Experimental strategies to improve drug-target identification in mass spectrometry-based thermal stability assays

In this study, we developed a model system for the assessment of small molecule-protein interactions using intact cells treated with a commercially available highly specific mitogen-activated protein kinase (MEK) 1/2 inhibitor to prepare a set of unfractionated test samples labeled with tandem mass tags. Our objective was to improve qualitative and quantitative aspects of MS-TSA as well as its efficiency and accuracy. We evaluated individually and for the first time in combination ΦSDM, FAIMS, and SIILCC as an improved MS-based acquisition approach for thermal stability assays (iMAATSA). PSM-level filtering was preliminarily investigated as an approach to reduce melting curve variation and improve the accuracy of Tm measurements.