Mutations in genes encoding cell signaling proteins contribute to many cancers. For example, a chromosomal translocation fuses t
he Bcr gene to the Abl gene, leading to a constitutively active Bcr–Abl kinase and chronic myeloid leukemia (CML). CML is successfully treated with the drug imatinib (trade name Gleevec), which mimics an Abl kinase substrate and thus inhibits kinase activity. What normal cell molecule, and kinase substrate, does Gleevec mimic?
Imatinib is a small molecule kinase inhibitor. The BCR-ABL kinase can phosphorylate a series of downstream substrates, leading to proliferation of mature granulocytes. Bcr-Abl kinase substrate is the tyrosine. The Protein Tyrosine Kinase activity is an important requirement for malignant transformation, and that it cannot be complemented by any downstream effector, though not all interactions of BCR-ABL with other proteins are phosphotyrosine dependent.
