Fig. 1

Tyrosine 625 is critical for MPL W515L-induced TPO-independent cell proliferation and megakaryocyte hyperproliferation. a Diagram illustrates the wild-type MPL and four MPL mutants. Stars and numbers indicate mutation sites. b G1ME cells transduced with each construct were cultured without TPO. The cell numbers were counted over time and normalized to the starting cell numbers (Day 0) as proliferation rate. c WT bone marrow progenitor cells transduced with each construct were used for CFU-Mk assay. The bar graphs are the statistics of one representative experiment with duplicates from two independent experiments with similar results. Asterisk indicates significance (p < 0.05) and NS indicates non-significance compared to MPL W515L. d Cells were cultured in the absence of TPO and harvested for western blot to detect the phosphorylation and the expression level of each protein as indicated. Hsc70 is the loading control