Artemis

After being washed with ice-cold PBS, cells were lysed with RIPA Lysis Buffer (VWR Life Science, Philadelphia, PA, USA), supplemented with Phosphatase Inhibitor Cocktail 2 (Sigma, St. Louis, MO, USA) and Protease Inhibitor Cocktail (Bimake, Houston, TX, USA). The Pierce BCA Protein Assay Kit (Thermo Scientific, Waltham, MA, USA) was used to determine protein concentration. Equal protein lysates were run on Novex 3–8% Tris-acetate 15 Well Mini Gels (Invitrogen, Carlsbad, CA, USA) and transferred to Immobilon-P membranes (Millipore, Burlington, MA, USA). Membranes were then probed with the following primary antibodies: GAPDH (Santa Cruz Biotechnologies, Dallas, TX, USA), DNA-PKcs (abcam, Cambridge, UK), phospho DNA-PKcs S2056 (abcam), Artemis (abcam), phospho Artemis S516 (abcam), XRCC4 (Santa Cruz Biotechnologies), Ligase IV (abcam), CD4 (abcam), and DYKDDDDK (FLAG) Tag (Invitrogen). After exposure to the matching HRP-conjugated secondary antibody, cells were visualized using SuperSignal West Femto Maximum Sensitivity Substrate (Thermo Scientific).