Activation of RAS in myeloid leukemia cell lines.

Lysates of myeloid leukemia cell lines were subjected to affinity precipitation (AP) with GST-RBD as described in “Materials and methods.” RAS proteins were detected by immunoblotting with H-, K-, and N-RAS antibodies. H-RAS (L61)–transformed NIH-3T3 fibroblasts were used as a positive control for activated H-RAS.