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Vempati, S. ; Reindl, C. ; Wolf, U. ; Kern, R. ; Petropoulos, K. ; Naidu, V.M. ; Buske, C. ; Hiddemann, W. ; Kohl, T.M. ; Spiekermann, K.

Transformation by oncogenic mutants and ligand-dependent activation of FLT3 wild-type requires the tyrosine residues 589 and 591.

Clin. Cancer Res. 14, 4437-4445 (2008)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Mutations in the receptor tyrosine kinase FLT3 are found in up to 30% of acute myelogenous leukemia patients and are associated with an inferior prognosis. In this study, we characterized critical tyrosine residues responsible for the transforming potential of active FLT3-receptor mutants and ligand-dependent activation of FLT3-WT. EXPERIMENTAL DESIGN: We performed a detailed structure-function analysis of putative autophosphorylation tyrosine residues in the FLT3-D835Y tyrosine kinase domain (TKD) mutant. All tyrosine residues in the juxtamembrane domain (Y566, Y572, Y589, Y591, Y597, and Y599), interkinase domain (Y726 and Y768), and COOH-terminal domain (Y955 and Y969) of the FLT3-D835Y construct were successively mutated to phenylalanine and the transforming activity of these mutants was analyzed in interleukin-3-dependent Ba/F3 cells. Tyrosine residues critical for the transforming potential of FLT3-D835Y were also analyzed in FLT3 internal tandem duplication mutants (FLT3-ITD)and the FLT3 wild-type (FLT3-WT) receptor. RESULT: The substitution of the tyrosine residues by phenylalanine in the juxtamembrane, interkinase, and COOH-terminal domains resulted in a complete loss of the transforming potential of FLT3-D835Y-expressing cells which can be attributed to a significant reduction of signal tranducer and activator of transcription 5 (STAT5) phosphorylation at the molecular level. Reintroduction of single tyrosine residues revealed the critical role of Y589 and Y591 in reconstituting interleukin-3-independent growth of FLT3-TKD-expressing cells. Combined mutation of Y589 and Y591 to phenylalanine also abrogated ligand-dependent proliferation of FLT3-WT and the transforming potential of FLT3-ITD-with a subsequent abrogation of STAT5 phosphorylation. CONCLUSION: We identified two tyrosine residues, Y589 and Y591, in the juxtamembrane domain that are critical for the ligand-dependent activation of FLT3-WT and the transforming potential of oncogenic FLT3 mutants.
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Publication type Article: Journal article
Document type Scientific Article
Keywords acute myeloid-leukemia; internal tandem duplication; acute myelogenous leukemia; tyrosine kinase inhibitor; src family kinases; stem-cell factor; autophosphorylation sites; constitutive activation; transcription proteins; juxtamembrane domain
ISSN (print) / ISBN 1078-0432
e-ISSN 1557-3265
Journal Clinical Cancer Research
Quellenangaben Volume: 14, Issue: 14, Pages: 4437-4445 Article Number: , Supplement: ,
Publisher American Association for Cancer Research (AACR)
Reviewing status Peer reviewed
Institute(s) CCG Pathogenesis of Acute Myeloid Leukemia (KKG-KPL)