CD44 and CD147 contain sorting sequences that direct their traffic to recycling tubular endosomes. (A) HeLa cells were incubated with primary antibodies against endogenous CD44, endogenous CD147, or Tac for 1 h at 37°C to allow internalization of the cargo proteins. After fixation, cells were immunolabeled with antibodies to EEA1, followed by secondary antibodies to detect EEA1 (red) and cargo proteins (green). Insets show enlarged views of the boxed regions. (B) Schematic representation of Tac, CD44, and CD147 chimeras used to identify potential sorting sequences in these CIE cargo proteins. Tac sequences are in orange, CD44 sequences in green, and CD147 sequences in purple. (C) HeLa cells transfected with either Tac or the different chimeric proteins were incubated with anti-CD44, anti–rat CD147, or anti-Tac antibodies for 1 h at 37°C to allow internalization of the antibody-bound cargo. Immunofluorescence analysis of all experiments was performed as described in Materials and methods. Arrows in A and C point to tubular endosomes. Bars: (A and C) 10 µm; (insets) 3 µm.