ARC interacts with caspase-2, -8, and Ced-3 but not with caspase-1, -3, and -9. (A) 293T cells were transfected with plasmids AU1-tagged caspase-2 or -8 and HA-tagged ARC. Lysates were immunoprecipitated with anti-AU1 antibody and immunoblotted with anti-HA antibody (Top). Total lysates (100 μg) were immunoblotted with anti-AU1 (Center) or anti-HA antibody (Bottom). (B and C) 293T cells were transfected with plasmids Flag-tagged caspase-1, -3, -9, or CED-3 and HA-tagged ARC. Lysates were immunoprecipitated with anti-Flag antibody and immunoblotted with anti-HA antibody (Top). Total lysates (100 μg) were immunoblotted with anti-Flag (Center) or anti-HA antibody (Bottom). (D) 293T cells were transfected with plasmids HA-tagged N-caspase-8 or C-caspase-8, and Flag-tagged ARC. Lysates were immunoprecipitated with anti-HA antibody and immunoblotted with anti-Flag antibody (Top). Total lysates (100 μg) were immunoblotted with anti-HA (Center) or anti-Flag antibody (Bottom).