The SH2 domain is not required for activation of PI 3-kinase in hematopoietic cell lines by p210 Bcr/Abl.
Top: PI 3-kinase activity in antiphosphotyrosine immunoprecipitates from lysates of the 3 indicated parental cell lines and polyclonal populations of each line transformed with p210 wild-type or the indicated SH2 mutants was determined and expressed as fold increased activity relative to parental cells. Data represent mean and standard deviation from 3 independent experiments. Similar results were obtained with assays of anti-p85 immunoprecipitates or whole cell lysates (data not shown). Bottom: Representative autoradiographs of thin-layer chromatograms of lipid kinase assays from these cell lines. Only the region containing phosphorylated PI products is reproduced. The positions of PIP, PIP2, and PIP3 are indicated by arrowheads at left; only the PI 3,4,5-P3(PIP3) species is exclusively generated by PI 3-kinase and was used to calculate activity.
