SILAC labeling of HL-60 cells

Stable isotope labeling of HL-60 cellular protein was conducted as described (Xiong and Wang 2010). Cells were cultured as two distinct populations in Iscove's modified Dulbecco medium (IMDM) lacking arginine and lysine (Thermo Scientific 88367) supplemented with either (1) 84 mg/L Arg0 (Sigma-Aldrich A6969) and 146 mg/L Lys0 (Sigma-Aldrich L9037) for the “light” population, or (2) molar equivalents of Arg10 (CIL CNLM-539-H) and Lys8 (CIL CNLM-291-H) for the “heavy” population. All populations of cells were maintained in 10% dialyzed FBS (Thermo Fisher 26400044) and 1× antibiotic–antimycotic (Thermo Fisher). Cells were passaged five times at a ratio of 1:4 and isotopic amino acid incorporation and Arg → Pro conversion were evaluated using LC-MS/MS prior to performing experiments.