Differential phosphorylation of Ly108 isoforms. A-B. Ly108 was immunoprecipitated from intact thymi of C57Bl/6 and 129S6 mice using Ly108 mouse monoclonal antibody A, or αLy108-2 B, and treated with PNGase F. Western-blots were probed for phosphotyrosine (top) and stripped and re-probed with pan-αLy108 (bottom). Arrows indicate the 40 kDa marker. C. Ly108 was immunoprecipitated using αLy108 mouse monoclonal from pervanadate-treated SAP-expressing EL-4 cell lines expressing the Ly108-1, Ly108-2, novel Ly108-H1 isoforms or the empty vector. Ly108 immunoprecipitates were probed using 4G10 (top), pan-αLy108 (middle panel) and αSAP (lower panel). Relative intensities of pLy108/Ly108 and SAP/Ly108 are graphed. D. Ly108 was immunoprecipitated as in C, followed by treatment with PNGase F and immunoblotted for 4G10 (top) and pan-αLy108 (bottom panel). In parts C and D, the Ly108-H1 and vector control lanes were overloaded to ensure detection of phosphorylated Ly108-H1. Data are representative of 3 or more experiments.