c-Kit remains on the surface of PP1-treated cells. MO7e cells were preincubated without PP1 (A,B) or with PP1 (C,D) as described in Fig 1, then labeled with the 104D2 antibody. After a 30-minute incubation in SCF (200 ng/mL), the cells were fixed and labeled with goat antimouse IgG-FITC under conditions to detect cell surface c-Kit (A,C), or cell surface plus cytoplasmic c-Kit (B,D), as described in Materials and Methods.