Increased amounts of phosphorylated Bcr-Abl and Stat5 protein in kinase inhibitor-resistant sublines growing in the presence of inhibitor. (A) Ba/F3-BA-wt cells (BA wt original), sublines derived from the PD166326 screen harboring mutations as indicated (screen), and Ba/F3 cells freshly transfected with Bcr-Abl E355G (E355G retransfected) were cultured without and in the presence of 25 nM PD166326. Whole cell lysates were analyzed for content of phosphorylated and total Bcr-Abl, phosphorylated Stat5, and actin. (B) Shift of dose-response of Ba/F3 cells transformed with engineered E355G in the presence of PD166326 compared with the subline derived from the screen expressing E355G. Ba/F3-BA-wt (+), Ba/F3 Bcr-Abl E355G screen (⋄), and Bcr-Abl E355G retransfected (▵) were processed as in Figure 4.