Fig. 5. Overexpression of Rab22a affects endocytosis. (A) CHO cells transiently expressing GFP alone (vector) or GFP fused to Rab22aWT, Rab22aS19N and Rab22aQ64L were allowed to endocytose HRP for 1 hour. The cells were washed and the amount of peroxidase associated with the cells was measured. The uptake was expressed as a percentage of the HRP endocytosed by untransfected cells (control). (B) The same experiment was performed with CHO clones stably expressing Rab22a wild-type and the mutants. (C) CHO cells that had internalized ¹²⁵I-HRP as in A were washed and incubated for 40 minutes. The amount of HRP digested (dark gray bars) and recycled into the medium (light gray bars) was estimated from trichloroacetic acid soluble and precipitable radioactivity as explained under Material and Methods. The data are expressed as a percentage of HRP present in the cells after the internalization period. Black bars show the percentage of HRP that is lost from the cells by digestion and recycling. The data represent the mean±s.e.m. of five experiments. Asterisks indicate significant differences from the control (P<0.05).