Fig. 2. Processing of D187N to C68 occurs in the Golgi. BHK cells were co-transfected with wild-type (ctl) or the D187N FAF variant (ctl, a–f) and the indicated Sar1, Arf1 or Rab GTPase mutants. Following expression, cells were washed, and the intracellular or secreted full-length C68 forms and recovered after a 2 h time period were analyzed by immunoblotting (A) and quantitated (B) as described in Materials and methods. Control (ctl) is the amount of wild-type or D187N secreted or processed in the absence of mutant GTPases. The results are typical of three independent experiments.