Immunoprecipitation of Fas Complex

IP-FCM performed according to the previously described^{51 (link)} with slight modifications. Briefly, polystyrene beads (Spherotech) were coated with a monoclonal antibody against Fas (Apo-1-3) as described by manufacturer’s instruction. To capture Fas complex in the nucleus, IP beads were incubated with lysate of the nuclear fraction of SW480 cells and washed to remove excess lysate. The washed IP beads were incubated with unrelated IgG or a primary antibody against Fas, pY1068 EGFR, or pY705 STAT3 followed by a corresponding secondary antibody. Then the IP beads were analyzed by flow cytometry.