Interaction of an Src-kinase with NPM-ALK. (A) Ba/F3 N/A cells (10⁷ cells per point) were harvested at 0 and 6 hours after serum restimulation and subjected to immunoprecipitation with the 4G10 antibody followed by immunoblotting with the ALKc antibody (left panel). The same cells were used for immunoprecipitation with the ALK1 antibody followed by in vitro kinase (IVK) assay (right panel). (B) Ba/F3 N/A cells (10⁷ cells per point), at 0 and 6 hours after serum restimulation, were subjected to anti-Src immunoprecipitation using the Src-2 antibody followed by immunoblot analysis with the ALKc antibody. (C) ALCL-derived COST cells (10⁷ cells per point) were subjected to anti-Src immunoprecipitation followed by immunoblotting using the ALKc antibody (left panel) or the way inverse (right panel). The position of IgG heavy chain is indicated.