The effect of Src inhibition on translation initiation. MDA-MB-231 cells and MDA-MB-435/ β4 cells were treated with DMSO or 10 μM PP2 for 24 hr. Cell lysates were separated into 12 fractions on sucrose gradients as described in the Methods. The distribution was continuously recorded by absorbance at A254nm. The polysome profiles were showed as peaks. 1 through 7 represents light polysomes (untranslated mRNA and initiation complex) and 8 through 12 represents heavy polysomes (translated mRNA). Numbers indicates fraction numbers. The results are obtained from three independent experiments.