Updated project metadata. We used quantitative mass spectrometry-based proteomics to unravel global changes in the phosphoproteome upon treatment of ASP14 cells (a Ewing Sarcoma cell line) according to the setup below. The combination of drugs were experimentally shown to infer synergy in terms of cell killing. Three experiments were performed using a triple SILAC setup (Light: Lys0,Arg0; Medium: Lys4,Arg6; and Heavy: Lys8,Arg10): Experiment 1: Light SILAC: Drug combination (90 nM Midostaurin + 20 nM BMS-754807) Medium SILAC: Midostaurin (90 nM) Heavy SILAC: 0.1% DMSO Experiment 2: Light SILAC: Drug combination (90 nM Midostaurin + 20 nM BMS-754807) Medium SILAC: Midostaurin (90 nM) Heavy SILAC: BMS-754807 (20 nM) Experiment 3: Light SILAC: Drug combination (90 nM Midostaurin + 20 nM BMS-754807) Medium SILAC: BMS-754807 (20 nM) Heavy SILAC: 0.1% DMSO ASP14 cells were starved by replacing complete SILAC medium with SILAC minimal medium without serum over night. Cells were treated with drugs as stated above for 2h; then they were stimulated with serum for 20 minutes and harvested thereafter.