Cells were treated with either DMSO, 1 μM or 10 μM MN714 for 6 h in 10 cm dish. Cells were harvested, washed with PBS and lysed in 500 μl ml RIPA buffer (Sigma-R0278: 150 mM NaCl, 1.0% IGEPAL® CA-630, 0.5% sodium deoxycholate, 0.1% SDS, 50 mM Tris, pH 8.0, and freshly added protease inhibitor tablet). Cellular debris was pelleted, the lysate supernatant was aspirated to a new tube and subjected to immunoprecipitation at 4 °C for 4 h with 3 μl anti-SOCS2 antibody coupled to 20 μl of protein A/G beads (abcam-ab109245). The beads were washed 3 times with 1x RIPA buffer and precipitated protein samples were eluted with 1 × NuPAGE™ LDS sample buffer, and 20% of the sample was analyzed by SDS-PAGE and western blot using a rabbit anti-SOCS2 primary antibody (abcam) and IRDye® 800CW donkey anti-rabbit IgG secondary antibody. The remaining precipitated protein samples were processed for mass spec analysis. In brief the samples were reduced with DTT and alkylated with Iodoacetamide and subjected to the SP3 protein clean up procedure . The samples were eluted from SP3 beads into digestion buffer (0.1% SDS, 50 mM TEAB pH 8.5, 1 mM CaCl2) and digested with trypsin at a 1:50 enzyme to protein ratio and peptide clean up were performed according to the SP3 protocol. Samples were eluted into 2% DMSO and dried under vacuum. The dried samples were suspended in 40 μl 1% formic acid (FA) and submitted for LC-MS/MS run.