title: Positive and negative regulatory roles of the WW-like domain in TEL-PDGFbetaR transformation.
abstract: TEL-platelet-derived growth factor-beta receptor (TEL-PDGFbetaR) is expressed in chronic myelomonocytic leukemias associated with t(5;12)(q33;p13), and the fusion tyrosine kinase retains a conserved WW-like domain in the PDGFbetaR autoinhibitory juxtamembrane region. Here we report that mutation of the 2 conserved tryptophan residues of the WW-like domain has opposing effects on TELPDGFbetaR kinase activation. Alanine substitution of W593, essential for protein-protein interaction in the context of other WW domains, impaired TEL-PDGFbetaR-mediated transformation of hematopoietic cells due to inhibition of TEL-PDGFbetaR kinase activity. In contrast, alanine substitution of W566, essential for structural integrity of WW domain in other contexts, had no effect on TEL-PDGFbetaR activation and oncogenic activity. Surprisingly, however, the W566A mutation suppressed the W593A phenotype. Double mutant W566A/W593A was indistinguishable from the wild-type fusion protein with regard to kinase activity, ability to confer factor-independent growth to Ba/F3 cells, or ability to induce a myeloproliferative disease in mice. Additional mutational analysis identified other substitutions within the WW-like domain in addition to W566A that could also suppress the W593A phenotype, including mutations predicted to diminish the autoinhibitory function of the juxtamembrane region. Therefore, the WW-like domain in the context of TELPDGFbetaR may have both positive and negative regulatory roles in kinase activation.
authors.affiliation: Division of Hematology, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Ifor R
authors.initials: IR
authors.lastname: Williams
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Kutok
authors.forename: Nicole
authors.initials: N
authors.lastname: Duclos
authors.forename: Ema
authors.initials: E
authors.lastname: Anastasiadou
authors.forename: Shane C
authors.initials: SC
authors.lastname: Masters
authors.forename: Haian
authors.initials: H
authors.lastname: Fu
authors.forename: D Gary
authors.initials: DG
authors.lastname: Gilliland
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002471:Cell Transformation, Neoplastic; D006801:Humans; D015477:Leukemia, Myelomonocytic, Chronic / Q000235:genetics* / Q000378:metabolism*; D008024:Ligands; D051379:Mice; D008969:Molecular Sequence Data; D015514:Oncogene Proteins, Fusion / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D010641:Phenotype; D010766:Phosphorylation; D017434:Protein Structure, Tertiary
chemical_list: D008024:Ligands; D015514:Oncogene Proteins, Fusion; C120888:TEL-PDGFRbeta fusion protein, human