Phosphorylation of NPM-ALK by pp60^c-src. Jurkat cells stably expressing the K210R kinase dead NPM-ALK mutant were transiently transfected with pSGT empty vector (lane 1) or pSGT SrcY527F hyperactive form of pp60^c-src. At 48 hours after transfection, cells were subjected to immunoprecipitation with the ALK1 antibody followed by immunoblot analysis with the antiphosphotyrosine 4G10 antibody. Data shown are representative of 2 independent experiments with identical results.