Abstract: The invention provides methods for isolating a modified peptide from a complex mixture of peptides, the method comprising the steps of: (a) obtaining a proteinaceous preparation from an organism, wherein the preparation comprises modified peptides from two or more different proteins; (b) contacting the preparation with at least one immobilized modification-specific antibody; and (c) isolating at least one modified peptide specifically bound by the immobilized modification-specific antibody in step (b). The method may further comprise the step of (d) characterizing the modified peptide isolated in step (c) by mass spectrometry (MS), tandem mass spectrometry (MS-MS), and/or MS3 analysis, or the step of (e) utilizing a search program to substantially match the spectra obtained for the modified peptide during the characterization of step (d) with the spectra for a known peptide sequence, thereby identifying the parent protein(s) of the modified peptide.

Abstract: In accordance with the invention, a novel gene translocation, (4p15, 6q22), in human non-small cell lung carcinoma (NSCLC) that results in a fusion proteins combining part of Sodium-dependent Phosphate Transporter Isoform NaPi-3b protein (SLC34A2) with Proto-oncogene Tyrosine Protein Kinase ROS Precursor (ROS) kinase has now been identified. The SLC34A2-ROS fusion protein is anticipated to drive the proliferation and survival of a subgroup of NSCLC tumors. The invention therefore provides, in part, isolated polynucleotides and vectors encoding the disclosed mutant ROS kinase polypeptides, probes for detecting it, isolated mutant polypeptides, recombinant polypeptides, and reagents for detecting the fusion and truncated polypeptides.