Involvement of Fyn, PI3K, and Rac2 in F-actin remodeling in response to SCF-induced integrin engagement. fyn^+/+, fyn^−/−, and fyn^−/− transduced with either MSCV-Fyn, MSCV-Rac2^V12, or MSCV-p110^CAAX BMMCs were plated on glass coverslips, previously coated with fibronectin. Cells were then activated with SCF for 1 minute at 37°C, prior to fixation and Rac2 and F-actin staining, as described in “Materials and methods.” Images were acquired by confocal microscopy, and representative images are shown.