Cell Culture and Subcellular Fractionation

WM35 (laboratory of Joyce Slingerland) and CCRF-CEM-C7H2 (CEM) (laboratory of Reinhard Kofler) cells were grown in RPMI (Sigma-Aldrich, St. Louis, MO, USA), 10% FCS (PAA, Pasching, Upper Austria, Austria), penicillin/streptomycin (Sigma-Aldrich). HeLa, HeLa T-REx^TM (Invitrogen, Carlsbad, CA, USA), MDA-MB-231 (laboratory of Stephan Geley) and MEFs (laboratory of Nisar Malek) were cultured in DMEM (Sigma-Aldrich), 10% FCS (PAA), penicillin/streptomycin. Cells were irradiated in a UV Stratalinker^® 1800 (Stratagene^®, La Jolla, CA, USA). Cells were lyzed in Laemmli buffer^{80 (link)} or IP-buffer^{81 (link)} using an ultrasonic homogenizer (Sonoplus, Bandelin, Berlin, Germany). Subcellular fractionation was performed as previously described^{31 (link)}. Thymocytes were isolated from the thymus of a 4 weeks old male C57BL/6 mouse using a sterile cell strainer (#352360, BD). Single cells were grown in RPMI (Sigma-Aldrich), 10% FCS (PAA), 50μM β-mercaptoethanol (Sigma-Aldrich), 1mM pyruvate (Gibco^TM Life Technologies, Carlsbad, CA, USA), penicillin/streptomycin (Sigma-Aldrich) with or without dexamethasone (10⁻⁷M).