Colocalization of IL-5Rα and syntenin in TF-1 cells. (A) Subcellular distribution of IL-5Rα (indicated in red) and EGFP-tagged syntenin (green) in TF-1 cells maintained in IL-3. Colocalization of IL-5Rα and syntenin is indicated in yellow in the right column (merge). A representative cell from 3 independent experiments is shown in the top panel. The bottom 3 panels show colocalizing structures at higher magnification. (B) Representative examples of EGFP-syntenin–expressing TF-1 cells that were stained for various endocytic markers in red. (C) TF-1 cells ectopically expressing GFP-syntenin were starved for 4 hours in 0.5% serum and incubated with IL-5 and an IL-5Rα–specific monoclonal mouse IgG for 60 minutes at 4°C (top panel), or for different time points at 37°C (bottom panels). Cells were then fixed, and stained using a Cy3-conjugated mAb recognizing mouse IgG (red). Representative examples are shown (n = 3).