(A) Actin and paxillin staining, as visualized by confocal microscopy, of untransformed and BCR/ABL-transformed hematopoietic cells in response to SDF-1. Cells were fixed and stained for actin using rhodamine-labeled phalloidin, and for paxillin using indirect immunofluorescent staining with the antipaxillin monoclonal antibody 5H11. Note the difference in shape and staining pattern of actin and paxillin in response to SDF-1 of normal Ba/F3 cells. There is no change in shape or staining pattern in response to SDF-1 for BCR/ABL-transformed Ba/F3 cells. The bar is 10 μm. (B) Scanning electron microscopy of untransformed and BCR/ABL-transformed hematopoietic cells in response to SDF-1. Ba/F3 cells and BCR/ABL-transformed Ba/F3 cells were either unstimulated or stimulated with SDF-1 and scanning electron micrographs were taken. Shown is the ruffling of an untransformed Ba/F3 cell; BCR/ABL containing cells had numerous extensions but there was no change in response to SDF-1. The bar represents 1.0 U.