Phosphorylation studies of CD34⁺ cells.

Western blot analysis of MAPK p42/44 phosphorylation (A), AKT phosphorylation (B), and STAT-5 phosphorylation (C) in normal human CD34⁺ cells. Cells were nonstimulated (lane 1) or stimulated for 10 minutes by 100 ng/mL TPO (lane 2) or for 1 minute by 500 ng/mL SDF-1 (lane 3). Equal loading in the lanes was evaluated by stripping the blot and reprobing with anti-MAPK p42/44, AKT, and STAT-5 antibodies (lower panels). The experiment was repeated 3 times with similar results.