Transformation of Myeloid Leukemia Cells to Cytokine Independence by Bcr-Abl Is Suppressed by Kinase-defective Hck

• Published in: The Journal of biological chemistry Vol. 275; no. 24; pp. 18581 - 18585
• Main Authors: Lionberger, Jack M., Wilson, Matthew B., Smithgall, Thomas E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16.06.2000; American Society for Biochemistry and Molecular Biology
• Subjects: Abl gene; Animals; BCR gene; Cells, Cultured; Cytokines - physiology; Fusion Proteins, bcr-abl - pharmacology; Hck protein; Humans; Leukemia, Myeloid - metabolism; Protein-Tyrosine Kinases - pharmacology; Proto-Oncogene Proteins - pharmacology; Proto-Oncogene Proteins c-hck; Signal Transduction; Spodoptera; src Homology Domains; src-Family Kinases - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.C000126200

Bcr-Abl is the constitutively active protein-tyrosine kinase expressed as a result of the Philadelphia translocation in chronic myelogenous leukemia. Bcr-Abl is coupled to many of the same signaling pathways normally regulated by hematopoietic cytokines. Recent work shows that Hck, a member of the Src tyrosine kinase family with myeloid-restricted expression, associates with and is activated by Bcr-Abl. Here we investigated the mechanism of Hck interaction with Bcr-Abl and the requirement for Hck activation in Bcr-Abl transformation signaling. Binding studies demonstrated that the Hck SH3 and SH2 domains are sufficient for interaction with Bcr-Ablin vitro. Hck binding localizes to the Abl SH2, SH3, and kinase domains as well as the distal portion of the C-terminal tail. To address the requirement for endogenous Src family kinase activation in Bcr-Abl signaling, a kinase-defective mutant of Hck was stably expressed in the cytokine-dependent myeloid leukemia cell line DAGM. Kinase-defective Hck dramatically suppressed Bcr-Abl-induced outgrowth of these cells in the absence of cytokine compared with a control cell line expressing β-galactosidase. In contrast, kinase-defective Hck did not affect cell proliferation in response to interleukin-3, suggesting that the effect is specific for Bcr-Abl. These data show that Hck interacts with Bcr-Abl through a complex mechanism involving kinase-dependent and -independent components and that interaction with Hck or other Src family members is essential for transformation signaling by Bcr-Abl.