Selectivity Profiling Using K192 Assay at UNC. The NanoBRET Target Engagement K192 Kinase Selectivity assay was performed as previously published with modifications detailed below. Kinases are grouped according to K10 tracer concentrations. A top control well (tracer and DMSO control) defined the maximum BRET/0% fractional occupancy, and a sample well (tracer and compound) was prepared for each kinase. Bottom control wells (expressing NanoLuc control vector pNL1.1.CMV[Nluc/CMV]) defined zero BRET/100% fractional occupancy. Reagents were provided by Promega (Promega #NP4060).