SDF-1 phosphorylates STAT-3 at Ser727 but not at Tyr705 in α_IIbβ₃⁺ cells.

Western blot analysis of STAT-3 phosphorylation at Tyr705 (A) and at Ser727 (B) in normal human α_IIbβ₃⁺ cells. Cells were nonstimulated (lane 1) or stimulated with 100 ng/mL TPO (lanes 2, 4, 6, 8) or 500 ng/mL SDF-1 (lanes 3, 5, 7, 9) for 1 minute (lanes 2, 3), 10 minutes (lanes 4, 5), 30 minutes (lanes 6, 7), and 1 hour (lanes 8, 9). Equal loading in the lanes was evaluated by stripping the blot and reprobing with an anti–STAT-3 antibody. The experiment was repeated 3 times with similar results.