Chen J, Williams IR, Lee BH, Duclos N, Huntly BJP, Donoghue DJ, Gilliland DG. Constitutively activated FGFR3 mutants signal through PLCgamma-dependent and -independent pathways for hematopoietic transformation.
Blood 2005;
106:328-37. [PMID:
15784730 PMCID:
PMC1895117 DOI:
10.1182/blood-2004-09-3686]
[Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Ectopic expression of fibroblast growth factor receptor 3 (FGFR3) associated with t(4;14) has been implicated in the pathogenesis of human multiple myeloma. Some t(4;14) patients have activating mutations of FGFR3, of which a minority are K650E (thanatophoric dysplasia type II [TDII]). To investigate the role of autophosphorylated tyrosine residues in FGFR3 signal transduction and transformation, we characterized a series of FGFR3 TDII mutants with single or multiple Y-->F substitutions. Phenylalanine substitution of Y760, essential for phospholipase Cgamma (PLCgamma) binding and activation, significantly attenuated FGFR3 TDII-mediated PLCgamma activation, as well as transformation in Ba/F3 cells and a murine bone marrow transplant leukemia model. In contrast, single substitution of Y577, Y724, or Y770 had minimal to moderate effects on TDII-dependent transformation. Substitution of all 4 non-activation loop tyrosine residues significantly attenuated, but did not abolish, TDII transforming activity. Similar observations were obtained in the context of a constitutively activated fusion TEL-FGFR3 associated with t(4;12)(p16;p13) peripheral T-cell lymphomas. Moreover, 2 independent EmuSR-FGFR3 TDII transgenic mouse lines developed a pro-B-cell lymphoma, and PLCgamma was highly activated in primary lymphoma cells as assessed by tyrosine phosphorylation. These data indicate that engagement of multiple signaling pathways, including PLCgamma-dependent and PLCgamma-independent pathways, is required for full hematopoietic transformation by constitutively activated FGFR3 mutants.
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