samples. 4× LDS buffer (Life Technologies) containing β-mercaptoethanol was added to 20 µg of lysate. Samples were subjected to electrophoresis and western blotting using the NuPAGE® Novex® Tris-Acetate mini gels (Life Technologies) and the ECL Plus western blotting detection system (GE Healthcare, Piscataway, NJ) according to manufacturer's instructions. Western blots were probed with ALK-c antibody (for mouse ALK, ab650, Abcam, Cambridge, MA) diluted 1∶500 in 5% bovine serum albumin or with Drosophila ALK rabbit antibody [27] diluted 1∶5000 in 5% milk. Blots were probed with HRP-conjugated secondary antibodies (rabbit or mouse, GE Healthcare) diluted 1∶5000, then stripped using Restore Plus™ Western blot stripping buffer and re-probed with an antibody to GAPDH or Tubulin (Thermo Fisher Scientific).
