Structural Determinants of the Gain-of-Function Phenotype of Human Leukemia-associated Mutant CBL Oncogene.

Autor:	Nadeau SA; From the Eppley Institute for Research in Cancer and Allied Diseases.; the Departments of Genetics, Cell Biology and Anatomy., An W; From the Eppley Institute for Research in Cancer and Allied Diseases.; the Departments of Genetics, Cell Biology and Anatomy., Mohapatra BC; From the Eppley Institute for Research in Cancer and Allied Diseases.; Biochemistry and Molecular Biology., Mushtaq I; From the Eppley Institute for Research in Cancer and Allied Diseases.; Pathology and Microbiology, College of Medicine, and., Bielecki TA; From the Eppley Institute for Research in Cancer and Allied Diseases., Luan H; From the Eppley Institute for Research in Cancer and Allied Diseases.; the Departments of Genetics, Cell Biology and Anatomy., Zutshi N; From the Eppley Institute for Research in Cancer and Allied Diseases.; Pathology and Microbiology, College of Medicine, and., Ahmad G; From the Eppley Institute for Research in Cancer and Allied Diseases., Storck MD; From the Eppley Institute for Research in Cancer and Allied Diseases., Sanada M; the Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan., Ogawa S; the Department of Pathology and Tumor Biology, Kyoto University, Yoshida-Konoe-Cho, Sakyo-ku, Kyoto 606-8501, Japan., Band V; From the Eppley Institute for Research in Cancer and Allied Diseases.; the Departments of Genetics, Cell Biology and Anatomy.; the Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and., Band H; From the Eppley Institute for Research in Cancer and Allied Diseases, hband@unmc.edu.; the Departments of Genetics, Cell Biology and Anatomy.; Biochemistry and Molecular Biology.; Pathology and Microbiology, College of Medicine, and.; the Fred and Pamela Buffet Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska 68198 and.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2017 Mar 03; Vol. 292 (9), pp. 3666-3682. Date of Electronic Publication: 2017 Jan 12.
DOI:	10.1074/jbc.M116.772723
Abstrakt:	Mutations of the tyrosine kinase-directed ubiquitin ligase CBL cause myeloid leukemias, but the molecular determinants of the dominant leukemogenic activity of mutant CBL oncogenes are unclear. Here, we first define a gain-of-function attribute of the most common leukemia-associated CBL mutant, Y371H, by demonstrating its ability to increase proliferation of hematopoietic stem/progenitor cells (HSPCs) derived from CBL-null and CBL/CBL-B-null mice. Next, we express second-site point/deletion mutants of CBL-Y371H in CBL/CBL-B-null HSPCs or the cytokine-dependent human leukemic cell line TF-1 to show that individual or combined Tyr → Phe mutations of established phosphotyrosine residues (Tyr-700, Tyr-731, and Tyr-774) had little impact on the activity of the CBL-Y371H mutant in HSPCs, and the triple Tyr → Phe mutant was only modestly impaired in TF-1 cells. In contrast, intact tyrosine kinase-binding (TKB) domain and proline-rich region (PRR) were critical in both cell models. PRR deletion reduced the stem cell factor (SCF)-induced hyper-phosphorylation of the CBL-Y371H mutant and the c-KIT receptor and eliminated the sustained p-ERK1/2 and p-AKT induction by SCF. GST fusion protein pulldowns followed by phospho-specific antibody array analysis identified distinct CBL TKB domains or PRR-binding proteins that are phosphorylated in CBL-Y371H-expressing TF-1 cells. Our results support a model of mutant CBL gain-of-function in which mutant CBL proteins effectively compete with the remaining wild type CBL-B and juxtapose TKB domain-associated PTKs with PRR-associated signaling proteins to hyper-activate signaling downstream of hematopoietic growth factor receptors. Elucidation of mutant CBL domains required for leukemogenesis should facilitate targeted therapy approaches for patients with mutant CBL-driven leukemias. (© 2017 by The American Society for Biochemistry and Molecular Biology, Inc.)
Databáze:	MEDLINE
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