Construction of the FLAG-RIOK3 expression construct is detailed in the supplementary methods. Immunoprecipitation was done using anti-FLAG® M2 magnetic beads (Sigma-Aldrich). Antigen and bound interacting species were eluted using either FLAG peptide or heating the beads to 70°C for 10 min in denaturing LDS buffer. Gels were stained using ProteoSilver™ Plus Silver Stain Kit (Sigma-Aldrich). Bands were excised from the gel, digested with trypsin and subjected to tandem mass spectrometry (LC-MS/MS) analysis as described previously.40 (link)