Effects of selected mutations in the conserved WW-like domain on TEL-PDGFβR activation. (A) Schematic diagram of selected mutations within the WW-like domain in TEL-PDGFβR. The numbering of mutations is as for native human PDGFβR. The conserved tryptophan residues are marked with stars. (B) Effects of selected mutations in the conserved WW-like domain on TEL-PDGFβR-transforming activity in Ba/F3 cells. Cells stably expressing distinct TEL-PDGFβR variants were treated with IL-3 withdrawal for 24 hours prior to analysis by cell viability assay. The relative cell viability was normalized to the viability of cells stably expressing wild-type TEL-PDGFβR. Data presented are mean ± standard error (n = 3). (C) Autophosphorylation of TEL-PDGFβR mutants in Ba/F3 cells. Ba/F3 cell lysates were probed by 4G10. Visualization of multiple bands in each lane may be due to the 2 alternative translational start sites in TEL gene and autophosphorylation of TEL-PDGFβR.¹⁰  The bottom panel shows similar level of expression of TEL-PDGFβR variants by Western blot.