PP1 does not impair SCF-induced association of c-Kit with clathrin. MO7e cells were incubated without or with PP1 as described in Fig 1, then treated without or with SCF for 5 minutes. The cells were lysed and immunoprecipitated with the SR-1 anti–c-Kit antibody, and analyzed by SDS-PAGE followed by immunoblotting with a polyclonal antibody specific for the clathrin heavy chain (A), or immunoblotting with a polyclonal antibody specific for c-Kit (B).