SCF induces chemotaxis of MO7e cells via a Src family kinase-mediated mechanism. SCF-induced chemotaxis was measured by a fluorescence-based assay using 96-well chemotaxis chamber plates (see Materials and Methods). Panel A depicts time-course analysis of SCF-induced (100 ng/mL) migration of MO7e cells. Panel B shows the concentration dependence of SCF-induced chemotaxis and PP1 (10 μmol/L) inhibition of SCF-induced chemotaxis of MO7e cells. The data are reported as the percentage of MO7e cells migrating into the lower chamber (mean ± standard deviation). The results are representative of three independent experiments that yielded similar results. The percentage of cells migrating in the presence of SCF plus PP1 was not different than the percentage of cells migrating in the control (P > .05, Student’s t-test).