receptors in the presence of hormone ligands.DSF experiments are simple, fast, amenable to high-throughput formats, and cost effective. They have therefore gained in popularity, including within the field of SL signaling. Typically in DSF the receptor protein is purified and incubated with the ligand (strigolactone, agonist, or antagonist) and a (fluorescent) reporter dye. The mixture is then placed in a quantitative PCR instrument and subjected to an increasing temperature gradient. Changes in fluorescence are recorded along the gradient, as the dye interacts with unfolded portions of the protein becoming accessible when the protein "melts". Differences in the temperature at which the protein unfolds in the absence and in the presence of the ligand are interpreted as indicating interactions between the ligand and the receptor.