The NPM-ALK peptide interacts with the hydrophobic surface of the PTB domain and intermolecularly extends the PTB beta-sheet.     ///    "One of the interacting partners of NPM-ALK is the adaptor protein, Suc1-associated neurotrophic factor-induced tyrosine-phosphorylated target (SNT), and mutations that deprive NPM-ALK of all three of the SNT-binding sites significantly reduced the transforming activity. "    ///    "First, by isothermal titration calorimetry, we found that the phosphorylation-independent binding site in NPM-ALK interacts with the SNT-2 PTB domain more tightly than the phosphorylation-dependent binding sites. "    ///    "Second, the solution structure of the SNT-2 PTB domain in complex with the nonphosphorylated NPM-ALK peptide was determined by nuclear magnetic resonance spectroscopy. "    ///    "In this study, the interactions of the three binding sites in NPM-ALK with the phosphotyrosine binding (PTB) domain of SNT-2 were analyzed. "