Analysis of Shc, MAPK, and Akt phosphorylation in response to increasing TPO concentrations. UT-mplwt and UT-mpl▵7 cells were stimulated for 15 minutes (Shc) or 5 minutes (MAPK and Akt) with the indicated TPO conentrations, and phosphorylation of Shc, MAPK, and Akt was analyzed as described in the legend of Fig 5.