SLPs induce calcium flux, phosphorylation of AKT and MAPK p42/44, and actin polymerization. (A) Calcium flux studies of Fura-2–loaded normal human CD34⁺ cells. Cells were stimulated with 3% vol/vol SLP or SDF-1β (500 ng/mL), and subsequently calcium flux was evaluated using a spectrophotofluorimeter. Data presented are of a representative experiment that was repeated 3 times and yielded similar results. (B) SLP-induced phosphorylation of AKT and MAPK p42/44. BM CD34⁺ cells were stimulated by SDF-1 (200 ng/mL) (lane 2), by SLPs (3% vol/vol), or by SDF-1 (200 ng/mL) + SLP (3% vol/vol). (Lane 1) Nonstimulated cells. The experiment was repeated twice and yielded similar results. (C) Effect of SLPs on SDF-1–induced formation of filamentous actin. Purified CB CD34⁺ cells were stimulated with SDF-1 (100 ng/mL), 5% vol/vol SLPs, or both, and the formation of filamentous actin was analyzed by flow cytometry. Data are pooled from 3 independent experiments. *P < .001.