Figure 1.

Capacity of antagonist peptides to induce protein tyrosine kinase activity. AD10 cells (1 × 10⁷) were stimulated for 1 min at 37°C with antagonist (T102G) pulsed, agonist (PCC 88–104) pulsed, or unpulsed DCEK.ICAM APCs (1 × 10⁷). Anti-Fyn (A), Lck (B), or ZAP-70 (C) immunoprecipitates were subjected to in vitro kinase assays and analyzed by SDS/PAGE. Proteins were transferred to membranes and incubated with 1 M KOH for 1 h at 50°C. The tyrosine-phosphorylated proteins were analyzed by autoradiography (Upper). The numbers under the autoradiograph indicate the relative radioactivity normalized to the amount observed in unstimulated cells. The same membranes were immunoblotted with anti-Fyn, Lck, or ZAP-70 (Lower). Results are representative of three similar experiments.