TEL/PDGFβR leukemogenesis is influenced by phosphotyrosine interactions. At the left is 1 chain of PDGFβR, showing tyrosine residues that become phosphorylated after ligand binding. The signaling complex is a dimer (only 1 chain is shown). Strongly interacting proteins are shown adjacent to the tyrosine residues to which they bind. As shown by STAT and PI3K, proteins can interact with multiple tyrosines. The right panels show TEL/PDGFβR and the mutant proteins analyzed by Tomasson et al. (2). Only tyrosine residues that were mutated in their work are shown. The phenotypes of mice receiving the wild-type and mutant constructs are listed below each construct. “ΔPNT” indicates deletion removing the pointed domain (indicated by the shaded box in TEL), which is necessary for oligomerization.