Figure 3.

Cell surface levels of CD4-furin and FLAG-TGN38 in cells knocked down of BIG2 and/or BIG1, or AP-1. HeLa cells stably expressing CD4-furin (A) or FLAG-TGN38 (B) were mock-treated or treated with a pool of siRNAs for BIG1, BIG2, BIG1+BIG2, or μ1A. The cell surface levels of CD4-furin and FLAG-TGN38 were estimated as described in Materials and Methods. (A) Data represent mean ± SD of three independent experiments. (B) Data from one experiment. **p < 0.01. (C) FLAG-TGN38–expressing HeLa cells were mock-treated (left) or treated with a pool of siRNAs for BIG1+BIG2 (right), incubated with anti-FLAG M2 antibody at 19°C for 60 min to allow the antibody to accumulate in early endosomes, and chased for 90 min at 37°C. The cells were then stained for FLAG and golgin-97.